Buffer unit

Patent metadata

Field	Value
Publication number	US-11679604-B2
Application number	US-201716755615-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Dec 13, 2017
Publication date	Jun 20, 2023
Grant date	Jun 20, 2023

Abstract

Certain examples described herein relate to a buffer unit for a printing system. In certain cases, a measurement device is used to obtain measurement data representing an optical property of a printed image on a substrate. A buffer unit receives the substrate downstream of the measurement device and places the substrate in a queue. In certain cases, a controller determines, based on the measurement data, whether the printed image comprises a defect. Responsive to determining that the printed image does not comprise a defect, the controller causes the substrate to be moved from the buffer unit to an output stack. Responsive to determining that the printed image comprises a defect, the controller causes the substrate to not be moved to the output stack.

First claim

What is claimed is:

1. An apparatus comprising:
a measurement device to obtain measurement data representing an optical property of a printed image on a first substrate;
a buffer unit to receive the first substrate downstream of the measurement device and place the first substrate in a queue; and
a controller to:
determine, based on the measurement data, whether the printed image comprises a defect;
responsive to determining that the printed image does not comprise a defect, cause the first substrate to be moved from the buffer unit to an output stack; and
responsive to determining that the printed image comprises a defect, cause the first substrate to not be moved to the output stack.

2. The apparatus of claim 1 , wherein the buffer unit is operable to hold a plurality of substrates in the queue in a pre-configured order.

3. The apparatus of claim 1 , comprising a printing mechanism upstream of the measurement device to generate the printed image on the first substrate, wherein the printing mechanism is a variable-data printing mechanism.

4. The apparatus of claim 1 , wherein, responsive to determining that the printed image comprises a defect, the controller is to output a control signal to a printing mechanism to cause the printing mechanism to re-print the printed image on a second substrate; and
comprising a buffer bypass to receive the second substrate, the buffer bypass arranged in parallel with the queue to allow the second substrate to bypass the queue,
wherein the controller is to:
determine whether the re-printed image comprises a defect;
responsive to determining that the re-printed image does not comprise a defect,
cause the second substrate to be moved from the buffer bypass to the output stack; and
responsive to determining that the re-printed image comprises a defect, cause the second substrate to not be moved to the output stack.

5. A method comprising:
receiving measurement data from a sensor, the measurement data indicating a measured property of a printed image on a first print medium;
placing the first print medium in a buffer downstream of the sensor, the buffer comprising a plurality of further print media held in a queue;
determining, based on the measurement data, whether the printed image comprises a defect;
responsive to determining that the printed image does not comprise a defect, transferring the first print medium from the buffer to an output stack; and
responsive to determining that the printed image comprises a defect, discarding the first print medium.

6. The method of claim 5 , comprising, responsive to determining that the printed image comprises a defect, outputting a control signal to a printing mechanism to cause the printing mechanism to re-print the printed image on a second print medium.

7. The method of claim 6 , comprising placing the second print medium comprising the re-printed image at the front of the queue.

8. The method of claim 6 , comprising causing the second print medium comprising the re-printed image to bypass the buffer.

9. The method of claim 6 , comprising preventing the further plurality of print media from leaving the buffer until a determination is made on whether the re-printed image comprises a defect.

10. The method of claim 6 , comprising outputting a control signal to the printing mechanism to defer printing of a further image until a determination is made on whether the re-printed image comprises a defect.

11. The method of claim 6 , comprising:
receiving further measurement data from the sensor, the further measurement data indicating a measured property of the re-printed image;
determining, based on the further measurement data, whether the re-printed image comprises a defect;
responsive to determining that the re-printed image does not comprise a defect, transporting the second print medium to the output stack; and
responsive to determining that the re-printed image comprises a defect, discarding the second print medium.

12. A buffer unit to receive items of print media, and signals indicating whether respective items of print media are defective or not, from a printing system, the buffer unit comprising:
a media retainer to receive a first print medium comprising a printed image and hold the first print medium in a queue; and
a first diverter to control a media path downstream of the media retainer, the first diverter being controllable to:
if the printed image is defective, cause the first print medium to bypass an output stack; and
if the printed image is not defective, direct the first print medium to the output stack; and

a second diverter to control a media path upstream of the media retainer, the second diverter being configured to cause a second print medium comprising a re-printed image to bypass the media retainer and direct the second print medium to the first diverter, the re-printed image corresponding to a defective printed image.

13. The buffer unit of claim 12 , wherein the media retainer is operable to hold a plurality of print media in the queue in a pre-configured order.

Assignees

• Hewlett Packard Development Co

Inventors

• Koloditsky Yechiam

Classifications

• G06T7/001

  using an image reference approach · CPC title

• B65H43/04

  detecting, or responding to, presence of faulty articles (B65H43/08 takes precedence; diverting faulty articles from main streams B65H29/62) · CPC title

• B41J11/44 Primary

  by devices, e.g. program tape or contact wheel, moved in correspondence with movement of paper-feeding devices, e.g. platen rotation · CPC title

• B65H2301/4213

  of a limited number of articles, e.g. buffering, forming bundles · CPC title

• B41J11/425

  for a variable printing material feed amount · CPC title