US 10,120,323 B2Granted

Image forming apparatus

AssigneeCanon Kabushiki Kaisha

InventorsYusuke Shimizu, Kenichi Iida, Takao Kume, Keisuke Ishizumi, Toshihiko Takayama

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Abstract

The present disclosure is directed to suppressing image defects due to variations in the values of currents flowing through respective photosensitive drums during image formation, and reducing the absolute value of a voltage applied when a primary transfer power supply unit applies a voltage of polarity opposite to that during image formation, to primary transfer members. There is provided an image forming apparatus including a transfer member configured to make contact with an inner peripheral surface of a transfer belt, a first power supply unit configured to apply a voltage to the transfer member, a resistance element connected between the first power supply unit and the transfer member, and a diode connected in parallel with the resistance element in a direction in which a current flowing in a first direction is blocked and a current flowing in a second direction is passed.

Claims21

Dependent claims

An image forming apparatus comprising:

an image bearing member configured to bear a toner image;
a transfer belt configured to rotate in contact with the image bearing member;
a transfer member configured to make contact with an inner peripheral surface of the transfer belt, wherein the transfer member is provided to correspond to the image bearing member;
a first power supply unit configured to apply a voltage to the transfer member, wherein if the first power supply unit applies a voltage of a second polarity opposite to a first polarity to the transfer member, a current flows in a first direction through a position in which the image bearing member makes contact with the transfer belt, and if the first power supply unit applies a voltage of the first polarity to the transfer member, a current flows in a second direction opposite to the first direction through the position in which the image bearing member makes contact with the transfer belt, the first polarity being a normal charging polarity of toner;
a resistance element connected between the first power supply unit and the transfer member;
and
a diode connected in parallel with the resistance element in a direction in which the current flowing in the first direction is blocked and the current flowing in the second direction is passed.

4 more elements

An image forming apparatus comprising:

an image bearing member configured to bear a toner image;
an intermediate transfer belt configured to rotate in contact with the image bearing member, wherein a toner image is primarily transferred from the image bearing member to the intermediate transfer belt in a primary transfer portion in which the image bearing member makes contact with the intermediate transfer belt;
a primary transfer member configured to make contact with an inner peripheral surface of the intermediate transfer belt, wherein the primary transfer member is provided to correspond to the image bearing member;
a secondary transfer member configured to make contact with an outer peripheral surface of the intermediate transfer belt to form a secondary transfer portion, and secondarily transfer the toner image from the intermediate transfer belt to a transfer material;
a counter member opposed to the secondary transfer member via the intermediate transfer belt, wherein the counter member and the primary transfer member are electrically connected;
a power supply unit configured to apply a voltage to the secondary transfer member, wherein if the power supply unit applies a voltage of a second polarity opposite to a first polarity to the secondary transfer member, a current flows through a primary transfer portion via the counter member and the primary transfer member in a first direction, and if the power supply unit applies a voltage of the first polarity to the secondary transfer member, a current flows through the primary transfer portion via the counter member and the primary transfer member in a second direction opposite to the first direction, the first polarity being a normal charging polarity of toner;
a resistance element connected between the power supply unit and the primary transfer member;
and
a first diode connected in parallel with the resistance element in a direction in which the current flowing in the first direction is blocked and the current flowing in the second direction is passed.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/660,794Filed 26 Jul 2017
Priority: JP 2016-15041929 Jul 2016
Published: US 2018/0032023 A11 Feb 2018
Granted: 6 Nov 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G03G 15/80
Apparatus for electrographic processes using a charge pattern: details relating to power supplies, circuits boards, electrical connections
G03G 15/1675
At least one of the recording member or the transfer member being rotatable during the transfer: with means for controlling the bias applied in…
G03G 15/5004
Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode…:…
G03G 15/5008
Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode…:…

Family

US 2018/0032023 A1Pre-grant publication · published 1 Feb 2018
US 10,120,323 B2This patent

From the US filing history. Foreign family members aren’t listed.

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