Image forming apparatus

Patent metadata

Field	Value
Publication number	US-10545425-B2
Application number	US-201815935189-A
Country	US
Kind code	B2
Filing date	Mar 26, 2018
Priority date	Apr 10, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

An image forming apparatus includes a photosensitive member, a charging roller, an exposure device, a developing device, a transfer member, a fixing device, a voltage source for output the charging voltage, an executing portion for forming a test chart including a plurality of adjusting images in setting of peak-to-peak voltage values of AC voltages at a plurality of different values, a first inputting portion through which an instruction of execution of forming the test chart is inputted, and a second inputting portion through which an instruction of setting a value of peak-to-peak voltage values of the AC voltage during image formation is inputted.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a rotatable photosensitive member;
a charging roller configured to electrically charge said photosensitive member by applying a charging voltage in a form of a DC voltage biased with an AC voltage;
an exposure device configured to expose said photosensitive member charged by said charging roller to light to form an electrostatic latent image;
a developing device configured to develop the electrostatic latent image into a toner image by depositing toner on the electrostatic latent image formed on said photosensitive member;
a transfer member configured to transfer the toner image onto a recording material;
a fixing device configured to fix the transferred toner image on the recording material;
a voltage source configured to output the charging voltage applied to said charging roller;
an executing portion configured to form a test chart including a plurality of adjusting images on the recording material, the plurality of adjusting images being formed by said photosensitive member charged by applying charging voltages in the form of a predetermined DC voltage biased with AC voltages of different peak-to-peak voltage values, respectively;
a first inputting portion through which an instruction of execution of forming the test chart is inputted; and
a second inputting portion through which an instruction of setting a value of the peak-to-peak voltage values of the AC voltage during image formation is inputted.

2. An image forming apparatus according to claim 1 , comprising a plurality of image forming stations each including said photosensitive member, said charging roller, said exposure device and said developing device,
wherein said executing portion is configured to form the test chart so that the adjusting images correspond to said image forming stations, respectively.

3. An image forming apparatus according to claim 2 , wherein said developing devices corresponding to said image forming stations, respectively, use toners different in color.

4. An image forming apparatus according to claim 3 , wherein the adjusting images include a plurality of multi-order color adjusting images obtained by superposing an image of yellow toner of the toners different in color with a respective toner of the toners of colors different from yellow.

5. An image forming apparatus according to claim 4 , wherein when the multi-order color adjusting images are formed, said executing portion is configured to control the charging voltage so that the peak-to-peak voltage corresponding to said image forming station using the yellow toner is set so as to be successively changed to a plurality of different values and so that the peak-to-peak voltage corresponding to said image forming station using the toner of the color different from yellow is set at a predetermined value common to that of the multi-order color adjusting images.

6. An image forming apparatus according to claim 1 , wherein said executing portion changes the peak-to-peak voltages of the AC voltages corresponding to the adjusting images, respectively, in an ascending order.

7. An image forming apparatus according to claim 1 , wherein said executing portion is configured to form the test chart so that with respect to a direction substantially perpendicular to a recording material feeding direction, a length of a region including the adjusting images of the test chart is substantially equal to a length of a maximum image forming region.

8. An image forming apparatus according to claim 1 , wherein said executing portion is configured to form the test chart so that all of the adjusting images are formed on a single recording material.

9. An image forming apparatus according to claim 1 , wherein said executing portion displays information associated with each of the adjusting images at a position corresponding to each of the adjusting images.

10. An image forming apparatus according to claim 9 , wherein said first inputting portion is constituted so that an operator is capable of inputting the information corresponding to at least one adjusting image selected from the adjusting images included in the test chart to be outputted.

11. An image forming apparatus according to claim 10 , wherein said executing portion is configured to set the peak-to-peak voltage of the charging voltage applied to said charging roller in an image forming period at the peak-to-peak voltage corresponding to the information inputted through said second inputting portion.

12. An image forming apparatus according to claim 1 , wherein for the test chart, of recording materials on which an image can be formed by said image forming apparatus, the recording material having a maximum length with respect to a direction substantially perpendicular to a recording material feeding direction is used.

13. An image forming apparatus according to claim 1 , wherein for the test chart, of recording materials on which an image can be formed by said image forming apparatus, the recording material having a maximum length with respect to a recording material feeding direction is used.

14. An image forming apparatus according to claim 1 , further comprising a setting portion configured to set the peak-to-peak voltage value, providing a predetermined target discharge current value, in a period other than an image forming period, on the basis of a detection result of values of alternating currents flowing through said charging roller when said photosensitive member is charged by applying, to said charging roller, the charging voltages successively changed to the different peak-to-peak voltage values while maintaining the predetermined DC voltage,
wherein said executing portion is configured to form the test chart so that the peak-to-peak voltage value when at least one of the adjusting images is formed is set at the peak-to-peak voltage value providing the predetermined target discharge current value set by said setting portion.

15. An image forming apparatus according to claim 1 , further comprising an environment sensor configured to detect at least one of a temperature and a humidity at an inside or an outside of said image forming apparatus,
wherein said executing portion is configured to control on the basis of a detection result of said environment sensor so as to change the peak-to-peak voltage value when the adjusting images are formed.

16. An image forming apparatus according to claim 1 , wherein said executing portion is configured to control on the basis of an amount of use of at least one of said photosensitive member and said charging roller so as to change the peak-to-peak voltage value when the adjusting images are formed.

17. An image forming apparatus according to claim 1 , wherein the plurality of adjustment images extend in a direction perpendicular to a feeding direction of the recording material.

Assignees

• Canon Kk

Inventors

• Makino Masahiro

Classifications

• G03G15/5004 Primary

  Power supply control, e.g. power-saving mode, automatic power turn-off · CPC title

• G03G15/0152

  onto which the monocolour toner images are superposed before common transfer from the recording member · CPC title

• G03G15/0266

  Arrangements for controlling the amount of charge · CPC title

• G03G15/5016

  User-machine interface; Display panels; Control console · CPC title

• G03G2215/00569

  Calibration, test runs, test prints · CPC title