Image Forming Apparatus Having Casing For Maintaining Relative Positions of Photosensitive Drums

• US 20140086622A1
• Filed: 09/20/2013
• Published: 03/27/2014
• Est. Priority Date: 09/21/2012
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Nakashima, Atsuhisa
• Granted Patent: US 9,367,026 B2
• Time in Patent Office: Days
• US Class Current: 399/107
• CPC Class Codes: G03G 21/1619 Frame structures
• CPC Class Codes: G03G 21/1661 means for handling parts of the apparatus in the apparatus G03G21/1604, G03G21/1642 take precedence

Abstract

An image forming apparatus includes a casing, a plurality of photosensitive drums, and a plurality of developing device. The casing includes a first frame and a second frame. The plurality of photosensitive drums is configured to rotate about an axis line extending in an axial direction and juxtaposed at intervals in the casing. The casing defines one side and the other side in the axial direction. Drive force for rotating the plurality of photosensitive drums is inputted to the one side of the plurality of photosensitive drums. The plurality of developing device is provided to correspond to the plurality of photosensitive drums and configured to supply developing agent to the corresponding photosensitive drum. The first frame is made of metal and is configured to support the one side of each of the plurality of photosensitive drums, and the second frame is made of resin and is configured to support the other side of each of the plurality of photosensitive drums.

Claims

1. An image forming apparatus comprising:

a casing including a first frame and a second frame;

a plurality of photosensitive drums configured to rotate about an axis line extending in an axial direction and juxtaposed at intervals in the casing, the casing defining one side and the other side in the axial direction, drive force for rotating the plurality of photosensitive drums being inputted to the one side of the plurality of photosensitive drums; and

a plurality of developing device provided to correspond to the plurality of photosensitive drums and configured to supply developing agent to the corresponding photosensitive drum,

wherein the first frame is made of metal and is configured to support the one side of each of the plurality of photosensitive drums, and the second frame is made of resin and is configured to support the other side of each, of the plurality of photosensitive drums.

2. The image forming apparatus according to claim 1, wherein the second frame supports an electrode configured to be in electrical connection with the developing device.

3. The image forming apparatus according to claim 1, wherein the casing further includes a third frame made of resin, the third frame being configured to support the first frame,

wherein when projected in the axial direction, a projected surface of the first frame falls within a projected surface of the third frame.

4. The image forming apparatus according to claim 3, further comprising a support plate supporting a drive source configured to generate the drive force and a rotational member configured to transmit the drive force from the drive source to the one side of the plurality of photosensitive drums, the support plate being made of metal, and supported on the third frame.

5. The image forming apparatus according to claim 1, wherein each of the plurality of photosensitive drums is configured to be detachable mounted in the casing,

wherein the first frame is provided with a first support portion configured to support the one side of the plurality of photosensitive drums when the photosensitive drum is mounted,

wherein the second frame is provided with a second support portion configured to support the other side of the plurality of photosensitive drums when the photosensitive drum is mounted.

6. The image forming apparatus according to claim 5, wherein the first support, portion is aligned with the second support portion when projected in the axial direction.

7. The image forming apparatus according to claim 5, wherein the second frame is formed with a second guiding groove for grading the other side of the photosensitive drum when the photosensitive drum is attached to and detached from the casing.

8. The image forming apparatus according to claim 5, wherein the casing further includes a third frame made of resin, the third frame being configured to support the first frame,

wherein when projected in the axial direction, a projected surface of the first frame falls within a projected surface of the third frame.

9. The image forming apparatus according to claim 8, wherein the third frame is formed with a third guiding groove for guiding the one side of the photosensitive drum when the photosensitive drum is attached to and detached from tire casing.

10. The image forming apparatus according to claim 9, wherein the first frame is formed with an opening so as to surround a peripheral edge of the third guiding groove when projected in the axial direction.

11. The image forming apparatus according to claim 9, wherein at least a part of the first support portion falls within the third guide groove when projected in the axial direction.

12. The image forming apparatus according to claim 8, further comprising a support plate supporting a drive source configured to generate the drive force and a rotational member configured to transmit the drive force from the drive source to the one side of the plurality of photosensitive drums, the support plate being supported on the third frame as a separate member.

13. The image forming apparatus according to claim 1, further comprising an exposing unit provided to correspond to the plurality of photosensitive drums and configured to expose the photosensitive drum,

wherein the first frame includes a first exposure positioning member configured to fix a position of the one side of the exposing unit in an arrangement direction, of the plurality of photosensitive drums.

14. The image forming apparatus according to claim 13, wherein the second frame includes a second exposure positioning member configured to fix a position of the other side of the exposing unit in the arrangement direction.

15. The image forming apparatus according to claim 1, further comprising a feeding unit configured to feed a sheet to the photosensitive drum,

wherein the first frame is provided with a first supply positioning part configured to fix a position of the one side of the feeding unit in an arrangement direction of the plurality of photosensitive drum,

wherein the second frame is provided with a second supply positioning part configured to fix a position of the other side of the feeding unit in the arrangement direction.

16. The image forming apparatus according to claim 1, further comprising a fixing unit configured to fix a developing agent image on a sheet,

wherein the first frame is provided with a first fixing unit positioning part configured to fix a position of the one side of the fix unit in an arrangement direction of the plurality of photosensitive drums,

wherein the second frame is provided with a second fixing unit positioning part configured to fix a position of the other side of the fixing unit in the arrangement direction.

17. The image forming apparatus according to claim 1, wherein the casing further includes a fourth frame made of resin and configured to support the second frame,

wherein when projected in the axial direction, a projected surface of the second frame falls within a projected surface of the fourth frame.

18. The image forming apparatus according to claim 17, wherein the second frame has a lower coefficient of thermal expansion than that of the fourth frame.