IMAGE FORMING APPARATUS

• US 20190018355A1
• Filed: 07/09/2018
• Published: 01/17/2019
• Est. Priority Date: 07/13/2017
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kudo, Yoshiki, Shimomura, Masaki, Uchiyama, Akihiko
• Granted Patent: US 10,642,209 B2
• Time in Patent Office: Days
• CPC Class Codes: G03G 15/01 for producing multicoloured copies colour correction in photography G03C; colour correction in printing plate production
• CPC Class Codes: G03G 15/0131 for transferring a pattern to a second base
• CPC Class Codes: G03G 15/5058 using a test patch
• CPC Class Codes: G03G 15/556 for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement
• CPC Class Codes: G03G 2215/00042 Optical detection
• CPC Class Codes: G03G 2215/00059 on intermediate image carrying member, e.g. transfer belt
• CPC Class Codes: G03G 2215/00063 Colour

Abstract

An image forming apparatus including: a developing roller configured to develop an electrostatic latent image on a photosensitive drum to form a toner image; a belt onto toner image is transferred; a detection unit configured to detect a density of an image for detection formed on the belt; and a controller configured to perform hue adjustment based on a detection result of the detection unit, wherein the image forming apparatus performs image formation in a second mode using a color gamut different from a color gamut in a first mode, and the controller obtains a lookup table, which indicates a correlation between image data to be used and input image data in the second mode, based on the detection result in the first mode and a correlation of density between the first mode and the second mode.

Claims

1. An image forming apparatus, comprising:

a photosensitive drum;

an exposure unit configured to expose the photosensitive drum to light to form an electrostatic latent image on the photosensitive drum;

a developing roller configured to develop the electrostatic latent image on the photosensitive drum which has been formed by the exposure unit with toner to form a toner image on the photosensitive drum;

a belt, the toner image formed on the photosensitive drum being transferred onto the belt or a recording material carried by the belt;

a detection unit configured to detect a density of an image for detection formed on the belt; and

a controller configured to perform hue adjustment based on a result of detecting the density of the image for detection by the detection unit,

wherein the image forming apparatus is operable so as to perform image formation in a second mode using a color gamut different from a color gamut in a first mode, and

wherein the controller is configured to obtain a lookup table, which indicates a correlation between image data to be used and input image data in the second mode, based on the result of detecting the density of the image for detection by the detection unit in the first mode and a correlation of density between the first mode and the second mode.

2. An image forming apparatus according to claim 1, wherein the controller obtains the lookup table based on the result of detecting the density of the image for detection and a parameter for controlling a supply amount of toner to be supplied from the developing roller to the photosensitive drum.

3. An image forming apparatus according to claim 2, wherein the parameter includes one of a circumferential speed difference, which is a difference between a rotation speed of the developing roller and a rotation speed of the photosensitive drum, and a rotation amount of the developing roller.

4. An image forming apparatus according to claim 1, wherein the controller is configured to obtain image data for a current photosensitive drum and a current developing roller and a density ratio between a density obtained in the first mode and a density obtained in the second mode based on data on the density obtained in each of the first mode and the second mode under a predetermined condition, a current use amount of toner, and a degree of use of the current photosensitive drum, and to obtain the lookup table based on a detection result obtained by the detection unit in the first mode and the density ratio.

5. An image forming apparatus according to claim 4, wherein the data on the density obtained in each of the first mode and the second mode under the predetermined condition includes:

a first density ratio between a density in the first mode and a density in the second mode which have been obtained through use of a new photosensitive drum and a new developing roller;

a second density ratio between a density in the first mode and a density in the second mode which have been obtained through use of the new photosensitive drum and a developing roller subjected to image formation on a predetermined number of recording materials;

a third density ratio between a density in the first mode and a density in the second mode which have been obtained through use of a photosensitive drum exhibiting a large degree of use and the new developing roller; and

a fourth density ratio between a density in the first mode and a density in the second mode which have been obtained through use of the photosensitive drum exhibiting a large degree of use and the developing roller subjected to the image formation on the predetermined number of recording materials.

6. An image forming apparatus according to claim 4, further comprising a cartridge including the photosensitive drum, the developing roller, and a nonvolatile memory,

wherein the nonvolatile memory is configured to store data on the current use amount of the toner and data on the degree of use of the current photosensitive drum.

7. An image forming apparatus according to claim 3, wherein the density becomes higher as the circumferential speed difference becomes larger.

8. An image forming apparatus according to claim 1, wherein the density becomes lower as use of the photosensitive drum progresses.

9. An image forming apparatus according to claim 1, wherein the density becomes higher as use of the developing roller progresses until a predetermined use amount of the developing roller is reached, and the density maintains a constant level after the predetermined use amount is reached.

10. An image forming apparatus according to claim 1, wherein the controller is configured to obtain a lookup table for a low density equal to or lower than a predetermined density based on the lookup table obtained with a density higher than the predetermined density in the second mode.

11. An image forming apparatus according to claim 1, wherein the second mode includes a wide color gamut print mode using a color gamut wider than the color gamut in the first mode.

12. An image forming apparatus according to claim 1, wherein the second mode includes a toner save print mode in which a consumption amount of toner is smaller than a consumption amount of toner in the first mode.