Image forming apparatus

Patent metadata

Field	Value
Publication number	US-9052629-B2
Application number	US-201213599921-A
Country	US
Kind code	B2
Filing date	Aug 30, 2012
Priority date	Sep 19, 2011
Publication date	Jun 9, 2015
Grant date	Jun 9, 2015

Abstract

An image forming apparatus forms a color image, and includes an endless intermediate transfer belt which rotates and carries a toner image and plural image forming units for plural colors arranged in tandem along the intermediate transfer belt. Each of the image forming units includes an image carrier which rotates and carries a latent image, a charging device which charges the image carrier, a development device which develops the latent image into a toner image, and a cleaning device which cleans the image carrier after the toner image is transferred to the intermediate transfer belt. The charging device of the extreme upstream image forming unit in the belt direction of rotation is a non-contact charging device not in contact with the image carrier. The extreme downstream image forming unit in the belt direction or rotation includes a lubricant application device which applies a lubricant to the image carrier.

First claim

What is claimed is:

1. An image forming apparatus, comprising:
an endless intermediate transfer belt configured to rotate and carry a toner image thereon; and
a plurality of image forming units for a plurality of colors arranged in tandem along the endless intermediate transfer belt,
each of the plurality of image forming units including:
an image carrier configured to rotate and carry a latent image;
a charging device configured to charge the image carrier to form the latent image;
a development device configured to develop the latent image into a toner image; and
a cleaning device configured to clean the image carrier after the toner image is transferred to the endless intermediate transfer belt, wherein

the charging device is configured as a non-contact charging device not in contact with the image carrier in a farthest upstream one of the plurality of image forming units in the direction of rotation of the endless intermediate transfer belt, and
a farthest downstream one of the plurality of image forming units in the direction of rotation of the endless intermediate transfer belt further includes a lubricant application device configured to apply a lubricant to the image carrier.

2. The image forming apparatus according to claim 1 , further comprising:
a lubricant amount detector configured to detect an amount of lubricant present on the endless intermediate transfer belt; and
a lubricant amount adjustment mechanism configured to adjust an amount of lubricant applied by the lubricant application device in the farthest downstream one of the plurality of image forming units in accordance with the amount of lubricant detected on the endless intermediate transfer belt by the lubricant amount detector.

3. The image forming apparatus according to claim 2 , further comprising:
a belt cleaning blade configured to clean the endless intermediate transfer belt,
wherein the lubricant amount detector detects the amount of lubricant present on the endless intermediate transfer belt by detecting a change in frictional force acting between the intermediate transfer belt and the belt cleaning blade.

4. The image forming apparatus according to claim 2 , wherein
the lubricant application device includes an application member configured to apply the lubricant to the image carrier, and
the lubricant amount adjustment mechanism adjusts a rotation rate of the application member to adjust the amount of lubricant applied by the lubricant application device in the farthest downstream one of the plurality of image forming units.

5. The image forming apparatus according to claim 4 , wherein
the lubricant is a stick-shaped solid lubricant, and
the lubricant amount adjustment mechanism adjusts an amount of indentation of the application member into the stick-shaped solid lubricant to adjust the amount of lubricant applied by the lubricant application device in the farthest downstream one of the plurality of image forming units.

6. The image forming apparatus according to claim 2 , wherein the lubricant amount detector comprises a torque detection device configured to detect changes in drive torque of the intermediate transfer belt.

7. The image forming apparatus according to claim 2 , wherein the lubricant amount detector comprises a deformation amount detection device provided to the belt cleaning blade, the lubricant amount detector being configured to measure changes in elastic deformation of the belt cleaning blade.

8. The image forming apparatus according to claim 7 , wherein the lubricant amount detector is a strain sensor.

9. The image forming apparatus according to claim 1 , wherein the charging device of the farthest downstream one of the plurality of image forming units is a non-contact charging device not in contact with the image carrier.

10. The image forming apparatus according to claim 1 , wherein the farthest downstream one of the plurality of image forming units stores black toner.

11. The image forming apparatus according to claim 1 , wherein the lubricant comprises zinc stearate.

12. The image forming apparatus according to claim 1 , wherein the lubricant comprises zinc stearate and boron nitride.

13. The image forming apparatus according to claim 1 , wherein
the cleaning device provided in each of the plurality of image forming units includes a cleaning blade having an edge layer in contact with the image carrier, and
the edge layer is made of a material having a 100% modulus value ranging from approximately 6 megapascals to approximately 12 megapascals at a temperature of 23 degrees Celsius.

14. The image forming apparatus of claim 1 , wherein only the farthest downstream one of the plurality of image forming units of the plurality of image forming units includes the lubricant application device.

15. The image forming apparatus of claim 1 , wherein the plurality of image forming units, except the farthest downstream one of the plurality of image forming units, do not include any lubricant application devices.

16. An image forming unit, comprising:
an image carrier configured to rotate and carry a latent image;
a charging device configured to charge the image carrier to form the latent image;
a development device configured to develop the latent image into a toner image;
a cleaning device configured to clean the image carrier after the toner image is transferred to an endless intermediate transfer belt of an image forming apparatus; and
a lubricant amount detector configured to detect an amount of lubricant present on the intermediate transfer belt based on a frictional force between the endless intermediate transfer belt and a belt cleaning blade, wherein the image forming unit,
is positioned as a farthest downstream image forming unit in the image forming apparatus, in the direction of rotation of the endless intermediate transfer belt, and
further includes a lubricant application device configured to apply a lubricant to the image carrier.

17. The image forming unit according to claim 16 , wherein the lubricant amount detector comprises a torque detection device configured to detect changes in drive torque of the endless intermediate transfer belt.

18. The image forming unit according to claim 16 , wherein the lubricant amount detector comprises a deformation amount detection device provided to the belt cleaning blade, the deformation amount detection device being configured to measure changes in elastic deformation of the belt cleaning blade.

19. The image forming unit according to claim 18 , wherein the lubricant amount detector is a strain sensor.

20. The image forming unit according to claim 16 , wherein the lubricant comprises zinc stearate and boron nitride.

Assignees

• Watanabe Kazuhiko
• Okamoto Keiji
• Ricoh Co Ltd

Inventors

• Watanabe Kazuhiko
• Okamoto Keiji

Classifications

• G03G21/0094

  fatigue treatment of the photoconductor · CPC title

• G03G2215/0132

  vertical medium transport path at the secondary transfer · CPC title

• G03G21/0011

  using a blade; Details of cleaning blades, e.g. blade shape, layer forming · CPC title

• G03G21/0035

  using a brush; Details of cleaning brushes, e.g. fibre density (G03G21/0064 takes precedence; magnetic brushes G03G21/0047) · CPC title

• G03G21/00

  Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge · CPC title