IMAGE FORMING APPARATUS HAVING TENSION-PROVIDING MECHANISM FOR BELT

Abstract

To enable not only releasing pressurization by a pressurization mechanism for pressurizing a belt thereby preventing a deformation therein but also easily and securely releasing the pressurization mechanism held in the pressure release state, thereby facilitating the installation operation of an apparatus. A pressurization mechanism for pressurizing a belt is in a released state prior to the use of the main body of the apparatus. Prior to the initial use of the main body, the pressurization of the pressurizing mechanism for the belt is exerted in linkage with a user operation of placing a recording material in a feed tray 21.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating an image forming apparatus in an exemplary embodiment 1 of the present invention.

FIG. 2 is a schematic perspective view illustrating a structure for pressure release and hold release in a pressurization mechanism of the exemplary embodiment 1 of the present invention.

FIG. 3 is a partial view illustrating a structure for pressure release and hold release in a pressurization mechanism of the exemplary embodiment 1 of the present invention.

FIGS. 4A, 4B and 4C are views illustrating functions for a tension releasing operation for a belt, in an exemplary embodiment of the present invention.

FIGS. 5A, 5B, 5C and 5D are views illustrating operations of pressure release and hold release in the pressurization mechanism of the exemplary embodiment 1 of the present invention.

FIGS. 6A, 6B and 6C are views illustrating operations of pressure release and hold release in a pressurization mechanism of an exemplary embodiment 2 of the present invention.

FIGS. 7A and 7B are views illustrating a structure for pressure release and hold release in a pressurization mechanism of an exemplary embodiment 2 of the present invention.

FIGS. 8A, 8B and 8C are views illustrating operations of pressure release and hold release in a pressurization mechanism of an exemplary embodiment 3 of the present invention.

FIGS. 9A and 9B are views illustrating operations of pressure release and hold release in a pressurization mechanism of an exemplary embodiment 4 of the present invention.

FIGS. 10A and 10B are schematic perspective views illustrating pressure release and hold release in a background art.

Claims

1. An image forming apparatus comprising: a unit that can be positioned at a first position and a second position with respect to a main body of the apparatus;a belt;a support member in contact with an internal surface of said belt;a tension member which moves said support member which gives said belt a tension; anda restriction member for restricting a movement of said support member;wherein said support member is released from the restriction of said restriction member when said unit is moved from the first position to the second position, and said support member is maintained on release from the restriction of said restriction member even if said unit is moved from the second position to the first position.

2. An image forming apparatus according to claim 1, wherein an image is able to be formed after said unit is returned from the second position to the first position once.

3. An image forming apparatus according to claim 1, wherein said belt is slack, when said restriction member restricts the movement of said support member.

4. An image forming apparatus according to claim 1, wherein said unit is stored in the main body in the first position, and is extracted from the main body in the second position.

5. An image forming apparatus according to claim 4, wherein said unit is a cassette for containing a recording material.

6. An image forming apparatus according to claim 1, further comprising: an image bearing member for bearing a toner image;wherein said belt contributes in transferring the toner image from said image bearing member, onto a recording material.

7. An image forming apparatus comprising: a unit that can be positioned at a first position and a second position with respect to a main body of the apparatus;a belt;a support member in contact with an internal surface of said belt;a tension member which moves said support member which gives said belt a tension; anda restriction member for restricting a movement of said support member;wherein an operation which is moving said unit from the first position to the second position and then returning said unit to the first position causes said support member to be released from the restriction of said restriction member, and an image is able to be formed after said operation is done once.

8. An image forming apparatus according to claim 7, wherein an image is able to be formed after said operation is done once.

9. An image forming apparatus according to claim 7, wherein, said support member is maintained on release from the restriction of said restriction member even if said unit is moved from the second position to the first position.

10. An image forming apparatus according to claim 7, wherein said belt is slack, when restriction member restricts the movement of said support member.

11. An image forming apparatus according to claim 7, wherein said unit is stored in the main body in the first position, and is extracted from the main body in the second position.

12. An image forming apparatus according to claim 7, further comprising: an image bearing member for bearing a toner image;wherein said belt contributes in transferring the toner image from said image bearing member, onto a recording material.

13. An image forming apparatus comprising: a sheet feed unit extractable from a main body of the apparatus;a belt;a tension member for providing said belt with a tension; anda tension-providing mechanism which, by an operation which is extracting said sheet feed unit from the main body of the apparatus and then storing it into the main body of the apparatus, causes said tension member to provide said belt with a tension.