JP4355606B2 - Image forming apparatus - Google Patents

Description

  The present invention provides an image forming apparatus using an electrophotographic system in which a plurality of image forming stations are arranged in parallel in a vertical direction, and a process cartridge having a drum shutter for protecting an image carrier is detachably attached to each image forming station. It is about.

  Here, an image forming apparatus using an electrophotographic system is an apparatus that forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser printer, an LED printer, etc.), a facsimile apparatus, a word processor, and a complex machine thereof (multifunction printer, etc.).

  The process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member as an image carrier are integrally formed, and the cartridge can be attached to and detached from the image forming apparatus main body. is there. Alternatively, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive member are integrated into a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrated into a cartridge so as to be detachable from the image forming apparatus main body.

Japanese Patent Application Laid-Open No. 2004-228561 describes that a process cartridge is provided with a protective member in order to prevent the photosensitive member from being exposed to light by opening the opening / closing part. Further, when the opening / closing plate 29 provided in the image forming apparatus rises in the A direction, the protective member opening / closing lever 28 rotatably attached to the attachment portion 25b of the frame body 25 is moved in the B direction centering on the attachment portion 25b. The structure in which the protective member 26 is opened by rotating is described.
JP 2003-241617 A

  An object of the present invention is to provide an image forming apparatus that can further reduce the exposure of a photosensitive drum to light while improving the usability of attaching / detaching a process cartridge by further developing a conventional configuration.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides an image forming apparatus for forming an image on a recording medium.
(I) a photosensitive member, a shutter for protecting the photosensitive member, a plurality having a closed position covering the photosensitive member, wherein the open photoreceptor Ru exposed position, a shutter which can be taken, and the An image forming station in which the process cartridges are detachably mounted in parallel in the vertical direction;
(Ii) An opening / closing door that opens and closes to attach the process cartridge to the image forming station, and has a center of rotation below the image forming station in the vertical direction. A door that is rotatable about a rotation axis parallel to the longitudinal axis of the process cartridge ;
(Iii) A link mechanism for opening and closing the shutters of the plurality of process cartridges in conjunction with opening and closing operations of the opening and closing doors, wherein the process cartridge is mounted at a position other than the lowest when the opening and closing doors are opened. A link mechanism for moving the shutter to the closed position earlier than the shutter of the process cartridge mounted at the lowermost position, wherein the open / close door is at an angle at which the process cartridge mounted at a position other than the lowermost position can be taken out. A link mechanism configured to position the shutter in the closed position in a state where the shutter is open;
An image forming apparatus comprising:

According to one embodiment of the present invention, the link mechanism is moved when opening the door, the shutter of the process cartridge mounted in sequence downward from the process cartridge is mounted to the top upwardly to the closed position To be configured.

According to another embodiment of the present invention, the link mechanism is configured to simultaneously move the shutters of the other process cartridges to the open position or the closed position.

According to another embodiment of the present invention, the link mechanism comprises:
Link means that rotates in conjunction with the opening and closing door;
A rack means for converting the rotational force of the link means in the longitudinal direction,
Shutter opening and closing means arranged to transmit the force of the rack means to each of the shutters to move each of the shutters ;
Have

According to another embodiment of the present invention, the link means includes a first cam that rotates in conjunction with the opening and closing door, and a second cam that is rotated by the first cam,
The rack means extends in the vertical direction along the plurality of image forming stations arranged side by side in the vertical direction, and is provided with an elongated rack member movably provided in the vertical direction, and the rack member. And a cam member for adjusting the operation timing of the shutter opening / closing means to determine the opening / closing timing of the shutter.

According to another embodiment of the present invention, the shutter includes a shutter member that rotates about a rotation axis parallel to the longitudinal axis of the process cartridge, and an urging force that biases the shutter member to the closed position. A biasing member and an opening / closing member that can be engaged with the shutter opening / closing means, and the opening / closing member is rotated against the biasing force of the biasing member by the operation of the shutter opening / closing means. By doing so, the shutter member is moved to the open position.

According to another embodiment of the present invention, the image forming station is inclined with respect to the longitudinal direction.

According to the present invention, when the opening / closing door of the image forming apparatus is opened, the exposure amount of the photosensitive member of each image forming station can be minimized. Further, according to the present invention, even when taken out of the process cartridge in a state of open minimum degree retrieve the door the process cartridge, it is possible to close the sheet Yatta, fear without process cartridge damaging the sheet Yatta It can be taken out.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

Example 1
FIG. 1 shows the overall configuration of a color electrophotographic image forming apparatus which is an embodiment of an image forming apparatus according to the present invention. First, the overall configuration of the color electrophotographic image forming apparatus will be described with reference to FIG.

(Overall configuration of image forming apparatus)
Referring to FIG. 1, the color electrophotographic image forming apparatus includes a plurality of image forming stations Pa, Pb, Pc, and Pd arranged in the vertical direction in the image forming apparatus main body 100 in this embodiment. The process cartridges 7 (7a, 7b, 7c, 7d) are detachably attached to the image forming stations Pa, Pb, Pc, Pd by attachment means (not shown).

  In this embodiment, the image forming stations Pa, Pb, Pc, and Pd are arranged side by side with a slight inclination in the vertical direction, but may be arranged in the vertical direction without being inclined.

  Each cartridge 7 (7a, 7b, 7c, 7d) has a drum-shaped electrophotographic photosensitive member (referred to as “photosensitive drum” in this specification) 1 (1a, 1b, 1c, 1d) as an image carrier. I have. The photosensitive drum 1 is driven to rotate counterclockwise in the drawing by a driving means (not shown). The photosensitive drum 1 is irradiated with a laser beam on the basis of the image information, charging means 2 (2a, 2b, 2c, 2d) for uniformly charging the surface of the photosensitive drum 1 in order according to the rotation direction. A scanner unit 3 (3a, 3b, 3c, 3d) for forming an electrostatic latent image on the drum 1, and a developing means 4 (4a, 4b, 4c, 4d) for developing the toner image by attaching toner to the electrostatic latent image ), An electrostatic transfer device 5 for transferring the toner image on the photosensitive drum 1 to a transfer material S as a recording medium, and a cleaning means 6 (6a, 6) for removing transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer. 6b, 6c, 6d) and the like are provided.

  Here, the photosensitive drum 1, the charging unit 2, the developing unit 4, and the cleaning unit 6 are integrally formed into a cartridge to form a process cartridge 7.

  Hereinafter, the photosensitive drum 1 will be described in detail sequentially with reference to FIG.

  The photosensitive drum 1 (1a, 1b, 1c, 1d) is configured by providing a photosensitive layer on the outer peripheral surface of an aluminum cylinder having a diameter of 24 mm, for example. Both ends of the photosensitive drum 1 are rotatably supported by a support member, and a driving force from a driving motor (not shown) is transmitted to one end, so that the photosensitive drum 1 is rotated counterclockwise. The

  As the charging means 2 (2a, 2b, 2c, 2d), a contact charging type can be used. The charging member is a conductive roller formed in a roller shape. The roller is brought into contact with the surface of the photosensitive drum 1 and the surface of the photosensitive drum 1 is made uniform by applying a charging bias voltage to the roller. To be charged. In this embodiment, since the reversal development system is used, the surface of the photosensitive drum 1 is charged with a negative polarity.

  In the scanner unit 3 (3a, 3b, 3c, 3d), a laser diode (not shown) passes image light corresponding to an image signal through a polygon mirror (not shown) and an imaging lens (not shown) rotated at high speed. The surface of the charged photosensitive drum 1 is selectively exposed to form an electrostatic latent image.

  The developing means 4 (4a, 4b, 4c, 4d) is composed of a toner container 41 containing toner of each color of yellow, magenta, cyan, and black, respectively, and the toner in the toner container 41 is supplied by the feeding mechanism 42. Feed to roller 43.

  The toner supply roller 43 rotates in the clockwise direction in the drawing to supply toner to the developing sleeve 40 as a developer carrying member and to tear off the toner from the developing sleeve 40 after developing to the photosensitive drum 1. I do.

  The toner supplied to the developing sleeve 40 is applied to the outer periphery of the developing sleeve 40 that rotates in the clockwise direction in the figure by a developing blade 44 that is pressed against the outer periphery of the developing sleeve 40, and is given an electric charge. Then, a developing bias is applied to the developing sleeve 40 facing the photosensitive drum 1 on which the latent image is formed, whereby toner development is performed on the photosensitive drum 1 in accordance with the latent image.

  The electrostatic transfer device 5 is provided with an electrostatic transfer belt 11 that circulates and moves so as to face and contact all the photosensitive drums 1 (1a, 1b, 1c, 1d). The electrostatic transfer belt 11 uses a resin film or a multilayer film-like member in which a resin layer is provided on a rubber base layer. The electrostatic transfer belt 11 is stretched around a driving roller 13, driven rollers 14a and 14b, and a tension roller 15, and electrostatically adsorbs a transfer material S as a recording medium on the outer peripheral surface on the left side in the drawing, thereby performing the above-described photosensitive operation. The transfer material S is circulated so as to contact the body drum 1. As a result, the transfer material S is conveyed to the transfer position by the electrostatic transfer belt 11, and the toner image on the photosensitive drum 1 is transferred.

  The transfer rollers 12 (12a, 12b, 12c, 12d) are arranged in parallel at positions facing the inside of the electrostatic transfer belt 11 and facing the four photosensitive drums 1 (1a, 1b, 1c, 1d). . A positive polarity bias is applied to the transfer rollers 12 at the time of transfer, and a positive polarity charge is applied to the transfer material S via the electrostatic transfer belt 11. The negative polarity toner image on the photosensitive drum 1 is transferred to the transfer material S in contact with the photosensitive drum 1 by the electric field generated at this time.

  The paper feeding unit 16 feeds and conveys a transfer material S as a recording medium to an image forming station, and a plurality of transfer materials S are stored in a paper feeding cassette 17. At the time of image formation, the paper feed roller 18 (half-moon roller) and the registration roller 19 are driven and rotated in accordance with the image forming operation to separate and feed the transfer material S in the paper feed cassette 17 one by one, and at the front end of the transfer material S , Abuts against the registration roller 19 and temporarily stops. After a loop is formed, the rotation of the electrostatic transfer belt 11 and the image writing position are synchronized, and the sheet is fed to the electrostatic transfer belt 11 by the registration roller 19.

  The fixing unit 20 fixes a plurality of color toner images transferred to the transfer material S, and includes a heating roller 21a that rotates, and a pressure roller 21b that presses and applies heat and pressure to the transfer material S. Consists of. That is, the transfer material S to which the toner image on the photosensitive drum 1 is transferred is conveyed by the pressure roller 21b when passing through the fixing unit 20, and is also given heat and pressure by the heating roller 21a. As a result, the toner images of a plurality of colors are fixed on the surface of the transfer material S.

  As an image forming operation, the process cartridge 7 (7a, 7b, 7c, 7d) is sequentially driven in accordance with the printing timing, and the photosensitive drums 1a, 1b, 1c, 1d are rotated counterclockwise in accordance with the drive. It is rotationally driven in the direction. Then, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven. By this driving, the charging roller 2 imparts a uniform charge to the circumferential surface of the photosensitive drum 1, and the scanner unit 3 exposes the circumferential surface of the photosensitive drum 1 according to the image signal to perform photosensitive drum 1. An electrostatic latent image is formed on the peripheral surface. The developing sleeve 40 in the developing unit 4 forms (develops) a toner image on the circumferential surface of the photosensitive drum 1 by transferring the toner to the low potential portion of the electrostatic latent image.

  At the timing when the leading edge of the toner image formed on the peripheral surface of the most upstream photosensitive drum 1 is rotated and conveyed to a point facing the electrostatic transfer belt 11, the printing start position of the transfer material S is reached at that point. So that the registration rollers 19 start rotating, and the transfer material S is fed to the electrostatic transfer belt 11.

  The transfer material S is pressed against the outer periphery of the electrostatic transfer belt 11 so as to be sandwiched between the electrostatic adsorption roller 22 and the electrostatic transfer belt 11, and a voltage is applied between the electrostatic transfer belt 11 and the electrostatic adsorption roller 22. By applying the charge, a charge is induced in the transfer material S which is a dielectric and the dielectric layer of the electrostatic transfer belt 11, and the transfer material S is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11. . As a result, the transfer material S is stably adsorbed to the electrostatic transfer belt 11 and conveyed to the most downstream transfer unit.

  While being conveyed in this way, the toner image on each photoconductive drum 1 is sequentially transferred to the transfer material S by an electric field formed between each photoconductive drum 1 and the transfer roller 12.

  The transfer material S on which the toner images of four colors are transferred is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13 and is carried into the fixing unit 20. After the toner image is thermally fixed by the fixing unit 20, the transfer material S is discharged by the paper discharge roller 23 from the paper discharge unit 24 to the outside of the main body with the image surface facing down.

(Process cartridge configuration)
Next, the process cartridge embodying the present invention will be described in detail with reference to FIGS.

2 and 3 are a main cross-sectional view and a perspective view of the process cartridge 7 containing toner. Incidentally, the yellow, magenta, cyan, process cartridges 7a of black, 7b, 7c, 7d have the same configuration.

  The process cartridge 7 is divided into a photosensitive drum 1, a cleaner unit 50 having a charging unit 2 and a cleaning unit 6, and a developing unit 4A having a developing unit 4 for developing an electrostatic latent image on the photosensitive drum 1. Yes.

  The photosensitive drum 1 is rotatably attached to a cleaning frame 51 constituting the cleaner unit 50 via a bearing member (not shown).

  A primary charging means 2 for uniformly charging the photosensitive layer provided on the outer peripheral surface of the photosensitive drum 1 is provided on the periphery of the photosensitive drum 1, and a developer (residual) remaining on the photosensitive drum 1 after transfer. A cleaning blade 60 and the like for removing toner are disposed. Further, residual toner (waste toner) removed from the surface of the photosensitive drum 1 by the cleaning blade 60 is stored in a waste toner chamber 55 provided in the cleaning frame 51.

  The developing unit 4A includes a developing frame 45 (45a, 45b) that stores toner. The developing frame bodies 45a and 45b are coupled (coupled by ultrasonic welding or the like) to constitute the developing container unit 46. A developing sleeve 40 that rotates in the direction of arrow Y while maintaining a slight gap with respect to the photosensitive drum 1 is rotatably supported by the developing container unit 46 via a bearing member. Further, on the circumference of the developing sleeve 40, a toner supply roller 43 and a developing blade 44 that are in contact with the developing sleeve 40 and rotate in the direction of arrow Z are disposed. Further, a toner transport mechanism 42 for stirring the toner contained in the developer container unit 46 and transporting the toner to the toner supply roller 43 is provided.

  The developing unit 4A aligns the coupling holes 47 and 48 provided at both ends of the developing container unit 46 with the support holes 52 and 53 provided at both ends of the cleaning frame 51 of the cleaner unit 50, and connects the pins 49 from both ends of the cleaner unit 50. The entire developing unit 4A is suspended so as to be swingable with respect to the cleaner unit 50 by being inserted.

  Further, the developing unit 4A is always urged by a pressure spring (not shown) so that the developing sleeve 40 contacts the photosensitive drum 1 around the support holes 52 and 53.

  At the time of development, the toner stored in the toner container 41 is conveyed to the toner supply roller 43 by the toner stirring mechanism 42. A toner supply roller 43 that rotates in the arrow Y direction supplies the toner to the developing sleeve 40 by rubbing against the developing sleeve 40 that rotates in the arrow Z direction, and carries the toner on the developing sleeve 40. The toner carried on the developing sleeve 40 reaches the developing blade 44 as the developing sleeve 40 rotates, and the developing blade 44 regulates the toner to form a predetermined toner thin layer, and a desired charged charge amount. Is granted. As the developing sleeve 40 rotates, the toner thinned on the developing sleeve 40 is transported to the developing unit where the photosensitive drum 1 and the developing sleeve 40 approach each other, and the developing unit supplies power to the developing sleeve 40 from a power source (not shown). The applied developing bias adheres to the electrostatic latent image formed on the surface of the photosensitive drum 1 and develops the latent image. The toner remaining on the surface of the developing sleeve 40 without contributing to the development of the electrostatic latent image is returned to the developing container unit 46 with the rotation of the developing sleeve 40 and is rubbed with the toner supply roller 43. It is peeled off and collected from the developing sleeve 40. The collected toner is stirred and mixed with the remaining toner by the toner stirring mechanism 42.

(Method for attaching / detaching process cartridge to / from image forming apparatus main body)
Next, a method for attaching / detaching the process cartridge 7 to / from the image forming apparatus main body 100 will be described with reference to FIGS. 4 and 10.

  As shown in FIGS. 4 and 10, the image forming apparatus main body 100 is provided with an open / close door (front door) 101 that can swing around a support shaft 102. The support shaft 102 is provided in the longitudinal direction (vertical direction) of the image forming apparatus main body 100 below the mounting portion for mounting the process cartridge at the lowest level. In the vertical direction (direction intersecting the horizontal direction), the opening / closing door (front door) 101 opens on the mounting portion side where the process cartridge is mounted on the uppermost stage. Further, as will be described in detail later, the electrostatic transfer device 5 is attached to the back of the front door 101 using link means, and swings about the support shaft 103 as the front door 101 swings. It is possible. With the front door 101 and the electrostatic transfer device 5 opened, the process cartridge 7 can be attached to and detached from the image forming apparatus main body 100. A handle member 90 is provided in the vicinity of the photosensitive drum support at both ends of the process cartridge 7 and protrudes toward the front door of the main body when the cartridge is attached or detached.

  In the process cartridge 7, a guide rail portion (not shown) provided for each image forming station in the image forming apparatus main body 100 and an insertion guide portion 54 provided in the process cartridge 7 are engaged with each other. The image forming apparatus main body 100 is detachably mounted after being positioned at a predetermined position.

(Drum shutter configuration)
Next, the configuration of the drum shutter of the process cartridge will be described with reference to FIGS. 2, 3, and 5 to 8. 6 and 7 are perspective views of members constituting the drum shutter.

  As shown in FIG. 2, when the process cartridge 7 is not attached to the apparatus main body 100, the exposed portion 76 of the photosensitive drum 1 is covered and protected by the drum shutter 70.

  In the present embodiment, the drum shutter 70 is not limited to this, but the two shutter members, that is, the first shutter 71 covering the downstream side of the exposed portion 76 in the rotation direction of the photosensitive drum, and the exposure. The second shutter 72 covers the upstream side of the section 76. As shown in FIGS. 6 and 7, the first and second shutters 71 and 72 are both made up of a resin flat plate having a thickness of about 1 to 3 mm.

  As shown in FIG. 6, the first shutter 71 has U-groove mounting portions 71a and 71b at both ends in the longitudinal direction (that is, the longitudinal direction of the process cartridge 7 which is the axial direction of the photosensitive drum 1). It has. The attachment portions 71a and 71b are fitted to support shafts 51a and 51b formed on the cleaning frame 51 as shown in FIGS. The first shutter 71 is rotatably attached to the cleaning frame 51 with the rotation shaft 74 as a line connecting the centers of both the support shafts 51a and 51b. Further, at least one side is provided with connecting grooves 71d and 71e (both end portions are described in this embodiment) for connecting to a second shutter 72 described later and for restricting movement at the time of opening and closing. The connecting grooves 71d and 71e are formed in a long hole shape along the short direction of the shutter 71 and open at least in the inner direction (the direction of the groove 71e with respect to the longitudinal direction). In this embodiment, the connecting grooves 71d and 71e are long holes penetrating in the longitudinal direction, as in the schematic view shown in FIG.

  In addition, an opening / closing pin 71c protrudes at one end portion in the longitudinal direction of the shutter 71 in the outer side in the longitudinal direction. Although the opening / closing pin 71 will be described in detail later, when the opening / closing operation member (arm member) 202 (see FIG. 12) provided on the apparatus main body side is pressed in the direction of arrow F in FIG. Functions as an open / close operated member that opens and closes.

  As shown in FIG. 7, the second shutter 72 includes shaft-shaped attachment portions 72 a and 72 b at both ends in the longitudinal direction (the axial direction of the photosensitive drum 1). As shown in FIGS. 3 and 5, the attaching portions 72 a and 72 b are fitted into frame body attaching portions 45 c and 45 d having U grooves formed in the developing device frame 45, so that the second shutter 72 can freely rotate. It is attached to. Accordingly, the second shutter 72 is rotatable with respect to the developing frame 45 with a line connecting the centers of both frame mounting portions 45c and 45d as the rotation shaft 75.

  As shown in FIG. 5, the attachment portions 71 a and 71 b of the first shutter 71 are more outward in the longitudinal direction (axial direction of the photosensitive drum 1) than the attachment portions 72 a and 72 b of the second shutter 72. Is provided.

  Further, at least one side of the second shutter 72 is engaged with the connecting grooves 71d and 71e of the first shutter 71 described above at both ends in this embodiment, and the second shutter 72 is interlocked when the shutter 71 is opened and closed. Connection shafts 72c and 72d for restricting the movement of the second shutter 72 are provided. The connecting shafts 72c and 72d are provided between the mounting portions 71a and 71b of the first shutter 71 and the mounting portions 72a and 72b of the second shutter 72 in the longitudinal direction (the axial direction of the photosensitive drum 1). Yes.

  The drum shutter 70 (71, 72) is returned as a drum shutter urging member so that the drum shutter 70 covers the exposed portion 76 of the photosensitive drum 1 when the process cartridge 7 is not attached to the apparatus main body. It is biased by a spring 73. The drum shutter urging spring 73 is a torsion coil spring, and the center of the moment is attached so as to be coaxial with the rotation shaft 74 of the first shutter 71.

Further, the first shutter 71 is provided with a notch 71g which is an escape portion so as not to interfere with the frame attachment portions 45c and 45d when the first shutter 71 is in an opened state. Further, the second shutter 72 is also provided with a hole 72f that is an escape portion so as not to interfere with the frame attachment portions 45c and 45d when the second shutter 72 is in an open state. Thus, the first shutter 71, and, without the second shutter 72 from interfering frame mounting portion 45 c, and 45d, can be open wide in space saving pace.

(Drum shutter opening / closing mechanism)
Next, the drum shutter opening / closing mechanism will be described with reference to FIGS. 3, 5, and 8. FIG. FIG. 5 is a perspective view showing a state where the drum shutters 70 (71, 72) of the process cartridge are completely opened, and FIG. 8 is a process “C”, “D” during the opening / closing of the drum shutters 70 (71, 72). , “E”. 8A and 8B are perspective views of the drum shutter, and FIG. 8C schematically shows the relationship between the photosensitive drum 1 and the drum shutters 70 (71, 72). It is sectional drawing represented.

  3 shows a state in which the exposed portion 76 (see FIG. 2) of the photosensitive drum 1 is covered with the drum shutter 70 (71, 72) by the biasing force of the shutter return spring 73 (“C” in FIG. 8). ”State). In this state, after the user inserts the process cartridge 7 into the apparatus main body 100, the opening / closing operation member 202 (FIG. 12) of the apparatus main body is moved in the direction of arrow F in FIG. It moves, contacts the opening / closing pin (opening / closing operated member) 71c of the first shutter 71, and tries to push down the pin 71c. By this operation, the first shutter 71 rotates clockwise around the rotation shaft 74 in FIG.

  Accordingly, as described above, since the connecting shafts 72c and 72d of the second shutter 72 are engaged with the connecting grooves 71d and 71e of the first shutter 71, the connecting shafts 72c and 72d are relatively connected to each other. 71d and 71e are regulated in the direction of “B” (see FIG. 8B), and the second shutter 72 rotates around the rotation shaft 75.

  When the first shutter 71 rotates by a certain angle, the second shutter 72 also rotates by a different angle (state “D” in FIG. 8 during opening and closing). In addition, since the central axis of the rotation shaft 74 is parallel to the central axis of the rotation shaft 75 and is disposed on the upstream side in the rotation direction of the photosensitive drum 1, when the first shutter 71 further rotates, The flat portions 71f and 72f of the first shutter 71 and the second shutter 72 overlap each other (state “E” in FIG. 8 or FIG. 5). When the front door 101 is finally completely closed, the first shutter 71 rotates around 180 °.

  On the other hand, when the front door 101 is opened, the opening / closing operation member 202 of the apparatus main body 100 operates in the reverse direction, and the drum shutter 70 (71, 72) operates in the reverse direction to the above by the spring force of the shutter return spring 73. When the front door 101 is fully opened, the drum shutter 70 (71, 72) completely covers the exposed portion 76 (state shown in FIG. 3).

  As described above, according to the present embodiment, the exposed portion 76 of the photosensitive drum 1 is opened and closed by the drum shutter 70 (71, 72) operated by the drum shutter opening / closing mechanism provided in the apparatus main body.

(Drum shutter opening / closing by drum shutter opening / closing mechanism)
Next, the drum shutter opening / closing mechanism constituting the characteristic part of the present invention will be described with reference to FIGS.

  As described above, the process cartridge 7 (7a, 7b, 7c, 7d) attached to the image forming apparatus main body 100 has a drum shutter 70 (70a, 70a, 70a) that can be opened and closed to protect the exposed portion 76 of the photosensitive drum 1. 70b, 70c, 70d). The drum shutter 70 is opened and closed by a drum shutter opening / closing mechanism. In this embodiment, the drum shutter opening / closing mechanism includes a link unit 110 that operates in conjunction with an opening / closing operation of an opening / closing door (front door) 101 provided in the image forming apparatus main body 100, and a rack that is operated by the link unit 110. It comprises a means 120 and a shutter opening / closing means 200 operated by the rack means 120.

  According to this embodiment, as shown in FIGS. 9 and 10, the opening / closing door 101 and the electrostatic transfer device 5 are swingably attached to the apparatus main body 100 by the support shafts 102 and 103 at the lower ends thereof. Yes. On the other hand, the upper ends of the opening / closing door 101 and the electrostatic transfer device 5 are connected at both ends by connecting links 106 attached to the opening / closing door 101 and the electrostatic transfer device 5 by pivots 104 and 105, respectively. With this configuration, a four-bar link mechanism is formed between the apparatus main body 100, the opening / closing door 101, the electrostatic transfer apparatus 5, and the connecting link 106.

  With the above configuration, by closing the opening / closing door 101 at a predetermined position, the electrostatic transfer apparatus 5 has each process cartridge 7 (7a, 7b, 7c, 7d) mounted on the apparatus main body 100 as shown in FIG. It is positioned at a predetermined position with respect to the formed image forming station. Further, by opening the door 101, the electrostatic transfer device 5 is moved to a position away from the image forming station of the apparatus main body 100 as shown in FIG. 9, and each process cartridge 7 (7a, 7b, 7c) is moved. 7d), the right side surface portion is exposed to the outside in FIG.

  According to the present embodiment, there is provided a link mechanism as a drum shutter opening / closing mechanism provided on the apparatus main body side, which operates in conjunction with such opening / closing operation of the opening / closing door 101. In the present embodiment, as described above, the link mechanism includes the link means 110 that rotates in conjunction with the door 101, the rack means 120 that converts the rotational force of the link means 110 into the vertical direction, In order to transmit the force of the rack means 120 to the drum shutter 70 and to open and close the drum shutter 70, the shutter means 200 is provided corresponding to each image forming station.

  That is, according to the present embodiment, the drum shutter 70 that protects the exposed portion 76 of the photosensitive drum 1 (1a, 1b, 1c, 1d) is opened and closed by the link means 110, the rack means 120, and the shutter opening / closing means 200. The

  First, the link means 110 will be described.

According to the present embodiment, the link means 110 includes a first cam 111 that is integrally attached to the support shaft 103 of the electrostatic transfer device 5 and rotates in order to convert the rotational force of the door 101 into a vertical force. And a second cam 112 oscillated by the first cam 111. The second cam 112 is swingably attached to the apparatus main body 100 with a pin 113.

FIG. 9 shows a state before the door 101 is fully opened or fully closed, that is, approximately half of the apparatus main body 100 is opened, as will be described in detail later. In this state, the protrusion 112a provided on one end side of the second cam 112 that is separated from the pin 113 is fitted into the recess 111a formed on the peripheral surface of the first cam 111, and this state is maintained. . Further, a long hole 112b is formed on the opposite side of the projection 113a with respect to the pin 113 of the second cam 112, and a pin 114 provided at the lower end of the rack means 120, which will be described in detail later, is inserted. Yes.

  In this embodiment, the rack means 120 extends in the vertical direction along a plurality of image forming stations arranged in parallel in the vertical direction. The rack means 120 has an elongated bottom plate 120a and a side plate 120b bent at a right angle to the bottom plate 120a, and is an angle member having an L-shaped cross section.

  Accordingly, the rack members 120a and 120b are disposed to be inclined in the same direction as the process cartridge 7 (7a, 7b, 7c, 7d) mounted on the apparatus main body 100. In the present embodiment, support plates 121 are integrally provided at two locations along the longitudinal direction of the bottom plate 120a. A long groove 122 is formed in the support plate 121 along the longitudinal direction of the rack means 120 and is movably attached to the apparatus main body 100 by a support pin 123.

The rack means 120 has a function of converting the rotational force transmitted by the open / close door 101 and the first and second cams 111 and 112 into a longitudinal force and transmitting it to the four-color image forming station.

  Next, the shutter opening / closing means 200 for transmitting the force from the rack means 120 to the drum shutter 70 will be described with reference to FIGS. 12 is a view of the shutter opening / closing means 200 as viewed from the inside of the apparatus main body, and FIG. 13 is a perspective view of the shutter opening / closing means and the end of the process cartridge as viewed from the apparatus main body opening side.

  12 and 13, in this embodiment, the shutter opening / closing means 200 has a base member 201 attached to the apparatus main body 100 with screws (not shown) or the like. An opening / closing operation member 202 is swingably attached to the base member 201 with a pivot 203. The opening / closing operation member 202 is an elongated arm member, and one end 202 a of the arm member 202 extends toward the drum shutter 70. In the present embodiment, one end 202 a of the arm member 202 extends in the direction of a pin 71 c as an open / close operated member provided in the first shutter 71. As will be described in detail later, the arm member 202 rotates by a force in the direction F from the rack means 120 (FIG. 3), and operates the shutter 71 by pressing the pin 71c of the shutter 71.

  Further, the arm member 202 is integrally provided with a projecting portion 204 that performs a cam action, and can be engaged with a cam member 117 provided on the bottom plate 115 of the rack means 120.

  The arm member 202 is urged clockwise in FIG. 12 by a torsion coil spring 205 as an urging member disposed around the pivot 203, and the home position indicated by a two-dot chain line, that is, the drum shutter 70 is a photosensitive member. The drum 1 is configured so as to cover the exposed portion.

  Next, an operation mode of the shutter opening / closing means 200 according to the present embodiment having the above-described configuration will be described.

  For easy understanding, the case where the door 101 is closed (FIG. 11) and the case where the door 101 is opened from the state shown in FIG. 9) will be described.

  In the state of FIG. 9, the protrusion 112 a of the second cam 112 is fitted in the recess 111 a of the first cam 111.

  First, with reference to FIG. 11, an operation in the case where the opening / closing door 101 of the image forming apparatus is closed after the cartridge 7 is mounted on the apparatus main body 100 will be described. The state of the door 101 shown in FIG. 11 is the same as that in FIG.

  When the door 101 is swung counterclockwise (arrow A direction) in FIG. 11 in order to close the door 101, the electrostatic transfer device 5 is also swung counterclockwise. The first cam 111 also rotates counterclockwise (arrow B direction).

  As a result, the protrusion 111 c formed on the downstream side in the rotation direction of the recess 111 a of the first cam 111 comes into contact with the protrusion 112 a of the second cam 112. Further, when the first cam 111 rotates, the second cam 112 rotates clockwise (in the direction of arrow C) around the pin 113.

  The clockwise rotation of the second cam 112 pushes up the pin 121 of the rack means 120 fitted in the elongated hole 112b of the second cam 112, thereby moving the rack means 120 upward (arrow D direction).

  Due to the upward movement of the rack means 120, as shown in FIG. 12, the cam 204 of the arm member 202 rides on the protruding portion 124 of the rack means 120, and the arm member 202 is counteracted in FIG. Rotate clockwise (arrow E direction).

  The arm member 202 abuts on the pin 71c of the shutter 71 by this rotational movement, and further rotates the arm member 202 counterclockwise, thereby moving the pin 71c downward. As a result, the drum shutter 70 (71, 72) is opened as shown in FIGS. 5 and 15C, and the exposed portion 76 of the photosensitive drum 1 is exposed. At this time, the transfer belt 11 of the electrostatic transfer device 5 is installed at a predetermined position, and an image forming operation can be performed as shown in FIG.

  Next, with reference to FIG. 9, an operation when opening the door 101 of the image forming apparatus will be described.

  As shown in FIG. 9, the fully-closed open / close door 101 shown in FIG. 1 is moved clockwise (arrow F direction) to open the open / close door 101. The electrostatic transfer device 5 swings in the clockwise direction together with the open / close door 101, whereby the first cam 111 rotates in the clockwise direction (arrow G direction), and the second cam 112 rotates in the counterclockwise direction (arrow H direction). ).

  As a result, as shown in FIG. 9, the protrusion 112 a of the second cam 112 is fitted into the recess 111 a of the first cam 111.

  Further, as the first cam 111 rotates, the projection 112a of the second cam 112 contacts the cam 111b of the first cam 111 and rotates counterclockwise around the pin 113 of the second cam 112. .

  By the counterclockwise rotation of the second cam 112, the rack means 120 moves downward (arrow I direction) by pushing down the pin 121 of the rack means 120 fitted in the elongated hole 112b of the second cam 112. .

  Due to the downward movement of the rack means 120, as shown in FIG. 14, the cam 204 of the arm member 202 riding on the protrusion 124 of the rack means 120 is disengaged from the protrusion 124 of the rack means 120. Thus, by the force of the spring 205 attached to the arm member 202, the arm member 202 is moved upward from the protruding portion 124, that is, the arm member 202 is centered on the shaft 203 in FIG. (J direction).

  The arm member 202 releases the force that biases the pin 71c of the shutter 71 downward (F direction in FIG. 3) by this rotational movement. As a result, the drum shutter 70 (71, 72) is closed by the biasing force of the return spring 73 and covers the exposed portion 76 of the photosensitive drum 1 as shown in FIGS.

  According to this embodiment, the position of the protrusion 124 of the rack means 120 is changed between the image forming stations, that is, for each process cartridge 7 (7a, 7b, 7c, 7d) mounted on the apparatus main body 100. Thus, the opening / closing timing of the drum shutter 70 can be changed. For example, when it is desired to open the drum shutter 70 at a timing earlier than that of the other image forming stations, the position of the protrusion 124 of the rack unit 120 may be shifted upward from the other image forming stations. If you want to open at a later timing, you can do the reverse.

  As described above, by operating the position of the protrusion 124 on the rack means 120, the opening / closing timing of the drum shutter 70 at each station can be changed.

  Therefore, for example, when opening the door 101, the drum shutter 70 is sequentially closed from the uppermost image forming station to the lower image forming station, and when the door 101 is closed, the lowermost image forming station is started. The drum shutter 70 can be set to open sequentially to the upper image forming station.

  When the door 101 is opened, the drum shutter 70a of the process cartridge 7a attached to the lowermost image forming station is replaced with the drum shutters 70b, 70c of the process cartridges 7b, 7c, 7d attached to the other image forming stations. When closing the door 101 later than 70d and closing the door 101, the drum shutter 70a of the process cartridge 7a attached to the lowermost image forming station is replaced with the drum shutter 70b of the process cartridges 7b, 7c, 7d attached to the other image forming stations. It can be set to open earlier than 70c and 70d. At this time, for example, when opening the opening / closing door 101, all the drum shutters 70b, 70c and 70d other than the lowermost image forming station are simultaneously closed, and then the drum shutter 70a of the lowermost image forming station is closed. When closing the door 101, it is possible to set so that only the bottom station is opened first, and then all the drum shutters 70b, 70c, 70d other than the bottom image forming station are opened simultaneously. .

  With the above configuration, the exposure amount of the photosensitive drum 1 (1a, 1b, 1c, 1d) of each image forming station when the opening / closing door 101 of the image forming apparatus is opened can be minimized.

  Further, according to the present embodiment, the drum shutter 70 can be closed even if the process cartridge 7 is taken out with the opening / closing door 101 being opened to the minimum necessary level so that the process cartridge 7 can be taken out. The process cartridge 7 can be taken out without fear.

  In the above-described embodiment, the drum shutter 70 is described as including two drum shutters, that is, the first shutter 71 and the second shutter 72. However, the drum shutter 70 includes the single shutter 71. Also good.

Example 2
Another embodiment of the image forming apparatus according to the present invention will be described.

  Also in this embodiment, the image forming apparatus is the same as the color electrophotographic image forming apparatus described in Embodiment 1 with reference to FIG. 1, and the description of the configuration and operation will not be repeated.

  Therefore, the shutter opening / closing mechanism constituting the characteristic part of the present embodiment will be described with reference to FIGS.

  Also in the image forming apparatus of the present embodiment, as in the first embodiment, the process cartridge 7 (7a, 7b, 7c, 7d) mounted on the apparatus main body 100 has the photosensitive drum 1 (1a, 1b, 1c,. An openable / closable drum shutter 70 (70a, 70b, 70c, 70d) for the purpose of protection 1d) is provided.

  In the present embodiment, the drum shutter 70 is described as being composed of two drum shutters, that is, the first shutter 71 and the second shutter 72, as in the first embodiment. You may do.

  According to the present embodiment, the drum shutter 70a of the lowermost process cartridge 7a and the drum shutters 70b, 70c, 70d of the remaining process cartridges 7b, 7c, 7d are performed by different link mechanisms. Different from the first embodiment.

  That is, according to the present embodiment, the opening / closing action of the drum shutters 70b, 70c, and 70d is performed by the link mechanism including the link means 110, the rack means 120, and the shutter opening / closing means 200, as in the first embodiment. However, the opening / closing action of the lowermost drum shutter 70a is performed by a link mechanism different from the link mechanism of the first embodiment.

  Regarding the link mechanism of the drum shutters 70b, 70c, and 70d that is the same as that of the first embodiment, the members having the same functions are denoted by the same reference numerals, and the configuration of the link means 110, the rack means 120, and the shutter opening / closing means 200 is provided. The detailed description of the operation uses the description of the first embodiment.

  Next, the link mechanism for the lowermost drum shutter 70a, that is, the link means 110A and the shutter opening / closing means 200A will be described.

  According to this embodiment, the link means 110A has the operating piece member 115 formed integrally with the first cam 111 constituting the link means 110 acting on the drum shutters 70b, 70c, 70d. In FIG. 16 to FIG. 18, the operating piece member 115 is formed on the front side of the drawing with respect to the cam 111 b and the second cam 112 of the first cam 111. Therefore, the operation piece member 115 does not interfere with the operation of the second cam 112 by rotating.

  The shutter opening / closing means 200A for the lowermost drum shutter 70a has the same configuration as the shutter opening / closing means 200 described in the first embodiment for the other drum shutters 7b, 7c, 7d. However, unlike the shutter opening / closing means 200, the shutter opening / closing means 200 </ b> A is not operated by the rack means 120, and therefore the protrusion 204 is not provided for the opening / closing operation member, that is, the arm member 202. . Instead, the actuated arm 210 is provided integrally.

  Similarly to the first embodiment, the arm member 202 is biased counterclockwise (in the direction of arrow N in FIG. 18) about the rotation shaft 203 by a spring 205 that returns the arm member 202 to the home position. Therefore, the actuated arm 210 abuts on the action pin 115 a disposed at the tip of the actuating piece member 115 of the first cam 111. In this embodiment, the surface 211 of the operated arm 210 with which the action pin 115a abuts is configured by first, second, and third cam surfaces 211a, 211b, and 211c.

  In the present embodiment, the opening operation of the drum shutters 70b, 70c, and 70d is performed by closing the open / close door 101 of the image forming apparatus as described with reference to FIG.

  In FIG. 16, when the door 101 is moved in the counterclockwise direction (arrow A direction) in order to close the door 101, the electrostatic transfer device 5 also swings in the counterclockwise direction. The first cam 111 also rotates counterclockwise (arrow B direction).

  Thereafter, as in the first embodiment, when the first cam 111 rotates, the second cam 112 rotates clockwise around the pin 113, and the rack means 120 moves upward (in the direction of arrow D). Move.

  By the upward movement of the rack means 120, the drum shutters 70b, 70c, 70d are opened as shown in FIGS. 5 and 15C, and the photosensitive drums 1b, 1c, 1d of the process cartridges 7b, 7c, 7d are opened. The exposed portion 76 is exposed. At this time, the transfer belt 11 of the electrostatic transfer device 5 is installed at a predetermined position, and an image forming operation can be performed as shown in FIG.

  On the other hand, the opening operation of the drum shutter 70a is also performed by closing the opening / closing door 101 of the image forming apparatus described above.

  That is, in FIGS. 16 and 17, when the door 101 is moved counterclockwise (arrow A direction) to close the door 101, the electrostatic transfer device 5 also swings counterclockwise. Accordingly, the first cam 111 also rotates counterclockwise (arrow B direction).

  As a result, when the first cam 111 rotates, the operating piece member 115 also rotates counterclockwise about the shaft 103, and the action pin 115 a is a curved cam from the cam surfaces 211 c and 211 b of the operated arm 210. Abutting and sliding on the surface 211a, the operated arm 210 is rotated clockwise (in the direction of arrow L). As a result, the actuated arm 210 contacts the open / close pin 71c of the drum shutter 70a, and moves the pin 71c downward. As a result, the drum shutter 70a (71, 72) is opened as shown in FIGS. 5 and 15C, and the exposed portion 76 of the photosensitive drum 1 is exposed. At this time, the transfer belt 11 of the electrostatic transfer device 5 is installed at a predetermined position, and an image forming operation can be performed as shown in FIG.

  Next, an operation when the opening / closing door 101 of the image forming apparatus is opened will be described.

  When the open / close door 101 is opened by moving the fully closed open / close door 101 shown in FIG. 1 in the clockwise direction (the direction opposite to the arrow A) in FIG. Swings clockwise. Accordingly, as in the first embodiment, the first cam 111 rotates in the clockwise direction (the direction opposite to the arrow B), and the second cam 112 rotates in the counterclockwise direction (the direction opposite to the arrow C). .

  As a result, the rack means 120 moves downward (in the direction opposite to the arrow D) in the same manner as in the first embodiment. Due to the downward movement of the rack means 120, as shown in FIG. 14, the cam 204 of the arm member 202 riding on the protrusion 124 of the rack means 120 is disengaged from the protrusion 124 of the rack means 120. Thus, by the force of the spring 205 attached to the arm member 202, the arm member 202 is moved upward from the protruding portion 124, that is, the arm member 202 is centered on the shaft 203 in FIG. (J direction).

  The arm member 202 releases the force that biases the pin 71c of the drum shutters 70b, 70c, and 70d downward by this rotational movement. As a result, the drum shutters 70b, 70c, and 70d are closed by the urging force of the return spring 73 to cover the exposed portion 76 of the photosensitive drum 1, as shown in FIGS.

  Also in the present embodiment, as in the first embodiment, the position of the protrusion 124 of the rack unit 120 is set between the image forming stations, that is, for each process cartridge 7b, 7c, 7d mounted on the apparatus main body 100. By changing the timing, the opening / closing timing of the drum shutter 70 can be changed with each other, or the same.

  On the other hand, the drum shutter 70a of the lowermost process cartridge 7a operates as the first cam 111 rotates in the clockwise direction (arrow M direction) as the opening / closing door 101 opens, as shown in FIG. The single member 115 also rotates clockwise about the shaft 103, and the pressing force of the shutter opening / closing means 200A on the operated arm 210 is released.

  As a result, the operated arm 210 and the arm member 202 of the shutter opening / closing means 200A are rotated counterclockwise (arrow N direction) by the force of the return spring 205 in FIG. At this time, in order to allow rotation of the actuated arm 210, the action pin 115a of the actuating member 115 contacts the curved cam surface 211a of the actuated arm 210 to the inclined cam surface 211b and then the cam surface 211c. Configured to engage.

  Therefore, the action pin 115a comes into contact with the cam surfaces 211b and 211c from the curved cam surface 211a of the operated arm 210, and rotates the operated arm 210 counterclockwise (arrow N direction). As a result, the operated arm 210 and the arm member 202 rotate by a predetermined angle in the counterclockwise direction to the home position and stop.

  The arm member 202 releases the downward bias of the drum shutter 70a with respect to the pin 71c by this rotational movement. As a result, the drum shutter 70a (71, 72) is closed and covers the exposed portion 76 of the photosensitive drum 1, as shown in FIGS.

  According to the present embodiment, by changing the curved surface profile of the cam surface 211a of the operated arm 210, the drum shutter 70a is minimized so as not to interfere with the open / close door 101 and to minimize the exposure amount of the photosensitive drum 1a. Can be opened earlier than other stations.

  Also in the present embodiment, it is possible to achieve the same effect as that of the first embodiment.

  That is, by operating the position of the protrusion 124 on the rack means 120 as described above, the opening / closing timing of the drum shutters 70b, 70c, 70d of the process cartridges 7b, 7c, 7d can be changed.

  Thus, for example, when opening the door 101, the drum shutter 70 is sequentially closed from the uppermost image forming station, and when closing the door 101, the drum shutter 70 is sequentially opened from the lowermost image forming station. Can be set to

  When the door 101 is opened, the drum shutter 70a of the process cartridge 7a attached to the lowermost image forming station is replaced with the drum shutters 70b, 70c of the process cartridges 7b, 7c, 7d attached to the other image forming stations. When closing the door 101 later than 70d and closing the door 101, the drum shutter 70a of the process cartridge 7a attached to the lowermost image forming station is replaced with the drum shutter 70b of the process cartridges 7b, 7c and 7d attached to the other image forming stations. It can be set to open earlier than 70c and 70d. At this time, for example, when opening the opening / closing door 101, all the drum shutters 70b, 70c and 70d other than the lowermost image forming station are simultaneously closed, and then the drum shutter 70a of the lowermost image forming station is closed. When closing the door 101, it is possible to set so that only the bottom station is opened first, and then all the drum shutters 70b, 70c, 70d other than the bottom image forming station are opened simultaneously. .

  With the above configuration, the exposure amount of the photosensitive drum 1 (1a, 1b, 1c, 1d) at each station when the opening / closing door 101 of the image forming apparatus is opened can be minimized, and the opening / closing door 101 can be used as a process cartridge. Even if the process cartridge 7 is taken out with the minimum necessary amount 7 can be taken out, the drum shutter 70 can be closed, so that the process cartridge 7 can be taken out without fear of damaging the drum shutter 70.

  In the present embodiment, the drum shutter 70 has been described as including two drum shutters, that is, the first shutter 71 and the second shutter 72, but the drum shutter 70 may be configured by one shutter 71. Good.

1 is a schematic diagram illustrating an overall configuration of an embodiment of an image forming apparatus of the present invention. FIG. 3 is a cross-sectional view of a process cartridge that is detachably attached to the image forming apparatus of the present invention. FIG. 3A is a perspective view of the process cartridge, FIG. 3A is a view as seen from an oblique front of the process cartridge, and FIG. 3B is a view as seen from an obliquely lower side of the process cartridge. 3 is an exploded perspective view for explaining a relationship among an image forming apparatus main body, a process cartridge, an opening / closing door, and an electrostatic transfer apparatus. FIG. It is a perspective view which shows the state which has the drum shutter of a process cartridge in an open position. It is a perspective view of the 1st shutter of a drum shutter. It is a perspective view of the 2nd shutter of a drum shutter. FIGS. 8A and 8B are views for explaining the configuration and operation of an embodiment of a drum shutter, FIG. 8A is a perspective view illustrating the entire configuration of the drum shutter, and FIG. It is a perspective view explaining the structure of an edge part, FIG.8 (c) is a figure for demonstrating the operation | movement aspect of a drum shutter. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. It is a figure for demonstrating the link coupling | bonding of an opening-and-closing door and an electrostatic transfer apparatus. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. FIG. 3 is a perspective view of the shutter opening / closing mechanism and the end of the process cartridge in the image forming apparatus of the present invention as viewed from the apparatus main body opening side . It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. It is a perspective view explaining the opening / closing operation | movement aspect of the drum shutter in the process cartridge of this invention. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention. It is a figure explaining the drum shutter opening / closing mechanism in the image forming apparatus of the present invention.

Explanation of symbols

Pa, Pb, Pc, Pd Image forming station 1 (1a to 1d) Electrophotographic photosensitive drum (image carrier)
2 (2a to 2d) Charging means 3 (3a to 3d) Scanner unit 4 (4a to 4d) Developing means 4A Developing unit 5 Electrostatic transfer device 6 (6a to 6d) Cleaning means 7 (7a to 7d) Process cartridge 11 Static Electrotransfer belt 12 Transfer roller 40 Developing roller (developer carrier)
41 Toner container (developer storage part)
46 Developer container unit 70 Drum shutter 71 First shutter 71c Open / close pin (open / close operated member)
72 Second shutter 73 Biasing member (return spring)
DESCRIPTION OF SYMBOLS 100 Image forming apparatus body 101 Opening / closing door 110 Link means (shutter opening / closing mechanism)
111 First cam 112 Second cam 115 Actuating piece 115a Working pin 117 Cam member 120 Rack means (shutter opening / closing mechanism)
124 Projection 200, 200A Shutter opening / closing means (shutter opening / closing mechanism)
201 Base member 202 Opening / closing operation member (arm member)
204 Protruding portion 205 Biasing member (return spring)
210 Actuated arm

Claims (7)

In an image forming apparatus for forming an image on a recording medium,
(I) a photosensitive member, a shutter for protecting the photosensitive member, a plurality having a closed position covering the photosensitive member, wherein the open photoreceptor Ru exposed position, a shutter which can be taken, and the An image forming station in which the process cartridges are detachably mounted in parallel in the vertical direction;
(Ii) An opening / closing door that opens and closes to attach the process cartridge to the image forming station, and has a center of rotation below the image forming station in the vertical direction. A door that is rotatable about a rotation axis parallel to the longitudinal axis of the process cartridge ;
(Iii) A link mechanism for opening and closing the shutters of the plurality of process cartridges in conjunction with the opening and closing operation of the opening and closing doors, wherein the process cartridge is mounted at a position other than the lowest when the opening and closing doors are opened. A link mechanism for moving the shutter to the closed position earlier than the shutter of the process cartridge mounted at the lowermost position, wherein the open / close door is at an angle at which the process cartridge mounted at a position other than the lowermost position can be taken out. A link mechanism configured to position the shutter in the closed position in the open state;
An image forming apparatus comprising:   The link mechanism is configured to move the shutters of the process cartridges mounted sequentially downward from the process cartridge mounted at the uppermost position to the closed position when the opening / closing door is opened. The image forming apparatus according to claim 1.   2. The image forming apparatus according to claim 1, wherein the link mechanism is configured to simultaneously move the shutter of a process cartridge mounted at a position other than the lowermost position to the closed position. The link mechanism is
Link means that rotates in conjunction with the opening and closing door;
Rack means for converting the force in the rotational direction of the link means into the longitudinal direction;
Shutter opening and closing means arranged to transmit the force of the rack means to each of the shutters to move each of the shutters;
The image forming apparatus according to claim 1, further comprising: The link means includes a first cam that rotates in conjunction with the opening and closing door, and a second cam that is rotated by the first cam,
The rack means extends in the vertical direction along the plurality of image forming stations arranged side by side in the vertical direction, and is provided with an elongated rack member movably provided in the vertical direction, and the rack member. And a cam member for adjusting the operation timing of the shutter opening / closing means to determine the opening / closing timing of the shutter,
The image forming apparatus according to claim 4.   The shutter is engaged with a shutter member that rotates about a rotation axis parallel to the longitudinal axis of the process cartridge, a biasing member that biases the shutter member to the closed position, and the shutter opening / closing means. An opening / closing actuated member that is enabled, and the shutter member is opened by rotating the opening / closing member against the urging force of the urging member by the operation of the shutter opening / closing means. The image forming apparatus according to claim 4, wherein the image forming apparatus is moved to a position.   The image forming apparatus according to claim 1, wherein the image forming station is provided to be inclined with respect to the vertical direction.