SU142149A1 - Electro-engraving machine for the manufacture of embossed printing plates - Google Patents

Description

Electro-engraving machines for making embossed printing plates are known, including a photo head for progressively reading a reproduction original, an electronic circuit for amplifying and transforming, a control signal, and a cutting head for reproducing the printing pattern. In known machines of the same purpose, a continuous change in the signal at the system input (change in the tonality of the original) corresponds to a continuous change in the signal at the output (force on the engraving system). Thus, these machines have a continuous amplitude response. In order to better distinguish especially dark or light fields of the original, this characteristic is given an appropriate shape by means of an electronic corrector; However, the use of such correctors does not give the required technical effect.

When using the corrector, the slopes (steepness) of different parts of the amplitude response zones to one degree or another depend on one another, therefore when the tonality of one part of the original changes, the tonality of the other part changes. A system with a continuous amplitude characteristic makes it impossible to single out any single tone, not the same for the rest of the print tonality, or to get a full-fledged print with a wide range of gradations from an underexposed, veiled or overexposed original. It is not possible directly to obtain inversion cliches or correct cliches from a negative.

The proposed electrogravure machine, in contrast to the known ones, allows changing the tonality of any print floor regardless of the rest of the print tonality, which expands the operational capabilities of the machine. With this purpose, the device for converting the floating characteristic of the machine into a stepped one is introduced into the electronic circuit. The device can be made in the form of a cathode ray tube, on one pair of deflecting plates of which the amplified and straightened pulses of the photo head are fed, and on the other 142149-2 pair of pulses of the raster frequency generator, and in front of the screen of the electron-beam tube a mosaic of photoconverters is mounted Isolated from one another connected on the one hand to the power source and on the other to an electronic relay, the output voltage of which is regulated by a potentiometer and fed to the winding of the cutting head.

FIG. 1b The principle electronic circuit for converting a smooth amplitude characteristic of a machine into a stepped one; in fig. 2-diagram of the inclusions of mosaic photoconverters; in fig. 3-diagram of the cell of the electronic relay and the output stage.

Photohead 1 (similar to that used in any electro-engraving machine) reads out reproduced original 2 line by line. Signals from the photo head enter amplifier 3, then are rectified by detector 4 and sent further one pair of deviations from their cathode-ray tube 5. The position of the beam on the horizontal straight screen of the tube 5 is determined by the magnitude of the signal; the most white field of the reproduced original (the largest signal) corresponds to the extreme right position of the beam; the blackest field is the extreme left position of the beam; Intermediate key marks — intermediate beam positions. The beam path is determined (at a given cathode ray tube) by the gain factor of amplifier 3,

In front of the screen of the tube 5 is mounted a mosaic (set) of 6 photoconverters 7 of photoresistances or photodiodes.

Photo converters 7 (in the amount of 24 pcs., Which with a large margin exceeds the possible number of brightness fields that can be transmitted on the Polygraphic imprint) are end-to-end to each other and their photosensitive layers are isolated from one another by a layer of 8 mica (0.1 mm thick The beam on the screen of the tube is approximately 20–25% smaller than the size of the photoconverter. On the vertical deflecting plates of the cathode ray tube pulses from the raster frequency generator 9 are given constant amplitude; the frequency of these pulses corresponds to tstvuet engraving screen ruling; amplitude such that the beam under the influence of the raster pulse is lowered to a mosaic of photoconverters 6.

Thus, in the process of reading the original by the photohead, the beam illuminates with a raster frequency one or another mosaic transducer according to the tonality of the readable spot of the original. All photoconverters 7 of mosaic 6 are connected on one side to a power source, and on the other through plugs 10 and a switching panel // to an electronic relay system 12, the number of which corresponds to the number of elements of a mosaic 6 of photoconverters 7; all their outputs are connected in parallel to the signal winding 13 of the cutting head. All electronic relays have a common power source, and the voltage at their output, regulated by a potentiometer R, is selected so that the signal of the first relay corresponds to the minimum engraving depth, and the last corresponding to the maximum.

Moving the beam along the mosaic 6 ensures that all fields on the print are received. Thus, the mosaic of 6 photoconverters 7 and the system of electronic relays give amplitude a step response with any predetermined number of stages.

By changing the voltage with an RI potentiometer, at the output of any electronic relay, it is possible to change the tonality of any half scale from black to white, without changing the tonality of all other fields. Swapped plugs 10 on the patch panel 11 (for example, by rearranging the plug first into place of the twentieth plug, etc.),

You can cut the correct cliche from a negative image or, conversely, a reversal from the original.

If the original is dark, veiled (overexposed) and has no bright fields and clear gradations, it is enough to increase the gain so that the rightmost field of the mosaic matches the rightmost field of the mosaic, and the left is dark, and then the impression is clear and distinct. range of gradations.

Similarly, if the original is clarified (underexposed), then the position of the beam against the leftmost mosaic floor and the lightest (raised in a gain) position against the rightmost mosaic floor are set to the TeNiHOMy's most appropriate location and opposite to the rightmost mosaic floor.

The electrogravating machine described is recommended for review by the All-Union Research Institute of the Printing Industry, according to the conclusion of which this proposal makes it possible to create an arbitrary gradational characteristic of engraving in discrete engraving machines and to improve the quality for all originals.

Subject invention

Claims (2)

1. An electrogravure machine for making embossed printing plates, including a photo head for progressive reading of a reproduced original, an electronic circuit for amplifying and transforming a control signal, and a cutting head for reproducing the printing pattern, so that expanding the operating capabilities of the machine; a device for converting the smooth amplitude characteristic of the machine into a stepped one is introduced into the electronic circuit. 2. The electrogravure machine according to claim 1, wherein the device for converting a smooth amplitude characteristic into a stepped one is made in the form of a cathode ray tube, for which one pair of deflecting plates of which amplified and rectified pulses are applied photo heads, and another pair of pulses of the raster frequency generator; In front of the tube screen there is mounted a mosaic of photovoltaic cells, isolated from one another and connected to the power supply on the one side and to an electronic relay, on the other hand, the output voltage of which is regulated by a potentiometer and fed to the winding of the cutting head. 72 mache 1 socket on the patch panel d khalnyi diode Riga.1