US1719621A - Machine for producing printing plates - Google Patents

Description

y 1929- F. D. PEARNE ET AL MACHINE FOR PRQDUGING PRINTING PLATES Filed April 11, 1927 3 Sheets-Sheet l July 2, 1929. F. D. PEARNE ET AL 1,719,621

MACHINE FOR PRODUCING PRINTING PLATES Filed April 11, 1927 5 SheetSTSheet 2 y 1929- F. D. PEARNE ET AL 1,719,621

MACHINE FOR PRODUCING PRINTING PLATES Filed April 11, 1927 5 Sheets-Sheet 3 Patented July 2, 1929.

UNITED STATES 1,719,621 PATENT OFFICE.

FRANK n. PEARNE, or cnrcAco, AND IRVING R. METCALF, or GLEN ELLYN, rumors, AND WALTER HOWEY, on NEW YORK, N. Y.; MARTHA x. PEARNE EXECUTRIX or LAs'r WILL or SAID FRANK D. PEARNE, DECEASED.

MACHINE FOR PRODUCING PRINTING PLATES.

Application filed April 11, 1927. Serial No. 182,877.

This invention relates to a machine for producing printing plates and the like directly from a picture or image.

Heretofore in producing plates or cuts, the image was photographed on a sensitized plate which was afterwards treated or processed so that the plate was suitable for printing a reproduction of the picture. is for example, in making half-tones, the picture was scanned or broken up into small parts by a screen which was placed over the photograph with the result that the image was reproduced by heavy and light dots 1n the sensitized surface of the plate. Then the plate was etched and processed to leavethe dots standing in relief for taking the ink. Many distinct steps were required each of which necessitated great care and skill.

Therefore, it is the main object of this invention to provide means for preparing the surface of the plate directly from the image by an automatic mechanical process-to re duce the expense and to facilitate the production of the plates. I

In this invention, the picture or image is scannedby means of a beam of light which.

is caused, in eifect, to travel over the surface of the picture in somewhat the same manner as is done in certain photo-telegraphic apparatus; while the translation or reproduction is made directly on a printing plate by means of a pointed tool cutting to a depth controlled by the light beam. Since the point of the tool is bluntly tapered, the area'of the surface removed is of course a direct function of the depth of the cut which is controlled by the intensity of the reflected light from the different parts of the picture.

An illustrative embodiment of this invention is shown in the accompanying drawings in which:

Figure 1 is a diagram of the plate-making machine, with the carriage shown in side elevation.

Fig. 2 is a plan view of the carriage portion.

Fig. 3 is a section taken on the line 3-3 of Fig. 2.

Fig. 4 is a arrangement. 4

Fig. 5 is an enlarged detail of the end of diagram showing a modified the drill, or reproducing tool.

Fig. 6 is an enlarged section through the printing plate.

In the drawings is illustrated a machine more especially intended for making halftones, or cameo relief plates, in which the ink 1s deposited on the surface of the plate. Obviously the machine may be adapted for mechanical gravurc work where parallel lines shaded in width are used, or for intaglio plates where the ink is deposited in the recess and the surface wiped ofi.

The picture 7 and the printing plate 8 which is to be prepared, are mounted in spaced relation on the surface of the carriage 9. The carnage is longitudinally slidable on the sub-carriage 10, which is mounted trans versely slidable on the base 11. The carriage i) 1s resiliently pressed to the right as shown in F1g. 1 by means of a coil spring 12 which bears against a lug 13, integral with the subbase 10. A cam roller 14 is rotatably mounted on the opposite end of the carriage member 9, and is pressed into contact with the periphery of the driving cam 15 which is rotatably mounted on the sub-base 10. The cam 15 is continuously rotated by means of the motor 16 mounted on the sub-base 10, and connected through any suitable form of speed reducing transmission as represented at 17. The profile of the cam 15 is such that the carriage is 'reciprocated at an even rate of speed in either direction. A

At the end of each reciprocation of the carriage 9, the sub-base 10 is moved laterally by means of the feed screw 18, which is rotatably mounted inthe sub-carriage, and engages in a feed nut 19 which is attached to the base 11. This feeding is accomplished by means of a pawl and ratchet actuated by. the pin 20, which is mounted on the carriage 9. The ratchet wheel 21 is fixedly secured to the outer end of the feed screw 18, and the pawl 22 is pivotally mounted on the upper end of the lever 23 which is rotatably mounted on the feed screw 18. The lower end of the lever 23 is connected by means of the link 24 to a plunger 25 which is slidably mounted in a housing 26, secured to the subcarriage 10. The plunger 25 is resiliently pressed to the left as viewed in Fig. 1 by means of the coil spring 26', this movement being stopped by the collar 27 which is secured on the right end of the plunger 25, and strikes against the housing 26. Atthe end of the movement to the right, the pin 20 strikes the end of the plunger 25, and moves the ratchet wheel 21 counter-clockwise. lVhen the carriage moves to the left, the pm strikes directly on the pawl 22, and again moves the carriage in the same direction.

' The means for directing abeam of light against the picture is shown as comprising a suitable source of light and a lens 31 or focusing the light. The beam is directed against the picture at an angle, and the reflected light is focused by means of the lens 32 upon a suitable photo-electric cell 33. The members 30, 31, 32 and33 are mounted in fixed relation with the base 11.

The drill 34 is also mounted in a fixed posi-' tion with relation to the base 11, to operateon the surface of the plate 8. The drill 34 is mounted to rotate in a frame 35 which is pivoted on a shaft 36 which is in fixed relation to the base 11. The frame 35 is resiliently lifted by means of a contractile spring 37 against the fixed sto) 38, and is pulled downwardly by means 0 the electro-magnet 39. A small motor 40 is shown mounted on the frame 35 for rotating the drill, and the motor is also connected for driving a circuit breaker 41, also mounted on the frame 35. From the above description, it will now be seen that the picture is scanned in a series of parallel lines by the light beam, and that the drill travels over the surface of the plate in exactly the same manner as the beam travels over the surface of the picture.

The photo-electric cell 33 is connected by means of a conductor42 throughthe. battery I 43 and the primary coil 44 of a transformer 45. The secondary 46 of the transformer is connected in circuit with the grid 47 of the three-element tube 48 which is connected through the second tube 49 to the circuit 50 to amplify current which flows through the photo-electric cell 33. The circuit 50 includes the electro-magnet 39 and is connected through the interrupter 41 as shown.

Since the amount of current that canflow through the photo-electric cell 33 increases according to the amount of light reflected into the cell, the lighter spots in the picture will increase the amount of energy in the electro-magnet 39 and draw the drill, or cutting tool 34 deeper into the surface of the plate while less light will be reflected from the darker points in the picture, and the amount of energy in the magnet 39 and the penetratio r of a drill will be proportionately decreased. The fluctuations in the reflected beam will be translated continuously into the amplifying circuits, and to the circuit 50, but the drill will be fed downwardly in an intermittent manner because of the action of the circuit interrupter 41.

In the form'shown in Fig. 4, the drill 34 is pulled down by the magnet 51 against a stop 52, and is controlled by the fluctuating currents, as in the preceding'form. The drill 34 is mounted to rotate in the frame 53, which is pivoted on a fixed shaft 54. The motor 56 I er 57. As the magnet 60 is energized, it attracts a diaphragm 62, to which the end of the stop member 52 is attached. The stop member 52 is represented as being slidably mounted on a suitably fixed support 63, and is provided with an inclined cam surface 64 to cooperate with a pointed contacting member 65, which is fixed on the frame 53.

As, the reflection of the beam of light from the picture varies, the stop member 52 will be positioned responsive thereto so that the contact 65 strikes on higher or lower portions of the cam surface 64. Since the pulled-down magnet 51 is energized at regular intervals and the position of the stop 52 is controlled by the amount of light reflected at the points in the picture, the image will be reproduced on the surface of the plate in the same manner in the-ordinary half-tone cuts, as will be readily understoo A proposed form of the drill point is shown in Fig. 5. The point is profiled so that, for even graduations in depth, the diameter increases in a regular manner; the object being to-proportion the drill so that the area of the surface removed is a direct function of the depth of the cut. Thus, as shown in Fig. 6, the greater portion of the surface is left untouchedto reproduce a dark portion.

of the picture, a part of the surface is cut away to reproduce various shades. and all of the surface is removed to reproduce white portions of the picture.

While but one specific embodiment of this invention has been herein shown and described, it will be understood-that numerous details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

lVe claim:

1. A machine for reproducing a picture on the surface of a plate, comprising a transmitter including means for scanning the pic-' ture and transforming the variations of shad- .ing into electrical pulsations, a translator connected to the transmitter and including a plate cutting tool controlled by said pulsations, and an interrupter for interrupting the electrical pulsations between the translator and the transmitter to cause the tool to out intermittently.

2. A machine for reproducing a picture on a plate, comprising a transmitter including means for scanning the picture and including means for transforming the variations in the shading of the picture into an electrical pulsating current, a translator connected to the transmitter and including a plate cutting tool having a tapered point, the tool adapted to cut to a depth controlled by said current, and means for interrupting the current to cause the tool to cut intermittently.

3. A machine for reproducing a picture on the surface of a printing plate, comprising means for directing a beam of light to travel continuously over the picture, a means for transforming the variations in the light reflected from the picture into a pulsating electrical current, a plate cutting tool controlled by the current, and an interrupter for the current to cause the tool to cut intermittently.

4. The combination in a machine for reproducin g a picture on a plate, of a drill mounted to travel over the surface of the plate and normall raised therefrom, an electromagnet for feeding the drill into the plate, a photo-electric cell controlling the amount of feeding a circuit including an electrical source and the electromagnet, and an interrupter in said circuit.

5. In a machine for reproducing a picture on the surface of a' plate, a translator comprising a movably mounted frame, a drill rotatably mounted in the frame, means for reciprocating the frame tofeed the drill into the plate, an adjustable stop for the frame for regulating said feeding movement, and electromagnetic means controlled by the shading on the picture for adjusting the stop.

6. In a machine for reproducing a picture on the surface of a printing plate, a translator comprising a. pivotally mounted frame, a drill rotatably mounted in the frame, means for reciprocating the frame to feed the-drill into the plate, a movable stop having an inclined surface cooperating with the frame to limit the feeding movement, and photo-electric means for ositioning the stop in accordance with the s ading of the picture.

7 In a machine for reproducing a picture on the surface of a plate, a translator comprising a movably mounted frame, a drill rotatably mounted in the frame, means for reciprocating the frame to feed the drill into the plate, a movable stop having an inclined surface cooperating with frame to stop the feeding movement of the frame, and electromagnetic means controlled by the shading on the picture for positioning the stop.

8. In a machine of the class described, a holder for an image and for a plate for receiving an engraved reproduction of an image, an engraving tool having a tapered cutting point, aprimary electrical circuit, light sensitive means for varying the resistance .of said circuit, means for focusing on said age on said holder, a secondary circuit with amplifying means therein, an interrupter in said secondary circuit, and electromagnetic means for operating said drill under April,

the control of said secondary circuit. Signed at Chicago this 9th day of FRANK D. PEARNE.

' IRVING R. METOALF.

Signed at New York this 5th day of Aprll,

1927. y WALTER HOWEY.

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