Image forming apparatus

Patent metadata

Field	Value
Publication number	US-12105462-B2
Application number	US-202217985240-A
Country	US
Kind code	B2
Filing date	Nov 11, 2022
Priority date	Nov 18, 2021
Publication date	Oct 1, 2024
Grant date	Oct 1, 2024

Abstract

An image forming apparatus includes a rotatable image bearing member about a rotational axis extending in the axial direction, a charging member, an accommodating portion accommodating toner charged to a predetermined polarity; a developing member, a transfer portion, a static eliminating portion, and a collecting member. In the axial direction, when A is a eliminating width with which the eliminating portion discharges the surface of the image bearing member, B is an effective charging width with which the charging member charges the surface, and C is a collection contacting width with which the collecting member contacts the surface, the formula A<B<C is satisfied. In the axial direction, a surface potential of the surface in an area outside the effective charging width, inside the collection contacting width and in contact with the collecting member is a first potential larger than 0V in the same polarity direction as the predetermined polarity.

First claim

What is claimed is:

1. An image forming apparatus comprising:
a rotatable image bearing member about a rotational axis extending in the axial direction thereof;
a charging member configured to form a charging portion between itself and the image bearing member and to charge a surface of the image bearing member;
an accommodating portion configured to accommodate toner charged to a predetermined polarity;
a developing member configured to form a developing portion between itself and the image bearing member and to form a toner image on the image bearing member by supplying the toner to the image developing portion;
a transfer portion contacting the surface of the image bearing member and configured to transfer the toner image;
an eliminating charge portion configured to eliminate charge on the surface of the image bearing member; and
a collecting member configured to collect a deposited matter deposited on the surface of the image bearing member in contact with the surface of the image bearing member,
wherein with respect to the axial direction, when A is defined as a eliminating charge width with which the eliminating charge portion is capable of eliminating the charge on the surface, B is defined as an effective charging width with which the charging member is capable of charging the surface, and C is defined as a collection contacting width with which the collecting member contacts the surface, the following formula is satisfied:
A<B<C, and

wherein with respect to the axial direction, a surface potential of the surface in an area outside the effective charging width, inside the collection contacting width and in contact with the collecting member is a first potential larger than 0V in the same polarity direction as the predetermined polarity.

2. The image forming apparatus according to claim 1 , wherein a transfer contacting width is defined as a width with which the transfer member contacts the surface with respect to the axial direction,
wherein with respect to the axial direction, a surface potential of the surface in an area outside the transfer contacting width, inside the charging width and in contact with the collecting member is a second potential larger than 0V in the same polarity direction as the predetermined polarity, and
wherein the first potential is smaller than the second potential.

3. The image forming apparatus according to claim 1 , wherein a transfer contacting width is defined as a width with which the transfer member contacts the surface with respect to the axial direction,
wherein with respect to the axial direction, a surface potential of the surface in an area outside the transfer contacting width, inside the charging width and in contact with the collecting member is a second potential larger than 0V in the same polarity direction as the predetermined polarity, and
wherein the first potential is larger than the second potential.

4. The image forming apparatus according to claim 2 , wherein with respect to the axial direction, a surface potential of the surface in an area inside the transfer contacting width and in contact with the collecting member is a third potential, and
wherein the third potential is smaller in absolute value than the second potential.

5. The image forming apparatus according to claim 1 , wherein a transfer contacting width is defined as a width with which the transfer member contacts the surface with respect to the axial direction,
wherein with respect to the axial direction, a surface potential of the surface in an area inside the transfer contacting width and in contact with the collecting member is a third potential, and
wherein the third potential is smaller in absolute value than the first potential.

6. The image forming apparatus according to claim 1 , wherein in the charging portion the charging member charges the surface of the image bearing member to a fourth polarity in the same polarity direction as the predetermined polarity, and wherein the first potential is smaller in absolute value than the fourth potential.

7. The image forming apparatus according to claim 1 , further comprising a voltage applying portion configured to apply a voltage in the same polarity direction as the predetermined polarity to the collecting member.

8. The image forming apparatus according to claim 1 , further comprising a corona charger configured to charge the surface of the image bearing member to the first potential.

9. The image forming apparatus according to claim 1 , wherein the collecting member includes a brush member has conductivity.

10. The image forming apparatus according to claim 1 , wherein the transfer portion transfers the toner imager onto the recording material from the image bearing member.

11. The image forming apparatus according to claim 1 , further comprising a belt onto which the toner image is transferred from the image bearing member by the transfer portion and configured to carry the toner.

12. The image forming apparatus according to claim 1 , wherein the predetermined polarity is a negative polarity.

Assignees

• Canon Kk

Inventors

• Matsushita Shunsuke
• Sato Taichi
• Oshima Nobuo

Classifications

• G03G21/0035

  using a brush; Details of cleaning brushes, e.g. fibre density (G03G21/0064 takes precedence; magnetic brushes G03G21/0047) · CPC title

• G03G21/007

  Arrangement or disposition of parts of the cleaning unit · CPC title

• G03G15/751

  relating to drum (G03G15/757 takes precedence) · CPC title

• G03G2215/025

  using contact charging means having lateral dimensions related to other apparatus means, e.g. photodrum, developing roller · CPC title

• G03G21/1821

  means for connecting the different parts of the process cartridge, e.g. attachment, positioning of parts with each other, pressure/distance regulation (G03G21/1825 takes precedence) · CPC title