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US 8,712,292 B2Granted
Color image forming apparatus with contact control of process units
AssigneeCanon Kabushiki Kaisha
InventorNobuyuki Kobayashi
Life of this patent
Estimating the term…
Abstract
The color image forming apparatus performs registration control and is operable in first and second image forming modes. Contact control in the first image forming mode is different from that in the second image forming mode. The control section causes an alignment correction amount to vary between registration control corresponding to image forming for a second or subsequent sheet in the first image forming mode and registration control corresponding to image forming for a second or subsequent sheet in the second image forming mode. An engine control section causes a color deviation correction amount for contact control of a process unit when shifting from image forming for a first sheet to image forming for a second sheet to vary between the first and second image forming modes.
Claims21
A color image forming apparatus, comprising:
- a photosensitive member;
- a developing unit including a plurality of developing devices that develop electrostatic latent images formed on the photosensitive member with different color toners as a toner image;
- an image bearing member for transferring a toner image formed on the photosensitive member, or a conveyance member that conveys a sheet onto which the toner image is transferred;
- a control unit that performs a contact control in which one of the plurality of developing devices contacts with or separates from the photosensitive member and then an image formation after stand-by for a time period,
- wherein said color image forming apparatus is operable in a first image forming mode and in a second image forming mode, the contact control in the first image forming mode being different from the contact control in the second image forming mode, and
- wherein the control unit differentiates a correction amount for alignment in a registration control in the first image forming mode from a correction amount for alignment in the registration control in the second image forming mode.
3 more elements
A color image forming apparatus, comprising:
- a first process unit that includes a photosensitive member and an image bearing member for transferring a toner image formed on the photosensitive member, or a conveyance member that conveys a sheet onto which the toner image is transferred;
- a detection section that detects a mark formed on the image bearing member or the conveyance member, wherein according to a detection of the mark by the detection section, said color image forming apparatus performs contact control in which the first process unit contacts with a second process unit, or the second process unit is separated from a state in which the second process unit contacts with the first process unit to form a toner image on the image bearing member or the sheet, and image forming after stand-by for a time period, and said color image forming apparatus repeatedly performs the contact control and the image forming for each of sheets;
- and
- a control section that, when an image forming for a first sheet is performed, performs the contact control for the second process unit and also performs first registration control that corresponds to image forming for the first sheet according to the detection of the mark by the detection section, and when an image forming for a second or subsequent sheets is performed, performs the contact control for the second process unit and also performs second registration control that corresponds to image forming for the second or subsequent sheets according to the detection of the mark by the detection section,
- wherein said color image forming apparatus is operable in a first image forming mode and in a second image forming mode in which a conveyance speed of a sheet when a toner image is fixed onto the sheet is different from a conveyance speed of a sheet in the first image forming mode, the contact control in the first image forming mode being different from the contact control in the second image forming mode, and
- the control section differentiates a correction amount for an alignment in the second registration control in the first image forming mode from a correction amount for alignment in the second registration control in the second image forming mode.
3 more elements
A color image forming apparatus, comprising:
- a photosensitive member;
- a developing unit including a plurality of developing devices that develop electrostatic latent images formed on the photosensitive member with different color toners as a toner image;
- an image bearing member for transferring a toner image formed on the photosensitive member, or a conveyance member that conveys a sheet onto which the toner image is transferred;
- a detection unit that detects a mark formed on the image bearing member or the conveyance member, wherein according to a detection of the mark by the detection section, said color image forming apparatus performs contact control in which one of the plurality of developing devices contacts with the photosensitive member, or the one of the plurality of developing devices is separated from a state in which the developing device contacts with the photosensitive member to form a toner image on the photosensitive member, and image forming after stand-by for a time period, and said color image forming apparatus repeatedly performs the contact control and the image forming for each of sheets;
- and
- a control unit that, when an image forming for a first sheet is performed, performs the contact control for the one of the plurality of developing devices and also performs first registration control that corresponds to image forming for the first sheet according to the detection of the mark by the detection unit, and when an image forming for a second or subsequent sheets is performed, performs the contact control for the one of the plurality of developing devices and also performs second registration control that corresponds to image forming for the second or subsequent sheets according to the detection of the mark by the detection unit,
- wherein said color image forming apparatus is operable in a first image forming mode and in a second image forming mode, the contact control in the first image forming mode being different from the contact control in the second image forming mode, and
- wherein the control unit differentiates a correction amount for alignment in the second registration control in the first image forming mode from a correction amount for alignment in the second registration control in the second image forming mode.
5 more elements
Dependencies are inferred from the claim text.