Liquid discharge apparatus

Patent metadata

Field	Value
Publication number	US-10792912-B2
Application number	US-201916294405-A
Country	US
Kind code	B2
Filing date	Mar 6, 2019
Priority date	Mar 15, 2018
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

A liquid discharge apparatus includes a rotator, a liquid discharger, a sheet-material position detector, a first signal output device, a second signal output device, and circuitry. The rotator carries a sheet material on a circumferential surface and conveys the sheet material. The liquid discharger discharges liquid onto the sheet material. The sheet-material position detector detects a position of the sheet material. The first signal output device outputs a first signal corresponding to a rotation amount of the rotator. The second signal output device outputs a second signal correlated with a movement amount of the sheet material on the circumferential surface of the rotator. The circuitry determines a discharge start timing of the liquid discharger from a detection result of the sheet-material position detector and the first signal, and generates a discharge timing of the liquid discharger from the second signal.

First claim

The invention claimed is:

1. A liquid discharge apparatus comprising:
a cylindrical rotator to carry a sheet material on a circumferential surface of the cylindrical rotator and convey the sheet material;
a liquid discharger facing the circumferential surface to discharge liquid onto the sheet material;
a sheet-material position detector to detect a position of the sheet material;
a first signal output device to output a first signal corresponding to a rotation amount of the cylindrical rotator;
a second signal output device to output a second signal correlated with a movement amount of the sheet material on the circumferential surface of the cylindrical rotator,
wherein the second signal output device comprises an encoder scale provided on the circumferential surface of the cylindrical rotator, and an encoder sensor arranged in a vicinity of the liquid discharger and reading the encoder scale, and
wherein L>L 1 +L 2 is satisfied, where L is a length of the encoder scale, L 1 is a maximum length of the sheet material that can be carried, and L 2 is a length of a discharge region of the liquid discharger, in a conveyance direction; and
circuitry to determine a discharge start timing of the liquid discharger from a detection result of the sheet-material position detector and the first signal, and generate a discharge timing of the liquid discharger from the second signal.

2. The liquid discharge apparatus according to claim 1 , further comprising a plurality of liquid dischargers including the liquid discharger,
wherein the encoder sensor is arranged in vicinity of each of the liquid dischargers.

3. The liquid discharge apparatus according to claim 1 , further comprising a plurality of encoder scales including the encoder scale,
wherein the plurality of encoder scales is arranged on the circumferential surface of the cylindrical rotator.

4. The liquid discharge apparatus according to claim 1 ,
wherein a reading position of the encoder sensor is on an upstream side from a discharge region upstream end of the liquid discharger in a conveyance direction, and
wherein a tip end of the encoder scale is located on a downstream side from a position on the upstream side in the conveyance direction by a distance between the reading position and the discharge region upstream end, with respect to a tip end carrying position of the sheet material.

5. The liquid discharge apparatus according to claim 1 ,
wherein a reading position of the encoder sensor is on a downstream side from a discharge region upstream end of the liquid discharger in a conveyance direction, and
wherein a tip end of the encoder scale is located on a downstream side in the conveyance direction by a distance longer than a distance between the reading position and the discharge region upstream end, with respect to a tip end carrying position of the sheet material.

6. The liquid discharge apparatus according to claim 1 ,
wherein the first signal output device comprises an encoder wheel provided on a shaft of the cylindrical rotator, and an encoder sensor to read the encoder wheel.

7. The liquid discharge apparatus according to claim 1 ,
wherein the sheet-material position detector detects a tip end of the sheet material.

8. The liquid discharge apparatus according to claim 1 ,
wherein the sheet-material position detector detects a mark provided on the sheet material.

9. A liquid discharge apparatus comprising:
a cylindrical rotator to carry a sheet material on a circumferential surface of the cylindrical rotator and convey the sheet material;
a liquid discharger facing the circumferential surface to discharge liquid onto the sheet material;
a sheet-material position detector to detect a position of the sheet material;
a first signal output device to output a first signal corresponding to a rotation amount of the cylindrical rotator;
a second signal output device to output a second signal correlated with a movement amount of the sheet material on the circumferential surface of the cylindrical rotator,
wherein the second signal output device comprises an encoder scale provided on the circumferential surface of the cylindrical rotator, and an encoder sensor arranged in a vicinity of the liquid discharger and reading the encoder scale,
wherein a reading position of the encoder sensor is on an upstream side from a discharge region upstream end of the liquid discharger in a conveyance direction, and
wherein a tip end of the encoder scale is located on a downstream side from a position on the upstream side in the conveyance direction by a distance between the reading position and the discharge region upstream end, with respect to a tip end carrying position of the sheet material; and
circuitry to determine a discharge start timing of the liquid discharger from a detection result of the sheet-material position detector and the first signal, and generate a discharge timing of the liquid discharger from the second signal.

10. The liquid discharge apparatus according to claim 9 , further comprising a plurality of liquid dischargers including the liquid discharger,
wherein the encoder sensor is arranged in vicinity of each of the liquid dischargers.

11. The liquid discharge apparatus according to claim 9 , further comprising a plurality of encoder scales including the encoder scale,
wherein the plurality of encoder scales is arranged on the circumferential surface of the cylindrical rotator.

12. The liquid discharge apparatus according to claim 9 ,
wherein a reading position of the encoder sensor is on an upstream side from a discharge region downstream end of the liquid discharger in the conveyance direction, and
wherein a rear end of the encoder scale is located on an upstream side in the conveyance direction by a distance longer than the distance between the reading position and the discharge region downstream end, with respect to a rear end carrying position of the sheet material.

13. The liquid discharge apparatus according to claim 9 ,
wherein the first signal output device comprises an encoder wheel provided on a shaft of the cylindrical rotator, and an encoder sensor to read the encoder wheel.

14. The liquid discharge apparatus according to claim 9 ,
wherein the sheet-material position detector detects a tip end of the sheet material.

15. The liquid discharge apparatus according to claim 9 ,
wherein the sheet-material position detector detects a mark provided on the sheet material.

16. A liquid discharge apparatus comprising:
a cylindrical rotator to carry a sheet material on a circumferential surface of the cylindrical rotator and convey the sheet material;
a liquid discharger facing the circumferential surface to discharge liquid onto the sheet material;
a sheet-material position detector to detect a position of the sheet material;
a first signal output device to output a first signal corresponding to a rotation amount of the cylindrical rotator;
a second signal output device to output a second signal correlated with a movement amount of the sheet material on the circumferential surface of the cylindrical rotator,
wherein the second signal output device comprises an encoder scale provided on the circumferential surface of the cylindrical rotator, and an encoder sensor arranged in a vicinity of the liquid discharger and reading the encoder scale,
wherein a reading position of the encoder sensor is on a downstream side from a discharge region upstream end of the liquid discharger in a conveyance direction, and
wherein a tip end of the encoder scale is located on a downstream side in

Assignees

• Maeyama Yuichiro
• Horie Yasuyuki
• Ricoh Co Ltd

Inventors

• Maeyama Yuichiro
• Horie Yasuyuki

Classifications

• B41J11/0095 Primary

  Detecting means for copy material, e.g. for detecting or sensing presence of copy material or its leading or trailing end · CPC title

• B41J13/223

  on rotatable drums · CPC title

• B41J11/008

  Controlling printhead for accurately positioning print image on printing material, e.g. with the intention to control the width of margins · CPC title

• B41J11/0045

  Guides for printing material (curl smoothing B41J11/0005; platens B41J11/02, B41J11/06; guiding webs B41J15/046) · CPC title

• B41J11/42

  Controlling {printing material conveyance for accurate alignment of the printing material with the printhead; Print registering} · CPC title