Image forming apparatus and method of correcting positional deviation of sheet

Patent metadata

Field	Value
Publication number	US-11235597-B2
Application number	US-201916257179-A
Country	US
Kind code	B2
Filing date	Jan 25, 2019
Priority date	Feb 8, 2018
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

An image forming apparatus, in which a method of correcting a positional deviation of a sheet is performed, includes a detecting device to detect a position of the sheet, a pair of sheet conveying bodies to convey the sheet and correct the positional deviation of the sheet, an image forming device to form an image on the sheet, and circuitry to calculate a first positional deviation amount of the sheet based on a first detection result of the detecting device, cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the first positional deviation amount, calculate a second positional deviation amount of the sheet based on a second detection result of the detecting device, and cause the image forming device to correct the positional deviation of an image forming position on the sheet based on the second positional deviation amount.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a detecting device configured to detect a position of a sheet;
a pair of sheet conveying bodies configured to convey the sheet and correct a positional deviation of the sheet;
an image forming device configured to form an image on the sheet; and
circuitry configured to:
calculate a first positional deviation amount of the sheet based on a first detection result of the position of the sheet by the detecting device;
cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the first positional deviation amount;
calculate a second positional deviation amount of the sheet based on a second detection result of the position of the sheet by the detecting device; and
cause the image forming device to correct a positional deviation of an image forming position on the sheet based on the second positional deviation amount,
wherein the circuitry is further configured to cause the image forming device to correct the positional deviation of the image forming position in a width direction of the sheet,
wherein the image forming device includes a plurality of ink discharging nozzles from which liquid is discharged onto the sheet to form an image on the sheet, and
wherein the circuitry is further configured to:
generate image data of an image to be formed on the sheet by the image forming device;
generate ink discharge data used to determine allocation of the plurality of ink discharging nozzles to discharge the liquid onto the sheet based on the image data;
slide the allocation of the plurality of ink discharging nozzles determined based on the ink discharge data in the width direction of the sheet; and
cause the image forming device to correct the positional deviation of the image forming Position on the sheet in the width direction of the sheet.

2. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to:
generate image data of an image to be formed on the sheet by the image forming device;
change the image data; and
cause the image forming device to correct the image forming position on the sheet based on the image data changed.

3. The image forming apparatus according to claim 1 ,
wherein the circuitry is configured to cause the image forming device to correct the image forming position in a rotation direction of the sheet within a plane of sheet conveyance of the sheet.

4. The image forming apparatus according to claim 1 ,
wherein the detecting device includes a plurality of contact image sensors arranged along a sheet conveying direction of the sheet.

5. The image forming apparatus according to claim 4 ,
wherein the plurality of contact image sensors includes an extreme downstream contact image sensor and a second extreme downstream contact image sensor,
wherein the circuitry is configured to:
cause the second extreme downstream contact image sensor and the extreme downstream contact image sensor to detect the position of the sheet when a trailing end of the sheet passes the second extreme downstream contact image sensor;
calculate a positional deviation amount of the sheet based on detection results of the second extreme downstream contact image sensor and the extreme downstream contact image sensor; and
cause the image forming device to correct the image forming position on the sheet based on the positional deviation amount of the sheet.

6. The image forming apparatus according to claim 4 ,
wherein the plurality of contact image sensors includes an extreme downstream contact image sensor,
wherein the image forming device is configured to correct the image forming position on the sheet in a width direction of the sheet,
wherein the circuitry is configured to:
cause the extreme downstream contact image sensor to detect the position of the sheet when a trailing end of the sheet passes the extreme downstream contact image sensor;
calculate a positional deviation amount in the width direction of the sheet based on a detection result of the extreme downstream contact image sensor; and
cause the image forming device to correct the image forming position on the sheet based on the positional deviation amount of the sheet.

7. The image forming apparatus according to claim 1 ,
wherein the detecting device includes an image capturing device configured to capture an image of at least a portion of the sheet, and
wherein the circuitry is configured to:
calculate at least one of the first positional deviation amount and the second positional deviation amount of the sheet based on the image of at least the portion of the sheet captured by the image capturing device; and
cause the image forming device to correct the image forming position on the sheet based on the at least one of the first positional deviation amount and the second positional deviation amount of the sheet.

8. The image forming apparatus according to claim 1 , wherein the positional deviation of the image forming position on the sheet is correctable by at least one of changing ink discharging data of at least one of the ink discharging nozzles and changing the image data.

9. The image forming apparatus, comprising:
a detecting device configured to detect a position of a sheet, the detecting device including a plurality of contact image sensors arranged along a sheet conveying direction of the sheet;
a pair of sheet conveying bodies configured to convey the sheet and correct a positional deviation of the sheet;
an image forming device configured to form an image on the sheet; and
circuitry configured to:
calculate a first positional deviation amount of the sheet based on a first detection result of the position of the sheet by the detecting device;
cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the first positional deviation amount;
calculate a second positional deviation amount of the sheet based on a second detection result of the position of the sheet by the detecting device; and

cause the image forming device to correct a positional deviation of an image forming position on the sheet based on the second positional deviation amount,
wherein the plurality of contact image sensors includes a first contact image sensor, a second contact image sensor, and a third contact image sensor disposed from an upstream side to a downstream side of the sheet conveying direction,
wherein the circuitry is configured to:
cause the first contact image sensor and the second contact image sensor to detect the position of the sheet;
calculate the first positional deviation amount of the sheet based on detection results of the position of the sheet by the first contact image sensor and the second contact image sensor;
cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the t positional deviation amount;
cause the second contact image sensor and the third contact image sensor to detect the position of the sheet;
calculate the second positional deviation amount of the sheet based on detection results of the position of the sheet by the second contact image sensor and the third contact image sensor; and
cause the pair of sheet conveying bodies to perform re-correction of the positional deviation of the sheet based on said second positional deviation amount, and

wherein the circuitry is configured to perform a feedback control during the re-correction.

10. A method of correcting a positional deviation of a sheet, the method comprising:
detecting a position of the sheet by at least one of an image capturing device and a plurality of image sensors;
calculating a first positional devia

Assignees

• Kaneko Takaaki
• Takahashi Motoharu
• Maeyama Yuichiro
• Egawa Tomohiro
• Ricoh Co Ltd

Inventors

• Kaneko Takaaki
• Takahashi Motoharu
• Maeyama Yuichiro
• Egawa Tomohiro

Classifications

• B41J11/008 Primary

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

• B65H5/062

  between rollers or balls · CPC title

• B65H2404/14212

  rotating, pivoting or oscillating around an axis perpendicular to the roller axis · CPC title

• B41J13/0018

  in the sheet input section of automatic paper handling systems · CPC title

• B65H9/10

  Pusher and like movable registers; Pusher or gripper devices which move articles into registered position · CPC title