IMAGE FORMING APPARATUS

• US 20150234321A1
• Filed: 02/13/2015
• Published: 08/20/2015
• Est. Priority Date: 02/19/2014
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Suzuki, Hideaki
• Granted Patent: US 9,389,536 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G03G 15/0822 Arrangements for preparing, mixing, supplying or dispensing developer
• CPC Class Codes: G03G 15/0848 Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
• CPC Class Codes: G03G 15/0865 Arrangements for supplying new developer
• CPC Class Codes: G03G 15/0868 Toner cartridges fulfilling a continuous function within the electrographic apparatus during the use of the supplied developer material, e.g. toner discharge on demand, storing residual toner, acting as an active closure for the developer replenishing opening
• CPC Class Codes: G03G 15/0877 Arrangements for metering and dispensing developer from a developer cartridge into the development unit
• CPC Class Codes: G03G 15/0889 for agitation or stirring
• CPC Class Codes: G03G 15/5054 by measuring the characteristics of an intermediate image carrying member or the characteristics of an image on an intermediate image carrying member, e.g. intermediate transfer belt or drum, conveyor belt

Abstract

A control portion of this image forming apparatus can selectively execute first and second modes. The first mode is a mode of forming a controlling toner image in an inter-image period until when a succeeding electrostatic latent image is developed after when a preceding electrostatic latent image is developed. The second mode is executed with priority over the first mode in a case when the integrated value of the values related to the toner replenishing amount is greater than a predetermined threshold value.

Claims

1. An image forming apparatus comprising:

an image carrier;

a developing apparatus including;

a developer container configured to store developer containing toner and carrier;

an agitating member rotating and agitating the developer within the developer container, the developing apparatus developing an electrostatic latent image formed on the image carrier by the toner at a developing position and forming a toner image;

a developer replenishing apparatus configured to replenish the developer to the developer container corresponding to a toner consumption amount;

a control portion capable of selectively executing first and second modes,

the first mode being a mode of forming a controlling toner image between a succeeding image and a preceding image in a case when a number of image forming sheets is more than a predetermined threshold number during a consecutive image forming job in which images are formed consecutively on recording media, and the second mode being a mode of driving the agitating member such that a total number of rotations of the agitating member in a period until when the succeeding image reaches the developing position after when the preceding image passes the developing position is greater than a total number of rotations of the agitating member in the first mode in a case when the integrated value of the values related to the toner replenishing amount is greater than the predetermined threshold value during the consecutive image forming job in which the images are formed consecutively on the recording media; and

a resetting portion resetting the integrated value in a case when the second mode is executed.

2. The image forming apparatus according to claim 1, wherein the control portion increases a time for driving the agitating member in the second mode more than that in the first mode.

3. The image forming apparatus according to claim 1, wherein the control portion adopts a video counter value of an image to be formed as the value related to the toner replenishing amount.

4. The image forming apparatus according to claim 1, wherein the control portion forms the controlling toner image in the second mode.

5. The image forming apparatus according to claim 1, wherein the control portion calculates a cumulative number of recording media on which images have been formed and executes the first mode without executing the second mode in the inter-image period in a case when the values related to the toner replenishing amount is less than the predetermined threshold value and the cumulative number of recording media is greater than a predetermined threshold value.

6. The image forming apparatus according to claim 1, wherein the control portion quickens driving speed of the agitating member in the second mode to be faster than that of the first mode.

7. The image forming apparatus according to claim 1, wherein the developer replenishing apparatus includes a toner container storing toner and a replenishing member configured to rotate to replenish the toner from the toner container to the developer container, and

wherein the control portion adopts a number of rotations of the replenishing member as the value related to the toner replenishing amount.

8. The image forming apparatus according to claim 1, wherein the developing apparatus includes:

a developer carrier configured to carry the developer agitated by the agitating member, to transfer the toner of the developer to the image carrier and to develop the electrostatic latent image formed on the image carrier; and

a driving source driving the developer carrier and the agitating member; and

wherein the control portion controls the number of rotations of the agitating member by controlling the driving source.

9. The image forming apparatus according to claim 2, wherein the control portion calculates an average image ratio which is an image ratio per sheet of a predetermined number of image forming sheets and the larger the average image ratio, the more the control portion delays starting of formation of the succeeding electrostatic latent image.