JP2005338874A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus where an image carrier is rotatably assembled in a unit holder so as to constitute an image carrier unit, the image carrier unit is attachably/detachably attached to an image forming apparatus main body, and a laser beam is made incident from an opening part formed on the unit holder so that an electrostatic latent image is formed on the surface of the image carrier, wherein external light is prevented from entering from the opening part formed on the unit holder when the image carrier unit is taken out to the outside of the image forming apparatus. <P>SOLUTION: The image forming apparatus is provided with a shutter 84 for shutting the opening part 53 formed on the unit holder 40 when the image carrier unit 41 is drawn out to the outside of the image forming apparatus main body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes an image carrier on which an electrostatic latent image is formed, a charging device for charging the image carrier, an exposure device for exposing the charged surface to form an electrostatic latent image, and the electrostatic latent image. The present invention relates to an image forming apparatus including a developing device that visualizes an image as a toner image.

  An image forming apparatus of the above type configured as an electronic copying machine, a facsimile machine, a printer, or a multifunction machine having at least two of these functions is well known. In order to enhance the maintainability of such an image forming apparatus, it is advantageous to construct an image carrier unit by assembling the image carrier to a unit holder, and to attach the image carrier unit to the main body of the image forming apparatus so that it can be pulled out. In this way, the image carrier can be easily taken out of the image forming apparatus main body by pulling out the image carrier unit from the image forming apparatus main body during maintenance work such as maintenance inspection or replacement of the image carrier. Further, by storing the image carrier unit in the image forming apparatus main body, the image carrier can be easily set at a predetermined position in the image forming apparatus main body.

  When the image carrier is configured by assembling the image carrier to the unit holder as described above, an opening through which light emitted from the exposure apparatus passes is formed in the unit holder so that the image carrier can be exposed during the image forming operation. There is a need. However, when such an opening is formed, when the image carrier unit is pulled out from the inside of the image forming apparatus main body, external light may enter the unit holder through the opening and may deteriorate the image carrier. is there.

  An object of the present invention is to provide an image forming apparatus that eliminates the above-described drawbacks.

  To achieve the above object, according to the present invention, in the image forming apparatus of the type described at the beginning, the image carrier is assembled to a unit holder having an opening through which light emitted from the exposure device passes. The image carrier unit is detachably mounted on the image forming apparatus main body, and when the image carrier unit is pulled out from the image forming apparatus main body, an opening formed in the unit holder is formed. An image is provided that opens and closes to occupy an open position that occupies an open position that occupies an open position that occupies an open position that occupies a closed position and closes the image carrier unit at a predetermined position in the image forming apparatus main body. A forming apparatus is proposed (claim 1).

  At this time, it is advantageous to hold the image carrier unit and the developing device on a drawer that is supported so as to be drawable with respect to the main body of the image forming apparatus.

  3. The image forming apparatus according to claim 1, wherein when the image carrier unit is pulled out from the image forming apparatus main body, the shutter operates in a closed position that closes the opening according to the movement of the image carrier unit. It is advantageous if configured as described above (claim 3).

  Furthermore, in the image forming apparatus according to any one of claims 1 to 3, when the shutter is stored in a predetermined position in the main body of the image forming apparatus, the shutter opens with the movement. It is advantageous if it is configured to operate in an open position that opens the part.

  3. The image forming apparatus according to claim 1 or 2, wherein the urging means for urging the shutter to its closed position and the image carrier unit stored in a predetermined position in the image forming apparatus main body. It is advantageous to provide guide means for guiding the shutter so that the shutter operates in its open position against the action of the biasing means.

  Further, in the image forming apparatus according to any one of claims 1 to 5, it is advantageous that the shutter is provided in the image carrier unit (claim 6).

  According to the image forming apparatus of the first aspect, when the image carrier unit is pulled out, it is possible to prevent light from entering from an opening formed in the unit holder, thereby preventing the image carrier from deteriorating. Can do.

  According to the image forming apparatus of the second aspect, since the image carrier unit and the developing device are held by the drawer, the maintenance can be easily performed.

  According to the image forming apparatus of the third aspect, when the image carrier unit is pulled out of the image forming apparatus main body, the shutter is automatically closed, so that it is possible to prevent the shutter from being forgotten to be closed.

  According to the image forming apparatus of the fourth aspect, since the shutter is automatically opened when the image carrier unit is set in the image forming apparatus main body, it is possible to prevent forgetting to open the shutter.

  According to the image forming apparatus of the fifth aspect, forgetting to close the shutter and forgetting to open the shutter can be prevented with a simple configuration.

  According to the image forming apparatus of the sixth aspect, even when the image carrier unit is completely detached from the image forming apparatus main body, the opening can be reliably closed by the shutter.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic sectional view showing the internal structure of a color copying machine as an example of an image forming apparatus as viewed from the front side. When making a color copy with this color copying machine, a document (not shown) is placed on the contact glass 2 fixed on the upper part of the image forming apparatus main body 1 and is pressed by the pressure plate 3 to be shown in the drawing. Press no start switch. As a result, the reading optical system 4 operates to read the document image.

  On the other hand, an image carrier 5 is disposed inside the image forming apparatus main body 1, and an image carrier made of a drum-shaped photoconductor is used in the illustrated example. The image carrier 5 is rotationally driven in the counterclockwise direction in FIG. 1, and at this time, the surface of the image carrier is uniformly made to have a predetermined polarity by a discharge action of a charging charger 6 comprising a corona discharger as an example of a charging device. Is charged.

  A laser writing unit 7, which is an example of an exposure apparatus, is disposed above the image carrier 5, and from this writing unit 7, a laser beam L that is light-modulated according to image information read by the reading optical system 4. The laser beam L is emitted and irradiated onto the surface of the image carrier charged as described above, whereby a first electrostatic latent image is formed on the surface of the image carrier.

  Next to the image carrier 5, a rotating type developing device 8 which is an example of a developing device is disposed. The developing device 8 includes a black developing device 8BK, a cyan developing device 8C, a magenta developing device 8M, and a yellow developing device 8Y. have. Each developing unit has developing rollers 9BK, 9C, 9M, and 9Y. When the first electrostatic latent image passes through the developing device 8, the first developing unit, in this example, the black developing unit 8BK carries the image. The first electrostatic latent image is visualized as a black toner image by a black developer (not shown) that occupies the developing position facing the body 5 and is carried on the developing roller 9BK. In this way, a toner image is formed on the surface of the image carrier 5. As the developer, a two-component powder developer having a toner and a carrier is used, but a powdery one-component developer having no carrier can also be used.

  On the other hand, an intermediate transfer member 11 made of a flexible endless belt wound around a plurality of rollers 10 including a drive roller is placed on the surface of the image carrier, and this intermediate transfer member 11 is rotationally driven in the direction of the arrow. However, a part of the surface abuts on the surface of the image carrier 5, and the abutting portion moves in the same direction as the moving direction of the image carrier surface at the same linear velocity as that of the image carrier surface. A black toner image formed on the surface of the image carrier is transferred onto the surface of the intermediate transfer member 11 by the discharging action of the primary transfer device 12 including, for example, a corona discharger. A voltage may be applied to one roller 10 located in the vicinity of the image carrier 5, whereby the toner image on the surface of the image carrier may be transferred to the intermediate transfer body 11. In this case, the roller 10 is primary. Construct a transfer device. Thus, in this example, the intermediate transfer member 11 constitutes a transfer material to which the toner image on the surface of the image carrier is transferred.

  The transfer residual toner adhering to the surface of the image carrier after the toner image is transferred to the intermediate transfer body 11 is removed by the cleaning device 14, and then the surface of the image carrier is irradiated with light from the static eliminator comprising the static elimination lamp 15. Then, the absolute value of the surface potential is lowered to the reference value.

  In exactly the same manner as described above, the second electrostatic latent image is formed on the surface of the image carrier. At this time, by the rotation of the developing device 8, the second developing device, in this example, the cyan developing device 8C occupies the developing position facing the surface of the image carrier, and the cyan developer carried on the developing roller 9C causes the first developing device to The electrostatic latent image 2 is visualized as a cyan toner image. This toner image is also transferred onto the surface of the intermediate transfer member 11 in a superimposed state from above the previously transferred black toner image. The surface of the image carrier after the transfer of the toner image is cleaned by the cleaning device 14 and is subjected to the discharging operation by the discharging lamp 15 as in the previous operation.

  Further, in exactly the same manner as described above, the third and fourth electrostatic latent images sequentially formed on the surface of the image carrier are converted into magenta developing unit 8M of developing device 8 and developing rollers 9M, A magenta toner image and a yellow toner image are sequentially visualized as a magenta toner image and a yellow toner image by the magenta developer and the yellow developer carried on 9Y, and these are superimposed on the surface of the intermediate transfer body from above the toner image previously transferred. The images are transferred in order. In this manner, four color toner images are formed on the surface of the intermediate transfer member in a superimposed state.

  On the other hand, a secondary transfer device 18 made of, for example, a corona discharger is opposed to the intermediate transfer body 11, and a transfer sheet, which is an example of a final transfer material, is provided from the paper supply device 16 disposed below the secondary transfer device 18. P is fed in the direction of arrow A. The transfer paper P is fed between the secondary transfer device 18 and the intermediate transfer body 11 at a timing that aligns with the toner image on the intermediate transfer body 11 by the rotation of the registration roller pair 17. At this time, the superposed toner image on the surface of the intermediate transfer member is transferred to the surface of the transfer paper that moves while being in contact with the surface of the intermediate transfer member by the discharging action of the secondary transfer device 18.

  The transfer paper P onto which the toner image has been transferred is carried on the transport belt 19 and transported. When passing through the fixing device 20, the toner image on the transfer paper is fixed on the surface of the transfer paper by the action of heat and pressure. . Next, the transfer sheet is discharged as a final copy sheet onto a discharge tray 21 outside the apparatus.

  Transfer residual toner adhering to the surface of the intermediate transfer member after the toner image is transferred to the transfer paper P is removed from the surface of the intermediate transfer member by the cleaning member 23 of the cleaning device 22. The cleaning member 23 is separated from the surface of the intermediate transfer member when the toner image on the intermediate transfer member 11 before being transferred passes through the cleaning member 23.

  FIG. 2 is a cross-sectional view showing details of the rotary developing device 8. The developing device 8 includes a back side plate 24 and a front side plate 24A (see FIGS. 5, 7, and 8). These side plates 24, 24A are integrally connected by a support body 25, and the above-described developing devices 8BK, 8C, 8M, 8Y are detachably supported by the side plates 24, 24A and the support body 25, respectively. . Each developing unit has developing cases 26BK, 26C, 26M, and 26Y that store a powdery developer (not shown), and the above-described developing rollers 9BK, 9C, 9M, and 9Y, One conveying screw 27BK, 27C, 27M, 27Y and a second conveying screw 28BK, 28C, 28M, 28Y are rotatably arranged, and a doctor blade 29BK, 29C, 29M, 29Y is fixed to each developing case. Has been placed.

  The developer in the developing case 26BK of the developing device 8BK occupying the developing position facing the image carrier 5 is transported from the rotating second transport screw 28BK to the first transport screw 27BK, and the developer is clockwise. Is carried by a developing roller 9BK that rotates in a straight line. At this time, the amount of the developer conveyed by the doctor blade 29BK is regulated, and the regulated developer is carried between the developing roller 9BK and the image carrier 5, where the toner in the developer is electrostatic latent. The electrostatic latent image is electrostatically transferred to the image, and the electrostatic latent image is visualized as a toner image of a predetermined color.

  In addition, toner cartridges 30BK, 30C, 30M, and 30Y are attached to each developing device, and toner of each color is supplied from each toner cartridge to each developing case.

  In the developing device 8 described above, the support body 25 is supported so as not to rotate relative to the central shaft 31, and the central shaft 31 is supported rotatably relative to the image forming apparatus main body 1 as will be described later. Are rotated by a driving device (not shown), so that each developing device can occupy a developing position facing the image carrier 5.

  On the other hand, as shown in FIG. 3, the cleaning device 14 has a cleaning case 32 and a cleaning member that removes transfer residual toner on the surface of the image carrier. In the cleaning device 14 shown here, a base end portion is provided. A cleaning blade 33 fixed to the cleaning case 32 and having a tip edge pressed against the surface of the image carrier, and a cleaning brush 34 disposed in the cleaning case 32 and rotatably supported by the case and rotated. A member is used. The cleaning case 32 is positioned with its opening 35 facing the surface of the image carrier 5. Reference numeral 36 denotes a seal member whose one end is fixed to the cleaning case 32 and whose tip is lightly in contact with the surface of the image carrier 5.

  The transfer residual toner removed from the surface of the image carrier by the cleaning blade 33 and the cleaning brush 34 is accommodated in the cleaning case 32. At this time, the opening 35 is sealed by the sealing member 36 and the cleaning blade 33, and the toner is prevented from scattering outside the cleaning case through the opening 35.

  As shown in FIG. 3, the laser writing unit 7 includes a unit case 38 that houses the optical system, and a translucent dust-proof member made of dust-proof glass 39 attached to the opening of the case 38. The laser light L from the case 38 is emitted to the outside through the dust-proof glass 39 and irradiates the surface of the image carrier 5.

  As described above, the illustrated image forming apparatus includes an image carrier 5 on which an electrostatic latent image is formed, a charging charger 6 that is an example of a charging device that charges the surface of the image carrier 5, and a charging surface thereof. A laser writing unit 7 which is an example of an exposure device that forms an electrostatic latent image by exposing the toner, and a developing device 8 that visualizes the electrostatic latent image formed on the surface of the image carrier 5 as a toner image. And a cleaning device 14 for removing transfer residual toner adhering to the surface of the image carrier after the toner image is transferred to the transfer material.

  In this example, the toner image formed on the surface of the image carrier 5 is temporarily transferred to the surface of the intermediate transfer body 11 and then transferred to the transfer paper P. As described above, the intermediate transfer member 11 constitutes a transfer material on which the toner image is transferred from the surface of the image carrier 5. On the other hand, when the toner image on the surface of the image carrier is directly transferred to the final transfer material, for example, transfer paper without providing an intermediate transfer member, the final transfer material is used as the image carrier. It constitutes a transfer material to which a toner image on the body surface is transferred.

  By the way, the above-described image forming apparatus should be configured to facilitate maintenance work such as maintenance and inspection of each element such as the image carrier 5, the developing device 8, and the cleaning device 14, or replacement of these.

  Therefore, in the image forming apparatus of this example, as shown in FIGS. 3 and 4, the image carrier 5 is rotatably held by the unit holder 40 and is disposed around the image carrier 5. The discharge lamp 15 is also supported by the unit holder 40, and the cleaning case 32 of the cleaning device 14 is detachably fixed to the unit holder 40, and an image carrier unit 41 is constituted by these elements.

  The unit holder 40 is made of, for example, resin, and has a top plate 42 at the upper portion thereof, and a front plate 43 and a rear plate 44 that hang downward integrally at the front and rear ends thereof. As will be described later, the image carrier 5 is rotatably supported. Further, as shown in FIG. 5, the top plate 42 is formed with an opening 53 that guides the laser beam emitted from the laser writing unit 7 to the surface of the image carrier.

  As described above, in the image forming apparatus of this example, the image carrier 5 is assembled to the unit holder 40 having the opening 53 through which the light emitted from the laser writing unit 7 which is an example of the exposure apparatus passes. The image carrier unit 41 is detachably attached to the image forming apparatus main body 1.

  At this time, the image carrier unit 41 may be detachably attached to the image forming apparatus main body 1 alone, but in the illustrated example, as shown in FIGS. The body unit 41 and the developing device 8 described above are held by a drawer body 45 supported so as to be able to be pulled out toward the front side with respect to the image forming apparatus main body 1, and the drawer body 45 is pulled out from the image forming apparatus main body 1. Alternatively, the image carrier unit 41 is pulled out from the image forming apparatus main body 1 by being pushed in, or is stored in a predetermined position in the image forming apparatus main body 1. The details are clarified below.

  FIG. 5 shows a state in which the drawer body 45 is pulled out from the image forming apparatus main body 1 to the front side and the image carrier unit 41 is taken out from the drawer body 45. 6 shows a state when the image carrier unit 41 is mounted on the drawer body 45, and FIG. 7 is a horizontal sectional view showing a state when the drawer body 45 is pushed into the back side of the image forming apparatus main body 1. FIG. 8 is a horizontal sectional view after the drawer body 45 is loaded into a predetermined position of the image forming apparatus main body 1.

  As can be seen from these drawings, the drawer body 45 has a front side plate 46 on the near side, a rear side plate 47 on the back side, and an appropriate number of stays that integrally connect these side plates 46 and 47, and in the illustrated example, And four first stays 48, 49, 50, 51 on the upper and lower sides of the center, and is detachably attached to the drawer 45 below the developing device 8 supported by the drawer 45. The toner receiver 52 (FIG. 5) attached to is located. As shown in FIG. 6, the image carrier unit 41 has a top plate 42 of the unit holder 40 placed on the first and second stays 48 and 49 so as to be detachably held on the drawer 45. .

  As shown in FIGS. 7 and 8, the central shaft 31 of the developing device 8 is rotatably supported by the shaft holder 63 through the bearing at the back end region thereof. The hole 76 formed in the rear side plate 47 of the drawer body 45 is fitted in a removably and axially fixed manner with some play. The front end of the central shaft 31 is rotatably supported by the front plate 46 of the drawer body 45 via a bearing 64, so that the front side portion of the developing device 8 is correctly positioned with respect to the drawer body 45. Positioned. A knob 65 is detachably fixed to the end of the central axis on the nearer side than the front plate 46. 7 and 8, the developing roller 9BK and the first and second conveying screws 27BK and 28BK of the black developing device 8BK are shown assembled to the side plates 24 and 24A and the support body 25. The developing device is not shown.

  With the drawer body 45 pulled out to the front side as shown in FIG. 5, the developing unit located on the upper side, in the example shown in the figure, the black developing unit 8BK is removed from the support 25, or this is mounted on the support 25. be able to. By rotating the support body 25, one of the developing units can be positioned on the upper side, the developing unit can be lifted upward, and the developing unit can be detached from the support body 25 or mounted. Similarly, the image carrier unit 41 can be lifted upward and removed from the drawer body 45, or it can be attached to the drawer body 45.

  As shown in FIGS. 7, 8, and 9, the first and third stays 48 and 50 are formed with notches 54 at a predetermined interval, and the movable guide rails 55 and 56 are formed in these notches 54. The small-diameter neck portions of the locking pins 57 and 58 provided on the detachably engage with each other, whereby the drawer body 45 is supported by the movable guide rails 55 and 56. The movable guide rails 55 and 56 are slidably fitted to the fixed guide rails 61 and 62 fixed to the front side plate 59 and the rear side plate 60 of the image forming apparatus main body 1, respectively. In this way, the drawer body 45 is supported so as to be drawn out toward the front side with respect to the image forming apparatus main body 1. If the drawer body 45 is pulled out to the near side, the drawer body 45 can be easily lifted upward and removed from the movable guide rails 55 and 56.

  On the other hand, as shown in FIGS. 7 and 8, the image carrier 5 is composed of a cylindrical carrier body 66 having a photosensitive layer on the surface, and flange members 67 and 68 fixed to respective ends in the longitudinal direction. The annular flanges 67A and 68A projecting from the flange members 67 and 68 are fitted into the annular grooves 69 and 70 formed on the front and rear side plates 43 and 44 of the unit holder 40 so as to be rotatable with some play. The image carrier 5 is assembled to the unit holder 40 so as to be freely rotatable. A drive shaft holder 71 is fixed to the rear plate 60 on the back side of the image forming apparatus main body 1, and a drive shaft 72 is inserted through the center hole thereof. The drive shaft 72 includes a plurality of rolling bearings 95 and 95A. And is rotatably supported by the drive shaft holder 71.

  As shown in FIG. 7, in a state where the image carrier unit 41 and the developing device 8 are mounted on the drawer 45, the operator places the drawer 45 on the back side of the image forming apparatus main body 1, that is, the arrow C in FIG. When pushed in the direction, as shown in FIG. 8, the tip of the drive shaft 72 enters the center hole of the slide bearing 73 fixed to the rear side plate 47 of the drawer 45. Further, the front end portion of the drive shaft 72 is fitted into the rear end portion of the image carrier 5, in the illustrated example, the center hole 74 formed in the flange member 68 on the back side, and the joint 75 fixed to the drive shaft 72. Engages with an engagement surface 96 (FIG. 7) formed in the portion of the back flange member 68 adjacent to the center hole 74.

  The joint 75 has a tapered surface reduced in diameter toward the front side of the image forming apparatus main body 1, and a plurality of teeth arranged in the circumferential direction are formed on the tapered surface. The engaging surface 96 is formed in a complementary tapered surface on the tapered surface of the joint 75, and a plurality of teeth arranged in the circumferential direction are formed on the peripheral surface thereof. The tapered surface of the joint 75 and the engaging surface 96 are formed. Are engaged with each other so that they cannot engage with each other. As a result, the rear end of the back side of the image carrier 5 is positioned concentrically with respect to the drive shaft 72.

  At this time, the cylindrical boss portion 71 </ b> A of the drive shaft holder 71 is fitted into the center hole of the slide bearing 73 without rattling. At the same time, the outer race outer peripheral surface of one of the roller bearings 95 </ b> A of the pair of roller bearings that rotatably supports the drive shaft 72 on the drive shaft holder 71 is rattled in a hole 70 </ b> A formed in the rear plate 44 of the unit holder 40. Fit without any problems. Thereby, the site | part of the back side of the image carrier unit 41 is positioned.

  On the other hand, as shown in FIG. 8, the rear end of the central shaft 31 of the developing device 8 is rotatably fitted to a bearing 77 provided on the rear plate 60 of the image forming apparatus main body 1 without rattling. Accordingly, the rear side portion of the developing device 8 is positioned with respect to the image forming apparatus main body 1.

  When the drawer 45 is pushed into the back side of the image forming apparatus main body 1, the positioning holes 78 and 78 A formed in the front plate 46 of the drawer 45 as shown in FIG. Are respectively fitted to the positioning pins 79 and 79 </ b> A, and the front side of the drawer body 45 is positioned with respect to the image forming apparatus main body 1.

  After positioning the drawer 45 with respect to the image forming apparatus main body 1, the operator moves the front end of the driven shaft 81 shown in FIGS. 7 and 8 to the front end of the image carrier 5 as shown in FIG. That is, it is inserted into the center hole 80 formed at the center of the flange member 67 on the front side. At this time, the driven shaft 81 and the center hole 80 are frictionally engaged, and the relative rotation of the driven shaft 81 and the flange member 67 is prohibited. Although the driven shaft 81 is rotatable in the center hole of the driven shaft holder 82 via the rolling bearings 13 and 13A, it is fitted in the axial direction so as not to be loose. When the driven shaft 81 is inserted into the central hole 80 of the flange member 67 as described above, the hole 91 formed in the front plate 46 of the drawer 45 and the hole formed in the front plate 43 on the near side of the unit holder 40 are formed. The driven shaft holder 82 is fitted to 40A.

  The driven shaft 81 is provided with a compression coil spring 81 </ b> A wound around the driven shaft 81 so as to rotate together with the driven shaft 81. As shown in FIG. 8, the driven shaft 81 is fitted into the center hole 80 of the flange member 67 of the image carrier 5, and the driven shaft holder 82 is attached to the image forming apparatus main body 1 via a fixing member 97 as will be described later. When fixed, the spring 81A is positioned and compressed between the flange member 67 and the inner race of the rolling bearing 13, thereby pressing the image carrier 5 to the back side. In this manner, the tapered engagement surface 96 formed on the rear flange member 68 and the tapered surface of the joint 75 are firmly engaged, and relative rotation of both is reliably prohibited.

  After the drawer body 45 is positioned with respect to the image forming apparatus main body 1, the drawer body 45 is fixed to the image forming apparatus main body 1. That is, as shown in FIGS. 7 and 8, a fixing member 97 made of a plate generally called a face plate is firmly fixed to the driven shaft holder 82 by, for example, a screw (not shown). When the driven shaft 81 is fitted into the center hole 80 of the image carrier 5 and the driven shaft holder 82 is fitted into the holes 91 and 40A, the figure is projected from the front plate 59 of the image forming apparatus main body 1. A long hole (not shown) formed in the fixing member 97 is fitted into a positioning pin (not shown). As a result, the fixing member 97 is correctly positioned with respect to the image forming apparatus main body 1. Therefore, the fixing member 97 is firmly fixed to the front side plate 59 of the image forming apparatus main body 1 and the front side plate 46 of the drawer 45 by screws (not shown). In this way, the elements such as the image carrier 5 and the drawer 45 are correctly positioned and assembled with respect to the image forming apparatus main body 1.

  When the image forming operation is started in the above-described state, a pulley 83 fixed to the drive shaft 72 as shown in FIG. 8 passes through a belt (not shown) wound around the pulley and other transmission elements. The image carrier 5 is rotated by a driving device (not shown) and the rotation is transmitted to the image carrier 5 to rotate the image carrier 5. At this time, the driven shaft 81 also rotates together with the image carrier 5. Further, the developing device 8 and each element thereof are also driven as described above by a driving device (not shown), and the above-described image forming operation is executed.

  When it is necessary to remove the image carrier unit 41 or the developing device, the operation of the image forming apparatus is stopped, the screws (not shown) are removed, and the fixing member 97, the driven shaft holder 82, and the driven shaft 81 are removed. 7 is detached from the image forming apparatus main body 1 as shown in FIG. 7, and the drawer body 45 is pulled out to the front side, that is, in the direction of arrow B in FIG. 8, and the drawer body 45 is shown in FIG. Stop at position. Thereby, the image carrier unit 41 and a desired developing device can be lifted upward and removed from the drawer 45. Further, the entire developing device 8 can be removed from the drawer 45 by removing the knob 65, the bearing 64, and the shaft holder 63 from the central shaft 31 of the developing device 8.

  In this way, the image carrier unit 41 is detachably held and the drawer 45 holding the developing device 8 is detachably attached to the image forming apparatus main body 1, so that the image carrier 5 is attached to the unit holder. 40 can be easily removed or set. Further, in this example, since the developing device 8 and each developing device thereof are assembled to the drawer body 45 so as to be attachable / detachable, they can be easily detached from the drawer body 45 or set. The operator can easily perform maintenance work while standing on the front side or the side of the drawer 45 without taking an unreasonable posture.

  As described above, in the image forming apparatus of this example, the image carrier 5 is assembled to the unit holder 40 to constitute the image carrier unit 41. Therefore, the image carrier unit 41 is installed in the image forming apparatus main body 1. As shown in FIG. 3, when the image forming operation is performed at a predetermined position, an opening 53 is formed in the unit holder 40 so that the light emitted from the optical writing unit 7 reaches the surface of the image carrier 5. doing. At that time, when the image carrier unit 41 is pulled out to the outside of the image forming apparatus main body 1 by pulling out the drawer 45 toward the front side, if the opening 53 remains open, external light, For example, light in a room in which the image forming apparatus is installed may enter the unit holder 40, and the light may strike the surface of the image carrier to partially degrade the image carrier 5. Since the opening 53 opens upward, light from an indoor lighting fixture or the like directly enters the inside of the unit holder 40 through the opening 53.

  Further, as in the image forming apparatus of this example, when the image carrier unit 41 is held together with the developing device 8 on the drawer 45, the developing device 8 and the image carrier 5 are cleaned and the developer is kept pulled out. Since a relatively long time is required for the work, such as replacement of the developing device and replacement of the developing device, the possibility that the image carrier 5 is deteriorated by light incident from the opening 53 during that time increases.

  Therefore, in the image forming apparatus of this example, as shown in FIGS. 3, 4, and 10, a shutter 84 that closes or opens the opening 53 formed in the unit holder 40 is provided. This shutter 84 is shown in FIGS. 4 and 10 when the image carrier unit 41 is pulled out from the main body of the image forming apparatus by pulling the drawer 45 to the near side, and as shown by a chain line in FIG. When the image carrier unit 41 is accommodated in a predetermined position in the image forming apparatus main body by occupying a closed position for closing the opening 53 formed in the unit holder 40 and pushing the drawer 45 to the back side, FIG. As indicated by the solid line, the opening 53 is opened and closed so as to occupy the open position.

  In the example shown in the figure, concentric rotating shafts 85 and 85A integrally formed at each end portion in the longitudinal direction of the shutter 84 formed in an elongated plate shape are rotatably fitted in holes formed in the unit holder 40. The shutter 84 is supported by the unit holder 40 so as to be rotatable between the open position indicated by the solid line in FIG. 3 and the closed position indicated by the chain line around the central axis of the rotation shafts 85 and 85A. Has been.

  When the image carrier unit 41 is set at a predetermined position in the image forming apparatus main body, the shutter 84 occupies the open position, so that the laser light L emitted from the optical writing unit 7 is obstructed by the shutter 84. Without reaching the surface of the image carrier 5, an electrostatic latent image is formed there. When the drawer body 45 is pulled to the front side and the image carrier unit 41 is pulled out of the image forming apparatus main body, the shutter 84 closes the opening 53, so that indoor light passes through the opening 53 and the image carrier 5 It does not reach the surface, and it is possible to prevent the image carrier from deteriorating at an early stage.

  At that time, since the shutter 84 is provided in the unit holder 40 of the image carrier unit 41 as described above, the image carrier unit 41 is detached from the drawer 45 as shown in FIG. Even when the body unit 41 is completely detached from the image forming apparatus main body 1, the opening 53 can be closed by the shutter 84, and the image carrier 5 can be reliably protected from external light.

  The shutter 84 may be configured to be manually rotated to the closed position and the open position. However, when configured in this manner, the image carrier unit 41 is pulled out of the image forming apparatus main body or is When setting in the image forming apparatus main body, the operator may forget to close the shutter 84 or forget to open it.

  Therefore, in the image forming apparatus of this example, when the image carrier unit 41 is pulled out from the main body of the image forming apparatus, the shutter 84 operates to a closed position that closes the opening 53 in accordance with the movement of the image carrier unit 41. When the unit 41 is housed in a predetermined position in the image forming apparatus main body, the shutter 84 is configured to operate to an open position that opens the opening 53 in accordance with the movement. Thus, if the shutter 84 opens and closes in conjunction with the opening and closing operation of the drawer 45, in other words, the opening and closing operation of the image carrier unit 41, there is no possibility that the operator forgets to open or close the shutter 84.

  More specifically, as shown in FIG. 10, a torsion coil spring 86 is wound around one rotating shaft 85 integrally attached to the shutter 84, and each end thereof is formed on the unit holder 40. The stopper 84 and the shutter 84 are engaged with each other, whereby the shutter 84 is urged to rotate toward the closed position where the opening 53 is closed. The rotating shaft 85 passes through the wall portion 40A of the unit holder 40 in a rotatable manner, and a connecting plate 88 (see also FIG. 3) is integrally connected to an outer end portion thereof. The connecting plate 88 is located outside the unit holder 40, and the connecting plate 88 is integrally provided with a regulating member 89 that protrudes from the center axis of the rotation shaft 85 toward the back side of the image forming apparatus main body. Is provided.

  The rotating shaft 85, the torsion coil spring 86 wound around the rotating shaft 85, and the region provided with the engaging portion 87 are made of a sheet-like light shielding member 90 having flexibility, particularly elasticity, such as rubber or foam. (See FIG. 4 and FIG. 5), and the light shielding member 90 is bonded to the unit holder 40 with an adhesive at a portion hatched with a chain line in FIG. The light shielding member 90 serves to prevent external light from entering the unit holder 40 from the region where the torsion coil spring 86 is provided.

  When the drawer 45 is pulled toward the front side of the image forming apparatus main body and the image carrier unit 41 is pulled out of the image forming apparatus main body, the shutter 84 is shown in FIG. 10 by the biasing action of the torsion coil spring 86 described above. Occupy the closed position. This prevents external light from entering the inside of the unit holder 40 through the opening 53. Thus, the torsion coil spring 86 constitutes an example of a biasing unit that biases the shutter 84 to its closed position.

  When the drawer 45 is pushed in the direction of arrow C in FIG. 7 and the image carrier unit 41 is stored in a predetermined position in the image forming apparatus main body 1 as described above, the drawer 45 and the image carrier unit 41 are stored. At a point just before the position is set at a predetermined position, the above-described restricting member 89 enters the guide hole 92A of the guide member 92 fixed to the image forming apparatus main body as shown in FIG.

  The guide hole 92A is formed in an arc shape along the turning locus of the restricting member 89 when the shutter 84 is rotated around the central axis of the rotation shaft 85, and the bottom 92B of the guide hole 92A is in front of the guide hole 92A. It is smoothly inclined from the side end portion 92B1 toward the back end portion 92B2.

  As described above, the restricting member 89 enters the guide hole 92A of the guide member 92. At this time, the tip of the restricting member 89 enters the portion of the guide hole 92A corresponding to the end portion 92B1 on the near side. Therefore, as the image carrier unit 41 moves to the back side (in the direction of arrow C in FIG. 10), the tip of the regulating member 89 first hits the end 92B1 on the near side of the bottom 92B. In this state, when the drawer 45 is further pushed into the back side and the image carrier unit 41 is moved to the back side, the leading end of the regulating member 89 slides on the bottom side 92B1 while sliding on the bottom 92B. It moves to end part 92B2. For this reason, the regulating member 89 rotates together with the shutter 84 against the action of the torsion coil spring 86 around the central axis of the rotary shaft 85 in the direction indicated by the arrow D in FIG. When the unit 41 is housed in a predetermined position in the image forming apparatus main body 1, the shutter 84 occupies the open position shown by the solid line in FIG. Thus, the shutter 84 automatically operates to the open position when the image carrier unit 41 is mounted in the image forming apparatus main body 1.

  When the drawer body 45 is pulled again toward the front side (in the direction of arrow B in FIG. 7), the regulating member 89 operates in the opposite direction to that described above, and the shutter 84 operates in the closed position by the biasing action of the torsion coil spring 86. . Thus, the shutter 84 can be opened and closed automatically.

  When the image carrier unit 41 is housed in a predetermined position in the image forming apparatus main body, the above-described guide member 92 resists the action of the urging means comprising the torsion coil spring 86 and the shutter 84 is in its open position. An example of the guide means for guiding the shutter 84 is configured to operate.

  In the illustrated example, the lower part of the unit holder 40 and the lower part of the drawer body 45 are open, so that when the drawer body 45 is pulled out to the near side, indoor light passes through the lower part of the drawer body 45 and the unit holder. Although it reaches the lower part of the image carrier 5, generally there is little light entering the lower part of the image carrier, the deterioration of the image carrier due to this light is negligible. Of course, when the lower part and the side part of the unit holder 40 and the lower part of the drawer body 45 are covered by a cover member (not shown) and the drawer body 45 is pulled out to the front side of the image forming apparatus main body 1, the image carrier is exposed from the lower part. If it is configured so as to prevent light from penetrating into 5, it is possible to more reliably prevent the image carrier 5 from deteriorating.

  The present invention is not limited to a color image forming apparatus, but can be widely applied to an image forming apparatus that forms a single-color visible image, and an image forming apparatus such as a printer, a facsimile, or a complex machine thereof. Furthermore, an image forming apparatus that directly transfers the toner image formed on the surface of the image carrier to the final transfer material without transferring it to the intermediate transfer body, and an exposure device that directly images the original image on the surface of the image carrier. The present invention can be widely applied to the image forming apparatus used. Further, the present invention can also be applied to an image forming apparatus in which the image carrier unit is supported so as to be able to be directly pulled out from the main body of the image forming apparatus without using a drawer.

2 is a schematic cross-sectional view showing the internal structure of the image forming apparatus from the front side thereof. FIG. FIG. 2 is an enlarged sectional view showing details of the developing device shown in FIG. 1. It is sectional drawing which shows the image carrier which comprises an image carrier body unit, a cleaning apparatus and a unit holder, and a laser writing unit. It is a perspective view of an image carrier unit. FIG. 4 is a perspective view showing a state in which the drawer is pulled out to the front side of the image forming apparatus main body, and the image carrier unit and one developing device are removed from the drawer. It is a fragmentary sectional view showing the outline of the relative positional relationship between the drawer and the image carrier unit supported by the drawer. FIG. 5 is a horizontal sectional view when the drawer is pushed into the back side of the image forming apparatus main body. FIG. 6 is a horizontal sectional view after the drawer is set in the image forming apparatus main body. It is a figure explaining the assembly | attachment state of a 1st and 3rd stay and a movable guide rail. It is the perspective view which shows the torsion coil spring which urges | biases a shutter, and the guide member which guides a shutter, Comprising: It is the figure which removed the light-shielding member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 5 Image carrier 8 Developing device 40 Unit holder 41 Image carrier unit 45 Drawer 53 Opening 84 Shutter L Light

Claims (6)

An image carrier on which an electrostatic latent image is formed, a charging device for charging the image carrier, an exposure device for exposing the charged surface to form an electrostatic latent image, and the electrostatic latent image as a toner image In an image forming apparatus comprising a developing device that visualizes as a
The image carrier is assembled to a unit holder having an opening through which light emitted from the exposure apparatus passes, to form an image carrier unit, and the image carrier unit is mounted so that it can be pulled out from the image forming apparatus main body. When the image carrier unit is pulled out from the image forming apparatus main body, the image carrier unit occupies a closed position for closing the opening formed in the unit holder, and the image carrier unit is placed at a predetermined position in the image forming apparatus main body. An image forming apparatus comprising a shutter that opens and closes to occupy an open position for opening the opening when stored. The image forming apparatus according to claim 1, wherein the image carrier unit and the developing device are held by a drawer that is supported so as to be drawable with respect to the main body of the image forming apparatus. 3. The image forming apparatus according to claim 1, wherein when the image carrier unit is pulled out from the main body of the image forming apparatus, the shutter operates in a closed position that closes the opening in accordance with the movement thereof. 4. The shutter according to claim 1, wherein when the image carrier unit is stored in a predetermined position in the main body of the image forming apparatus, the shutter operates in an open position that opens the opening in accordance with the movement. 5. Image forming apparatus. An urging means for urging the shutter to its closed position; and when the image carrier unit is stored in a predetermined position in the main body of the image forming apparatus, the shutter is moved against the action of the urging means. The image forming apparatus according to claim 1, further comprising a guide unit that guides the shutter so as to operate to the open position. The image forming apparatus according to claim 1, wherein the shutter is provided in an image carrier unit.

Images