JP2019152843A - Image forming apparatus - Google Patents

Abstract

To accurately determine the position of a drum unit including a plurality of photoconductor drums with respect to a body housing.SOLUTION: An image forming apparatus (color printer 1) comprises: a drum unit 40 that includes a plurality of photoconductor drums 41 arranged in a predetermined direction; a support member 90 that supports 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; a positioning part SP that determines the position of the drum unit 40 in the predetermined direction; and a first pressing member P1 that presses the drum unit 40 against the positioning part SP. When the support member 90 is rotated to the exposure position, the first pressing member P1 is pressed by the support member 90, and the first pressing member P1 presses the drum unit 40. The pressing force of the first pressing member P1 has a component in the predetermined direction larger than a component in the orthogonal direction orthogonal to the predetermined direction and the rotation axis direction of the photoreceptor drums 41.SELECTED DRAWING: Figure 7

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 is known that includes a support member including a plurality of exposure heads and a plurality of developing cartridges, a plurality of drum cartridges including a photosensitive drum, and a belt that contacts the plurality of photosensitive drums. (See Patent Document 1). In this technique, the support member is configured to be rotatable, and after the support member is rotated upward, the drum cartridge under the support member can be replaced.

JP 2013-134371 A

  By the way, in order to facilitate replacement of a plurality of photosensitive drums, it is conceivable to provide a plurality of photosensitive drums in one drum unit. However, in this case, when the drum unit is positioned on the main body housing, the plurality of photosensitive drums and the belt are rubbed to increase the frictional resistance, and the drum unit may not be accurately positioned.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can accurately position a drum unit including a plurality of photosensitive drums with respect to a main body housing.

In order to solve the above problems, an image forming apparatus according to the present invention includes a drum unit including a plurality of photosensitive drums arranged in a predetermined direction, an exposure head that exposes the photosensitive drum, a developing cartridge that stores a 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; A belt that contacts the plurality of photosensitive drums, a main body housing having a positioning portion for positioning the drum unit in the predetermined direction, and a first pressing member that presses the drum unit against the positioning portion.
When the support member is rotated from the separated position to the exposure position, the first pressing member presses the drum unit by the first pressing member being pressed by the support member.
In the pressing force of the first pressing member, the component in the predetermined direction is larger than the component in the orthogonal direction orthogonal to the predetermined direction and the rotation axis direction of the photosensitive drum.

  According to this configuration, the drum unit is pressed against the positioning unit against the frictional force of the belt by the force applied to the support member when the support member is moved from the separation position to the exposure position and the pressing force of the first pressing member. Therefore, the drum unit can be accurately positioned with respect to the main body housing.

  The main body housing includes a second pressing member that presses the drum unit against the positioning unit, and a guide that extends toward the positioning unit, and the drum unit is guided by the guide, and the positioning unit The pressing force of the second pressing member may have a component in the predetermined direction larger than a frictional force generated between the reference shaft and the guide.

  According to this, since the drum unit can be pressed against the positioning portion against the frictional force of the belt by the first pressing member and the second pressing member, the drum unit can be accurately positioned with respect to the main body housing. . In addition, since the force of the first pressing member can be reduced as compared with the structure in which the drum unit is pressed only by the first pressing member, the first member added to the user who operates the support member when setting the support member at the exposure position. The reaction force from the pressing member can be reduced.

  In addition, the image forming apparatus includes a cover that opens and closes an opening formed in the main body casing, and a rotation that is rotatably supported by the main body casing and that can contact the cover and the second pressing member. A member, and when the cover is closed, the cover contacts the rotating member and the rotating member rotates, so that the rotating member directs the second pressing member toward the drum unit. May be pressed.

  Accordingly, the force for closing the cover can be used as a force for positioning the drum unit.

  Further, the rotating member may press the second pressing member along the predetermined direction.

  Further, when the support member is moved from the separated position to the exposure position, the first pressing member may contact the drum unit prior to the exposure head and the developing cartridge.

  According to this, the first pressing member contacts the drum unit and presses the drum unit before the frictional force generated when the exposure head or the developing cartridge contacts the drum unit, so that the drum unit can be positioned more accurately. Can do.

  The first pressing member includes a spring provided on the support member and a lock member rotatably provided on the main body housing, and the support member is rotated from the separated position to the exposure position. In this case, the lock member may press the reference shaft against the positioning portion by the support member pressing the lock member via the spring.

  The lock member may be connected to the spring.

  According to this, when the support member is moved from the exposure position to the separation position, the lock member connected to the spring is rotated and disengaged from the reference axis, so that the user can save time and effort to remove the lock. Can be improved.

  The positioning portion is a recess, and the lock member is located at a first position that closes an opening of the positioning portion when the support member is located at the exposure position, and the support member is located at the separation position. When positioned at the second position, it may be positioned at a second position where the opening of the positioning portion is opened.

  According to this, when the drum unit is mounted on the main body housing, the lock member is positioned at a position where the opening of the positioning unit is opened, so that the user can easily see the positioning unit, so that the operability can be improved. it can.

  Moreover, the said 1st press member and the said 2nd press member may be provided one each on the one side and the other side of the said rotating shaft direction with respect to the said drum unit.

  According to this, the drum unit can be pressed in a balanced manner by the first pressing members and the like disposed on both sides in the rotation axis direction.

  According to the present invention, it is possible to accurately position a drum unit including a plurality of photosensitive drums with respect to the main body housing.

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. It is a figure which shows the structure of the left side of a main body housing | casing. It is a figure which shows a state when attaching a drum unit to a main body housing | casing starts. It is a figure which shows the state which the to-be-pressed part of the drum unit contacted the 2nd press member. It is a figure which shows the state which rotates a support member to an exposure position from a separation position.

  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 as an example of a cover, and a paper feeding unit 20 and an image forming unit 30 provided in the main body housing 10. Yes.

  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 as an example of the predetermined 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, a conveyance belt 73 as an example of a belt, and four transfer rollers 74. The conveyor belt 73 is an endless belt, and 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 and the structure for positioning the drum unit 40 in the main body housing 10 will be described in detail.

  As shown in FIG. 3, 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. 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 rear surface of the second portion 97B is an inclined surface that is inclined obliquely downward and 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.

  Further, the rear wall 94 described above is a 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. . 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 that press 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.

  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 notch PP for positioning the exposure head 50. The notch PP is a notch having a V shape in a 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, if the protrusion 51 supported by the one end E5 of the groove 93A contacts the notch 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. 6, the tip end portion 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.

  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 positioned on the main guide G11. When the support member 90 to which the developing cartridge 60 is mounted is positioned at the exposure position, the second convex portion C2 is in contact with the lever 110 and from the lower surface F1 that is the surface of the sub guide G12 on the photosensitive drum 41 side. It is designed to be separated.

  Further, 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 closest to the rotation center of the support member 90 among the plurality of second convex portions C2. In order from the second convex portion C2, the sub guide G12 is separated from the lower surface F1.

  Returning to FIG. 5, the side wall 433 of the drum frame 43 includes a reference axis A <b> 1 for positioning the drum unit 40 with respect to the main body housing 10, and a pressed portion A <b> 2 pressed by a second pressing member P <b> 2 described later. Have. The reference axis A1 and the pressed part A2 are similarly provided on the left side wall 432 as well.

  The reference axis A <b> 1 is a columnar protrusion and is disposed on the rear side of the lower end portion of the side wall 433. The reference axis A1 protrudes outward from the side wall 433 in the left-right direction.

  The pressed portion A <b> 2 is a columnar protrusion and is disposed on the front side of the lower end portion of the side wall 433. The pressed portion A2 protrudes outward from the side wall 433 in the left-right direction.

  As shown in FIG. 7, the main body housing 10 includes a positioning portion SP, a main body guide G3, a first pressing member P1, a second pressing member P2, and a rotating member R. The positioning portion SP, the main body guide G3, the first pressing member P1, the second pressing member P2, and the rotating member R are in the left-right direction, that is, on one side and the other side in the rotational axis direction of the photosensitive drum 41 with respect to the drum unit 40. One by one. In the following description, the structure on the left side of the main body housing 10 will be described, and the structure on the right side is the same, so the description will be omitted.

  The positioning part SP is a part for positioning the drum unit 40 in a predetermined direction, that is, the front-rear direction, and is formed integrally with the main body guide G3. The positioning portion SP is a recess that opens forward, and includes a horizontal portion SP1 and an inclined portion SP2.

  The horizontal portion SP1 is a portion that supports the reference axis A1 of the drum unit 40 from below, and extends along the front-rear direction. The horizontal part SP1 is formed integrally with the main body guide G3.

  The inclined portion SP2 is a portion describing the backward movement of the reference axis A1, and extends obliquely upward and forward from the rear end of the horizontal portion SP1. The reference axis A1 is positioned by the positioning portion SP by contacting the inclined portion SP2.

  The main body guide G3 is a part for guiding the drum unit 40 toward the positioning portion SP. The main body guide G3 includes a first main body guide G31, a second main body guide G32, a third main body guide G33, and a fourth main body guide G34.

  The first main body guide G31 is a portion that supports the pressed portion A2 from below, and extends along the front-rear direction. The first main body guide G31 is formed integrally with the horizontal portion SP1 and extends forward from the horizontal portion SP1.

  The second main body guide G32 extends upward from the front end of the first main body guide G31. The third main body guide G33 extends obliquely upward and obliquely upward from the upper end of the second main body guide G32. The fourth main body guide G34 extends obliquely upward and obliquely upward from the upper end of the third main body guide G33 at a steeper angle than the third main body guide G33. Specifically, the angle of the fourth main body guide G34 with respect to the horizontal direction is larger than the angle of the third main body guide G33 with respect to the horizontal direction.

  The first pressing member P1 and the second pressing member P2 are members for pressing the drum unit 40 toward the positioning portion SP. The first pressing member P1 includes a lock member P11 and a spring P12.

  The lock member P11 is disposed at a position shifted in the left-right direction with respect to the positioning portion SP, and is provided in the main body housing 10 so as to be rotatable. The lock member P11 is rotatable between a first position (the position in FIG. 7) that closes the opening of the positioning portion SP and a second position (the position in FIG. 8) that opens the opening of the positioning portion SP. Yes. The lock member P11 is located at the first position when the support member 90 is located at the exposure position, and is located at the second position when the support member 90 is located at the separation position.

  Here, “closing the opening of the positioning portion SP” means that the opening of the lock member P11 and the positioning portion SP overlaps when viewed from the rotation axis direction of the photosensitive drum 41. Further, “opening the opening of the positioning portion SP” means that the opening of the lock member P11 and the positioning portion SP is shifted as seen from the rotation axis direction of the photosensitive drum 41.

  The lock member P11 includes a shaft portion P111, an arm portion P112, and a claw portion P113. The shaft portion P111 is a portion that becomes a rotation center of the lock member P11 and is supported by the main body housing 10 so as to be rotatable. The shaft portion P111 is disposed on the rear side of the positioning portion SP.

  The arm portion P112 extends obliquely upward and forward from the shaft portion P111 when the support member 90 is located at the exposure position. When the support member 90 is located at the exposure position, the claw portion P113 protrudes downward from the front end portion of the arm portion P112.

  The nail | claw part P113 has the contact surface F2 which contacts the reference axis A1 located in positioning part SP. The contact surface F2 is a surface for transmitting the pressing force FP1 of the first pressing member P1 to the reference axis A1. The contact surface F2 is formed at an angle such that the longitudinal component of the pressing force FP1 of the first pressing member P1 is greater than the vertical component. That is, in the pressing force FP1 of the first pressing member P1, the component in the predetermined direction is larger than the component in the orthogonal direction orthogonal to the predetermined direction and the rotation axis direction of the photosensitive drum 41.

  The spring P12 is a compression coil spring and is provided on the support member 90. Specifically, one end of the spring P12 is rotatably connected to the extending portion 95 of the support member 90. Further, the other end of the spring P12 is rotatably connected to the distal end portion of the arm portion P112. That is, the other end of the spring P12 is connected to the lock member P11.

  When the first pressing member P1 is configured as described above, the first pressing member P1 is pressed by the support member 90 when the support member 90 is rotated from the separated position to the exposure position, so that the first pressing member P1 is pressed. The member P1 presses the drum unit 40. Specifically, when the support member 90 is rotated from the separated position to the exposure position, the support member 90 presses the lock member P11 via the spring P12, so that the lock member P11 presses the reference axis A1 against the positioning portion SP. It is supposed to be.

  Further, as shown in FIG. 10, the first pressing member P <b> 1 contacts the drum unit 40 before the exposure head 50 and the developing cartridge 60 when the support member 90 is moved from the separated position to the exposure position. It is configured. Specifically, in the process of moving the support member 90 from the separation position to the exposure position, the protrusion 51 of the exposure head 50 is before the contact with the notch PP of the drum unit 40 and the first convex portion C1 of the developing cartridge 60 is The lock member P11 comes into contact with the reference axis A1 of the drum unit 40 before coming into contact with the first guide G21 of the drum unit 40.

  Returning to FIG. 7, the second pressing member P <b> 2 includes a moving member P <b> 21 that can move in the front-rear direction and a spring P <b> 22 that biases the moving member P <b> 21 backward. The moving member P21 is supported by the main body housing 10 so as to be movable in the front-rear direction. The moving member P21 has a main body part P211 and a support shaft P212.

  The main body P211 is pressed by the pressed surface A3 that presses the pressed portion A2 supported by the first main body guide G31 diagonally forward and downward, and the pressed portion A2 in the process of mounting the drum unit 40 to the main body housing 10. And a pressed surface F4 to be pressed. The rear end of the pressing surface F3 is connected to the rear end of the pressed surface F4. The pressing surface F3 extends obliquely downward and forward from the rear end of the pressed surface F4. The pressed surface F4 extends obliquely upward and forward from the rear end of the pressing surface F3.

  The pressing surface F3 is a surface for transmitting the pressing force FP2 of the second pressing member P2 to the pressed part A2. The pressing surface F3 is formed at an angle such that the longitudinal component of the pressing force FP2 of the second pressing member P2 is greater than the vertical component. That is, the pressing force FP2 of the second pressing member P2 has a component in a predetermined direction larger than the frictional force generated between the reference axis A1 and the first main body guide G31.

  The pressed surface F4 is a cam surface that converts a downward force applied from the pressed portion A2 into a forward force. Thus, in the process of mounting the drum unit 40 to the main body housing 10, when the pressed portion A2 presses the pressed surface F4 downward, the moving member P21 moves forward against the urging force of the spring P22. It is like that.

  As shown in FIG. 8, in a state where the drum unit 40 is removed from the main body housing 10, the pressed surface F4 is disposed at a position along the guide surface of the third main body guide G33. Specifically, the pressed surface F4 is formed at an angle such that the upper portion of the main body portion P211 does not protrude upward from the guide surface of the third main body guide G33.

  Returning to FIG. 7, the support shaft P212 is a shaft that supports the spring P22, and extends forward from the front surface of the main body P211. The support shaft P212 is disposed so as to penetrate the inside of the spring P22 that is a compression coil spring.

  The spring P22 is disposed between the main body portion P211 of the moving member P21 and the rotating member R. One end of the spring P22 is in contact with the main body P211 and the other end is in contact with the rotating member R.

  The rotating member R is a long plate-like member extending in the vertical direction, and is disposed adjacent to the support shaft P212 of the moving member P21 in the left-right direction. The rotation member R is supported by the main body housing 10 so that the central portion in the longitudinal direction can rotate. The lower end portion of the rotating member R is in contact with the spring P22. The upper end portion of the rotating member R can come into contact with a cam CM provided on the top cover 11.

  Specifically, when the top cover 11 is opened, the rotating member R is in a posture along the vertical direction as indicated by a two-dot chain line in the figure. More specifically, when the top cover 11 is opened, the lower end portion of the rotating member R is biased forward by the spring P22, but the movement is restricted by the stopper ST provided in the main body housing 10. Thus, the rotating member R is maintained in a posture along the vertical direction.

  A protrusion R1 that can come into contact with the cam CM is formed on the upper end of the rotating member R. The cam CM includes a cam surface CM1 that presses the protrusion R1 forward, and an engagement groove CM2 that can be engaged with the protrusion R1.

  By thus configuring the rotating member R and the cam CM, when the top cover 11 is closed, the cam CM of the top cover 11 comes into contact with the rotating member R and the rotating member R rotates counterclockwise in the drawing. By rotating, the rotating member R presses the second pressing member P2 toward the drum unit 40 along the front-rear direction. Further, the projection R1 is engaged with the engagement groove CM2, so that the top cover 11 is kept closed.

Next, the effect of the structure for positioning the drum unit 40 to the main body housing 10 will be described.
As shown in FIG. 8, when the drum unit 40 is mounted, the top cover 11 is opened and the support member 90 is disposed at the separated position. In the state where the support member 90 is disposed at the separated position, the lock member P11 coupled to the support member 90 via the spring P12 is located at the second position where the opening of the positioning portion SP is opened. The SP can be easily visually recognized.

  Next, the user moves the reference axis A1 toward the positioning portion SP while keeping the rear end of the drum unit 40 lower than the front end. At this time, the weight of the drum unit 40 can be reduced by placing the pressed portion A2 of the drum unit 40 on the fourth main body guide G34 or the third main body guide G33. can do.

  Thereafter, when the user slides the pressed portion A2 rearward and obliquely downward on the third body guide G33, the pressed portion A2 is moved from the third body guide G33 to the moving member P21 as shown in FIG. It is delivered to the pressed surface F4. Thereby, the load of the drum unit 40 is transmitted to the pressed surface F4, and the pressed surface F4 is pressed downward.

  When the pressed surface F4 is pressed downward, the moving member P21 gradually moves forward and the pressed portion A2 gradually moves downward. At this time, the spring P22 contracts due to the forward movement of the moving member P21, and the urging force is stored.

  When the pressed portion A2 comes into contact with the first main body guide G31, the pressed portion A2 comes into contact with the pressing surface F3 of the moving member P21, and is pressed obliquely downward in the front by the pressing surface F3. At this time, since the pressing force FP2 by the pressing surface F3 has a component in the front-rear direction larger than the component in the vertical direction, the drum unit 40 can be moved against the frictional force of each photosensitive drum 41 and the conveyor belt 73. The reference axis A1 can be pressed well against the positioning part SP.

  Thereafter, as shown in FIG. 10, when the support member 90 is rotated from the separated position toward the exposure position, the lock member P11 connected to the support member 90 via the spring P12 is moved from the second position to the first position. Rotate towards position. Then, in the process of rotating the support member 90 from the separation position toward the exposure position, the lock member P11 has the reference axis of the drum unit 40 before the exposure head 50 and the developing cartridge 60 contact the drum unit 40. Contact A1.

  As a result, the lock member P11 contacts the reference axis A1 of the drum unit 40 and presses the reference axis A1 before the frictional force generated by the exposure head 50 and the developing cartridge 60 coming into contact with the drum unit 40 is generated. 40 can be accurately positioned.

  When the support member 90 is rotated to the exposure position, the spring P12 is compressed between the support member 90 and the lock member P11, and the urging force of the spring P12 is stored. The biasing force of the spring P12 and the force applied by the user to the support member 90 are transmitted to the reference axis A1 via the contact surface F2 (see FIG. 7) of the lock member P11. At this time, the pressing force FP1 applied to the reference axis A1 from the contact surface F2 has a larger component in the front-rear direction than the component in the vertical direction, so the drum unit 40 is moved against the frictional force between the photosensitive drums 41 and the conveyor belt 73. And the reference axis A1 can be favorably pressed by the positioning portion SP.

  In other words, the drum unit 40 is positioned against the frictional force of the transport belt 73 by the force applied to the support member 90 when the support member 90 is moved from the separation position to the exposure position and the pressing force of the first pressing member P1. Since it can be pressed against the SP, the drum unit 40 can be accurately positioned with respect to the main body housing 10. At the exposure position, the support member 90 is locked to the main body housing 10 by a lock mechanism (not shown).

  After the support member 90 is rotated to the exposure position, as shown in FIG. 7, when the top cover 11 is closed, the cam CM presses the protrusion R1 of the rotation member R, so that the rotation member R is shown counterclockwise. Rotate around. Accordingly, the spring P22 is further compressed between the lower end portion of the rotating member R and the moving member P21, and the pressing force FP2 is further increased, so that the reference axis A1 can be strongly pressed by the positioning portion SP. .

As described above, according to the present embodiment, the following effects can be obtained in addition to the effects described above.
Since the first pressing member P1 and the second pressing member P2 can press the drum unit 40 against the positioning portion SP against the frictional force of the transport belt 73, the drum unit 40 is accurately positioned with respect to the main body housing 10. be able to. Further, for example, the force of the first pressing member P1 can be reduced as compared with the structure in which the drum unit 40 is pressed only by the first pressing member P1, so that the support member 90 is operated when the support member 90 is set at the exposure position. The reaction force from the 1st press member P1 added to the user who does can be made small.

  When the top cover 11 is closed, the rotating member R is rotated by the top cover 11 coming into contact with the rotating member R, so that the rotating member R presses the second pressing member P2 toward the drum unit 40. The force for closing the top cover 11 can be used as a force for positioning the drum unit 40.

  Further, when the top cover 11 is opened, the cam CM is detached from the rotating member R, so that the rotating member R returns to the original position by the urging force of the spring P22, and the urging force of the spring P22 is weakened. Therefore, when the top cover 11 is open, the pressing force applied to the drum unit 40 from the second pressing member P2 is weakened. Therefore, a small force is required when attaching and detaching the drum unit 40, and the attachment and detachment work can be easily performed. Can do.

  Since the lock member P11 is connected to the spring P12 provided on the support member 90, when the support member 90 is moved from the exposure position to the separated position, the lock member P11 connected to the spring P12 rotates to be the reference. Since it remove | deviates from axis | shaft A1, the user's effort which removes lock member P11 can be saved, and operativity can be improved.

  When the support member 90 is located at the separated position, the lock member P11 is located at the second position where the opening of the positioning part SP is opened. It becomes easy and operability can be improved.

  Since the first pressing member P1 and the second pressing member P2 are provided one each on the one side and the other side in the left-right direction with respect to the drum unit 40, the first pressing member P1 is disposed on both sides in the left-right direction. It can be pressed with a good balance by the member P1 or the like.

  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 said embodiment, although the structure provided with the member (locking member P11 or moving member P21) and spring P12, P22 which rotated or moved as a press member was illustrated, this invention is not limited to this. For example, the pressing member may be composed only of a spring. The spring may be a leaf spring, a torsion spring, or the like.

  In the said embodiment, although the locking member P11 and the spring P12 were connected, this invention is not limited to this, The locking member and the spring do not need to be connected.

  In the above-described embodiment, the conveyance belt 73 that conveys the paper P to and from the photosensitive drum 41 is illustrated, but the present invention is not limited to this. For example, the belt is an intermediate in which a developer image is transferred from the photosensitive member. A transfer belt may also be used.

  In the above embodiment, the top cover 11 is exemplified as the cover. However, the present invention is not limited to this. For example, the cover may be a front cover that opens and closes an opening on the front side of the main body housing.

  In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

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

DESCRIPTION OF SYMBOLS 1 Color printer 10 Main body housing | casing 40 Drum unit 41 Photosensitive drum 50 Exposure head 60 Developing cartridge 73 Conveying belt 90 Support member P1 1st press member SP Positioning part

Claims (9)

A drum unit having a plurality of photosensitive drums arranged in a predetermined direction;
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;
A belt in contact with the plurality of photosensitive drums;
A main body housing having a positioning portion for positioning the drum unit in the predetermined direction;
A first pressing member that presses the drum unit against the positioning portion;
When the support member is rotated from the separation position to the exposure position, the first pressing member is pressed by the support member, so that the first pressing member presses the drum unit,
The image forming apparatus according to claim 1, wherein the pressing force of the first pressing member is such that a component in the predetermined direction is larger than a component in an orthogonal direction orthogonal to the predetermined direction and a rotation axis direction of the photosensitive drum. The main body housing includes a second pressing member that presses the drum unit against the positioning unit, and a guide that extends toward the positioning unit,
The drum unit has a reference shaft guided by the guide and positioned by the positioning unit,
The image forming apparatus according to claim 1, wherein the pressing force of the second pressing member is such that a component in the predetermined direction is larger than a frictional force generated between the reference shaft and the guide. A cover for opening and closing an opening formed in the main body housing;
A pivot member that is pivotally supported by the body housing and is capable of contacting the cover and the second pressing member;
When the cover is closed, the rotating member is rotated by the cover being in contact with the rotating member, so that the rotating member presses the second pressing member toward the drum unit. The image forming apparatus according to claim 2.   The image forming apparatus according to claim 3, wherein the rotating member presses the second pressing member along the predetermined direction.   The said 1st press member contacts the said drum unit ahead of the said exposure head and the said developing cartridge when moving the said supporting member from the said separation position to the said exposure position from Claim 2 characterized by the above-mentioned. The image forming apparatus according to claim 4. The first pressing member includes a spring provided on the support member, and a lock member provided rotatably on the main body housing.
When the support member is rotated from the separation position to the exposure position, the support member presses the lock member via the spring, so that the lock member presses the reference shaft to the positioning portion. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 6, wherein the lock member is connected to the spring. The positioning portion is a recess,
The lock member is located at a first position that closes the opening of the positioning portion when the support member is located at the exposure position, and the opening of the positioning portion when the support member is located at the separation position. The image forming apparatus according to claim 7, wherein the image forming apparatus is located at a second position where the lens is opened.   The said 1st press member and the said 2nd press member are provided one each on the one side and the other side of the said rotating shaft direction with respect to the said drum unit, The Claim 2 to Claim 8 characterized by the above-mentioned. The image forming apparatus according to claim 1.

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