JP2010128186A - Contact/separation device for contact/separation member, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact/separation device for a contact/separation member, the device being used in an image forming apparatus such as a copying machine, facsimile, or printer, which brings the contact/separation member, such as a transfer member or cleaning member, into contact with an image carrier such as a photoreceptor or separates the member therefrom, decreasing load on elements composing the image forming apparatus, and reducing consumption energy of the apparatus, and to provide an image forming apparatus having the device. <P>SOLUTION: The device includes: a support member 83 supporting the contact/separation member 66 so that it is brought into contact with/separated from the image carrier 11; a locking member 89 that locks the support member 83, with the contact/separation member 66 abutting on the image carrier 11; a pressing means 81 connected to the locking member 89 and used for bringing the contact/separation member 66 into pressure-contact with the image carrier 11 via the locking member 89 and support member 83, with the support member 83 locked by the locking member 89; and a locking/unlocking means 90 for bringing about a locking/unlocking state. Input from the pressing means 81 to the locking/unlocking means 90 is stopped in a locking state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a contacting / separating device for use in an image forming apparatus such as a copying machine, a facsimile, a printer, and the like, in which an contacting / separating member such as a transfer member or a cleaning member is brought into contact with or separated from an image carrier such as a photosensitive member. The present invention relates to such an image forming apparatus.

  An image forming apparatus such as a copying machine, a facsimile machine, a printer, or the like provided with an image carrier such as a photosensitive member, which is arranged so as to be in contact with the image carrier and transfers the image carried on the image carrier onto a transfer sheet or the like There is known an image forming apparatus including a transfer member such as a transfer roller and a cleaning member such as a cleaning brush which is disposed so as to contact the image carrier and cleans the image carrier (for example, [Patent Document 1] to [See Patent Document 5]). In general, such an image forming apparatus has a spring for elastically contacting the transfer member, the cleaning member, and the like with the image carrier at a predetermined pressure (for example, [Patent Document 1] to [Patent Document 1] Reference 3]).

  In such an image forming apparatus, for example, in order to adjust the density and color of a formed image, there is a case where a control called process control is performed in which a pattern image is formed on an image carrier and read by a predetermined sensor. When such control is performed, it is necessary to maintain the state in which the image is carried on the image carrier. However, if a transfer member, a cleaning member, or the like on the image carrier is in contact, the image carried on the image carrier is disturbed. For these reasons, there is known an image forming apparatus provided with a contact / separation member contacting / separating device for contacting / separating the transfer member, the cleaning member, etc. against the image carrier against the biasing force of the spring. (For example, see [Patent Document 1] and [Patent Document 2]).

  Such contact / separation member contact / separation devices generally include an arm-shaped member that supports the contact / separation member, and a cam that is always engaged with the member and swings the arm-shaped member by its rotation to contact / separate the contact / separation member with the image carrier. And a motor for rotating the cam (for example, see [Patent Document 1] and [Patent Document 2]).

JP 2003-131494 A Japanese Patent No. 3567424 JP 2007-328275 A JP 2006-227660 A JP 2007-322786 A

  However, in such a configuration, there is a problem that a load due to a spring is always applied to the motor or the like and is likely to deteriorate over time. Further, in such a configuration, a technique has been proposed that exhibits a predetermined function by maintaining the phase of the cam at a predetermined phase (see, for example, [Patent Document 1]). When the motor is input to the motor as a rotational load, there is a problem that the deterioration of the motor is more likely to occur, and it is necessary to maintain power supply to the motor in order to maintain the phase against the rotational load. In some cases, the energy consumption is large.

  The present invention relates to a contact / separation member contact / separation device for use in an image forming apparatus such as a copying machine, a facsimile, or a printer, in which a contact member such as a transfer member or a cleaning member is contacted / separated with an image carrier such as a photoconductor. The present invention relates to a contact / separation member contacting / separating device capable of reducing a load on elements constituting the same and reducing energy consumption thereof and an image forming apparatus having the same.

  In order to achieve the above object, an invention according to claim 1 is directed to a support member that supports a contact / separation member that is contacted / separated to / from an image carrier so as to be able to contact / separate to / from the image carrier, and A locking member for locking the support member in contact with the locking member; and the locking member and the support member that are connected to the locking member and locked by the locking member. A pressurizing unit that presses the contact / separation member against the image carrier, and an engagement / disengagement unit for forming or releasing the engagement state, and the engagement state is released by the engagement / disengagement unit. Is released, the pressure contact by the pressure means is released, the contact / separation member is separated from the image carrier, and at least the locking state is formed, the engagement / disengagement means from the pressure means The input / output to the contact / separation device is stopped.

  According to a second aspect of the present invention, in the contacting / separating member contacting / separating device according to the first aspect, the engaging / disengaging means includes a connecting member swingably connected to the support member and the locking member, and at least the engaging member. A holding member that holds the posture of the connecting member so as to engage with the connecting member in a stopped state and maintain the locked state; and a driving unit that drives the holding member to form or release the locked state It is characterized by having.

  According to a third aspect of the present invention, in the contacting / separating member contacting / separating device according to the second aspect, the pressurizing unit is configured to drive the holding member by the driving unit at least in a state where the locked state is formed. The input to the driving means from is stopped.

  According to a fourth aspect of the present invention, in the contacting / separating member contacting / separating device according to any one of the first to third aspects, the engagement / disengagement means has a force that is large enough to maintain the locked state in the locked state. And urging means for urging in the direction in which the locked state is released.

  According to a fifth aspect of the present invention, in the contacting / separating member contacting / separating device according to any one of the first to fourth aspects, the locked state is maintained by a force large enough to maintain the locked state in the locked state. It is characterized by having contact / separation member support means for supporting the contact / separation member so that the weight of the contact / separation member works in the released direction.

  According to a sixth aspect of the present invention, in the contacting / separating member contacting / separating device according to any one of the first to fifth aspects, the pressurizing unit is configured such that the locking state is formed by the engaging / disengaging unit. The locking member is biased so as to maintain this state, and when the locking state is released by the engaging / disengaging means, the locking member is biased so as to maintain this state. To do.

  According to a seventh aspect of the present invention, in the contacting / separating member contacting / separating device according to any one of the first to sixth aspects, the contacting / separating member is a transfer member for transferring an image on the image carrier. It is characterized by.

  The invention according to claim 8 is the contacting / separating member contacting / separating device according to any one of claims 1 to 7, when jamming is detected by the jam detecting means for detecting occurrence of jamming and / or image adjustment. The locking state is released when the image for the image is carried on the image carrier.

  According to a ninth aspect of the present invention, there is provided an image forming apparatus comprising the contacting / separating member contacting / separating device according to any one of claims 1 to 8 and an image carrier on which the contacting / separating member contacts / separates.

  The present invention relates to a support member that supports a contact / separation member that is contacted / separated to / from the image carrier so that the contact / separation member can be contacted / separated to the image carrier, and locks the support member in a state where the contact / separation member contacts the image carrier A locking member for connecting to the image bearing member via the locking member and the support member in a locked state coupled to the locking member and locked by the locking member. A pressurizing means for pressing the member; and an engagement / disengagement means for forming or releasing the engagement state. When the engagement state is released by the engagement / disengagement means, The contact / separation member contact / separation in which the input from the pressurizing means to the engagement / disengagement means stops in the state where the pressure contact is released and the contact / separation member is separated from the image carrier and at least the locked state is formed. Since it is in the device, the load on the engaging / disengaging means by the pressurizing means is reduced. The contact / separation member contact / separation can suppress deterioration of the means over time, reduce energy consumption in the engagement / disengagement means, and prevent disturbance of the image on the image carrier and contribute to good image formation. An apparatus can be provided.

  The engaging / disengaging means is connected to the supporting member and the connecting member swingably connected to the engaging member so as to engage with the connecting member and maintain the engaging state at least in the engaging state. If the holding member that holds the posture of the member and the driving means that drives the holding member to form or release the locking state can be realized by a relatively simple configuration, By reducing the load on the engagement / disengagement means by the means, it is possible to suppress the deterioration of the engagement / disengagement means over time, and it is possible to reduce the energy consumed by the engagement / disengagement means and to prevent the disturbance of the image on the image carrier. Therefore, it is possible to provide a contact / separation member contact / separation device that can contribute to good image formation.

  If the input to the drive means from the pressurizing means in the direction of driving the holding member by the drive means stops at least in the state where the locked state is formed, a relatively simple configuration By reducing the load on the driving means and the holding member by the pressurizing means, it is possible to suppress the deterioration of the driving means and the holding member over time, and it is possible to reduce the energy consumption in the driving means and reduce the image. It is possible to provide a contact / separation member contact / separation device that can prevent image disturbance on the carrier and contribute to good image formation.

  If the engagement / disengagement means has an urging means for urging the direction in which the locked state is released with a force large enough to maintain the locked state in the locked state, By reducing the load on the engagement / disengagement means, it is possible to suppress the deterioration of the engagement / disengagement means over time, and the energy consumed in the engagement / disengagement means can also be reduced by the urging force of the urging means, with more certainty. Provided is a contact / separation member contact / separation device that can separate the contact / separation member from the image carrier and can prevent disturbance of the image on the image carrier to a higher degree and contribute to good image formation with high accuracy. can do.

  The contact / separation member supporting means for supporting the contact / separation member so that the weight of the contact / separation member works in a direction in which the engagement state is released by a force large enough to maintain the engagement state in the engagement state. By so doing, it is possible to suppress the deterioration over time of the engaging / disengaging means by reducing the load on the engaging / disengaging means by the pressurizing means, and the energy of the engaging / disengaging means is locked by the weight of the contacting / separating member. Can be reduced by acting in the direction to release the image, and the contact / separation member can be separated from the image carrier with more certainty, and the disturbance of the image on the image carrier can be prevented to a higher degree. Thus, it is possible to provide a contact / separation member contact / separation apparatus that can contribute to good image formation with high accuracy.

  When the locking state is formed by the engaging / disengaging means, the pressurizing means urges the locking member to maintain this state, and the locking state is released by the engaging / disengaging means. In some cases, if the locking member is biased so as to maintain this state, these states can be stably obtained, and the load on the engaging / disengaging means by the pressurizing means can be reduced more reliably. As a result, it is possible to suppress the deterioration of the engaging / disengaging means over time, and it is possible to reduce the energy consumption of the engaging / disengaging means, and it is possible to maintain the locked state with more certainty. It is possible to provide a contact / separation member contact / separation device that can prevent image disturbance to a higher degree and can contribute to good image formation with high accuracy.

  If the contact / separation member is a transfer member for transferring an image on the image carrier, the load on the engagement / disengagement means by the pressurizing means can be reduced while securing the transfer performance by the transfer member. A transfer member that can suppress deterioration with time of the engagement / disengagement means, can reduce energy consumption in the engagement / disengagement means, can prevent image disturbance on the image carrier, and can contribute to good image formation. The contacting / separating member contacting / separating device applied to the above can be provided.

  If the jam is detected by the jam detecting means for detecting the occurrence of the jam and / or when the image for image adjustment is carried on the image carrier, the transfer member is released. It is possible to suppress deterioration over time of the engagement / disengagement means by reducing the load on the engagement / disengagement means by the pressurizing means, including when performing jam processing between the image carrier and the image carrier, etc. In addition, energy consumption in the engagement / disengagement means can be reduced, and disturbance of the image on the image carrier can be prevented even during such image adjustment, contributing to higher-quality image formation. A contact / separation member contact / separation apparatus can be provided.

  The present invention resides in an image forming apparatus having such a contact / separation member contact / separation device and an image carrier to which the contact / separation member contacts / separates, and therefore, it is possible to reduce the load on the engagement / disengagement unit by the pressurization unit. Provided is an image forming apparatus capable of suppressing deterioration of the detaching means with time, reducing energy consumption in the engaging / disengaging means and preventing disturbance of the image on the image carrier, and capable of forming a good image. can do.

  FIG. 1 shows an outline of an image forming apparatus to which the present invention is applied. The image forming apparatus 100 is a multifunction peripheral of a copying machine, a printer, and a facsimile machine, and can perform full-color image formation, but other image forming apparatuses, that is, a monochrome machine, a copying machine, and a printer. It may be a single facsimile, or another multi-function machine such as a copier / printer multi-function machine. When used as a printer, the image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. This is the same when the image forming apparatus 100 is used as a facsimile.

  The image forming apparatus 100 can form an image on a sheet-like recording medium using not only plain paper generally used for copying, but also OHP sheets, cardboard, cardboard, cardboard, and envelopes. It is. The image forming apparatus 100 is also a double-sided image forming apparatus capable of forming images on both sides of a transfer sheet that is a recording medium as a recording medium.

  The image forming apparatus 100 is a photoconductor that is a latent image carrier as a first image carrier that can form an image as an image corresponding to each color separated into yellow, magenta, cyan, and black. A tandem structure in which the photosensitive drums 20Y, 20M, 20C, and 20BK are arranged in parallel, in other words, a tandem system is adopted.

  Photosensitive drums 20Y, 20M, 20C, and 20BK that are surface moving members are rotatably supported by a frame (not shown) of a main body 99 that functions as a printer unit of the image forming apparatus 100, and an intermediate transfer member as a second image carrier. These are arranged in this order from the upstream side in the A1 direction, which is the moving direction of the transfer belt 11 serving as an intermediate transfer belt as a transfer body, which is the counterclockwise direction in FIG. Y, M, C, and BK added after the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black.

  Each of the photosensitive drums 20Y, 20M, 20C, and 20BK has image forming units 60Y, 60M, 60C, and 60BK for forming yellow (Y), magenta (M), cyan (C), and black (BK) images, respectively. Is provided.

  The photoconductive drums 20Y, 20M, 20C, and 20BK are positioned on the outer peripheral surface side of the transfer belt 11 that is configured as an endless belt disposed substantially at the center inside the main body 99, that is, on the image forming surface side.

  The transfer belt 11 is movable in the direction of the arrow A1 while facing the photosensitive drums 20Y, 20M, 20C, and 20BK. Visible images, that is, toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are respectively superimposed and transferred onto a transfer belt 11 as a transfer medium that moves in the direction of the arrow A1, and then collectively onto the transfer paper S. It is designed to be transcribed. Therefore, the image forming apparatus 100 is an intermediate transfer type image forming apparatus.

  The lower portion of the transfer belt 11 faces each of the photosensitive drums 20Y, 20M, 20C, and 20BK. The facing position, which is the opposed portion, is on the respective photosensitive drums 20Y, 20M, 20C, and 20BK. A primary transfer portion 58 is formed as a primary transfer region for transferring the toner image to the transfer belt 11.

  In the superimposing transfer to the transfer belt 11, the toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. As described above, voltage application is performed by primary transfer rollers 12Y, 12M, 12C, and 12BK as first transfer rollers disposed at positions facing the respective photosensitive drums 20Y, 20M, 20C, and 20BK across the transfer belt 11. Thus, the timing is shifted from the upstream side toward the downstream side in the A1 direction.

  The transfer belt 11 has a multilayer structure in which the base layer is made of a material with little elongation, the surface of the base layer is covered with a smooth material, and the coat layer is formed on the base layer. Examples of the material of the base layer include a fluororesin, a PVDF sheet, and a polyimide resin. Examples of the material of the coating layer constituting the surface include a fluorine resin having good smoothness.

  Although not shown, the transfer belt 11 has a detent guide as a detent member at each edge. The offset guide is provided to prevent the transfer belt 11 from being biased in any direction perpendicular to the paper surface in FIG. 1 when the transfer belt 11 rotates in the A1 direction. The stopper guide is made of urethane rubber, but can be made of various rubber materials such as silicon rubber.

  In the main body 99, the image forming apparatus 100 is opposed to image forming units 60Y, 60M, 60C, and 60BK that are image forming stations serving as four image forming apparatuses, and above the photosensitive drums 20Y, 20M, 20C, and 20BK. The transfer belt unit 10 is an intermediate transfer unit serving as a transfer unit including the transfer belt 11, and the secondary transfer is provided on the right side of the transfer belt 11 in FIG. An optical scanning device 8 as an exposure device as a writing device as an optical unit which is an optical writing unit as a latent image forming means disposed opposite to the apparatus 5 and below the image forming units 60Y, 60M, 60C and 60BK. And have.

  The image forming apparatus 100 can also stack a large number of transfer sheets S transported toward the secondary transfer portion 57 as a secondary transfer area between the transfer belt 11 and the secondary transfer apparatus 5 in the main body 99. A sheet feeding device 61 that is a sheet feeding tray as a simple sheet feeding unit, and a recording sheet S conveyed from the sheet feeding device 61 at a toner image formation timing by the image forming units 60Y, 60M, 60C, and 60BK. It has a registration roller pair 4 that feeds toward the secondary transfer portion 57 at a predetermined timing, and a sensor (not shown) that detects that the leading edge of the transfer paper S has reached the registration roller pair 4.

  The image forming apparatus 100 also includes a fixing device 6 serving as a fixing unit of a roller fixing system for fixing the toner image on the transfer sheet S on which the toner image is transferred in the main body 99, and a forward rotation. Disposed above the transfer belt unit 10 are a discharge roller 7 that rotates forward and backward as a discharge roller pair that is a discharge roller that discharges the fixed transfer paper S to the outside of the main body 99, yellow, cyan, Paper discharge for stacking toner bottles 9Y, 9M, 9C, 9BK filled with magenta and black toners, and transfer paper S disposed on the upper side of the main body 99 and discharged to the outside of the main body 99 by the discharge roller 7. And a tray 17.

  The image forming apparatus 100 also has an opening / closing part 51 that opens and closes the secondary transfer apparatus 5 with respect to the main body 99, and a part of the opening / closing part 51 passes through the opening / closing part 51. The reverse conveyance path 21 reverses and conveys toward the registration roller pair 4 while bypassing the fixing device 6 during the reverse rotation of the sheet 7, and the transfer sheet S to the reverse conveyance path 21 when the sheet discharge roller 7 rotates in the reverse direction. It has a switching claw 22 for guiding, and a transport roller 23 that is disposed in the reverse transport path 21 and transports the transfer paper S toward the registration roller pair 4.

  The image forming apparatus 100 also includes, in the main body 99, a driving device (not shown) that rotationally drives the photosensitive drums 20Y, 20M, 20C, and 20BK, a CPU (not shown) that controls the overall operation of the image forming device 100, a memory, and the like. Including control means (not shown).

  The image forming apparatus 100 also has a reading device 98 as a scanner that is positioned above the main body 99 and reads an original, and a front surface as an unshown openable face plate that opens to the near side in FIG. 1 when the inside of the main body 99 is opened. And a panel.

The image forming apparatus 100 is also provided with a start switch (not shown) for instructing image formation start, and the operation of the image forming apparatus 100 can be designated, and as a display unit for performing a predetermined display For example, the image forming apparatus 100 has an operation panel (not shown) that can display that when a problem occurs in the image forming apparatus 100.
The image forming apparatus 100 is an in-body discharge type image forming apparatus in which the discharge tray 17 is located above the main body 99 and below the reading device 98.

  In addition to the transfer belt 11, the transfer belt unit 10 includes primary transfer rollers 12Y, 12M, 12C, and 12BK as primary transfer bias rollers, and a drive roller 72 that is a drive member around which the transfer belt 11 is wound. The cleaning counter roller 74 as a tension roller, the tension roller 33 as a support roller for tensioning the transfer belt 11 together with the driving roller 72 and the cleaning counter roller 74, and the transfer belt 11 from the inside of the transfer belt 11 A tension roller 75 for applying a predetermined tension to the transfer belt 11 is provided along with the cleaning counter roller 74.

  The transfer belt unit 10 is also provided with a cleaning device 13 as a belt cleaning device, which is an intermediate transfer member cleaning device that is disposed facing the transfer belt 11 at a position facing the cleaning counter roller 74 and cleans the surface of the transfer belt 11. A drive system (not shown) that rotationally drives the drive roller 72, and a power supply and bias control means (not shown) that apply a primary transfer bias to the primary transfer rollers 12Y, 12M, 12C, and 12BK are provided. .

  The cleaning facing roller 74, the stretching roller 33, and the tension roller 75 are driven rollers that rotate along with the transfer belt 11 that is rotationally driven by the driving roller 72. The primary transfer rollers 12Y, 12M, 12C, and 12BK press the transfer belt 11 from the back surface thereof toward the photosensitive drums 20Y, 20M, 20C, and 20BK to form primary transfer nips. The primary transfer nip is formed in a portion of the transfer belt 11 that extends between the tension roller 75 and the stretching roller 33. The tension roller 33 and the tension roller 75 have a function of stabilizing the primary transfer nip.

  In each primary transfer nip, a primary transfer electric field is formed between the photosensitive drums 20Y, 20M, 20C, and 20BK and the primary transfer rollers 12Y, 12M, 12C, and 12BK due to the influence of the primary transfer bias. . The toner images of the respective colors formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are primarily transferred onto the transfer belt 11 due to the influence of the primary transfer electric field and nip pressure.

The driving roller 72 is in contact with the secondary transfer device 5 via the transfer belt 11 to form a secondary transfer portion 57.
The cleaning facing roller 74 has a function as a tension roller as a pressure member that applies a predetermined tension suitable for transfer to the transfer belt 11 together with the tension roller 75.

  The cleaning device 13 is disposed on the left side of the transfer belt unit 10 in FIG. 1, specifically, on the left side of the cleaning counter roller 74. The cleaning device 13 includes a cleaning blade 76 as a cleaning member disposed so as to contact the transfer belt 11 at a position facing the cleaning counter roller 74, a case 77 containing the cleaning blade 76 therein, and FIG. And a waste toner collecting bottle (not shown) disposed on the front side of the case 77 in the drawing.

  The cleaning device 13 cleans the transfer belt 11 by scraping and removing foreign matters such as residual toner on the transfer belt 11 with a cleaning blade 76. Such foreign matter removed from the transfer belt 11 is stored in a waste toner recovery bottle. The waste toner collection bottle can be taken out to the front side of the paper in FIG. 1 with the front panel opened, and can be replaced with a new one when the foreign matter inside becomes full. Note that cleaning devices 71Y, 71M, 71C, and 71BK, which will be described later, similarly have replaceable waste toner collection bottles.

  The sheet feeding device 61 accommodates a plurality of transfer sheets S in a state of a stack of transfer sheets, and is disposed below the optical scanning device 8 below the main body 99. The sheet feeding device 61 is loaded with a paper bank 26 in which a plurality of sheet feeding cassettes 25 capable of accommodating a plurality of transfer sheets S in a bundle of sheets are arranged in a stack in the vertical direction, and each sheet feeding cassette 25. Of the transfer sheet S, the feeding roller 24 as a sheet feeding roller contacting the upper surface of the uppermost transfer sheet S and only one of the transfer sheets S fed by the sheet feeding roller 24 are separated and further conveyed. (Not shown) and the feed roller 24 is rotated counterclockwise at a predetermined timing to feed the uppermost transfer sheet S toward the registration roller pair 4. It is like that.

  In the sheet feeding device 23, the feeding roller 24 is selectively driven to rotate counterclockwise in the figure, and the separation roller acts so that the uppermost of the transfer sheets S stacked in the sheet feeding cassette 25 is actuated. The transfer sheet S is fed toward the registration roller pair 4, and the transferred transfer sheet S is abutted and stopped while being sandwiched between the rollers of the registration roller pair 4.

  The secondary transfer device 5 is disposed to face the drive roller 72. The secondary transfer device 5 has a secondary transfer roller 66 as a secondary transfer roller, which is a transfer member disposed so as to sandwich the transfer belt 11 with the drive roller 72.

  The secondary transfer device 5 also has a sheet conveying function for conveying the transfer paper S after the toner image is transferred to the fixing device 6. The secondary transfer device 5 is disposed in the opening / closing part 51. The remainder of the secondary transfer device 5 will be described later.

  The opening / closing part 51 includes a part of the reverse conveying path 21, a shaft 52 serving as a rotation center when rotating with respect to the main body 99, and a manual feed disposed on the outer surface side in addition to the secondary transfer device 5. The paper feeding device 53 and a jam detecting sensor 54 as jam detecting means for detecting the occurrence of jam caused by the jam of the transfer paper S in the secondary transfer portion 57, and the secondary transfer device 5 and Along with the manual paper feeder 53, the main body 99 can be opened and closed.

  As shown in FIG. 2, when the opening / closing portion 51 is opened with respect to the main body 99, the secondary transfer portion 57 is opened, and the transfer belt unit 10 is detachable from the main body 99 as shown in FIG. Thus, maintenance of the transfer belt 10 and the main body 99 is facilitated. The opening / closing unit 51 includes the reverse conveyance path 21 at a relatively large ratio, and functions as a double-sided door constituting a part of the double-sided unit constituted by the reverse conveyance path 21 and the switching claw 22.

  The jam detection sensor 54 is a photo sensor as an optical sensor, and can detect the transfer sheet S, and the detection signal is input to the control means. The control means determines whether or not a jam has occurred based on the signal. When the control means determines that a jam has occurred, the control means displays the fact on the liquid crystal display device and alerts the user or the like. The jam detection sensor 54 also functions as an opening detection unit that detects whether or not the opening / closing unit 51 is opened with respect to the main body 99, and when the detection signal is input to the control unit, the control unit controls the opening / closing unit 51. Judge whether there is open.

  The manual sheet feeding device 53 can be opened and closed with respect to the opening / closing unit 51, and the manual feeding tray 27 as a manual sheet feeding tray on which the transfer sheets S can be stacked while being opened with respect to the opening / closing unit 51, A feeding roller 28 as a paper feeding roller that contacts the upper surface of the uppermost transfer paper among the transferred transfer paper S, a separation roller 29 that separates the transfer paper fed by the feeding roller 28 one by one, and manual feed The shaft 19 supports the tray 27 so as to be openable and closable with respect to the opening / closing portion 51, and a paper sensor (not shown) that detects that the transfer paper is placed on the manual feed tray 34.

  In the manual sheet feeding device 53, the feeding roller 28 is driven to rotate in the clockwise direction in the drawing, and the separation roller 29 acts to feed the uppermost transfer sheet S toward the registration roller pair 4 for conveyance. The transferred transfer sheet S is abutted and stopped while being sandwiched between the rollers of the registration roller pair 4.

  The fixing device 6 includes a heating roller 62 having a heat source (not shown) therein, a fixing belt 64 wound around the heating roller 62, a fixing roller 65 wound around the fixing belt 64 together with the heating roller 62, a fixing roller 65, And a pressure roller 63 that presses against the fixing belt 64 to form a fixing nip as a fixing portion that is a pressing portion. The heating roller 62, the fixing belt 64, and the fixing roller 65 constitute a belt unit in which the fixing belt 64 moves endlessly. The fixing device 6 fixes the carried toner image on the surface of the transfer paper S by the action of heat and pressure by passing the transfer paper S carrying the toner image in a manner sandwiching the fixing nip. .

  The yellow, cyan, magenta, and black toners in the toner bottles 9Y, 9M, 9C, and 9BK are polymerized toners that are rotated by driving means (not shown) to discharge the toner, and are not shown by a pipe (not shown). A predetermined replenishment amount is supplied to the developing devices 80Y, 80M, 80C, and 80BK provided in the image forming units 60Y, 60M, 60C, and 60BK, as will be described later, through the configured conveyance path.

  Although not shown in detail, the reading device 98 includes a contact glass for placing an original, a light source for irradiating light on the original placed on the contact glass, and a first light that reflects light reflected on the original from the light source. A first traveling body that travels in the left-right direction in FIG. 1, a second traveling body that includes a second reflector that reflects light reflected by the reflector of the first traveling body, and a second traveling body. An image forming lens for forming an image of light from the body, a reading sensor for receiving the light passing through the image forming lens and reading the contents of the document are provided.

  The image forming units 60Y, 60M, 60C, and 60BK have the same configuration. The image forming units 60Y, 60M, 60C, and 60BK are primary transfer rollers as process means around the photosensitive drums 20Y, 20M, 20C, and 20BK along the rotation direction B1 that is clockwise in FIG. 12Y, 12M, 12C, 12BK, cleaning devices 71Y, 71M, 71C, 71BK as cleaning means, static elimination devices 78Y, 78M, 78C, 78BK as static elimination means, and charging device 79Y as a charging means for performing AC charging 79M, 79C, 79BK, and developing devices 80Y, 80M, 80C, 80BK as developing means for performing development with a two-component developer.

  The photosensitive drum 20Y, the cleaning device 71Y, the charge removal device 78Y, the charging device 79Y, and the developing device 80Y are integrated to form a process cartridge. The components around the photoconductive drums 20M, 20C, and 20BK are similarly integrated to form a process cartridge. These process cartridges are detachable in the direction of the rotation axis of the photosensitive drums 20Y, 20M, 20C, and 20BK on the front side in FIG. 1 with the front panel opened. Making a process cartridge in this way is very preferable because it can be handled as a replacement part, so that the maintainability is remarkably improved.

  In the image forming apparatus 100 having such a configuration, image formation is performed by performing the following image forming processes in the image forming units 60Y, 60M, 60C, and 60BK, respectively, by pressing a start switch or the like. That is, when a signal indicating that a color image is to be formed is input, data corresponding to the image to be formed is acquired by reading the document in the reading device 98 as appropriate, and the driving roller 72 is Driven, the transfer belt 11, the cleaning facing roller 74, the stretching roller 33, and the tension roller 75 are driven to rotate, and the photosensitive drums 20Y, 20M, 20C, and 20BK are rotationally driven in the B1 direction.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are uniformly charged on the surface by the charging devices 79Y, 79M, 79C, and 79BK as the B1 rotates, and the laser beam exposure scanning from the optical scanning device 8 is performed. To form an electrostatic latent image corresponding to each color of yellow, magenta, cyan, and black, and the electrostatic latent image is developed with toners of yellow, magenta, cyan, and black by developing devices 80Y, 80M, 80C, and 80BK. As a result, the image is visualized to form a single color image composed of toner images of magenta, cyan, and black.

  The yellow, magenta, cyan, and black toner images obtained by development are sequentially superimposed on the same position on the transfer belt 11 rotating in the A1 direction by the primary transfer rollers 12Y, 12M, 12C, and 12BK. As a result, a composite color image is formed on the transfer belt 11.

  On the other hand, with the input of a signal indicating that a color image should be formed, one of the paper feed roller 24 corresponding to each paper feed cassette 25 and the paper feed roller 28 corresponding to the manual feed tray 27 is selected and rotated. The transfer sheet S is fed out and separated and conveyed one by one, and the conveyed transfer sheet S stops in a state where it abuts against the registration roller pair 4. In the case of double-sided image formation, the transfer sheet S on which an image is fixed on one side of the fixing device 6 as described later is abutted against the registration roller pair 4 while being reversed through the reverse conveyance path 21. Stop in the state.

  The registration roller pair 4 rotates in accordance with the timing at which the composite color image superimposed on the transfer belt 11 moves to the secondary transfer unit 57 as the transfer belt 11 rotates in the A1 direction. The composite color image is in close contact with the transfer sheet S sent to the secondary transfer unit 57, and is secondarily transferred and recorded on the transfer sheet S by the action of the nip pressure.

  The transfer sheet S is transported in the E1 direction by the secondary transfer device 5 and the transfer belt 11 rotating in the A1 direction, and sent to the fixing device 6. In the fixing device 6, the fixing unit between the heating roller 62 and the pressure roller 63 is sent. When the toner passes through the toner, the carried toner image, that is, the synthesized color image is fixed by the action of heat and pressure.

  The transfer sheet S on which the composite color image has been fixed, which has passed through the fixing device 6, is discharged out of the main body 99 through the discharge roller 7 and stacked on the discharge tray 17 at the top of the main body 99. In the case of double-sided image formation, the transfer sheet S that has been fixed on one side is conveyed again through the reverse conveyance path 21 toward the registration roller pair 4.

  In the photosensitive drums 20Y, 20M, 20C, and 20BK, the transfer residual toner remaining after the transfer is removed by the cleaning devices 71Y, 71M, 71C, and 71BK, the charges are discharged by the charge removing devices 78Y, 78M, 78C, and 78BK, and the charging devices 79Y, It is subjected to the next charging by 79M, 79C, 79BK.

  The surface of the transfer belt 11 that has passed the secondary transfer portion 57 after the secondary transfer is cleaned by a cleaning blade 76 provided in the cleaning device 13 to prepare for the next transfer.

  Such an image forming operation is performed every predetermined number of times of image formation, for example, so-called process control as well as an image forming instruction by a user based on an input operation by an operation panel or the like. Also, it is performed at the time of image adjustment so that image formation is performed satisfactorily. Such image adjustment is performed for adjusting the density and color tone of toner constituting the image.

  As shown in FIGS. 4 and 5, the secondary transfer device 5 includes a secondary transfer roller 66 that can contact and separate from the transfer belt 11. Here, the secondary transfer roller 66 functions as a contact / separation member that contacts and separates from the transfer belt 11. The secondary transfer device 5 includes a contact / separation member contact / separation device 97 for causing the secondary transfer roller 66 to function as the contact / separation member.

  The contact / separation member contact / separation device 97 includes a spring 81 serving as a pressurizing source serving as a pressurizing unit serving as a pressing unit that presses the secondary transfer roller 66 toward the driving roller 72, and a secondary transfer. A guide member 82 serving as a main body rail that guides the roller 66 in the direction of contact with and away from the driving roller 72 and the secondary transfer roller 66 are supported from below, and the secondary transfer roller 66 is brought into contact with and separated from the transfer belt 11 by swinging. A pressure lever 83 as a support member, a cam 84 for moving the secondary transfer roller 66 to and away from the drive roller 72, a motor 85 as a drive means for rotating the cam 84, and the pressure lever 83 are swung. A shaft 86 that is freely supported, a stage 87 as a support base that supports the spring 81 from below, and a rotation center shaft that is constituted by a part of a core metal (not shown) of the secondary transfer roller 66 is disposed. And a rolling bearing 88.

  Here, if the biasing force of the spring 81 is always input to the cam 84 and the motor 85 via the cam 84, they can easily deteriorate over time. Further, when the urging force of the spring 81 is input from the cam 84 side to the motor 85 as a rotational load, the motor 85 may be further deteriorated, and the phase of the cam 84 is resisted against the rotational load. When it is necessary to maintain the power supply to the motor 85 in order to maintain the power consumption, the energy consumption can be increased.

  Therefore, the contact / separation member contact / separation device 97 locks the pressure lever 83 and maintains the posture of the pressure lever 83 in a state where the secondary transfer roller 66 is in contact with the transfer belt 11, thereby the secondary transfer roller 66. 4 is in contact with the transfer belt 11 and maintains the locking state shown in FIG. 4, and a stopper 89 as a locking member to which one end of the spring 81 is connected, and forms such a locking state or the locking state. 5 and the engagement / disengagement means 90 for forming the release state shown in FIG. 5. When the engagement state is released and the release state is formed by the engagement / disengagement means 90, the transfer belt 11 by the spring 81 is formed. When the secondary transfer roller 66 is disengaged from the transfer belt 11 and the secondary transfer roller 66 is separated from the transfer belt 11 while the engagement state is formed by the engagement / disengagement means 90, the cam 84 and the motor 85 from the spring 81 are formed. Input to stop, Cam 84 of the urging force of Nawachibane 81, transmitted to the motor 85 is cut off, the input to the disengagement means 90 from the spring 81 is adapted to stop.

  The engaging / disengaging means 90 includes a lever 91 as a connecting member that is swingably connected to the pressure lever 83 and the stopper 89, a spring 92 as an urging means, a cam 84, and a motor 85. .

  One end of the spring 81 is connected to the stopper 89, and the other end is fixed to a stationary member 93 on the main body side of the secondary transfer device 5. The immovable member 93 is displaced with respect to the main body 99 when the opening / closing part 51 opens and closes with respect to the main body 99. The spring 81 presses the secondary transfer roller 66 against the transfer belt 11 via the stopper 89 and the pressure lever 83 in the locked state.

The guide member 82, the motor 85, the shaft 86, and the stage 87 are fixed to the immovable member 93.
The guide member 82 supports the rolling bearing 88 so as to be slidable and slidable in a direction inclined with respect to the horizontal direction. The guide member 82 extends in such a direction so that the weight of the secondary transfer roller 66 acts in a direction in which the locked state is released by a force large enough to maintain the locked state in the locked state. It functions as a contacting / separating member supporting unit that supports the secondary transfer roller 66. The guide member 82 may be a groove formed in the immobile member 93.

  The pressure lever 83 has a U-shape, and a bent portion, which is a midway portion, is rotatably supported by a shaft 86. The pressure lever 83 supports the secondary transfer roller 66 from below at one end thereof via a rolling bearing 88 supported by the guide member 82. The pressure lever 83 has a cylindrical shaft portion 83 a that is rotatably connected to the lever 91 at the tip of the other end. The pressure lever 83 faces the stopper 89 at the shaft portion 83a and smoothly engages.

  The cam 84 has an elliptical shape, and is disposed at a biased position on the major axis and has a shaft 84a that forms the center of rotation. The cam 91 is positioned on the major axis and is in the locked state as shown in FIG. And a small-diameter portion that is located on the opposite side of the large-diameter portion and that contacts the lever 91 in the released state as shown in FIG.

  The motor 85 supports the cam 84 on the shaft 84a. The motor 85 is a stepping motor, the drive of which is controlled by the control means, and the phase of the cam 84 is set to either the state shown in FIG. 4 or the state shown in FIG. Since the cam 84 engages with the lever 91 at the large diameter portion in the locked state and contacts the lever 91 at the small diameter portion in the released state, the shaft 84a from the springs 81 and 91 is rotated by the motor 85 in any state. The input of the direction to be stopped is stopped, that is, the rotational force by the shaft 84a is deactivated. Therefore, in any state, it is not necessary to supply power to the motor 85 to maintain the state, power is saved, and rotational stress is not generated by the shaft 84a, and deterioration thereof is suppressed.

  The shaft 86 has a length from the support position of the pressure lever 83 to the contact position of the pressure lever 83 with respect to the secondary transfer roller 66, and from the support position to the contact position of the pressure lever 83 with respect to the stopper 89. The pressure lever 83 is supported at a position where the length of the pressure lever 83 is longer, and the rotation fulcrum of the pressure lever 83 is configured. As a result, even if the urging force of the spring 81 is small, the spring will be described later. It is possible to maintain a locked state, a released state, etc. by 81.

  The stage 87 supports the spring 81 from the stationary member 93 side to the middle part in the extending direction of the spring 81. As shown in FIG. 4, the spring 81 is mostly supported by the stage 87 in the locked state and is substantially linear, but as shown in FIG. 5, the portion supported by the stage 87 in the released state. Decreases, and the stopper 89 side is bent downward.

  Since the rolling bearing 88 is provided, resistance to the guide member 82 and the pressure lever 83 is reduced, and the secondary transfer roller 66 is smoothly brought into and out of contact with the transfer belt 11.

  The stopper 89 engages and abuts the shaft portion 83a in the locked state, and engages and abuts the first engaging surface 89a facing the substantially vertical direction in the same state and the shaft portion 83a in the released state. The second engagement surface 89b inclined with respect to the engagement surface 89a is connected to the pressure lever 91 and is long in a direction substantially parallel to the direction in which the biasing force is applied to the stopper 89 by the spring 81 in the locked state. And a long hole 89c as a guide. The long hole 89c may be a groove.

  The lever 91 is rotatably supported by the shaft 83a at one end thereof, is rotatable relative to the pressure lever 83, and is connected to one end of the spring 92 at the other end. The lever 91 has a pin 91a slidably fitted in the long hole 89c in the middle. Therefore, the lever 91 is swingably connected to the pressure lever 83 and the stopper 89, and the lever 91, the pressure lever 83, and the stopper 89 constitute a link mechanism. The lever 91 is supported from below by a cam 84 between the pin 91a and the other end. The pin 91a is positioned in the middle of the long hole 89c in the locked state, and is in contact with the end of the long hole 89c opposite to the first engagement surface 89a in the released state.

  One end of the spring 92 is connected to the other end of the lever 91, and the other end is fixed to the immovable member 93. The spring 92 urges the lever 91 in a direction in which the locked state is released and a direction in which the lever 91 abuts against the cam 84 with a force large enough to maintain the locked state in the locked state.

  With such a configuration, in the engagement / disengagement means 90, the cam 84 rotates by driving the motor 85 based on the control by the control means, and the large diameter of the cam 84 resists the biasing force of the spring 92 as shown in FIG. When the portion comes into contact with the lever 91, the shaft portion 83a comes into contact with the first engagement surface 89a, the secondary transfer roller 66 is pushed up by the pressure lever 83, and is brought into pressure contact with the transfer belt 11 to form a locked state. The shaft 83a is maintained in contact with the first engagement surface 89a by the biasing force of the spring 81, and the locked state is maintained. In this respect, the control means functions as an engagement / disengagement control means, particularly as a locking control means.

  When the motor 85 is driven based on control by the control means, the cam 84 rotates against the biasing force of the spring 81 and the small diameter portion of the cam 84 contacts the lever 91 as shown in FIG. The portion 83a climbs over the corner of the stopper 89 located at the boundary between the first engagement surface 89a and the second engagement surface 89b, rides on the second engagement surface 89b, and then enters the second engagement surface 89b. The pressure lever 83 rotates in the clockwise direction in the figure, and the secondary transfer roller 66 is displaced downward by its own weight while being supported by the pressure lever 83 from below, and is separated from the transfer belt 11 and separated. The shaft portion 83a is ridden on the second engagement surface 89b by the urging force of the spring 81, and the locked state is maintained. In this respect, the control means functions as an engagement / disengagement control means, particularly as a separation control means. It should be noted that the corner between the first engagement surface 89a and the second engagement surface 89b is formed on the first engagement surface 89a and the second engagement surface 89b of the shaft portion 83a. It is possible to form a curved surface so that the movement between the two can be performed smoothly. However, these states are prevented from being released when the locked state and the released state should be maintained.

  In this way, when the engagement state is formed by the engagement / disengagement means 90, the spring 81 biases the stopper 89 so as to maintain the engagement state, and the engagement state is released and the engagement state is released. When the release state is established through a transition state between the state and the release state, the spring 81 biases the stopper 89 so as to maintain this state. In the locked state, the input to the engagement / disengagement means 90 from the spring 81 is stopped and the pressure is released, and naturally the input to the motor 85 in the direction to rotate the shaft 84a from the spring 81 is also stopped, In the state and the released state, the input to the engagement / disengagement means 90 from the spring 81 is performed on the second engagement surface 89b, so that the pressure is not released, but the shaft 84a from the spring 81 to the motor 85 is rotated. The direction input is stopped. Therefore, torque by the motor 85, in other words, power supply to the motor 85 is required only when the locked state and the released state are released and the state is shifted to the other state, and the deterioration of the motor 85 and the power consumption are suppressed. .

  Since this is provided, the spring 92 generates a biasing force that cancels the biasing force of the spring 81 when the locked state is released and the transition to the transient state or the released state occurs. The advantage is that it becomes easier. However, the spring 92 can be omitted when the lever 91 can be released from the locked state by its own weight and can be shifted to the transient state or the released state.

  Since the stage 87 is provided with this, the release state is released, and when the transition to the transient state or the locking state is performed, a biasing force in a direction to cancel the bent state of the spring 81 is generated, and the transition is performed. The advantage is that it is more likely to occur. The magnitude of the biasing force in the direction to cancel the bent state of the spring 81 is a size that maintains the released state. However, the stage 87 can be omitted.

  The cam 84 engages with the lever 91 in the locked state, the transient state, and the released state, and functions as a holding member that holds the posture of the lever 91 so as to maintain these states. However, in a configuration in which the spring 92 is omitted, the lever 91 can be separated from the cam 84 in the transient state and the released state. Therefore, the cam 84 as the holding member is engaged with the lever 91 at least in the locked state and locked. The posture of the lever 91 is maintained so as to maintain the state. In this regard, as already described, when the cam 84 is in the locked state and abuts against the lever 91 at the large diameter portion and in the released state and abuts against the lever 91 at the small diameter portion, the motor 85 has a spring in any state. The input of the direction to rotate the shaft 84a from 81 is stopped, the motor 85 does not need to be supplied with power to maintain the state, power is saved, and no rotational stress is generated by the shaft 84a. However, considering that the lever 91 can be separated from the cam 84 in the transient state and the released state in the engagement / disengagement means 90, the engagement / disengagement means 90 is at least In the state where the locked state is formed, the input to the motor 85 in the direction to rotate the shaft 84a from the spring 81 is stopped. Since the cam 84 can be switched between the locked state and the released state if it rotates once at the maximum, the number of rotations of the motor 85 can be suppressed to extend the life and reduce the power consumption. ing.

  In the released state, the structure of the contact / separation member contact / separation device 97 is such that the pressure lever 83 is also separated from the stopper 89, so that the pressure release state can be established. Considering this, the stop of the input to the engaging / disengaging means 90 from the spring 81, that is, the depressurized state occurs at least in the locked state.

  In the image forming apparatus 100, the secondary transfer roller 66 is separated from the transfer belt 11 by releasing the locked state and switching to the released state, based on an image formation instruction by the user or for image adjustment. When the color image is formed and until the toner image of all colors is carried on the transfer belt 11, and when the toner image of all colors is carried on the transfer belt 11, the release state is set. The secondary transfer roller 66 is brought into contact with the transfer belt 11 by releasing and switching to the locked state, so that the secondary transfer onto the transfer paper S can be performed.

  In the image forming apparatus 100, when the control unit determines that a jam has occurred, the secondary transfer roller 66 is separated from the transfer belt 11 by releasing the locked state and switching to the released state. . When the control means determines that the jam has occurred, the user is notified of the jam by the liquid crystal display device, and the opening / closing part 51 is opened with respect to the main body 99 as shown in FIG. However, when the opening / closing part 51 is opened with respect to the main body 99, in order to prevent problems such as applying unnecessary stress to the transfer belt 11, the secondary transfer roller 66 and the like to deteriorate them. When the control means determines that a jam has occurred, the locking state is released and the release state is switched. Further, when the control means determines that the jam has been resolved, the release state is released and switching to the locked state is performed. However, this switching is performed under the condition that the control means determines that the opening / closing part 51 is closed. This is because if the opening / closing part 51 is closed in the locked state, a problem may occur in that unnecessary stress is applied to the transfer belt 11, the secondary transfer roller 66, and the like to deteriorate them.

  The components of the contact / separation member contacting / separating device 97 are disposed on the main body 99 side within a range in which the locked state is maintained when the opening / closing portion 51 is opened. May be separated from the contact / separation member contact / separation device 97.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the driving means provided in the engaging / disengaging means for forming or releasing the locked state may be a solenoid instead of a motor. In this case, the driving means also serves as a holding member that holds the posture of the connecting member so as to engage with the connecting member at least in the locked state and maintain the locked state.

  In the locked state, the position holding member that holds the position of the locking member in the locked state is set in the locked state, for example, when the position of the locking member becomes unstable due to the force of the pressure means alone. You may arrange | position in the contact / separation member contact-and-separation apparatus in the aspect which does not prevent cancelling | releasing and shifting to a cancellation | release state further. The position holding member may hold the position of the locking member even in the released state, and may be configured not to prevent such a transition even in a transition state between them. In this respect, the position holding member holds the position of the locking member at least in the locked state.

  The transfer member may be a belt instead of a roller. The contact / separation member is not limited to the transfer member as long as it is a member that needs to contact / separate the image carrier, and may be a cleaning member such as the cleaning blade 76. The cleaning member may be a rotating body having a roller shape instead of a blade shape. However, the contacting / separating member is not limited to the rotating body.

  The present invention is not a so-called tandem-type image forming apparatus such as the image forming apparatus 100, and each color toner image is formed by sequentially forming a toner image of each color on an image carrier such as a single photosensitive drum or a photosensitive belt. The same application can be applied to a so-called one-drum type image forming apparatus that obtains a color image by superimposing sequentially, and can be a contact / separation member contact / separation device for the contact member of the image carrier, such as a transfer member or a cleaning member. In addition, if necessary, the present invention may be applied to a monochrome image forming apparatus instead of a color image forming apparatus.

  In any type of image forming apparatus, a toner image of each color may be directly transferred onto a transfer sheet or the like without using an intermediate transfer member. In other words, a transfer unit that transports transfer paper is used as an alternative to the transfer belt unit 10 described above, and a transfer belt that transfers a transfer paper is used as an alternative to the transfer belt 11 described above. It is possible to adopt a configuration in which the toner image is transferred onto the transfer paper in the process of transporting the paper.

  The image forming apparatus may form an image using ink instead of forming an image using toner. For example, an image forming apparatus that is a printing apparatus having a plate cylinder and an image forming apparatus that is an ink jet printer. When the image forming apparatus is a printing apparatus, for example, the image carrier is a plate cylinder, and the contact / separation member is a press roller and an impression cylinder.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic front view of a state in which an opening / closing part is opened with respect to the image forming apparatus main body from the state illustrated in FIG. 1. FIG. 3 is a schematic front view of a state in which the transfer belt unit is detached from the image forming apparatus main body from the state illustrated in FIG. 2. FIG. 2 is a schematic front view of a state in which the contact / separation member contact / separation device provided in the image forming apparatus illustrated in FIG. FIG. 2 is a schematic front view of a state in which the contact / separation member contact / separation device provided in the image forming apparatus illustrated in FIG. 1 releases the locked state and separates the contact / separation member from the image carrier.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Image carrier 54 Jam detection means 66 Contact / separation member, transfer member 81 Pressurization means 82 Contact / separation member support means 83 Support member 84 Holding member 85 Drive means 89 Locking member 90 Engagement / disengagement means 91 Connection member 92 Energizing means 97 Contact / separation device 100 Image forming apparatus

Claims (9)

A support member that supports a contact / separation member that is contacted / separated to / from the image carrier so as to be able to contact / separate the image carrier;
A locking member for locking the support member in a state where the contact / separation member is in contact with the image carrier;
Pressurization that presses the contact / separation member against the image carrier via the locking member and the support member in a locked state coupled to the locking member and the support member locked by the locking member. Means,
Engaging / disengaging means for forming or releasing the locking state,
When the locking state is released by the engagement / disengagement means, the pressure contact by the pressure means is released, and the contact / separation member is separated from the image carrier,
An contacting / separating member contacting / separating device that stops input from the pressurizing unit to the engaging / disengaging unit in a state where at least the locking state is formed. The contacting / separating member contacting / separating apparatus according to claim 1.
The engaging / disengaging means is connected to the supporting member and the connecting member swingably connected to the engaging member so as to engage with the connecting member and maintain the engaging state at least in the engaging state. A contact / separation member contact / separation apparatus comprising: a holding member that holds a posture of the member; and a driving unit that drives the holding member to form or release the locking state. The contact / separation member contacting / separating apparatus according to claim 2.
At least in the state in which the locking state is formed, the input to the drive unit from the pressurizing unit in the direction of driving the holding member by the drive unit is stopped. apparatus. In the contacting / separating member approaching / separating device according to any one of claims 1 to 3,
The engagement / disengagement means has a biasing means for biasing in a direction in which the locked state is released with a force large enough to maintain the locked state in the locked state. Release device. In the contacting / separating member contacting / separating device according to any one of claims 1 to 4,
The contact / separation member supporting means for supporting the contact / separation member so that the weight of the contact / separation member works in a direction in which the engagement state is released by a force large enough to maintain the engagement state in the engagement state. A contact / separation member contacting / separating device. In the contacting / separating member contacting / separating device according to any one of claims 1 to 5,
When the locking state is formed by the engaging / disengaging means, the pressurizing means urges the locking member to maintain this state, and the locking state is released by the engaging / disengaging means. The contact / separation member contacting / separating device characterized in that the locking member is biased so as to maintain this state. In the contacting / separating member contacting / separating device according to any one of claims 1 to 6,
The contact / separation member contact / separation apparatus, wherein the contact / separation member is a transfer member for transferring an image on the image carrier. In the contacting / separating member approaching / separating device according to any one of claims 1 to 7,
The engagement / disengagement is released when a jam is detected by a jam detecting means for detecting the occurrence of a jam and / or when an image for image adjustment is carried on the image carrier. Member contact / separation device.   An image forming apparatus comprising: the contacting / separating member contacting / separating device according to claim 1; and an image carrier on which the contacting / separating member contacts / separates.

Images