BELT MEMBER DRIVING MECHANISM, BELT MEMBER DRIVING METHOD AND IMAGE FORMING APPARATUS

Abstract

A belt member driving mechanism includes a first roller having a rotation shaft and configured to be rotated in a first direction, a belt member including a belt surface having a predetermined width in a second direction orthogonal to the first direction and configured to be rotated by a driving force from the first roller, a second roller configured to apply a predetermined tension force to the belt member in cooperation with the first roller, and a temperature control unit, including a detection unit which detects an elongation and/or a contraction of the belt surface of the belt member, configured to produce a temperature difference along the second direction of the belt surface of the belt member to reduce the elongation or contraction.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a diagrammatic view showing one form of an image forming apparatus having a transfer belt member applicable thereto;

FIG. 2 is a diagrammatic view for explaining one form of an oblique movement correction mechanism of the transfer (endless) belt member incorporated into the image forming apparatus shown in FIG. 1;

FIGS. 3A to 3C, each, are a diagrammatic view for explaining the movement of the belt member (the driving by a rotation shaft and oblique movement) shown in FIG. 2;

FIG. 4 is a diagrammatic view for explaining one form of a heating unit of a belt oblique movement correction mechanism shown in FIG. 2;

FIG. 5 is a diagrammatic view for explaining one form of a cooling unit of a belt oblique movement correction mechanism shown in FIG. 2;

FIG. 6 is a diagrammatic block diagram for explaining one form of an oblique movement correction mechanism control section for controlling the belt oblique movement mechanism shown in FIG. 2; and

FIG. 7 is a diagrammatic view for explaining another embodiment of a belt oblique movement correction mechanism (oblique movement correction mechanism incorporated into a rotation shaft as one unit) shown in FIG. 1.

Claims

1. A belt member driving mechanism comprising: a first roller having a rotation shaft and configured to be rotated in a first direction;a belt member including a belt surface having a predetermined width in a second direction orthogonal to the first direction and configured to be rotated by a driving force from the first roller;a second roller configured to apply a predetermined tension force to the belt member in cooperation with the first roller; anda temperature control unit, including a detection unit which detects an elongation and/or a contraction of the belt surface of the belt member, configured to produce a temperature difference along the second direction of the belt surface of the belt member to reduce the elongation or contraction.

2. The driving mechanism according to claim 1, in which the temperature control unit includes a heating source provided on each of at least two places of the belt surface of the belt member along the second direction to allow different portions of the belt surface to be independently heated.

3. The driving mechanism according to claim 1, in which the temperature control unit includes a cooling mechanism provided on each of at least two places of the belt surface of the belt member along the second direction to allow different portions of the belt surface to be independently cooled.

4. The driving mechanism according to claim 1, in which the temperature control unit includes a heating source provided on each of at least two places of the belt surface of the belt member along the second direction to allow the belt surface to be independently heated and a cooling mechanism provided on each of at least of the belt surface of the belt member along the second direction to allow the belt surface to be independently cooled.

5. The drive mechanism according to claim 2, in which the heating source is comprised of a plurality of heater arrays provided in the second direction along the belt surface of the belt member.

6. The drive mechanism according to claim 3, in which the cooling mechanism is comprised of a plurality of cooling member arrays provided at the second direction along the belt surface of the belt member.

7. The drive mechanism according to claim 4, in which the heating source and cooling mechanism are each comprised of a plurality of heater arrays and cooling member arrays provided in the second direction along the belt surface of the belt member.

8. The drive mechanism according to claim 4, in which at least one of the first roller and second roller includes a cylindrical area and the heating source and cooling mechanism are mounted from each open end of the cylindrical area toward an inside as one unit.

9. The drive mechanism according to claim 8, in which the heating source and the cooling mechanism are so provided as to share the inside of the cylindrical area.

10. The driving mechanism according to claim 9, further comprising: a shield structure is so provided in the cylindrical area as to prevent air which is supplied from the cooling mechanism on one open end side from cooling the heating source provided on the other open end side.

11. An image forming apparatus comprising: a first roller having a rotation shaft and configured to be rotated in a first direction;a belt-like photosensitive member including a belt surface having a predetermined width in a second direction orthogonal to the first direction and configured to be rotated by a drive force from the first roller;a second roller configured to apply a predetermined tension force to the belt-like photosensitive member in cooperation with the first roller;an image forming device arranged along a direction in which the belt surface of the belt-like photosensitive member is moved and configured to form any color toner image transferable to a transfer medium conveyed with the movement of the belt surface;a heating mechanism configured to heat a predetermined position on the belt surface of the belt-like photosensitive member;a cooling mechanism configured to cool a predetermined position on the belt surface of the belt-like photosensitive member; anda temperature control unit configured to selectively operate the heating mechanism and cooling mechanism to create a temperature gradient on the belt surface along the second direction.

12. The image forming apparatus according to claim 11, further comprising: a temperature sensor configured to defect temperature at a predetermined position of the belt surface in the second direction so as to be referred to by the temperature control unit; anda displacement sensor configured to detect a positional displacement at the edge of the belt surface so as to be referred to by the temperature control unit.

13. A belt member driving method comprising: detecting displacement of a belt surface of a belt member which is moved by the rotation of a drive roller driven about a rotation shaft;detecting temperature at any position on the belt surface of the belt member; andheating a predetermined position on the belt surface of the belt member, or cooling a predetermined position on the belt surface of the belt member, based on a detected displacement and temperature and controlling an amount of displacement on the belt surface of the belt member in and along a direction of the rotation shaft when the belt surface of the belt member is moved.