Empty Separation Printing

Patent metadata

Field	Value
Publication number	US-2019033744-A1
Application number	US-201616072288-A
Country	US
Kind code	A1
Filing date	May 9, 2016
Priority date	May 9, 2016
Publication date	Jan 31, 2019
Grant date	—

Abstract

An apparatus is provided for controlling a liquid electrophotography printer (LEP). The LEP may include a plurality of ink developers, IDs, to transfer charged ink to a photoreceptor, by virtue of a potential difference between the engaged ID and the photoreceptor selectively dischargeable to allow an image to be formed on a print medium in use through printing a spread of plural colour separations thereon each corresponding to ink from one of a plurality of engaged IDs. the apparatus may comprise a print controller to, in use monitor an order of colour separations to be printed onto the print medium. The print controller may also detect in the order of colour separations an empty separation of an ID followed by a printing separation of the same ID, an empty separation representing a separation in which no image is formed on the photoreceptor and the engaged ID is at a voltage different to the voltage of the ID for a printing separation so as to, in the empty separation, substantially wet the photoreceptor and substantially not transfer ink thereto. The print controller may also, in response to the detection, replace in the order of the colour separations the ID for the empty separation with a different ID.

First claim

1 . An apparatus for controlling a liquid electrophotography printer comprising a plurality of ink developers, IDs, to transfer charged ink to a photoreceptor the apparatus comprising a print controller to, in use:
monitor an order of colour separations to be printed onto the print medium; detect in the order of colour separations an empty separation of an ID followed by a printing separation of the same ID, an empty separation representing a separation in which no image is formed on the photoreceptor and in which an ID is engaged with the photoreceptor and is at a voltage different to the voltage of the ID for a printing separation so as to, in the empty separation, substantially wet the photoreceptor and substantially not transfer ink thereto; and in response to the detection, replace in the order of the colour separations the ID for the empty separation with a different ID.

2 . The apparatus of claim 1 wherein the selection of an ID for use in an empty separation is dependent on the time period for stabilising a voltage of an ID from the empty separation voltage to the colour separation voltage.

3 . The apparatus of claim 1 wherein the print controller comprises an imaging unit to manage print job requirements and to deliver print jobs to a main control node, MCN, for printing, the imaging unit being to:
receive in the imaging unit separations corresponding to spreads from a digital front end, DFE;
buffer separations corresponding to at least two spreads; and
configure print constraints based on the buffered spreads;
wherein a constraint may include inserting one or more empty separations into the colour separations of a spread.

4 . The apparatus of claim 3 wherein the imaging unit is to monitor the order of the colour separations in the buffer of separations corresponding to at least two spreads to selectively replace the ID of the empty separations in the buffer.

5 . The apparatus of claim 3 wherein the DFE comprises a memory to store printing jobs.

6 . The apparatus of claim 1 wherein the print controller comprises a main control node, MCN, to operate the printer to print jobs received from an imaging unit, the MCN being to:
maintain a pipeline of colour separations for printing print jobs received from the imaging unit; and
monitor the order of the colour separations in the pipeline to selectively replace the ID of the empty separations in the pipeline.

7 . The apparatus of claim 1 wherein the empty separation is a post-empty separation performed at the end of the spread;
wherein the colour separation at the beginning of the subsequent spread is considered when selecting an ID to use in the empty separation.

8 . The apparatus of claim 1 wherein the empty separation is a pre-empty separation performed at the beginning of the spread;
wherein the colour separation at the beginning of the spread is considered when selecting an ID to use in the empty separation.

9 . The apparatus of claim 1 wherein the empty separation is a white policy empty separation performed before and after a white colour separation;
wherein the next colour separation is considered when selecting an ID to use in the empty separation.

10 . A printer comprising the apparatus as claimed in claim 1 , the printer further comprising a writing head to selectively discharge areas of the photoreceptor to allow an image to be formed.

11 . The printer as claimed in claim 10 , the printer further comprising an image transfer blanket affixed to an intermediate transfer member, ITM, wherein the image transfer blanket is to receive ink from the photoreceptor and transfer it to the print medium supported by an impression drum, IMP.

12 . A non-transitory computer readable medium comprising instructions that when executed by at least one processor, cause the at least one processer to implement an apparatus for controlling a liquid electrophotography printer comprising a plurality of ink developers, IDs, to transfer charged ink to a photoreceptor, the apparatus comprising a print controller to, in use:
monitor an order of colour separations to be printed onto the print medium; detect in the order of colour separations an empty separation of an ID followed by a printing separation of the same ID, an empty separation representing a separation in which no image is formed on the photoreceptor and the engaged ID is at a voltage different to the voltage of the ID for a printing separation so as to, in the empty separation, substantially wet the photoreceptor and substantially not transfer ink thereto; and in response to the detection, replace in the order of the colour separations the ID for the empty separation with a different ID.

13 . A method for controlling a liquid electrophotography printer comprising a plurality of ink developers, IDs, to transfer charged ink to a photoreceptor, the method comprising:
monitoring an order of colour separations to be printed onto the print medium; detecting in the order of colour separations an empty separation of an ID followed by a printing separation of the same ID, an empty separation representing a separation in which no image is formed on the photoreceptor and the engaged ID is at a voltage different different to the voltage of the ID for a printing separation so as to, in the empty separation, substantially wet the photoreceptor and substantially not transfer ink thereto; and in response to the detection, replacing in the order of the colour separations the ID for the empty separation with a different ID.

14 . The method of claim 13 wherein the selection of an ID for use in an empty separation is dependent on the time period for stabilising a voltage of an ID from the empty separation voltage to the colour separation voltage.

15 . The method of claim 13 implemented in an imaging unit to manage print job requirements and to deliver print jobs to a main control node, MCN, for printing, the method further comprising:
receiving separations corresponding to spreads from a digital front end, DFE;
buffering colour separations corresponding to at least two spreads; and
configuring print constraints based on the buffered spreads;
wherein a constraint may include inserting one or more empty separations into the colour separations of a spread.

Assignees

• Hp Indigo Bv

Inventors

• Portnoy Vitaly
• Nachmias Yoav
• Assenheimer Michel
• Haim Liran Fanny

Classifications

• G03G21/0094

  fatigue treatment of the photoconductor · CPC title

• G03G15/50

  Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control (sequencing control G03G21/14) · CPC title

• G03G15/0121 Primary

  for developing · CPC title

• G03G15/101

  for wetting the recording material · CPC title

• G03G15/10 Primary

  using a liquid developer · CPC title