JP2006047791A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means capable of easily making a transfer roller near to or away from a photoreceptor drum for space saving and facilitation so that a process unit including the photoreceptor drum may be inserted in/pulled out from the front side of an image forming apparatus without damaging the photoreceptor drum or the like, and also facilitating access to a conveying path near the photoreceptor drum from the side of the apparatus for elimination of paper jam, or the like. <P>SOLUTION: In the copying/facsimile compound machine 100, the process unit 50 is provided to be inserted in/pulled out from the front side of the machine 100 in the shaft direction of the photoreceptor drum 51, and a transfer guide 73 is provided to be tilted in a direction where the transfer roller 55 and the photoreceptor drum 51 are made to contact with/separate from each other and open/close together with a jam access cover 31, then a latch 81 is provided to move to an abutting position where it abuts on the jam access cover 31 and a release position where the abutting is released, and an operation lever 83 for moving the latch 81 to the abutting position and the release position is provided to be operated from the front side of the machine 100 with respect to the jam access cover 31. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a printer, a facsimile, or a copying machine that forms an image such as characters and graphics on a recording sheet.

  Conventionally, there are printers, facsimiles, copiers, and the like as image forming apparatuses for recording characters, graphics, and the like on recording paper. FIG. 10 shows an example of an image forming unit of a conventional image forming apparatus. The surface of the photosensitive drum 902 is charged by a charging device 901 to which a predetermined bias voltage is applied, and the LED head 903 is image information. In response to this, the photosensitive drum 902 is selectively exposed to form an electrostatic latent image on the surface of the photosensitive drum 902. A developing device 904 supplies charged toner to the electrostatic latent image to form a toner image, and the toner image is transferred onto a recording sheet by a transfer roller 905 to which a predetermined bias voltage is applied. Thereafter, heat and pressure are applied to the recording paper by the fixing device 906, and the transferred toner image is fixed. On the other hand, after the surface charge of the photosensitive drum 902 to which the toner has been transferred is removed by the charge removal device 907, the toner remaining on the surface is removed by the cleaning device 908 and is charged again by the charging device 901. Yes.

  In the image forming unit as described above, for example, the charging device 901, the photosensitive drum 902, the developing device 904, the charge eliminating device 907, and the cleaning device 908 are accommodated as a process unit 900 in an integrated cartridge that can be attached to and detached from the apparatus main body. . Thus, for example, when the maintenance is performed such that the photosensitive drum 902 is deteriorated or the toner is insufficient, the process unit 900 can be replaced as a unit, and the maintenance work is simplified.

  While the process unit 900 is mounted, the photosensitive drum 902 and the transfer roller 905 on the apparatus main body are in pressure contact with each other, but the process unit 900 is in the radial direction of the photosensitive drum 902 and away from the transfer roller 905. If the toner is removed, that is, if it is removed in the upward direction in the figure, the photosensitive drum 902 and the transfer roller 905 are less likely to rub when the process unit 900 is attached and detached, and the surface of the photosensitive drum 902 is scratched. It ’s hard to follow. In order to remove the process unit 900 in such a direction, an openable / closable cover is provided on the upper surface or side surface of the image forming apparatus, and the process unit 900 is attached and detached by opening the cover.

  In consideration of space saving and work convenience, it is preferable that the process unit 900 is accessible from the front side of the apparatus and can be attached and detached. However, in order to remove the process unit 900 from the front side of the image forming apparatus, the photosensitive drum 902 Since the process unit 900 is moved in the axial direction, that is, toward the front of the drawing, the transfer roller 905 needs to be separated from the photosensitive drum 902 in advance so that the surface of the photosensitive drum 902 is not damaged ( Patent Document 1). For example, in order to make the transfer roller 905 detachable in the direction of the arrow, it is conceivable to employ a configuration in which the transfer guide 909 that supports the transfer roller 905 can be moved in the direction of the arrow.

Japanese Patent Laid-Open No. 11-52814

  Some image forming apparatuses used in printers, facsimiles, copiers, and the like have a so-called C path as their conveyance path. The C path is a path in which the transport path from the paper feed cassette to the paper discharge tray has a substantially C shape. For example, in the image forming unit as shown in FIG. The recording sheet is conveyed from the upper side to the upper side, and the recording sheet is nipped by the photosensitive drum 902 and the transfer roller 905 arranged to face the left and right, and the toner image is transferred. In such a C-pass image forming apparatus, in order to enable the transfer guide to be moved to the side of the apparatus, the transfer guide is opened together with the side cover provided on the side of the apparatus so that the transfer roller is removed from the photosensitive drum. There is a configuration in which the process unit is taken out by opening the front cover from the front of the apparatus.

  In the image forming apparatus having such a configuration, the user erroneously operates the process unit for replacing the process unit and tries to take out the process unit without opening the side cover, that is, without separating the transfer roller from the photosensitive drum. In order not to damage the drum or the like, a configuration is adopted in which the front cover cannot be opened unless the side cover is opened. However, it is difficult to understand that the front cover cannot be opened unless the side cover is opened. In general, printers, facsimiles, copiers, and the like are used by many users in offices, and it is assumed that many users also perform maintenance such as paper jam clearance and toner replacement. If you are a user who has not read the manual, you may try to open it from the front cover, which is easy to operate, and it is difficult for various users to understand the work procedure of opening the side cover first and then opening the front cover. There is a problem that it is difficult.

  On the other hand, a configuration in which the opening / closing of the side cover and the movement of the transfer guide are independent is also conceivable, but considering the convenience of work when clearing a paper jam, the transfer guide is interlocked with the opening of the side cover as described above. A configuration is also possible in which the image forming unit is opened and the conveyance path near the image forming unit can be accessed. In addition, if the opening / closing operation of the side cover and the movement operation of the transfer guide are independent, the user may forget to return the transfer guide to the original state while being separated from the photosensitive drum, and close the side cover. It is assumed that even if the image forming apparatus is operated in a state where the photosensitive drum and the transfer roller are not in pressure contact with each other, image formation cannot be performed, and a paper jam may occur.

  The present invention has been made to solve such a problem, and in order to insert and remove a process unit including a photosensitive drum from the front side of the apparatus without damaging the photosensitive drum or the like, the transfer roller can be simply and space-saving. It is an object of the present invention to provide a means that can contact and separate from the photosensitive drum and facilitates access to the conveyance path near the photosensitive drum from the side of the apparatus in order to eliminate a paper jam.

  Another object of the present invention is to provide means for preventing the user from closing the side cover of the apparatus main body in a state where the transfer roller is separated from the photosensitive drum.

  The present invention relates to a process unit including a photosensitive drum in an image forming apparatus for forming an image by nipping a recording paper between a photosensitive drum and a transfer roller and transferring a toner image on the surface of the photosensitive drum to the recording paper. However, a transfer guide provided so as to be able to be inserted and removed from the front side of the apparatus in the axial direction of the photosensitive drum and pivotally supporting the transfer roller so as to be in pressure contact with the photosensitive drum is connected and separated between the transfer roller and the photosensitive drum. The transfer guide is provided at a pressure contact position where the transfer roller is in pressure contact with the photosensitive drum by being in contact with the transfer guide. A holding member that holds and releases the corresponding contact so that the transfer roller can be tilted to a retracted position where the transfer roller is separated from the photosensitive drum. An operation member provided to be movable between the contact position and the release position and for moving the holding member to the contact position and the release position is provided on the side cover so as to be operable from the front side of the apparatus. Features.

  In the present invention, the holding member holds the transfer guide in a pressure contact position by contacting the vicinity of the tilting tip of the back surface of the guide surface on which the transfer roller is provided in the transfer guide. Further, the present invention is characterized in that it is provided so as to be rotatable in the vicinity of the tilting front end portion on the back surface side and moves between the contact position and the release position.

  In the present invention, the operation member having the holding member as a contact position can be passed on the rotation track of the operation member that rotates as the side cover is opened and closed, and the holding member is set to the release position. It is characterized in that a restricting member that prevents the operation member from passing is provided.

  Further, the present invention guides the operation member that rotates as the side cover is opened with the holding member in the release position so that the holding member rotates toward the contact position. And a guide that allows the regulating member to pass therethrough.

  According to the image forming apparatus of the present invention, the process unit including the photosensitive drum is provided so as to be insertable / removable in the axial direction of the photosensitive drum from the front side of the apparatus, and the transfer roller can be pressed against the photosensitive drum. A transfer guide that supports the shaft is tiltable in a direction in which the transfer roller and the photosensitive drum come in contact with and away from each other, and is provided to open and close together with a side cover provided on a side surface of the apparatus. A holding member that holds the transfer guide at a pressure contact position where the transfer roller comes into pressure contact with the photosensitive drum and releases the corresponding contact so that the transfer roller can tilt to a retracted position where the transfer roller is separated from the photosensitive drum. The side cover is provided movably between a contact position and a release position, and an operation member for moving the holding member to the contact position and the release position is provided on the side cover. Since it is provided so that it can be operated from the front side of the device, the operation unit is operated from the front side of the device without opening the side cover, and the transfer guide is tilted to the retracted position so that the process unit can be exposed without damaging the photosensitive drum. Can be inserted and removed in the axial direction of the body drum. Further, since the transfer guide is opened and closed together with the side cover, access to the vicinity of the photosensitive drum is easy.

  Further, according to the present invention, the holding member is held at the pressure contact position by contacting the holding member with the vicinity of the tilting tip portion on the back side of the guide surface provided with the transfer roller in the transfer guide. In addition, the holding member can be configured in a simple and space-saving manner because it is provided so as to be rotatable in the vicinity of the tilting tip portion on the back surface side and moves between the contact position and the release position.

  Further, according to the present invention, the operation member having the holding member as a contact position can be passed on the rotation track of the operation member that rotates as the side cover is opened and closed, and the holding member is moved to the release position. Therefore, when the side cover is closed with the holding member as the release position, the operation member cannot pass through the restriction member, and the side cover cannot be closed. Thereby, it is possible to prevent the side cover from being closed while the transfer guide is in the retracted position.

  According to the present invention, the operation member that rotates as the side cover is opened in a state where the holding member is in the release position is configured so that the holding member rotates toward the contact position. Since the guide that guides and allows the passage of the restricting member is provided, when the side cover is opened with the holding member as the release position, the guide is moved to a position where the holding member can pass. Accordingly, the side cover can be opened regardless of the position of the operation member, and only the side cover can be prevented from being closed with the transfer guide in the retracted position.

  FIG. 1 is a schematic perspective view showing the appearance of a copy / facsimile multifunction peripheral 100 equipped with an image forming apparatus according to an embodiment of the present invention. As shown in FIG. An image reading unit 101 functioning as a bed scanner, an operation panel 102 for inputting image reading and recording start, a main body 103 incorporating an image forming apparatus for forming an image on recording paper, and the recording paper And a paper feed cassette 104 to be supplied. The copier / facsimile multifunction peripheral 100 is provided with a front cover 30 on the front surface of the main body 103, that is, the surface on which the operation panel 102 is provided, and a jam access cover (side cover) 31 on the right side surface. The inside of the main body 103 can be accessed by opening the jam access cover 31.

  FIG. 2 is a schematic cross-sectional view showing the internal configuration of the main body 103 and the paper feed cassette 104 constituting the image forming apparatus in the copy / facsimile multifunction peripheral 100. As shown in the figure, a paper feed cassette 104 for sequentially supplying recording paper is disposed at the bottom of the apparatus, an image forming unit 105 is disposed above the paper feed cassette 104, and a paper discharge tray is further disposed above it. 106 is arranged. A conveyance path 107 for conveying recording paper from the paper feed cassette 104 to the paper discharge tray 106 extends upward from one end side of the paper feed cassette 104 to the image forming unit 105 and further extends upward. Then, it is formed so as to bend in the horizontal direction and lead to the paper discharge tray 106. Although not shown in the drawing, the image reading unit 101 and the operation panel 102 are disposed above the paper discharge tray 106.

  The paper feed cassette 104 has a box shape capable of storing recording papers of various sizes, and is provided at the bottom of the apparatus so as to be able to be drawn out, so that recording papers can be loaded as needed. Inside the paper feed cassette 104, a guide 40 for holding recording paper of a predetermined size at the paper feed position is disposed. The guide 40 is provided so as to be swingable within a predetermined range, and its bottom plate is biased upward by a spring or the like (not shown), thereby holding a plurality of recording sheets in a stacked state, One end of the uppermost paper is always positioned at the paper feed position. A paper feed roller 41 and a separation pad 42 are provided at the paper feed position, and the uppermost paper positioned at the paper feed position by the guide 40 is in pressure contact with the paper feed roller 41. The paper feed roller 41 is formed by fixing a roller made of silicon and EPDM (Ethylene-Propylene-Diene Methylene Linkage) to a metal roller shaft, for example, and is the top paper. The recording sheet is fed into the conveyance path 107 by rotating while being pressed against the sheet. The separation pad 42 has a friction coefficient with respect to the recording paper that is lower than the friction coefficient with respect to the recording paper of the paper feed roller 41 and higher than the friction coefficient between the recording papers, and can be formed of, for example, urethane resin. Such a separation pad 42 is disposed below the paper feed roller 41 so as to be movable up and down and is urged upward by a spring (not shown). The recording paper that is pressed against the roller surface and passes through the pressed portion is separated and fed one by one by friction.

  As shown in FIGS. 2 and 3, the image forming unit 105 includes a charging device 52, an LED head 53, a developing device 54, a transfer roller 55, and a cleaning device 56 disposed around the photosensitive drum 51, and a photosensitive device. The fixing device 57 is disposed in the conveyance path 107 on the downstream side of the body drum 51. Among these, the photosensitive drum 51, the charging device 52, the developing device 54, and the cleaning device 56 are housed in a cartridge as a process unit 50 and integrated.

  The photoconductive drum 51 has a photoconductive film formed of an organic photoconductor formed on the surface thereof, is rotated at a predetermined speed by a motor, and is charged to a constant voltage by a charging device 52. The charging device 52 is a non-contact corona charging method called a so-called scorotron charger, and although not shown in detail in the drawing, a discharge wire is disposed at substantially the center of a casing electrode forming a half space. In addition, a grid electrode is disposed on the photosensitive drum 51 side, and a corona discharge is generated when a predetermined voltage is applied to the discharge wire, and the amount of ions due to the corona discharge is controlled by the grid electrode. . The charging device 52 may employ another charging device such as a contact roller charging method instead of the non-contact corona charging method.

  The LED head 53 is a so-called self-luminous printer head in which LED arrays are arranged in parallel for the number of recording pixels, and light emitted from the LED array is imaged on the surface of the photosensitive drum 51 by a Selfoc lens array. The surface of the photosensitive drum 51 is selectively exposed to the photosensitive drum 51 based on image information, and an electrostatic latent image is formed on the surface. The surface of the photosensitive drum 51 charged by the charging device 52 is attenuated by being exposed by the LED head 53, and an electrostatic latent image is formed by the potential difference from the unexposed portion. As the image information, for example, an image of a document read by the reading table 101 functioning as a flatbed scanner is transmitted to the LED head 53 as an electrical signal. As the exposure device, a scanning optical system using a semiconductor laser in addition to the LED head 53 may be adopted.

  The developing device 54 includes a supply roller 58, a developing roller 59, and a toner container 60. The toner is generated by a difference in bias voltage applied to the supply roller 58 and the developing roller 59 from an electric circuit (not shown). The toner in the container 60 is supplied to the developing roller 59 through the supply roller 58, and a toner layer is formed on the surface of the developing roller 59. The developing roller 59 on which the toner layer is formed is rotated at a position close to the photosensitive drum 51, and the toner on the developing roller 59 moves to the photosensitive drum 51 due to a potential difference from the electrostatic latent image on the photosensitive drum 51. A toner image is formed on the surface of the photosensitive drum 51 based on the electrostatic latent image. Such a developing device 54 is an example, and selection of magnetic toner or non-magnetic toner, selection of contact development method or non-contact development method, and the like are arbitrary.

  The transfer roller 55 is a roller made of EPDM foam or urethane sponge, and is pressed against the photosensitive drum 51 at a position facing the conveyance path 107 so that a bias voltage is applied from an electric circuit (not shown). Yes. A toner image formed on the surface of the photosensitive drum 51 is applied by applying a bias voltage by nipping the recording paper supplied from the paper feeding cassette 104 through the conveying path 107 by the photosensitive drum 51 and the transfer roller 55. Is transferred to the recording paper.

  The cleaning device 56 is a cleaning blade pressed against the photosensitive drum 51 after transfer, and applies a constant voltage from an electric circuit (not shown) to remove toner and paper dust remaining on the surface of the photosensitive drum 51. The electrostatic latent image is erased while being removed. As a result, the surface of the photosensitive drum 51 is cleaned and continuous use is possible. As the cleaning device, other contact type or non-contact type using a cleaning roller or the like can be adopted, and a cleaningless type without using the cleaning device 56 can be adopted.

  The fixing device 57 includes a heating roller 62 and a pressure roller 63 disposed respectively at positions opposed to the conveyance path 107, and fixes the toner image on the recording paper conveyed through the conveyance path 107 by heating and pressing. is there. The surface of the heating roller 62 is maintained at a predetermined temperature by a heater, and a pressure roller 63 is pressed against the heating roller 62 with a predetermined pressure. The recording sheet on which the toner image has been transferred is nipped between the heating roller 62 and the pressure roller 63 so that the toner on the recording sheet is melted and fixed. The image forming unit 105 configured as described above forms an image of a document read by the reading table 101 on a recording sheet.

  As shown in FIG. 2, the recording sheet is conveyed from the sheet feeding cassette 104 along the conveying path 107 to the image forming unit 105 configured as described above, and the recording sheet on which an image is formed by the image forming unit 105. Is discharged to the discharge tray 106. The conveyance path 107 extends substantially upward from the paper feed cassette 104 to the image forming unit 105, and a pair of registration rollers 70 and 71 for adjusting the conveyance posture of the recording paper is provided in the middle. It has been. The registration rollers 70 and 71 are configured such that a rotation force from a driving source such as a motor is transmitted to a roller shaft, and the pair of registration rollers 70 and 71 are disposed at opposite positions of the conveyance path 107. It is arrange | positioned so that it may press-contact with the roller surface of this. The leading edge of the recording sheet conveyed from the sheet feeding cassette 104 toward the image forming unit 105 comes into contact with the registration rollers 70 and 71. Although not shown in the drawing, a sensor is provided on the upstream side of the registration rollers 70 and 71, and the registration rollers 70 and 71 are rotated after a predetermined time has elapsed since the sensor detected the recording paper. Therefore, since the registration rollers 70 and 71 are stopped when the leading edge of the recording paper comes into contact, the recording paper is bent at the leading edge so that the entire area of the leading edge is in contact with the roller surface of the registration rollers 70 and 71. Abut. Thereby, the skew of the recording sheet is corrected. Thereafter, the recording paper is nipped by the rotation of the registration rollers 70 and 71 and conveyed to the image forming unit 105. A conveyance roller 72 is appropriately provided in the conveyance path 107 between the image forming unit 105 and the paper discharge tray 106, and the recording paper on which an image is formed is conveyed by the conveyance roller 72 and discharged to the paper discharge tray 106. Is done. A C path is formed from the paper feed cassette 104 to the paper discharge tray 106 by such a conveyance path 107.

  As described above, the photosensitive drum 51, the charging device 52, the developing device 54, and the cleaning device 56 are housed and integrated as a process unit 50 in, for example, a synthetic resin cartridge. However, as shown in FIG. 3, the photosensitive drum 51 and the transfer roller 55 are in pressure contact with each other as shown in FIG. In order to prevent the photosensitive drum 51 from being damaged, it is necessary to separate the photosensitive drum 51 and the transfer roller 55 from each other. Hereinafter, a structure for tilting the transfer guide 73 to separate the photosensitive drum 51 and the transfer roller 55 will be described in detail. However, the tilt mechanism of the transfer guide 73 shown in the present embodiment is an example, and The configuration for tilting the transfer guide can be changed without changing the gist of the invention.

  The process unit 50 is supported by a frame or the like of the main body 103 and can be held at a predetermined position in the main body 103, and can be inserted and removed in the axial direction of the photosensitive drum 51 from the front side of the main body 103. On the other hand, the transfer roller 55 is rotatably supported by a transfer guide 73 that constitutes a part of the conveyance path 107, and the transfer guide 73 is in a direction in which the photosensitive drum 51 and the transfer roller 55 come into contact with and separate from each other. It can be tilted. That is, in FIG. 3, the process unit 50 can be pulled out and removed from the front side of the figure from the state where it is mounted on the main body 103, and the transfer guide 73 can be tilted to the right side of the figure when the process unit 50 is inserted or removed. The transfer guide 73 is formed from a synthetic resin or a metal plate, and forms a guide surface in the width direction of the transport path 107 in the transport path 107 on the opposite side of the process unit 50, and is provided on the lower end side thereof. The supported spindle 74 is supported by a conveyance guide 75 constituting the conveyance path 107, and as shown in FIG. 4, a pin 76 provided on the upper end side of the support shaft 74 is inserted into a guide hole 77 of the conveyance guide 75, and a predetermined range Thus, it can be tilted toward the side surface of the main body 103, in the drawing, toward the jam access cover 31. Further, the transfer guide 73 pivotally supports the transfer roller 55 and one registration roller 70 so as to be opposed to the photosensitive drum 51 and the other registration roller 71, respectively, as shown in FIG. Springs 78 and 79 are provided at the respective bearing portions (not shown) to urge the transfer roller 55 and the registration roller 70 toward the photosensitive drum 51 and the registration roller 71, respectively.

  3 and 4, the conveyance guide 75 that supports the transfer guide 73 is supported by the jam access cover 31, and when the jam access cover 31 is opened as shown in FIG. Both the guide 73 and the conveyance guide 75 are also opened so that a paper jam can be removed by accessing the vicinity of the image forming unit 105 from the side of the main body 103. Note that the transfer guide 73 may be directly supported by the jam access cover 31 instead of the conveyance guide 75.

  Further, as shown in FIG. 3, a contact portion 80 is formed at the tip end of the transfer guide 73 on the back surface side so as to contact a latch (holding member) 81 provided in the vicinity of the contact portion 80. It has become. As shown in FIGS. 3 and 4, the latch 81 has a radial direction from a rotary shaft 82 rotatably supported by the conveyance guide 75 in the vicinity of the contact portion 80 with the width direction of the transfer guide 73 as an axial direction. Is a flat plate-like member provided at a predetermined interval so as to protrude into the shaft, and can be rotated together with the rotary shaft 82. Further, as shown in FIG. 4, an operation lever (operation member) 83 is provided at one end of the rotation shaft 82 on the front side of the main body 103. The operating lever 83 is for rotating the rotary shaft 82 to rotate the latch 81, and protrudes from the rotary shaft 82 in the radial direction so as to be in the same direction as the latch 81.

  As shown in FIG. 3, the leading end of the latch 81 abuts against the abutting portion 80 of the transfer guide 73, so that the transfer roller 55 is in pressure contact with the photosensitive drum 51, that is, in the pressure contact position. Is supposed to hold. FIG. 6 is an enlarged cross-sectional view in the vicinity of the contact portion 80. The contact portion 80 is formed by recessing the back surface of the transfer guide 73. As shown in the drawing, the contact surface 80a and the regulating surface are shown. It consists of 80b and the bulging part 80c. The contact surface 80a is for preventing the transfer guide 73 from tilting to the retracted position by contacting the front end surface 81a of the latch 81, and as shown in the figure, the transfer guide 73 is in the pressure contact position. The surface is substantially perpendicular to the surface. The regulating surface 80 b is a substantially horizontal surface formed so as to protrude from the upper side of the contact surface 80 a toward the latch 81, and is in contact with the surface 81 b of the latch 81 that is in the radial direction with respect to the rotation shaft 82. The latch 81 is restricted from rotating clockwise beyond the contact portion 80. Further, in order to allow the latch 81 to rotate counterclockwise from the contact portion 80, the lower side of the contact surface 80a is opened so as not to contact the latch 81, but the corresponding contact surface 80a. A bulging portion 80c is formed on the lower side, and a latch 81 is locked to the contact portion 80 to prevent the latch 81 from rotating inadvertently and to contact the contact portion 80. When it is positioned like this, it gives a click feeling. The bulging portion 80c slightly bulges from the lower side of the abutting surface 80a in a substantially horizontal direction, and the latch 81 is separated from the abutting portion 80 beyond the bulging portion 80c as shown in the figure. For example, it is preferable to form the bulging portion 80c of an elastic member such as rubber because the operation feeling of the latch 81 is good.

  Further, as shown in FIG. 4, when the latch 81 is in contact with the contact portion 80, the pin 76 provided on the upper end side of the transfer guide 73 is the left end of the guide hole 77, that is, on the photosensitive drum 51 side. And is not allowed to tilt further toward the photosensitive drum 51 side. As shown in FIG. 5, when the transfer guide 73 together with the jam access cover 31 is opened to the side, the transfer roller 55 and the registration roller 70 are separated from the photosensitive drum 51 and the registration roller 71, respectively, and the pressing force from them is reduced. However, since the transfer guide 73 cannot be further tilted toward the photosensitive drum 51 as described above, the transfer guide 73 can be opened and closed together with the jam access cover 31 while holding the transfer guide 73 in the press contact position.

  On the other hand, as shown in FIG. 7, the transfer guide 73 can be tilted to the retracted position when the latch 81 is rotated counterclockwise and its tip is separated from the contact portion 80. Such a position of the latch 81 is referred to as a release position. As described above, the transfer roller 55 and the registration roller 70 at the pressure contact position are urged toward the photosensitive drum 51 or the registration roller 71 by the springs 78 and 79, respectively, so that the holding by the latch 81 is released. As a result, the biasing force becomes a reaction force, and the transfer guide 73 tilts toward the retracted position. Further, as shown in the drawing, a tension spring 87 is provided between the transfer guide 73 and the conveyance guide 75, and the transfer guide 73 in a tiltable state is reliably retracted by the biasing force of the tension spring 87. Tilt to position. Thereby, the transfer roller 55 can be separated from the photosensitive drum 51, and the process unit 50 can be pulled out in the axial direction of the photosensitive drum 51, that is, the front side in the figure without damaging the photosensitive drum 51. As shown in the figure, the process unit 50 is provided with an openable / closable shutter 64 that covers the surface of the photosensitive drum 50, and a shutter pushing portion (not shown) for opening and closing the shutter 64 on the transfer guide 73. If the transfer guide 73 is separated and the shutter 64 is closed, and the transfer guide 73 is close, the shutter 64 is opened. The surface is covered with the shutter 64, so that it is possible to prevent other members from touching or touching by mistake by the user or the like.

  Further, when the latch 81 is rotated clockwise from the release position to the contact position, the leading end of the latch 81 comes into contact with the transfer guide 73 at the retracted position, and the latch 81 is rotated as the latch 81 rotates. The transfer guide 73 is tilted from the retracted position to the pressure contact position so that the front end presses the back surface of the transfer guide 73. As shown in FIG. 6, the latch 81 comes into contact with the contact portion 80 of the transfer guide 73, and as shown in FIG. 3, the transfer guide 73 can be positioned at the press contact position.

  The rotation of the latch 81 to the contact position and the release position can be performed by the operation lever 83 as described above, and the operation lever 83 is provided on the front side of the main body 103 as shown in FIG. If the front cover 30 (not shown) of the main body 103 is opened, it can be operated from the front side of the apparatus. Therefore, in order to tilt the transfer guide 73, that is, when the process unit 50 is inserted or removed, the photosensitive drum 51. Therefore, it is not necessary to open the jam access cover 31 in order to separate the transfer roller 55 from the paper. Further, as shown in FIG. 8A, the distal end side of the operation lever 83 with the latch 81 in the contact position extends so as to overlap the process cartridge 50 on the insertion / extraction side, that is, the front side of the apparatus. When the lever is pivoted downward to pivot to the release position, the distal end side of the operation lever 83 is positioned so as not to overlap the process cartridge 50. Thus, it is clear from the appearance that if the latch 81 is in the contact position, the operation lever 83 interferes and the process cartridge 50 cannot be extracted. To extract the process cartridge 50, the latch 81 is in the release position. Thus, the user can intuitively understand that the operation lever 83 must be operated.

  As shown in FIG. 5, the transfer guide 73 opens and closes together with the jam access cover 31. However, the copy access and facsimile machine is closed by closing the jam access cover 31 with the transfer guide 73 in the retracted position. When 100 is operated, since the transfer roller 55 is separated from the photosensitive drum 51, image formation cannot be performed on the recording paper, and there is a risk of paper jamming in the vicinity of the image forming unit 105. In order to prevent this, as shown in FIG. 4, a slit (regulating member) 84 through which the operation lever 83 that rotates as the jam access cover 31 opens and closes is provided on the side of the operation lever 83. ing.

  As shown in FIG. 4, the slit 84 is provided on a turning locus in which the operation lever 83 rotates with the opening of the jam access cover 31 with respect to the operation lever 83 in a state where the jam access cover 31 is closed. In addition, a predetermined position of a slit plate 85 protruding in the horizontal direction from a frame of the main body 103 (not shown) is formed by cutting out in the horizontal direction. The width of the slit 84 is set in relation to the shape of the operation lever 83. Specifically, as shown in FIG. 8A, the slit 84 rotates with the latch lever 81 in the contact position, that is, with the jam access cover 31 closed as shown. The operation lever 83 protruding from the shaft 82 in a substantially horizontal direction can pass through when it is rotated together with the jam access cover 31, and the width of the slit 84 is sufficiently larger than the thickness of the operation lever 83. Therefore, when the latch 81 is in the contact position, that is, when the transfer guide 73 is in the pressure contact position, the operation lever 83 can pass through the slit 84 so that the jam access cover 31 can be arbitrarily opened and closed. It has become.

  On the other hand, as shown in FIG. 8 (b), the slit 84 extends from the rotary shaft 82 in a state in which the jam access cover 31 is closed as shown in FIG. The operation lever 83 that protrudes substantially downward cannot pass through when it is rotated together with the jam access cover 31, and the width of the slit 84 is smaller than the length of the operation lever 83 in the longitudinal direction. Therefore, when the latch 81 is in the release position, that is, when the transfer guide 73 is in the retracted position, the operation lever 83 cannot pass through the slit 84, and even if the jam access cover 31 is to be closed, as shown in FIG. In addition, the operation lever 83 is brought into contact with the slit 84 and cannot be completely closed.

  Further, as shown in FIG. 4, a guide 86 for guiding the operation lever 83 is provided inside the slit 84. The guide 86 is a flat plate projecting from the slit plate 85 on the lower side of the slit 84 toward the inside of the apparatus, and guides the operation lever 83 at the upper end edge thereof. As shown in FIG. 4, the upper edge of the guide 86 extends substantially horizontally from the lower edge of the slit 84 and then descends obliquely downward. The guide 86 guides the operation lever 83 to pass through the slit 84 when the jam access cover 31 is opened with the latch 81 as the release position.

  Specifically, as shown in FIG. 9A, when the jam access cover 31 is opened with the latch 81 as the release position, the operation lever 83 comes into contact with the guide 86, and the jam access cover 31 is further opened to open the operation lever. 83 moves along with the jam access cover 31 along the upper edge of the guide 86 while rotating from the position where the latch 81 is set to the release position to the contact position side. As shown in FIG. 9B, when passing through the slit 84, the operation lever 83 is guided by the guide 86 and further rotated so that it can pass through the slit 84. Thus, by providing the guide 86, when the jam access cover 31 is opened, the operation lever 83 can pass through the slit 84 regardless of whether the latch 81 is in the contact position or the release position. Become. On the other hand, when closing the jam access cover, as shown in FIG. 8B, the operation lever 83 in the state where the latch 81 is in the release position cannot pass through the slit 84. Accordingly, the jam access cover 31 can be opened regardless of the position of the operation lever 83, and it is possible to prevent the jam access cover 31 from being closed only when the transfer guide 73 is in the retracted position. In addition, the guide 86 does not necessarily have to guide the operation lever 83 with the latch 81 in the release position so as to rotate until the latch 81 is in the contact position, but the guide 86 brings the latch 81 into the contact position. If the operating lever 83 is guided so as to be positioned, it is preferable that the operating lever 83 can pass through the slit 84 even when the jam access cover is subsequently closed.

  In the present embodiment, the embodiment in which the image forming apparatus is implemented as the copy / facsimile multifunction peripheral 100 has been described. However, the image forming apparatus is not limited to the copy / facsimile multifunction peripheral 100, and may be a single machine, a printer, or the like. Of course, the embodiment can be changed without departing from the gist of the invention. In the present embodiment, the slit 84 is described as an example of the member that restricts the rotation of the operation lever 83. However, the restriction member according to the present invention is not limited to the slit 84, and the shape of the operation member. Therefore, the operation member having the holding member as the contact position can be passed and the operation member having the holding member as the release position can be passed.

1 is a schematic perspective view showing an external configuration of a copy / facsimile multifunction peripheral 100 according to an embodiment of the present invention. 2 is a schematic cross-sectional view showing a configuration inside a main body 103 of the copy / facsimile multifunction peripheral 100. FIG. FIG. 4 is an enlarged view showing a configuration in the vicinity of a process unit 50 in a state in which a photosensitive drum 51 and a transfer roller 55 are pressed against each other. FIG. 4 is a schematic perspective view showing the configuration of a jam access cover 31, a transfer guide 73, an operation lever 83, a slit 84, and the like. FIG. 4 is an enlarged view showing a configuration in the vicinity of a process unit 50 in a state where a jam access cover 31 is opened. 3 is an enlarged view showing a detailed configuration of a contact portion 80. FIG. FIG. 4 is an enlarged view showing a configuration in the vicinity of a process unit 50 in a state where a transfer guide 73 is tilted to a retracted position. (A) is a figure for demonstrating the state in which the operation lever 83 can pass the slit 84, (b) is a figure for demonstrating the state in which the operation lever 83 cannot pass the slit 84. FIG. FIG. 10 is a view for explaining a state in which an operation lever 83 is guided by a guide 86 and passes through a slit 84. It is a schematic diagram which shows an example of the conventional image forming apparatus.

Explanation of symbols

31 Jam access cover (side cover)
50 Process unit 51 Photosensitive drum 55 Transfer roller 73 Transfer guide 81 Latch (holding member)
83 Operation lever (operation member)
84 Slit (Regulator)
86 Guide 100 Copier / Facsimile MFP (image forming device)

Claims (4)

In an image forming apparatus for forming an image by nipping a recording sheet between a photosensitive drum and a transfer roller and transferring a toner image on the surface of the photosensitive drum to the recording sheet.
A process unit including a photosensitive drum is provided so as to be insertable / removable in the axial direction of the photosensitive drum from the front side of the apparatus,
A transfer guide that pivotally supports the transfer roller so as to be in pressure contact with the photosensitive drum can tilt in a direction in which the transfer roller and the photosensitive drum come into contact with and separate from each other, and opens and closes together with a side cover provided on a side surface of the apparatus. Provided to
Abutting on the transfer guide, the transfer guide holds the transfer guide at a pressure contact position where the transfer roller presses against the photosensitive drum, and releases the contact, and the transfer roller tilts to a retracted position where the transfer roller is separated from the photosensitive drum. A holding member to be enabled is provided on the side cover so as to be movable between a contact position and a release position,
An image forming apparatus, wherein an operation member for moving the holding member to a contact position and a release position is provided on the side cover so as to be operable from the front side of the apparatus.   The holding member holds the transfer guide in a pressure contact position by contacting the vicinity of the tip end of the back side of the guide surface on which the transfer roller is provided in the transfer guide. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided so as to be rotatable in the vicinity of the front end portion and moves between a contact position and a release position.   The operation member having the holding member as a contact position is allowed to pass on the rotation track of the operation member that is rotated as the side cover is opened and closed, and the operation member having the holding member as a release position cannot be passed. The image forming apparatus according to claim 1, wherein a regulating member is provided.   The operation member, which rotates as the side cover is opened with the holding member in the release position, is guided so that the holding member rotates to the contact position side, and passes through the regulating member. The image forming apparatus according to claim 3, further comprising a guide that enables the image forming apparatus.

Images