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US 2009/0214241 A1Published application
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsHiroshi Kawaguchi, Hisashi Enomoto
Life of this patent
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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.
Claims9
An image forming apparatus, comprising:
- a rotary member onto which toner images formed on a plurality of image bearing members are transferred;
- developing devices capable of coming into contact with and separating from the respective image bearing members, the developing devices forming the toner images on the respective image bearing members;
- a patch detector configured to detect positions of toner patches, the toner patches being transferred onto the rotary member from the image bearing members and forming a toner patch pattern;
- and
- a control device configured to control a peripheral velocity of the rotary member or a peripheral velocity of the image bearing members based on a detection result obtained by the patch detector,
- wherein the toner patch pattern on the rotary member includes a first toner patch transferred onto the rotary member from one of the image bearing members while all of the developing devices are in contact with the respective image bearing members and a second toner patch transferred onto the rotary member from another one of the image bearing members while one or more of the developing devices are in contact with or separated from the respective image bearing members,
- wherein the patch detector detects positions of the first and second toner patches included in the toner patch pattern,
- wherein a displacement between the first toner patch and the second toner patch in a rotational direction of the rotary member is calculated based on the detection result obtained by the patch detector, and
- wherein the peripheral velocity of the rotary member or the peripheral velocity of the image bearing members is changed based on the calculated displacement.
6 more elements
An image forming apparatus, comprising:
- a rotary member onto which toner images formed on a plurality of image bearing members are transferred;
- developing devices capable of coming into contact with and separating from the respective image bearing members, the developing devices forming the toner images on the respective image bearing members;
- a patch detector configured to detect positions of toner patches, the toner patches being transferred onto the rotary member from the image bearing members and forming a first toner patch pattern and a second toner patch pattern;
- and
- a control device configured to control a peripheral velocity of the rotary member or a peripheral velocity of the image bearing members based on a detection result obtained by the patch detector,
- wherein the first toner patch pattern includes a plurality of first toner patches transferred onto the rotary member from the image bearing members while all of the developing devices are in contact with the respective image bearing members, the patch detector detects positions of the first toner patches included in the first toner patch pattern, and a first displacement between the first toner patches in a rotational direction of the rotary member is calculated based on the detection result obtained by the patch detector,
- wherein the second toner patch pattern includes a first toner patch transferred onto the rotary member from one of the image bearing members while all of the developing devices are in contact with the respective image bearing members and a second toner patch transferred onto the rotary member from another one of the image bearing members while one or more of the developing devices are in contact with or separated from the respective image bearing members, the patch detector detects positions of the first and second toner patches, and a second displacement between the first and second toner patches in the rotational direction of the rotary member is calculated based on the detection result obtained by the patch detector, and
- wherein the peripheral velocity of the rotary member or the peripheral velocity of the image bearing members is changed based on a difference between the second displacement and the first displacement.
5 more elements
Dependencies are inferred from the claim text.