JP2008292790A - Process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge attached to or detached from an image forming apparatus, the process cartridge being designed so as to reduce cost with a simple structure used for a light shield plate for opening or closing an exposure opening and a blocking member for blocking entry of foreign matter such as dust, thereby reducing the number of components. <P>SOLUTION: The exposure opening 27 is provided in a cartridge frame body 30a. A flexible light-shield blocking sheet 100 is attached so as to close the exposure opening 27. When the cartridge frame body 30a is attached to or detached from the main body of an image forming apparatus, the light-shield blocking sheet 100 blocks a space between the exposure opening 27 and a cleaning unit 14 (process means) 14 by means of a cut-out portion 100c bent when attached, and opens the exposure opening 27. When the cartridge frame body 30a is detached from the main body of the image forming apparatus, the light-shield blocking sheet 100 closes the exposure opening 27 and prevents surrounding natural light or illuminating light from entering the cartridge frame body 30a therefrom. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus (hereinafter, simply referred to as “image forming apparatus”) using an electrophotographic system, and to a process cartridge that can be attached to and detached from the image forming apparatus.

  An electrophotographic image forming apparatus forms an image on a sheet such as a transfer material, which is a recording medium, using an electrophotographic image forming process. These include electrophotographic copying machines, electrophotographic printers such as laser printers and LED printers, factory devices, word processors, and multifunctional multifunction devices. The process cartridge includes, for example, an electrophotographic photosensitive member (hereinafter simply referred to as “photosensitive drum”) which is a drum-shaped image carrier, and at least developing means is integrated as process means acting on the photosensitive drum. This is a cartridge.

  In an image forming apparatus, a process cartridge system in which such a process cartridge can be easily attached and detached by a user has become mainstream. According to this process cartridge system, the user can perform maintenance of the apparatus by himself / herself without relying on a service person, so that the operability can be remarkably improved. For this reason, use in image forming apparatuses has been increasing, and a representative example has been proposed by the present applicant (see, for example, Patent Document 1).

  In the case of such a process cartridge, an exposure opening for guiding exposure light obtained by reading image information of an original and irradiating the photosensitive drum is provided at a position near the photosensitive drum of the cartridge frame. If the process cartridge is removed from the image forming apparatus and left on the desk or the like, ambient ambient light or illumination light enters the cartridge frame from the exposure opening, generating optical memory on the photosensitive drum, and removing dust, etc. Foreign matter may enter. In order to prevent this, a structure in which the exposure opening is opened and closed with an opening / closing door as necessary has already been put into practical use.

  An example of the process cartridge will be schematically described with reference to FIGS.

  In the case of the process cartridge 30 shown in FIGS. 9 and 10, the exposure opening 27 provided at the upper part of the cartridge frame 30a is opened and closed by a light shielding plate. On the side of the light shielding plate 28 facing the cleaning unit 14, a convex portion 28a is provided as a restraining portion bent into an L shape. FIGS. 11 and 12 show the light shielding plate 28 when the process cartridge 30 loaded in the image forming apparatus can be used. When the process cartridge 30 is taken out from the image forming apparatus in this state, the light shielding plate 28 is rotated in the direction indicated by the arrow a in FIG. That is, as shown in FIGS. 9 and 10, the exposure opening 27 is blocked to block natural light and illumination light from entering the cartridge frame 30, and foreign matters such as dust prevent entry. Further, the convex portion 28a provided in the exposure opening 27 is bent and raised in an L shape so as to face the cleaning unit 14, and when the cartridge 30 is to be loaded into the image forming apparatus in this state, the convex portion 28a becomes the imaging element. It abuts on the array (see FIG. 1: reference numeral 2). That is, the process cartridge 30 cannot be loaded, and the user is made aware that the exposure opening 27 is blocked by the light shielding plate 28. Conversely, if the process cartridge 30 is to be loaded into the image forming apparatus in the state of FIGS. 11 and 12, the projection 28a does not contact the imaging element array, so that loading is possible.

  On the other hand, as shown in FIGS. 10 and 12, a shielding member 101 is provided that partitions and shields the cleaning unit 14 from the exposure opening 27. The shielding member 101 is formed by bending sheet-like PET or PE into an L shape, and is fixed to the inner surface of the cartridge frame 30a by an adhesive means such as a double-sided tape.

  The shielding member 101 functions as follows. The toner adhering to the drum surface of the photosensitive drum 3 is scraped off by the rubber blade 66 of the cleaning unit 14. When viewed microscopically, a very small amount of toner that does not affect the image passes through the rubber blade 66 and remains on the drum surface of the photosensitive drum 3. It has been empirically found by the inventors' research and experiment that such a small amount of toner is floating during the operation of the image forming apparatus. There is no particular problem when the imaging element array is arranged at a sufficient distance from the exposure opening 27. In order to reduce the size of the image forming apparatus as much as possible, the image forming device array and the like are arranged close to each other in the illustrated copying machine. In such a type of image forming apparatus, when the machine is used for a long time, the floating toner may pass through the exposure opening 27 and adhere to the imaging element array, and may be shielded from light and cause an image defect. In order to solve this problem, the cleaning unit 14 and the opening 27 are partitioned by the shielding member 101 and blocked.

Japanese Examined Patent Publication No. 3-56472

  In the case of the process cartridge 30 shown in FIGS. 9 to 12, the light shielding plate 28 is opened in the state shown in FIGS. 11 and 12 and the exposure opening 27 is opened in preparation for insertion into the image forming apparatus and loading. It is necessary to keep. Further, after the cartridge is loaded, the light shielding plate 28 must be closed again, and the user is forced to carry out various troublesome operations. Further, after removing the process cartridge 30 from the image forming apparatus, it is necessary to close the light shielding plate 28 to the state shown in FIGS. If the user forgets or neglects the returning operation, an optical memory is generated on the photosensitive drum 3 as described above, and there is a problem that foreign matters such as dust enter. In order to prevent this, since the shielding member 101 that opens and closes in conjunction with the operation when the process cartridge 30 is attached and detached is provided, the number of parts and the number of assembling steps are increased, and the cost is considerably increased.

  The object of the present invention is to realize a simple structure that can be used as both a light shielding plate that opens and closes an exposure opening and a shielding member that shields entry of foreign matter such as dust, and a process that can greatly reduce the cost by halving the number of parts An object is to provide a cartridge and an image forming apparatus equipped with the cartridge.

In order to achieve the above object, a typical process cartridge of the present invention is a process cartridge that is detachably attached to an image forming apparatus main body having an exposure unit that emits exposure light.
An electrophotographic photoreceptor;
A cartridge frame that supports the electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member;
An exposure opening provided in the cartridge frame for guiding the exposure light to the electrophotographic photosensitive member;
When the cartridge is mounted on the image forming apparatus main body, the sheet shape moves by contacting the image forming apparatus main body, one end is fixed to the outer surface of the cartridge frame and the other end is a free end. A light shielding member that closes the exposure opening when the cartridge is removed from the image forming apparatus main body, and that opens the exposure opening when the cartridge is attached to the image forming apparatus main body. A light shielding member having a shielding part which enters between the electrophotographic photosensitive member and the process means when the cartridge is mounted on the image forming apparatus main body,
It is characterized by having.

  According to the process cartridge of the present invention, the function of opening and closing the exposure opening by the sheet-shaped light shielding / shielding member provided on the cartridge frame, and the shielding for blocking foreign matter from entering between the exposure opening and the process means. Combined with function. Therefore, the number of parts is reduced by half, and the cost can be greatly reduced with an extremely simple configuration.

  Hereinafter, preferred embodiments of a process cartridge and an image forming apparatus according to the present invention will be described in detail with reference to the drawings. In addition, the same reference numerals are given to the same or the same kind of members and devices of the process cartridge illustrated in FIGS. 9 to 12, and the description of the overlapping parts is omitted, and the main part of this embodiment is omitted. Will be described by clarifying the difference from the structure of FIGS.

    FIG. 1 shows a copying machine using an electrophotographic image forming process as a specific example of the image forming apparatus of this embodiment. FIG. 2 shows a state where the image forming apparatus main body (hereinafter referred to as “apparatus main body”) is opened so that the process cartridge can be attached and detached. The apparatus main body is composed of two large parts, an upper frame 17 and a lower frame 18. The open state in FIG. 2 refers to a state in which the upper and lower frame bodies 17 and 18 that are rotatably connected by the hinge shaft 19 are opened in a direction away from each other. An imaging element array (exposure means) 2 and a process cartridge 30 are mounted on the upper frame 17. The lower frame 18 is equipped with a feeding roller 6, a transfer charger 8, a separating unit 13, a guide 9, a fixing device 10, and the like arranged along the sheet conveyance path.

  In the upper frame 17, the document table 1 made of a transparent material can be reciprocated in the horizontal direction indicated by arrows in FIG. The imaging element array 2 reads the image information of the document placed on the document placement table 1, and the photosensitive drum (electrophotographic photoreceptor) 3 mounted with the exposure light of the image in the process cartridge 30. Exposure light is irradiated on the top by a slit exposure method. Further, it has an illumination system 15 for exposing a document, and has a filter 16 such as a heat ray absorption filter.

  Here, the structure of the process cartridge 30 according to the present embodiment will be described with reference to FIGS. The photosensitive drum 3 is supported inside the cartridge frame 30a constituting the cartridge frame, and the developing unit 5, which is a process means, the cleaning unit 14, and the charging roller 4 are provided along the periphery of the photosensitive drum 3. Etc. are integrally arranged. The cartridge frame 30a is formed of a light shielding material. The photosensitive drum 3 rotates in a clockwise direction indicated by an arrow in FIG. The charging roller 4 applies a charging bias voltage to the drum surface of the photosensitive drum 3 to uniformly charge it. Further, the developing unit 5 exposes the uniformly charged surface of the photosensitive drum 3 by irradiating exposure light of a read image from the imaging element array 2, and forms the formed electrostatic latent image. It develops and visualizes using a developing agent (toner). In such an image forming process, the untransferred residual toner remaining on the photosensitive drum 3 is collected by the cleaning unit 14.

    On the other hand, in FIG. 1 and FIG. 2, a sheet P such as a transfer material serving as a recording medium is conveyed toward the photosensitive drum 3 on the process cartridge side by a feeding roller 6 and a registration roller 7 and is transferred by a transfer charger 8. The toner image on the photosensitive drum 3 is transferred. Thereafter, the sheet P is separated from the photosensitive drum 3 by the separating unit 13, passes through the guide 9, and is sent to the fixing device 10 by the conveyance roller 9 a positioned at the end of the conveyance path. In the fixing device 10, the toner image on the sheet P is heated and pressed to be permanently fixed, and the fixed sheet P is discharged to the paper discharge tray 12 by the discharge roller 11.

  When the photoconductor drum 3 is replaced with a new one, the maintenance work can be simplified and reduced by replacing the devices and units inside the process cartridge 30 at the same time. In this case, the process cartridge 30 is attached to and detached from the apparatus main body with respect to the upper frame 17. As shown in FIGS. 1 and 2, the upper frame 17 is provided with a pair of parallel rails 31 and 32, and a cartridge frame 30 a is engaged and placed on the rails. Attachment / detachment is performed by moving the drum in the direction of the drum rotation axis. When the cartridge is attached or detached, the upper and lower frame bodies 17 and 18 are separated in the state shown in FIG. 2, and the cartridge frame body 30a is moved on the rails 31 and 32 in the direction of pushing or pulling out.

  As can be seen from the above, in the present embodiment, the upper frame 17 can be separated and coupled by rotating from the hinge shaft 19 with respect to the lower frame 18. Will also serve as the main body opening / closing cover.

  On the other hand, as shown in FIG. 3, the cartridge frame 30 a facing the imaging element array 2 has an exposure for guiding exposure light of image information read from the original to the drum surface of the photosensitive drum 3. An opening 27 is provided therethrough. The exposure opening 27 is provided at a position close to the drum peripheral surface of the photosensitive drum 3. Therefore, if the process cartridge 30 is removed from the upper frame 17 and left on the desk or the like, an optical memory is generated on the photosensitive drum 3 due to ambient natural light or illumination light, and foreign matter such as dust enters. Sometimes.

  4 is provided with a light-shielding shielding sheet (light-shielding shielding member) 100 having a flexible sheet shape shown in FIG. 4 that opens and closes the exposure opening 27 and partitions and blocks the exposure opening 27 and the cleaning unit 14. It is a summary of an embodiment. The light shielding / shielding sheet 100 is a member that has both functions of the conventional light shielding plate 28 and the shielding member 101 shown in FIGS. 9 to 12.

  In FIG. 4, when the process cartridge is not attached with the flat light-shielding shielding sheet 100 at a low cost, the exposure opening 27 provided in the cartridge frame 30a is formed as a light shielding portion. It is closed with 100e. Further, in the mounted state, the exposure opening 27 is opened, and the exposure opening 27 and the cleaning unit 14 are partitioned and blocked by a shielding portion 100c. The light shielding / shielding sheet 100 is made of a resin such as PET or PE having light shielding properties, and a film having excellent flexibility is used. A part of the light shielding / shielding sheet 100 is provided with a U-shaped cut part 100c surrounded by a cutting line from three sides, and the cut part 100c divides the region into an internal shield part 100b and an external part 100a. Further, an adhesive portion 100d using a double-sided tape or the like is provided at one end in the longitudinal direction of the light shielding / shielding sheet 100. As shown in the drawing, a double-sided tape is also attached to the back side of the light shielding / shielding sheet 100 to form an adhesive portion 100d. A light shielding part 100e for shielding exposure light is provided between the adhesive part 100d and the shielding part 100b.

  As shown in FIG. 3 and FIG. 5 which is an enlarged view of a main part viewed from above, the light shielding / shielding sheet 100 is adhered to the outer surface of the part facing the exposure opening 27 of the cartridge frame 30a. That is, the adhesive portion 100d formed of the double-sided tape of the light shielding shielding sheet 100 is attached and fixed to the upper surface of the cartridge frame 30a facing the developing unit 5, and the other end side of the light shielding shielding sheet 100 is a free end. is there. In addition, a slit 45 is formed in a part of the cartridge frame 30a at the upper part of the cartridge frame 30a facing the cleaning unit 14 and having a length substantially the same as the drum length of the photosensitive drum 30. As shown in FIG. 6 and FIG. 7 which is an enlarged view seen from above, the tip of the shielding part 100 b of the light shielding sheet 100 is inserted into the slit 45. In the mounted state in which the process cartridge 30 is inserted into the upper frame 17 and loaded, the imaging element array 2 enters the recess provided in the cartridge frame 30a and faces the exposure opening 27 opened at the bottom thereof. . In accordance with the insertion operation, the light-shielding shielding sheet 100 is pressed from above by the imaging element array 2 as shown in FIG. 6, and is pressed into the concave portion on the cartridge frame side using flexibility.

  Referring to FIG. 7, the central portion of the light shielding / shielding sheet 100 is bent and approaches the exposure opening 27, and the free end of the light shielding / shielding sheet 100 is pulled in the direction of the arrow and slides and moves toward the exposure opening 27. With this movement, the shielding portion 100b of the light shielding / shielding sheet 100 enters and bends into the slit 45 of the cartridge frame 30a and further penetrates into the back to partition the exposure opening 27 and the cleaning unit 14 and block them. As the shielding portion 100b of the light shielding shielding sheet 100 enters the slit 45, the cutting line of the notched portion 100c of the light shielding shielding sheet 100 is expanded, and slides on the exposure opening 27 from the imaging element array 2. Becomes an opening through which the exposure light passes. A light shielding / shielding sheet 100 obtained by this deformation is shown in FIG. That is, the light shielding / shielding sheet 100 is bent downward by the imaging element array 2, the free other end side shown in FIG. 7 slides in the direction of the arrow, and the shielding part 100b of the cut portion 100c enters the slit 45 and moves downward. Invade towards you. At the same time, since the shielding part 100b has entered the lower part, the U-shaped cut part 100c is greatly bent and slides to the upper part of the exposure opening 27 while the cutting line is expanded.

  Note that the toner is floating during operation during image formation. In the state where the process cartridge 30 is taken out from the upper frame 17 which is the apparatus main body, it is not necessary to partition the exposure opening 27 and the cleaning unit 14 from each other. Further, in the state shown in FIG. 4, the U-shaped outside 100 a in the notch 100 c of the light shielding / shielding sheet 100 completely covers the concave portion of the cartridge frame 30 a having the exposure opening 27. The width dimension of the notch 100c, that is, the direction of the drum rotation axis of the photosensitive drum 30 is slightly shorter than the length dimension of the imaging element array 2 and slightly longer than the width of the imaging element array 2 through which light passes. ing. Therefore, when the process cartridge 30 is taken out from the upper frame 17 which is the apparatus main body, it is restored to a flat shape by the elastic restoring force of the light shielding / shielding sheet 100, and the exposure opening 27 can be shielded from light.

  In the case of the present embodiment, in FIG. 6, the process cartridge 30 is inserted into the upper frame 17 and loaded with the lower frame 18 closed in a state where the imaging element array 2 is in contact with the light shielding sheet 100. The state, that is, the state shown in FIG. 1 has been described. It is only for convenience of explanation. In a state where the upper frame 17 and the lower frame 18 are separated and opened, that is, when the process cartridge 30 is mounted on the upper frame 17 side in the state shown in FIG. It is in contact. In other words, the imaging element array 2 is in contact with the light shielding / shielding sheet 100 in the open state of the apparatus main body with the upper frame 17 opened without the process cartridge 30 being completely removed from the apparatus main body.

  Further, as materials and materials used as the cartridge frame 30a of the process cartridge 30 and the light shielding / shielding sheet 100, opaque materials such as noryl resin, polycarbonate resin, ABS resin, metal, and rubber that block light almost completely are used. be able to. Further, the light shielding / shielding sheet 100 is not only shielded against the photosensitive drum 3 but also as a protective cover that prevents the user's hand from touching the photosensitive drum 3 and prevents foreign matter from entering through the exposure opening 27. Is also useful.

  As described above, according to the first embodiment, it is possible to realize a significant cost reduction with an extremely simple configuration in which only the flexible film-shaped light shielding / shielding sheet 100 is provided. That is, the function of opening / closing the exposure opening 27 and the function of blocking the partition between the exposure opening 27 and the cleaning unit 14 are combined with one light shielding / shielding sheet 100 in conjunction with the attaching / detaching operation of the process cartridge 30. Therefore, the number of parts can be almost halved compared to the conventional case.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described.

  In the first embodiment, even if the process cartridge 30 is not completely removed from the apparatus main body, the upper and lower frame bodies 17 and 18 that open and close in accordance with the attaching / detaching operation of the process cartridge 30 are opened, and the imaging element array 2 is The form which contact | abutted to the light-shielding shielding sheet 100 was shown. After loading the process cartridge 30 on the upper frame body 17 side, the upper frame body 17 and the lower frame body 18 are closed, and the process cartridge 30 is linked to an operation for bringing the apparatus main body into an operable state. Accordingly, the imaging element array 2 may be configured to enter a recess provided in a part of the upper portion of the cartridge frame 30a and to be pressed into contact with the light shielding sheet 100 in the recess.

  In the above, several embodiments of the image forming apparatus of the present invention have been described. However, the present invention is not limited thereto, and other embodiments, application examples, modified examples, and modifications are within the scope not departing from the gist of the present invention. Combinations thereof are also possible.

  For example, in each of the above embodiments, a copying machine is shown as an example of an image forming apparatus in which the imaging element array 2 is placed close to the photosensitive drum 3. The present invention can be applied not only to such a copying machine but also to an LED printer, a laser beam printer, or the like. In the case of an LED printer, an LED is close to the photosensitive drum 3, and in the case of a laser beam printer, a mirror that reflects laser light, a lens that refracts the lens, and the like. Further, the structure in which the light shielding / shielding sheet 100 partitions and blocks between the cleaning unit 14 and the exposure opening 27 has been described as a gist. Since the floating toner may be generated from the developing unit, the present invention can be applied to a structure in which the space between the developing unit 5 and the exposure opening 27 is shielded.

1 is a diagram illustrating a copier that is a specific example of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a state in which the upper frame and the lower frame are separated and opened in the copier. Sectional drawing which shows the state which took out the process cartridge of 1st Embodiment from the upper frame which is an apparatus main body. The figure which shows the light-shielding shielding sheet as a summary member of 1st Embodiment. The figure which shows the light-shielding shielding sheet of the state of FIG. 4 as seen from above. The figure which shows the state which combines the interruption | blocking function between the opening / closing function of exposure opening, and the cleaning unit in a light-shielding shielding sheet. The figure which shows the light-shielding shielding sheet of the state of FIG. The figure which shows only a light-shielding shielding sheet alone. The perspective view which shows the external appearance of the conventional process cartridge. Sectional drawing which shows the state which closed the exposure opening in the process cartridge of the prior art example. The perspective view which shows the external appearance of the process cartridge of the prior art example. Section showing the exposure opening in the process cartridge of the conventional example

Explanation of symbols

1 Document Placement Table 2 Imaging Element Array (Exposure Means)
3 Photosensitive drum (electrophotographic photosensitive member)
4 Charging roller 5 Developer unit 14 Cleaning unit (process means)
27 exposure opening 28 light shielding plate 30 process cartridge 30a cartridge frame 84 developing sleeve 100 light shielding sheet (light shielding member)
100a Outside outside cutting line 100b Shielding portion 100c Cutting portion 100e Shielding portion t Toner (Developer)

Claims (4)

A process cartridge that is attachable to and detachable from an image forming apparatus main body having exposure means for emitting exposure light,
An electrophotographic photoreceptor;
A cartridge frame that supports the electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member;
An exposure opening provided in the cartridge frame for guiding the exposure light to the electrophotographic photosensitive member;
When the cartridge is mounted on the image forming apparatus main body, the sheet shape moves by contacting the image forming apparatus main body, one end is fixed to the outer surface of the cartridge frame and the other end is a free end. A light shielding member that closes the exposure opening when the cartridge is removed from the image forming apparatus main body, and that opens the exposure opening when the cartridge is attached to the image forming apparatus main body. A light shielding member having a shielding part which enters between the electrophotographic photosensitive member and the process means when the cartridge is mounted on the image forming apparatus main body,
A process cartridge comprising:   The shielding portion is formed by providing a cut portion in the light shielding shielding member, and is bent by being pressed by the cartridge frame when the process cartridge is attached to the image forming apparatus main body. The process cartridge according to claim 1.   3. The process cartridge according to claim 2, wherein when the cartridge is mounted on the image forming apparatus main body, the exposure light passes through an opening formed by bending the shielding portion.   4. The process cartridge according to claim 1, wherein the light shielding member is moved by contacting the exposure unit.

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