Image forming apparatus controlling color reproduction range and tone reproducibility

Patent metadata

Field	Value
Publication number	US-10958808-B2
Application number	US-201916530652-A
Country	US
Kind code	B2
Filing date	Aug 2, 2019
Priority date	Aug 10, 2018
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

An image forming includes a dither processing unit that applies a dither matrix to an image; an exposure unit that exposes a photosensitive drum to form an electrostatic latent image based on the image to which the dither matrix has been applied; a development unit that develops, using a developing material on a developing roller, the formed electrostatic latent image; and a control unit that, based on a print setting change instruction by a user, increases a circumferential speed of the developing roller relative to the circumferential speed of the photosensitive drum and decreases a screen ruling of the dither matrix to be applied by the dither processing unit.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
an exposure unit configured to expose a photosensitive drum to form an electrostatic latent image based on an image to which a dither matrix has been applied;
a development unit configured to develop, using a developing material on a developing roller, the formed electrostatic latent image; and
a controller including a processor and a memory, the controller configured to:
receive a first print setting or a second print setting, wherein the first print setting requests a circumferential speed of the developing roller relative to a circumferential speed of the photosensitive drum that is higher than that which the second print setting requests; and
in a case that the first print setting requesting the higher relative circumferential speed is received, control the developing roller and the photosensitive drum so that the circumferential speed of the developing roller relative to the circumferential speed of the photosensitive drum is higher and set the dither matrix to have a lower screen ruling compared with a case that the second print setting requesting the lower relative circumferential speed is received.

2. The image forming apparatus according to claim 1 , wherein the controller is further configured to, based on a print setting change instruction by a user, control a maximum density to be formed by the exposure unit and the development unit to increase and decrease a screen ruling of the dither matrix.

3. The image forming apparatus according to claim 2 , wherein the maximum density is defined as a density of an image formed onto a sheet when a density value of the image is a maximum value in a range that can be achieved.

4. The image forming apparatus according to claim 3 , wherein the print setting change instruction is a single instruction by the user.

5. An image forming system, comprising:
an exposure unit configured to expose a photosensitive drum to form an electrostatic latent image based on an image to which a dither matrix has been applied;
a development unit configured to develop, using a developing material on a developing roller, the formed electrostatic latent image;
a receiving unit configured to receive a first print setting or a second print setting, wherein the first print setting requests a circumferential speed of the developing roller relative to a circumferential speed of the photosensitive drum that is higher than that which the second print setting requests; and
a controller including a processor and a memory, the controller configured to:
in a case that the first print setting requesting the higher relative circumferential speed is received, control the developing roller and the photosensitive drum so that the circumferential speed of the developing roller relative to the circumferential speed of the photosensitive drum is higher and set the dither matrix to have a lower screen ruling compared with a case that the second print setting requesting the lower relative circumferential speed is received.

6. The image forming system according to claim 5 , wherein the controller is further configured to, based on a print setting change instruction by a user, control a maximum density to be formed by the exposure unit and the development unit to increase and decrease a screen ruling of the dither matrix.

7. The image forming system according to claim 6 , wherein the maximum density is defined as a density of an image formed onto a sheet when a density value of the image is a maximum value in a range that can be achieved.

8. The image forming system according to claim 7 , wherein the print setting change instruction is a single instruction by a user.

Assignees

• Canon Kk

Inventors

• Nagai Jun

Classifications

• H03M1/201

  by dithering · CPC title

• G03G15/0813

  characterised by means in the developing zone having an interaction with the image carrying member, e.g. distance holders · CPC title

• G03G15/36

  Editing, i.e. producing a composite image by copying one or more original images or parts thereof · CPC title

• G03G15/011

  for exposing · CPC title

• G03G15/5008

  Driving control for rotary photosensitive medium, e.g. speed control, stop position control · CPC title