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Nov. 20, 1953
J. A. BOYAJEAN, JR
2,575,546
MACHINE FOR PRODUCING SCREENED
RELIEF PATTERN PLATES
Filed July 24, 1948
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JOHN A. EOYAJEAN,J€
INVENTOR.
ATTORNEY
Nov. 209 1951
Filed July 24, 1948
J. A. BOYAJEAN, JR
2575546
MACHINE FOR PRODUCING SCREENED
RELIEF PATTERN PLATES
4 Sheets-Sheet 2
INVENTOR.
JO H N A. BOYAJEAN/(T':
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ATTORNEY
Nov. 20, 1951
J. A, BOYAJEAN, JR
2,575,546
MACHINE FOR PRODUCING SCREENED
RELIEF PATTERN PLATES
Filed July 24, 1948
4 Sheets-Sheet 3
4bFIG.
-
INVENTOR
JO N A. BOYAJ
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ATTORNEY
Nov. 20, 1951
Filed July 24, 1948
J. A. BOYAJEAN, JR
2,575,546
MACHINE FOR PRODUCING SCREENED
RELIEF PATTERN PLATES
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ATTORNEY
isatentecl Nov. .20, 1951
2,575,546
UNITED STATES PATENT OFFICE
2,57 5,546
MACHINE FOR PRODUCING SCREENED
RELIEF PATTERN PLATES
John A. Boyajean, Jr., Upper Montclair, N. J ., as
signor to Fairchild Camera and Instrument
Corporation, a corporation of Delaware
Application July 24, 1948, Serial No. 40,594
27 Claims. (01. 178—6.6)
1
This invention relates to machines for pro
ducing screened relief pattern plates and, while
it-is of general application, it is particularly
adapted for producing on a decomposable plate a
2
high speed rotating cutter or chipping or goug
ing tool. With this type of apparatus, the tool
generally leaves small burrs or other irregulari
ties over the face of the plate which seriously
half-tone reproduction of any reproducible image 5 interferes with obtaining satisfactory reproduce
sheet, which plate is suitable for further repro
tions. Furthermore, the metal plates used in’
duction of the image by printing or like duplica
such machines are generally heavy, costly, and
ting processes.
di?icult to ship and are easily damaged by im
. In the reproduction of images, such as photo
proper handling.
graphic prints or negatives by printing or like 10
Furthermore, the automatic machines for
duplicating processes, it has been customary to A
forming such half-tone plates heretofore pro
produce half-tone engravings, that is, engraving
posed have been complex and cumbersome in
plates having a “screen” structure composed of
operation and have been dif?cult to maintain in
a series of regularly spaced dots, by photo-chemi
accurate adjustment, which is necessary to pro
cal processes. In such half-tone plates, the aver
age size and spacing of the dots in each incre
mental portion of theplate vary proportionately
with the average shade value or greyness of the
15 cure half-tone plates of reasonable cost and satis
factory quality.
It is an obJect of the present invention, there
fore, to provide a new and improved machine
for producing screened relief pattern plates
_
corresponding portion of the image. The sur
faces of these dots lie in the original plane of the 20 which obviates one or more of the above-men
plate and receive the printing ink from a roller
tioned disadvantages of the prior-art machines
or the like.
of the type described.
Such half-tone plates and their method of
It is another object of the invention to provide
manufacture are well known in the art, so that
a new and improved machine for producing
- no detailed description is required here. HOW 25 screened relief pattern plates which achieves one
ever, it is also well known that the process of
or more of the following advantageous char
making such photo-engravings involves elaborate
acteristics not hitherto realized: virtual elimina
and expensive equipment and a large number of ’ tion of skill or technique in operation of the
steps, each of which must be performed with
machine; substantial reduction in time required
great care and skill in order to obtain a satisfac 30 to form a plate; ability to form a number of
tory half-tone plate. Such skill is generally
plates simultaneously; extreme accuracy of re
acquired only by extended apprenticeship and
production of all image shades; elimination of all
artisans of the required skill are frequently un
chemical and photo-chemical processes; pre
available. All of the foregoing factors contribute
determination of the desired contrast range, that
to ‘the high cost of such half-tone plates and to
is, range ‘from full white to full black; and a sub
the time required for their completion.
stantial reduction in the weight of the formed _
Heretofore there have been proposed various.
plates.
machines and apparatus for automatically and
In accordance with one feature of the inven
mechanically forming half-tone plates repre
tion, there is provided a machine for producing
sentative of an image to be reproduced. such 40 on a plate from an image sheet a screened relief
machines have generally included a support for
pattern suitable for image reproduction by print
an image sheet, a support for the plate to be
ing processes comprising a ?rst cylinder for sup
formed, and mechanism for scanning the two
porting a plate, a second cylinder for supporting
supports synchronously. The image sheet scan—
an image sheet, and means for rotating the
ner. has‘ included a photoelectric pick-up, the 45 cylinders synchronously. The machine further
output of which is ampli?ed electrically and
comprises a ?rst reciprocable carriage including
utilized to actuate some type of plate-cutting or
an electro-optical pick-up system disposed for
deforming tool carried by the plate scanner. An
scanning an image sheet on the second cylinder,
interrupter is included at some point in the sys
a second reciprocable carriage including a plate
tem' .to produce the screen structure. In one 50 deforming tool disposed for scanning a plate on;
previously proposed arrangement, the plate
the first cylinder, means responsive to the output
deforming tool is in the form of a heated stylus
of the pick-up system for actuating the plate-7
acting on a plate of decomposable material but,
deforming tool, and means for reciprocating the;
in general, such proposed machines have utilized
carriages synchronously. The machine also in-_v
metal plates-and the‘ deforming tool has been a 65 cludes an electrical screen generator including a‘
2,575,546
4
3
rotor element driven synchronously with said
cylinders and an independently rotatable stator,
printing processes. By the term “image sheet,"
and means for rotating said stator at a speed of
a lower order of magnitude than said rotor ele
meant any sheet carrying _an optical representa
ment, the output of said generator being con
nected to modulate the output of said pick-up
photographic positive or negative print, a photo
graphic transparency, either positive or negative,
or the like. By the term “screened relief pat
tern,” as used herein and-intheapp'en‘d'ed claims,
system.
,7
a
.
‘_
n
as used herein and in the appended claims, is
tion of the image to be reproduced, such as a
5
In the preferred'embodiment of the invention,
is meant a pattern in which regularly spaced por
tions of the surface are removed, the area of the
the engraving machine optionally includes other
desirable features, among which are the follow
ing: the electro-optical pick-up system includes
a light source and a source of puisatnigfqgnegc
of screen frequency, such as the ,screenggener
removed portions in any elemental portion of the
print varying with the shade values of the corre
sponding elemental portion of the image to be
ator, connected for modulating such light source;
‘reproduced, the_be'st known example of such
in order to form on the plate an inverted image .A a screened relief ‘pattern being the half-tone
photo-“engraved ‘plate. By the term “printing
of that on the image sheet, the pi‘ckliip'syst'e‘m
processes,” as used herein and in the appended
carriage and the tool carriage are driven by aten
claims, is meant any process by which a plate
sioned inelastic belt, one of the carriages being
carrying a screened relief pattern may be uti
adapted to be locked to one run of the belt and
the other being provided with a releasable clamp , lized to produce multiple reproduced images, of
which the most usual example is the'conventional
to-enga'ge the otherrun of the belt; further, the.
printing process.
tool vcarriage comprises a tool-‘actuating as
The machine of vFig. 1 includes plate andeimage
sembly carrying the ‘plate-deforming tool and
sheet supports, speci?cally,v a cylinder Hlon which
means for biasing theitool' assembly into engage
is supported or secured in any suitable mannera
ment with the plate-cylinder; the tool assembly
plate ll of deformable material ‘and .a "second
cylinder I2 on which is supported or secured :an
also includes an adjus'tahbl'e shoe engaging a
plate on- the plate cylmdervfor vdetermining the
image sheet [3. By the term “deformablerma~
,
terial” is meant a material that ‘may :be cut,
In accordance with another feature er a pre
ferredfo'rm of the inventiom'a machine of the 30 gouged, decomposed or otherwise deformed byan
- engraving tool or stylus tovform an imageeree
type described includes means for adjusting the
neutral position of thetool.
system substantially independentlyto' adjust the
maximum deformation of the “plate, correspond
producing plate. The .plate and vcylinder as
sembly H), Il may be of any suitable type-but
preferably is of the'type-describe'd and claimed
in applicant's copending application, Serial No.
40,595, ?led concurrentlyherewith. The image
sheet I3 for use‘in the machine speci?cally :de
ing to the white level of‘ an image sheet.
scribed hereinafter is :a :photographic positive
output of the "screen. generator to adjust the
minimum deformation of .theépl'ate, correspond
ing to the black level of an ‘image sheet, and
means-foradjusting-the output of the pick-up 35
print.
"Another feature of the-preferred form of the
invention comprises means'for biasing the plate 40 The machine ‘of Fig. 1 includes ‘means-for rotat
ing the cylinders 10 and 12 synchronously and
deforming tool to an inoperative position, a nor
preferably isochronously. Speci?cally, this fro
mally excited electromagnetic’means for retain
tating means includes a-common shaft for the
ing thetool in an operative. position, and means
two cylinders including portions “(1,441) coupled
responsive to the failure ‘of the source of periodic
by a disengageable coupling i5. The coupling l~5
screen potential, such as the screen generator,
includes a notched disc l5arand, a complementary
for actuatingthetool to ‘an inoperative position.
For a better’ understanding of the present in
vention, together withother'andfurther ‘objects
thereof, reference is had to the following descrip
tion taken in connection with the accompanying
drawings, vand its scope will bepointe'd out in the
appended claims.
.
'
‘Referring now to the drawings, Fig. 1 ‘is-a
schematic perspective ‘of ‘a machine for produc
ing ‘on a plate from ‘an image ‘sheet ‘a screened
relief pattern suitable for image reproduction by
printing processes; Fig. 1a is a chart to aid in ex
plahation of the ‘operation of "the ‘machine of Fig.
1; Fig. 2 is a fragmentary view, partly in sec‘
tion,» of therplate-defo'rming tool assembly ofthe
machine of Fig. 1 together with an associated
stroboscopicivie'wer; Figs. 3a and 3b are ‘sche
matic perspective views of the tool-actuating
mechanism in its neutral position and ‘one ex
treme position, respectively; Figs. 4a and 4b are
top plan and longitudinal 'elevational views, re
spectively, of the machine'represented in Fig. 1;
while Fig. 5 is a schematic electrical circuit ‘dia
gram of the various electrical and electronic com
ponents of the machine of Fig. 1.
disc [517 provided with a pin .l'5c_adap_ted accu
‘ rately to engage the notch of disc l5a when these
discs are moved axially by a lever "l5dto effect
engagement of the coupling. This pin-type
coupling ensures engagement'of the two Jshaf-t
portions Ma, Nib in a predetermined phase rela
tionship so that they rotate isochronously. The
shaft Ilia is connected to‘ be ‘driven by a motorlt‘
which may be of anyfsuitable type, althou'ghifa
number of machines are to be operated in 'Pmuli
tiple, as described hereinafter, the motor must
be of the synchronous type. The ‘driv-ingwcon
nection from the motor iii-to the shaft Mar-in:
cludes a ?exible ‘coupling ll ofranysuitabl'e type
which mechanically ?lters or smoothesaout ‘any
pulsation characteristic ‘of the ‘driving. motor 16.
This driving connection further includes a'worm
i8 and engaging worm‘ gear l9 vvand anovér=run=~
ning or one-way drive‘clutchi?, ‘the driving ele
ment of vwhich is connected to gear [9 'an‘d:the
driven element of 'whichisconnected-to shaft'l‘da.
On the drive shaft kid is aheavy‘?'y "wheel ‘21
which ensures pulsationless rotation'of 'theisha'ft
70 Ma, léb and the cylinders I'O'an'd l'2‘regar'dless
of irregularities which :might otherwise ‘result
from the characteristics of the motor icon-lin
drawings, there is illustrated ‘schematically a
perfecti'ons 'in the ‘drivingsgears. The overertnr-v
machine ‘embodying the invention for produc
Referring now more particularly to Fig. l'of the ,
ning clutch 2B, which-may‘be'of'anyconventional
ing on‘ a ‘plate ‘from ‘an image sheet‘ a screened
rcllefpattern suitable for 'imagereproduction by ' type, 'serves two purposes: ('1) itallows'l‘the??y
5
2,575,548f
wheel 2| to decelerate normally upon de-cner
glzation of the driving motor I6 without impos
ing an undue back load on the speed-reducing
gears 18,19 and (2) it permits manual rotation
of the cylinders ill and i2 during mounting of the
respective plate ii and image sheet l3 thereon,
free of the driving gearing.
The machine of Fig. 1 also includes means,
such as a reciprocable carriage 22 including an
electro-optical system, for scanning an image
sheet l3 on its supporting cylinder [2. The elec
tro-optical scanning system is shown schemati
cally as including a light source 22a having an
_.-; The tool-actuatingv assembly-30 also includes
means for biasing the tool to an inoperative posi
tion.~ To this end, the assembly 30 is mounted
on a platform 34 which is pivoted on the carriage
23 as by a pivot pin 35. About the pivot pin 35
is secured a stiff helical biasing spring 36 with
extending portions acting on the platform 34 and
carriage 23 to bias the carriage 33 for pivotal
movement in a clockwise direction about the
pivotpin 35. Secured to the under side of the
carriage 23 is an electromagnet 31, for which the
pivoted platform 34 acts as an armature. As de
scribed hereinafter in connection with the circuit
diagram of Fig. 5, the electromagnet 31 is nor
mally excited to attract the platform 34 and re
tainthe shoe 32 and the tool 24 in an operative
relation with respect to the cylinder [0 and plate
only diifused re?ection, that is, the angle of
I l. The tool-actuating assembly 30 also includes
incidence of the axis of optical system 22b at the
electromagnetic means connected to respond to
image sheet i3 is not the same as the angle of 20 the output of the electro-optical pick-up system
re?ection of the axis of the optical system 2211.
22a-22d for actuating the tool 24. This electro
The machine further includes means, such as a
magnetic actuating means is shown more clearly
reciprocable carriage 23 including a plate-de
in Figs. 3a and 3b, while its connection to the
forming tool 24, for scanning a plate H on its
electro-optical pick-up system is described here
supporting cylinder ill. By the term “plate-de 2: inafter with reference to the complete circuit
forming tool,” as used herein and in the appended
diagram of Fig. 5.
optical system 221) and a photocell 220 provided
with an optical system 22d including an aperture
stop to limit its ?eld of view to an elemental area
of the image sheet i3 and is disposed to receive
claims, is meant a tool capable of deforming a
The machine of Fig. 1 further includes a source
plate II as by cutting, gouging, indenting, there
of periodic pulsating potential or current, spe
mally decomposing, or the like. In the preferred
ci?cally, an electrical screen generator 40 driven
embodiment of the invention, the tool 24 is a
synchronously with the cylinders 10 and I2 and
heated stylus for thermally decomposing incre 3 Q. connected to modulate the output of the pick-up
mental areas of the surface of the plate II, as
described hereinafter. The carriages 22 and 23
reciprocate on parallel longitudinal guide rods 38
and 39.
There is further provided a mechanism for
reciprocating the carriages 22 and 23 in opposite
directions to form a laterally inverted screen
system 22a—22d for producing a pulsating ex
citation of the actuating means 30 at a screen
frequency.
Speci?cally, the generator 40 in
cludes a toothed rotor element 40a, mounted on
and driven by the shaft 14a, thus eliminating
any-back-lash in the drive of the screen genera~
tor and ensuring absolute accuracy in the spac
ing of the screen dots. The generator also in
relief pattern on plate li. This mechanism in
cludes a pair of spaced pulleys 25 and 26 and a
is cludes. an independently rotatable toothed stator
tensioned inelastic belt, such as a steel tape 21,
element 401). The teeth of the elements 40a and
supported on the pulleys. Tensioning of the tape
40b are equally spaced about the outer and inner
21 is effected by a stiff helical spring 28 joining
peripheries thereof, respectively, the number of
its two ends. The pulley 25 is driven from shaft
teeth in each being determined by the desired
[4a through double worm gearing 46, 41 and
48, 49, the gear ratio being preferably so chosen} 45 “screen.” For example, if a 12G-screen plate is
desired, each of the elements 40a and 40b will
that the pulley 25 makes one revolution for the
have 120/\/2 teeth within an angle of rotation
complete normal range of travel of the carriages
corresponding to a peripheral travel of the stylus
22 and 23. One of the carriages, preferably the
24 of one inch on the plate i i. The elements 40a
carriage 23, is adapted to be locked or secured
(by means not shown) to the lower run of the 50 and 40b are electrically insulated from each other
tape 21, while the other carriage 22 is provided
with a releasable clamp disposed to engage the
and are connected in an electrical circuit to form
the two elements of a condenser, as described
hereinafter in connection with the complete elec
upper run of the tape 27 and including a man
trical'system of the machine.
ually operable element or knob 29, by which the
carriage 22 can be released from the tape 2‘! to 55 . There is also provided means for rotating the
permit adjustment of the carriage 22 independent
stator element 401) at a speed of a lower order of
magnitude than the rotor element. Speci?cally,
of the carriage 23 upon disengagement of the pin
there is provided a speed-reducing means between
coupling 15. This adjustment is provided to
the shaftv Ma and stator element 431). This means
permit accurate registration of the electro-optical
system of the carriage 22 with an image sheet 60 includes a pulley 41 mounted on a shaft 42 sup
porting the stator element 3%. Driving the pul
l3 on the cylinder i2 when initially setting up the
ley 4 l- is an endless belt 43 passing around a pair
machine.
The carriage 23 includes a tool-actuating as
of guide pulleys 44 and a return pulley 45 dis
sembly 3G for driving the plate-deforming tool
posed so that the upper run of the belt 43 is
24. As shown in Fig. 2, the assembly 30 includes 65 parallel with the path of movement of the car
means for determining its neutral position with
riagez23. The belt 43 is connected to be driven
respect to the plate H on the cylinder ill. This
by the carriage 23 as by a connection 43a, as
means is in the form of a resilient hairpin 3!
shown, and includes a tensioning spring 46 on
having one arm secured to the assembly 30 and
the return side of its connection 43a. Adjust
carrying at the end of the other arm a shoe 32 70 ment of the speed ratio may be determined by
disposed to engage a plate I l on the cylinder Ill.
selection ‘of the diameter of pulley 4! relative
The separation of the arms of the hairpin 31 may
to the lead of the carriage 23. The overall re
be adjusted to adjust the neutral position of the
duction is such that the speed of the stator ele
shoe 32 by means of a thumb nut 33 threaded in
ment 40b is a small fraction of the speed of the
the other arm of the hairpin 3|.
15 cylinders wand l2. If a plate is desired in which
23,575,846“
7.
8
the angle oi.’ the screen lines v‘is 45". as iscus
tom'ary, the speed of the stator element '40!) is
that Jfraction of the speed of- the-cylinders “land
12 such that the stator 40b rotates an angular
distance equal torone tooth and space during the
time that the cylinders l0 and I2 ‘makeitwo com
plete revolutions.
I
.The details of construction vof-lthe stylus actu
ating mechanism 30 are best shown in'th'e 'sche
matic perspective views, partly inisection,>of Figs.
3a and 32). As shown, th‘e'magne'tic circuit of iéthe
mechanism-30 is formed by two spaced opposed
C-magne'ts 30a and Y391). symmetricallyldi'sposed
in the air gaps formed between the opposed legs
of the C-‘ma'g'nets 30a. and 30b is a vane-like mag
netic armature 36c about either endfo'f Whichlare
disposed the actuating windings 30c and 3011,
thus providing a balanced electromagnetic actu
ating'mechanism.
'
upon an elemental area of the plate ll being
examined. The lamp '65 is-connected to a cir
cuit for exciting it from the periodic source or
screen generator 453, as described hereinafter.
Referring now to'Fig. 5 of the drawings, there
CI
is represented a circuit diagram, partially sche
matic, of the electrical system of the apparatus of
Fig. 1, corresponding elements being identi?ed
by'the same reference characters. Starting with
10 the pick-up photocell 220, this is represented as
a ‘device of the conventional electron multiplier
type, in which the several multiplier cathodes
229 are connected to electrically spaced points on
a voltage-divider resistor ‘55 connected between
ground and the negative terminal of a unidirec-v'
tional source
connected to
loadresistor
plied by way
-—B. The anode of the cell 22c is
a suitable source +13 through a
‘H, the signal across which ‘is ap
of a coupling condenser l2 to the
In Fig. 3a the armature 30a is shown in the 20 input terminals of a photocell ampli?er 13,
unexcited or neutral position, while 'inlFig. 31) it
which may be of any suitable well-known type.
is 'shown in one limiting actuating position cor
The output terminals of the ampli?er ‘T3 are
responding to maximum excitation of 1the wind~
connected to supply the ampli?ed signal across
ings 30c and GM of one polarity.
extension
a load resistor
A low-pass inverse-feed-back
of armature 35a is connected ‘to the stylus 24 '- network l5, constituted for example by a series
which is loosely supported for reciprocation in a
resistor 15a followed by a shunt condenser 15b,
projection '30:!‘ of the casing 39. Surrounding-the
is connected from the output terminals of the
stylus 24 is a noninductive heater 56 connected
ampli?er '73 through a coupling condenser ‘it to
to/and supported by terminals .51. 'Theccasing of
the input terminals thereof for eliminating the
thevmechanism '38 comprises a permanent mag 30 effect on the output signal of variations of the
net'structure in which the side plates-130f and 30g
mean brightness of an image sheet on the mean
are permanent ‘magnet elements, while the end
position of the stylus 2/12. As well understood in
plates complete their magnetic circuit through
the C-members 30a and 38b. The armature ‘30c
is mounted on a tension shaft 36h, rigidly sup
ported ‘from the casing. In Figs. 3a and ‘3b the
dotted lines indicate the-paths of the permanent
magnet f?ux in the two positions of ‘thea'rmature
member, while the dash lines representthe paths
of ?ux due to the actuating windings 30b and'3llc.
The actual physical construction of ‘one ‘em
bodiment of the apparatus represented :in Figs.
the ‘art, such an inverse or negative feedback
of the low frequencies reduces the gain of the
ampli?er at such frequency to a very small value
without appreciably affecting its response to the
high-frequency components of the signal gen
erated by the photocell 220.
The periodic source of generator 40 is con
nected to modulate the output signal of the pick
up system developed across the load resistor 14.
1 and 2 is shown in Figs. 4a. and 4b in which cor
responding‘ elements are identi?ed ‘by the same
reference characters. Brie?y, ‘the whole appa
ratus is mounted'on a base or bed plate so, the
To this end, the generator 5i] is connected as a
variable condenser in the input circuit of a screen
ampli?er unit ‘ii; speci?cally, the rotor is con
nected to ground while the stator is connected to
a source of polarizing voltage +B through an
gearing l8, l9 and cent, the pulley '25, the fly
isolating resistor ltd. The output of amplifier
wheel 2i, and the screen generator iii) being ren
llis coupled through a condenser 18 to an addi
closed within an end housing 5i .
tional ampli?er unit ‘39, the output of the ampli
The actuating
mechanism 383 is enclosed within a housing .52
?er 19 being connected through a coupling con
mounted on carriage 25, while theelectro-op'tical
denser Bil to a load resistor 8| provided with an
pick-up system is disposed within a housing :53
adjustable tap or connection-82. The signal at.
mounted on carriage 22. The-pin clutch, ‘1.5 is
the tap 82 is applied to a scanner light ampli
fier 84, which is power amplifier for generating
disposed within a central bearing support 154
which includes the pin clutch l5 and-its operating 55 a periodic current synchronous with the periodic
potential developed by the generator Ail. The
lever Had. The unit 54 also includes electrical
current output of the ampli?er 84 is connected to
switches and control members for the ‘electrical
system of the machine described hereinafter.
modulate the light source 22a of the pick-up sys
The pulley 25 and the bearing for the right-hand
tem; speci?cally, the lamp 22a may be connected
end of the shaft lrlb are disposed in an .end 60 directly in the output circuit of the amplifier 84
to be excited thereby.
housing 55. It will be understood, however, that
the details of this mechanical construction and
A second load resistor 85 is included in ‘the
arrangement may be varied within wide limits
outputcircuit of ampli?er l9 and provided with
to suit individual special requirements.
an adjustable tap 86 from which a selected por
Referring speci?cally to Fig. 2 of the drawings,
tion of theoutput signal is applied to a strobe
there is shown associated with the cylinder in
light. ampli?er 8?, which is also a power ampli?er
and plate It a stroboscopic viewer forzinspecting
ford'eveloping a periodic current pulse synchro
a plate while it is undergoing deformation. This
nous with the periodic potential generated by
generator #9. ' The gaseous discharge lamp 65
viewer includes a portable microscope 60- dis
posed on a support iii adjustably pivoted ‘at 62
of vthe stroboscopic vieweris connected directly
on a base $3 and thus adjustable for focusing-on
a plate H. The microscope ?ll is included within
an enclosing housing: 64 which also includes a
stroboscopic light source, suchas a gaseons‘lamp
in the output of the ampli?er 8i.
-
Inorder to permit a ready adjustment of th
maximum and minimum penetrations of a plate '
l i ‘being deformed by the stylus 213 in accordance
65and an optical system'??ifor iocusi-ng'the light *78 'with the maximum and minimum shadevalues':
2,575,546
of the image being reproduced, there is provided
a circuit for combining an adjustable portion of
the output of the screen generator 40 with an
adjustable portion of the output from the photo
cell 220 to energize the actuating mechanism 30.
To this end, the output of the ampli?er TI is ap
plied also through a coupling condenser 88 to a
load resistor 89 having an adjustable tap 90.
The load resistor ‘I4 of the ampli?er ‘I3 has an
adjustable tap 9I and the taps 90 and BI are
interconnected through isolating resistors 92 and
93 and a switch I05, the junction of resistors 92
and 93 being connected to an isolating ampli?er
94 which, in turn, is connected to a power ampli
10
tacts I I9 of a relay I 20. The relay I 20 is con
nected in the anode circuit of a vacuum-tube
ampli?er I2I, the control electrode of which is
connected to the output circuit of ampli?er ‘l9
and includes a conventional grid leak I22 and grid
condenser I23. The relay I20 and ampli?er I2I
are adjusted so that the relay I20 maintains its
contacts closed whenever normal potential is sup
plied from the screen generator 40 through the
ampli?ers ‘I1 and 19. Thus, the elements I20,
I2! constitute means responsive to the failure
of the source, speci?cally, to the failure of rota
tion of the generator 40, for interrupting the con
‘trol circuit II2, which de-energizes holding
?er 95, the output of which is connected through 15 magnet 31, permitting the biasing spring 36 to
a power transformer 96 to the serially connected
actuate the tool 24 to inoperative position.
windings 30c and 30d of the stylus actuating
The contacts I I9 of relay I20 complete a circuit
mechanism 30. In case it should be desired to
to the holding magnet 31 of the actuating mech
operate the machine of the invention from a sep
anism 30 through a resistor I24 and a rectifying
arate synchronized source of image signals from 20 device such as a contact recti?er I25, the wind
a local or remote source, there may be provided
ing 31 being by-passed by a condenser I26. Con
a voltage divider I03 having an adjustable tap
nected between the buses I I I and I I2, immediate
I04 and connected to the source or supply ter
ly following the oif-on switch I I3, is a current
minal I06 at which such signals appear. The
transformer I21, the primary winding of which
switch I05 may then be operated selectively to 25 is connected in series with a constant-current
connect with the tap I04 or the tap 9|.
ballast tube I28. The secondary winding of trans
In series with the windings 30c, 30d is a drop
former I2? is connected directly to the heater 56.
ping resistor 91 having an adjustable tap 98,
Following the contacts II6 of the safety switch,
while across the secondary winding of transformer
the motor I6 is connected between the buses III
96 is connected a voltage-divider resistor 99 hav
30 and I I 2. While the motor I 6 may be of any suit‘
ing an adjustable tap I00. The taps 98 and I00
able type, it is shown as a split-phase condenser
are interconnected through isolating resistors
motor of the hysteresis synchronous type, having
WI and I02, the junction of which is connected
one winding IBa connected directly between the
back to the input circuit of the power ampli?er
power buses and a second winding IBb connected
95. From the tap I00 is derived a signal potential 35 therebetween through a phase-splitting con
which varies with, and is a fraction of, the
denser I29. At this same point, a power recti?er
potential across the actuating windings 30c, 30d,
unit I30 is connected between the buses III and
while from the tap 98 is derived a potential vary
H2. The unit I 30 may be of any conventional
ing with the signal current through the windings.
type for converting the alternating-current sup
These two signals are combined and fed back
ply to a unidirectional current of required oper
to the input circuit of ampli?er 95 as an inverse
feedback for linearizing the overall character
istics of the ampli?er 95 and actuating mech
ating potentials, indicated collectively by the
reference +B.
Coming now to the operation of the apparatus
described and referring ?rst to the mechanical
impedance of ampli?er 95 to obtain a desired 45 operation of the apparatus of Fig. 1, it will be
degree of damping of the actuating mechanism
seen that initially a plate to be engraved or de
30. The unidirectional sources for the several
formed is mounted’ on cylinder I 0 in any con
ampli?er units of the circuit of Fig. 5 are repre
venient manner, as by the method described in
sented collectively as +B, although the sources of
applicant's aforesaid copending application, Se
the several ampli?ers may be of different potential 50 rial No. 40,595. The pin clutch I5 is disengaged
values according to the tube types and circuit
and the image sheet is then mounted on cylinder
constants of each ampli?er. It will be under
I2 in any suitable manner. For this purpose, the
stood that each of the several ampli?ers de
carriage 22 may be unclamped from the belt 21
scribed may be of any suitable conventional type
by means of the release knob 29. The carriage
of one or more stages, as required.
55 22 may then be adjusted longitudinally to obtain
The general electrical power circuit for the
proper registration , of the pick-up system
system is represented at the top of Fig. 5. Power
22a—22c with the image sheet. The pin clutch I5
for the unit as a whole may be conventional
is then engaged to ensure a direct driving connec-4
60-cycle, l10-volt power applied to the input ter~
tion between the shaft portions I 4.41 and I4?) and
minals H0. The lower terminal I I0 is connected 60 further to ensure correct phasing of the cylinders
to a bus III common to the power and control
I 0 and I 2.
mechanisms hereinafter described. The upper
The cylinders I0 and I2 may be manually ro
terminal I I0 is connected to a control line II2
tated by virtue of the slip clutch 20 and the
through a manually operable off-on switch H3;
mechanism may be operated until the stylus 24
9. pair of limit switches I I4 and H5 disposed in 65 registers with a margin of the plate to be en
the path of travel of carriages 22 and 23 (not
graved. The stroboscopic viewer shown in Fig. 2
shown) for interrupting the electrical circuit
is then disposed to obtain a microscopic view of
in case either carriage reaches its limit of travel;
the elemental area of the plate II in registry
the normally open contacts I I 6 of a safety micro
with the stylus 24 and, with the electro-optical
switch mounted on the platform 34 and adapted 70 system in operation as described hereinafter, the
to be closed initially by manual operation of the
deforming or decomposing of the plate II by the
tool-actuating assembly 30 to operative position
stylus 24 is observed when the electro-optical
to complete a holding circuit for electromagnet
pick-up system views the darkest and lightest
31; normally closed contacts of a push button
portions of the image sheet to be reproduced.
stop switch I I8; and the normally closed con 75 Adjustments of the electrical system are then
anism 30 and for effectively controlling the output
2,575,546
i2
I 1’
40 is‘so proportioned to the constantsof' thev‘actu
ating means 39 that the following relationships
made, as described hereinafter, to obtain the ap
propriate minimum and maximum penetrations
of the plate H‘ by the stylus 24 corresponding to
the darkest and lightest shade values present in
are
satis?ed:
I
-
'
-
(1) The mean penetration of the plate H
‘the image sheet, respectively.
,
C1 by the tool 2A; is of the same order of magnitude
as the neutral separation of the tool and the
The cylinders It and F2 and their associated
plate.
‘mechanism are then operated manually to place
the eIectro-optical pick-up system at the starting
corner of the image to be reproduced. The elec
trical system is then put in operation and is ef
fective automatically to cause the electro-optical
pick-up system 'to scan the image sheet in a
‘spiral path and simultaneously to cause the stylus
24 to scan the’plate II. While the cylinders H}
I
(2) The amplitude of the pulsating excitation
from the screen generator it is so proportioned
to the response of the electro-optical pick-up
system that the minimum penetration of the tool,
corresponding to one shade extreme in the image,
for example, black, is of the order of 1/5 of its
maximum penetration, corresponding to. the
and l2' are effectively on. a common shaft, so
other shade value, for example, white.
that they rotate isochronously in the same di
rection, the carriages "22 ‘and 23 move at equal
(3) The rotational spee'd‘of the cylinders l6
and I2 is so related to the frequency of excita
tion from the screen generator 46 that the pee
ripheral travel of the plate cylinder it during
one period of the screen-frequency excitation‘ is
approximately twice the line spacing. For ex
ample, if it is desired to produce a 120-line half—
tone plate, the cylinder iii should travel 1/ 60\/2
inch during one period or cycle of the screen
speeds ‘in opposite directions, due to the fact that
they are clamped to opposite runs of the tape 21,
as described above. The result is that the image
reproduced on the plate H is laterally inverted
withv respect to the image sheet, so that when
it visv turned over it will reproduce the image in
its correct relation.
-
>
Rotating simultaneously with the cylinders H1
25
and I2 and‘ at the same speed is the rotor element
46a‘ of the screen generator 45. This generator,
as described hereinafter, is effective to modulate
the light source 22c of=the electro-optical sys
tem and the constants of the system are selected
so as? to procure substantially complete modula
tion, that is, so that the‘ light source 220. is sub
stantially completely‘ extinguished at the fre-'
quency of the screen "generator. The output of
the'photocell 220 is thus likewise modulated‘ and,
after ampli?cation and the suppression of the
unidirectional component, is applied as a signal
modulated'carrierwave to thel'windings 36c and
30d of. the actuating mechanism’ 30. This excita
tion‘of the windings 30c and 30d causes the stylus .
to oscillate about‘its "mean or neutral position at
the frequency of the signal developed by the
vscreen‘ generator All, while the amplitude of the
‘oscillation is varied or modulated in accordance
withgthe amplitude of the signal developed by
' '
frequency.
v
The foregoing relationships are represented in
Fig. 1a, in which the line b represents the devele
opment of the surface of plate I 1, while the line ('1.
represents the relative path of travel of the '
neutral position of the tool 24.
In this figure,
curve 0 represents one cycle of screen frequency
modulated to minimum amplitude corresponding
to a black shade in the image being-scanned,
while curve (1 represents another cycle of the
screen frequency modulated at maximum ampli
tude corresponding to a white portion of the pic
ture being scanned. The relative dimensions of
the various parameters of one machine embody;
ing the invention are represented in Fig. 1a and
it will be seen that these relative dimensions sat
isfy the ?rst two of the foregoing relations; that
is, the excursion of curve 0 below the line b, rep
resenting the minimum penetration of the
stylus, is approximately
one-?fth
the ex‘
- cursion of curve (1 below line 1), represent
‘the photocell 226' which, in turn, varies with the
ing the maximum penetration of the stylus,
shade- values in the successive incremental areas
while the mean value of these two excursions is
of the same order of magnitude as the separation
of the lines a and b representing the neutral separation of the stylus and the plate. It will also
be seen that, since the unidirectional component
of the modulated signal is suppressed so that only
a pure alternating current signal is applied to
of the image sheet being scanned. As stated
vabove, the‘ plate If is preferably of a decom
posable material, such' as cellulose nitrate, while r
the stylus 24 is heated to a temperature of the
order of 1200-” F. by the heater 55 so that, as it
‘oscillates into contact with the plate H, the
stylus removes portions of the plate by thermal
decomposition; forming pits of depth and sur
face. area- varying with the amplitude of the os
cillation of‘ the stylus 24" and‘thus with the varia
tions in the shade value of the image sheet. As
jaresult, there is formed on the surface of the
plate H the equivalent of a half-tone structure
comprising a series of elemental dots separating
gieries of. pitsv formed by the oscillating stylus
. vF'or proper image reproduction, the screen
structure of the plate II should, for the lightest
shade presented in the image being reproduced,
contain a complete series of dots or islands sep
arating the pits but of minimum area. Con—
versely, when scanning the‘ darkest portion of
the image sheet, a complete series of pits of
the windings of the actuating mechanism 3t, only
' the negative half of each cycle of screen frequency
is effective to actuate the tool 24 into penetration
of the plate H. Therefore, the surface of plate‘
1 I on cylinder ill must travel a distance equal
to the spacing of adjacent lines in the‘ period
from the commencement of one negative half
cycle effective to form a pit of one line to the
successive negative half cycle effective to form
the next pit. This satis?es the third relation
ship above.
Turning now to Fig. 5 of the drawings, there
will be taken up the operation of the electrical
system of the machine of Fig. 1. In order to
place the machine in operation, the on-off switch
H3 is initially closed. This energizes the heater
56 through the current transformer l2? and the
heaters of the various electron ‘tubes. With the
limit switches H4, H5 normally closed and after
a reasonable warm-up time, the tool actuating
minimum surface area should be formed. In
order to secure this result, certain adjustments
of the ‘electrical system are made, as described
hereinafter, to ensure that the amplitude of the
assembly 30 is manually lowered to operative
pulsating excitation from the screen generator
position. contacts H6 are closed, and the motor
2,675,546
14
I6 is placed in operation to drive the various
mechanical elements of the machine of Fig. 1,
including the screen generator 4%. Simultaneous
following speci?cations of one machine con
structed in accordance with the invention and
providing satisfactory operation:
ly, the power recti?er I30 is energized and sup
plies at its output terminals +B suitable uni
directional potentials for the several ampli?ers
of the system. When the apparatus has reached
normal speed and the power recti?er is in opera
tion, the screen generator 40 is effective to de
velop a periodic potential of the desired frequency
which is ampli?ed in the units 11 and ‘I9 and ap
plied to the grid of ampli?er tube l2l. Initially
tube I2! has zero bias and is fully conductive,
energizing relay I20 to hold open its normally
closed contacts. However, when the screen-fre
quency signal is applied to the grid of tube I 2|,
it is self-biased by grid recti?cation substantially
to cut-off de-energizing relay I20 to close its
contacts H9. Up to this time, the platform 34
must be held down manually. Upon the closing of
contacts H5 and H9, however, the electromag
net 37 is energized with unidirectional current
through the recti?er I25. The electromagnet
then attracts its armature 34 to hold the actuat
ing mechanism into engagement with the plate
Screen _______________ __ 65 lines per inch
Screen frequency _____ __ 350 cycles per second
Speed of cylinders Ill, I2 . 50 R. P. M.
Lead _________________ _. l/65\/§
Mesh
________________ l- 65V?
Stylus 24 _____________ _. Radial to cylinder
Stylus taper angle _____ _. 75°
Thus, there is provided by the invention a ma
chine for producing on a plate a screened relief
pattern from an image sheet which virtually
eliminates all skill or technique previously re
quired to produce half -tone engravings. Further
more, the machine of the invention produces
such plates in only a small fraction of the time
required for conventional photo-engravings. For
example, it has been found possible to produce
a plate 8 x 10" of 65 screen in eighteen minutes.
The machine is capable of extreme accuracy of
reproduction of intermediate shade values be
tween full black and full white. At the same
time, all chemicals and necessary facilities for
H on cylinder I 0. The machine is now in full
handling them are eliminated. By the use of the
operation for forming an image on the plate H.
stroboscopic viewer as described, it is possible to
As stated above, initially the tool 24 is op
determine in advance the desired contrast range
erated to a margin of the plate H for forming
a test pattern on such margin, while observed by 30 of the resultant plate. This is in marked con
trast to the conventional chemical processes
the stroboscopic viewer, as shown in Fig. 2. The
which generally require repeated trials before the
neutral position of the tool 24 is adjusted by ad
desired contrast range is obtained. Further, by
justing the shoe 32 by the knob 33 (Fig. 2) to the
the simple operation of switch Hi5 of Fig. 5, it
desired relation, as represented in Fig. la. In
is possible to adapt the machine of the invention
view of the fact that the output of the screen
to operation from image-representing signals re
generator 40 as ampli?ed in units ‘H, 19, and 81
ceived by radio or wire from remote synchro
is applied to the gaseous discharge lamp 65 of the
nously scanned sources.
stroboscopic viewer, this lamp illuminates in syn
While there has been described what is at pres
chronism with the lamp 22a of the electro-opti
cal pick-up system, so that the elemental portion 40 ent considered to be the preferred embodiment of
the invention, it will be obvious to those_skilled
of the plate ll being viewed is illuminated only
in the art that various changes and modi?cations
for brief intervals synchronous with the peaks of
may be made therein without departing from the
the modulated screen frequency, this is, with the
invention, and it is, therefore, aimed in the ap
points of maximum penetration of the tool 24.
pended claims to cover all such changes and
As is well understood in the art, the observer
modi?cations as fall within the true spirit and
thus obtains an apparently stationary view of
scope of the invention.
the minute portion of the plate penetrated by the
What is claimed is:
tool 24.
1. A machine for producing on a plate from an
Initially the minimum penetration or defor
mation of the plate is adjusted to correspond to ” image sheet a screened relief pattern suitable for
image reproduction by printing processes com
the black level or darkest shade in the image
prising: a ?rst cylinder for supporting a plate;
sheet being scanned. This initial adjustment is
a second cylinder for supporting an image sheet;
made by tap 99 of voltage divider 39 which ad
means for rotating said cylinders synchronously;
justs the minimum amplitude of the screen-fre
quency signal ampli?ed and applied to the actu 55 a ?rst reciprocable carriage including an electro
optical pick-up system disposed for scanning an
ating mechanism 35. This adjustment may be
image sheet on said second cylinder; a second
made substantially independently of the signal
from the electro-optical pick-up system, since
reciprocable carriage including a plate-deform
ing tool disposed for scanning a plate on said ?rst
able fraction of the amplitude of the signal from 60 cylinder; means responsive to the output of said
pick-up system for actuating said tool; means
the screen generator 4!].
for reciprocating said carriages synchronously;
The pick-up system is then adjusted to a por
an electrical screen generator including a rotor
tion of the image of maximum brightness, for
element driven synchronously with said cylinders
example, white, and the tap SI of the voltage
divider ‘M in the output of the ampli?er 73 is then 65 and an independently rotatable stator; and
means for rotating said stator at a speed of a
adjusted to obtain the desired maximum pene
lower order of magnitude than said rotor ele-_
tration in accordance with the relationships of
ment; the output of said generator being con
Fig. 1a. The operation of the system with the
nected to modulate the output of said pick-up
switch Hi5 connected to the external source of
image signals N16 is in all respects the same, it 70 system.
2. A machine for producing on a plate from an
only being necesary that such signals be derived
image sheet a screened relief pattern suitable
from a pick-up system, either local or remote,
for image reproduction by printing processes
operating synchronously with the pick-up car
comprising: a ?rst cylinder for supporting a
riage 22 of Fig. 1.
By way of example only, there may be given the 75 plate; a second cylinder for supporting an image
that signal for black shade levels is an inappreci
15
259255546
is
sheet; ‘means for rotating said cylinders; a ?rst
reciprocable carriage including an electro-optical
pick-up system disposed for scanning an image
sheet on said second cylinder; a second recip
rocable carriage including a plate-deforming tool
disposed for scanning a plate on said ?rst cylin
der; means responsive to the output of said pick
up system for actuating said tool; means for
reciprocating said carriages synchronously; . an
electrical screen generator including a rotor ele- ‘
nected to modulate the excitation of said lamp
synchronously with the scanning of the image
sheet.
6. A machine for producing on a plate from an
image sheet a screened relief pattern suitable
for image reproduction by printing processes
comprising: a ?rst cylinder for supporting ‘a
plate; a second cylinder for supporting an image
sheet; means for rotating said cylinders syn
chronously; a ?rst reciprocable carriage includ
ment driven synchronously with said cylinders
and an independently rotatable stator; and
means for rotating said stator at a fraction of
ing an electro-optical pick-up system disposed
system.
synchronously; said pick-up system including a
light source; a periodic potential generator of
for scanning an image sheet on said second cylin
der; a second reciprocable carriage including a
the speed of said cylinders equal to oneéhalf the
plate-deforming tool disposed for scanning a
ratio of the speed of said cylinders to the screen 15 plate on said ?rst cylinder; means responsive to
frequency; the output of said generator being
the output of said pick-up system for actuating
connected to modulate the output of said pick-up
said tool; means for reciprocating said carriages
3. A machine for producing on a plate from an
image sheet a screened relief pattern suitable
for image reproduction by printing processes
comprising: a ?rst cylinder for supporting a
plate; av second cylinder for supporting an image
Sheet; means for rotating said cylinders iso
chronously; a ?rst reciprocable carriage includ
ing an electro-optical pick-up system disposed
for scanning an image sheet on said second cylinj
der; a second reciprocable carriage including a
plate-deforming tool disposed for scanning a
plate on said ?rst cylinder; means responsive to
the output of said pick-up system for actuating
said tool; means for reciprocating said carriages
isoohronously; an electrical screen generator in
cluding a rotor element driven directly by said
screen frequency; and a power ampli?er for gen
erating a periodic current synchronous with said
periodic potential and connected to modulate
said light source synchronously with the scan
ning of the image sheet.
7. A machine for producing on a plate from
an image sheet a screened relief pattern suitable
.ior - image reproduction by printing processes
comprising: a ?rst cylinder for supporting a
plate; a second cylinder for supporting an image
sheet; means for rotating said cylinders syn
chronously; a ?rst reciprocable carriage includ
ing an electro-optical pick-up system disposed
for scanning an image sheet on said second cylin
der; a second reciprocable carriage including a
shaft and a rotatable stator element; and a
plate-deforming tool disposed for scanning a
speed-reducing gear connected to
plate on said ?rst cylinder; means responsive
drive ' said
stator from said shaft; the output of said gen
erator being connected to modulate the output of
said pick-up system.
4. A machine for producing on a plate from .'
to the output of said pick-up system for actuat
ing said tool; means for reciprocating said car
riages synchronously; said pick-up system including a gaseous electrical discharge lamp; a
sheet; means for rotating said cylinders syn- -
periodic potential generator of screen frequency;
and 'a power ampli?er for generating a periodic
current synchronous with said periodic poten—
tial and connected to excite said lamp syn
chronously with the scanning of the image sheet.
chronously; a ?rst reciprocable carriage includ
'- .8. In a machine for producing on a plate from
an image sheet a screened relief pattern "suitable
for image reproduction by printing processes
comprising: a ?rst cylinder for supporting‘ a
plate; a second cylinder for supporting an image
ing an electro-optical pick-up system disposed
an image sheet a relief pattern suitable for image
for scanning an image sheet on said second
reproduction by printing processes and including
a pair of synchronously rotatable cylinders for in
dividually supporting a plate and an image sheet
and a pair of reciprocable carriages individually
cylinder; a second reciprocable carriage includ
ing a plate-deforming tool disposedfor scanning
a plate on said ?rst cylinder; means responsive
to the output of said pick-up system for actuating
said tool; means for reciprocating said carriages
synchronously; said pick-up system including a
including a pick-up system and a plate-deform~
ing tool for respectively scanning said image
sheet cylinder and said plate cylinder, a mecha
light source; and a-source of pulsating current of 55 nism for reciprocating said carriages synchro
screen frequency connected to modulate .said
nously in opposite directions to obtain an in
light source synchronously with the scanning of
verted relief pattern comprising: a pair of spaced
the image sheet.
'
"
' '
pulleys; a tensioned inelastic belt-supported on
5. A machine for producing on a plate from an
said pulleys; one of said carriages including
image sheet a screened relief pattern suitable 60 means for looking it to one run of said belt and
for image reproduction by printing vprocesses
a releasable clamp on the other of said carriages
comprising: a ?rst cylinder for supporting'a
disposed to engage the other run of said belt.
plate; a second cylinder for supporting an image
9. In a machine for producing on a plate from
sheet; means for rotating said cylinders-syn;
an image sheet a relief pattern suitable for image
chronously; a ?rst reciprocable carriage includ 65 reproduction by printing processes and including
ing an electro-optical pick-up system disposed
, for scanning an image sheet on said second cylin
a pair of synchronously rotatable cylinders for
individually supporting a plate and an image
sheet and a pair of reciprocable carriages in
dividually including a pick-up system and a plate
der; a second reciprocable carriage including a
plate-deforming tool disposed for scanning a
plate on said ?rst cylinder; means responsive to 70 deforming tool for respectively scanning said
the output of said pick-up system for "actuating
image-sheet cylinder and said plate cylinder, a
said tool; means for reciprocating said carriages
mechanism for reciprocating said carriages syn
synchronously; said pick-up system including a
chronously in opposite directions to. obtain an
gaseous electrical discharge lamp;- and‘ a source
inverted relief pattern comprising: ‘a pair of
of- pulsatingl'current. ofscreen frequency 30011;‘ ,
spaced~pulleys;_.a tensioned steel tape supported
2,576,546 _
17
on said pulleys; one of said carriages including
means for locking it to one run of said tape and
a releasable clamp on the other of said carriages
disposed to engage the other run of said tape.
10. In a machine for producing on a plate from
an image sheet a relief pattern suitable for image
18
a pair of sychronously rotatable cylinders for in
dividually supporting. a plate and an image sheet
and a pair of reciprocable carriages individually
including a pick-up system and a plate-deforming
tool for respectively scanning said image-sheet
cylinder and said plate cylinder, a positioning and
reproduction by printing processes and including
actuating mechanism for said plate-deforming
a pair of rotatable cylinders for individually sup
tool comprising: a tool actuating assembly includ
porting a plate and an image sheet and a pair of
ing a plate-deforming tool; means for determm
reciprocable carriages individually including a 10 ing the neutral position of said tool assembly;
pick-up system and a plate-deforming tool for
electromagnetic means connected to respond to
respectively scanning said image-sheet cylinder
the output of said picK-up system for actuating
and said plate cylinder, a common drive shaft for
said tool; and means for producing a pulsating
said cylinders including a disengageable coupling;
excitation of said actuating means at a screen
a mechanism for reciprocating said carriages 15 frequency; the speed of‘ said cylinders being so
synchronously in opposite directions to obtain an
related to the frequency of saw. excitation that
inverted relief pattern comprising: a pair of
the peripheral travel of said cylinders during one
spaced pulleys; a tensioned inelastic belt sup
period 01‘ said excitation is approximately twice
ported on said pulleys; one of said carriages in
the desired llne spacing.
cluding means for looking it to one run of said 20
14. In a machine for producing on a plate from
belt and a clamp on the other of said carriages
an image sheet a relief pattern suitable for image
disposed to engage the other run of said belt and
reproduction by printing processes and including
releasable to permit independent adjustment of
a pair of synchronously rotatable cylinders for
said other carriage upon disengagement of said
individually supporting a plate and an image
coupling.
25 sheet and a pair of reciprocable carriages inci
11. In a machine for producing on a plate from
an image sheet a relief pattern suitable for image
vidually inclucnng a pick-up system and a plate
deiormlng tool 101' respectively scanning said;
reproduction by printing processes and including
plate cyllnder and said image-sheet cylinder, a
a pair of synchronously rotatable cylinders for
positioning and actuating mechanism for said
individually supporting a plate and an image 30 plate-aelorming tool comprising; a tool actuat
sheet and a pair of reciprocable carriages in
ing assembly including a plate-deforming tool;
dividually including a pick-up system and a plate—
means I01‘ biasing said tool assembly into engage
deforming tool for respectively scanning said
ment with said plate cylinder; said tool assembly
image-sheet cylinder and said plate cylinder, a
including an adjustable shoe engaging a plate on
positioning and actuating mechanism for said
said plate cylinder for determining the neutral
plate-deforming tool comprising: a tool actuating
position of said tool; electromagnetlc means con
assembly including a plate-deforming tool; means
nected to respond to the output of said pick-up
for determining the neutral position of said tool
system for actuating said tool; and means for
assembly; electromagnetic means connected to
producing a pulsating excitation of said actuating
respond to the output of said pick-up system for ~10 means at a screen frequency.
actuating said tool; and means for producing a
15. A machine ror producing on a plate from,
pulsating excitation of said actuating means at
an image sheet a screened relief pattern suitable
a screen frequency; the amplitude of said pulsat
for image reproduction by printing processes
ing excitation being so proportioned to the con
comprising; plate ,and image-sheet supports;
stants of said actuating means that the mean
means including an electro-optical pick-up sys
penetration of a plate by said tool is of the same
tem'for scanning an image sheet on its support;
order of magnitude as the neutral separation of
means including a plate-deforming tool for scan
said tool and its plate.
ning a plate on its support synchronously with
12. In a machine for producing on a plate from
said ?rst scanning means; means responsive to
an image sheet a relief pattern suitable for image
the output of said pick-up system for actuating
reproduction by printing processes and including
said tool; a periodic electrical screen generator
a pair of synchronously rotatable cylinders for
connected to modulate the output of said pick-up
individually supporting a plate and an image
system; and means for adjusting the output of
sheet and a pair of reciprocable carriages in
said generator to adjust the minimum deforma
dividually including a pick-up system and a
tion of said plate corresponding to the black level
plate-deforming tool for respectively scanning
of an image sheet.
said image-sheet cylinder and said plate cylinder,
16. A machine for producing on a plate from
a positioning and actuating mechanism for said
an image sheet a screened relief pattern suitable
plate-deforming tool comprising: a tool actuating
for image reproduction by printing processes
assembly including a plate-deforming tool; means 60 comprising: plate and image-sheet supports;
for determining the neutral position of said tool
means including an electro-optical pick-up sys
assembly; electromagnetic means connected to
tem including a light source for scanning an
respond to the output of said pick-up system for
image sheet on its support; means including a
actuating said tool; and means for producing a
plate-deforming tool for scanning a plate on its
pulsating excitation of said actuating means at 65 support synchronously with said ?rst scanning
a screen frequency; the amplitude of'said pulsat
means; means responsive to the output of said
ing excitation being so proportioned to the re
pick-up system for actuating said tool; a peri
sponse of the pick-up system that the minimum _
odic electrical screen generator connected to
penetration of said tool corresponding to one
modulate said light source; and means for apply
shade extreme in said image is of the order of 70 ing an adjustable portion of the output of said
one-?fth its maximum penetration corresponding
generator to said tool actuating means to adjust
to the other shade extreme.
the minimum deformation of said plate corre
13. In a machine for producing on a plate from
sponding to the black level of an image sheet.
an image sheet a relief pattern suitable for image
17. A machine for producing on a plate from
reproduction by printing processes and including 15. an image sheet a screened relief pattern suitable
194
for image reproduction ‘by‘printing processes:
comprising: plate and image-sheet supports;
means including. an-electro-optical pick-upsys-v
20
a. second ampli?er‘ coupled to saidlgeneratoryi
means for combining. the outputs ofisaidrv amplie
?er's; meanslresponsive to said combined ‘outputs;
for actuatingssaidf tool; means for adjustingthe.
tem including a light source for scanning an
image‘ sheet on its support; means including a 5 output of said generatorampli?er-to;adjust-the
plate-deforming. tool- for scanning a plate» 0n~its1
minimumv deformation of said plate corresponding.
support synchronously with“ said ?rst scanning»
to theblack- level of an. image- sheet; andimeans for‘
adjusting the output. of said ‘pick-up system
ampli?er to adjust the maximum deformation of
said.plateucorresponding to the‘: white level offan.
image sheet.
22.. Amachineior producing‘ona'.platefrom an.
image sheet a. screened ‘relief pattern suitable‘
for image reproduction by printing processes‘ com:
an image sheet a screened relief pattern suitablefor image» reproduction byprinting processes 15 prising: plate.- andimage-sheet ‘supports; means
including. an electro-optic‘ak pick-up system‘: for
comprising; plate ‘and image-sheet» supports;
scanning an image sheet on. its support; means
means including anelectro-optical pick-up. sysincluding a plate-deforming tool for; scanning. a.
tem including a light source for scanning‘. an;
plate on its support synchronously with said: ?rst
image sheet on its support; means including a
plate-deforming toolu-for scanning-a- plate ion. its 20 ‘scanning means ;; means responsive to. the output
support’ synchronously» with saidm-?rsthscanning.» of said pick-up system-for actuating said tool; a
source of periodic potential connected to modu
means;- a ?rstampli?er coupled-to. the outputot _
late the. outputof said. pick-up: system ;:' and means
said pick-up. system; - a .periodie'electrical» screen I
responsive to the'failure of saidsource for actuat
generator; a second # ampli?ercoupled to. said».
generator; means for»v combining adjustable por-.. 25 ing said tool to an inoperative position.
23. A. machine for producing. on a plate from
tions. of the outputs of said. ampli?ers; :and means
means; a ?rst ampli?er coupled vto the output of
said pick-up system; a. periodieelectrical» screen
generator; a second ampli?er-coupled to= said-10generator; and means responsive~jointly~toithe~
outputs of said ampli?ers for actuating said tool.
18. A- machine'for producing-on arplate'i’rom
responsivetosaid-combined outputsior actuating.»
an image-sheet a: screenedrrelief pattern suitable
said tool.
for image reproduction by printing processes-Zoom
prising:_ plate and image-sheet supports; means
.
1-9. A machine for producing 'on- a platecfrom»
an imagesheet a screenedl‘relief patternrsuitable 30 including an electro-ol?tical pi?k-llp System for
for image- reproduction. by printing processes. “ scanning an image. sheet on its support; meansin
eluding a plate-deforming tool for scanning: a
comprising’: plate-‘1 and. ‘image-sheet supports;
plate on its support synchronously with said first
means including an. electroeopticalv pick-up sys-.
scanning means; means for'biasing saidgtool. to an
tem for scanning an image‘ sheet on its. support}.
means- including a plate-deforming tool for scans. 35 inoperative position; a normally excited electro
magnetic means forretainingsaid tool in an op
ning a plate on: its support... synchronously. with.
erative position; meansresponsive. to the output
said ?rst scanning. means;v means responsive: to
of said pick-up system for‘ actuating‘ said tool; a
the outputof said: pick-up system for actuating
source of periodic potential connected to modu
said tool; a periodic. electrical. screen generator.
late the output of saidpick-up system; and means
connected to modulate: thev output: or said-pick-up.
responsive, to the failure of said. source for de
system; and means. for adjusting the outputof
said pick-up system to adjustthe maximum de
formation of- said-plate. corresponding touthe.v
energizing said electromagneticmeans.
forv image reproduction‘ by printingprocesses.
comprising-1:’ plate and-l image-sheet» supports ;:v
including. an. electro-optical pick-up system for
24. A machine for producing- an a plate. from»
an image‘ sheet a screened relief pattern suitable
white level of an image sheet.
for» image reproduction by printingprocesses com- 20. A- machinev for‘ producingon a. plate from.
an image sheet a‘ screened. relief pattern suitable. 45 ‘prising: plate-and image-sheet supports; means
means including» an“ electro-opticaler pick-upsys»
scanning an image sheet on its support; means
includingv a plate-deformingtool for. scanning a
plate on its support synchronously withsaid ?rst
tem‘ for scanning-van image sheet'on its support;-~
means includinga plate-deformingetool' for scan- <50 scanning means; means including an. ampli?er
responsive to. the output of said. pick-up system.
ning a plate on-itssupport synchronously-i-wi-thv»
for.
actuating said tool; a ?lter network coupled
said ?rst scanning means; meansresponsive'tcrv
to said. ‘ampli?er for eliminating the onset. of
the- output of said» pick-up‘ system for actuating
variations. of the mean. brightness of. an. image
said» tool, a periodic electrical screengenerator- 55 sheet on the mean position of said- tool‘; and a
connected to modulate the output of said pick-up»
source of‘ periodic potential of screen frequency
system; means for adjusting the output of- said
connected to modulate‘ the output of‘ said pick’
generatorto- adjust the minimumdeformation of
up system. ‘
said plate corresponding to the black-level'of an
25. A'machine ‘for producing on a. plate from~
image‘sheet? and‘ means for'adj'us?ng theoutput’?d an image sheet av screened relief ‘pattern suitable‘
of said pick-up system-substantially- independ»
for image reproduction by printing processes com
ently to adjust the maximum: deformation ofisaid
prising‘: plate and image-sheet supports; means
plate corresponding to the- white“ level of an»
including an electro-optical' pick-‘up, system'for'
image ‘sheet.
scanning an image sheet'on itssupport-y means
21- A machine’ for producingon‘ ‘31 platecf'rlom" Bd’includinga plate-deforming tool for scanning a
an. image: sheet: a screened relief pattern» suitable -
forv image~.1.'eproduction by- printing processes
comprising:- plate and image-sheet- supports;
means including anelectro-optical pick-up system
plate‘ on its support‘ synchronously with said?rst
scanning means; means including an amplifier
responsive totheoutput of‘ said pick-upsystem
actuating‘ said tool’; »a low~passvv inverse feed-back
including alight source; for scanning an image mJnetwork coupled to said amplifier-for eliminating
sheet‘ on. its support; means. including a plate.»
the e?ect of variations of the mean brightness
deforming tool. for; scanning. a. plate on-itssupport
synchronously with: said; ?rst. scanning: means}, a»
of an image sheet on the mean- position' of said‘
tool ;-and a source of periodic potential of screen
frsttampli?jer coupled: to the output of said'rpick
frequency connected to modulate the output’ of
up. systenn: aperiodicelectricalLscreeng generatog: 751‘said-pick-up-system. ~ »
21
9,575,546
26. A machine for producing on a plate from
an image sheet a screened relief pattern suitable
for image reproduction by printing processes com
prising: plate and image-sheet supports; means
including an electro-optical pick-up system for
scanning an image sheet on its support; means
including a plate-deforming tool for scanning a
plate on its support synchronously with said ?rst
scanning means; means responsive to the output
of said pick-up system for actuating said tool;
22
plate on its support synchronously with said ?rst
scanning means; means responsive to the output
of said pick-up system for actuating said tool; a
source of periodic potential of screen frequency
connected to modulate the output of said pick
up system; a portable microscope adjustable for
focusing on a plate undergoing deformation and
including a stroboscopic light source; and a cir
cuit for exciting said light source from said
periodic source.
a source of periodic potential of screen frequency
connected to modulate the output of said pick
up system; and a stroboscopic viewer ior said
plate including a light source energized from said
source.
27. A machine for producing on a plate from
an image sheet a screened relief pattern suitable
JOHN A. BOYAJEAN, JR.
REFERENCES CITED
The following references are of record in the
?le of this patent:
UNITED STATES PATENTS
Name
Date
for image reproduction by printing processes com
Number
prising: plate and image-sheet supports; means
2,063,614
including an electro-optical pick-up system for 20 2,079,970
scanning an image sheet on its support; means
2,179,002
including a plate-deforming tool for scanning a.
2,489,691
McFarlane ________ __ Dec. 8, 1936
Speed ____________ __ May 11, 1937
Washington, Jr. ____ Nov. 7, 1939
Washington ______ __ Nov. 29, 1949