JP2008268449A - Process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve usability of an image forming apparatus by making an exposure device easily interchangeable according to its service life. <P>SOLUTION: A process cartridge 200 is provided to be attachable/detachable to the image forming apparatus 1. The process cartridge 200 includes at least a photoreceptor 400 and the exposure device 300 exposing the photoreceptor and both are integrally composed via a frame 220. Furthermore, the exposure device 300 can also be composed to be independently attachable/detachable to/from the image forming apparatus 1. In this case, the exposure device 300 is composed so that a relative position to the photoreceptor 400 can be changed after the attachment to the image forming apparatus 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a process cartridge including an exposure device that exposes a photosensitive member to form a latent image on the photosensitive member, and an image forming apparatus including the process cartridge.

  A photosensitive member (image carrier) charged in advance at a predetermined potential is exposed according to image information to form an electrostatic latent image, and the electrostatic latent image is developed with toner, and a visualized toner image is formed. A light beam that uses a laser diode as a light source is called a polygon mirror as an exposure device used in an image forming device that applies the so-called electrophotographic process. A system in which an electrostatic latent image is formed by scanning an image carrier through a polygon mirror, and light emitting elements configured using light emitting diodes (LEDs) or organic electroluminescence (organic EL) materials are arranged in a line. There is known a method of forming an electrostatic latent image on an image carrier by individually lighting (ON / OFF) each light emitting unit using a light emitting element array.

  In the above-described image forming apparatus, from the viewpoint of facilitating replacement of parts, a photosensitive member, a charger that sets the surface of the photosensitive member to a predetermined potential, and a cleaner that cleans the photosensitive member are integrated into a cartridge. Some devices can be detached from the main body of the device. There is also a cartridge in which a developing device and a toner cartridge are integrated. There are also cartridges in which a photoconductor, a charger, a developing device, and a toner cartridge are integrated.

For example, Patent Document 1 discloses an image forming apparatus in which a plurality of photoreceptors are positioned and attached to a photoreceptor cartridge that can be attached to and detached from the apparatus main body. In this image forming apparatus, the developing means is configured to be detachable with respect to each photoconductor mounted on the photoconductor cartridge, and is positioned at a position corresponding to each of the plurality of photoconductors of the photoconductor cartridge. Writing means (exposure device) is attached.
JP 2003-043776 A

  In these cases, the image forming apparatus having the above-described configuration includes an LSU (Laser Scanning Unit) including a light emitting element such as the LED described above or a polygon mirror, and an exposure apparatus that exposes a photosensitive member to the cartridge. No configuration is presented. However, in the future, it is expected that such an exposure apparatus should be incorporated into a cartridge that can be detached from the main body of the image forming apparatus.

  The present invention provides a technique for making an exposure apparatus also detachable from an image forming apparatus, that is, making an exposure apparatus into a cartridge.

  According to the present invention, there is provided a process cartridge that is detachably provided in an image forming apparatus, and the process cartridge includes at least a photoconductor and an exposure device that exposes the photoconductor, and the photoconductor and the exposure device. The image forming apparatus is configured to be integrated with at least one member in a state where the relative position is adjustable, and to be detachable from the image forming apparatus.

  With this configuration, the process cartridge including the exposure apparatus can be configured to be detachable from the main body of the image forming apparatus. Further, the relative position between the photosensitive member and the exposure device can be adjusted in a state where the process cartridge is removed or in a state where the process cartridge is incorporated in the image forming apparatus. Therefore, the process cartridge can be flexibly replaced according to the lifetime of the exposure apparatus, and an easy-to-use image forming apparatus can be provided.

  Further, according to the present invention, there is provided a process cartridge configured such that the exposure device is positioned above the photoconductor when attached to the image forming apparatus.

  With this configuration, it is possible to prevent toner that has fallen due to the action of gravity from adhering to the exposure apparatus.

  In addition, according to the present invention, there is provided a process cartridge further including at least one of a charger, a static eliminator, and a cleaner.

  With this configuration, not only the exposure apparatus but also a process cartridge including other members in the print engine can be configured to be detachable from the main body of the image forming apparatus. Therefore, it is possible to provide an easy-to-use image forming apparatus.

  According to the present invention, the distance between the exposure apparatus and the photoconductor is set to a first distance during the exposure operation, and the distance between the exposure apparatus and the photoconductor during the non-printing operation. Is provided at a second distance longer than the first distance.

  With this configuration, it is possible to prevent the exposure apparatus from being contaminated by adhesion of toner or the like, and to secure a gap through which a cleaning member passes when cleaning a light source such as a light emitting element of the exposure apparatus.

  According to the present invention, the exposure apparatus is provided with a process cartridge that does not include an optical lens.

  With this configuration, the light transmission efficiency can be improved.

  Further, according to the present invention, the exposure apparatus is provided with a process cartridge having on the surface an electrical connection portion that receives power from the main body of the image forming apparatus.

  According to this configuration, it is possible to easily secure power supply from the image forming apparatus main body of the exposure apparatus.

  According to the present invention, there is provided a process cartridge further comprising a positioning member that is supported at both ends of the photosensitive member, supports the exposure device, and biases the exposure device to the side away from the photosensitive member. Is.

  According to this configuration, the exposure apparatus can be further configured to be detachable from the process cartridge.

  According to the invention, the one member is constituted by a frame on which the exposure device is arranged and supporting a rotation shaft of the photosensitive member, and is provided on a main body of the image forming apparatus. An exposure apparatus that can be attached to the image forming apparatus by engaging the frame with a rotating member that is relatively rotatably attached is provided.

  With this configuration, the process cartridge can be easily detached from the main body of the image forming apparatus, and the usability of the image forming apparatus can be further improved.

  Further, according to the present invention, an exposure apparatus is provided that is detachably provided in the image forming apparatus and exposes a photosensitive member of the image forming apparatus, and the exposure apparatus is configured to expose the exposure apparatus when the exposure apparatus is attached to the image forming apparatus. An exposure apparatus is provided that is configured to be held at a predetermined position relative to the photosensitive member while resisting the urging force of a urging member that urges the device away from the photosensitive member. .

  With this configuration, the exposure apparatus can be configured to be easily detachable from the main body of the image forming apparatus. Therefore, the exposure apparatus can be flexibly replaced according to the lifetime of the exposure apparatus, and an easy-to-use image forming apparatus can be provided.

  The above-described image forming apparatus using the process cartridge and the exposure apparatus of the present invention is convenient for the user and easy for the service person to perform maintenance and inspection.

  According to the present invention, the exposure apparatus alone or the process cartridge including the exposure apparatus can be configured to be detachable from the main body of the image forming apparatus. Therefore, the exposure apparatus or the process cartridge can be flexibly replaced according to the lifetime of the exposure apparatus, and an easy-to-use image forming apparatus can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Overview of the operation of the image forming apparatus)
First, an outline of an image forming process of an image forming apparatus to which an electrophotographic process is applied will be briefly described with reference to FIG. FIG. 1 is a conceptual diagram of main parts related to an image forming process of an image forming apparatus, and forms a predetermined image on a recording sheet as a transfer material. The transfer material on which an image is formed includes recording media such as plain paper, OHP sheet, coated paper, and recycled paper.

  In the example of FIG. 1, the surface potential of the image carrier (photosensitive member) is set to −650 V (charged potential VO) using a charger, and the exposure unit (exposure device) is used to correspond to the image forming portion. A part of the image carrier to be exposed is exposed, and an electrostatic latent image corresponding to the printed portion is generated on the image carrier. The potential of this part (exposure potential VL) is set to -50V. Further, a developing bias potential for developing the latent image in the developing unit (voltage generated between the image carrier and the developing unit when the electrostatic latent image is visualized using the developer) VB is set to −250V. Is set, the toner moves from the developing unit based on the potential difference between the exposure potential VL and the developing bias potential VB, develops the electrostatic latent image, and generates a toner image. By the transfer unit, the toner image on the image carrier is transferred to the recording paper conveyed from the paper cassette, and the transferred image is fixed on the recording paper by the fixing roller and the heating roller to form an image.

  In FIG. 1, a static eliminator is shown in order to eliminate unnecessary charging on the image carrier. The static eliminator is disposed in front of the charger and is generally provided in the image forming apparatus. However, the static eliminator can be disposed between the developing unit and the transfer unit, and between the transfer unit and the cleaning unit.

(First embodiment)
FIG. 2 is a perspective view of the image forming apparatus 1 according to the first embodiment of the present invention. The image forming apparatus 1 includes a housing 10, a paper cassette 20, a main body frame 30, and an exterior door 40.

  The casing 10 is formed of resin or the like, constitutes an outer frame of the image forming apparatus 1, and stores each member. As will be described later, the housing 10 is formed with a paper discharge unit 50 on which recording paper discharged after printing is placed. The paper cassette 20 is used in a normal image forming apparatus and can be attached to and detached from the housing by a user. The paper cassette 20 includes a plate 21 biased upward by a predetermined spring, and the recording paper R is stored on the plate 21.

  As shown in FIG. 3, at the time of printing on the recording paper R as a transfer material, the recording paper R is carried out of the paper cassette 20 by the action of the paper feed roller 110 that forms a part of the printing engine 900, and is registered by the registration roller 120. The position is regulated, and the print engine main unit 910 including an exposure apparatus 300 described later is passed. After passing through the print engine main unit 910, the recording paper R passes through the pressure roller 140 and the heating roller 150, is transported along the transport direction A indicated by the arrow, and is disposed in the paper discharge unit 50.

  In addition, the image forming apparatus 1 receives various data (character code, drawing command, etc.) from the outside, creates drawing data, a controller including hardware and software for controlling the print engine 900, a liquid crystal display, and the like. It is comprised from an apparatus etc., is exposed visually to a user from a part of housing | casing 10, and is provided with the display part which displays various statuses. Further, the image forming apparatus can be mounted with a cartridge that stores a developer including toner (color material) and a carrier and supplies the developer to a developing unit 500 described later.

  Next, the print engine 900 will be described. The print engine 900 is a mechanism portion that actually performs printing, and starts from feeding of recording paper, and as described later, physical and other functions such as charging and exposure to a photoreceptor, toner adhesion, toner transfer to a recording paper, and fixing. It is the part in charge of the typical printing process itself.

  As shown in FIG. 4, the print engine 900 includes a paper feed roller 110, a registration roller 120, a print engine main unit 910, a pressure roller 140, and a heating roller 150. The paper feed roller 110 is a roller that carries the recording paper R from the paper cassette 20 toward the print engine main unit 910.

  The print engine main unit 910 is a main part of the print engine 900 and is attached to the inside of the housing 10 via the main body frame 30. The print engine main unit 910 mainly corresponds to a part responsible for exposure, development, and image transfer on a transfer material in the image forming process. The main body frame 30 also serves to hold the shape of the housing 10 from the inside.

  The print engine main unit 910 includes an exposure device 300, a photoreceptor 400, a developing unit 500, a transfer roller 130, a charger 600, a charge eliminator 700, and a cleaner 800, and performs an image forming process other than fixing an image on a recording sheet R. Do. The heating roller 150 follows the pressure roller 140, and an image is fixed and formed on the recording paper R by the heating action of the recording paper R by the heating roller 150 and the pressure by the pressure roller 140.

  The registration roller 120 is a member that conveys the recording paper R along the conveyance path A (FIG. 3) to a transfer position on the photosensitive member 400 (FIG. 6). The registration roller 120 temporarily stops the recording sheet R that has been conveyed at that position, prevents skewing of the recording sheet R, and starts driving at a predetermined timing controlled by the controller. Is transported along the transport path. Further, in order to increase the accuracy of the conveyance position and the conveyance speed, one of the registration rollers 120 is preferably constituted by a metal shaft, and the position of the recording paper R is substantially regulated in the conveyance direction of the recording paper R. Yes.

  As described with reference to FIG. 1, the charger 600 applies a predetermined potential (charging potential VO) to the photoconductor 400 according to the control of the controller to charge the photoconductor 400. Then, the exposure unit 400 exposes the photosensitive member 400 based on the drawing data from the controller, and sets the potential of this portion to a predetermined potential (exposure potential VL), thereby generating an electrostatic latent image corresponding to the printed portion. It is generated on the photoreceptor 400.

  In the developing unit 500, when a developing bias potential for developing the latent image (voltage generated between the photosensitive member and the developing unit when the electrostatic latent image is visualized using a developer) VB is set. The toner moves from the developing unit 500 based on the potential difference between the exposure potential VL and the developing bias potential VB, develops the electrostatic latent image, and generates a toner image. Further, the transfer roller 130 transfers the toner image on the image carrier onto the recording paper R conveyed from the paper cassette 20.

  The image transferred from the photoreceptor 400 to the recording paper R is fixed on the recording paper R by the heating action by the heating roller 150 and the pressure by the pressure roller 140, and as a result, a toner image is formed on the recording paper R. The

  A cleaner (cleaning unit) 800 is configured by brush cleaning, and serves as the cleaning unit of FIG. 1 to remove unnecessary toner adhering to the photoreceptor 400. The static eliminator 700 emits static elimination light excluding unnecessary charge remaining on the surface of the photoconductor 400 after the photoconductor 400 is cleaned by the cleaner 800.

  As shown in FIG. 5, the exterior door 40 is pivotable upward, and by opening the exterior door 40, the user can touch the print engine 900 (print engine unit 910) inside the housing 10 and repair it. In addition, parts can be easily replaced.

  Next, the process cartridge 200 according to the present invention will be described with reference to FIGS. As shown in FIGS. 11 and 12, the process cartridge 200 of the present invention is a process cartridge that is detachably provided in the image forming apparatus 1. As shown in FIG. 6, the process cartridge 200 includes at least a photoconductor 400 and an exposure device 300 that exposes the photoconductor. The process cartridge 200 corresponds to the photoconductor 400 and the photoconductor 400 on a one-to-one basis. An exposure apparatus 300 that exposes the body 400 is supported by a single frame 220 and is integrally formed.

  That is, as shown in FIGS. 6 and 7, the rotation shafts at both ends in the longitudinal direction of the photoconductor 400 are supported by the frame 220, and the exposure apparatus 300 is integrally disposed above the frame 220, that is, above the photoconductor 400. ing. As will be described later, the frame 220 includes a protrusion 221 that constitutes an engagement member used for engagement with the main body frame 30, an engagement plate 222, and the like. In this embodiment, as will be described later (FIG. 15), not only the exposure apparatus 300 and the photosensitive member 400 but also the charger 600, the static eliminator 700, and the cleaner 800 are attached to the frame 220. The exposure apparatus 300, the photosensitive member 400, the charger 600, the static eliminator 700, and the cleaner 800 are integrally attached to constitute the process cartridge 200. However, as shown in FIG. 7, the exposure apparatus 300 can be easily detached from the frame 220, and the remaining part from which the exposure apparatus 300 is removed from the process cartridge 200 constitutes the sub-process cartridge 210.

  FIG. 8 is a perspective view of a single exposure apparatus 300, and FIG. 9 is a side view of the exposure apparatus 300. FIG. 10 is a perspective view of the exposure apparatus 300 cut along the line II-II in FIG.

  In the exposure apparatus 300, an exposure head part 310 that emits light for exposing the photosensitive member 400 and a functional part 330 that is used for securing an electrical connection with the outside include a common glass substrate 360 and both ends in the longitudinal direction of the exposure apparatus 300. It is formed integrally through a hinge part 320 (FIG. 9) provided in the part. In the exposure head unit 310, a light emitting element row (not shown) extending in the longitudinal direction (main scanning direction) of the exposure head unit 310 is formed. The light-emitting element array includes a plurality of light-emitting elements (light sources) arranged in a line in the longitudinal direction of the exposure head unit 310, and exposes the opposing photoreceptor 400. As a light emitting element, solid light emitting elements, such as a light emitting diode (LED; Light Emitting Diode) and an organic electroluminescent element (organic EL; Organic Electroluminescence), are mentioned.

  Note that the exposure head unit 310 of the exposure apparatus 300 according to the present embodiment includes a light-emitting element such as an imaging lens (for example, an imaging lens including a plurality of bowl-shaped plastic lenses and a so-called lens array). There is no optical lens that acts optically on the light. The optical lens has a light transmission efficiency of about 6%. In order to irradiate the photosensitive member with strong light, the light emission intensity from the light emitting element must be increased. However, in such a case, the light emission lifetime of the light emitting element, particularly the organic EL element, may be extremely shortened. However, since no optical lens is used in this embodiment, transmission efficiency can be improved and the light emission intensity of the light emitting element can be suppressed, so that the light emission lifetime of the light emitting element can be prevented from being shortened.

  The function unit 330 is supplied with electric power from a power supply unit (not shown) in the main body of the image forming apparatus 1, lighting information (that is, image data) when exposing the photosensitive member 400, and signal lines for controlling the lighting timing of the image data. A substrate 350 provided with a plurality of external terminal connection pads 352 constituting an electrical connection portion that receives the electrical connection portion is disposed on the surface thereof.

  In the present embodiment, the above-described light emitting element (organic electroluminescence element) is formed on the glass substrate 360, and the surface on which the light emitting element is formed faces the photosensitive member 400 (that is, emitted from the light emitting element). The so-called top emission structure in which the emitted light is emitted to the space without passing through the glass substrate 360). Further, the light emitting element is sealed with silicon oxynitride (SiON) having a thickness substantially equal to the size of the light emitting element (diameter if the light emitting element is circular, or side length if the light emitting element is square). The interval between the light emitting element and the surface of the photoreceptor 400 is substantially equal to the sealing thickness. The use of silicon oxynitride for sealing has the following important meaning. Silicon oxynitride, for example, has a higher barrier performance against gases such as oxygen and moisture than silicon oxide, and further adjusts the sputtering atmosphere during formation (for example, the gas partial pressure in the introduced gas is O2 / (O2 + N2) = 0.05), the internal stress of the formed film can be made zero. As a result, no stress in the direction parallel to the glass substrate 360 acts on the organic electroluminescence element (especially its electrode), and the manufacturing yield of the exposure apparatus is dramatically improved.

  In the present embodiment, the circuit for driving the light emitting element is configured by a passive matrix method. The passive matrix method emits light between the regions sandwiched between the row and column electrodes and has a simple configuration. However, the passive matrix method substantially requires time-division driving, and the instantaneous light emission amount of the light emitting element becomes large. . However, according to the configuration of the present embodiment having no imaging lens, the transmission efficiency of the light emitted from the light emitting element is extremely high. Therefore, even if the light emitting element is driven by the passive matrix method, the light emitting element emits a large amount of light. The amount of light is not required.

  When the exposure apparatus 300 is connected to the frame 220, the tab-like connection portions 331 provided at both ends of the functional portion 330 are connected to the flat plate portion 224 of the frame 220 as indicated by dotted arrows in FIG. The tip of the positioning shaft 377 of the positioning member 370 is inserted into the positioning hole 310a of the exposure head 310 (see FIG. 16).

  As shown in FIG. 9, a gap sheet 365 is provided on the lower surface of the common glass substrate 360, that is, the surface facing the photoreceptor 400. The gap sheet 365 generally has a thickness of 20 to 50 μm and is made of a low sliding sheet such as Teflon (registered trademark).

  Although the gap sheet 365 is provided on the lower surface of the exposure head unit 310, the distance between the glass substrate 360 and the photoconductor 400 is extremely short. The substrate 360 may be damaged. Therefore, the force (arrow M) applied from the pressing spring 42 to the exposure head unit 310 needs to be kept small.

On the other hand, in the functional unit 330, it is necessary to ensure a large force (arrow N) from the connector connected to the external terminal connection pad 352 of the substrate 350 in order to ensure electrical connection with the outside. That is, the exposure apparatus 300 is required to vary the optimum external force applied to each part.

  In order to achieve such characteristics, in this embodiment, a configuration is adopted in which the flat plate portion 224 of the frame 220 receives a large force N applied to the functional portion 330 via the connection portion 331. Further, the force N is diverged by the deflection of the hinge part 320 connecting the connection part 331 and the exposure head part 310 so that such a large force N is not transmitted to the exposure head part 310 side.

  Note that in this embodiment, the glass substrate 360 is used as a substrate that supports the light emitting element. However, when there is a problem that the glass substrate 360 is damaged, it is preferable to use a plastic as a substrate on which the light emitting element is formed. Then, the plastic substrate may be arranged with tension applied in the longitudinal direction of the exposure apparatus 300 (z direction shown in FIG. 8). At this time, the distance from the photoreceptor 400 may be regulated by a member that applies tension.

  Next, a method for attaching the process cartridge 200 to the main body of the image forming apparatus 1 will be described with reference to FIGS.

  As shown in FIGS. 2 and 11, a main body frame 30 that forms a part of the main body of the image forming apparatus 1 is provided with a rotating member 31 that is rotatable relative to the main body frame, and thus the main body of the image forming apparatus. Is attached. The rotating member 31 is rotatably attached to a side frame 33 that forms a side surface of the main body frame 30 via a screw 32. The rotation member 31 is provided with a connection terminal 31a, and is electrically connected to the external terminal connection pad 352 of the exposure apparatus 300 when the process cartridge is attached to the image forming apparatus.

  The user moves the process cartridge 200 in the direction of arrow B, contacts the rotating member 31, and further moves in the direction of arrow B. Then, the rotating member 31 rotates about the screw 32 in the direction of arrow C. Thereafter, when the user further pushes in the process cartridge 200 while following the rotation operation of the rotating member 31 in the direction of arrow C, the protrusion 221 formed on the side surface of the frame 220 is a slot formed in the side frame 33. Enter 34. Similarly, the engaging claws 222 a of the engaging plate 222 formed on the side surface of the frame 220 engage with the side window 35 formed on the side frame 33. Through such a procedure, as shown in FIG. 12, the process cartridge 200 is attached to the main body frame 30 and eventually to the main body of the image forming apparatus 1. In addition, the process cartridge 200 can be detached from the main body frame 30 and thus the main body of the image forming apparatus 1 by performing a procedure operation reverse to the above procedure. Accordingly, the process cartridge 200 can be easily attached to and detached from the image forming apparatus 1.

  At the same time, since the connection terminal 31a of the rotating member 31 is electrically connected to the external terminal connection pad 352 of the exposure apparatus 300, power supply to the exposure apparatus 300 can be easily ensured.

  FIG. 13 is a view showing a state in which the exposure apparatus 300 is detached from the process cartridge 200 and, consequently, the main body of the image forming apparatus 1. Thus, in the present embodiment, it can also be understood that the exposure apparatus 300 is detachably provided in the image forming apparatus 1. FIG. 14 is a view showing a state where the sub-process cartridge 210 is removed after only the exposure apparatus 300 is removed as shown in FIG.

  As shown in FIG. 13, the exposure apparatus 300 is configured to be detachable from the main body of the image forming apparatus 1 by itself. Such a configuration will be described with reference to FIGS.

  FIG. 15 is a perspective view showing a state in which the process cartridge 200 is cut along the line II in FIG. As shown in FIG. 15, the process cartridge 200 is configured by integrally attaching an exposure device 300, a photoreceptor 400, a charger 600, and a cleaner 800 to a frame 220. Although the static eliminator 700 is omitted in FIG. 15, the static eliminator 700 can also be attached to the frame 220. In addition, at least one of the charger 600, the static eliminator 600, and the cleaner 800 can be configured to be included in the process cartridge 200. The cleaner 800 is in contact with the surface of the photoreceptor 400, and a cleaning blade 810 that wipes off the toner adhering to the surface, and a waste toner transport as a waste toner transport unit that transports the wiped toner to a waste toner storage container (not shown). An auger 820 is provided.

  In this embodiment, a positioning member 370 is provided that is supported at both ends of the photoconductor 400 (see FIG. 17), supports the exposure apparatus 300, and biases the exposure apparatus 300 away from the photoconductor 400. Yes. The positioning member 370 is mounted on the housing 371, a box-shaped housing 371 formed from a resin case, a pair of rotating rollers 373 housed in the housing 371, a positioning shaft 377 formed integrally with the housing 371. And a biasing spring 375 as a biasing member.

  The rotating roller 373 is rotatably housed in the housing 371, is in contact with the photoreceptor 400, and rotates with the rotation of the photoreceptor 400. Further, the tip of the positioning shaft 377 is formed in a tapered shape, and can be inserted into a positioning hole 310 a formed in the exposure head portion 310 of the exposure apparatus 300.

  As shown in FIGS. 16 and 17, when the user attaches the exposure apparatus 300 to the frame 220 (sub-process cartridge 210), and thus to the main body of the image forming apparatus 1, the positioning hole 310 a of the exposure head unit 310 is inserted into the positioning hole 310 a. Alignment is performed so that the tip of the positioning shaft 377 enters. When the exposure apparatus 300 is pushed toward the frame 220 side against the repulsive force of the urging spring 375 while being aligned, both ends of the exposure head portion 310 are engaged with the engaging claws 223a of the engaging protrusions 223 of the frame 220. Engage. Furthermore, the connection part 331 of the functional part 330 is disposed on the flat plate part 224 of the frame 220. As shown in FIG. 17, the exposure apparatus 300 is attached to the frame 220 while suppressing the repulsive force by the biasing spring 375. FIG. 18 is a cross-sectional view of the vicinity of the print engine main unit 910 of the engine 900 of the image forming apparatus 1 to which the exposure apparatus 300 is thus attached.

  In the present embodiment, only the exposure apparatus 300 or the process cartridge 200 including the exposure apparatus 300 is configured to be easily detachable from the main body of the image forming apparatus 1. Accordingly, the user can easily replace the exposure apparatus or the cartridge made up of the exposure apparatus and other components in accordance with the life of the light emitting light source, and the usability and maintainability of the image forming apparatus can be improved. .

  In the present embodiment, in the process cartridge 200, the photosensitive member 400 and the exposure apparatus 300 are integrated with each other via the frame 220, which is at least one member, with the relative position adjustable. That is, the relative positions of the photosensitive member 400 and the exposure apparatus 300 can be adjusted by the action of the engagement protrusion 223 of the frame 220 of the process cartridge 200 itself and the positioning member 370. Further, the relative position of the photosensitive member 400 and the exposure apparatus 300 can be adjusted also by the action of the pressing spring 42 attached to the exterior door 40 which is a member outside the process cartridge 200. Therefore, it is possible to flexibly replace the process cartridge 200 according to the lifetime of the exposure apparatus 300, and to easily adjust the relative position between the exposure apparatus 300 and the photosensitive member 400.

  In the present embodiment, the exposure apparatus 300 is configured to be positioned above the photoreceptor 400 when attached to the image forming apparatus 1. Accordingly, the possibility that the exposure apparatus 300 is contaminated due to toner adhesion or the like is reduced, and the exposure apparatus 300 can be easily attached and detached. In other words, this configuration may be rephrased as the one in which the exposure apparatus 300 is arranged at the position to be accessed first when the user can access the process cartridge.

  In the present embodiment, when the exposure apparatus 300 is attached to the image forming apparatus 1, the exposure apparatus 300 counters the biasing force of the biasing spring 375 that biases the exposure apparatus itself toward the side away from the photoreceptor 400. The photosensitive member 400 is held at a predetermined position. Such holding is achieved by engaging both end portions of the exposure head portion 310 of the exposure apparatus 300 with the engaging claws 223 a of the engaging protrusions 223 in the frame 220. Accordingly, the attachment / detachment of the exposure apparatus 300 to / from the image forming apparatus 1 can be easily achieved. Further, even when the process cartridge 200 is detached from the main body of the image forming apparatus due to the action of the urging spring 375, the exposure head 33 and the photosensitive member 400 are separated as much as possible, and scratches due to an impact on the photosensitive member 400, etc. Scratches can be prevented from occurring.

  When the exterior door 40 is closed after the exposure apparatus 300 is attached to the frame 220, the pressing springs 42 attached to the exterior door 40 press both ends of the exposure head part 310 of the exposure apparatus 300. Since the weight of the pressing spring 42 is larger than the weight of the biasing spring 375, the exterior lid 40 is closed in the exposure head unit 310 and the exposure apparatus 300 that are retracted (departed) from the photosensitive member 400 by the biasing spring 375. And the distance between the photosensitive member 400 and the exposure apparatus 300 is maintained at a predetermined distance in order to approach the photosensitive member 400 via the gap sheets 365 (FIG. 9) disposed at both ends in the longitudinal direction of the exposure head unit 310. Can do.

  During the exposure operation by the exposure apparatus 300, the distance between the exposure apparatus 300 and the photoconductor 400 is set to the first distance, and during the non-printing operation, the distance between the exposure apparatus 300 and the photoconductor 400 is the first distance. A mechanism for adjusting the degree of compression of the biasing spring 375 may be provided so that the second distance is set to be longer than the first distance. With such a mechanism, it is possible to prevent the exposure apparatus 300 from being contaminated by toner adhesion or the like, and to secure a gap through which the cleaning member passes when cleaning the light emitting elements of the exposure apparatus 300.

(Second Embodiment)
FIG. 19 is a perspective view of the image forming apparatus 1 according to the second embodiment of the present invention. The image forming apparatus 1 has substantially the same configuration as that of the first embodiment, but in this embodiment, the exposure device for the photosensitive member 400, the exposure head 300A in this embodiment, is disposed on the inner surface of the exterior door 40. An exposure head positioning device 380 that determines a specific position is provided.

  20 and 21, the lower surface (inner surface) of the exterior door 40, that is, between the main body of the image forming apparatus 1 and the positioning apparatus main body 381 constituting the main part of the exposure head positioning apparatus 380, is provided. A spring 382 as an urging member is provided, and an exposure head positioning device 380 is constituted by the positioning device main body 381 and the spring 382. As shown in FIG. 22, the springs 382 are attached to protrusions 383 provided at both ends in the longitudinal direction of the casing 384 of the positioning device main body 381, and bias the positioning device main body 381 toward the photoconductor 400.

  The exposure head 300A corresponds to the exposure apparatus 300 in the first embodiment, and is held in the housing 384. Due to the action of the spring 382, the positioning device main body 381 is biased toward the photoconductor 400, and the exposure head 300A is also indirectly biased toward the photoconductor 400.

  As shown in FIG. 22, in the longitudinal direction of the positioning device main body 381, a positioning having a configuration equivalent to that of the positioning member 370 of the first embodiment is provided on the outer side of the protrusion 383 and on the lower side of the positioning device main body 381. A member 370 is disposed. As shown in FIGS. 23 and 24, the positioning member 370 is formed integrally with a housing 371 formed of a resin case, a pair of rotating rollers 373 and 373 housed in the housing 371, and the housing 371. Positioning shaft 377. In the present embodiment, unlike the first embodiment, the biasing spring 375 is not provided.

  The pair of rotating rollers 373 and 373 constitutes a rotating body that abuts on the photosensitive member 400 and rotates following the photosensitive member as the photosensitive member rotates. The rotating rollers 373 are arranged so that the longitudinal direction thereof is parallel to the longitudinal direction of the photosensitive member 400, and the rotating rollers 373 are arranged in the rotating direction of the photosensitive member 400. A rotating shaft (not shown) of the rotating roller 373 is supported by the housing 371, so that the rotating roller 373 is rotatably held by the housing 371.

  The rotating roller 373 is preferably made of a material having low sliding properties such as tetrafluoroethylene or polyphenylene sulfide. Moreover, although it can also comprise with a metal from a viewpoint of shape maintenance property and durability, in this case, it is preferable to form the membrane | film | coat by the resin mentioned above on the surface. In this embodiment, the rotating body that contacts the photosensitive member 400 is configured by the pair of rotating rollers 373 and 373. However, a specific example of the rotating body is not limited to the pair of rotating rollers 373 and 373, and the size thereof is not limited. The shape, the number, and the like are arbitrary, and any shape may be used as long as it is configured to be rotatable so that friction with the photoreceptor 400 is reduced.

  The box-shaped housing 371 is formed of a resin case or the like, and functions as a rotating body holding member that holds the pair of rotating rollers 373 and 373 as rotating bodies in a rotatable state as described above. The shape of the housing 371 is not particularly limited.

  As shown in FIGS. 25 and 26, a part of the positioning member 370, that is, the upper surface of the housing 371 and the positioning shaft 377 are exposed from the frame 220 so as to face the positioning device main body 381. The distal end of the positioning shaft 377 is formed in a tapered shape, and a positioning hole (not shown) provided in the housing 384 of the positioning device main body 381 (into the positioning hole 310a formed in the exposure head portion 310 of the first embodiment). Equivalent).

  As shown in FIG. 27, in a normal state, the urging force (the urging force by the spring 382) F applied to the positioning member 370 from above is directed toward the center of the photoreceptor 400. That is, the urging force F applied from the spring 382 and the positioning device main body 381 finally reaches the pair of rotating rollers 373 and 373 of the positioning member 370. The rotating rollers 373 and 373 are in contact with the photosensitive member 400, and the urging forces FA and FB distributed to the rotating rollers 373 are both directed toward the center of the photosensitive member 400, whereby the positioning member 370 is placed on the photosensitive member 400. Arranged stably.

  In the present embodiment, the portion of the exposure head positioning device 380 that contacts the photoconductor 400 is constituted by a rotating body such as a roller 373 and rotates as the photoconductor 400 rotates. Therefore, friction between the exposure head positioning device 380 and the photosensitive member 400 can be reduced, and the life of the exposure head positioning device 380 is ensured and accurate positioning is also possible.

  Next, details of the positioning device main body 381 will be described with reference to FIGS. 28 to 31. The outer frame of the positioning member main body 381 includes a housing 384 that houses various members. As shown in FIGS. 22 and 28, a projection for holding a spring 382 (see FIGS. 19 to 22) as an urging member is provided on the upper surface of the housing 384, and the positioning device main body is operated by the action of the spring 382. 381 is always biased downward, that is, toward the photoreceptor 400 side.

  On the other hand, an exposure head 300 </ b> A is disposed on the lower surface of the housing 384 and is disposed to face the photoconductor 400. That is, the housing 384 also functions as an exposure head holding member that holds the exposure head 300A. Usually, the distance of the gap between the exposure head 300A and the photoreceptor 400 is set to about 50 μm.

  The housing 384 houses a position adjustment member that moves the exposure head 300A relative to the photoreceptor 400 in order to adjust the distance between the photoreceptor 400 and the exposure head 300A. In the present embodiment, the position adjusting member includes a screw 385 and an eccentric gear (helical gear) 386. A part of the position adjustment member, more precisely, a part of the eccentric gear 386 is exposed from the housing 384 through the slot 384a and is in contact with the housing 371 of the positioning member 370 (see FIG. 22).

  The user and service person can access the screw 385 from the outside of the housing 384, that is, the screw 385 can be turned as shown by an arrow D in FIG. Is possible. Inside the housing 384, the screw 385 and the eccentric gear 386 are engaged with each other, and the eccentric gear 386 can be rotated and driven in the direction of the arrow E by turning the screw 385 in the direction of the arrow D. is there.

  The eccentric gear 386 includes a gear portion 386 b that meshes with the screw 385, and an abutting portion 386 c that is formed integrally with the gear portion 386 b and abuts against the housing 371. A pair of abutting portions 386c are provided on both surfaces of the gear portion 386b, and stably abut on the upper surface of the housing 371 (see FIG. 25). A circular protrusion 386 a that rotates in a slot 384 b formed in the housing 384 as the eccentric gear 386 rotates is provided on the contact portion 386 c. By restricting the protrusion 386a by the slot 384b, the eccentric gear 386 is stably held at a predetermined position in the housing 384 even if it rotates.

  As shown in FIG. 31, the rotation center X of the gear portion 386b is on the protrusion 386a, and is shifted from the rotation center Y of the contact portion 386c. Accordingly, when the eccentric gear 386 is rotated and driven in the direction of arrow E (FIG. 29), the locus of one point on the outer periphery of the contact portion 386c is as indicated by arrow G. This means that as the screw 385 rotates, the distance between the rotation center X of the gear portion 386b and the contact position with the housing 371 varies. Since the positioning device main body 381 is constantly biased downward by the action of the spring 382, the positioning main body 381 moves up and down by this series of actions. When the eccentric gear 386 rotates in any direction from the state of FIG. 31, the distance between the rotation center X and the contact position with respect to the housing 371 is shortened, and the positioning device main body 381 moves downward. As a result, the distance between the exposure head 300A and the photoreceptor 400 varies, and the positioning of the exposure head 300A is realized.

  With the above-described configuration, the exposure head 300A can be easily adjusted to an optimal position (exposure light focus position) with respect to the photoreceptor 400. In this embodiment, the eccentric gear 386 is used to achieve a gear ratio of about 20: 1, and the eccentric amount and the eccentric angle as described in Patent Document 1 are 1: 1. Compared to the configuration, finer fine adjustment is possible. Further, the use of the eccentric gear 386 makes it difficult to shift the focal position. Furthermore, by connecting a driving motor to the eccentric gear 386, electric fine-tuning autofocus can be realized.

  In the present embodiment, a plurality of rotating rollers 373 and 373 as rotating bodies are provided in the rotating direction of the photosensitive member 400 and abut against the photosensitive member 400. Therefore, the exposure head 300A is stably disposed on the photoreceptor 400 via the housing 384, the position adjustment member, and the positioning member 370. Furthermore, since the positioning members 370 are provided at both ends in the longitudinal direction of the exposure head 300A, the exposure head 300A is more stably disposed on the photoreceptor 400.

  In the present embodiment, the housing 384 (positioning device main body 381) serving as the exposure head holding member is configured separately from the housing 371. In this configuration, the relative position of the housing 384 (positioning device main body 381) with respect to the photosensitive member 400 is changed independently of the positioning member 370 that directly contacts the photosensitive member 400, and consequently, the exposure head 300A and the photosensitive member 400 are aligned. The distance between can be changed. Also, the housing 384 that holds the exposure head 300A is configured separately from the housing 371 that holds the rotating rollers 373 and 373, and the screw 385 and the eccentric gear 386 that constitute the position adjusting member are easily housed in the housing. It becomes possible.

  However, the configuration of the present invention is not limited to such an embodiment. For example, a housing 371 (rotary member holding member) that holds a pair of rotating rollers 373 and 373 and a housing 384 (exposure head holding member) that holds the exposure head 300A are formed of an integral member, and the exposure head 300A is configured as such. The distance between the exposure head 300 </ b> A and the photosensitive member 400 may be changed. Such a configuration is also included in the present invention.

  32 to 34 are diagrams showing another example 370A of the positioning member 370. FIG. In this example, the contact portion 386c of the eccentric gear 386 of the housing 371, that is, the surface 371a that contacts the position adjusting member, is an inclined surface 371a inclined with respect to the surface PP defined by the pair of rotating rollers 373 and 373. Consists of. The surface PP is defined by a surface including a portion where the rotating rollers 373 and 373 come into contact with the photoreceptor 400.

  FIG. 33 is a diagram showing an arrangement state of the photoconductor 400, the positioning member 370A, and the positioning device main body 381 when the positioning member 370A of this example is employed. As shown in this figure, the positioning device main body 381 is not arranged toward the center of the photoreceptor 400 by the action of the inclined surface 371a (FIG. 32) of the housing 371, but the arrangement direction is deviated from the center.

  In this example, as shown in FIG. 34, in a normal state, the pressing force F (the pressing force by the spring 382) F applied to the positioning member 370A from above, that is, from the outside is different from the example of FIG. It doesn't go to the center. That is, the pressing force F applied from the spring 382 and the positioning device main body 381 is the resultant force of the urging forces FA and FB distributed to the respective rotating rollers 373, along F1 toward the center of the photoreceptor 400 and along the inclined surface 371 a. It will be decomposed into two component forces of F2. Such a decomposition action into two component forces with respect to the pressing force F is performed by the inclined surface 371 a of the housing 371.

  The component force F2 is an urging force facing one of the circumferential directions of the photoreceptor 400, and a force in one direction is always applied to the positioning member 370A. In the example of FIG. 27, since there is no such force, the positioning member 370 sometimes becomes unstable on the photoreceptor 400 due to a slight deviation on the tolerance of the member, but in this example, it is more stable. Positioning member 370 </ b> A can be disposed on photoconductor 400. That is, since the positioning members 370 disposed at both ends of the photoconductor 400 are always urged in the same direction (F2) with respect to the photoconductor 400, for example, the frame 220 (see FIG. By arranging a stopper or the like in 25), the exposure head 300A can be arranged more parallel to the rotation axis of the photoconductor 400 than in the example of FIG. That is, an image can be formed at a right angle to a recording medium fed in parallel to the photoreceptor 400.

  Although the biasing force F1 may be generated by pressing the inclined surface 371a of the housing 371 as described above, for example, the inclined surface 371 may be configured by making one diameter of the rotating roller 373 different from the other. A similar effect can be obtained.

  Further, it is desirable that the direction of the urging force F <b> 1 coincides with the rotation direction of the photoreceptor 400. Although the rotating roller 373 is provided to be rotatable with respect to the housing 371, a frictional force is always generated when the rotating roller 373 rotates, so that the positioning member 370 </ b> A is displaced in the rotation direction of the photosensitive member 400 by the rotation of the photosensitive member 400. A force Fx (not shown) to be applied acts. Here, if the urging force F1 acts in the direction opposite to the rotation direction of the photosensitive member 400, a situation in which Fx and the urging force F1 antagonize as a result (for example, a situation in which the rotation of the rotating roller 373 is not smooth). This is because the position of the positioning member 370A becomes unstable when this occurs.

  35 and 36 are diagrams showing another example 370B of the positioning member 370. FIG. In this example, a felt (or sponge) 377 that is a lubricant-impregnated member impregnated with a lubricant (silicon, fluorine dispersion, etc.) is attached to a housing 371, and a blade 376 that wipes off the lubricant. The blade 376 is made of urethane, EPDM (ethylene propylene diene monomer), silicon, or the like. In the positioning member 370B, the lubricant is always supplied to the pair of rotating rollers 373 and 373, and low friction with respect to the photosensitive member 400 can be maintained.

  FIG. 37 is a diagram illustrating a state in which a change in MTF (Modulation Transfer Function) is observed in the positioning device main body 381 when the position of the exposure head 300A is changed. The positioning device main body 381 is fitted into a concave portion 1200 provided in the base 1000, but an urging spring 1100 is provided in the concave portion 1200, and the positioning device main body 381 is moved by the action of the urging spring 1100. Against the opposite wall 1210 (FIG. 38).

  When the observer turns the screw 385 in the direction of arrow H, the eccentric gear 386 is driven and rotated as shown in FIG. 29, and the positioning device body 381 is moved in the direction of arrow I by the action of the wall 1210 and the biasing spring 1100. Move in the direction. 39 and 40 show the results of measuring the MTF at an arbitrary position moved using the camera 1300 provided on the base 1000. FIG. As described above, by using the screw 385 and the eccentric gear 386 as the position adjusting member in the positioning apparatus main body 381, the optimum position of the exposure head 300A can be determined.

  Although various embodiments of the present invention have been described, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art may modify or apply the description based on the description of the specification and well-known techniques. The present invention is intended to be included in the scope for which protection is sought.

  According to the present invention, an exposure apparatus alone or a process cartridge including an exposure apparatus that is detachable from the main body of the image forming apparatus is provided, so that the usability of the image forming apparatus can be improved.

Conceptual diagram showing the operation of the image forming apparatus 1 is a perspective view of an image forming apparatus according to a first embodiment of the present invention. 1 is a side view showing a state in which recording paper is conveyed in the image forming apparatus according to the first embodiment of the present invention. 1 is a side view of an image forming apparatus according to a first embodiment of the present invention. The side view in the state where the exterior door was opened in the image forming device of a 1st embodiment of the present invention. The perspective view of the process cartridge of the 1st Embodiment of this invention The perspective view of the state at the time of disassembling the process cartridge of the 1st Embodiment of this invention into an exposure apparatus and a sub process cartridge The perspective view of the exposure apparatus of the 1st Embodiment of this invention 1 is a side view of an exposure apparatus according to a first embodiment of the present invention. The perspective view of the state which cut | disconnected the exposure apparatus along the II-II line | wire of FIG. Side view showing operation when attaching process cartridge to main body of image forming apparatus Side view when the process cartridge is attached to the main body of the image forming apparatus The figure which shows the state which removed the exposure apparatus from the main body of the image forming apparatus The figure which shows the state which removed the subprocess cartridge after removing only the exposure apparatus like FIG. FIG. 6 is a perspective view of the process cartridge cut along the line II in FIG. The perspective view which shows the positioning member vicinity of exposure apparatus Front view of process cartridge 1 is a side view of the vicinity of a print engine of an image forming apparatus according to a first embodiment of the present invention. The perspective view of the image forming apparatus of the 2nd Embodiment of this invention Side view of an image forming apparatus according to a second embodiment of the present invention. Side view of the vicinity of a print engine of an image forming apparatus according to a second embodiment of the present invention. Front view near the exposure head positioning device Perspective view of positioning member viewed from below Perspective view of positioning member viewed from above The perspective view which shows the state in which a part of positioning member was exposed from the flame | frame of a photoconductor. Side view showing a state in which the positioning member is in contact with the photosensitive member Schematic diagram showing a state in which the biasing force of the positioning member acts on the photosensitive member The perspective view which shows the edge part vicinity of a positioning device main body The perspective view which shows the inside of the end part vicinity of a positioning device main body Perspective view of eccentric gear Side view showing movement of eccentric gear Side view showing another example of positioning member The figure which shows the relationship between the positioning member of another example, a positioning device main body, and a photoreceptor. The schematic diagram which shows the state which the urging | biasing force of the positioning member of another example acts on a photoreceptor Furthermore, the perspective view which shows the state by which the positioning member of the other example is arrange | positioned on the photoreceptor. Further, a side view showing a state in which the positioning member of another example is arranged on the photosensitive member The figure which shows the state at the time of performing the focus position adjustment of the positioning device main body The figure which shows the state at the time of performing the focus position adjustment of the positioning device main body Diagram showing image resolution with respect to distance between exposure head and photoconductor Graph showing the relationship between the distance between the exposure head and the photosensitive member and the MTF

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Housing | casing 20 Paper cassette 21 Plate 30 Main body frame 40 Exterior door 50 Paper discharge part 200 Process cartridge 210 Subprocess cartridge 220 Frame 300 Exposure apparatus 300A Exposure head 360 Glass substrate 370 Positioning member 380 Exposure head positioning apparatus 400 Photosensitive Body 500 Development unit 600 Charger 700 Charger 800 Cleaner 900 Print engine 910 Print engine main unit

Claims (14)

A process cartridge detachably provided in an image forming apparatus, the process cartridge including at least a photosensitive member and an exposure device that exposes the photosensitive member,
The process cartridge is configured such that the photosensitive member and the exposure device are integrated via at least one member in a state in which a relative position is adjustable, and is detachable from the image forming apparatus. The process cartridge according to claim 1,
A process cartridge configured such that the exposure device is positioned above the photosensitive member when attached to the image forming apparatus. The process cartridge according to claim 1 or 2,
A process cartridge further comprising at least one of a charger, a static eliminator, and a cleaner. The process cartridge according to any one of claims 1 to 3,
During the exposure operation, the distance between the exposure device and the photoconductor is set to a first distance, and during the non-printing operation, the distance between the exposure device and the photoconductor is longer than the first distance. A process cartridge set at the second distance. The process cartridge according to any one of claims 1 to 4,
The exposure apparatus is a process cartridge that does not include an optical lens. The process cartridge according to any one of claims 1 to 5,
The exposure apparatus is a process cartridge having an electrical connection portion that receives power from the main body of the image forming apparatus. The process cartridge according to any one of claims 1 to 6,
A process cartridge further comprising a positioning member that is supported at both ends of the photoconductor, supports the exposure apparatus, and biases the exposure apparatus to a side away from the photoconductor. The process cartridge according to any one of claims 1 to 7,
The one member is composed of a frame that supports the rotating shaft of the photoconductor while the exposure apparatus is disposed.
An exposure apparatus that can be attached to the image forming apparatus by engaging the frame with a rotating member that is provided in the main body of the image forming apparatus and is rotatably attached to the main body.   An image forming apparatus comprising the process cartridge according to claim 1.   An exposure apparatus that is detachably provided in an image forming apparatus and exposes a photoreceptor of the image forming apparatus, and the exposure apparatus separates the exposure apparatus from the photoreceptor when attached to the image forming apparatus. An exposure apparatus configured to be held at a predetermined position relative to the photoconductor while resisting a biasing force of a biasing member biasing toward the side. An exposure apparatus according to claim 10, wherein
An exposure apparatus in which the urging member is provided in a main body of the image forming apparatus. An exposure apparatus according to claim 10 or 11,
The exposure apparatus is an exposure apparatus that does not include an optical lens. The exposure apparatus according to any one of claims 10 to 12,
The exposure apparatus is an exposure apparatus having an electrical connection portion on a surface that receives power from a main body of the image forming apparatus.   An image forming apparatus including the exposure apparatus according to claim 10.

Images