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US 8,712,266 B2Granted
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsHiroshi Kawaguchi, Hisashi Enomoto
Life of this patent
Estimating the term…
Abstract
In the case where a peripheral velocity of photosensitive drums differs from a peripheral velocity of an intermediate transfer belt, the peripheral velocity of the intermediate transfer belt or the peripheral velocity of the photosensitive drums is corrected. The velocity of the intermediate transfer belt is transiently varied in an image forming operation. Accordingly, a plurality of tonner patch patterns including toner patches are formed on the intermediate transfer belt, and the difference in peripheral velocity between the intermediate transfer belt and the photosensitive drums is estimated based on a difference between the displacements in the tonner patch patterns.
Claims21
An image forming apparatus, comprising:
- a first image bearing member configured to bear a toner image:
- a first developing device capable of coming into contact with and separating from the first image bearing member and configured to form a toner image on the first image bearing member;
- a second image bearing member configured to bear a toner image;
- a second developing device capable of coming into contact with and separating from the second image bearing member and configured to form a toner image on the second image bearing member;
- a rotary member onto which the toner images are transferred from the first and second image bearing members or configured to convey a recording medium onto which the toner images are transferred, the rotary member coming into contact with the first and second image bearing members so that the rotary member forms transfer sections with the first and second image bearing members, respectively;
- a patch detector configured to detect a toner patch transferred onto the transfer member from the first and second image bearing members;
- and
- a control device configured to control a relative velocity between the rotary member and the first and second image bearing members,
- wherein the image forming apparatus is capable of forming first and second toner patch patterns on the rotary member, the first toner patch pattern including a first toner patch to be transferred from the first image bearing member to the rotary member and a second toner patch to be transferred from the second image bearing member to the rotary member while the first and second developing devices are in contact with the first and second image bearing members, respectively, and the second toner patch pattern including a third toner patch to be transferred from the first image bearing member to the rotary member while the first and second developing devices are in contact with the first and second image bearing members, respectively, and a fourth toner patch to be transferred from the second image bearing member to the rotary member while the first developing device is separated from the first image bearing member and the second developing device is in contact with the second image bearing member, and
- wherein the control device controls the relative velocity between the rotary member and the first and second image bearing members based on detection results of detecting the first and second toner patch patterns by the patch detector.
7 more elements
An image forming apparatus, comprising:
- first and second image bearing members;
- a first developing device configured to come into contact with and separating from the first image bearing member;
- a second developing device configured to come into contact with and separating from the second image bearing member;
- the first image bearing member configured to bear a toner image formed by toner from the first developing device coming into contact with the first image bearing member;
- the second image bearing member configured to bear a toner image formed by toner from the second developing device coming into contact with the second image bearing member;
- a rotary member onto which the toner images are transferred from the first and second image bearing members or configured to convey a recording medium onto which the toner images are transferred, the rotary member coming into contact with the first and second image bearing members so that the rotary member forms transfer sections with the first and second image bearing members, respectively;
- a patch detector configured to detect a toner patch transferred onto the rotary member from the first and second image bearing members;
- and
- a control device configured to control a relative velocity between the rotary member and the first and second image bearing members,
- wherein the patch detector detects a first toner patch transferred onto the rotary member while the toner is present at the transfer sections formed by the rotary member with the first and second image bearing members, respectively,
- wherein the patch detector detects a second toner patch transferred onto the rotary member while the toner is present at one of the transfer sections formed by the rotary member with the first and second image bearing members, and the toner is not present at the other of the transfer sections formed by the rotary member with the first and second image bearing members,
- wherein the toner is not present at the other of the transfer sections due to the first or second image bearing member, which forms the other of the transfer sections, being separated from the respective developing device, and
- wherein the control device corrects the relative velocity between the rotary member and the first and second image bearing members based on the result of detection of the first and second toner patches by the patch detector.
10 more elements
An image forming apparatus comprising:
- first and second image bearing members, an electrostatic latent image being formed on each of the first and second image bearing members, configured to bear a toner image by being supplied with toner from a corresponding developing device and the electrostatic latent image being developed;
- a rotary member onto which the toner images are transferred from the first and second image bearing members or configured to convey a recording medium onto which the toner images are transferred, the rotary member coming into contact with the first and second image bearing members so that the rotary member forms transfer sections with the first and second image bearing members, respectively;
- a patch detector configured to detect a toner patch transferred onto the rotary member from the first and second image bearing members;
- and
- a control device configured to control a relative velocity between the rotary member and the first and second image bearing members,
- wherein the patch detector detects a first toner patch transferred onto the rotary member while adhering toner is present at the transfer sections formed by the rotary member with the first and second image bearing members, respectively,
- wherein the patch detector detects a second toner patch transferred onto the rotary member while adhering toner is present at one of the transfer sections formed by the rotary member with the first and second image bearing members, and adhering toner is not present at the other transfer section,
- wherein the adhering toner adheres to the image bearing member irrespective of the electrostatic latent image, and
- wherein the control device corrects the relative velocity between the rotary member and the first and second image bearing members based on the result of detection of the first and second toner patches by the patch detector.
6 more elements
Dependencies are inferred from the claim text.