IMAGE FORMING APPARATUS

Abstract

An object of the present invention is to provide an image forming apparatus including a belt-shaped image bearing member; a first transfer member which abuts on the outer peripheral surface of the image bearing member; a second transfer member which abuts on an inner peripheral surface of the image bearing member; transfer electric field forming unit; a bending member which bends the image bearing member from the outer peripheral surface toward the inner peripheral surface on a downstream side of the transfer portion in a traveling direction of the image bearing member; a conductive member in which an electric field is formed with the bending member; and voltage applying unit which applies a voltage having a polarity opposite to the toner to the conductive member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating an image forming portion;

FIG. 2 is an explanatory view of a first embodiment;

FIG. 3 is an explanatory view of a comparative example;

FIG. 4 is an explanatory view of a second embodiment;

FIG. 5 is an explanatory view illustrating an image forming portion of a third embodiment;

FIG. 6 is an explanatory view of the third embodiment; and

FIG. 7 is an explanatory view of a comparative example.

Claims

1. An image forming apparatus comprising: a belt-shaped image bearing member which travels while bearing a toner image including charged toners on an outer peripheral surface thereof;a first transfer member which abuts on the outer peripheral surface of the image bearing member;a second transfer member which abuts on an inner peripheral surface of the image bearing member, the second transfer member, nipping the image bearing member with the first transfer member and forming a transfer portion where the toner image is transferred to a recording material;transfer electric field forming unit which applies a voltage having a polarity opposite to the toner to the first transfer member to form an electric field in the transfer portion, the toner being moved from the image bearing member toward the recording material in the electric field;a bending member which bends the image bearing member from the outer peripheral surface toward the inner peripheral surface on a downstream side of the transfer portion in a traveling direction of the image bearing member;a conductive member which forms an electric field between the bending member and the conductive member; andvoltage applying unit which applies a voltage having a polarity opposite to the toner to the conductive member.

2. An image forming apparatus according to claim 1, comprising cleaning unit which cleans the toner which is remaining on the image bearing member after the toner image is transferred, wherein the bending member is arranged near the transfer portion on an upstream side of the cleaning unit in the traveling direction of the image bearing member.

3. An image forming apparatus according to claim 1, wherein the image bearing member has a volume resistivity ranging from 1×105 Ω·cm to 1×1013 Ω·cm and a surface resistivity ranging from 1×107 Ω/□ to 1×1015 Ω/□.

4. An image forming apparatus according to claim 1, wherein, in the traveling direction of the image bearing member, an electric resistance in an interval between the transfer portion and a region where the bending member abuts on the image bearing member becomes 2000 times or less an electric resistance in a thickness direction of the image bearing member in the transfer portion.

5. An image forming apparatus according to claim 1, wherein the conductive member abuts on a portion of the image bearing member, the portion being abutted by the bending member.

6. An image forming apparatus comprising: a belt-shaped image bearing member which travels while bearing a toner image including charged toners on an outer peripheral surface thereof;a first transfer member which abuts on the outer peripheral surface of the image bearing member;a second transfer member which abuts on an inner peripheral surface of the image bearing member, the second transfer member nipping the image bearing member with the first transfer member and forming a transfer portion where the toner image is transferred to a recording material;transfer electric field forming unit which applies a voltage having the same polarity as the toner to the second transfer member to form an electric field in the transfer portion, the toner being moved from the image bearing member toward the recording material in the electric field;a bending member which bends the image bearing member from the outer peripheral surface toward the inner peripheral surface on a downstream side of the transfer portion in a traveling direction of the image bearing member;a conductive member which forms an electric field between the bending member and the conductive member; andvoltage applying unit which applies a voltage having the same polarity as the toner to the bending member.

7. An image forming apparatus according to claim 6, comprising cleaning unit which cleans the toner which is remaining on the image bearing member after the toner image is transferred, wherein the bending member is arranged near the transfer portion on an upstream side of the cleaning unit in the traveling direction of the image bearing member.

8. An image forming apparatus according to claim 6, wherein the image bearing member has a volume resistivity ranging from 1×105 Ω·cm to 1×1013 Ω·cm and a surface resistivity ranging from 1×107 Ω/□ to 1×1015 Ω/□.

9. An image forming apparatus according to claim 6, wherein, in the traveling direction of the image bearing member, an electric resistance in an interval between the transfer portion and a region where the bending member abuts on the image bearing member becomes 2000 times or less an electric resistance in a thickness direction of the image bearing member in the transfer portion.

10. An image forming apparatus according to claim 6, wherein the conductive member abuts on a portion of the image bearing member, the portion being abutted by the bending member.