US 2008/0304853 A1 · Image forming apparatus

Abstract

An aspect of the invention provides a charging control device of a color image forming apparatus, and the charging control device can properly control a charging potential of an image bearing body such that fog and uneven density are not generated even in a low-temperature environment. The image forming apparatus includes a high-voltage generation circuit 91 which applies an oscillating voltage to the charging member 42 disposed in contact with an image bearing body 41, a direct-current voltage and an alternating-current voltage being superimposed to form the oscillating voltage; a current detection unit 92 which detects a direct current value passed from the charging member 42 to the image bearing body 41; and a voltage control unit 96 which controls the alternating-current voltage such that the detected direct-current value is maintained in a target current range. The image forming apparatus also includes an aging control unit 95 to perform running-in. The aging control unit 95 rotates and drives the image bearing body 41 while retaining the alternating-current voltage and the direct-current voltage at previously-set predetermined voltages.

Claims12

Dependent claims

An image forming apparatus including a charging member which is disposed while brought into contact with or close to an image bearing body,

the image forming apparatus comprising:
a high-voltage generation circuit which applies an oscillating voltage to the charging member, a direct-current voltage and an alternating-current voltage being superimposed to form the oscillating voltage;
a current detection unit which detects a direct current value passed from the charging member to the image bearing body;
a voltage control unit which controls a peak-to-peak voltage value of the alternating-current voltage applied from the high-voltage generation circuit to the charging member such that the direct current value detected by the current detection unit falls within a target current range;
and
an aging control unit which rotates and drives the image bearing body while retaining the alternating-current voltage and the direct-current voltage at previously-set predetermined voltages.

3 more elements

A tandem-type color image forming apparatus including a charging member which is disposed while brought into contact with or close to each of a plurality of image bearing bodies sequentially arranged along a sheet conveyance direction,

the tandem-type color image forming apparatus comprising:
a high-voltage generation circuit which separately applies an oscillating voltage to each charging member, a direct-current voltage and an alternating-current voltage being superimposed to form the oscillating voltage;
a current detection unit which can detect a direct current value passed from each charging member to each image bearing body;
a voltage control unit which separately controls a peak-to-peak voltage value of the alternating-current voltage applied from the high-voltage generation circuit to each charging member such that the direct current value detected by the current detection unit falls within a target current range;
and
an aging control unit which rotates and drives the image bearing body while retaining the alternating-current voltage and the direct-current voltage at previously-set predetermined voltages.

3 more elements

Dependencies are inferred from the claim text.

Image forming apparatus

Life of this patent

Image forming apparatus

Life of this patent

Abstract

Claims12