JP4184132B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, a paper feeding unit that feeds paper into a housing of an apparatus main body, a transfer belt unit that conveys paper fed by the paper feeding unit around the transfer belt, and being conveyed by the transfer belt unit. There is known an image forming apparatus in which an image forming unit including a photosensitive drum for forming a toner image on a certain sheet is mounted.
[0003]
  In such an image forming apparatus, one sheet is pulled out from a bundle of sheets loaded in the sheet feeding unit, and the pulled sheet is rotated around the axis while being conveyed by the transfer belt. The toner image formed on the peripheral surface of the photoconductive drum is brought into contact with the peripheral surface of the photoconductive drum so as to be transferred onto a sheet. After the transfer, the sheet is sent to a fixing device, subjected to a fixing process by heating or the like, and then discharged out of the system through a predetermined conveyance path.
[0004]
  By the way, the sheet led out from the sheet feeding unit moves while being guided by a pair of conveyance rollers provided in various places along the conveyance path and various guide members, but this movement is not performed smoothly. In addition, troubles such as so-called paper jams may occur. Conventionally, the paper feeding unit and the transfer belt unit are independent of each other as described in Patent Document 1 and Patent Document 2 in order to deal with such troubles and for maintenance such as repair and replacement of parts. It can be pulled out from the housing of the device body.
[0005]
[Patent Document 1]
  JP-A-6-16278
[Patent Document 2]
  JP 2000-275987 A
[0006]
[Problems to be solved by the invention]
  However, since the paper feeding unit and the transfer belt unit can be pulled out of the housing independently of each other, for example, the paper feeding unit is pulled out even though the paper jam occurs in the transfer belt unit. Or the transfer belt unit is pulled out even though the paper feed unit is jammed. That is, there is a problem that when the unit that is not jammed is pulled out, the drawing operation is wasted accordingly.
[0007]
  In addition, when the transfer belt unit is pulled out, the transfer belt unit needs to be separated from the photosensitive drum in the housing. For this reason, various cam mechanisms are employed between the housing and the transfer belt unit. There is also a problem that it is difficult to provide a separation mechanism that functions only by pulling out the transfer belt unit independently of the movement of the paper feeding unit in a narrow housing.
[0008]
  The present invention has been made in order to solve the above-described problems. The transfer belt unit can be pulled out from the inside of the housing to the target unit without waste during various maintenance operations, and the transfer belt unit can be used during the insertion / removal operation. It is an object of the present invention to provide an image forming apparatus that can simplify the contact / separation mechanism with respect to the photosensitive drum, thereby reducing the cost of the apparatus.
[0009]
[Means for Solving the Problems]
  According to the first aspect of the present invention, a paper feed unit that feeds paper, a paper transport unit that transports paper fed by the paper feed unit, and a toner image is formed on the paper transported by the paper transport unit. In an image forming apparatus in which an image forming unit including a photosensitive drum is mounted in a housing of an apparatus main body, the paper feeding unit and the paper transport unit are configured to be detachable integrally with the housing. The paper transport unit is mounted in a positioning state with respect to the paper feeding unit, the paper feeding unit is mounted in a positioning state on the housing, and the paper feeding unit is mounted in the housing. In this state, the paper transport unit is positioned at a contact position where the paper transport surface contacts the peripheral surface of the photosensitive drum, while the paper feed unit is pulled from the housing. Positioning means is provided for positioning the paper transport unit at a separated position where contact of the paper transport surface with the circumferential surface of the photosensitive drum is eliminated as the paper transport unit is moved in the ejecting direction. Provided in, Including at least a pair of guide rails extending in the insertion / removal direction of the paper feed unit and fixed to the opposing inner wall surfaces of the housing so as to face each other,A first guide portion for guiding the paper transport unit between a contact position and a separation position;At least a pair of protrusions projecting in opposite directions from the paper transport unit so as to be guided on the guide railsA first guided portion;Including a pair of guide grooves recessed in the up and down direction on the opposing inner wall surfaces of the sheet feeding unit,A second guide part for guiding the lifting and lowering of the paper transport unit;A pair of protrusions projecting in opposite directions from the paper transport unit so as to be guided by the guide grooves.A second guided portion;A biasing means provided between the paper transport unit and the paper feed unit and biasing the two so as to be separated from each other in the insertion / removal direction with respect to the housing; and provided in the paper feed unit; Lock means for restricting movement in the pulling-out direction from the body, and a stop portion provided at a terminal position of the guide rail and stopping the first guided portion, wherein the first groove in the guide groove (2) The biasing force is applied from the biasing unit while allowing the guided portion to move in the vertical direction, whereby the paper transport unit is positioned in the front-rear direction with respect to the paper feeding unit. Due to the stopping of the first guided part with the urging force to the stopping part and the restriction of the sheet feeding unit from the casing by the locking means, Me-decided is carried outIt is characterized by that.
[0010]
  According to the present invention, the paper feed unit and the paper transport unit are integrally pulled out of the housing during various maintenance operations such as paper jams and parts replacement. Therefore, for example, even when a paper jam has occurred in one of the paper feed unit and the paper transport unit, but it is unclear which one has occurred, both units are pulled out together. If both units can be pulled out separately, the unit without the paper jam may be pulled out, which may result in useless operations. Occurrence is prevented, and a paper drawer unit and a paper transport unit can be pulled out without waste.
[0011]
  Also, if only one of the paper feed unit and paper transport unit is pulled out of the housing when a paper jam occurs, there may be a problem that the paper straddling between both units breaks. Such inconveniences are surely prevented by pulling out the two at the same time.
[0012]
  The paper transport unit is mounted on the paper feed unit in a positioned state, and the paper feed unit is mounted on the housing in a positioned state. Therefore, the paper transport unit is mounted on the paper feed unit. Positioning is performed with respect to the paper feed unit, and by mounting the paper feed unit with the paper transport unit mounted on the housing, the paper feed unit is positioned with respect to the housing. With only one operation of mounting on the housing, the paper transport unit is positioned on the housing via the paper feed unit, and the operability for positioning is improved.
[0013]
  Further, the paper transport unit is positioned in a contact position where the paper transport surface is in contact with the peripheral surface of the photosensitive drum while the paper feed unit is mounted in the housing, while the paper feed unit is in the housing. Positioning means is provided for positioning the paper transport unit at a separated position where the contact of the paper transport surface with the peripheral surface of the photosensitive drum is eliminated as the paper transport unit is moved in the direction of being pulled out from.
[0014]
  Accordingly, by mounting the paper feed unit with the paper transport unit mounted in the housing, the paper transport unit is set in a contact posture to contact the photosensitive drum by the action of the positioning means, while the paper feed unit is By pulling out from the housing, the paper transport unit is changed to a canceling posture in which the contact with the photosensitive drum is canceled by the action of the positioning means.
[0015]
  In this way, by adopting the positioning means, the paper transport unit automatically changes its posture between the canceling posture and the contact posture simply by moving the paper feeding unit in and out of the housing. Therefore, it is not necessary to separately perform the contact / separation operation with respect to the photosensitive drum, and the operability of the entry / exit operation with respect to the housings of both units is improved accordingly.
[0016]
  Further, the positioning means is provided in the housing., Including at least a pair of guide rails extending in the insertion / removal direction of the paper feed unit and fixed to the opposing inner wall surfaces of the housing so as to face each other,A first guide portion for guiding the paper transport unit between a contact position and a separation position;At least a pair of protrusions projecting in opposite directions from the paper transport unit so as to be guided on the guide railsA first guided portion;Including a pair of guide grooves recessed in the up and down direction on the opposing inner wall surfaces of the sheet feeding unit,A second guide part for guiding the lifting and lowering of the paper transport unit;A pair of protrusions projecting in opposite directions from the paper transport unit so as to be guided by the guide grooves.And a second guided portion.
[0017]
  According to such a configuration, when the paper feeding unit is pushed into the housing, the first guided portion fixed to the paper transport unit advances while being guided by the first guide portion fixed to the housing. The paper transport unit changes its position from a separated position separated from the photosensitive drum to a contact position that contacts the photosensitive drum. The paper feed unit is provided with a second guide portion that guides the lifting and lowering of the paper transport unit, and the paper transport unit has a second guided portion fixed so as to be guided by the second guide portion. Since the section is provided, the paper transport unit is lifted and lowered in a state where movement in the insertion / removal direction is restricted with respect to the paper feed unit, and thereby the position of the paper transport unit can be changed.
[0018]
  As described above, the first and second guide portions and the first and second guided portions are provided in the paper transport unit and the paper feed unit, respectively, so that the paper transport unit moves in the forward / backward direction according to the advance / retreat of the paper feed unit. It is possible to move while being guided by the respective guide portions in two dimensions in the vertical direction, and the position change between the contact position and the separation position of the paper transport unit can be performed reliably and easily.
[0019]
  further,When the paper feed unit is pushed into the housing, the first guided member fixed to the paper transport unitPartAdvances while being guided by a guide rail fixed to the opposing wall surface in the housing, so that the paper transport unit changes its position from a separated position away from the photosensitive drum to a contact position that contacts the photosensitive drum. The paper feed unit is provided with a guide groove for guiding the lifting and lowering of the paper transport unit, and the paper transport unit is provided with a second guided portion provided so as to be guided by the guide groove.PartTherefore, the paper transport unit can be moved up and down in a state where movement in the insertion / removal direction with respect to the paper feed unit is restricted, whereby the paper transport unit is moved between the contact position and the separation position. The position can be changed between.
[0020]
  And, in this way, by forming the first guide part, the first guided part, the second guide part and the second guided part by the guide rail, the first guide body, the guide groove and the second guide body, respectively, Contributes to the simplification of the position change structure of the paper transport unit.
[0021]
  In addition to the above configuration, thisThe inventionProvided between the paper transport unit and the paper feed unit An urging means for urging both of them to move away from each other in the insertion / removal direction with respect to the housing, and a locking means that is provided in the paper feeding unit and restricts movement in the pulling direction from the housing; A stopper portion that is provided at a terminal position of the guide rail and that the first guided portion stops, and allows the second guided portion to move in the vertical direction in the guide groove, By applying an urging force from the urging means, the paper conveying unit is positioned in the front-rear direction with respect to the paper feeding unit, and the stop of the first guided portion with the urging force of the urging means is performed. Positioning of the paper transport unit with respect to the housing is performed by the locking to the section and the regulation of the drawer of the paper feeding unit from the housing by the locking means.
[0022]
  By having this configurationThe paper transport unit and the paper feed unit are stretched in the opposite directions between the locking means and the stopper at the terminal position of the first guided part by the urging force of the urging means. Therefore, the paper transport unit has a higher positioning accuracy with respect to the photosensitive drum in the housing.
[0023]
  Claim 2The described inventionClaim 1In the described invention, the paper transport unit is configured by a transfer belt unit having a transfer belt stretched between a drive roller and a driven roller, and the first guided body includes a drive shaft of the drive roller and a driven roller. It is formed by projecting outward from a driven shaft concentrically.
[0024]
  According to the present invention, since the first guided body is formed by projecting outward from the drive shaft of the drive roller and the driven shaft of the driven roller, the first guided body is formed. Compared with the case where the paper transport unit is provided on a predetermined frame or the like, the positioning accuracy is improved by not passing through the frame or the like.
[0025]
  Claim 3The described inventionClaim 1 or 2In the invention described in (1), the first guide portion is set to a short length so as to guide the paper transport unit only immediately before the paper transport unit is positioned in the housing. is there.
[0026]
  According to the present invention, the first guide portion is set to have a short length so as to guide the paper transport unit only before the paper transport unit is positioned in the housing, whereby the paper transport unit is inserted into the housing. Since the temporal contact ratio of the first guided body with respect to the first guide portion at the time of detachment operation becomes very small, it becomes possible to reduce damage due to wear of the first guided body, and stable positioning accuracy can be achieved. It can be maintained for a long time.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
  First, an outline of an image forming apparatus according to the present invention will be described. FIG. 1 is a side sectional view conceptually showing one embodiment of an image forming apparatus according to the present invention.
[0028]
  As shown in FIG. 1, the image forming apparatus 10 includes an image forming unit 20 that plays a central role, a transfer belt unit 30 disposed below the image forming unit 20, and the transfer belt unit 30 mounted thereon. A paper supply unit 40, a paper storage unit 50 for storing paper to be sent between the image forming unit 20 and the transfer belt unit 30 through the paper supply unit 40, and the image forming unit 20 and the transfer belt. The fixing device 60 disposed on the downstream side of the unit 30 (left side in FIG. 1) is formed by being housed in a box-shaped main body housing 11 having a rectangular parallelepiped shape in appearance.
[0029]
  The image forming unit 20 performs a toner image transfer process on paper supplied from the paper storage unit 50 via the paper supply unit 40. In the present embodiment, the image forming unit 20 performs upstream processing (right side in FIG. 1). ) To the downstream side, an image forming unit 20 comprising a yellow unit 20Y, a magenta unit 20M, a cyan unit 20C, and a black unit 20K is provided. Each unit 20Y, 20M, 20C, 20K is positioned and mounted in a predetermined relative positional relationship with respect to the main body casing 11 and each part.
[0030]
  Each unit 20Y, 20M, 20C, and 20K is provided with a developing device 21 and a photosensitive drum 22, respectively. Each photoconductor drum 22 is supplied with toner from the corresponding developing device 21 and rotates in the clockwise direction in FIG.
[0031]
  A charging unit 23 is provided at a position on the upper left side in FIG. 1 of each photosensitive drum 22, and an exposure unit 24 is provided at a position on the upper right side in FIG. Each photosensitive drum 22 is uniformly charged at its peripheral surface by the charging unit 23, and LED light based on image data input from a reading device (not shown) is charged from each exposure unit 24 to the photosensitive member after charging. By irradiating the peripheral surface of the drum 22, an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 22. By supplying toner from the toner container of the developing device 21 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 22.
[0032]
  The transfer belt unit 30 is provided at a position below the image forming unit 20 so as to correspond to each photosensitive drum 22. The transfer belt unit 30 includes a base 31 that is mounted on the drawer 20 and a transfer belt 32 that is supported by the base 31 and circulates counterclockwise in FIG. The transfer belt 32 includes a drive roller 32a provided at the right end of the base 31 in FIG. 1, a driven roller 32b provided at the right end, and a slightly upper position between the drive roller 32a and the driven roller 32b. It is wound around four transfer rollers 32c arranged at a pitch, and circulates by the rotational drive of the drive roller 32a.
[0033]
  Each of the transfer rollers 32c is pressed against the corresponding photosensitive drum 22 via the transfer belt 32, so that the transfer from the photosensitive drum 22 to the sheet conveyed by the transfer belt 32 is reliably performed. It has become. Further, a cleaning mechanism 25 for removing residual toner on the circumferential surface of the photosensitive drum 22 and cleaning it is provided at a lower right position in FIG. 1 of each photosensitive drum 22. The peripheral surface of the photosensitive drum 22 cleaned by the cleaning mechanism 25 is directed to the charging unit 23 for a new charging process.
[0034]
  The sheet feeding unit 40 picks up one sheet at a time from a bundle of sheets loaded in the sheet storage unit 50 and sends it between the photosensitive drum 22 and the transfer belt 32. In the present invention, the transfer belt unit The main body housing 11 is inserted and removed integrally with the main body housing 11. The sheet feeding unit 40 is disposed at a position facing a predetermined pair of conveying rollers 43 for conveying the uppermost sheet picked up from the sheet bundle in the sheet storage unit 50 and the transfer belt 32 and the photosensitive drum 22. Then, a registration roller pair 44 and the like for feeding the paper after positioning the paper are provided.
[0035]
  Then, the paper picked up from the paper storage unit 50 is supplied onto the transfer belt 32 via the conveying roller pair 43 and the registration roller pair 44, and the image forming unit 20 and the transfer belt unit are rotated along the circumference of the transfer belt 32. The toner images on the photosensitive drums 22 of the units 20Y, 20M, 20C, and 20K are sequentially transferred onto the paper during the passage.
[0036]
  Next, the sheet on which the toner image has been transferred is introduced into a fixing device 60 having a fixing roller pair 61, and the toner is fixed on the sheet by heat fixing processing by passing between the heated fixing roller pair 61. A color image is formed. The sheet with the color image that has undergone the fixing process is discharged to a discharge unit 12 formed on the top of the main body casing 11 through a predetermined conveyance path.
[0037]
  Hereinafter, the transfer belt unit 30 and the paper feeding unit 40 will be described in more detail with reference to FIG. 2 while referring to FIG. 1 and FIG. FIG. 2 is a perspective view conceptually showing an embodiment of the transfer belt unit 30 and the paper feed unit 40, and shows a state where the paper feed unit and the transfer belt unit pulled out from the housing are separated from each other. .
[0038]
  FIG. 3 is a detailed perspective view of the transfer belt unit 30 shown in FIG. 4 and 5 are detailed perspective views of the paper feed unit 40 shown in FIG. 2. FIG. 4 is a view of the paper feed unit main body 41 seen from the outer surface side, and FIG. It is the figure seen from the side. FIG. 6 is a detailed perspective view showing the positioning unit 130 provided on the inner wall surface 11 a of the main body housing 11. Further, FIG. 7 is a detailed perspective view showing a state in which the transfer belt unit 30 is attached to the paper feeding unit 40.
[0039]
  First, as shown in FIGS. 2 and 3, the transfer belt unit 30 includes a base 31 and a transfer belt 32 supported by the base 31 via a driving roller 32a, a driven roller 32b, and a transfer roller 32c. About having comprised, it is as having demonstrated based on FIG. 1 previously. The base 31 includes a pair of horizontal frames 31a in the width direction extending in the paper conveyance direction, and a pair of vertical frames 31b in the front-rear direction (paper conveyance direction) provided between the ends of the pair of horizontal frames 31a. The drive roller 32a, the driven roller 32b, and the transfer roller 32c are all pivotally supported so as to be rotatable around a predetermined axis provided between the horizontal frames 31a.
[0040]
  Each horizontal frame 31a of the base 31 has a pair of front end side positioned pins in the width direction projecting from the front end portions (end portions on the paper transport direction side) in a direction perpendicular to the paper transport direction. (First guided portion) 33 is provided, and a pair of rear end side positioned pins in the width direction (first guided portion) projecting in parallel with the front end side positioned pin 33 at each rear end portion. 34 is provided. These positioning pins 33 and 34 are guided by guide rails (first guide portions) 13 (to be described later) of the main body housing 11 when the transfer belt unit 30 is mounted on the main body housing 11. Positioning of the transfer belt unit 30 mounted in the main body housing 11 is performed.
[0041]
  In the present embodiment, a support shaft of an auxiliary roller (driven roller) 32d provided immediately downstream of the most downstream transfer roller 32c, and a portion that protrudes outward through the horizontal frame 31a. A portion of the driven shaft of the driven roller 32b that protrudes outward through the horizontal frame 31a is used as the rear end side positioned pin 34, and is used as the front end side positioned pin 33. Thus, the front end side positioned pin 33 is positioned above the rear end side positioned pin 34.
[0042]
  In addition, a pair of guided protrusions (second guided bodies) 35 in the width direction projecting outward are provided at a substantially central position in the front-rear direction of the horizontal frame 31a. The guided projection 35 is inserted into a guide groove (second guide portion) 45 described later of the paper feeding unit 40. In addition, the vertical frame 31b on the rear side (left side in FIG. 3) is provided with a pair of pressed portions 31c in the width direction formed by recessing appropriate positions on each end side. The pressed part 31c will be described later. Further, flange portions 39 extending in the front-rear direction and projecting outward are provided at the upper edge portions of the respective horizontal frames 31a.
[0043]
  As shown in FIGS. 2 and 4, the paper feed unit 40 is downstream of the paper feed unit main body 41 and the positions below both ends of the paper feed unit main body 41 in the width direction (left side in FIGS. 2 and 4). And a pair of support arms 42 in the width direction projecting from the head. The conveyance roller pair 43 is provided in the lower part of the paper feed unit main body 41, and the registration roller pair 44 is provided in the upper part. In the example shown in FIG. 4, one roller of the conveyance roller pair 43 is provided on the paper feed unit main body 41 side, while the other roller is provided on the unillustrated lid body side of the main body housing 11. The pair of transport rollers 43 can be obtained by closing the lid with the paper feed unit 40 mounted in the main body casing 11.
[0044]
  The pair of support arms 42 are set so that the distance between them is slightly wider than the width of the transfer belt unit 30, and the transfer belt unit 30 is fitted between the support arms 42 from above, whereby the transfer belt unit 30. A flange portion 39 provided on each horizontal frame 31a of the base 31 abuts on an upper edge portion of each support arm 42, whereby the transfer belt unit 30 is supported by the paper feed unit 40. Yes.
[0045]
  Each support arm 42 is provided with a concave bottomed guide groove 45 in a side view in which the inner side openings face each other at the tip position and the upper surface also opens. These guide grooves 45 correspond to the guide protrusions 35 of the transfer belt unit 30, and each transfer target unit 45 is fitted between the pair of support arms 42 of the paper feed unit 40. The installation position is set so that the guide protrusion 35 can be fitted.
[0046]
  When the guided projection 35 is fitted into the guide groove 45, the transfer belt unit 30 is attached to the paper feeding unit 40 as shown in FIG. Positioning in the front-rear direction is performed while allowing movement in the direction.
[0047]
  Further, in a state where the transfer belt unit 30 is mounted between the support arms 42, the portion corresponding to the rear vertical frame 31 b of the base 31 in the sheet feeding unit main body 41, the pressed portions 31 c (FIG. 3). ) Is provided with a pair of pressing members 36 in the width direction as shown in FIGS. 1 and 5. The pressing member 36 includes a pressing piece 36a that is slidable in the front-rear direction with respect to the sheet feeding unit main body 41 and a coil spring 36b that presses the pressing piece 36a forward. Yes. The pressing piece 36a presses the pressed portion 31c forward by the urging force of the coil spring 36b.
[0048]
  Accordingly, the transfer belt unit 30 attached to the paper feeding unit 40 is pressed forward by the pressing member 36 so that the front surface of the guided projection 35 comes into contact with the front surface of the guide groove 45 of the support arm 42, thereby transferring the transfer belt. A reliable positioning state in the front-rear direction with respect to the sheet feeding unit 40 of the unit 30 is realized.
[0049]
  A lock member (lock means) 37 is provided on each end surface of the paper feed unit main body 41 at a position slightly above the support arm 42. The lock member 37 is for locking the paper feed unit 40 mounted in the main body housing 11 so that it can be inserted and removed, and extends toward the front which is pivotally supported around the support shaft 37a. The lock rod 37b includes a lock claw 37c formed at the tip of the lock rod 37b, and a coil spring 37d that urges the lock rod 37b upward. A stopper (not shown) for maintaining the lock rod 37b in a substantially horizontal position against the urging force of the coil spring 37d is provided at a suitable end face of the paper feed unit main body 41.
[0050]
  The lock claw 37c is formed by projecting upward from the tip of the lock rod 37b. The lock claw 37c has a locking edge 37e that rises from the tip of the lock rod 37b, and an inclined edge 37f that is inclined forward and downward from the upper end of the locking edge 37e. .
[0051]
  Then, by pushing the paper feeding unit 40 into the main body casing 11, the inclined edge portion 37f of the lock claw 37c comes into sliding contact with a locking pin 16 (described later) projecting from the inner wall surface 11a of the main body casing 11. As a result, the lock rod 37b rotates counterclockwise in FIG. 1 around the one end support shaft 37a against the urging force of the coil spring 37d, and then the upper end of the inclined edge portion 37f passes the locking pin 16 and continues. The lock claw 37c is engaged with the locking pin 16 by the clockwise rotation of the lock rod 37b by the urging force of the coil spring 37d, and thereby the paper feed unit 40 pushed into the main body housing 11 is locked. It is like that.
[0052]
  The lock member 37 is provided with an operation piece 38 projecting rearward from the lock rod 37b. By operating the operation piece 38, the engagement of the lock claw 37c with the locking pin 16 is released. To get. Incidentally, in the example shown in FIG. 4, an operation lever 38a for operating the operation piece 38 by a predetermined link structure is provided so as to face the rear outside of the paper feed unit main body 41, and the engagement lever 38a is pressed to operate the engagement lever 38a. It can be canceled.
[0053]
  On the other hand, as shown in FIG. 2, two sets (widths) corresponding to the positioning pins 33 and 34 of the transfer belt unit 30 are formed on the inner wall surface 11a of the side wall of the main body casing 11 extending in the front-rear direction. Two guide rails 13 are provided which are opposed to each other in the direction. That is, in this embodiment, the front guide rail (first guide portion) 14 corresponding to the front end side positioned pin 33 as the guide rail 13 and the rear guide rail (first guide) corresponding to the rear end side positioned pin 34 are used. Part) 15 is adopted.
[0054]
  These guide rails 13 are formed in a lateral U shape so that the opening faces the entrance side of the main body housing 11, and the linear rail 13a extending in the horizontal direction and the opening side of the linear rail 13a are downward. And an upper rail 13c which is parallel to the linear rail 13a facing the rails 13a and 13b at the upper side.
[0055]
  The clearance dimension between the straight rail 13a and the upper rail 13c (pin fitting insertion space 13d) of the front guide rail 14 is set slightly larger than the diameter dimension of the front end side positioning pin 33, and the rear guide The clearance dimension between the linear rail 13a of the rail 15 and the upper rail 13c (pin fitting insertion space 13d) is set slightly larger than the diameter dimension of the rear end side positioned pin 34. In the example shown in FIG. 6, the front guide rail 14 is not provided with the inclined rail 13b.
[0056]
  Each of the straight rails 13a of the front guide rail 14 and the rear guide rail 15 has the front end side positioned pin 33 and the rear end side positioned pin 34 corresponding to these fitted in the pin insertion space 13d, and The height level is set so that the upper surface of the transfer belt 32 comes into contact with the photosensitive drum 22 of the image forming unit 20 in a state where it is in contact with the arc-shaped stop portion 13e.
[0057]
  In the example shown in FIGS. 1 and 2, each of the inclined rails 13 b of the front guide rail 14 and the rear guide rail 15 has the lowest position of the lowest position on the paper feed unit 40. The inclination angle and the length dimension are set so as to be below the front end side positioned pin 33 and the rear end side positioned pin 34 of the transfer belt unit 30.
[0058]
  Accordingly, when the paper feeding unit 40 on which the transfer belt unit 30 is mounted is pushed into the main body casing 11, the front end side positioned pin 33 and the rear end side positioned pin 34 are simultaneously moved to the front guide rail 14 and By abutting against the inclined rail 13b of the rear guide rail 15 and continuing the pushing operation, the front end side positioned pin 33 and the rear end positioned pin 34 are respectively guided to the inclined rail 13b and lifted. It is introduced into the insertion space 13d.
[0059]
  The positioned pins 33 and 34 are supported by the linear rails 13a while being in contact with the corresponding stoppers 13e of the corresponding guide rails 14 and 15, whereby the transfer belt 32 is moved. As shown in FIG. 1, the image forming unit 20 comes into contact with the photosensitive drum 22.
[0060]
  In addition, locking pins 16 corresponding to the lock members 37 of the paper feeding unit 40 are provided on the inner wall surfaces 11 a opposed to the side walls of the main body housing 11 in the opposing direction. The height of the locking pin 16 is set so that the inclined edge 37f of the lock claw 37c of the lock member 37 is opposed to the lock pin 37 in a state where the paper feeding unit 40 is mounted in the main body casing 11. Therefore, by pushing the paper feeding unit 40 into the main body casing 11, the inclined edge portion 37f is brought into sliding contact with the locking pin 16, so that the lock member 37 once rotates around the support shaft 37a in a predetermined direction. The locking edge portion 37e comes into contact with the locking pin 16 and the mounting state of the paper feeding unit 40 in the main body housing 11 is locked.
[0061]
  In this embodiment, the guide rail 13 and the locking pin 16 are formed in a positioning unit 130 as shown in FIG. The positioning unit 130 is attached to each inner wall surface 11a parallel to the sheet conveyance direction of the main body housing 11 by screwing or the like in a state of being opposed to each other, and includes a front end side positioned pin 33 and a front end side positioned pin. Corresponding to the installation position of 33, it is formed long in the paper transport direction.
[0062]
  The front guide rail 14 is provided at the upper edge of the positioning unit 130 in the front (left side in FIG. 6), and the rear guide rail 15 is provided at the rear position and slightly below the front guide rail 14. It has been.
[0063]
  By adopting such a positioning unit 130, it is not necessary to provide the guide rail 13 and the locking pin 16 directly on the inner wall surface 11a of the main body casing 11 with high accuracy, and the manufacturing efficiency can be improved while ensuring the accuracy. Contribute to improvement.
[0064]
  The relative positional relationship between the rear guide rail 15 and the locking pin 16 shown in FIG. 6 (the locking pin 16 is positioned below the rear guide rail 15) is shown in FIG. Although the relative positional relationship between the rear guide rail 15 and the locking pin 16 (the locking pin 16 is located above the rear guide rail 15) is different, these positional relationships are This is a design matter appropriately set according to the situation, and does not have an important meaning in the present invention.
[0065]
  Further, in the paper feeding unit 40 shown in FIGS. 4 and 5, a positioning pair 46 constituted by a pair of upper and lower portions is provided on the outer surface of the front end portion of the support arm 42 so as to project outward, and the locking member 37. A positioning shaft 47 formed by extending the support shaft 37a toward the outside is provided, while the positioning unit 130 of the main body housing 11 corresponds to the positioning pair 46 in FIG. Positioning protrusions 13 f extending in the front-rear direction as shown, and positioning concave pieces 13 g opened corresponding to the positioning shaft 47 are provided.
[0066]
  The positioning pair 46 is set so that the vertical gap dimension is slightly larger than the vertical width dimension of the positioning protrusion 13f, and the positioning concave piece 13g is fitted with the positioning shaft 47 in the sliding contact state. Are dimensioned to fit.
[0067]
  Therefore, when the paper feeding unit 40 is inserted into the main body casing 11, the positioning pair 46 is fitted on the positioning protrusion 13f, and the positioning shaft 47 is fitted on the positioning concave piece 13g. The mounting state of the paper unit 40 in the main body housing 11 is stabilized.
[0068]
  Hereinafter, the operation of the image forming apparatus 10 according to the present embodiment will be described. FIG. 8 is a side sectional view for explaining the operation of the present embodiment. FIG. 8A is a state in which the paper feeding unit 40 to which the transfer belt unit 30 is attached is pulled out from the main body housing 11. (B) shows a state in which the paper feed unit 40 is mounted in the main body casing 11.
[0069]
  First, as shown in FIG. 8A, in the state where the paper feeding unit 40 is pulled out from the main body housing 11, the transfer belt unit 30 has its guided projection 35 supported by the supporting arm of the paper feeding unit 40 by its own weight. The guide groove 45 is recessed to the bottom of the guide groove 45, so that the distance between the upper surface of the transfer belt 32 and the peripheral surface of the photosensitive drum 22 of the image forming unit 20 is set at a separated position. It is in the state that was done.
[0070]
  Further, since the transfer belt unit 30 is pressed forward (leftward in FIG. 8) by the pressing member 36 of the paper feeding unit 40, the guided projection 35 is abutted against the front edge of the guide groove 45. As a result, a positioning state in the front-rear direction with respect to the sheet feeding unit 40 is ensured.
[0071]
  When the paper feeding unit 40 is pushed into the image forming apparatus 10 in this state, the front end side positioned pins 33 and the rear end side positioned pins 34 of the transfer belt unit 30 are positioned on the inner wall surface 11 a of the main body housing 11. The front and rear guide rails 13 (the front guide rail 14 and the rear guide rail 15) provided via the unit 130 come into contact with the upper surface of the inclined rail 13b.
[0072]
  After this contact, when the pushing operation of the paper feeding unit 40 into the main body housing 11 is continued, the front end side positioned pin 33 and the rear end side positioned pin 34 are moved to the front guide rail 14 and the rear guide rail 15 respectively. The transfer belt unit 30 is gradually raised by being guided by the inclined surface of the inclined rail 13b.
[0073]
  When the front end side positioned pin 33 and the rear end side positioned pin 34 reach the linear rails 13a of the front guide rail 14 and the rear guide rail 15, respectively, the transfer belt unit 30 has the transfer belt 32 as an image forming unit. It will be in the state contact | abutted to 20 surrounding surfaces.
[0074]
  In this state, by continuing the pushing operation of the paper feeding unit 40, the front end side positioned pin 33 and the rear end side positioned pin 34 slide on the linear rails 13a of the front guide rail 14 and the rear guide rail 15. Then, it advances in the pin insertion space 13d and stops at the stopper 13e. If the pushing operation of the paper feeding unit 40 is further continued regardless of this stoppage, the paper feeding unit 40 further proceeds against the urging force of the coil spring 36b of the pressing member 36, whereby the lock member 37 is locked. The inclined edge portion 37f of the claw 37c contacts the locking pin 16 provided on the inner wall surface 11a of the main body housing 11 via the positioning unit 130. Due to the interference with the locking pin 16, the lock member 37 rotates counterclockwise around the support shaft 37a against the urging force of the coil spring 37d.
[0075]
  Thereafter, when the locking claw 37c passes the locking pin 16, the locking member 37 is rotated clockwise around the support shaft 37a by the biasing force of the coil spring 37d, and thereby the locking edge 37e of the locking claw 37c. Is engaged with the locking pin 16, and the mounting state of the paper feeding unit 40 in the main body casing 11 is locked as shown in FIG.
[0076]
  In this state, the paper feed unit 40 and the transfer belt unit 30 are configured such that the paper feed unit 40 is locked by the lock member 37 and the drawer is restricted, and the front end side and rear end side positioned pins 33. , 34 are respectively brought into contact with the stop portion 13e of the guide rail 13 and are thereby stretched toward each other by the urging force of the coil spring 36b of the pressing member 36, so that the transfer belt unit 30 is In the main body casing 11, the positioning in the front-rear direction is surely performed, and the guided projection 35 is raised in advance by being guided by the guide groove 45. A reliable positioning is achieved in both directions.
[0077]
  In the state in which the transfer belt unit 30 is positioned in the main body housing 11, the guided projection 35 is separated from the groove walls before and after the guide groove 45 of the paper feeding unit 40 and is substantially at the center as shown in FIG. It is in the state located in the part.
[0078]
  When pulling out the paper feeding unit 40 shown in FIG. 8 (B), which is mounted in the locked state in the main body casing 11 in this manner, from the main body casing 11, the operation piece 38 is operated to release the lock member 37. What is necessary is just to rotate counterclockwise around the support shaft 37a. By doing so, the engagement of the lock claw 37c with the locking pin 16 is released, so that the paper feed unit 40 can be pulled out from the main body housing 11.
[0079]
  As described in detail above, the image forming apparatus 10 of the present invention includes a paper feeding unit 40 that feeds paper, and a transfer belt unit that conveys the paper fed by the paper feeding unit 40 around the transfer belt 32. 30 and an image forming unit 20 including a photosensitive drum 22 that forms a toner image on a sheet being conveyed by the transfer belt unit 30 are assumed to be mounted in the main body casing 11 of the apparatus main body. The paper feed unit 40 and the transfer belt unit 30 are configured to be integrally detachable from the main body housing 11.
[0080]
  Therefore, according to the image forming apparatus 10, the paper feeding unit 40 and the transfer belt unit 30 are integrally pulled out from the main body housing 11 during various maintenance operations such as paper jams and parts replacement. Even when a paper jam has occurred in one of the paper unit 40 and the transfer belt unit 30 but it is unclear which one has occurred, both units 30 and 40 are pulled out from the main body casing 11 at a time. be able to. Therefore, when both can be pulled out separately as in the prior art, there has been a wasteful operation of pulling out the unit without the paper jam. Occurrence is prevented, and an operation of pulling out the paper feeding unit 40 and the transfer belt unit 30 without waste can be realized.
[0081]
  Conventionally, when a paper jam occurs between the paper feeding unit 40 and the transfer belt unit 30, when only one of them is pulled out from the main body housing 11, the paper jams across both units. However, the occurrence of such a problem can be reliably prevented by pulling out both units 30 and 40 at the same time.
[0082]
  Further, the transfer belt unit 30 is connected to the paper feeding unit 40.forThe paper feed unit 40 is mounted in the main body housing 11 while being mounted in a positioned state.forSince the transfer belt unit 30 is configured to be mounted in a positioned state, the transfer belt unit 30 is positioned with respect to the paper feed unit 40 by being mounted on the paper feed unit 40 and the transfer belt unit 30 is mounted. By attaching the paper feeding unit 40 to the main body housing 11, the paper feeding unit 40 is positioned with respect to the main body housing 11, and after all, only by one operation of attaching the paper feeding unit 40 to the main body housing 11. The transfer belt unit 30 can be positioned on the main body housing 11 via the paper feed unit 40.
[0083]
  In addition, in the case where a paper jam occurs between the units 30 and 40, the transfer belt unit 30 in the external open space where both units 30 and 40 are pulled out from the main body housing 11. By loosening or releasing the mounting state of the paper feeding unit 40, the paper jam clearing operation can be performed, and the workability of the paper jam clearing operation is improved.
[0084]
  Further, in a state where the paper feeding unit 40 is mounted in the main body casing 11, the transfer belt unit 30 is positioned at a contact position where the transfer belt contacts the peripheral surface of the photosensitive drum 22, while paper feeding is performed. Positioning means is provided for positioning the transfer belt unit 30 at a separated position where the contact of the transfer belt 32 with the peripheral surface of the photosensitive drum 22 is eliminated as the unit 40 is moved in the direction of being pulled out from the main body casing 11. In this embodiment, as the positioning means, a guide rail 13 provided in the main body casing 11 for guiding the transfer belt unit 30 between the contact position and the separation position (the front guide rail 14 and the rear guide rail). A guide rail 15) and a positioning pin fixed to the transfer belt unit 30 so as to be guided by the pair of guide rails 14 and 15. 33, 34, a guide groove 45 provided in the paper feed unit 40 to guide the raising and lowering of the transfer belt unit 30, and a guided protrusion 35 fixed to the transfer belt unit 30 so as to be guided by the guide groove 45. Is adopted.
[0085]
  Therefore, when the paper feeding unit 40 is pushed into the main body housing 11, the positioning pins 33 and 34 fixed to the transfer belt unit 30 are guided by the guide rails 14 and 15 fixed to the main body housing 11. By proceeding, the transfer belt unit 30 changes its position from a separated position separated from the photosensitive drum 22 to a contact position that contacts the photosensitive drum 22. The paper feed unit 40 is provided with a guide groove 45 that guides the raising and lowering of the transfer belt unit 30, and the guided protrusion is fixed to the transfer belt unit 30 so as to be guided by the guide groove 45. 35 is provided, the transfer belt unit 30 can be moved up and down in a state where movement of the paper feed unit 40 in the insertion / removal direction with respect to the main body housing 11 is restricted. The posture can be changed.
[0086]
  By providing such positioning means over the transfer belt unit 30 and the paper feed unit 40, the transfer belt unit 30 can move each guide portion in two dimensions in the forward / backward direction and the vertical direction in accordance with the advance / retreat of the paper feed unit 40. Accordingly, the position of the transfer belt unit 30 between the contact posture and the separation posture can be easily and reliably changed.
[0087]
  The positioning state of the transfer belt unit 30 with respect to the paper feed unit 40 is determined by the pressing member.
36, the transfer belt unit 30 is positioned with respect to the paper feed unit 40 only by an operation of mounting the paper feed unit 40 in the main body housing 11, and the positioning operation is performed. Can contribute to simplification.
[0088]
  Furthermore, since the paper feed unit 40 is provided with a lock member 37 for releasably locking the mounting state of the paper feed unit 40 in the main body housing 11, the presence of the lock member 37 causes the inside of the main body housing 11. The mounted paper feed unit 40 is prevented from moving in the pull-out direction from the main body housing 11 due to vibration of the apparatus being operated or vibration due to disturbance, etc., and various interior devices are moved by the movement of the paper feed unit 40 in the pull-out direction. It is possible to effectively prevent the occurrence of a malfunction that causes the positional relationship between the two to be out of order and the apparatus to not operate normally.
[0089]
  The present invention is not limited to the above embodiment, and includes the following contents.
[0090]
  (1) In the above embodiment, the support shaft of the auxiliary roller 32d and the driven shaft of the driven roller 32b are set longer than necessary, and both end portions of these shafts are positioned on the front end side positioned pin 33 and the rear end side. Although used as the positioning pin 34, the present invention is limited to using the support shaft of the auxiliary roller 32d and the driven shaft of the driven roller 32b as the front end side positioning pin 33 and the rear end side positioning pin 34, respectively. Instead, the front end side positioned pin and the rear end side positioned pin may be provided by separately providing a dedicated one from the horizontal frame 31a.
[0091]
  (2) In the above embodiment, the pressing piece 36a of the pressing member 36 is biased by the coil spring 36b. However, the present invention is limited to the pressing of the pressing member 36 by the coil spring 36b. Instead, it may be urged by an elastic member such as a leaf spring or rubber, or various urging members such as air pressure. The same applies to the coil spring 37d that biases the lock member 37.
[0092]
  (3) In the above embodiment, an elastic member (coil spring 37d) is employed as the biasing means for biasing the lock member 37. Instead of employing the elastic member, a predetermined weight is applied to the lock member 37. A structure may be employed in which the lock member 37 is kept locked by the weight of the weight. This can contribute to a reduction in material cost because the elastic member is not used.
[0093]
  (4) In the above embodiment, the locking pin 16 protruding from the inner wall surface 11a of the main body housing 11 via the positioning unit 130 is employed as the object to which the lock claw 37c of the lock member 37 is locked. However, the present invention is not limited to the locking object of the locking claw 37c being the locking pin 16, and a locking hole is formed in a frame provided at an appropriate position in the main body casing 11. And the locking claw 37c may be locked in the locking hole.
[0094]
  (5) In the above-described embodiment, the paper feeding unit 40 is provided with the pressing member 36 and the transfer member 30 is pressed forward by the pressing member 36. The transfer belt unit 30 may be pressed in the pull-out direction in a state where the transfer belt unit 40 is mounted in the main body casing 11 by being provided in an appropriate place in the main body casing 11.
[0095]
  (6) In the above embodiment, the elastic member 17 provided at an appropriate position in the main body housing 11 can be adopted as a constituent element of the positioning means as shown in FIG. That is, the front end portion of the support arm 42 of the paper feed unit 40 is brought into contact with the elastic member 17 immediately before the paper feed unit 40 is mounted in the main body casing 11 and locked by the lock member 37. As the elastic member 17, rubber, a soft synthetic resin having elasticity, and various springs can be employed.
[0096]
  By doing so, the paper feed unit 40 mounted in the main body casing 11 and locked by the lock member 37 is pressed by the elastic member 17 in the pull-out direction by the elastic arm 17, whereby the lock member Since the locking edge 37e of 37 is in contact with the locking pin 16, reliable positioning of the transfer belt unit 30 in the main body housing 11 is realized.
[0097]
  Incidentally, when the transfer belt unit 30 is positioned by such a method, the guided protrusion 35 of the transfer belt unit 30 abuts against the front wall of the guide groove 45 of the paper feeding unit 40 by the urging force of the coil spring 36b. (In addition, since FIG. 1 illustrates the positioning state by the positioning method of the above-described embodiment, the guided protrusion 35 is in the center portion of the guide groove 45). .
[0098]
  (7) In the above embodiment, a configuration may be employed in which a manual paper feeding portion is provided in the main body casing 11 and the paper is supplied from the manual feeding portion toward the registration roller pair 44 of the paper feeding unit 40. .
[0099]
【The invention's effect】
  According to the image forming apparatus of the present invention, since the paper feeding unit and the paper transport unit mounted in the housing of the apparatus main body are configured to be integrally inserted into and removed from the housing, various types of paper jamming, parts replacement, etc. During the maintenance operation, the paper feed unit and the paper transport unit can be pulled out of the housing as one unit. For example, one of the paper feed unit and the paper transport unit has a paper jam. In such a case, it is possible to prevent a useless operation from pulling out the unit without paper jam.
[0100]
  In addition, when a paper jam occurs between the paper feed unit and the paper transport unit, if only one of them is pulled out of the housing, there is a problem that the paper straddling the two units breaks. However, the occurrence of such inconvenience can be reliably prevented by pulling out both units at the same time.
[Brief description of the drawings]
FIG. 1 is a side sectional view conceptually showing an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a perspective view conceptually showing an embodiment of a transfer belt unit and a paper feed unit.
3 is a detailed perspective view of the transfer belt unit shown in FIG. 2. FIG.
4 is a detailed perspective view of the paper feed unit shown in FIG. 2, and is a view of the paper feed unit main body as seen from the outer surface side.
5 is a detailed perspective view of the paper feeding unit shown in FIG. 2, and is a view of the paper feeding unit main body as viewed from the inner surface side.
FIG. 6 is a detailed perspective view showing a positioning unit provided in the housing.
FIG. 7 is a detailed perspective view illustrating a state in which a transfer belt unit is mounted on a paper feeding unit.
FIGS. 8A and 8B are side cross-sectional views for explaining the operation of the present embodiment. FIG. 8A is a diagram illustrating a state in which the paper feeding unit to which the transfer belt unit is attached is pulled out from the main body housing. ) Shows a state in which the paper feeding unit is mounted in the main body casing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Main body housing
11a Inner wall surface 12 Discharge part
13 Guide rail (first guide part)
14 Front guide rail (first guide part)
15 Rear guide rail (first guide part)
13a Straight rail 13b Inclined rail
13c Upper rail 13d Pin insertion space
13e Stopping part 13f Positioning protrusion
13g Positioning concave piece
16 Locking pin 17 Elastic member
20 Image forming unit 21 Developing device
22 Photosensitive drum 23 Charging part
24 Exposure unit 25 Cleaning mechanism
30 Transfer belt unit 31 Base
31a Horizontal frame 31b Vertical frame
32 Transfer belt 32a Drive roller
32b Follower roller 32c Transfer roller
32d Auxiliary roller (driven roller)
33 Positioning pin on the front end side (first guided part)
34 Rear end side positioning pin (first guided part)
35 Guided protrusion (second guided body)
36 Pressing member 37 Locking member
37a Support shaft 37b Lock rod
37c Lock claw 37d Coil spring
37e Locking edge 37f Inclined edge
38 Operation piece 39 Flange
40 Paper Feed Unit 41 Paper Feed Unit Body
42 Supporting arm 43 Conveying roller pair
44 Registration roller pair 45 Guide groove (second guide part)
46 Positioning pair 47 Positioning axis
50 Paper storage unit 60 Fixing device
61 Fixing roller pair

Claims (3)

An image provided with a sheet feeding unit for feeding sheets, a sheet conveying unit for conveying sheets fed by the sheet feeding unit, and a photosensitive drum for forming a toner image on the sheets conveyed by the sheet conveying unit In the image forming apparatus in which the forming unit is mounted in the casing of the device main body,
The paper feed unit and the paper transport unit are configured to be integrally inserted into and removed from the housing, and the paper transport unit is mounted in a positioning state with respect to the paper feed unit. Is mounted in a positioning state on the housing,
With the paper feed unit mounted in the housing, the paper transport unit is positioned at a contact position where the paper transport surface comes into contact with the peripheral surface of the photosensitive drum, while the paper feed unit is in the housing. Positioning means is provided for positioning the paper transport unit at a separated position where contact of the paper transport surface with the peripheral surface of the photosensitive drum is eliminated as it is moved in the direction of being pulled out from the body;
The positioning means includes
And at least a pair of guide rails which are provided in the housing and extend in the insertion / removal direction of the paper feeding unit and are fixed to the opposing inner wall surfaces of the housing so as to face each other. A first guide part for guiding between
At least a pair of first guided portions protruding in opposite directions from the paper transport unit so as to be guided on the guide rail;
A second guide portion that includes a pair of guide grooves recessed in the up-down direction on the opposing inner wall surfaces of the paper feed unit, and guides the lifting and lowering of the paper transport unit;
A pair of second guided portions projecting in opposite directions from the paper transport unit so as to be guided by the guide groove ,
A biasing means provided between the paper transport unit and the paper feed unit, and biasing the two so as to be separated from each other in the insertion / removal direction with respect to the housing;
Locking means provided on the paper feeding unit for restricting movement in the pulling direction from the housing;
A stop portion provided at an end position of the guide rail, wherein the first guided portion stops;
The urging force is applied from the urging means while allowing the second guided portion to move in the guide groove in the vertical direction, thereby positioning the paper transport unit in the front-rear direction with respect to the paper feed unit. ,
Due to the stopping of the first guided portion with the urging force of the urging means to the stopping portion, and the restriction of pulling out of the paper feeding unit from the housing by the locking means, the paper transport unit Positioning with respect to a housing | casing is performed, The image forming apparatus characterized by the above-mentioned. The sheet conveying unit is constituted by a transfer belt unit having a transfer belt stretched between a driving roller and a driven roller, and the first guided body is concentric from the driving shaft of the driving roller and the driven shaft of the driven roller. 2. The image forming apparatus according to claim 1 , wherein the image forming apparatus is formed by projecting outward. 3. The image according to claim 1, wherein the first guide unit is set to a short length so as to guide the transport unit only immediately before the sheet transport unit is positioned in the housing. 4. Forming equipment.

Images