Image Forming Apparatus

• US 20100111562A1
• Filed: 10/27/2009
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Original Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Inventors: HASHIMOTO, Junichi, OKABE, Yasushi
• Granted Patent: US 8,577,255 B2
• Time in Patent Office: Days
• US Class Current: 399/112
• CPC Class Codes: G03G 15/0178 using more than one reusable electrographic recording member, e.g. one for every monocolour image
• CPC Class Codes: G03G 15/0194 primary transfer to the final recording medium G03G15/0184 takes precedence
• CPC Class Codes: G03G 15/5008 Driving control for rotary photosensitive medium, e.g. speed control, stop position control
• CPC Class Codes: G03G 15/757 Drive mechanisms for photosensitive medium, e.g. gears
• CPC Class Codes: G03G 21/1647 Mechanical connection means
• CPC Class Codes: G03G 21/1652 Electrical connection means
• CPC Class Codes: G03G 21/1825 Pivotable subunit connection
• CPC Class Codes: G03G 21/1842 for guiding and mounting the process cartridge, positioning, alignment, locks G03G21/1864 and G03G21/1871 take precedence
• CPC Class Codes: G03G 21/1853 the process cartridge being mounted perpendicular to the axis of the photosensitive member
• CPC Class Codes: G03G 21/1867 for electrically connecting the process cartridge to the apparatus, electrical connectors, power supply
• CPC Class Codes: G03G 2221/166 Electrical connectors
• CPC Class Codes: G03G 2221/1684 using extractable subframes, e.g. on rails or hinges
• CPC Class Codes: G03G 2221/1869 Cartridge holders, e.g. intermediate frames for placing cartridge parts therein

Abstract

An image forming apparatus includes a main body, an endless belt, and a drum unit. The drum unit is detachably mounted on the main body. The drum unit is inserted in a mounting direction to mount on the main body. The drum unit has a first end and a second end that is disposed downstream in the mounting direction. The drum unit supports a plurality of photosensitive drums including a black photosensitive drum and color photosensitive drums. The black photosensitive drum has a first axis extending in an axial direction perpendicular to the mounting direction. Each of the color photosensitive drums has a second axis extending in a direction parallel to the axial direction. The black and color photosensitive drums are arranged in the mounting direction. The black photosensitive drum is disposed at a position nearest to the first end. The second end is pivotable about the first axis to be movable between an initial position and a pivot position. The black and color photosensitive drums contact the endless belt when the drum unit is disposed in the initial position. The black photosensitive drum contacts the endless belt and the color photosensitive drums are separated from the endless belt when the drum unit is disposed in the pivot position.

Claims

1. An image forming apparatus comprising:

a main body;

an endless belt; and

a drum unit that is detachably mounted on the main body, the drum unit being inserted in a mounting direction to mount on the main body, the drum unit having a first end and a second end that is disposed downstream in the mounting direction, the drum unit supporting a plurality of photosensitive drums including a black photosensitive drum and color photosensitive drums, the black photosensitive drum having a first axis extending in an axial direction perpendicular to the mounting direction, each of the color photosensitive drums having a second axis extending in a direction parallel to the axial direction, the black and color photosensitive drums being arranged in the mounting direction, the black photosensitive drum being disposed at a position nearest to the first end, the second end being pivotable about the first axis to be movable between an initial position and a pivot position,

wherein the black and color photosensitive drums contact the endless belt when the drum unit is disposed in the initial position, and

wherein the black photosensitive drum contacts the endless belt and the color photosensitive drums are separated from the endless belt when the drum unit is disposed in the pivot position.

2. The image forming apparatus according to claim 1, wherein the drum unit is slidably supported in the main body.

3. The image forming apparatus according to claim 1, further comprising a drum unit pivoting mechanism that pivots the drum unit between the initial position and the pivot position.

4. The image forming apparatus according to claim 3, wherein the drum unit pivoting mechanism includes:

a protruding part that protrudes outward from the second end in the axial direction; and

a contact part that is pivotable in a plane perpendicular to the axial direction and held in contact with the protruding part.

5. The image forming apparatus according to claim 1, wherein the main body comprises a reference part that adjusts a position of the drum unit in the main body;

wherein the second end contacts the reference part when the plurality of photosensitive drums are in contact with the endless belt.

6. The image forming apparatus according to claim 1, further comprising:

a casing that accommodate the black photosensitive drum, the casing having an arc-shaped protrusion sharing a central axis with the black photosensitive drum; and

a pressing member that presses the arc-shaped protrusion.

7. The image forming apparatus according to claim 6, wherein the casing includes a stopper that protrudes outward from the casing in the axial direction,

wherein the drum unit further includes a receiving portions that is receiving the stopper, and

wherein the pressing member presses the arc-shaped protrusion toward a point between the black photosensitive drum and the stopper.

8. The image forming apparatus according to claim 1, further comprising:

a transmitting mechanism that selectively transmits drive power to the plurality of photosensitive drums; and

a plurality of coupling members that correspond respectively to the plurality of photosensitive drums, each coupling member being selectively coupled to the corresponding photosensitive drum and having a coupling axis extending in the axial direction of the corresponding photosensitive drum, and

wherein each coupling member is uncoupled from the corresponding photosensitive drum when the corresponding photosensitive drum is separated from the endless belt.

9. The image forming apparatus according to claim 8, further comprising a mode setting unit that sets the image forming apparatus to one among a monochrome mode, a color mode, and a drum mounting mode, and

wherein the photosensitive drum is allowed to be mounted on or separated from the main body when the mode setting unit sets the image forming apparatus to the drum mounting mode.

10. The image forming apparatus according to claim 9, wherein the transmitting mechanism includes a switching member that is selectively movable to one of a first position corresponding to the drum mounting mode, a second position corresponding to the monochrome mode, and a third position corresponding to the color mode.

11. The image forming apparatus according to claim 10, wherein each photosensitive drum is uncoupled from the corresponding coupling member and contacts the endless belt when the switching member is disposed in the first position,

wherein, when the switching member is disposed in the second position, the black photosensitive drum is coupled with the corresponding coupling member and contacts the endless belt and each color photosensitive drum is uncoupled from the corresponding coupling member and is separated from the endless belt, and

wherein, when the switching member is disposed in the third position, each photosensitive drum is coupled with the corresponding coupling member and contacts the endless belt.

12. The image forming apparatus according to claim 10, further comprising a contact part that is pivotable in a plane perpendicular to the axial direction,

wherein the switching member includes a protruding part that protrudes toward the contact part,

wherein the contact part contacts the protruding part when the switching member is disposed in the second position, and

wherein the contact part is out of contact in the protruding part when the switching member is disposed in one of the first and third position.

13. An image forming apparatus comprising:

a main body;

an endless belt;

a plurality of photosensitive drums that are disposed in confrontation with the endless belt and are arranged in a first direction, each photosensitive drum having an axis extending in a second direction perpendicular to the first direction;

a mode setting unit that sets the image forming apparatus to one of a monochrome printing mode and a color printing mode;

a contacting/separating mechanism that controls at least one of the plurality of photosensitive drums to contact or separate from the endless in accordance with the set mode;

a transmitting mechanism that selectively transmits drive power to the plurality of photosensitive drums; and

a plurality of coupling members that correspond respectively to the plurality of photosensitive drums, each coupling member being selectively coupled to the corresponding photosensitive drum and having a coupling axis extending in the second direction of the corresponding photosensitive drum, and

wherein each coupling member is uncoupled from the corresponding photosensitive drum when the contacting/separating mechanism controls the corresponding photosensitive drum to separate from the endless belt.

14. The image forming apparatus according to claim 13, wherein the mode setting unit sets the image forming apparatus to one among the monochrome mode, the color mode, and a drum mounting mode, and

wherein the photosensitive drum is allowed to be mounted on or separated from the main body when the mode setting unit sets the image forming apparatus to the drum mounting mode.

15. The image forming apparatus according to claim 14, wherein the transmitting mechanism includes a switching member that is selectively movable to one of a first position corresponding to the drum mounting mode, a second position corresponding to the monochrome mode, and a third position corresponding to the color mode.

16. The image forming apparatus according to claim 15, wherein the plurality of photosensitive drums include a first photosensitive drum and second photosensitive drums,

wherein each photosensitive drum is uncoupled from the corresponding coupling member and contacts the endless belt when the switching member is disposed in the first position,

wherein, when the switching member is disposed in the second position, the first photosensitive drum is coupled with the corresponding coupling member and contacts the endless belt and each second photosensitive drum is uncoupled from the corresponding coupling member and is separated from the endless belt, and

wherein, when the switching member is disposed in the third position, each photosensitive drum is coupled with the corresponding coupling member and contacts the endless belt.

17. The image forming apparatus according to claim 14, further comprising a contact part that is pivotable in a plane perpendicular to the second direction,

wherein the switching member includes a protruding part that protrudes toward the contact part,

wherein the contact part contacts the protruding part when the switching member is disposed in the second position, and

wherein the contact part is out of contact in the protruding part when the switching member is disposed in one of the first and third position.

18. An image forming apparatus comprising:

a main body;

a plurality of photosensitive drums that include a black photosensitive drum and color photosensitive drums, black toner being used in the black photosensitive drum, each of yellow, magenta, and cyan toner being used in one of the color photosensitive drums, the black and color photosensitive drums being arranged in a first direction, each photosensitive drum having an axis extending in a direction perpendicular to the first direction,

a process frame that supports the color photosensitive drums in fixed positions and is detachably mounted on the main body, the process frame being inserted in a mounting direction to mount on the main body; and

a process unit that is detachably mounted in the process frame and supports the black photosensitive drum.

19. The image forming apparatus according to claim 18, wherein the process frame includes a pair of side plates that are disposed parallel to each other,

wherein each color photosensitive drum is rotatably supported between the pair of side plates, and

wherein the black photosensitive drum is rotatably and detachably supported between the pair of side plates.

20. The image forming apparatus according to claim 18, wherein the process frame has a first end and a second end that is disposed downstream in the mounting direction, the black photosensitive drum being disposed at a position nearest to the first end.