Image forming apparatus

Patent metadata

Field	Value
Publication number	US-2016147175-A1
Application number	US-201615011316-A
Country	US
Kind code	A1
Filing date	Jan 29, 2016
Priority date	Jul 31, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

To accomplish precise correction of the position of the toner image formed by the image forming station, in the device using the two-component developer.
An electrostatic latent image for forming a color misregistration correction pattern 9 for color misregistration correcting includes a first latent image pattern 301 and a second latent image pattern 302 at the position downstream of the first latent image pattern 301 with respect to the moving direction of the electrostatic latent image. The toner image resulting from the development of the first latent image pattern has a width, measured in the image moving direction, which is larger than that of the toner image resulting from the development of a latent image pattern alone which is the same as the first latent image pattern, or the toner image resulting from the development of the first latent image pattern has an image density in downstream end portion with respect to the moving direction, which density is higher than that of the toner image resulting from the development of the latent image pattern alone which is the same as the first latent image pattern.

First claim

1 . An image forming apparatus comprising:
a plurality of image forming stations configured to form respective toner images; said image forming station each including a rotatable image bearing member, a latent image forming device configured to form an electrostatic latent image on said image bearing member, and a developing device configured to develop the electrostatic latent image formed on said image bearing member, said developing device including a developer carrying member configured to carry a developer comprising toner and a carrier and movable in the same direction at a position where said developer carrying member is opposed to said image bearing member; a toner sensor configured to detect a toner image for registration correction of images formed by said image forming stations: a controller capable of executing a operation in a mode for correcting a writing position of the images formed by said image forming stations on the basis of a result of detection of the toner images for the registration correction by said toner sensor, wherein in the operation in the mode, said controller effects the control such that in forming a first latent image pattern which is a latent image for the toner image for the registration correction, a second latent image pattern is formed at least in an upstream side of the first latent image pattern except for the downstream side thereof with respect to a moving direction of the image, and said controller controls a formation position of the second latent image pattern such that the toner image resulting from the development of the first latent image pattern has a width, measured in the image moving direction, which is larger than that of the toner image resulting from the development of a latent image pattern alone which is the same as the first latent image pattern, or the toner image resulting from the development of the first latent image pattern has an image density in downstream end portion with respect to the moving direction, which density is higher than that of the toner image resulting from the development of the latent image pattern alone which is the same as the first latent image pattern.

2 . An apparatus according to claim 1 , wherein said controller controls a formation position of the second latent image pattern such that a difference between the width, measured in the image moving direction, of the toner image resulting from the development of the first latent image pattern and a width of the first latent image pattern is not more than 200 μm.

3 . An apparatus according to claim 1 , wherein the first latent image pattern and the second latent image pattern are spaced from each other.

4 . An apparatus according to claim 1 , wherein the second latent image pattern is continuous with the first latent image pattern and has a toner image density which is lower than that of the toner image resulting from the development of the first latent image pattern.

5 . An apparatus according to claim 4 , wherein said developer carrying member carries the developer so that the developer contacts said image bearing member, and wherein a length DA of the second latent image pattern measured in the moving direction, a length d, measured in a rotational moving direction of said image bearing member, of a range in a downstream of a closest portion between said image bearing member and said developer carrying member in which the developer carried on the developer carrying member is in contact with said image bearing member, a peripheral movement speed Vdr of said image bearing member, a peripheral movement speed Vslv of said developer carrying member, a latent image potential of the second latent image pattern, and latent image potential of the first latent image pattern satisfy,
DA>d ×{( Vslv−Vdr )/ Vslv }×{( Tv−Av )/ Tv}.

6 . An apparatus according to claim 1 , wherein said developer carrying member carries the developer so that the developer contacts said image bearing member.

7 . An apparatus according to claim 1 , wherein the density of the toner image resulting from the development of the second latent image pattern is lower than that of the toner image resulting from the development of said first latent image pattern, wherein said controller binarizes an output of said toner sensor from the first toner image resulting from the development of the first latent image pattern and a output of said toner sensor from the second toner image resulting from the development of the second latent image pattern on the basis of a threshold which is between these outputs, and determines a center position the toner image of the range in the first toner image side output of the threshold, and wherein said controller corrects the positions of the toner images formed by said image forming stations on the basis of the determined center position.

8 . An apparatus according to claim 7 , wherein a latent image potential of the second latent image pattern is lower than that of the first latent image pattern.

9 . An image forming apparatus comprising:
a plurality of image forming stations configured to form respective toner images; said image forming station each including a rotatable image bearing member, a latent image forming device configured to form an electrostatic latent image on said image bearing member, and a developing device configured to develop the electrostatic latent image formed on said image bearing member, said developing device including a developer carrying member configured to carry a developer comprising toner and a carrier and movable in the same direction at a position where said developer carrying member is opposed to said image bearing member; a toner sensor configured to detect a toner image for registration correction of images formed by said image forming stations: a controller capable of executing a operation in a mode for correcting a writing position of the images formed by said image forming stations on the basis of a result of detection of the toner images for the registration correction by said toner sensor, wherein in the operation in the mode, said controller effects the control such that in forming a first latent image pattern which is a latent image for the toner image for the registration correction, a second latent image pattern is formed in a upstream side of the first latent image pattern with respect to a moving direction of the image, and said controller controls a formation position of the second latent image pattern such that the toner image resulting from the development of the first latent image pattern has a width, measured in the image moving direction, which is larger than that of the toner image resulting from the development of a latent image pattern alone which is the same as the first latent image pattern, or the toner image resulting from the development of the first latent image pattern has an image density in downstream end portion with respect to the moving direction, which density is higher than that of the toner image resulting from the development of the latent image pattern alone which is the same as the first latent image pattern, and wherein said controller controls a formation position of the second latent image pattern such that a difference between the width, measured in the image moving direction, of the toner image resulting from the development of the first latent image pattern and a width of the first latent image pattern is not more than 200 μm.

10 . An apparatus according to claim 9 , wherein the first latent image pattern and the second latent image pattern are spaced from each other.

11 . An apparatus according to claim 9 , wherein the second latent image pattern is continuous with the first latent

Assignees

• Canon Kk

Inventors

• Ohkubo Yuji
• Noguchi Akihiro

Classifications

• G03G15/0824 Primary

  Physics · mapped topic

• G03G2215/0161

  Generation of registration marks · CPC title

• G03G15/0189 Primary

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

• G03G15/5058

  using a test patch · CPC title

• G03G15/0849 Primary

  Detection or control means for the developer concentration · CPC title