JP2019152842A - Image forming apparatus - Google Patents

Abstract

To prevent backlash of exposure heads in a state where a support member is separated from a drum unit.SOLUTION: An image forming apparatus (color printer 1) comprises: a drum unit 40 that includes photoconductor drums 41; exposure heads 50 that expose the photoconductor drums 41; developing cartridges 60 that store developer; and a support member 90 that supports the exposure heads 50 and developing cartridges 60 and is rotatable between an exposure position at which the exposure heads 50 can expose the photoconductor drums 41 and a separation position at which the exposure heads 50 are separated from the photoconductor drums 41. The support member 90 includes grooves 93A that movably support the exposure heads 50 and pressing members (head pressing members 98) that press the exposure heads 50 toward the photoconductor drums. The grooves 93A each have one end E5 closer to the photoconductor drum 41 and the other end E6 on the opposite side of one end E5. The exposure heads 50 are each in contact with one end E5 of the groove 93A when the support member 90 is located at the separation position.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an image forming apparatus including a photosensitive drum, an exposure head, and a developing cartridge.

  2. Description of the Related Art Conventionally, an image forming apparatus that includes a support member including an exposure head and a developing cartridge and a drum unit including a photosensitive drum is known (see Patent Document 1). In this technique, the support member is configured to be rotatable. The exposure head is attached under the support member via a spring. When the support member is rotated toward the drum unit, a boss provided on the exposure head is engaged with a positioning groove formed on the drum unit, whereby the exposure head is positioned with respect to the photosensitive drum.

JP 2013-134371 A

  However, in the prior art, since the exposure head is attached in a state of being suspended under the support member via a spring, the exposure head rattles when the support member is rotated away from the drum unit. Problem arises.

  Therefore, an object of the present invention is to prevent the exposure head from rattling when the support member is separated from the drum unit.

In order to solve the above problems, an image forming apparatus according to the present invention includes a drum unit including a photosensitive drum, an exposure head that exposes the photosensitive drum, a developing cartridge that stores a developer, the exposure head, and the developing cartridge. And a support member that can rotate between an exposure position where the exposure head can expose the photosensitive drum and a separation position where the exposure head is separated from the photosensitive drum.
The support member includes a groove that movably supports the exposure head, and a pressing member that presses the exposure head toward the photosensitive drum.
The groove has one end close to the photosensitive drum and the other end opposite to the one end.
The exposure head contacts the one end of the groove when the support member is located at the separation position.

  According to this configuration, when the support member is positioned at the separated position, the exposure head pressed by the pressing member contacts one end of the groove, so that the exposure head can be prevented from rattling at the separated position. .

  The drum unit has a positioning portion for positioning the exposure head, and when the support member is positioned at the exposure position, the exposure head contacts the positioning portion, and the groove You may leave | separate from the said one end.

  According to this, since the exposure head is positioned by the positioning unit of the drum unit, the exposure head can be accurately positioned with respect to the photosensitive drum. In addition, when the support member is located at the exposure position, the exposure head comes into contact with the positioning portion and is separated from one end of the groove, so that the exposure head can be favorably pressed against the positioning portion by the pressing member.

  The exposure head has a facing surface facing the developing cartridge, the developing cartridge has a facing surface facing the exposure head, the facing surface of the exposure head, and the facing surface of the developing cartridge. And may be parallel.

  According to this, for example, the capacity of the developing cartridge can be increased as compared with a structure in which the facing surface of the developing cartridge is inclined with respect to the facing surface of the exposure head.

  The optical axis of the exposure head may be along the normal line of the outer peripheral surface of the photosensitive drum.

  According to this, since the beam diameter can be made into a perfect circle, the image quality can be improved.

  The support member may have a first wall that partitions the developing cartridges.

  Further, the first wall may overlap the exposure head when viewed from a direction orthogonal to the rotation axis of the photosensitive drum and the predetermined direction.

  The pressing member may be disposed between the first wall and the exposure head.

  The support member may have two side walls sandwiching the developing cartridge in the rotation axis direction of the photosensitive drum, and the first wall may be joined to the two side walls.

  According to this, the rigidity of the support member can be increased.

  The support member has a second wall disposed between the developing cartridge closest to the rotation center of the support member and the rotation center, and the first wall is a first wall close to the photosensitive drum. And a second end opposite to the first end, and the second wall has a third end close to the photosensitive drum and a fourth end opposite to the third end. The fourth end may be located closer to the photosensitive drum than the second end.

  According to this, since the developing cartridge closest to the rotation center of the support member can be protruded to the rotation center side beyond the second wall lower than the first wall, it is closest to the rotation center of the support member. The capacity of the developing cartridge can be increased.

  The developing cartridge closest to the rotation center of the support member may have a larger capacity than other developing cartridges.

  The developing cartridge closest to the rotation center of the support member may contain a black developer.

  According to the present invention, it is possible to prevent the exposure head from rattling in a state where the support member is separated from the drum unit.

1 is a cross-sectional view illustrating a color printer according to an embodiment of the present invention. It is sectional drawing which shows the color printer of the state which opened the top cover. It is a figure which expands and shows the structure of the front side and rear side of a drum unit and a supporting member. A side view (a) showing the support member with the developing cartridge removed, a view (b) showing that the developing cartridge can be rotated with respect to the support member, and the second protrusion between the lever and the sub guide. It is a figure (c) which shows the state where a portion was pinched. It is a side view which shows a drum unit. It is a side view which shows a supporting member and a drum unit when a supporting member is located in an exposure position. FIG. 10 is a side view showing an operation of mounting the developing cartridge on the support member positioned at the exposure position. It is a side view which shows the state which the 1st convex part reached | attained the entrance of the 2nd guide of a drum unit. FIG. 9 is a side view showing a state where the first convex portion is moved to the photosensitive drum side along the second guide from the state of FIG. 8. It is a side view which shows the operation | movement which rotates a supporting member from a separation position to an exposure position. FIG. 5 is a cross-sectional view showing an embodiment in which the capacity of the developing cartridge closest to the rotation center of the support member is increased. It is sectional drawing which shows the form with which the optical axis of an exposure head is along the normal line of the outer peripheral surface of a photosensitive drum. It is a figure which shows the state which removed the drum unit from the main body housing | casing.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, a schematic configuration of the color printer 1 as an example of an image forming apparatus will be briefly described, and then a configuration of a characteristic part of the present invention will be described in detail.

  In the following description, directions will be described in the directions shown in FIG. That is, the left side in FIG. 1 is “front”, the right side is “rear”, the back side is “left”, and the front side is “right”. Further, the upper side in FIG. 1 is “upper” and the lower side is “lower”.

  As shown in FIG. 1, the color printer 1 includes a main body housing 10, a top cover 11, and a paper feeding unit 20 and an image forming unit 30 provided in the main body housing 10.

  The main body housing 10 has an opening 10A that opens upward. The top cover 11 is a cover that opens and closes the opening 10 </ b> A, and is disposed on the upper portion of the main body housing 10. The top cover 11 is provided so as to be rotatable with respect to the main body housing 10 about a rear rotation shaft 11A (see FIG. 2).

  The paper feed unit 20 includes a paper feed tray 21 that houses the paper P and a paper supply mechanism 22 that supplies the paper P from the paper feed tray 21 to the image forming unit 30. ing. The paper P in the paper feed tray 21 is separated one by one by the paper supply mechanism 22 and supplied to the image forming unit 30.

  The image forming unit 30 includes a drum unit 40, four exposure heads 50, four developing cartridges 60, a transfer unit 70, and a fixing unit 80. The four exposure heads 50 and the four developing cartridges 60 are supported by a support member 90 that can rotate with respect to the main body housing 10.

  The drum unit 40 includes four photosensitive drums 41, four charging rollers 42, and drum frames 43 that rotatably support the photosensitive drums 41 and the charging rollers 42. The four photosensitive drums 41 are arranged in the front-rear direction. Each photosensitive drum 41 has a rotation axis along the left-right direction. The charging roller 42 is a roller that charges the photosensitive drum 41, and is provided corresponding to each photosensitive drum 41.

  The exposure head 50 exposes the surface of the photosensitive drum 41 and is provided corresponding to each photosensitive drum 41. The exposure head 50 is disposed above the photosensitive drum 41, and has a light emitting element and an imaging lens at the lower end thereof.

  The developing cartridge 60 supplies developer to a portion of the photosensitive drum 41 exposed by the exposure head 50, and is provided corresponding to each photosensitive drum 41. The developing cartridge 60 mainly includes a developer accommodating portion 61 that accommodates the developer, and a developing roller 62 that supplies the developer in the developer accommodating portion 61 to the photosensitive drum 41. In the developer accommodating portion 61 of each developing cartridge 60, yellow, magenta, cyan, and black developers are accommodated in order from the front. In this embodiment, the capacity of each developing cartridge 60 is the same.

  The support member 90 is disposed above the drum unit 40. The support member 90 has an exposure position where the exposure head 50 can expose the photosensitive drum 41 (position in FIG. 1) and a separation position (position in FIG. 2) where the exposure head 50 is separated from the photosensitive drum 41 more than the exposure position. It is possible to rotate between them. In a state where the support member 90 is located at the separated position, the drum unit 40 is detachable from the main body housing 10. Each developing cartridge 60 can be attached to and detached from the support member 90.

  The transfer unit 70 is provided between the paper feed tray 21 and the drum unit 40. The transfer unit 70 includes a driving roller 71, a driven roller 72, an endless conveyance belt 73, and four transfer rollers 74. The conveyor belt 73 is stretched between the driving roller 71 and the driven roller 72. The outer surface of the conveyor belt 73 is in contact with the photosensitive drums 41, and the transfer rollers 74 are arranged inside the conveyor belts 73 so as to sandwich the conveyor belt 73 between the photosensitive drums 41.

  The fixing unit 80 is provided behind the transfer unit 70 and includes a heating roller 81 and a pressure roller 82 that is pressed toward the heating roller 81.

  In such an image forming unit 30, the surface of the photosensitive drum 41 is uniformly charged by the charging roller 42 and then exposed by the exposure head 50, whereby the electrostatic latent image based on the image data is formed on the photosensitive drum 41. An image is formed. Then, when the developer is supplied from the developing roller 62 to the photosensitive drum 41, the electrostatic latent image is visualized and a developer image is formed on the photosensitive drum 41.

  The developer images formed on the respective photosensitive drums 41 are sequentially superimposed and transferred onto the paper P on the conveying belt 73 by the respective transfer rollers 74. The sheet P on which the developer image has been transferred is conveyed between the heating roller 81 and the pressure roller 82, whereby the developer image is thermally fixed. Thereafter, the paper P is discharged from the main body housing 10 to the outside, and is placed on a paper discharge tray 11 </ b> B formed on the top surface of the top cover 11.

  Next, the drum frame 43 and the support member 90 of the drum unit 40 will be described in detail. Specifically, the structure for supporting the developing cartridge 60 and the exposure head 50 will be described in detail.

  As shown in FIG. 1, the drum frame 43 includes a front wall 431, two side walls 432 and 433, a rear wall 434, and a handle H1. The front wall 431 is disposed on the front side with respect to the plurality of photosensitive drums 41.

  The two side walls 432 and 433 are walls that rotatably support the photosensitive drums 41, and extend rearward from the left and right ends of the front wall 431. The rear wall 434 is a wall disposed on the rear side of the plurality of photosensitive drums 41 and connects the rear end portions of the side walls 432 and 433.

  The handle H1 is a cylindrical handle extending in the left-right direction, and both ends in the left-right direction are coupled to the upper end of the front wall 431 via two arm members 435. Each arm member 435 extends obliquely upward from the upper end of the front wall 431. The handle H1 is fixed to the tip of each arm member 435.

  The support member 90 includes a front wall 91, two side walls 92 and 93, a rear wall 94, and a handle H2. The front wall 91 is disposed on the front side with respect to the plurality of developing cartridges 60.

  The two side walls 92 and 93 are walls that support the developing cartridges 60 and the exposure heads 50, and extend rearward from the left and right ends of the front wall 91. The two side walls 92 and 93 sandwich the developing cartridges 60 and the exposure heads 50 in the left-right direction, that is, in the rotation axis direction of the photosensitive drum 41. The rear wall 94 is a wall disposed on the rear side of the plurality of developing cartridges 60 and connects the rear end portions of the side walls 92 and 93.

  At each end portion of the rear wall 94 in the left-right direction, one extending portion 95 that extends rearward is provided. A rear end portion of each extending portion 95 is rotatably supported by the main body housing 10. That is, the support member 90 is rotatable with respect to the main body housing 10 about one end in the horizontal direction, specifically, the front-rear direction.

  Specifically, each extending portion 95 has a rotation shaft 95A at the rear end portion for rotating the support member 90 between the exposure position and the separation position. Here, the rotation shaft 95 </ b> A may be a column that is rotatably supported by a hole formed in the main body housing 10, or may be rotated by a columnar boss provided in the main body housing 10. It may be a supported hole. The rotation shaft 95A is disposed at one end of the support member 90 in the front-rear direction.

  The handle H <b> 2 is a columnar handle extending in the left-right direction, and both end portions in the left-right direction are connected to the upper end portion of the front wall 91 via two handle support portions 96. Each handle support portion 96 extends forward from each end portion in the left-right direction at the upper end portion of the front wall 91. The handle H2 is fixed to the front end portion of each handle support portion 96.

  In addition, the support member 90 has three first walls 97 that partition the developing cartridges 60. Each first wall 97 is joined to two side walls 92 and 93. Specifically, the first wall 97 is joined to the side walls 92 and 93 by injection-molding resin in the same mold. The first wall 97 and the support member 90 excluding the first wall 97 may be manufactured by injection molding resin with separate molds. In this case, the first wall 97 may be joined to the side walls 92 and 93 by joining the first wall 97 and the support member 90 excluding the first wall 97 with an adhesive, a double-sided tape, or the like.

  Each first wall 97 has a first portion 97A extending in the vertical direction and a second portion 97B disposed at the upper end of the first portion 97A. The second part 97B is arranged so as to protrude forward from the first part 97A. The exposure head 50 is disposed below the second portion 97B and in front of the first portion 97A.

  That is, the second portion 97B overlaps the exposure head 50 when viewed in the vertical direction, that is, from the orthogonal direction orthogonal to the rotation axis of the photosensitive drum 41 and the alignment direction (predetermined direction) of the photosensitive drum 41. Further, the first portion 97A overlaps the exposure head 50 when viewed from the front-rear direction.

  The second portion 97B has an inclined surface F2. The inclined surface F2 is a surface on the rear side of the second portion 97B and is inclined obliquely downward and rearward. In a predetermined direction, a distance D1 from the upper end of the inclined surface F2 to the rotation shaft 95A is longer than a distance D2 from the lower end of the inclined surface F2 to the rotation shaft 95A. The width of the lower end of the second portion 97B in the predetermined direction is wider than the width of the upper end of the second portion 97B. 97 A of 1st site | parts are in the end (end by the side of the rotating shaft 95A) of 2nd site | part 97B, and are narrower in the predetermined direction than the 2nd site | part 97B. The exposure head 50 is in a space surrounded by the first part 97 </ b> A, the second part 97 </ b> B, and the side walls 92 and 93 in all directions (left and right upper rear). As described above, since the exposure head 50 is located in the part of the first wall 97, the support member 90 can be reduced in a predetermined direction, and the color printer 1 can be reduced in size in the predetermined direction.

  Further, the inclined surface F2 is connected to the rear surface of the first portion 97A. Thus, the front surface of the developing cartridge 60 disposed behind the first wall 97 is formed obliquely along the inclined surface of the second portion 97B, so that the capacity of the developing cartridge 60 can be increased.

  The rear wall 94 described above is an example of a second wall disposed between the developing cartridge 60 closest to the rotation center of the support member 90 and the rotation center, and has a shape similar to the first wall 97. Have. Specifically, the rear wall 94 has a first portion 94A extending in the vertical direction and a second portion 94B disposed at the upper end of the first portion 94A.

  The second part 94B is arranged to protrude forward from the first part 94A. The exposure head 50 is disposed below the second portion 94B and in front of the first portion 94A. The rear surface of the second portion 94B is an inclined surface that is inclined obliquely downward to the rear, and is connected to the rear surface of the first portion 94A.

  The upper end of the rear wall 94 is positioned below the upper end of each first wall 97. Specifically, the first wall 97 has a first end E1 close to the photosensitive drum 41 and a second end E2 opposite to the first end E1. The rear wall 94 has a third end E3 close to the photosensitive drum 41 and a fourth end E4 opposite to the third end E3. The fourth end E4 is located closer to the photosensitive drum 41 than the second end E2.

  The support member 90 includes four head pressing members 98 as an example of a pressing member that presses the exposure head 50 toward the photosensitive drum 41. The head pressing member 98 is, for example, a compression coil spring, and is disposed between the corresponding exposure head 50 and the second portion (97B or 94B).

  The exposure head 50 has a protrusion 51 that protrudes in the left-right direction from each side surface in the left-right direction. That is, the protrusions 51 are provided on one side surface and the other side surface of the exposure head 50 in the left-right direction, respectively. The protrusion 51 is formed in a cylindrical shape.

  Further, the exposure head 50 has a facing surface 52 that faces the developing cartridge 60 in a predetermined direction, specifically, in the front-rear direction. The facing surface 52 is orthogonal to the front-rear direction. The developing cartridge 60 has a facing surface 60 </ b> F that faces the exposure head 50. The facing surface 52 of the exposure head 50 is parallel to the facing surface 60F of the developing cartridge 60.

  As shown in FIG. 4A, the side wall 93 of the support member 90 has a groove 93A that supports the projection 51 of the exposure head 50 so as to be movable. Since the right side wall 93 and the left side wall 92 have the same structure, the structure of the right side wall 93 will be described as a representative, and the description of the left side wall 92 will be omitted.

  The groove 93A has one end E5 close to the photosensitive drum 41 and the other end E6 opposite to the one end E5. The protrusion 51 of the exposure head 50 contacts one end E5 of the groove 93A when the support member 90 is located at the separation position. Here, since FIG. 4 is a single view of the support member 90, the position of the protrusion 51 is located at the same position as when the support member 90 is located at the separated position.

  The developing cartridge 60 has a first convex portion C1, a second convex portion C2, and a third convex portion C3 that protrude from the left and right side surfaces in the left-right direction, that is, the rotation axis direction of the photosensitive drum 41. That is, the first convex portion C1, the second convex portion C2, and the third convex portion C3 are respectively provided on one side surface and the other side surface of the developing cartridge 60 in the left-right direction.

  The 1st convex part C1, the 2nd convex part C2, and the 3rd convex part C3 are each formed in the column shape. In particular, the first convex portion C <b> 1 is formed in a cylindrical shape with the rotation axis of the developing roller 62 as the center. The first convex portion C1 may be a rotating shaft of the developing roller 62 or a bearing that supports the rotating shaft.

  The second convex portion C2 is disposed at a position farther from the photosensitive drum 41 than the first convex portion C1. The third convex portion C3 is disposed at a position farther from the photosensitive drum 41 than the second convex portion C2.

  The side wall 93 of the support member 90 includes a cartridge guide G1 that guides the second convex portion C2 and the third convex portion C3 of the developing cartridge 60 when the developing cartridge 60 is mounted on the supporting member 90. The cartridge guide G1 includes a main guide G11 that guides the second convex portion C2 and the third convex portion C3, and a sub guide G12 that is located at the lower end portion of the main guide G11.

  The main guide G11 is a groove formed in the side wall 93, and extends in a substantially vertical direction, specifically, in a direction slightly inclined forward and backward with respect to the vertical direction. In other words, the main guide G11 extends in a third direction different from the second direction, which is a direction in which a second guide G22 (see FIG. 5) described later extends. The main guide G11 opens upward, extends obliquely downward from the upper end of the side wall 93, and is connected to the sub guide G12.

  The sub guide G12 is a groove formed in the side wall 93 and has a lower surface F1 that is a surface on the photosensitive drum 41 side. In the direction orthogonal to the third direction, the length L2 of the sub guide G12 is larger than the length L1 of the main guide G11. Moreover, the diameter of the 2nd convex part C2 is smaller than the 3rd convex part C3. Thereby, in the direction orthogonal to the third direction, the clearance between the sub guide G12 and the second convex portion C2 is larger than the clearance between the main guide G11 and the third convex portion C3. Therefore, as shown in FIG. 4B, in the state where the developing cartridge 60 is mounted on the support member 90, the developing cartridge 60 can rotate around the third convex portion C3.

  Returning to FIG. 4A, the support member 90 includes a cartridge pressing member 100 that presses the developing cartridge 60 toward the photosensitive drum 41. Here, in FIG. 4, for convenience, the cartridge pressing member 100 is disposed outside the side wall 93 in the left-right direction, but actually, the cartridge pressing member 100 is disposed inside the side wall 93 in the left-right direction. .

  The cartridge pressing member 100 includes a lever 110 that is rotatably supported by the side wall 93 and a spring 120 that biases the lever 110.

  The lever 110 includes a rotation shaft part 111, a first arm part 112, a second arm part 113, a first pressing part 114, and a second pressing part 115. The rotation shaft portion 111 is disposed after the upper end portion of the corresponding main guide G11.

  The first arm portion 112 extends toward the lower end of the support member 90 when the support member 90 is located at the separated position, and a part of the first arm portion 112 is disposed in the main guide G11. The second arm portion 113 extends toward the rear end of the support member 90 when the support member 90 is positioned at the separated position, and a spring 120 is connected to the rear end portion.

  The first pressing portion 114 extends toward the rear end of the support member 90 when the support member 90 is located at the separation position. The second pressing portion 115 extends toward the lower end of the support member 90 when the support member 90 is located at the separation position.

  The first pressing portion 114 presses the second convex portion C2 when the support member 90 is positioned at the exposure position (see FIG. 10). Further, as shown in FIG. 4C, the first pressing portion 114 is connected to the lower surface F1 that is the surface on the photosensitive drum 41 side of the sub guide G12 when the support member 90 is located at the separation position. Two convex portions C2 are sandwiched. The second pressing portion 115 is a stopper for preventing the lever 110 from being detached from the second convex portion C2 when the support member 90 is located at the separation position.

  The spring 120 is, for example, a tension coil spring, and urges the tip of the second arm portion 113 to be pulled downward and obliquely downward. In the state shown in FIG. 4A, the spring 120 has a natural length. However, the present invention is not limited to this. For example, when the lever 110 is restricted by the stopper (not shown) from rotating clockwise from the position shown in FIG. The lever 110 may be constantly energized.

  As shown in FIG. 5, the drum frame 43 of the drum unit 40 includes a first guide G21 extending in the vertical direction as an example of the first direction, and a second guide G22 extending in a second direction different from the vertical direction. The first guide G21 and the second guide G22 are configured to guide the first convex portion C1 of the developing cartridge 60 when the support member 90 that supports the developing cartridge 60 moves from the separation position to the exposure position. The first guide G21 and the second guide G22 also guide the first convex portion C1 when the developing cartridge 60 is mounted on the support member 90 located at the exposure position and the drum unit 40 below the support member 90. It is configured.

  The first guide G21 is a groove formed on the side wall 433 of the drum frame 43 and opens upward. The first guide G21 is formed to become wider as it goes upward. Since the right side wall 433 and the left side wall 432 have the same structure, the structure of the right side wall 433 will be representatively described below, and the description of the left side wall 432 will be omitted.

  The second guide G22 is a groove formed in the side wall 433 of the drum frame 43, and is configured to guide the first convex portion C1 of the developing cartridge 60 guided by the first guide G21 toward the photosensitive drum 41. ing. Specifically, the second guide G22 extends obliquely downward from the lower end of the first guide G21.

  The second guide G22 extends along the normal line of the outer peripheral surface of the photosensitive drum 41. In other words, the second guide G22 overlaps the rotation center of the photosensitive drum 41 when viewed from the second direction.

  Further, the side wall 433 of the drum frame 43 has a positioning portion PP for positioning the exposure head 50. The positioning portion PP is a notch having a V-shaped cross-sectional view, and as shown in FIG. At this time, the protrusion 51 of the exposure head 50 is configured to be separated from the one end E5 of the groove 93A. That is, in the process of moving the support member 90 from the separation position to the exposure position, when the protrusion 51 supported by the one end E5 of the groove 93A comes into contact with the positioning portion PP, the protrusion 51 cannot be lowered any further. Therefore, when the support member 90 is further lowered thereafter, one end E5 of the groove 93A is moved downward with respect to the protrusion 51, so that the protrusion 51 is separated from the one end E5 of the groove 93A at the exposure position.

  When the support member 90 is located at the exposure position, the support member 90 and the first guide G21 overlap with each other when viewed from the left-right direction, that is, the rotation axis direction of the photosensitive drum 41. Specifically, the left and right side walls 92 and 93 of the support member 90 are disposed on the outer side in the left and right direction with respect to the left and right side walls 432 and 433 of the drum frame 43. The front wall 91 of the support member 90 may be appropriately provided with notches for escaping the left and right side walls 432 and 433 of the drum frame 43.

  As shown in FIG. 7, the tip of the first convex portion C1 of the developing cartridge 60 described above is inward of the left and right side walls 92, 93 of the support member 90 in the left-right direction, and the first guide G21. And it is located in the position which can be engaged with the 2nd guide G22. Further, the second convex portion C2 and the third convex portion C3 of the developing cartridge 60 protrude outward in the left-right direction from the first convex portion C1, and are cartridge guides formed on the left and right side walls 92, 93 of the support member 90. It can be engaged with G1.

  As shown in FIGS. 8 and 9, when the first convex portion C1 is positioned on the second guide G22, the second convex portion C2 is positioned on the sub guide G12, and the third convex portion C3 is on the main guide G11. It is supposed to be located. As shown in FIG. 9, when the support member 90 to which the developing cartridge 60 is mounted is located at the exposure position, the second convex portion C2 is in contact with the lever 110 and the sub-guide G12 on the photosensitive drum 41 side. It is separated from the lower surface F1, which is the surface of the.

  Further, as shown in FIG. 10, in the process of rotating the support member 90 on which each developing cartridge 60 is mounted from the separation position toward the exposure position, the support member 90 among the plurality of first protrusions C1. The first convex portion C1 closest to the center of rotation is in contact with the first guide G21 earlier than the other first convex portions C1. Thereby, when the support member 90 is rotated downward, the developing cartridge 60 closest to the rotation center of the support member 90 is rotated earlier than the other developing cartridges 60. For this reason, in the process of rotating the support member 90 to which each developing cartridge 60 is mounted from the separated position toward the exposure position, the rotation center of the support member 90 is the most of the plurality of second convex portions C2. It is spaced apart from the lower surface F1 of the sub guide G12 in order from the closest second convex portion C2 (see FIGS. 5B and 5C).

Next, functions and effects of the support member 90 and the drum unit 40 according to the present embodiment will be described.
As shown in FIG. 7, when the developing cartridge 60 is inserted into the support member 90 with the support member 90 positioned at the exposure position, first, the second convex portion C2 and the third convex portion are caused by the main guide G11. C3 is guided. As described above, the two convex portions C2 and C3 are guided by the main guide G11, so that the developing cartridge 60 can be inserted with the posture kept constant.

  Thereafter, the first convex portion C1 of the developing cartridge 60 is placed in the first guide G21 of the drum unit 40, and the first convex portion C1 is guided toward the second guide G22 by the first guide G21. As shown in FIG. 8, when the first convex portion C1 reaches the second guide G22 and is located at the entrance (upper end) of the second guide G22, the second convex portion C2 is located at the sub guide G12, and The 3rd convex part C3 is located in the main guide G11. Therefore, in this state, the developing cartridge 60 can be rotated around the third convex portion C3.

  In the process in which the second convex portion C2 moves along the main guide G11, the second convex portion C2 rotates the lever 110 counterclockwise in the figure against the biasing force of the spring 120. When the second convex portion C2 gets over the corner between the first arm portion 112 and the first pressing portion 114 of the lever 110, the lever 110 is rotated clockwise by the biasing force of the spring 120, and the first pressing portion C2 is rotated. The portion 114 is disposed on the second convex portion C2.

  Thereafter, when the developing cartridge 60 is further pushed downward, the first convex portion C1 is guided rearward and obliquely downward by the second guide G22, whereby the developing cartridge 60 is rotated counterclockwise in the drawing with the third convex portion C3 as the center. To turn. That is, since the developing cartridge 60 is rotatable about the third convex portion C3, the first convex portion C1 moves smoothly along the second guide G22.

  As shown in FIG. 9, when the developing roller 62 of the developing cartridge 60 comes into contact with the photosensitive drum 41, the first pressing portion 114 of the lever 110 presses the second convex portion C2 downward, thereby causing the first convex portion. C1 is pushed obliquely downward and rearward along the second guide G22, and the developing roller 62 is pushed toward the photosensitive drum 41. When the developing cartridge 60 is removed from the support member 90, the developing cartridge 60 may be operated and pulled out by an operation reverse to the operation described above.

  As shown in FIG. 10, when the support member 90 on which each developing cartridge 60 is mounted is rotated from the separated position toward the exposure position, the developing cartridge closest to the rotating shaft 95 </ b> A among the plurality of developing cartridges 60. The 60 first convex portions C1 come into contact with the first guide G21 of the drum unit 40 before the other three first convex portions C1. As a result, in the process of rotating the support member 90 on which each developing cartridge 60 is mounted from the separated position toward the exposure position, as shown in the order of FIG. 4C and FIG. The convex portion C2 is separated from the lower surface F1 of the sub guide G12 in order from the second convex portion C2 closest to the rotation shaft 95A.

  Similarly, when the support member 90 is rotated from the separated position toward the exposure position, the projection 51 of the exposure head 50 that is closest to the rotation axis 95A among the plurality of exposure heads 50 becomes the other projection 51. Prior to this, the positioning unit PP of the drum unit 40 is contacted. Thereby, in the process of rotating the support member 90 from the separation position toward the exposure position, the protrusions 51 are sequentially separated from the end E5 of the groove 93A in order from the protrusion 51 closest to the rotation shaft 95A. (See FIG. 6).

According to the above, the following effects can be obtained in the present embodiment.
Even in the structure in which the guides bent in the drum unit 40, that is, the first guide G21 and the second guide G22 extending in different directions are provided, when the first protrusion C1 is positioned on the second guide G22, the second protrusion Since the part C2 is located on the sub guide G12 and the third convex part C3 is located on the main guide G11, the first convex part C1 and the second convex part C2 are rotated around the third convex part C3. be able to. Therefore, the first convex portion C1 can be smoothly moved along the second guide G22 extending in a direction different from the first guide G21, so that the developing cartridge 60 can be favorably positioned with respect to the photosensitive drum 41. it can.

  When the support member 90 is located at the separated position, the second convex portion C2 is sandwiched between the lever 110 and the sub guide G12, so that the developing cartridge 60 does not rattle with respect to the support member 90 at the separated position. Can be suppressed.

  When the support member 90 is positioned at the exposure position, the second convex portion C2 is in contact with the lever 110 and is separated from the lower surface F1 of the sub guide G12, so that the developing roller 62 of the developing cartridge 60 is moved to the photosensitive drum. 41 can be pressed well.

  In the process of rotating the support member 90 from the separation position toward the exposure position, the structure is such that the second protrusion C2 closest to the rotation center of the support member 90 is sequentially separated from the lower surface F1 of the sub guide G12. By doing so, the reaction force transmitted from the support member 90 to the user can be gradually increased, so that the operability of the support member 90 can be improved.

  When the support member 90 is located at the separated position, the exposure head 50 being pressed by the head pressing member 98 contacts the one end E5 of the groove 93A, so that the exposure head 50 can be prevented from rattling at the separated position. .

  Since the exposure head 50 is positioned by the positioning portion PP of the drum unit 40, the exposure head 50 can be accurately positioned with respect to the photosensitive drum 41. Further, when the support member 90 is positioned at the exposure position, the exposure head 50 comes into contact with the positioning portion PP and is separated from the one end E5 of the groove 93A. Can be pressed against.

  Since the facing surface 52 of the exposure head 50 and the facing surface 60F of the developing cartridge 60 are parallel to each other, for example, the developing cartridge 60 has a facing surface that is inclined with respect to the facing surface of the exposing head. The capacity can be increased.

  Since the first wall 97 is joined to the two side walls 92 and 93, the rigidity of the support member 90 can be increased.

  In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below. In the following description, the same reference numerals are given to members having substantially the same structure as in the above embodiment, and the description thereof is omitted.

  In the embodiment, the capacity of each developing cartridge 60 is the same, but the present invention is not limited to this. For example, as shown in FIG. 11, the capacity of the developing cartridge 60 closest to the rotation shaft 95 </ b> A (rotation center) of the support member 90 may be larger than that of the other developing cartridges 60.

  Specifically, since the upper end of the rear wall 94 is positioned below the upper end of each first wall 97 as described above, the position of the upper surface of each developing cartridge 60 is kept constant while the rear wall 94 The upper part of the front developing cartridge 60 can extend beyond the upper end of the rear wall 94 to the rear. The developing cartridge 60 closest to the rotation shaft 95A of the support member 90 contains the black developer as described above. Therefore, it is possible to increase the capacity of the developing cartridge 60 that accommodates the black developer that consumes the largest amount of consumption, thereby improving user convenience.

  As shown in FIG. 12, the optical axis of the exposure head 50 may be along the normal line of the outer peripheral surface of the photosensitive drum 41. Specifically, the exposure head 50 may be arranged so that the extension line of the optical axis of the exposure head 50 passes through the rotation center of the photosensitive drum 41. According to this, since the diameter of the beam emitted from the exposure head 50 on the outer peripheral surface of the photosensitive drum 41 can be made a perfect circle, the image quality can be improved.

  In the embodiment, the compression coil spring is exemplified as the pressing member. However, the present invention is not limited to this, and the pressing member may be a pressing spring other than the compression coil spring such as a plate spring or a torsion spring. A tension spring may be used.

  In the above embodiment, the number of the photosensitive drums 41, the exposure heads 50, and the developing cartridges 60 provided in the drum unit 40 and the support member 90 is four. However, the present invention is not limited to this, and the photosensitive drums, the exposure heads, and the developing cartridges. The number may be one each or a plurality other than four.

  In the above-described embodiment, the present invention is applied to the color printer 1, but the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as monochrome printers, copiers, and multifunction machines. Good.

  You may implement combining each element demonstrated by embodiment mentioned above and the modification arbitrarily.

In the embodiment, the color printer 1 has the following configuration.
As shown in FIG. 13, the drum unit 40 includes four photosensitive drums 41, four charging rollers 42, and drum frames 43 that rotatably support the photosensitive drums 41 and the charging rollers 42. The support member 90 is disposed above the drum unit 40. The support member 90 has an exposure position where the exposure head 50 can expose the photosensitive drum 41 (position in FIG. 1) and a separation position (position in FIG. 2) where the exposure head 50 is separated from the photosensitive drum 41 than the exposure position. It is possible to rotate between them. In a state where the support member 90 is located at the separated position, the drum unit 40 is detachable from the main body housing 10. Each developing cartridge 60 can be attached to and detached from the support member 90.

  Here, in the prior art (Japanese Patent Laid-Open No. 2013-134371), there are four drum units each including a photosensitive drum, and the four drum units can be individually attached to and detached from the main body housing. Therefore, in this technique, when a jam that leaves a sheet on the belt occurs, it is necessary to individually remove the four drum units, so that the jam handling operation is troublesome for the user.

  On the other hand, in the present invention, even when a jam that leaves the paper P on the belt 73 occurs, the paper P can be removed from the belt 73 only by removing one drum unit 40. The burden on the user related to the removal can be reduced.

DESCRIPTION OF SYMBOLS 1 Color printer 40 Drum unit 41 Photosensitive drum 50 Exposure head 60 Developing cartridge 90 Support member 93A Groove 98 Head pressing member E5 One end E6 Other end

Claims (11)

A drum unit having a photosensitive drum;
An exposure head for exposing the photosensitive drum;
A developer cartridge containing developer;
A support member that supports the exposure head and the developing cartridge, and is rotatable between an exposure position where the exposure head can expose the photosensitive drum and a separation position where the exposure head is separated from the photosensitive drum; With
The support member is
A groove that movably supports the exposure head, and a pressing member that presses the exposure head toward the photosensitive drum,
The groove has one end close to the photosensitive drum and the other end opposite to the one end.
The image forming apparatus, wherein the exposure head is in contact with the one end of the groove when the support member is located at the separated position. The drum unit has a positioning portion for positioning the exposure head,
2. The image forming apparatus according to claim 1, wherein when the support member is positioned at the exposure position, the exposure head contacts the positioning portion and is separated from the one end of the groove. The exposure head has a facing surface facing the developing cartridge;
The developing cartridge has a facing surface facing the exposure head;
The image forming apparatus according to claim 1, wherein a facing surface of the exposure head and a facing surface of the developing cartridge are parallel to each other.   The image forming apparatus according to claim 3, wherein an optical axis of the exposure head is along a normal line of an outer peripheral surface of the photosensitive drum.   The image forming apparatus according to claim 4, wherein the support member has a first wall that partitions the developing cartridges.   The image forming apparatus according to claim 5, wherein the first wall overlaps the exposure head when viewed from an orthogonal direction orthogonal to the rotation axis of the photosensitive drum and the predetermined direction.   The image forming apparatus according to claim 6, wherein the pressing member is disposed between the first wall and the exposure head. The support member has two side walls that sandwich the developing cartridge in the rotation axis direction of the photosensitive drum,
The image forming apparatus according to claim 5, wherein the first wall is joined to the two side walls. The support member has a second wall disposed between the developing cartridge closest to the rotation center of the support member and the rotation center,
The first wall has a first end close to the photosensitive drum and a second end opposite to the first end,
The second wall has a third end close to the photosensitive drum and a fourth end opposite to the third end,
9. The image forming apparatus according to claim 5, wherein the fourth end is located closer to the photosensitive drum than the second end.   The image forming apparatus according to claim 9, wherein the developing cartridge closest to the rotation center of the support member has a larger capacity than the other developing cartridges.   The image forming apparatus according to claim 10, wherein the developing cartridge closest to the rotation center of the support member contains a black developer.

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