Image forming apparatus

• US 7,016,619 B2
• Filed: 11/08/2004
• Issued: 03/21/2006
• Est. Priority Date: 07/05/2002
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ito, Mitsuhiro, Sakai, Hiroaki
• Primary Examiner(s): Chen, Sophia S.
• Application Number:
  US10/982,808
• Publication Number:
  US 20050069335A1
• Time in Patent Office: 498 Days
• Field of Search: 399/50, 399/43, 399/45, 399/82, 399/16
• US Class Current: 399/50
• CPC Class Codes: G03G 15/0266 Arrangements for controlling the amount of charge
• CPC Class Codes: G03G 15/55 Self-diagnostics; Malfunction or lifetime display

Abstract

This invention provides an image forming apparatus where the useful life of the image carrier does not become significantly short. This system has a charging unit, a charge voltage loading unit, an exposure unit, a development unit, an image transfer unit and a control unit, wherein, when the transport interval of the plural recording materials is shorter than a predetermined time the AC charge voltage applied to the image carrier during the transport interval being a first AC charge voltage, and when the transport interval is longer than the predetermined time the ac charge voltage applied to the image carrier during the transport interval being a second AC charge voltage, the control unit makes the current running in the charging unit to which the second charge voltage is applied lower than the current running in the charging unit to which the first AC charge voltage is applied.

Claims

1. An image forming apparatus that forms an image in a plurality of print modes differing in a transport interval of recording materials, the image forming apparatus comprising:

charging means for charging an image carrier;

charge voltage loading means for applying a charge voltage to the charging means;

image transfer means for transferring an image formed on the image carrier onto a plurality of recording materials; and

control means for controlling the charge voltage applied by the charge voltage loading means to the charging means,

wherein according to the print modes, during a period in which an image is not formed on the plurality of recording materials, the control means sets a charge voltage which differs from a charge voltage which is set during a period in which an image is formed on the plurality of recording materials.

2. The image forming apparatus according to claim 1, wherein the print modes are modes in which an image is formed on both sides of the plurality of recording materials.

3. The image forming apparatus according to claim 1, wherein the print modes are modes in which the transport intervals are changed according to types of the recording materials.

4. The image forming apparatus according to claim 1, wherein the charge voltage includes an AC charge voltage.

5. The image forming apparatus according to claim 1, wherein the charge voltage is a voltage including a DC charge added to an AC charge voltage.

6. The image forming apparatus according to claim 1, wherein the charge voltage loading means applies a predetermined charge voltage to a non-image formation area of the image carrier.

7. The image forming apparatus according to claim 1, wherein the period in which an image is not formed on the plurality of recording materials is a period in accordance with the transport interval of the plurality of recording materials.

8. An image forming apparatus that forms an image in a plurality of print modes differing in a transport interval of recording materials, the image forming apparatus comprising:

a charging portion configured to charge an image carrier;

a charge voltage loading portion configured to apply a charge voltage to the charging portion;

an image transfer portion configured to transfer an image formed on the image carrier onto a plurality of recording materials; and

a control portion configured to control the charge voltage applied by the charge voltage loading portion to the charging portion,

wherein in accordance with the print modes, during a period in which an image is not formed on the plurality of recording materials, the control portion sets a charge voltage which differs from a charge voltage which is set during a period in which an image is formed on the plurality of recording materials.