Image forming apparatus

Abstract

An image forming apparatus is provided with a rotary image bearing member; a charging roller for charging the outer circumferential surface of the image bearing member by rotating in contact with the image bearing member; a brush roller for cleaning adhered matters on the outer circumferential surface of the charging roller by being held in contact with the charging roller due to its own weight and rotating; a driving mechanism for drivingly rotating the brush roller to have a linear velocity difference to the charging roller; and a moving mechanism for reciprocating the brush roller along the longitudinal direction thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic section showing the internal construction of a printer according to one embodiment of the invention,

FIGS. 2A to 2C are views showing a charging roller and a brush roller, wherein FIG. 2A is a side view, FIG. 2B is a front view and FIG. 2C is a side view showing inclined directions of bristles of the brush roller,

FIG. 3 is a perspective view showing a first assembled state of the charging roller and the brush roller,

FIG. 4 is a perspective view showing a second assembled state of the charging roller and the brush roller,

FIG. 5 is a perspective view showing a third assembled state of the charging roller and the brush roller,

FIG. 6 is an enlarged view of the right side of FIG. 3,

FIG. 7 is an enlarged view of the left side of FIG. 3,

FIG. 8 is an enlarged view showing a state where a gear is assembled in the state of FIG. 6,

FIG. 9 is a perspective view showing the state of FIG. 7 when viewed from a disk cam side,

FIG. 10 is a front view showing the state of FIG. 9,

FIG. 11 is a perspective view showing a state where a mounting member is assembled in the state of FIG. 9,

FIGS. 12A and 12B are perspective views of the disk cam when viewed from one lateral side and when viewed from the other lateral side, respectively, and

FIGS. 13A and 13B are perspective views of a casing member when viewed from one lateral side and when viewed from the other lateral side, respectively.

Claims

1. An image forming apparatus, comprising: a rotary image bearing member;a charging roller for charging the outer circumferential surface of the image bearing member by rotating in contact with the image bearing member;a brush roller for cleaning adhered matters on the outer circumferential surface of the charging roller by being held in contact with the charging roller due to its own weight and rotating;a driving mechanism for drivingly rotating the brush roller to have a linear velocity difference to the charging roller; anda moving mechanism for reciprocating the brush roller along the longitudinal direction thereof.

2. An image forming apparatus according to claim 1, further comprising: bearing members for supporting the brush roller, andshaft portions at the opposite ends of the brush roller,wherein the brush roller is disposed substantially right above the charging roller, andthe bearing members are formed with longer shaft holes long in vertical direction for holding the shaft portions rotatably, vertically movably and reciprocally movably along longitudinal direction.

3. An image forming apparatus according to claim 1, wherein the driving mechanism includes: a first gear concentrically mounted on one end of the brush roller, anda second gear synchronously rotatable with the charging roller, engageable with the first gear and having a different number of teeth than the first gear.

4. An image forming apparatus according to claim 3, wherein: the image bearing member is a photoconductive drum rotatable about its central axis and including a third gear concentrically mounted at one end of the photoconductive drum,the charging roller is synchronously rotatable with the photoconductive drum, andthe third gear is engaged with the second gear.

5. An image forming apparatus according to claim 4, wherein: the second gear moves following the movement of the brush roller, andthe depth and width of engagement of the second and third gears are set to take up any movement of the brush roller within a movable range thereof.

6. An image forming apparatus according to claim 1, wherein the moving mechanism includes: a disk cam provided at one end of the brush roller and inclined with respect to a longitudinal direction,a casing member having holding projections for holding a part of the outer periphery of the disk cam from opposite sides along longitudinal direction, anda supporting member for supporting the casing member in such a manner as not to permit a movement of the casing member along longitudinal direction.

7. An image forming apparatus according to claim 1, wherein the fineness of bristles of the brush roller and the density thereof are preferably set within a range of 1 to 10 T (decitex) and within a range of 150 to 300 kF/inch2, respectively.

8. An image forming apparatus according to claim 1, wherein inclining directions of the bristles of the brush roller with respect to the charging roller conform to a rotating direction of the charging roller.