Image forming apparatus and adjusting method

Patent metadata

Field	Value
Publication number	US-11366404-B2
Application number	US-202117226156-A
Country	US
Kind code	B2
Filing date	Apr 9, 2021
Priority date	Apr 23, 2020
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

An image forming apparatus includes an image bearer, a transfer rotator, an adjuster, and circuitry. The image bearer bears a toner image. The transfer rotator contacts the image bearer to form a transfer nip between the transfer rotator and the image bearer. The transfer rotator transfers the toner image from the image bearer onto a sheet conveyed to the transfer nip. The adjuster adjusts at least one of a relative difference in linear velocity of the transfer rotator to the image bearer at the transfer nip and a relative contact pressure of the transfer rotator to the image bearer at the transfer nip. Based on a difference in image magnification, in a direction of conveyance of the sheet, of toner images transferred onto surfaces of one or more sheets conveyed to the transfer nip, the circuitry causes the adjuster to reduce the difference in image magnification.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an image bearer configured to bear a toner image;
a transfer rotator configured to contact the image bearer to form a transfer nip between the transfer rotator and the image bearer,
the transfer rotator being configured to transfer the toner image from the image bearer onto a sheet conveyed to the transfer nip;
an adjuster configured to adjust at least one of a relative difference in linear velocity of the transfer rotator to the image bearer at the transfer nip and a relative contact pressure of the transfer rotator to the image bearer at the transfer nip;
circuitry configured to, based on a difference in image magnification, in a direction of conveyance of the sheet, of toner images transferred onto surfaces of one or more sheets conveyed to the transfer nip, cause the adjuster to reduce the difference in image magnification; and
a detector,
wherein the detector is configured to detect, as a first distance, a distance between detection marks on a first sheet in a direction of conveyance of the first sheet, the detection marks being transferred onto different positions from each other in the direction of conveyance of the first sheet, the first sheet bearing a first image pattern transferred,
wherein the detector is configured to detect, as a second distance, a distance between the detection marks on a second sheet in a direction of conveyance of the second sheet, the detection marks being transferred onto different positions from each other in the direction of conveyance of the second sheet to be located identically to the detection marks on the first sheet, the second sheet bearing a second image pattern transferred, the second image pattern having an image area rate greater than an image area rate of the first image pattern, and
wherein the circuitry is configured to cause the adjuster to adjust a difference in distance between the first distance and the second distance detected by the detector to be equal to or less than a given value.

2. The image forming apparatus according to claim 1 ,
wherein the image area rate of the first image pattern is 0%, and
wherein the image area rate of the second image pattern is 25% or greater.

3. The image forming apparatus according to claim 1 , further comprising a sheet reversal device configured to convey the sheet bearing the toner image, which has been transferred onto a front side of the sheet, toward the transfer nip to transfer another toner image from the image bearer onto a back side of the sheet at the transfer nip,
wherein the first sheet and the second sheet are the front side and the back side, respectively, of the sheet as a single sheet,
wherein the first image pattern is formed on the front side of the single sheet, and
wherein the second image pattern is formed on the back side of the single sheet.

4. The image forming apparatus according to claim 1 ,
wherein the adjuster is configured to adjust at least one of a rotational speed of the transfer rotator and a contact pressure of the transfer rotator against the image bearer, and
wherein the circuitry is configured to cause the adjuster to:
increase at least one of the rotational speed and the contact pressure in a case in which the difference in distance exceeds the given value and in a case in which the first distance is greater than the second distance; and
decrease at least one of the rotational speed and the contact pressure in a case in which the difference in distance exceeds the given value and in a case in which the first distance is equal to or less than the second distance.

5. The image forming apparatus according to claim 1 , further comprising:
a display,
wherein the circuitry is configured to display a warning on the display in a case in which the difference in distance is not equal to or less than the given value after the circuitry executes a given number of times of an adjustment mode to control the adjuster based on the difference in distance.

6. The image forming apparatus according to claim 1 , wherein the circuitry is configured to cause the adjuster to:
adjust the contact pressure in a case in which the difference in image magnification is greater than a given amount; and
adjust the difference in linear velocity in a case in which the difference in image magnification is equal to or less than the given amount.

7. The image forming apparatus according to claim 1 , further comprising an exposure device configured to emit light and write a latent image,
wherein the circuitry is configured to adjust a writing timing and an exposure distribution of the exposure device for each of a main scanning direction and a sub-scanning direction after the circuitry executes an adjustment mode to control the adjuster.

8. The image forming apparatus according to claim 1 , wherein at least one of the image bearer and the transfer rotator is an elastic belt.

9. An adjustment method for an image forming apparatus, the image forming apparatus including an image bearer, a transfer rotator configured to contact the image bearer to form a transfer nip between the transfer rotator and the image bearer, and an adjuster, the method comprising:
transferring a first toner image and a second toner image having an image area rate different from an image area rate of the first toner image onto a front side and a back side, respectively, of a sheet conveyed to the transfer nip or onto a surface of a first sheet and a surface of a second sheet, respectively, the first sheet and the second sheet being conveyed to the transfer nip;
causing, based on a difference in image magnification, in a direction of conveyance of the sheet or in a direction of conveyance of the first sheet and the second sheet, of the first toner image and the second toner image on the front side and the back side, respectively, of the sheet or on the surface of the first sheet and the surface of the second sheet, respectively, the adjuster to reduce the difference in image magnification;
detecting, as a first distance, a distance between detection marks on the first sheet in a direction of conveyance of the first sheet, the detection marks being transferred onto different positions from each other in the direction of conveyance of the first sheet, the first sheet bearing a first image pattern transferred;
detecting, as a second distance, a distance between the detection marks on the second sheet in a direction of conveyance of the second sheet, the detection marks being transferred onto different positions from each other in the direction of conveyance of the second sheet to be located identically to the detection marks on the first sheet, the second sheet bearing a second image pattern transferred, the second image pattern having an image area rate greater than an image area rate of the first image pattern; and
adjusting a difference in distance between the first distance and the second distance to be equal to or less than a given value.

10. The method according to claim 9 , wherein:
the image area rate of the first image pattern is 0%, and
the image area rate of the second image pattern is 25% or greater.

11. The method according to claim 9 , wherein:
the first sheet and the second sheet are the front side and the back side, respectively, of the sheet as a single sheet,
the first image pattern is formed on the front side of the single sheet, and
the second image pattern is formed on the back side of the single sheet.

12. The method according to claim 9 , further comprising:
adjusting, by the adjuster, at least one of a rotational speed of the transfer rotator and a contact pressure of the transfer rotator ag

Assignees

• Ricoh Co Ltd

Inventors

• Nakamoto Atsushi
• Kogure Seiichi
• Hamada Daisuke
• Akiyama Takuya
• Aoki Yuuki
• Goto Yutaka

Classifications

• G03G15/0415 Primary

  and means for controlling illumination or exposure · CPC title

• G03G15/168

  with means for conditioning the transfer element, e.g. cleaning · CPC title

• G03G2215/00949

  Copy material feeding speed switched according to current mode of the apparatus, e.g. colour mode · CPC title

• G03G15/1615

  relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning · CPC title

• G03G15/167

  at least one of the recording member or the transfer member being rotatable during the transfer · CPC title