Device for producing images on printing image carriers

Claim 2

An electric image producing device for use in conjunction with a printing image carrier of a printing press comprising at least one writing unit, in the form of an electrode means, for modifying said printing image carrier in a local and punctuate manner, said at least one writing unit being adapted to be connected with an electrical power supply and including means for driving it in accordance with an image on said printing image carrier, said printing image carrier being able to be modified electrochemically and said writing unit comprising a control electrode and a field forming intermediate electrode, which are same being at partly immersed in an electrolyte.

Claim 3

The device as claimed in claim 1 wherein said field forming electrode is in the form of a bell with a floor having a central aperture for forming a diaphragm through which said electrolyte may flow onto the printing image carrier.

Claim 4

The device as claimed in claim 1 comprising a plurality of said control electrodes and said intermediate electrodes, the same being arranged in a plurality of pairs with one control electrode and one intermediate electrode in each pair and such pairs being arranged in at least one row with a common carrier for the same.

Claim 5

The device as claimed in claim 3 wherein the pairs of control and intermediate electrodes are arranged in at least two rows with an offset from row to row of half the pitch in one of the rows.

Claim 6

An electric image producing device for a printing image carrier of a printing press comprising at least one writing unit, including an electrode, for modifying a printing image carrier in a local and punctuate manner, an electrical power supply for said writing unit, said writing unit further including a stylus, a photoconductor for connecting said stylus with the electrical power supply via said electrode, a punctuate light source associated with said stylus and positioned for modifying the photoconductor in a locally restricted, timed manner to establish an electrical connection between said electrode and said stylus, and switch means between the light source and the photoconductor for selectively controlling the passage of light from said light source to said photoconductor in accordance with the image to be produced on said printing image carrier.

Claim 7

An electric image producing device for a printing image carrier of a printing press comprising at least one writing unit, including an electrode, for modifying a printing image carrier in a local and punctuate manner, an electrical power supply for said writing unit, said writing unit further including a stylus, a photoconductor for connecting said stylus with the electrical power supply via said electrode, a punctuate light source associated with said stylus and positioned for modifying the photoconductor in a locally restricted, timed manner to establish an electrical connection between said electrode and said stylus, and switch means between the light source and the photoconductor for selectively controlling the passage of light from said light source to said photoconductor in accordance with the image to be produced on said printing image carrier.

Claim 8

The device as claimed in claim 5 comprising a light guide for directing light from the light source onto the photoconductor via said switch means.

Claim 9

The device as claimed in claim 6 comprising a plurality of separate light guides for said stylus.

Claim 10

The device as claimed in claim 5 wherein said switch means comprises a magneto-optic light switching module.

Claim 11

The device as claimed in claim 8 comprising a light guide for directing light from said light source onto the photoconductor via said magneto-optic light switching module, said light guide including a first portion between the light source and said module and a second portion between the module and the photoconductor such that light can pass through said first portion, then through said module when said switch means is open and thereafter through said second portion.

Claim 12

The device as claimed in claim 9 wherein a plurality of said styluses are provided, each stylus being associated with a different number of respective light guides connecting the stylus with said light source, each light guide having a respective magneto-optic light switching module associated therewith.

Claim 13

The device as claimed in claim 5 wherein a plurality of said styluses are provided in an arrangement of at least one row, said photoconductor and said electrode being connected in common to all of said styluses, said electrode being transparent to the light from said light source.

Claim 14

The device as claimed in claim 11 wherein said photoconductor comprises a layer to which said plurality of styluses are connected.

Claim 15

The device as claimed in claim 5 wherein the printing image carrier comprises a ferroelectric layer.

Claim 16

The device as claimed in claim 5 wherein said photoconductor and said electrode are in the form of layers between said stylus and said light source.

Claim 17

The combination comprising a plate member of a printing press, a printing image carrier mounted on said plate member, said printing image carrier having a surface wettable by printing ink to form an image which can be printed on a substrate, and an electric image producing means for producing a selective electric field on said surface of the printing image carrier for affecting the wettability of said surface in accordance with the image to be printed, said electric image producing means comprising at least one writing unit, including an electrode, for modifying said printing image carrier in a local and punctuate manner, said at least one writing unit being adapted to be connected with an electrical power supply and further including means for operating said unit in accordance with the image to be produced on said printing image carrier, said writing unit comprising a stylus, photoconductor means for selectively and controllably connecting said stylus with the electrical power supply, and a punctuate light source for operating the stylus and for modifying the photoconductor means in a locally restricted, timed manner, the light from said light source being associated with said stylus and being able to be directed to the photoconductor means.

Claim 18

The combination comprising a plate member of a printing press, a printing image carrier mounted on said plate member, said printing image carrier having a surface wettable by printing ink to form an image which can be printed on a substrate, and an electric image producing means for producing a selective electric field on said surface of the printing image carrier for affecting the wettability of said surface in accordance with the image to be printed, said electric image producing means comprising at least one writing unit, including an electrode, for modifying said printing image carrier in a local and punctuate manner, said at least one writing unit being adapted to be connected with an electrical power supply and further including means for operating said unit in accordance with the image to be produced on said printing image carrier, said writing unit comprising a stylus, photoconductor means for selectively and controllably connecting said stylus with the electrical power supply, and a punctuate light source for operating the stylus and for modifying the photoconductor means in a locally restricted, timed manner, the light from said light source being associated with said stylus and being able to be directed to the photoconductor means.

Claim 19

The combination as claimed in claim 15 comprising switch means between the light source and the photoconductor means for selectively controlling the passage of light from said light source to said photoconductor means in accordance with the image to be produced on said printing image carrier.

Claim 20

The combination as claimed in claim 16 comprising a light guide for directing light from the light source onto the photoconductor means via said switch means.

Claim 21

The combination as claimed in claim 17 comprising a plurality of separate light guides for said stylus.

Claim 22

The combination as claimed in claim 15 wherein said switch means comprises a magneto-optic light switching module.

Claim 23

The combination as claimed in claim 19 comprising a light guide for directing light from said light source onto the photoconductor means via said magneto-optic light switching module said light guide including a first portion between the light source and said module and a second portion between the module and the photoconductor means such that light can pass through said first portion, then through said module when said switch means is open and thereafter through said second portion.

Claim 24

The combination as claimed in claim 20 wherein a plurality of said styluses are provided, each stylus being associated with a different number of respective light guides connecting the stylus with said light source, each light guide having a respective magneto-optic light switching module associated therewith.

Claim 25

The combination as claimed in claim 15 wherein a plurality of said styluses are provided in an arrangement of at least one row, said photoconductor means and said electrode being connected in common to all of said styluses, said electrode being transparent to the light from said light source.

Claim 26

The combination as claimed in claim 22 wherein said photoconductor means comprises a layer to which said plurality of styluses are connected.

Claim 27

The combination as claimed in claim 15 wherein the printing image carrier comprises a ferroelectric layer.

Claim 28

The combination as claimed in claim 15 wherein said photoconductor means and said electrode are in the form of layers between said stylus and said light source.