Image forming apparatus having misregistration correction

Patent metadata

Field	Value
Publication number	US-9291932-B2
Application number	US-201213679088-A
Country	US
Kind code	B2
Filing date	Nov 16, 2012
Priority date	Dec 1, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

An image forming apparatus includes a plurality of image forming devices having a developing device that develops an electrostatic latent image formed on an image bearing member to form a toner image, and a transferring device that transfers the developed toner image to an intermediate transfer member or a transfer material, for each of a plurality of colors, an exposure unit that irradiates the image bearing member with a laser beam to form the electrostatic latent image on the image bearing member, and a detector that detects an image pattern for correcting misregistration of each color. In addition, a control device corrects the misregistration of each color based on a detection result by the detector. The control device forms an image pattern of one color among the plurality of colors on a first page interval that is between a first image and a second image, and corrects misregistration based on a first period from a timing when a reference signal to form the image pattern of one color among the plurality of colors is transmitted to a timing when the image pattern of one color among the plurality of colors is detected by the detector.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
a plurality of image forming devices, each including a developing device that develops an electrostatic latent image formed on an image bearing member to form a toner image, and a transferring device that transfers the toner image developed by the developing device to an intermediate transfer member or a transfer material conveyed by a transfer material conveyance member, for each of a plurality of colors;
an exposure unit that irradiates the image bearing members with a laser beam to form the electrostatic latent image on the image bearing members;
a detector that detects an image pattern for correcting misregistration of each color, the image pattern formed on the intermediate transfer member or the conveyed transfer material; and
a control device that corrects the misregistration of each color based on a detection result by the detector,
wherein the control device performs control to form an image pattern of at least one color among the plurality of colors but not all of the plurality of colors on a first page interval in an image forming area that is between a first image and a second image formed subsequently to the first image, and corrects misregistration based on a first period from a timing when a reference signal to form the image pattern of the at least one color among the plurality of colors is transmitted to a timing when the image pattern of the at least one color among the plurality of colors is detected by the detector,
wherein the control device performs control to form an image pattern of another color different from the at least one color among the plurality of colors on a second page interval different from the first page interval, and corrects misregistration based on the first period and a second period from a timing when a reference signal to form the image pattern of the other color is transmitted to a timing when the image pattern of the other color is detected by the detector.

2. An image forming apparatus according to claim 1 , wherein the control device performs control to form an image pattern of a single color among the plurality of colors on the first page interval, and corrects misregistrations of the plurality of colors based on a reference period from a timing when a reference signal to form the image pattern of the single color among the plurality of colors is transmitted to a timing when the image pattern of the single color among the plurality of colors is detected by the detector.

3. An image forming apparatus according to claim 2 ,
wherein the control device performs control to form a reference pattern of a plurality of colors for obtaining the reference period for correcting the misregistration before the first image is formed, obtains the reference period for correcting the misregistration from a detection result of the reference pattern of the plurality of colors, and
corrects the misregistration based on the first period and the reference period.

4. An image forming apparatus according to claim 1 , wherein the control device performs control to form an image pattern of only one color among the plurality of colors, on the first page interval.

5. An image forming apparatus according to claim 1 , wherein the control device performs control to correct a timing when the exposure unit emits a laser beam for correcting misregistration.

6. An image forming apparatus according to claim 1 , wherein the control device performs control to correct a timing when the exposure unit emits a laser beam for correcting misregistration.

7. An image forming apparatus, comprising:
a plurality of image forming devices, each including a developing device that develops an electrostatic latent image formed on an image bearing member to form a toner image, and a transferring device that transfers the toner image developed by the developing device on an intermediate transfer member or a transfer material conveyed by a transfer material conveyance member, for each of a plurality of colors;
an exposure unit that irradiates the image bearing members with a laser beam to form the electrostatic latent image on the image bearing members;
a detector that detects an image pattern for correcting misregistration of each color, the image pattern formed on a page between a first image and a second image formed subsequently to the first image on the intermediate transfer member or the conveyed transfer material; and
a control device that corrects the misregistration of each color based on a detection result by the detector,
wherein the control device performs control to form a reference pattern of a plurality of colors for obtaining a reference period for calculating an amount of the misregistration before the first image is formed, obtains the reference period for calculating the amount of the misregistration by comparing a timing based on a detection result of the reference pattern to a timing based on a detection result of the image pattern for each of the plurality of colors, and corrects the misregistration based on the reference period.

Assignees

• Canon Kk

Inventors

• Itoh Masatoshi

Classifications

• G03G15/0189 Primary

  primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence) · CPC title

• G03G15/5058

  using a test patch · CPC title

• G03G2215/0158

  Colour registration · CPC title

• G03G15/01 Primary

  for producing multicoloured copies · CPC title