Transfer belt unit and image forming apparatus having the same

Abstract

A transfer belt unit and an image forming apparatus having the same are provided. The transfer belt unit includes a transfer belt circulating and traveling and transferring a toner image formed on a photosensitive body onto a printable medium. A plurality of support rollers support an inner circumference of the transfer belt. A pair of belt guides respectively attached to both edges of the inner circumference of the transfer belt are engaged with a regulating portion disposed in the support rollers to allow the transfer belt to travel in a substantially straight line and each having a joint portion. The joint portion comprises first and second ends separated from each other to be substantially parallel to each other when inclined with respect to a traveling direction of the transfer belt. The second end is located in a posterior position of the first end with respect to the traveling direction of the transfer belt and an external edge of the second end is chamfered.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

FIG. 1 is an elevational view in partial cross section of a tandem type image forming apparatus according to an exemplary embodiment of the present invention;

FIG. 2 is an elevational view in partial cross section of an intermediate transfer type image forming apparatus according to an exemplary embodiment of the present invention;

FIGS. 3 and 4 are perspective views of a transfer belt unit according to an exemplary embodiment of the present invention; and

FIG. 5 is a plan view of a joint portion of a transfer belt according to an exemplary embodiment of the present invention.

Claims

1. A transfer belt unit, comprising: a transfer belt circulating and traveling and transferring a toner image formed on a photosensitive body onto a printable medium;a plurality of support rollers supporting an inner circumference of the transfer belt; anda pair of belt guides respectively attached to both edges of the inner circumference of the transfer belt and engaging a regulating portion of each support roller to allow the transfer belt to travel in a substantially straight line, each of the belt guides having a joint portion,wherein the joint portion comprises first and second ends separated from each other to be substantially parallel to each other and inclined with respect to a traveling direction of the transfer belt, andthe second end is located rearwardly of the first end with respect to the traveling direction of the transfer belt, and an external edge of the second end is chamfered.

2. The transfer belt unit of claim 1, wherein an external vertex portion of the second end has an inclined acute angle with respect to the traveling direction of the transfer belt.

3. The transfer belt unit of claim 2, wherein each vertex portion disposed on the first and second ends is chamfered in a direction substantially parallel to the traveling direction of the transfer belt.

4. The transfer belt unit of claim 3, wherein the pair of joint portions are formed in different positions along the traveling direction of the transfer belt.

5. The transfer belt unit of claim 1, wherein a separation distance between the first and second ends is approximately between 1.5-2.0 mm.

6. The transfer belt unit of claim 1, wherein an amount of chamfer with respect to an external edge of the second end is less than approximately ½ of a thickness of the belt guide.

7. An electrophotographic image forming apparatus comprising: a photosensitive body;an exposure unit;a developing unit;a fusing unit; anda transfer belt unit,wherein the transfer belt unit comprisesa transfer belt circulating and traveling and transferring a toner image formed on a photosensitive body onto a printable medium;a plurality of support rollers supporting an inner circumference of the transfer belt; anda pair of belt guides respectively attached to both edges of the inner circumference of the transfer belt and engaging a regulating portion of each of the support rollers to allow the transfer belt to travel in a substantially straight line, each of the belt guides having a joint portion,wherein the joint portion comprises first and second ends separated from each other to be substantially parallel to each other and inclined with respect to a traveling direction of the transfer belt, andthe second end is located rearwardly of the first end with respect to the traveling direction of the transfer belt, and an external edge of the second end is chamfered.

8. The electrophotographic image forming apparatus of claim 7, wherein an external vertex portion of the second end has an inclined acute angle with respect to the traveling direction of the transfer belt.

9. The electrophotographic image forming apparatus of claim 8, wherein each vertex portion disposed on the first and second ends is chamfered in a direction substantially parallel to the traveling direction of the transfer belt.

10. The electrophotographic image forming apparatus of claim 9, wherein the pair of joint portions are formed in different positions along the traveling direction of the transfer belt.

11. The electrophotographic image forming apparatus of claim 7, wherein a separation distance between the first and second ends is between approximately 1.5-2.0 mm.

12. The electrophotographic image forming apparatus of claim 7, wherein an amount of chamfer with respect to an external edge of the second end is less than approximately ½ of a thickness of the belt guide.

13. A transfer belt unit, comprising: a transfer belt to transfer a toner image formed on a photosensitive body onto a printable medium;a plurality of support rollers supporting an inner surface of the transfer belt and around which the transfer belt travels;first and second belt guides respectively attached to first and second edges of the inner surface of the transfer belt, the first and second belt guides engaging a regulating portion of each of the plurality of support rollers such that the transfer belt travels in a substantially straight line; andeach of the belt guides having a joint portion, the joint portion comprising first and second ends separated from each other and inclined with respect to a traveling direction of the transfer belt.

14. The transfer belt unit of claim 13, wherein the first and second ends of each of the first and second belt guides are substantially parallel.

15. The transfer belt unit of claim 14, wherein the second end is located rearwardly of the first end with respect to the traveling direction of the transfer belt.

16. The transfer belt unit of claim 15, wherein an external edge of the second end is chamfered.

17. The transfer belt unit of claim 13, wherein an external vertex portion of the first and second ends of each belt guide has an inclined acute angle with respect to the traveling direction of the transfer belt.

18. The transfer belt unit of claim 17, wherein each vertex portion is chamfered in a direction substantially parallel to the traveling direction of the transfer belt.

19. The transfer belt unit of claim 13, wherein a separation distance between the first and second ends is approximately between 1.5-2.0 mm.

20. The transfer belt unit of claim 13, wherein an amount of chamfer with respect to an external edge of the second end is less than approximately ½ of a thickness of the belt guide.