Image forming apparatus

Patent metadata

Field	Value
Publication number	US-2016170357-A1
Application number	US-201514953639-A
Country	US
Kind code	A1
Filing date	Nov 30, 2015
Priority date	Dec 12, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

An image forming apparatus includes: an image bearing member, a developing device, and a controller configured to execute an operation in a forced consumption mode. The controller includes a difference calculating portion, an integrating portion, and a flag. In a case where the flag is set when a predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller executes the operation in the forced consumption mode, and in a case where the flag is reset when the predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller continues an image forming operation without executing the operation in the forced consumption mode.

First claim

What is claimed is:

1 . An image forming apparatus comprising:
an image bearing member; a developing device configured to develop an electrostatic latent image, formed on said image bearing member, with a toner; and a controller configured to execute an operation in a forced consumption mode during a continuous image forming job for forming images on a plurality of recording materials continuously, and in the operation in the forced consumption mode, the toner is forcedly consumed by said developing device in a region of said image bearing member corresponding to a non-image forming region between a recording material and a subsequent recording material, wherein said controller includes, a difference calculating portion configured to calculate a difference between a consumption value depending on an amount of the toner consumed every predetermined unit of image formation and a reference value set for the predetermined unit, an integrating portion configured to integrate the difference to obtain an integral value, and a flag set when the integrated value is larger than a predetermined threshold and reset when the integrated value is smaller than the predetermined threshold, wherein in a case where the integrated value exceeds the predetermined threshold during the continuous image forming job, said controller permits the image formation on a predetermined number on the recording materials from a time when the integrated value exceeds the predetermined threshold, and wherein in a case where the flag is set when a predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then said controller executes the operation in the forced consumption mode, and in a case where the flag is reset when the predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then said controller continues an image forming operation without executing the operation in the forced consumption mode.

2 . An image forming apparatus according to claim 1 , wherein the predetermined number and the predetermined time vary depending on a size of the recording materials subjected to the image formation.

3 . An image forming apparatus according to claim 1 , wherein in a case where the number of the recording materials subjected to the image formation until the image forming job is ended after the integrated value exceeds the predetermined threshold is more than the predetermined number and is not more than a certain number of the recording materials, said controller does not execute the operation in the forced consumption mode until a final image in the image forming job is formed but executes the operation in the forced consumption mode after the final image in the image forming job is formed.

4 . An image forming apparatus according to claim 1 , wherein said controller causes said developing device to consume the toner in an amount corresponding to the predetermined threshold in the operation in this forced consumption mode.

5 . An image forming apparatus according to claim 1 , wherein said controller determines an amount of the toner consumed in the operation in the forced consumption mode depending on an integrated value integrated by said integrating portion after the integrated value exceeds the predetermined threshold.

6 . An image forming apparatus according to claim 1 , wherein said difference calculating portion calculates the difference by subtracting the consumption value from the reference value, and
wherein when a value obtained by integrating the difference by said integrating portion is a negative value, said controller resets the integrated value of the integrating portion to zero.

Assignees

• Canon Kk

Inventors

• Saito Fumiyoshi
• Nose Katsuya
• Yago Toshihisa
• Mugita Naoki

Classifications

• G03G15/556 Primary

  for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement · CPC title

• G03G2215/0607

  two-component · CPC title

• G03G15/09

  using magnetic brush · CPC title

• G03G15/0849

  Detection or control means for the developer concentration · CPC title

• G03G15/0844 Primary

  Arrangements for purging used developer from the developing unit · CPC title