JP2005091482A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a simple protection mechanism of protecting a photoreceptor when an opening/closing member formed on one side wall of the image forming apparatus is opened, capable of reliably protecting the photoreceptor, and preventing paper transport from being interrupted by the protection mechanism in a state where the opening/closing member is kept closed. <P>SOLUTION: A strap 4a is stretched between a housing 1 and the opening/closing member 2, and a cover member 6 is attached to the strap 4a. When the member 2 is brought to an open position, the cover member 6 is moved to a position to cover the photoreceptor drum 3 and, on the other hand, when the member 2 is brought to a closing position, the cover member 6 is moved to a position to be stored. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a cover for preventing a photosensitive member from being exposed when a side cover formed on one side wall of a housing is opened. .

  In a series of image forming processes in which a sheet is fed from a sheet cassette, a toner image is transferred onto the sheet, the transferred toner image is fixed on the sheet, and discharged to a discharge unit, the path through which the sheet passes is vertically In recent years, so-called vertical conveyance type image forming apparatuses formed in the direction have been increasing. This is advantageous in that, since the transport path from paper feed to paper discharge is short, the time from when the copy start button is pressed until the copy is completed is shorter than before, and there is less paper jamming. Because.

  In such an image forming apparatus of vertical conveyance formation, a part of one side wall of the housing close to the conveyance path can be opened and closed in order to facilitate jam processing, maintenance and inspection. However, when a part of one side wall is opened, a part of the photoconductor is exposed to the outside, so that the operator's hand, jewelry, or tool may hit the photoconductor and damage the photoconductor. It was. In addition, the photoreceptor has been deteriorated by direct irradiation of the photoreceptor with external light.

Therefore, in order to prevent a hand or a tool from directly touching the photoconductor during jamming or the like, it has been conventionally proposed to provide a drum cover that covers the photoconductor. For example, in the proposed technique of Patent Document 1, when the side cover is opened, the rack gear attached to the side cover is detached from the gear of the drum cover, the drum cover is in a free state, and is rotated by the biasing force of the torsion spring. When the drum is covered and the side cover is closed, the rack gear of the side cover meshes with the gear of the drum cover and rotates against the urging force so that the drum cover returns to its original state.
JP-A-6-236080 (2nd to 3rd pages, FIGS. 1 to 3)

  However, in the proposed technique, since the drum cover is still positioned on the paper transport path with the side cover closed, there is a risk that paper transport may be hindered. In addition, the configuration becomes complicated and the number of parts increases, leading to an increase in cost.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a simple protection mechanism for protecting the photoconductor when the side cover is opened, and to reliably protect the photoconductor. Another object of the present invention is to provide an image forming apparatus capable of preventing the protection mechanism from hindering the conveyance of a sheet when the side cover is closed.

  According to the present invention, a housing, an opening / closing member provided on one side wall of the housing so as to be openable / closable, a photoconductor partially exposed to the outside when the opening / closing member is in the open position, A string-like body fixed to the opening / closing member, the other end fixed to the housing side, and constantly urged to the housing side by the urging means, and attached to the string-like body to cover the exposed photoreceptor portion A cover member, wherein the cover member moves to a position covering the photosensitive member when the opening / closing member is set to an open position, and moves to a position where the cover member is accommodated when the opening / closing member is set to a closed position. An image forming apparatus is provided.

  Here, from the viewpoint of reducing the number of members and reducing the manufacturing cost, the opening degree of the opening / closing member may be adjusted by the string-like body.

  Further, a plate-shaped member may be used as the cover member, and the cover member may be rotatably mounted between a pair of string-like bodies arranged in parallel with the upper end portion as a fulcrum. At this time, from the viewpoint of preventing the shake of the cover member and ensuring the protection of the photoreceptor, a magnet or a magnetic body is attached to the lower end portion of the cover member and the cover member is moved to a position covering the photoreceptor. Preferably, a magnetic body or a magnet is attached to a portion of the housing facing the magnet or the magnetic body, and the lower end portion of the cover member is firmly fixed to the housing.

  Moreover, a sheet-like thing may be used as a cover member, and this may be stretched around a pair of string-like bodies arrange | positioned in parallel.

  In the image forming apparatus of the present invention, an opening / closing member is provided on one side wall of the housing so as to be freely opened / closed. Therefore, when the paper is jammed, the opening / closing member can be opened to open most of the sheet conveyance path. The jammed paper can be easily removed. In addition, a string-like body is stretched between the opening / closing member and the housing, and a cover member is attached to the string-like body, and when the opening / closing member is set to the open position, the cover member moves to a position covering the photoconductor. When the cover is moved to the closed position, the cover member is moved to the stored position.Therefore, when working with the open / close member opened, the photoconductor is not damaged by the operator's hand or tool, and the light Deterioration can also be prevented. Furthermore, there is no possibility that the cover member may interfere with the conveyance of the paper when the opening / closing member is closed. Further, since the number of parts newly required for protecting the photoconductor is smaller than that of the conventional one, an increase in manufacturing cost can be suppressed.

  If the opening degree of the opening / closing member is adjusted by the string-like body, the number of members can be reduced and the manufacturing cost can be reduced.

  The image forming apparatus of the present invention will be described below with reference to the drawings. The present invention is not limited to these embodiments. FIG. 1 is a schematic sectional view showing an embodiment of the image forming apparatus of the present invention. The image forming apparatus shown in the figure includes a substantially rectangular parallelepiped housing, and a photosensitive drum (photosensitive member) 3 is disposed at a substantially central portion in the housing. The surface of the photosensitive drum 3 is uniformly charged positively or negatively by a charging device 81. Image data input from an input unit (not shown) is written on the surface of the photosensitive drum 3 by a laser scanner (exposure device) 82, and an electrostatic latent image is formed on the surface of the photosensitive drum 3. Specifically, in the case of the reverse development method, the charge corresponding to the image is removed, and in the case of the regular development method, the charge corresponding to the background is removed to form an electrostatic latent image. Next, the developing device 83 visualizes the electrostatic latent image on the photosensitive drum 3 with toner. At this time, the charging polarity of the toner is the same as the charging polarity of the photosensitive drum 3 in the case of the reversal development method, and is opposite to the charging polarity of the photosensitive drum 3 in the case of regular development. The developing device is provided with a replaceable toner cartridge 86, and toner is sequentially supplied from the toner cartridge 86 to the developing device 83 via a toner supply path (not shown).

  On the other hand, the paper P stored in the paper feed cassettes 90a and 90b disposed in the lower part of the housing 1 is pulled out by the pickup roller 91, and is sandwiched by the paper feed roller 92 and the separating roller 93 to the transport path. Sent. The paper P supplied from the paper feed cassette 90a is registered on the photosensitive drum 3 by the registration roller pair 95, and the paper P supplied from the paper supply cassette 90b is supplied by the registration roller pair 95 via the conveyance roller pair 94. The toner image is sent to the transfer unit at the same timing as it reaches the transfer unit. In the transfer portion, the sheet P is sandwiched between the photosensitive drum 3 and the transfer roller 84, and a charge having a polarity opposite to the charging polarity of the toner is applied to the transfer roller 84. Toner image moves onto the paper P. On the other hand, the toner remaining on the photosensitive drum 3 without moving onto the paper P is removed and collected by the cleaning roller 85. The paper P on which the toner image is placed is conveyed to the fixing roller pair 96. Here, the toner image is heated and pressurized by the fixing roller pair 96 and fixed on the paper P. The paper P is discharged to the paper discharge unit 98 by the discharge roller pair 97.

  1 and FIG. 2, in the illustrated image forming apparatus, an opening / closing member 2 is illustrated in FIG. 1 on one side wall (the left side wall in FIGS. 1 and 2) of the housing 1. It is rotatably mounted between a closed position and an open position shown in FIG. More specifically, a support shaft 11 extending in a direction perpendicular to the paper surface in FIGS. 1 and 2 is disposed at the lower end portion of the housing 1, and the lower end portion of the opening / closing member 2 rotates about the support shaft 11. It is installed freely. The opening / closing member 2 is provided with an outer roller in the conveying roller pair 94, an outer roller in the registration roller pair 95, and a transfer roller 84.

  On the other hand, above the photosensitive drum 3 in the housing 1, a pair of take-up rollers (biasing means) 5a and 5b around which straps (strings) 4a and 4b are wound are provided in the front-rear direction (perpendicular to the paper surface). It is arranged. The strap 4b and the winding roller 5b are not shown in FIGS. 1 and 2 because they overlap the strap 4a and the winding roller 5a. Therefore, in the description of FIGS. 1 and 2, the strap 4b and the take-up roller 5b are omitted, and only the strap 4a and the take-up roller 5a are described. A coil spring (not shown) is incorporated in the take-up roller 5a, and the strap 4a is always urged in a direction to be taken up by the take-up roller 5a. The tip of the strap 4 a is fixed to the fixing portion 21 of the opening / closing member 2. Therefore, the strap 4a is stretched between the fixing portion 21 of the opening / closing member 2 and the take-up roller 5a while changing the direction by the first roller 7a. Furthermore, an upper end portion (right side in FIG. 1) of a plate-like cover member 6 having a square shape in plan view is attached between the straps 4a and 4b so as to be swingable with respect to the straps 4a and 4b. As shown in FIG. 1, when the opening / closing member 2 is in the closed position, the cover member 6 is in a retracted state retracted from the paper transport path.

  Next, when the opening / closing member 2 rotates to the open position shown in FIG. 2, the strap 4a is pulled out from the take-up roller 5a. As a result, the cover member 6 moves to the left in FIG. 2, and when the attachment portion 61 with the strap 4a exceeds the first roller 7a, the cover member 6 rotates by its own weight so that the free end side is downward. As a result, the exposed photosensitive drum 3 is covered with the cover member 6. Further, the strap 4a is set so that the pull-out from the take-up roller 5a stops at the open position shown in FIG. 2, and the opening / closing member 6 rotates beyond the open position shown by the strap 4a. Is blocked.

  3 and 4 show state diagrams when the opening / closing member 2 is in the closed position and in the open position. The pair of left and right straps 4a and 4b are stretched in parallel between the winding rollers 5a and 5b and the opening / closing member 2 (shown in FIGS. 1 and 2). Since the distance between the straps 4a and 4b is wider than the width in the axial direction of the photosensitive drum 3, the transfer roller 84 can contact and separate from the photosensitive drum 3 without being obstructed by the straps 4a and 4b. As shown in FIG. 3, when the opening / closing member 2 is in the closed position, the cover member 6 is housed above the photosensitive drum 3. At this time, the free end side of the cover member 6 is supported by the upper surface of the first roller 7a. A transfer roller 84 is in contact with the transfer area of the photosensitive drum 3 (the left portion of the photosensitive drum in the figure). Then, the paper P is sandwiched and conveyed between the photosensitive drum 3 and the transfer roller 84, and at this time, the toner image on the photosensitive drum 3 is transferred onto the paper P.

  As shown in FIG. 4, when the opening / closing member 2 is in the open position, the transfer roller 84 attached to the opening / closing member 2 is separated from the photosensitive drum 3. As a result of the straps 4a and 4b being pulled out to the left in the figure by the rotation of the opening / closing member 2, the cover member 6 is also moved to the left, and the attachment portion 61 with the straps 4a and 4b exceeds the first roller 7a. By the way, the free end of the cover member 6 rotates the free end side counterclockwise around the mounting portion 61 to cover the exposed portion which is the transfer area of the photosensitive drum 3. At this time, the free end side of the cover member 6 is magnetically attracted and fixed to the housing by the magnetic body 62 attached to the free end side of the cover member 6 and the magnet 13 attached to the housing portion 12 facing the magnetic body 62. . As a result, even if the operator's hand or the like comes into contact, the cover member 6 does not swing, so that the workability is improved and the protection property of the photosensitive drum 3 is also improved.

  When the opening / closing member 2 is closed again, the straps 4a and 4b are wound by the winding rollers 5a and 5b while maintaining the tension, and the cover member 6 is also moved accordingly. Specifically, when the attachment portion 61 of the cover member 6 exceeds the first roller 7a, the cover member 6 starts to rotate clockwise around the attachment portion 61, and when the cover member 6 becomes horizontal, the cover member 6 rotates. The movement stops and moves in the direction of the take-up rollers 5a and 5b in a horizontal state. When the rear end of the cover member 6 is placed on the first roller 7a, the opening / closing member 2 reaches the closed position, and the state shown in FIG. 3 is obtained.

  Next, a second embodiment of the present invention will be described. FIGS. 5 and 6 show state diagrams of the cover member 6 ′ in the present embodiment when the opening / closing member 2 is in the closed position and in the open position. A pair of left and right parallel straps 4a and 4b are arranged between a winding roller 5a and 5b and an opening / closing member 2 (shown in FIGS. 1 and 2) by a first roller 7a and a second roller 7b. It is stretched in a crank shape so as to hang down in the vicinity of the exposed portion of the photosensitive drum. Similar to the above-described embodiment, the distance between the straps 4a and 4b is wider than the axial width of the photosensitive drum 3, so that the transfer roller 84 can contact and separate from the photosensitive drum 3 without being obstructed by the straps 4a and 4b. It has become. The cover member 6 'used here is a sheet-like flexible member, and the left and right sides thereof are attached to the straps 4a and 4b, respectively. In this figure, the entire left and right sides of the cover member 6 'are attached to the straps 4a and 4b. However, the attachment of the cover member 6' is not limited to this, and at least the front and rear portions in the cover member moving direction. Can be attached to the strap.

  As shown in FIG. 5, when the opening / closing member 2 is in the closed position, the cover member 6 ′ is housed above the photosensitive drum 3. Of course, the storage position of the cover member 6 ′ is not limited to this, and may be appropriately determined in consideration of the arrangement of members in the apparatus. Next, when the opening / closing member 2 is opened, the straps 4a, 4b are pulled out by the rotation of the opening / closing member 2, and the cover member 6 'also moves accordingly. When the opening / closing member 2 reaches a predetermined opening, the straps 4a, 4b are not drawn from the winding rollers 5a, 5b, and the rotation of the opening / closing member 2 is stopped. That is, the opening degree of the opening / closing member 2 is adjusted by the pull-out length of the straps 4a and 4b. As shown in FIG. 6, when the opening / closing member 2 stops rotating, the cover member 6 ′ is attached to the straps 4a and 4b so that the cover member 6 ′ covers the exposed portion of the photosensitive drum 3. . Since the cover member 6 'is flexible as described above, it may come into contact with the photosensitive drum 3 when pressed by the operator's hand or tool. Even those that do not adversely affect are preferable. Further, in order to suppress the light deterioration of the photosensitive drum 3, a light-shielding one is preferable. When the opening / closing member 2 is closed again, a movement opposite to the movement from the open position to the closed position occurs, and the cover member 6 ′ is in the housed state shown in FIG. 5.

  In the embodiment described above, the opening degree of the opening / closing member is adjusted by the strap, but it goes without saying that an opening degree adjusting member may be provided separately. However, from the viewpoint of reducing the number of parts and reducing the manufacturing cost, it is preferable that the strap has an opening adjustment function.

1 is a schematic cross-sectional view illustrating an example of an image forming apparatus of the present invention. It is a schematic sectional drawing when an opening-and-closing member is made into an open position. It is a state figure of a plate-shaped cover member when an opening-and-closing member is a closed position. It is a state figure of a plate-shaped cover member when an opening-and-closing member is an open position. It is a state figure of a sheet-like cover member when an opening-and-closing member is a closed position. It is a state figure of a sheet-like cover member when an opening-and-closing member is an open position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Opening / closing member 3 Photosensitive drum (photosensitive member)
4a, 4b Strap (string)
5a, 5b Winding roller (biasing means)
6, 6 'cover member 7a 1st roller 7b 2nd roller 10
DESCRIPTION OF SYMBOLS 11 Support shaft 13 Magnet 21 Fixed part 61 Fixed part 62 Magnetic body

Claims (5)

A housing, an opening / closing member provided on one side wall of the housing so as to be freely opened and closed, a photoconductor partially exposed to the outside when the opening / closing member is in an open position, and one end fixed to the opening / closing member, A string-like body whose other end is fixed to the housing side and is always urged to the housing side by the urging means, and a cover member that is attached to the string-like body and covers the exposed photoconductor portion,
An image forming apparatus, wherein the cover member moves to a position covering the photoconductor when the opening / closing member is in the open position, and moves to a position in which the cover member is housed when the opening / closing member is in the closed position.   The image forming apparatus according to claim 1, wherein the opening degree of the opening / closing member is adjusted by the string-like body.   3. The image forming apparatus according to claim 1, wherein the cover member is plate-shaped, and is rotatably attached between a pair of string-like bodies arranged in parallel with an upper end portion as a fulcrum.   A magnet or a magnetic body is attached to a lower end portion of the cover member, and the magnetic body or the magnet is attached to a portion of the housing facing the magnet or the magnetic body when the cover member moves to a position covering the photoconductor. Item 4. The image forming apparatus according to Item 3.   The image forming apparatus according to claim 1, wherein the cover member has a sheet shape and is stretched between a pair of string-like bodies arranged in parallel.

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