JP2005208075A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which a development unit is pressed against a latent image carrier, thereby correctly positioning a developer carrier, and which securely prevents an operator from inadvertently neglecting to attach the development unit by using a simple structure. <P>SOLUTION: A pressing mechanism that presses the bottom face of the development unit freely detachably attached to the image forming apparatus, thereby bringing the developing roller of the development unit into firm contact with a photoreceptor drum, comprises: a pressing plate 85; a cam member 89 which pushes up the pressing plate 85; an actuation rotary shaft 87 in which the cam member 89 is fixed; and an operation part 84 which rotates the actuation rotary shaft 87. The cam member 89 has a coil spring 107 and is always pressed in the direction of a standby position. In the case where the development unit 22 is not attached, the operation part 84 is always kept in a standby position by the pressing force of the coil spring 107. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus in which an image forming apparatus such as a copying machine, a printer, or a facsimile machine is detachably mounted with a developing unit used for developing a developer by attaching a developer to an electrostatic latent image.

  In an image forming apparatus, when an image is formed by attaching a developer (toner) to a latent image carrier on which an electrostatic latent image is formed, the developer decreases as the developer is used for image formation. It is necessary to replenish from time to time. For this reason, the developer is detachable from the image forming apparatus, and the developer is removed from the image forming apparatus main body and the developer is replenished or replaced as necessary. However, if the developing device is not accurately positioned on the latent image carrier, the developer is not uniformly supplied to the latent image carrier, causing problems such as unevenness in image formation.

In order to cope with such a problem, for example, in Patent Document 1, an elastic member is provided on the inner surface of the cartridge cover, and when the cartridge cover is mounted, the developing means is urged toward the photosensitive drum by the elastic member so The point to be positioned is described. Further, in Patent Document 2, a shaft fitting portion for fitting the shaft of the image carrier drum of the image forming unit on the support side plate and a pin fitting portion for fitting the engaging pin protruding from the unit frame are provided. It is described that the image carrier drum and the developing device can be mounted so that the positions thereof are always constant. Patent Document 3 describes that the developing unit is positioned at the operating position by pressing the bottom surface of the developing housing with a cam mechanism.
Japanese Patent Laid-Open No. 5-281798 JP 7-311500 A JP 2002-174952 A

  In the above prior art documents, a configuration for positioning and holding the developing device at a correct position when the developing device is mounted is described, but an image forming apparatus configured to detachably mount the developing device is described. In such a case, in addition to such positioning, a trouble that forgets to attach the developing device and operates the apparatus tends to occur. In order to prevent forgetting to attach the developing device, a sensor for detecting whether or not the developing device is attached may be provided to control the start of operation of the apparatus based on a detection signal from the sensor. Such parts and control processing are necessary, which increases the cost.

  Accordingly, the present invention provides an image forming apparatus capable of accurately positioning a developer carrying member by pressing a developing device against a latent image carrying member and reliably preventing forgetting to attach the developing device with a simple configuration. It is intended.

  An image forming apparatus according to the present invention includes a latent image carrier on which an electrostatic latent image is formed, a main body frame that pivotally supports the latent image carrier, and a developer carrier that supplies developer to the latent image carrier. A developer unit replenished with developer to the body and the developer carrying body, and a detachably mounted in the main body frame; a pressing body slidably provided on the main body frame; And an urging means for urging the developing device to be in a position to release the pressure against the pressing body. It is characterized by. Furthermore, a manual operation unit that is provided in the operating means and is set to an operating position where the operating means is in a pressed state and a standby position where the operating means is in a pressed release state, and opens and closes when the developer is attached / detached A main body cover, and a restriction projection provided on the main body cover so as to protrude to the standby position side of the manual operation unit set to the operating position when the main body cover is closed. Features.

  By having the configuration as described above, the actuating means is urged by the urging means so as to be in a position where the pressing body is released from the pressing body. Therefore, the operating means is not positioned to press the pressing body, and the operator can easily recognize that the developing device is not mounted. Accordingly, the operating means is prevented from being positioned at the position where the pressing member is pressed even though the developing device is not mounted, and forgetting to mount the developing device can be reliably prevented. In addition, when the operator installs the developing device, the operating means is always in a position to release the pressure against the pressing body, so that the mounting operation of the developing device can be easily performed.

  Further, a manual operation unit that is provided in the operating means and is set to an operating position where the operating means is in a pressed state and a standby position where the operating means is in a pressed release state; And a regulating projection provided on the main body cover so as to protrude toward the standby position side of the manual operation unit set to the operating position when the main body cover is closed, so that the developing device is not mounted. Then, the manual operation unit is always set at the standby position, and when the main body cover is closed in a state where the manual operation unit is set at the standby position, the manual operation unit collides with the regulation protrusion and closes the main body cover. I can't do that. Accordingly, the main body cover cannot be closed unless the developing device is attached, and the operator can reliably recognize that the forgetting to attach the developing device from the closing operation of the main body cover.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a schematic cross-sectional view of the entire image forming apparatus according to the present invention. A document reading unit 2 is arranged at the upper part of the image forming apparatus 1, and a paper feeding unit 3 and a recording unit 4 are arranged at the lower part from the bottom.

  In the document reading unit 2, the document placed on the document tray 11 provided on the document cover 10 is conveyed to the reading position by the document conveying device 12 and is discharged to the document discharge tray 13. At the reading position, a scanning device 16 equipped with a reading device 15 for optically reading a document is arranged so as to face the document. When reading a book or the like, the document cover 10 is rotated upward to place a read portion of the book or the like on the flat bed platen 14, and the scanning device 16 is moved as shown by an arrow to perform a reading operation. Is called. The above-described configuration is the same as that of a conventional document reading apparatus called a so-called ADF or flat bed type.

  In the paper feed unit 3, a paper feed cassette 17 is disposed, and a plurality of sheets of a predetermined size are stacked on the flapper 18. A pickup roller 19 is disposed at the right end of the paper feed cassette 17. The flapper 18 is urged upward by a spring member (not shown) so that the upper surface of the stacked paper comes into pressure contact with the pickup roller 19. When the pickup roller 19 is rotationally driven in this state, the sheets are fed one by one to the sheet conveyance path by the frictional force.

  The fed paper is first conveyed to the recording unit 4 by the feed roller 20 and the press roller 21. In the recording unit 4, a developer 22, a paper dust removing roller 23, a corona charger 24, a photosensitive drum 25, a transfer corotron wire 26, an exposure head 27 and a fixing roller 28 are used for recording on the conveyed paper. Is provided. The paper dust removing roller 23 is composed of a conductive sponge or the like, and supplements toner or paper dust attached to the surface of the photosensitive drum 25 after transfer. The corona charger 24 uniformly charges the surface of the photosensitive drum 25 by the discharge from the corotron. An electrostatic latent image is formed by exposing the photosensitive drum 23 uniformly charged by the paper dust removing roller 23 and the corona charger 24 according to the image recording signal by the exposure head 25. Then, as will be described later, the toner in the developing device 22 is transferred to the electrostatic latent image formed on the photosensitive drum 25 to visualize the electrostatic latent image. The transfer roller 26 is installed at a position facing the photosensitive drum 25 with the paper interposed therebetween, and a toner image formed on the surface of the photosensitive drum 25 is transferred to the paper when a predetermined voltage is applied. The transferred toner image is sandwiched between the fixing roller 28 and the press roller 29 and heated and pressed to be fixed on the paper. The fixed paper is sandwiched between the paper discharge roller 30 and the press roller 31 and is carried out to the paper discharge tray 32.

  In FIG. 1, a sheet conveyance path is indicated by a one-dot chain line from the sheet feeding unit 3 to the sheet discharge tray 32. A conveyance roller and a paper guide arranged along the paper conveyance path constitute a paper conveyance unit.

  A reversal conveyance unit 40 is detachably mounted on a side surface of the apparatus main body, and a paper carry-out port 41 and a paper carry-in port 42 are formed on the mounting side surface. In the transport unit 40, two pairs of transport rollers, a feed roller 43 and a press roller 44, and a feed roller 45 and a press roller 46, are arranged up and down. Then, as shown by a two-dot chain line in FIG. 1, the reverse conveyance path branches off from the sheet conveyance path between the paper discharge roller 30 and the fixing roller 28, and the two pairs of conveyance rollers 43 and 44, 45 and 46 are separated. It is formed so as to pass through and to join the paper conveyance path between the roller pairs 20 and 21 and the pickup roller 19.

  When recording on both sides of the sheet, the sheet is conveyed to the sheet conveyance path indicated by the one-dot chain line in FIG. 1 and recorded on one side, and then the sheet is carried out to the sheet discharge tray 32 by the discharge roller 30. The carry-out operation is temporarily stopped in a state where the rear end portion of the paper is sandwiched between the paper discharge roller 30 and the press roller 31. Then, the paper discharge roller 30 is driven to rotate reversely, the paper is carried into the reverse conveyance path from the rear end, and is nipped by the feed roller 43 and the press roller 44 to be conveyed in the reverse conveyance path. Next, the paper is nipped by the feed roller 45 and the press roller 46 and further conveyed, and the paper is brought into contact between the roller pair 20 and 21. When the sheet is conveyed to the sheet conveyance path in this state, the other surface is recorded to face the photosensitive drum 25, and recording is performed on both sides of the sheet.

  FIG. 2 shows an enlarged cross-sectional view of the recording unit 3 in FIG. FIG. 3 shows an enlarged sectional view of the developing device 22. As described above, the developing device 22, the paper dust removing roller 23, the corona charger 24, and the transfer roller 26 are disposed around the photosensitive drum 25, and between the corona charger 24 and the developer 22. Laser light is emitted from the exposure head 27 to the surface of the photosensitive drum 25 in accordance with the image recording signal.

  The developing device 22 is configured by sealing the upper portion of the container body 50 with a lid 51. Three toner chambers 52, 53, and 54 are formed inside the container body 50 as toner replenishing chambers, and a supply chamber 57 having a developing roller 55 and a supply roller 56 at the side end on the photosensitive drum 25 side. Is formed. The first toner chamber 52 and the supply chamber 57 are partitioned by a partition plate 58 extending from the lower surface of the lid 51, and a supply opening 59 is formed in the partition plate 58.

  As shown in FIG. 3, the three toner chambers 52, 53, and 54 are configured to be arranged in parallel in the horizontal direction with the developing unit 22 mounted on the image forming apparatus 1. Paddles 60, 61, and 62 are provided as stirring transfer means in a substantially central portion of the chamber. In FIG. 2, assuming that the vertical direction of the paper surface is the front-rear direction of the developing device 22, the rotation shaft of each paddle is provided so that both ends in the front-rear direction are supported by the front-rear frame of the container body 50 and follow the front-rear direction It has been. A blade 63 made of a flexible resin film is attached to the tip of the paddle 60 so as to follow the rotational direction. Similarly, a blade 64 is attached to the paddle 61, and a blade 65 is attached to the paddle 62. These blades 63 to 65 use a common member. The bottom surface of the container main body 50 is formed with sliding surface portions 66, 67, and 68 that are curved outward in a circular arc shape along the trajectory of the rotational movement of the blade attached to each paddle.

  The toner supplied to each of the toner chambers 52 to 54 is stored in the sliding surface portions 66, 67, and 68. When the paddles 60, 61, 62 rotate, the blades 63, 64, 65 rotate so as to slide on the sliding surface portions 66, 67, 68, respectively. The toner is picked up by the sliding motion of each blade, and the toner is agitated in each toner chamber to prevent deterioration due to toner aggregation. Further, as shown in FIG. 2, the blades 63, 64, 65 rotate counterclockwise, whereby the toner in the third toner chamber 54 is transferred to the second toner chamber 53, and the toner in the second toner chamber 53 Is transferred to the first toner chamber 52. The toner in the first toner chamber 52 is supplied to the supply chamber 57 from the supply opening 59 of the partition plate 58. At that time, the replenished toner is agitated by the paddle 60 in the first toner chamber 52 and preliminarily charged. The supply opening 59 has a slit shape in the front-rear direction, and the amount of toner supplied from the first toner chamber 52 to the supply chamber 57 can be adjusted by adjusting the opening width and the opening position. .

  The toner replenished in the supply chamber 57 is rubbed and charged by slidingly contacting the developing roller 55 while the supply roller 56 rotates, and is carried on the surface of the developing roller 55. On the developing roller 55, a developing blade 69 that regulates the layer thickness of the supplied toner is disposed close to the surface of the developing roller 55. As the developing roller 55 and the photosensitive drum 25 are in sliding contact with each other while rotating, a toner layer regulated to a constant layer thickness by the developing blade 69 adheres to the electrostatic latent image formed on the surface of the photosensitive drum 25. And developed.

  As will be described later, the developing device 22 is detachably attached to the image forming apparatus 1 in the front-rear direction. In FIG. 2, when the front side of the paper surface in the vertical direction is the front surface portion of the developing unit 22 and the opposite side is the rear surface portion, when the developing device 22 is inserted into the image forming apparatus 1, It is inserted into the mounting space formed in 70 from the rear surface and mounted. After being inserted, the developing device 22 is set in a state in which the container main body 50 is pushed up from below by a pressing mechanism 71 provided on the main body frame 70 of the image forming apparatus 1 and the developing roller 55 is in contact with the photosensitive drum 25. The Further, the toner remaining amount detecting sensor 72 is raised in conjunction with the pressing operation of the pressing mechanism 71 and is set in the concave groove 73 made of a transparent member provided on the sliding surface portion 67.

  FIG. 4 shows a state in which the developing unit 22 is inserted into the main body frame 70 as seen from the front side, but the pressing mechanism 71 is orthogonal to the rotation center axes 74 and 75 of the photosensitive drum 25 and the developing roller 55. It presses in the direction of a parallel arrow along the straight line 76.

  A guide member 78 is fixed to the front frame 77 of the container body 50 so that the developing roller 55 is accurately set on the photosensitive drum 25 when pressed by the pressing mechanism 71. The guide member 78 has a flat plate shape and is fixed at a position near the photosensitive drum 25 of the front frame 77. A guide portion 79 extending toward the rotation center axis 74 of the photosensitive drum 25 is formed, and an elliptical guide hole 80 is formed in the guide portion 79 along the straight line 76. Yes. The width of the guide hole 80 is set to such an extent that the rotation center shaft 74 is fitted.

  On the other hand, as shown in FIG. 5, on the rear side of the developing device 22, a positioning long hole 82 is formed along the straight line 76 in the rear surface portion 81 of the main body frame 70. The width of the positioning slot 82 is set such that the rotation center shaft 75 of the developing roller 55 is fitted.

  FIG. 6 is a schematic view showing a state in which the developing roller 55 is in pressure contact with the photosensitive drum 25. The photosensitive drum 25 has a front end portion of the rotation center shaft 74 supported on the upper surface portion of the main body frame 70 and a rear end portion supported on the rear surface portion 81. When the developing device 22 is inserted, the end portion of the rotation center shaft 75 of the developing roller 55 protruding outward toward the rear surface side of the developing device 22 is guided to be inserted into the positioning slot 82. At the same time, the guide hole 80 of the guide member 79 fixed to the front side of the developing device 22 is guided so as to be fitted into the end of the rotation center shaft 74 of the photosensitive drum 25 protruding outward.

  Thus, the rotation center shaft 74 of the photosensitive drum 25 is set in the guide hole 80 and the rotation center shaft 75 of the developing roller 55 is set in the positioning slot 82, and the pressing mechanism 71 is operated to push up the developing device 22. At that time, since the guide hole 80 and the positioning long hole 82 are formed in a hole shape along the straight line 76, the developing device 22 moves along the straight line 76, and the rotation center shaft 75 of the developing roller 55 is The position is set to be parallel to the rotation center axis 74 of the photosensitive drum 25. Gap rollers 83 are fixed to the rotation center shaft 75 on both sides of the developing roller 55. The gap roller 83 is set to be slightly smaller than the diameter of the developing roller 55 in order to keep the distance between the surface of the photosensitive drum 25 and the rotation center shaft 75 of the developing roller 55 at a predetermined interval. The gap roller 83 is pressed against the surface of the photosensitive drum 25 by the pressing force of the pressing mechanism 71, so that the developing roller 55 can be brought into a uniform pressure contact state with the surface of the photosensitive drum 25.

  Further, when the photosensitive drum 25 and the developing roller 55 are driven to rotate, the developing roller 55 is dragged in the rotating direction of the photosensitive drum 25. However, as described above, the developing unit 22 has the guide hole 80 and positioning. Since the elongated holes 82 are set to such a width that the rotation center shafts 74 and 75 are fitted to each other, the elongated holes 82 are not restricted by the respective holes and deviated from the set positions.

  Next, the pressing mechanism 71 will be described. The pressing mechanism 71 is disposed near the photosensitive drum 25 on the bottom surface of the main body frame 70. 7 and 8 show perspective views of the pressing mechanism 71. FIG. FIG. 7 shows a state in which the operation unit 84 is manually rotated to the operating position, and the rectangular plate-shaped pressing plate 85 is raised and protrudes from the substrate 86. FIG. 8 shows the operation unit 84 manually counterclockwise. The state is shown in which the pressing plate 85 is lowered by being rotated to the standby position that has fallen around. In FIG. 7, the toner remaining amount detection sensor 72 is rotated to the set position in the replenishing chamber of the developing device 22 in accordance with the rotation operation of the operation unit 84 to the operation position. With the rotation operation, the toner remaining amount detection sensor 72 is rotated to the retracted position.

  FIG. 9 shows an exploded perspective view of the pressing mechanism 71. The operation portion 84 is fixed to the front end portion of the operation rotating shaft 87. The operating rotary shaft 87 is rotatably held by a bearing portion 88 that is provided below at a front end and a rear end of the substrate 86. A plate cam member 89 and a sensor cam member 90 are fixed to an intermediate portion of the operation rotating shaft 87. The pressing plate 85 extends in a belt shape in the front-rear direction, and four holding portions 91 that accommodate the action member 92 are formed. In the example shown in FIG. 9, the action member 92 is accommodated in each of the two holding portions 91 in the central portion, and the two holding portions 91 in both side portions are empty. Each holding portion 91 is formed in a prismatic shape, and a rectangular space for accommodating the action member 92 is formed inside. Each of the holding portions 91 is arranged two at the front and rear at a symmetrical position with respect to the center line in the vertical direction of the pressing plate 85. Ribs 93 are formed on the upper and lower end edges of the pressing plate 85, and vertical ribs 94 that connect the upper and lower ribs are formed at predetermined intervals to increase the strength of the pressing plate 85. Guide protrusions 95 are formed at both ends of the pressing plate 85 in the front-rear direction, and restriction protrusions 96 are provided below the protrusions 95. A cam receiving portion 97 projects in the horizontal direction at the center of the lower edge of the pressing plate 85.

  A notch 98 is formed on the side surface of the substrate 86 close to the photosensitive drum 25 corresponding to the mounting position of the pressing plate 85, and the holding plate 91 is further received by the pressing plate 85 in the notch 98. A holding receiving portion 99 is formed. In addition, on the front and back sides of the notch 98, a recess 100 for moving the guide projection 95 up and down is formed. The holding receiving portion 99 has a guide surface parallel to the straight line 76 shown in FIG. 4, and although not shown, the regulating projection 96 is moved up and down along the straight line 76 inside the bearing portion 88. Grooves are formed.

  When the pressing plate 85 is attached to the substrate 86, the restricting projection 96 is inserted into the groove, the guide projection 95 is fitted into the recess 100, and each holding portion 91 is fitted into the holding receiving portion 99. Like that. In the mounted state, the pressing plate 85 moves up and down along the straight line 76 by the groove into which the guide surface of the holding receiving portion 99 and the restricting projection portion 96 are inserted.

  On the other hand, on the side surface of the substrate 86 opposite to the photoconductive drum 25, a pair of shaft support portions 101 are attached to the central portion so that the toner remaining amount detection sensor 72 is rotatably attached. A pair of rotating shafts 103 project from the front and rear side surfaces of the attachment portion 102 provided in the toner remaining amount detection sensor 72, and the attachment portion 102 is inserted between the pair of shaft support portions 101 to rotate. The moving shaft 103 is fitted into the shaft support portion 101 and the toner remaining amount detection sensor 72 is attached.

  One engagement end of the plate coil spring 105 is engaged with the engagement hole portion 104 formed adjacent to the cam receiving portion 97 of the pressing plate 85, and the other engagement end is connected to the operation rotating shaft 87. Is engaged. The plate spring 105 urges the pressing plate 85 so as to always pull the pressing plate 85 toward the operation rotating shaft 87. When the pressing plate 85 is urged by the plate spring 105, the pressing plate 85 moves downward, and the bottom surface of the restricting protrusion 96 is held in contact with the operation rotating shaft 87.

  An engagement protrusion 106 is provided on the side surface of the plate cam member 89, and one engagement end of the cam coil spring 107 is engaged with the engagement protrusion 106, and the other engagement end is connected to the shaft support portion 101. It is engaged with an engaging hole 108 formed in the substrate 86 adjacently. The cam coil spring 107 constantly urges the plate cam member 89 to rotate counterclockwise as viewed from the direction of the arrow 300 in FIG. Therefore, when the plate cam member 89 is rotated counterclockwise by the cam coil spring 107, the operation rotating shaft 87 is also rotated, and the operation portion 84 is rotated to the standby position.

  A compression spring 109 is attached to the inside of the attachment portion 102 of the toner remaining amount detection sensor 72 between the lower surface of the substrate 86. Since the compression spring 109 acts to press the pressure contact portion 110 formed at a position closer to the photosensitive drum 25 than the rotation shaft 103, the toner remaining amount detection sensor 72 is attached so as to always rotate upward. It is energized.

  FIG. 10 is a side view of the pressing mechanism 71 in the standby state shown in FIG. 8 as viewed from the opposite side of the photosensitive drum 25. 11A to 11C show cross-sectional views taken along lines AA, BB, and CC in FIG. FIG. 12 shows a state where the plate cam member 89 is biased by the cam coil spring 107. As shown in FIG. 10, the pressing plate 85 is urged downward by the plate coil spring 105 and is in a state where the bottom surface of the restricting protrusion 96 is in contact with the operation rotating shaft 87. As shown in FIG. 12, the plate cam member 89 is urged to rotate counterclockwise by the cam coil spring 107, so that the rotation shaft 87 and the sensor cam member 90 are similarly counterclockwise. It is biased to rotate around.

  FIG. 13 is a side view of the pressing mechanism in the operating state shown in FIG. 7 as viewed from the opposite side of the photosensitive drum 25. 14A to 14C are cross-sectional views taken along lines AA, BB, and CC in FIG.

  The action member 92 is slidably accommodated inside the holding portion 91 and is urged to move upward by a coil spring provided between the bottom surface of the action member 92 and the holding portion 91. A screw inserted through the bottom surface of the holding portion 91 is screwed into the bottom surface of the action member 92 to restrict the upward movement of the action member 92.

  Therefore, as shown in FIG. 11A, since the head of the screw 111 engages with the bottom surface of the holding portion 91, the action member 92 is held in the holding portion 91 against the urging force of the coil spring. . As shown in FIG. 14A, in a state where the action member 92 presses the bottom surface of the developing device 22, the action member 92 is pushed into the holding portion 91, and the head portion of the screw 111 protrudes downward. Thus, the bottom surface of the developing device 22 is pressed and held by the repulsive force of the coil spring.

  The plate cam member 168 has two inclined surfaces 113 and 114 formed so as to spread from the top portion 112 toward the operation rotating shaft 87 as shown in the cross-sectional shape of FIG. The inclined surface 113 on the side opposite to the photosensitive drum 25 has a shape bulging outward, and the inclined surface 114 on the side close to the photosensitive drum 25 has a substantially flat shape. The plate cam member 89 is urged to rotate counterclockwise by the cam coil spring 107. In the standby state of the pressing mechanism 71, as shown in FIG. With respect to the photosensitive drum 25, the pressing plate 85 is urged downward by the plate coil spring 105, and the cam receiving portion 97 is brought into contact with the inclined surface 114 and stopped.

  When the operation unit 84 is manually rotated clockwise, the operating rotary shaft 87 is also rotated in the same manner, so that the plate cam member 89 fixed to the operating rotary shaft 87 rotates clockwise. The plate cam member 89 rotates from the state of FIG. 11B to the state of FIG. 14B, and the top portion 112 of the plate cam member 89 pushes up the cam receiving portion 97 as shown in FIG. 14B. It rotates as follows. Therefore, the pressing plate 85 moves upward. At that time, the pressing plate 85 moves along the guide surface 115 formed on the main body frame 70. The guide surface 115 is formed along the straight line 76 described above. When the top 112 is pushed up while sliding the cam receiving portion 97 by the rotation of the plate cam member 89 and is rotated to the photosensitive drum 25 side of the pressing plate 85, as shown in FIG. It enters between the pressing plate 85 and the guide surface 115 from the end edge of the receiving portion 97.

  When the developing device 22 is mounted and the load of the developing device 22 is applied to the action member 92, the plate cam member 89 is in a state where the top portion 112 enters between the end edge of the cam receiving portion 97 and the guide surface 115. Even when the cam coil spring 107 is urged to rotate counterclockwise, the top 112 is held in contact with the edge of the cam receiving portion 97 to support the pressing plate 85. However, even if the plate cam member 89 is rotated to the state shown in FIG. 14B when the developing device 22 is not attached, the top 112 is pressed by the urging force of the cam coil spring 107. It acts to push up 85 and return to the standby state of FIG.

  Therefore, even if the operation unit 84 is rotated when the developing device 22 is not attached, the state automatically returns to the standby state of FIG. 8, so that the operator can easily confirm that the developing device 22 is not attached. Can be recognized. Therefore, it is possible to avoid troubles such as forgetting to attach the developing device 22 and starting driving the apparatus.

  Although not shown, the main body frame 70 is provided with a protrusion for a stopper that is held in the standby state of FIG. 8 when the operation portion 84 is rotated by the biasing force of the cam coil spring 107. When the device 22 is not attached, the standby state shown in FIG. 8 is always maintained.

  The sensor cam member 169 has two inclined surfaces 117 and 118 formed so as to spread from the top portion 116 toward the operation rotating shaft 87 as shown in the side surface shape of FIG. The inclined surface 117 on the side opposite to the photosensitive drum 25 has a shape bulging outward, and the inclined surface 118 on the side close to the photosensitive drum 25 has a substantially flat shape. In the standby state shown in FIG. 10, the top portion 116 is in contact with the sliding surface 119 formed on the lower surface of the mounting portion 102 of the toner remaining amount detection sensor 72. In this state, the attachment portion 102 is urged downward by the compression spring 109 and presses against the top portion 116. However, since the sensor cam member 90 is fixed to the operating rotary shaft 87 and the plate cam member 89 is stopped by contacting the cam receiving portion 97 by the cam coil spring 107 as described above, the sensor cam member is stopped. 90 is also in a stopped state. Accordingly, since the sensor unit 120 of the toner remaining amount detection sensor 72 is held in the retracted state, the sensor unit 1204 can be prevented from contacting the bottom surface of the developing unit 22 when the developing unit 22 is inserted.

  In the operation state shown in FIG. 14C, the sensor cam member 90 rotates clockwise, the top portion 116 moves away from the sliding surface 119, and the inclined surface 117 and the sliding surface 119 come into contact with each other. In this state, the attachment portion 102 moves downward, the toner remaining amount detection sensor 72 rotates clockwise, and the sensor portion 120 moves upward. As shown in FIG. 2, when the sensor unit 120 moves upward, the sensor unit 120 is set in a groove 73 provided on the bottom surface of the replenishing chamber of the developing device 22.

  FIG. 15 is a perspective view of the entire image forming apparatus 1 showing a state in which the main body cover 121 is opened. The main body cover 121 is pivotally supported by the apparatus main body at both ends of the lower end portion, and is opened so as to fall down on the front side. When the developing device 22 is attached / detached, the main body cover 121 is first opened, the attaching / detaching operation of the developing device 22 is performed, and then the main body cover 121 is closed.

  On the inner surface of the main body cover 121, a restriction projection 122 having a rectangular cross section and formed in a cylindrical shape protrudes. The restricting protrusion 122 has a height that protrudes into a passing region where the operation portion 84 moves from the standby position to the operating position in a state where the main body cover 121 is closed. Therefore, if the restricting protrusion 122 comes into contact with the operation portion 84 when the main body cover 121 is closed, the main body cover 121 cannot be closed.

  FIG. 16 is a view of the restriction projection 122 viewed from the front side when the main body cover 121 is closed. The operation unit 84 is configured to rotate from a standby position drawn with a dotted line to an operating position drawn with a solid line. As described above, when the developing device 22 is not attached, the operation portion 84 is always held in contact with the stopper projection 123 provided on the main body frame 70 at the standby position by the biasing force of the cam coil spring 107. Therefore, if the main body cover 121 is to be closed in a state where the developing device 22 is not attached, the restricting protrusion 122 will collide with the operation portion 84 and the main body cover 121 cannot be completely closed.

  As described above, since the main body cover 122 cannot be completely closed if the developing device 22 is not attached, the operator can easily recognize that the developing device 22 is not attached. Forgetting to attach 22 can be reliably prevented.

1 is a schematic sectional view of an entire image forming apparatus according to an embodiment of the present invention. It is an expanded sectional view regarding a recording part. It is an expanded sectional view regarding a developing device. It is the figure which looked at the inserted developing device from the front side. It is the figure which looked at the inserted developing device from the back side. It is explanatory drawing regarding the positioning state of a photoconductor drum and a developing roller. It is a perspective view of the operating state of a press mechanism. It is a perspective view of the standby state of a press mechanism. It is a disassembled perspective view of a press mechanism. It is a side view of the standby state of a press mechanism. It is AA, BB, and CC sectional drawing of FIG. It is a figure which shows the mounting state of the cam member for plates of FIG. 10, and the coil spring for cams. It is a side view of the operating state of a press mechanism. It is AA, BB, and CC sectional drawing of FIG. FIG. 2 is a perspective view of the entire image forming apparatus with a main body cover opened. It is a figure explaining the positional relationship of a control protrusion part and an operation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Document reading part 3 Paper feed part 4 Recording part
22 Developer
25 Photosensitive drum
50 Container body
51 lid
55 Developing roller
70 Body frame
71 Pressing mechanism
72 Toner level detection sensor

Claims (2)

  A latent image carrier on which an electrostatic latent image is formed, a main body frame that pivotally supports the latent image carrier, a developer carrier that supplies developer to the latent image carrier, and development on the developer carrier A developing device having a replenishing chamber for replenishing the agent and detachably mounted in the main body frame; a pressing body slidably provided on the main body frame; and the developing device by sliding the pressing body. And an urging means for urging the actuating means to be in a position to release the pressure against the pressing body. apparatus.   A manual operation unit which is provided in the operating unit and is set to an operating position where the operating unit is in a pressed state and a standby position where the operating unit is in a pressed release state, and is opened and closed when the developer is attached / detached. A main body cover, and a regulation protrusion provided on the main body cover so as to protrude toward the standby position side of the manual operation unit set to the operating position when the main body cover is closed. The image forming apparatus according to claim 1.

Images