JP2013200512A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which can be configured to draw a developing unit along an axial direction of a photoreceptor drum with respect to a housing while a developing roller and the photoreceptor drum can be brought close to or separated from each other.SOLUTION: A color printer 1 has a body casing 2, a plurality of (four) photoreceptor drums 21 and developing rollers 26 corresponding to the photoreceptor drums 21 and comprises: a plurality of (four) developing units 16 which can be drawn from the body case 2 along an axial direction of the photoreceptor drums 21 and a cam member 90 for contacting and separating the developing rollers and the photoreceptor drums. And, the cam member 90 is disposed so as to overlap with the plurality of (four) photoreceptor drums 21 when the cam member 90 is projected on one end side of the axial direction of the photoreceptor drums and in the axial direction of the photoreceptor drums 21.

Description

  The present invention relates to an image forming apparatus employing an electrophotographic system.

  2. Description of the Related Art As an electrophotographic image forming apparatus, a color printer including a main body casing, a drum unit that is detachably attached to the main body casing along the front-rear direction, and a developing cartridge that is detachably attached to the drum unit is known. ing. The drum unit is arranged in parallel in the front-rear direction, and includes a plurality of photosensitive drums corresponding to each of a plurality of colors (yellow, magenta, cyan, black), and the developing cartridge includes a developing roller that supplies toner to the photosensitive drum. A plurality of photosensitive drums are provided correspondingly.

  In such a color printer, a configuration is known in which the developing roller of the developing cartridge is close to the photosensitive drum so that toner can be supplied when an image is formed, and is separated so that toner cannot be supplied when an image is not formed. It has been.

  As such a color printer, for example, the main body casing includes a separation pressing mechanism for contacting and separating the photosensitive drum and the developing roller, and the developing cartridge includes a developing roller at a lower end portion thereof, and an upper end portion thereof. There has been proposed a color laser printer provided with pressing protrusions pressed by a separation pressing mechanism on both sides in the axial direction of the photosensitive drum (see, for example, Patent Document 1).

  In such a color laser printer, the axial direction of the upper end portion of the developing cartridge is such that the separation pressing mechanism sandwiches the upper end portion of the developing cartridge corresponding to the pressing protrusion when the drum unit is mounted on the main body casing. Arranged on both sides. Further, the developing cartridge is attached to and detached from the drum unit along the substantially vertical direction in a state where the drum unit is pulled out from the main body casing.

JP 2007-178654 A

  However, from the viewpoint of improving the efficiency of the replacement operation of the developing cartridge, it is desired that the developing cartridge be configured to be able to be drawn out along the axial direction of the photosensitive drum with respect to the main body casing.

  However, in the color laser printer described in Patent Document 1, in the state where the drum unit is mounted on the main body casing, the separation pressing mechanism is disposed on both sides in the axial direction of the photosensitive drum with respect to the upper end portion of the developing cartridge. If the developing cartridge is pulled out from the main body casing along the axial direction of the photosensitive drum, the developing cartridge and the separation pressing mechanism may interfere with each other.

  Therefore, it is difficult to configure the developing cartridge so that it can be pulled out along the axial direction of the photosensitive drum with respect to the main body casing.

  Accordingly, an object of the present invention is to make it possible to draw the developing unit with respect to the housing along the axial direction of the photosensitive drum while allowing the developing roller and the photosensitive drum to approach and separate from each other. An object is to provide an image forming apparatus.

(1) In order to achieve the above object, an image forming apparatus according to the present invention is provided in a one-to-one correspondence with a housing, a plurality of photosensitive drums arranged in parallel at intervals, and a plurality of photosensitive drums. A plurality of developing units configured to be drawable from the casing toward the one end side in the axial direction along the axial direction of the photosensitive drum, and a casing along the parallel direction of the plurality of photosensitive drums The development roller is moved to a proximity position where the development roller approaches or contacts the corresponding photosensitive drum and a separation position where the development roller is separated from the corresponding photosensitive drum. And a configured contact / separation member.

  The contact / separation member is disposed on one end side in the axial direction of the photosensitive drum and overlaps with the plurality of photosensitive drums when projected in the axial direction.

  According to such a configuration, the contacting / separating member is disposed on one end side in the axial direction of the photosensitive drum and overlaps with the plurality of photosensitive drums when projected in the axial direction. Can be secured, and when the developing unit is pulled out from the housing in the axial direction toward the one end side in the axial direction, it is possible to suppress interference between the developing unit and the contacting / separating member.

  As a result, by moving the contact / separation member, the developing roller can be moved between the proximity position and the separation position, and the development unit can be pulled out from the housing along the axial direction of the photosensitive drum. be able to.

That is, the developing unit can be configured to be able to be pulled out along the axial direction of the photosensitive drum with respect to the housing while the developing roller and the photosensitive drum can be reliably moved closer to and away from each other.
(2) The image forming apparatus may include a drum support member that integrally supports a plurality of photosensitive drums. In this case, the contact / separation member is provided on one end side in the axial direction of the drum support member.

  According to such a configuration, since the contact / separation member is provided on one end side in the axial direction of the drum support member, when the contact / separation member is projected in the axial direction of the photosensitive drum, the plurality of photosensitive drums can be reliably connected. It can be arranged to overlap.

For this reason, when the developing unit is pulled out from the state in which the developing unit is mounted to the axial direction toward the one end side in the axial direction, it is possible to reliably suppress the interference between the developing unit and the contact / separation member.
(3) The drum support member may be configured to be drawable from the housing along the axial direction toward one end in the axial direction.

  According to such a configuration, the plurality of photosensitive drums are integrally supported by the drum support member, and the drum support member is configured to be able to be pulled out from the housing. Therefore, the plurality of photosensitive drums can be replaced at the same time. .

Therefore, compared with the case where each of the plurality of photosensitive drums is replaced separately, the efficiency of exchanging the plurality of photosensitive drums can be improved, and the maintainability of the image forming apparatus can be improved.
(4) The contact / separation member is configured to be slidable between a first position where the developing roller is disposed at the close position and a second position where the developing roller is disposed at the separated position. There may be provided an action part for guiding the developing roller to move toward the separated position when moved to.

  In this case, the developing unit is acted on the action part in a state where the contact / separation member is disposed at the second position, and the actuated part is released from the action by the action part in the state where the contact / separation member is located at the first position. It has.

  According to such a configuration, in a state where the contact / separation member is disposed at the second position, the acting portion of the contact / separation member acts on the actuated portion of the developing unit, and the contact / separation member is disposed at the first position. In the state, the action of the action part on the acting part is released.

  Therefore, the slide movement of the contact / separation member can be reliably applied to the developing unit via the action part and the acted part.

As a result, the developing roller can be reliably moved to the proximity position and the separation position by the sliding movement of the contact / separation member.
(5) Further, the developing unit is advanced toward the corresponding photosensitive drum, and the advancing position where the developing roller can be moved to the proximity position and the separating position, and the developing roller is disposed at the separating position. In addition, a moving unit configured to move to a retracted position for retracting from the advanced position so as to be further away from the corresponding photosensitive drum may be provided. In this case, the moving means is disposed on the side opposite to the photosensitive drum with respect to the developing unit.

  According to such a configuration, by arranging the developing unit at the advanced position, the developing roller is arranged so as to be movable between the close position and the separated position. Therefore, when the image is formed, the developing unit is set at the advanced position. If arranged, the developing roller and the photosensitive drum can be brought close to and separated from each other.

  Further, since the developing unit is disposed so as to be retracted from the corresponding photosensitive drum rather than the advanced position in the state of being disposed at the retracted position, the developing unit is also disposed at the advanced position with respect to the contact / separation member. In comparison, they are arranged to be retracted. Therefore, when the developing unit is pulled out from the housing along the axial direction, the developing unit and the contacting / separating member can be reliably prevented from interfering with each other if the developing unit is disposed at the retracted position.

  Further, in the state where the developing unit is disposed at the retracted position, the developing roller is disposed so as to be separated from the corresponding photosensitive drum as compared to the state disposed at the separated position. Therefore, when the developing unit is pulled out from the housing, the developing roller and the photosensitive drum can be prevented from contacting and sliding.

  Further, since the moving means is disposed on the opposite side of the developing unit with respect to the developing unit, the developing unit can be smoothly moved to the advanced position and the retracted position.

Therefore, the developing unit is placed in the advanced position, so that the developing roller and the photosensitive drum can be reliably brought close to and separated from each other. When the developing unit is placed in the retracted position, when the developing unit is pulled out of the housing The development unit and the contact / separation member can be reliably prevented from interfering with each other, and the development roller and the photosensitive drum can be prevented from sliding.
(6) Further, each of the plurality of developing units may be arranged so as not to overlap with the contact / separation member when projected in the axial direction in a state of being arranged at the retracted position.

According to such a configuration, if each of the plurality of developing units is disposed at the retracted position, each of the plurality of developing units and the contacting / separating member do not overlap when projected in the axial direction of the photosensitive drum. When the unit is pulled out from the casing along the axial direction, it is possible to more reliably suppress the interference between the developing unit and the contact / separation member.
(7) The contact / separation member is configured to act on the developing unit by movement in a state where the developing unit is disposed at the advanced position, and in the state where the developing unit is disposed at the retracted position. It may be configured such that the action on is released.

  According to such a configuration, since the movement of the contact / separation member acts on the development unit in a state where the development unit is arranged at the advanced position, the movement of the contact / separation member is reliably applied to the development roller via the development unit. Acted. Therefore, the developing roller can be reliably moved to the close position and the separated position.

On the other hand, when the developing unit is in the retracted position, the developing unit and the contacting / separating member are spaced apart so that the action on the developing unit is released. The interference between the developing unit and the contact / separation member can be more reliably suppressed.
(8) The apparatus may further comprise a drawing restricting means configured to be movable between a drawing restricting position for restricting the drawing of the developing unit to the housing and a drawing allowing position for allowing the developing unit to be drawn from the housing. . In this case, the moving means moves the developing unit from the advanced position to the retracted position as the drawer restricting means moves from the pull restricting position to the pull permitting position, and moves the pull restricting means from the pull permitting position to the pull restricting position. The developing unit is configured to move from the retracted position to the advanced position with the movement.

  According to such a configuration, the drawing unit can be allowed to be pulled out from the housing in a state where the drawing restricting unit is disposed at the drawing allowance position, and is not desired in a state where the drawing restricting unit is disposed at the drawing restricting position. The drawer of the developing unit to the housing can be restricted.

  The moving means moves the developing unit from the advanced position to the retracted position in accordance with the movement of the drawing restricting means to the drawing restricting position and the drawing allowance position, that is, the developing unit and the drawing restricting means are interlocked. If the user arranges the drawing restricting means at the drawing allowable position in order to pull out the developing unit from the housing, the developing unit is arranged at the retracted position.

  Therefore, it is possible to improve the efficiency of the operation of moving the developing unit from the advanced position to the retracted position, as compared with the case where each of the drawing restriction means and the developing unit is moved independently. In addition, by disposing the pull-out restricting unit at the pull-out allowable position in order to pull out the developing unit from the housing, the developing unit can be reliably disposed at the retracted position.

Accordingly, while the efficiency of the drawing operation with respect to the housing of the developing unit can be improved, it is possible to reliably suppress the interference between the developing unit and the contact / separation member, and to prevent the developing roller and the photosensitive drum from sliding. it can.
(9) Further, the moving means supports the slide member configured to be slidable along the axial direction in accordance with the movement of the pull-out restricting position and the pull-out allowable position of the pull-out restricting means, the developing unit, and slides An advancing / retreating member configured to be movable along an orthogonal direction orthogonal to both the axial direction and the parallel direction by sliding the member may be provided. In this case, the advancing / retreating member moves the developing unit from the advanced position to the retracted position by the sliding movement of the slide member accompanying the movement of the pulling restricting means from the pulling restricting position to the pulling allowable position, and the drawing restricting position of the pulling restricting means The developing unit is moved from the retracted position to the advanced position by the sliding movement of the sliding member accompanying the movement from the retracting position to the drawing restriction position.

  According to such a configuration, the slide member is slid along with the movement of the pull-out restricting means, and the advance / retreat member moves the developing unit to the advanced position and the retracted position by the slide movement of the slide member.

Therefore, the movement of the drawing restricting means and the movement of the developing unit can be reliably interlocked via the slide member and the advance / retreat member.
(10) In addition, one of the slide member and the advance / retreat member is provided with a protrusion that protrudes toward the other side along the orthogonal direction, and a groove corresponding to the protrusion is formed on the other. Also good. In this case, the protrusion and the groove are fitted in the state where the pull-out restricting means is disposed at the pull-out permitted position, and the protrusion and the groove are fitted in the state where the pull-out restricting means is disposed at the pull-out restricting position. Canceled.

  According to such a configuration, in the state where the drawing restricting means is arranged at the drawing restricting position, the protrusion is released from the fitting with the groove, and thus comes into contact with either the slide member or the advance / retreat member.

  Therefore, the advance / retreat member is advanced along the orthogonal direction corresponding to the protrusion amount of the protrusion so that the developing unit is disposed at the advance position.

  On the other hand, the protrusion is fitted with the groove in a state where the pull-out restricting means is disposed at the pull-out allowable position.

  Therefore, the advance / retreat member is retracted along the orthogonal direction so that the developing unit is disposed at the retracted position.

That is, the advance / retreat member can be reliably moved along the orthogonal direction, and the developing unit can be reliably moved to the retracted position and the advanced position.
(11) Further, at least one of the protrusion and the groove may be formed with an inclined portion that is inclined toward the photosensitive drum side in the orthogonal direction from the upstream side in the drawing direction to the downstream side in the drawing direction. Good.

According to such a configuration, although the configuration is simple, when the pull-out restricting unit is moved from the pull-out allowable position to the pull-out restricting position, the advancing / retreating member is moved along the orthogonal direction by the inclined portion. When the pull-out restricting means is moved from the pull-out restricting position to the pull-out allowable position, the advancing / retreating member is smoothly moved to the opposite side of the photosensitive drum along the orthogonal direction by the inclined portion. Can be made.
(12) An opening for pulling out the developing unit may be formed on one end side in the axial direction of the housing. In this case, the drawer restricting means is an open / close member configured to be movable between an open position where the opening is opened and a closed position where the opening is closed, the closed position is the drawer restricting position, and the open position is the drawer. Allowable position.

  According to such a configuration, since the drawing restricting means is an opening / closing member, the number of parts can be reduced as compared with the case where the drawing restricting means and the opening / closing member are provided as separate members.

In addition, since the opening is opened when the opening / closing member is located at the open position, the developing unit can be reliably pulled out of the housing, and when the opening / closing member is located at the closed position, the opening is Since it is closed, it is possible to reliably regulate the undesired drawing of the developing unit to the housing.
(13) Further, an endless belt that contacts each of the plurality of photosensitive drums may be provided. In this case, any one of the plurality of developing units includes a belt cleaner that removes and collects the waste developer from the belt, and the belt cleaner is disposed on the belt in a state where the developing unit is disposed at the advanced position. Is configured to collect the waste developer.

According to such a configuration, the waste developer can be removed and collected from the belt by the belt cleaner in a state where the developing unit is disposed at the advanced position.
(14) Further, the belt cleaner may be provided in a developing unit disposed at one end side in the most parallel direction among the plurality of developing units.

  When the belt cleaner is provided in a developing unit other than the developing unit arranged at one end in the parallel direction among the plurality of developing units, the belt cleaner interferes with the arrangement of other members (for example, photosensitive drums). There is.

On the other hand, in the case where the belt cleaner is provided in the developing unit that is disposed closest to one end in the parallel direction among the plurality of developing units, an efficient arrangement of the belt cleaner can be ensured.
(15) A plurality of drum cleaners may be provided which are provided in one-to-one correspondence with the plurality of photosensitive drums and remove and collect the waste developer from the surface of each photosensitive drum. In this case, in each drum cleaner, the waste developer collected from the surface of the corresponding photosensitive drum in a state where the developing unit is disposed at the advanced position and the developing roller is disposed at the separated position, the corresponding photosensitive drum is used. Through the belt.

  According to such a configuration, the waste developer can be removed and collected from the surface of the corresponding photosensitive drum by a plurality of drum cleaners.

  In addition, the waste developer collected by each of the plurality of drum cleaners is placed on the belt via the corresponding photosensitive drum in a state where the developing unit is disposed at the advanced position and the developing roller is disposed at the separated position. And then removed from the belt and collected by a belt cleaner.

  Therefore, both the waste developer collected from the belt and the waste developer collected from the surface of the photosensitive drum can be collected by the belt cleaner.

  As a result, the number of parts can be reduced and the size of the drum cleaner can be reduced as compared with the case where a storage portion for storing the waste developer is provided in each of the plurality of drum cleaners. As a result, the manufacturing cost and size of the image forming apparatus can be reduced.

  In the image forming apparatus of the present invention, the developing unit can be pulled out along the axial direction of the photosensitive drum with respect to the housing while the developing roller and the photosensitive drum can be reliably moved closer to and away from each other. Can do.

1 is a cross-sectional view showing a color printer as a first embodiment of an image forming apparatus of the present invention, and shows a state in which a developing roller is disposed at a close position. It is AA sectional drawing of the color printer shown in FIG. FIG. 2 is a front view of the color printer (a state in which a front wall of an outer casing is removed) shown in FIG. (A) shows sectional drawing of the drum unit shown in FIG. 1, (b) shows BB sectional drawing of the drum unit shown in (a), (c) shows the left side of the drum unit shown in (a) The figure is shown. FIG. 2 is a front view of the color printer (a state in which a front wall of an outer casing is removed) shown in FIG. 1, showing a state in which a developing roller is disposed at a separation position. FIG. 6 shows a cross-sectional view of the color printer shown in FIG. 5. FIG. 2 is a front view of the color printer (a state in which a front wall of an outer casing is removed) shown in FIG. 1, showing a state in which a developing unit is disposed at a retracted position. Sectional drawing for demonstrating drawer | drawing-out with respect to the main body casing of the developing unit shown in FIG. 1, and mounting | wearing is shown. Sectional drawing for demonstrating the drawer with respect to the main body casing of the drum unit shown in FIG. 1, and mounting | wearing is shown. FIG. 6 is a front view of a color printer (a state in which a front wall of an outer casing is removed) as a second embodiment of the image forming apparatus of the present invention.

1. Overall Configuration of Color Printer As shown in FIG. 1, a color printer 1 as an example of an image forming apparatus is a horizontal type intermediate transfer type color printer.

  The color printer 1 is a multifunction device that is integrally provided with a main body casing 2 as an example of a housing and a flat bed scanner 3 that is provided on the upper side of the main body casing 2 and reads image information of a document.

In the main body casing 2, the color printer 1 includes a paper feeding unit 4 for feeding paper P and an image forming unit 5 for forming an image on the fed paper P.
(1) Main Body Casing As shown in FIGS. 1 and 2, the main body casing 2 is formed in a substantially box shape that accommodates the paper feeding unit 4 and the image forming unit 5. As shown in FIG. 2, an opening 8 is formed in one side wall of the main body casing 2, and the front cover 6 as an example of the drawing restricting means and the opening / closing member has the opening 8 as a fulcrum. 2 is slidable (movable) between a closed position (an example of a drawer restricting position, see FIG. 2) and an open position that opens the opening 8 (see an example of a pull-out allowable position, see FIG. 8). .

  In the following description, the side on which the front cover 6 is provided (the left side in FIG. 2) is the front side, and the opposite side (the right side in FIG. 2) is the rear side. In addition, when the color printer 1 is viewed from the front side, the left and right reference is used.

That is, in FIG. 1, the left side of the drawing is the left side, and the right side of the drawing is the right side. Further, the front side of the page is the front side, and the back side of the page is the rear side.
(2) Paper Feed Unit The paper feed unit 4 includes a paper feed tray 7 for storing paper P as shown in FIG. The paper feed tray 7 is detachably attached to the bottom of the main casing 2.

The paper P stored in the paper feed tray 7 is sent between the paper feed roller 10 and the paper feed pad 11 by the rotation of the pickup roller 9, and is fed one by one by the rotation of the paper feed roller 10. Thereafter, the sheet P is fed toward the upper registration rollers 13 so as to sequentially pass between the sheet feeding roller 10 and each pinch roller 12 by the rotation of the sheet feeding roller 10. With the rotation of the registration roller 13, the image is supplied to the image forming unit 5 (between an intermediate transfer belt 38 (described later) and a secondary transfer roller 35 (described later)) at a predetermined timing.
(3) Image Forming Unit The image forming unit 5 is disposed on the upper side of the paper feeding unit 4 and includes a scanner unit 17, a process unit 14, a transfer unit 18, and a fixing unit 19.
(3-1) Scanner Unit The scanner unit 17 is disposed on the upper side of the paper feed tray 7. The scanner unit 17 emits a laser beam to each of a plurality (four) of photosensitive drums 21 (described later) based on the image data (see the solid line in FIG. 1), and exposes the photosensitive drum 21 (described later). To do.
(3-2) Process Unit The process unit 14 is disposed on the upper side of the scanner unit 17 and includes a drum unit 15 and a developing unit 16.
(3-2-1) Drum Unit The drum unit 15 is disposed at the upper end of the process unit 14, and integrally includes a photosensitive drum 21, a scorotron charger 22, and a drum cleaning roller 23 as an example of a drum cleaner. I support it.

  A plurality (four) of photosensitive drums 21 are provided corresponding to each of a plurality of colors (black, yellow, magenta, cyan), and are arranged in parallel in the left-right direction with a space therebetween.

  The scorotron charger 22 is provided in correspondence with each of a plurality (four) of the photosensitive drums 21 and is arranged to face the photosensitive drum 21 with a gap on the lower right side of the corresponding photosensitive drum 21.

The drum cleaning roller 23 is provided in a one-to-one correspondence with each of the plurality (four) of the photosensitive drums 21 so as to be in contact with the photosensitive drum 21 on the right side of the corresponding photosensitive drum 21. Is arranged.
(3-2-2) Developing Unit A plurality (four) of developing units 16 are provided corresponding to each of the plurality (four) of photosensitive drums 21. Further, as will be described in detail later, the developing unit 16 is arranged in a front-rear direction between a developing attachment position (see FIG. 2) attached to the main casing 2 and a developing extraction position (see FIG. 8) drawn from the main casing 2. It is slidable along.

  Each of the plurality (four) of the developing units 16 is arranged on the lower left side of the corresponding photosensitive drum 21 in the state where the developing unit 16 is arranged at the developing attachment position, and is arranged in parallel at intervals in the left-right direction. . More specifically, a black developing unit 16K, a yellow developing unit 16Y, a magenta developing unit 16M, and a cyan developing unit 16C are sequentially arranged from the left side to the right side.

  Each of the plurality (four) of the developing units 16 includes a unit frame 25 and a developing device 24, which will be described in detail later.

  The developing device 24 is accommodated in the unit frame 25 and includes a developing roller 26.

  The developing roller 26 is rotatably supported at the upper end of the developing unit 24 so as to be exposed from the upper side and the right side, and is in contact with the corresponding photosensitive drum 21 from the lower left side. In other words, a plurality (four) of the developing rollers 26 are provided in a one-to-one correspondence with each of the plurality (four) of the photosensitive drums 21.

The developing device 24 includes a supply roller 27 that supplies toner to the developing roller 26 and a layer thickness regulating blade 28 that regulates the thickness of the toner supplied to the developing roller 26. Further, the developing device 24 includes a toner storage unit 29 that stores toner as an example of a developer corresponding to each color (black, yellow, magenta, cyan) below the supply roller 27.
(3-3) Transfer Unit The transfer unit 18 is disposed above the process unit 14 and includes a belt unit 34 and a secondary transfer roller 35.

  The belt unit 34 is disposed along the left-right direction so as to face each of the plurality (four) of the photosensitive drums 21 from above.

  The belt unit 34 includes a driving roller 36, a driven roller 37, an intermediate transfer belt 38 as an example of an endless belt, and a plurality (four) of primary transfer rollers 39.

  The driving roller 36 and the driven roller 37 are disposed to face each other with a space therebetween in the left-right direction.

  The intermediate transfer belt 38 is disposed on the upper side of the photosensitive drum 21 such that the lower portion thereof is in contact with each of the plurality (four) of the photosensitive drums 21, and is suspended around the driving roller 36 and the driven roller 37. Has been. In addition, the intermediate transfer belt 38 is rotated in such a way that the lower portion in contact with the photosensitive drum 21 moves from the left side to the right side by the driving of the driving roller 36 and the driven roller 37.

  Each of the plural (four) primary transfer rollers 39 is provided to face the corresponding photosensitive drum 21 with the lower portion of the intermediate transfer belt 38 interposed therebetween.

The secondary transfer roller 35 is provided on the right side of the belt unit 34 so as to face the driving roller 36 with the intermediate transfer belt 38 interposed therebetween.
(3-4) Fixing Unit The fixing unit 19 is provided on the upper left side of the secondary transfer roller 35 and includes a heating roller 41 and a pressure roller 42 that is pressed against the heating roller 41 from the upper right side. .
(3-5) Image Forming Operation (3-5-1) Developing Operation The toner in the toner container 29 is supplied to the supply roller 27 and further supplied to the developing roller 26.

  The toner supplied to the developing roller 26 is regulated by the layer thickness regulating blade 28 as the developing roller 26 rotates, and is carried on the surface of the developing roller 26 as a thin layer having a constant thickness.

  On the other hand, the surface of the photosensitive drum 21 is uniformly positively charged by the scorotron charger 22 as the photosensitive drum 21 rotates, and then exposed by the scanner unit 17. As a result, an electrostatic latent image corresponding to the image to be formed on the paper P is formed on the surface of the photosensitive drum 21.

When the photosensitive drum 21 further rotates, the toner carried on the surface of the developing roller 26 is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 21. As a result, the electrostatic latent image on the photosensitive drum 21 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 21.
(3-5-2) Transfer / Fixing Operation The toner image carried on the surface of the photosensitive drum 21 is primarily transferred sequentially to the lower portion of the intermediate transfer belt 38 that is moved from the left side to the right side. As a result, a color image is formed on the intermediate transfer belt 38. At this time, toner (waste toner) that has not been transferred to the intermediate transfer belt 38 may remain on the surface of the photosensitive drum 21. The waste toner faces the drum cleaning roller 23 as the photosensitive drum 21 rotates. Then, the waste toner is removed from the surface of the photosensitive drum 21 by the drum cleaning bias, and is electrostatically held (collected) on the peripheral surface of the drum cleaning roller 23.

  The color image formed on the intermediate transfer belt 38 is secondarily transferred onto the paper P supplied from the paper supply unit 4 while the intermediate transfer belt 38 passes through a position facing the secondary transfer roller 35.

The color image transferred onto the paper P is heat-fixed on the paper P in the fixing unit 19 by being heated and pressed while the paper P passes between the heating roller 41 and the pressure roller 42. Is done.
(4) Paper Discharge The paper P on which the toner image has been fixed in the fixing unit 19 is discharged by a paper discharge roller 44 onto a paper discharge tray 45 formed on the upper surface of the main casing 2.
(5) Flatbed Scanner The flatbed scanner 3 is provided above the paper discharge tray 45. The flatbed scanner 3 can read the image information of the original, and the image forming unit 5 can form an image on the paper P as described above based on the read image information of the original.
2. Details of Main Body Casing As shown in FIG. 2, the main body casing 2 includes an outer casing 50 that constitutes the outer shape of the color printer 1, and an inner casing 51 provided inside the outer casing 50.

  The outer casing 50 is formed in a substantially box shape having a substantially rectangular shape when viewed from the side. The opening 8 is formed on the front wall of the outer casing 50 and the front cover 6 is provided.

  The inner casing 51 is formed in a substantially box shape having a substantially rectangular shape when viewed from the side, and has a vertical length and a horizontal length that can accommodate the paper feeding unit 4 and the image forming unit 5 (see FIG. 1). It is accommodated in the outer casing 50 so as to be packed in the front side so as to be spaced from the outer casing 50 on the side.

  Further, the inner space of the inner casing 51 is partitioned by a partition wall 52.

  The partition wall 52 is formed in a substantially flat plate shape extending in the front-rear direction, and the scanner in the vertical direction so as to partition the internal space of the inner casing 51 into an upper unit storage space 53 and a lower scanner tray storage space 54. It is provided between the unit 17 and the developing unit 16 (see FIG. 1).

  The partition wall 52 is formed with an exposure hole (not shown).

  As shown in FIG. 1, the exposure holes (not shown) have a plurality (four) corresponding to laser beams emitted from the scanner unit 17 toward a plurality (four) of photosensitive drums 21 (described later). ) And formed so as to allow the laser beam to pass therethrough.

  Further, the partition wall 52 is integrally provided with a spring fixing portion 55.

  As shown in FIG. 2, the spring fixing portion 55 is formed in a substantially rectangular shape in a side view that protrudes upward from the rear end portion on the upper surface of the partition wall 52 and extends in the left-right direction.

  A moving member 60 as an example of a moving unit is disposed on the upper surface of the partition wall 52.

  As shown in FIGS. 1 and 2, a plurality (four) of moving members 60 are provided corresponding to each of the plurality (four) of developing units 16.

  As shown in FIG. 2, each of the plurality (four) of moving members 60 includes a slide member 61 and an advance / retreat member 62 disposed on the upper side of the slide member 61.

  As shown in FIG. 1, the slide member 61 is formed in a substantially flat plate shape (see FIG. 2) extending in the front-rear direction, and the length in the left-right direction is substantially the same as the length in the left-right direction of the unit frame 25. ing.

  The slide member 61 is integrally provided with a cam portion 63 as an example of a protrusion.

  As shown in FIGS. 1 and 2, a plurality of (four) cam portions 63 are provided corresponding to each end portion (four corners in a bottom view) of a unit bottom wall 70 (described later) of the unit frame 25. . Specifically, each of the plurality of (four) cam portions 63 is provided at the left and right end portions (four corners in plan view) of the front and rear end portions on the upper surface of the slide member 61.

  Further, as shown in FIG. 2, the cam portion 63 is formed in a substantially rectangular shape in side view protruding from the upper surface of the slide member 61 toward the upper side (the advance / retreat member 62 side) along the vertical direction.

  Further, the rear end portion of the cam portion 63 is formed as a first inclined portion 66 as an example of an inclined portion.

  The first inclined portion 66 is formed to be inclined upward as it goes forward.

  The slide member 61 is disposed on the upper surface of the partition wall 52 so that the rear end thereof faces the front surface of the spring fixing portion 55 with a space in the front-rear direction.

  A compression spring 64 is interposed between the rear end portion of the slide member 61 and the front surface of the spring fixing portion 55 as shown in FIG.

  The compression spring 64 is formed in an air-core coil shape extending in the front-rear direction, and a front end portion thereof is fixed to the rear end surface of the slide member 61 and a rear end portion thereof is fixed to the front surface of the spring fixing portion 55.

  Thereby, the slide member 61 is always urged forward by the compression spring 64, and the front end portion of the slide member 61 is opened from the main body casing 2 in a state where the front cover 6 is in the open position. 8 is disposed at a projecting position projecting outside through 8.

  In addition, as shown in FIG. 2, the slide member 61 receives the urging force of the compression spring 64 when the front end portion of the slide member 61 contacts the rear surface of the front cover 6 in a state where the front cover 6 is in the closed position. In contrast, the main body casing 2 is disposed at a storage position in which it is stored. That is, the slide member 61 is provided to be slidable in the front-rear direction along the upper surface of the partition wall 52 between the protruding position and the storage position.

  As shown in FIG. 1, the advancing / retracting member 62 is formed in a substantially U-shape in front view that opens upward and a substantially tray shape (see FIG. 2) that extends in the front-rear direction, and the upper and front sides are open. .

  The upper surface of the advancing / retracting member 62 is formed along the outer shape of the lower end portion of the unit frame 25, and the inner dimension (the length in the left-right direction and the length in the front-rear direction) is the outer dimension (the length in the left-right direction and the length in the left-right direction). The length is approximately the same as the length in the front-rear direction).

  Further, as shown in FIG. 2, a cam groove 65 as an example of a groove portion is formed on the lower surface of the advance / retreat member 62.

  A plurality of (four) cam grooves 65 are formed corresponding to each of the plurality of (four) cam portions 63. Specifically, the cam grooves 65 are formed at the left and right ends (four corners in the bottom view) of the front and rear ends on the lower surface of the advance / retreat member 62.

  The cam groove 65 is formed in a substantially rectangular shape in side view that is recessed upward from the lower surface of the advance / retreat member 62.

  The rear end edge of the cam groove 65 is formed as a second inclined portion 67 as an example of an inclined portion.

  The second inclined portion 67 is formed to be inclined upward as it goes forward.

Then, as shown in FIG. 8, the advance / retreat member 62 is arranged at a fitting position where the cam groove 65 is fitted to the cam portion 63 in a state where the slide member 61 is arranged at the protruding position, as shown in FIG. In addition, in a state where the slide member 61 is disposed at the accommodation position, the lower surface of the advance / retreat member 62 on the rear side of the cam groove 65 abuts on the upper surface of the cam portion 63, and the fitting is moved upward from the fitting position. Arranged in the release position. That is, as shown in FIGS. 2 and 8, the advance / retreat member 62 is provided so as to be able to advance / retreat (move) along the vertical direction between the fitting position and the fitting release position.
3. Details of Developing Unit In a state where the developing unit 16 is disposed at the developing mounting position, the developing unit 16 is disposed above the advancing / retracting member 62 and supported by the advancing / retreating member 62 as shown in FIG. That is, the moving member 60 is arranged on the opposite side of the photosensitive drum 21 with respect to the developing unit 16.

  Therefore, as will be described in detail later, the developing unit 16 is moved in the vertical direction as the advancement / retraction member 62 advances and retracts between the engagement position and the engagement release position.

Further, the developing unit 16 includes the unit frame 25 and the developing device 24 as described above.
(1) Unit Frame As shown in FIGS. 1 and 2, the unit frame 25 is formed in a substantially L shape in front view extending in the front-rear direction. As shown in FIG. 2, the unit frame 25 includes a unit front wall 68 and a unit rear wall 69 that close both front and rear ends, and a unit bottom wall 70 that is laid between the lower ends of the unit frame. .

  In the first embodiment, the configurations related to the unit front wall 68 and the unit rear wall 69 are the same. Therefore, in the following description, the unit front wall 68 will be described in detail, and description of the unit rear wall 69 will be omitted.

  As shown in FIG. 3, the unit front wall 68 is formed in a substantially flat plate shape having a substantially rectangular shape when viewed from the front. A guide hole 71 is formed in the unit front wall 68.

  Two guide holes 71 are formed penetratingly at intervals in the vertical direction corresponding to each of a large-diameter boss 81 (described later) and a small-diameter boss 82 (described later) of the developing device 24. The guide hole 71 is formed in a substantially elliptical shape when viewed from the front, and is formed so as to extend along a facing direction X (described later) between the photosensitive drum 21 and the developing roller 26. The guide hole 71 has a major axis that is approximately 1.5 times as long as the outer diameter of the corresponding large-diameter boss 81 (described later) or small-diameter boss 82 (described later). The outer diameter of the large-diameter boss 81 (described later) or the small-diameter boss 82 (described later) is substantially the same.

  As shown in FIGS. 1 and 2, the unit bottom wall 70 is formed in a substantially flat plate shape extending in the front-rear direction. Further, as shown in FIG. 1, a spring support portion 72 is integrally provided on the unit bottom wall 70.

  The spring support portion 72 is formed in a substantially triangular shape in front view protruding upward from the left end portion on the upper surface of the unit bottom wall 70.

  Further, the unit frame 25 in the black developing unit 16K is integrally provided with a belt cleaner 30 as shown in FIG. That is, the belt cleaner 30 is provided in the developing unit 16 arranged on the leftmost side among the plural (four) developing units 16.

  The belt cleaner 30 is provided on the left side of the unit frame 25 and includes a waste toner container 56, a belt cleaning roller 57, a relay roller 58, and a scraping blade 59.

  The waste toner container 56 is formed in a substantially box shape extending in the vertical direction, and its upper end is opened. The vertical length of the waste toner container 56 is formed longer than the vertical length of the unit frame 25.

  The waste toner container 56 is connected to the left end of the unit frame 25 at the lower portion of the right wall.

  The belt cleaning roller 57 is disposed at the upper end portion in the waste toner storage portion 56 so as to be exposed from the upper side. The belt cleaning roller 57 is formed in a substantially cylindrical shape extending in the front-rear direction, and both front and rear ends thereof are rotatably supported by the waste toner storage unit 56.

  Further, the belt cleaning roller 57 has a lower side of the driven roller 37 so as to face the vertical direction with the driven roller 37 and the intermediate transfer belt 38 interposed therebetween in a state where the black developing unit 16K is disposed at the advanced position (described later). Is arranged.

  The relay roller 58 is disposed below the belt cleaning roller 57 so as to contact the belt cleaning roller 57 from below. The relay roller 58 is formed in a substantially cylindrical shape extending in the front-rear direction, and both front and rear ends thereof are rotatably supported by the waste toner storage unit 56.

The scraping blade 59 is formed in a substantially rectangular shape when viewed from the side in the left-right direction, and is disposed below the relay roller 58 so that the right end thereof is in contact with the lower end of the relay roller 58.
(2) Developer As shown in FIG. 2, the developer 24 is accommodated in the unit frame 25.

  The developing device 24 includes a developing frame 75.

  The developing frame 75 is formed in a hollow cylindrical shape extending in the front-rear direction and opened on the upper side and the right side (see FIG. 1), and both front and rear end portions thereof are closed by the developing front wall 76 and the developing rear wall 77, respectively. Has been.

  In the first embodiment, the configurations relating to the development front wall 76 and the development rear wall 77 are the same. Therefore, in the following description, the development front wall 76 will be described in detail, and the description of the development rear wall 77 will be omitted.

  As shown in FIG. 3, a contacted portion 80 as an example of a working portion and a guided portion 79 are provided on the front surface of the development front wall 76.

  The contacted portion 80 is provided at the upper end of the front surface of the development front wall 76, and is formed in a substantially cylindrical shape that projects forward (outward in the front-rear direction) from the development front wall 76 (see FIG. 2). .

  The guided portion 79 is provided on the lower left side of the abutted portion 80 and includes a large-diameter boss 81 and a small-diameter boss 82.

  The large-diameter boss 81 is provided at a substantially central portion in the vertical direction of the left side portion on the front surface of the development front wall 76, and is formed in a substantially cylindrical shape protruding forward from the development front wall 76 (see FIG. 2).

  The small-diameter boss 82 is disposed on the lower side of the large-diameter boss 81 at a distance from the large-diameter boss 81 in the vertical direction, and is formed in a substantially cylindrical shape protruding forward from the development front wall 76 (see FIG. 2).

  Further, the developing front wall 76 and the developing rear wall 77 support the developing roller 26 so that the developing roller 26 can be rotated so as to be exposed from the upper right side between the upper ends thereof, and as shown in FIG. The toner accommodating portion 29 described above is supported.

  As shown in FIG. 2, the developing unit 24 has a large-diameter boss 81 and a small-diameter boss 82 inserted through the corresponding guide holes 71 from the inside, and as shown in FIG. The end portion is accommodated in the unit frame 25 so as to face the right surface of the spring support portion 72.

  A coil spring 73 is interposed between the lower left end portion of the toner storage portion 29 and the right surface of the spring support portion 72. The coil spring 73 is formed in the shape of an air-core coil, and its right end is at the lower left of the toner container 29 so that its axial direction is substantially parallel to a facing direction X (described later) between the photosensitive drum 21 and the developing roller 26. It is fixed to the end portion, and its left end portion is fixed to the right surface of the spring support portion 72.

  As a result, the developing device 24 is always urged toward the upper right by the coil spring 73.

Therefore, as shown in FIG. 3, the developing device 24 is always disposed at a developing position where the large-diameter boss 81 and the small-diameter boss 82 are located at the upper end portions of the corresponding guide holes 71.
4). Details of the Drum Unit As shown in FIG. 1, the drum unit 15 is disposed above the plurality (four) of the developing units 16, and as shown in FIGS. 4A to 4C, an example of a drum support member. As a drum drawer 85.

  As will be described in detail later, the drum drawer 85 slides in the front-rear direction between a drum mounting position (see FIG. 2) mounted on the main casing 2 and a drum pulling position (see FIG. 9) pulled out from the main casing 2. It is provided as possible.

  As shown in FIG. 4B, the drum drawer 85 includes a pair of drum side walls 86 that are opposed to each other with an interval in the front-rear direction.

  As shown in FIG. 4A, the drum side wall 86 is formed in a substantially flat plate shape that is long in the left-right direction, and a unit groove 87 is formed in the lower portion thereof.

  As shown in FIG. 1, the unit groove 87 overlaps with the upper end portion (upper portion of the developing device 24) of the developing unit 16 in a state where the unit groove 87 is disposed at the advanced position (described later) when projected in the front-rear direction. Notched and formed.

  Specifically, as shown in FIG. 4A, the unit groove 87 corresponding to the black developing unit 16K extends from the center in the vertical direction at the left end edge of the drum side wall 86 toward the right and then to the right. It is cut and formed so as to incline downward as it goes.

  Unit grooves 87 corresponding to the other developing units 16YMC (yellow developing unit 16Y, magenta developing unit 16M, and cyan developing unit 16C) are formed in a substantially U shape that is recessed upward from the lower end edge of the drum side wall 86. Has been.

  The drum side wall 86 is provided with a cam member support portion 88 as shown in FIG.

  A plurality of (three) cam member support portions 88 are arranged in series in the left-right direction at a substantially central portion in the up-down direction on the outer side surface in the front-rear direction of the drum side wall 86. In the first embodiment, three cam member support portions 88 are provided. However, the number and arrangement of the cam member support portions 88 are not limited as long as the cam member 90 (described later) can be supported.

  As shown in FIG. 4B, the cam member support portion 88 is formed in a substantially U shape in a side view, and each free end portion is fixed to the outer side surface in the front-rear direction of the drum side wall 86 (FIG. 3). reference). Further, the inner dimension (vertical length) of the cam member support portion 88 is formed to be substantially the same as the vertical length of the cam member 90 (described later).

  Further, as shown in FIG. 4C, the pair of drum side walls 86 includes a cam member 90 as an example of a contact / separation member, a rotation shaft 91, and a pinion gear 92.

  Two cam members 90 are provided corresponding to each of the pair of drum side walls 86. Further, as shown in FIG. 3, the cam member 90 is formed in a substantially bowl shape that is long in the left-right direction.

  The cam member 90 is provided with a rack gear 93 and a contact portion 94 as an example of an action portion.

  The rack gear 93 is formed on the upper surface of the left end portion of the cam member 90.

  A plurality (four) of the contact portions 94 are provided in the left-right direction so as to correspond to each of the contacted portions 80 of the plurality (four) of the developing devices 24. The contact portion 94 is formed in a substantially rectangular shape in front view protruding downward from the lower end portion of the cam member 90, and is formed so that the left end portion thereof is inclined downward as it goes rightward.

  The cam member 90 is disposed on each of the pair of drum side walls 86 on the outer side in the front-rear direction, and is inserted into each of the plural (three) cam member support portions 88 in the left-right direction. It is supported by.

  That is, as shown in FIG. 2, the cam member 90 is provided at each of the front and rear end portions of the drum drawer 85 and is disposed on the outer side in the front-rear direction than the front development wall 76 and the rear development wall 77 of the development unit 16. Yes.

  Further, the cam member 90 has a first position where the left end portion of the cam member 90 and the left end portion of the drum side wall 86 are substantially aligned when viewed from the front-rear direction, and as shown in FIG. Is provided at a second position protruding leftward from the left end portion of the drum side wall 86 so as to be slidable along the left-right direction. That is, the cam member 90 is configured to be movable relative to the drum side wall 86 (main body casing 2) along the left-right direction.

  As shown in FIG. 4C, the rotation shaft 91 is formed in a substantially cylindrical shape extending in the front-rear direction, and the length in the front-rear direction is longer than the facing interval between the pair of drum side walls 86.

  As shown in FIG. 3, the rotation shaft 91 is installed between the upper portions of the left end portions of the pair of drum side walls 86 (see FIG. 4C). Further, as shown in FIG. 4C, the rotary shaft 91 has each drum side wall such that both front and rear end portions protrude outward in the front-rear direction from the pair of drum side walls 86, respectively. 86 is supported so as to be relatively rotatable.

  The pinion gear 92 is formed in a substantially cylindrical shape extending in the front-rear direction, and gear teeth are formed on the circumferential surface of the pinion gear 92 over the entire circumference.

  As shown in FIG. 3, the pinion gear 92 is relative to the front-rear direction end portion (the portion protruding outward from the drum side wall 86 in the front-rear direction) of the rotating shaft 91 so that the lower portion thereof meshes with the rack gear 93. It is supported so that it cannot rotate. Accordingly, the front and rear pinion gears 92 are provided so as to be integrally rotatable with respect to the drum side wall 86 via the rotation shaft 91.

  Further, between the pair of drum side walls 86, as shown in FIG. 4A, a plurality of (four) photosensitive drums 21, a scorotron charger 22, and a drum cleaning roller 23 are integrally supported. ing.

  As shown in FIG. 4B, the photosensitive drum 21 is formed in a substantially cylindrical shape extending in the front-rear direction, and both front and rear end portions are supported on the drum side wall 86 so as to be relatively rotatable.

That is, the cam member 90 is disposed so as to overlap with a plurality (four) of the photosensitive drums 21 when projected in the front-rear direction.
5. Next, printing and cleaning operations in the color printer 1 will be described.

The color printer 1 can be switched between a color mode for forming a color image (see FIG. 3) and a cleaning mode for collecting waste toner (see FIG. 5).
(1) Printing Operation in Color Mode The color printer 1 can print a color image on the paper P in the state set in the color mode.

  In order to set the color mode in the color printer 1, first, as shown in FIG. 2, the front cover 6 is disposed in the closed position.

  At this time, the front end portion of the slide member 61 is in contact with the rear surface of the front cover 6, and the slide member 61 is disposed at the accommodation position against the urging force of the compression spring 64.

  Thereby, the advance / retreat member 62 is arranged at the fitting release position, and the developing unit 16 is arranged at the advanced position. That is, in the state where the front cover 6 is disposed at the closed position, the fitting between the cam portion 63 of the slide member 61 and the cam groove 65 of the advance / retreat member 62 is released.

  Next, as shown in FIG. 3, each of the pair of cam members 90 is disposed at the first position.

  In order to move the cam member 90 to the first position and the second position (see FIG. 5), a driving force from a driving source (not shown) such as a motor provided in the main body casing 2 is applied to the pinion gear 92. To enter.

  Then, the front and rear pinion gears 92 are integrally rotated. As a result, each of the pair of cam members 90 is integrally moved to the first position and the second position (see FIG. 5) in conjunction with each other.

  In a state in which the cam member 90 is disposed at the first position, the contact portion 94 is disposed on the right side of the corresponding contacted portion 80 so as to face the contacted portion 80 with a space in the left-right direction. . That is, in the state where the cam member 90 is disposed at the first position, the contact (action) between the contact portion 94 of the cam member 90 and the contacted portion 80 of the developing device 24 is released.

  Therefore, as shown in FIG. 1, the developing device 24 is urged toward the upper right by the coil spring 73 and is disposed at the developing position.

  At this time, the developing roller 26 of the developing unit 24 is disposed at a close position that approaches or contacts the corresponding photosensitive drum 21. That is, in the state where the cam member 90 is disposed at the first position, the developing roller 26 is disposed at the close position.

  In the first embodiment, the developing roller 26 is in contact with the corresponding photosensitive drum 21 in the facing direction X in a state where the developing roller 26 is located at the close position.

  Thereby, the color printer 1 is set to the color mode.

  Next, when image data transmitted from an external personal computer or the like is received, the above-described image forming operation is started.

  During the image forming operation, the color image formed on the intermediate transfer belt 38 is secondarily transferred to the paper P as described above.

  At this time, after the color image is secondarily transferred to the paper P, residual transfer toner (waste toner) remains on the intermediate transfer belt 38. When the waste toner faces the belt cleaning roller 57 due to the circumferential movement of the intermediate transfer belt 38, the waste toner is electrostatically held on the peripheral surface of the belt cleaning roller 57 by the belt cleaning bias. As a result, the waste toner is collected on the peripheral surface of the belt cleaning roller 57 from the intermediate transfer belt 38, and the waste toner is removed from the intermediate transfer belt 38.

  Thereafter, when the waste toner carried on the peripheral surface of the belt cleaning roller 57 faces the relay roller 58 as the belt cleaning roller 57 rotates, the waste toner is transferred from the peripheral surface of the belt cleaning roller 57 to the periphery of the relay roller 58. It is electrostatically transferred to the surface.

  When the relay roller 58 rotates, the waste toner on the peripheral surface of the relay roller 58 is scraped off by the scraping blade 59 and falls into the waste toner container 56 due to gravity.

  As a result, waste toner from above the intermediate transfer belt 38 is accommodated in the waste toner accommodating portion 56.

That is, the belt cleaning roller 57 of the belt cleaner 30 is configured to collect waste toner from the intermediate transfer belt 38 in a state where the developing unit 16 is disposed at the advanced position.
(2) Cleaning operation in the cleaning mode The color printer 1 is changed from the color mode to the cleaning mode when the above-described image forming operation is completed.

  Then, as shown in FIG. 6, the driving force is input to the cam member 90 via the pinion gear 92, and the cam member 90 is moved to the left from the first position toward the second position.

  At this time, the abutting portion 94 of the cam member 90 abuts (acts) on the abutted portion 80 of the developing device 24 from the right side. Is pressed toward.

  Then, the developing device 24 is moved toward the lower left along the facing direction X (see FIG. 1) by each of the large-diameter boss 81 and the small-diameter boss 82 being guided by the corresponding guide hole 71. The

  Thus, the developing device 24 is disposed at the non-developing position from the developing position against the urging force of the coil spring 73.

  At this time, the developing roller 26 is disposed at a separated position away from the corresponding photosensitive drum 21.

  That is, the contact portion 94 of the cam member 90 guides the developing roller 26 to move toward the separated position when the cam member 90 is moved from the first position toward the second position, and the cam member 90 In the state where 90 is arranged at the second position, it acts on the contacted portion 80 so that the developing roller 26 is arranged at the separated position.

  Therefore, the cam member 90 acts on the developing device 24 via the contact portion 94 and the contacted portion 80 by the movement of the developing unit 16 in the state where the developing unit 16 is disposed at the advanced position, and moves the developing roller 26 to the close position. And move to the separated position. In other words, the developing roller 26 is configured to be movable between a proximity position and a separation position in a state where the development unit 16 is disposed at the advanced position.

  Next, the waste toner held on the drum cleaning roller 23 is discharged to the peripheral surface of the photosensitive drum 21 as shown in FIG.

  The waste toner discharged to the peripheral surface of the photosensitive drum 21 is opposed to the intermediate transfer belt 38 as the photosensitive drum 21 rotates.

  Then, the waste toner on the surface of the photosensitive drum 21 is transferred to the surface of the intermediate transfer belt 38 by the transfer bias of the primary transfer roller 39.

  In other words, the drum cleaning roller 23 causes the waste toner collected from the surface of the photosensitive drum 21 to pass through the photosensitive drum 21 in a state where the developing unit 16 is disposed at the advanced position and the developing roller 26 is disposed at the separated position. Then, it is conveyed onto the intermediate transfer belt 38.

  Thereafter, the waste toner transferred to the surface of the intermediate transfer belt 38 faces the belt cleaning roller 57 as the intermediate transfer belt 38 rotates.

  Then, as described above, the waste toner is electrostatically held on the peripheral surface of the belt cleaning roller 57, transferred to the relay roller 58 electrostatically, and then scraped off by the scraping blade 59 to store the waste toner. It is dropped into the part 56.

  As a result, the waste toner collected by the drum cleaning roller 23 from the surface of the photosensitive drum 21 is also collected in the waste toner container 56 of the belt cleaner 30.

Thus, the cleaning operation in the cleaning mode is completed.
6). Next, the operation of pulling out and attaching the developing unit 16 to the main casing 2 will be described.
(1) Pulling-out operation of developing unit with respect to main body casing To pull out the developing unit 16 from the main body casing 2 (unit accommodation space 53), first, as shown in FIG. 8, the front cover 6 is moved from the closed position (see FIG. 2). The opening 8 is opened by moving to the open position. As a result, the drawer of the developing unit 16 with respect to the main casing 2 is allowed.

  If it does so, contact | abutting with the front-end part of the slide member 61 and the rear surface of the front cover 6 will be cancelled | released, and the slide member 61 will move ahead toward a protrusion position from an accommodation position (refer FIG. 2).

  As a result, the advance / retreat member 62 is released from the engagement by the cam portion 63 of the slide member 61 being fitted into the cam groove 65 of the advance / retreat member 62 as shown in FIG. It moves downward from the position (see FIG. 2) and is placed at the fitting position.

  As a result, the developing unit 16 is moved (retracted) downward from the advanced position (see FIG. 1) with the movement of the advance / retreat member 62, and is disposed at the retracted position.

  That is, the advance / retreat member 62 moves the developing unit 16 from the advanced position to the retracted position by the sliding movement of the slide member 61 accompanying the movement of the front cover 6 from the closed position to the open position.

  In other words, the moving member 60 moves the developing unit 16 from the advanced position to the retracted position as the front cover 6 moves from the closed position to the open position.

  In the state where the developing unit 16 is disposed at the retracted position, the abutting portion 94 of the cam member 90 and the abutted portion 80 of the developing device 24 are disposed so as to be separated from each other, and the developing unit 16 ( The action on the developing device 24) is released.

  Further, all the developing units 16 are arranged so as not to overlap the cam member 90 when projected in the front-rear direction in the state where they are arranged at the retracted position. In FIG. 7, the cam member 90 is disposed at the second position. On the other hand, in the state where the developing unit 16 is disposed at the retracted position, even if the cam member 90 is disposed at the first position, all the developing units 16 overlap with the cam member 90 when projected in the front-rear direction. It is arranged not to become.

  At this time, the developing roller 26 is opposed to the lower left side of the photosensitive drum 21 with an interval in the facing direction X so as to be separated from the corresponding photosensitive drum 21.

  Specifically, the distance between the developing roller 26 and the corresponding photosensitive drum 21 in the state in which the developing unit 16 is disposed at the retracted position (the length in the facing direction X) is the development in the state in which the developing roller 26 is disposed in the separated position. The distance between the roller 26 and the corresponding photosensitive drum 21 (the length in the facing direction X, see FIG. 5) is longer.

  Further, the belt cleaning roller 57 of the black developing unit 16K is disposed below the driven roller 37 so as to face the intermediate transfer belt 38 with an interval in the vertical direction.

  Next, as illustrated in FIG. 8, the developing unit 16 is pulled out to the front side along the front-rear direction through the opening 8 with respect to the main body casing 2. That is, the developing unit 16 is configured to be able to be pulled out from the developing attachment position (see FIG. 2) attached to the main casing 2 toward the front side in the front-rear direction.

  At this time, the upper end portion of the developing device 24 of the developing unit 16 passes through the corresponding unit groove 87.

  As described above, the developing unit 16 is disposed at the developing drawing position where the developing unit 16 is pulled out from the main body casing 2, and the drawing of the developing unit 16 from the main body casing 2 is completed.

Then, the developing unit 16 is detached from the main casing 2 by pulling the developing unit 16 further forward.
(2) Mounting operation of developing unit with respect to main body casing In order to mount the developing unit 16 with respect to the main body casing 2, an operation is performed in the reverse order of the above-described drawing operation.

  Specifically, first, as shown in FIG. 8, the front cover 6 is disposed at the open position, and the opening 8 is opened.

  At this time, the slide member 61 is disposed at the protruding position, and the advance / retreat member 62 is disposed at the fitting position.

  Next, the developing unit 16 is inserted through the opening 8 as shown in FIG. 8 so that the lower end of the developing unit 16 is inserted into the corresponding advance / retreat member 62 from the front side as shown in FIG. It inserts from the front side with respect to the main body casing 2 (unit accommodation space 53).

  When the developing unit 16 is moved rearward, the lower end of the developing unit 16 is moved rearward along the front-rear direction by being guided by the advancing / retracting member 62 and accommodated in the inner casing 51 ( Installed).

  As a result, the developing unit 16 is disposed at the developing mounting position where the developing unit 16 is mounted in the main casing 2 (unit accommodating space 53) (see FIG. 2).

  Next, as shown in FIG. 2, the front cover 6 is moved from the open position toward the closed position.

  Then, the front end portion of the slide member 61 is brought into contact with the rear surface of the front cover 6, so that the slide member 61 moves rearward from the protruding position toward the accommodation position against the urging force of the compression spring 64. Is done.

  As a result, the advance / retreat member 62 releases the fitting between the cam portion 63 of the slide member 61 and the cam groove 65 of the advance / retreat member 62 as the slide member 61 moves from the protruding position (see FIG. 8) to the accommodation position. By doing so, it is pressed upward by the cam part 63 and moved from the fitting position (see FIG. 8) to the fitting release position.

  Since the developing unit 16 is accommodated in the advance / retreat member 62, the development unit 16 is advanced upward from the retracted position toward the corresponding photosensitive drum 21 and moved to the advance position as the advance / retreat member 62 moves.

  That is, the advance / retreat member 62 moves the developing unit 16 from the retracted position to the advanced position by the sliding movement of the slide member 61 accompanying the movement of the front cover 6 from the open position to the closed position.

  In other words, the moving member 60 moves the developing unit 16 from the retracted position to the advanced position as the front cover 6 moves from the open position to the closed position.

  At this time, as shown in FIG. 3, when the cam member 90 is disposed at the first position, when the developing unit 16 is disposed at the advanced position, the belt cleaning roller 57 of the black developing unit 16K is moved to the intermediate transfer belt 38. The developing roller 26 is disposed at a close position where it contacts the corresponding photosensitive drum 21 from the lower left side.

  On the other hand, as shown in FIG. 5, when the cam member 90 is disposed at the second position, the belt cleaning roller 57 of the black developing unit 16K is moved to the intermediate transfer belt 38 when the developing unit 16 is disposed at the advanced position. While being contacted from the lower side, the contacted portion 80 is contacted from the lower left side to the left end portion of the corresponding contact portion 94, and the developing roller 26 is disposed at a separated position away from the corresponding photosensitive drum 21. The

  Thus, the front cover 6 is disposed at the closed position, and the mounting of the developing unit 16 to the main casing 2 (unit accommodating space 53) is completed.

Further, since the opening 8 is closed in a state where the front cover 6 is disposed at the closed position, the drawer of the developing unit 16 with respect to the main casing 2 is restricted.
7). Next, the operation of pulling out and attaching the drum unit 15 to the main body casing 2 will be described.
(1) Pulling-out operation of drum unit with respect to main body casing To pull out the drum unit 15 from the main body casing 2 (unit housing space 53), first, as shown in FIGS. 2 and 9, the front cover 6 is moved from the closed position to the open position. It is moved to open the opening 8.

  Then, as shown in FIG. 9, the contact between the front end portion of the slide member 61 and the rear surface of the front cover 6 is eliminated, and the slide member 61 is moved from the storage position to the protruding position.

  As the slide member 61 moves, the advance / retreat member 62 is moved from the fitting release position to the fitting position, and as the advance / retreat member 62 moves, the developing unit 16 moves downward from the advanced position. It is moved and placed at the retracted position.

  Thereby, as shown in FIG. 7, the developing roller 26 and the corresponding photosensitive drum 21 are separated from each other.

  Next, as shown in FIG. 9, the drum unit 15 (drum drawer 85) is pulled out to the front side along the front-rear direction through the opening 8 with respect to the main body casing 2. That is, the drum drawer 85 is configured to be able to be pulled out from the drum mounting position (see FIG. 2) mounted on the main body casing 2 toward the front side in the front-rear direction.

  As described above, the drum drawer 85 is disposed at the drum drawing position where the drum drawer 85 is drawn out from the main body casing 2, and the drawing out of the drum unit 15 from the main body casing 2 is completed.

The drum unit 15 is detached from the main casing 2 by pulling the drum drawer 85 further forward.
(2) Drum unit mounting operation with respect to main body casing In order to mount the drum unit 15 with respect to the main body casing 2, an operation is performed in the reverse order of the above-described drawing operation.

  Specifically, first, as shown in FIG. 9, the front cover 6 is disposed at the open position, and the opening 8 is opened.

  At this time, the slide member 61 is disposed at the protruding position, and the advance / retreat member 62 is disposed at the fitting position. Thereby, the developing unit 16 is disposed at the retracted position.

  Next, the drum unit 15 is inserted from the front side into the main body casing 2 (unit accommodation space 53) through the opening 8.

  At this time, since the developing unit 16 is disposed at the retracted position, as shown in FIG. 7, the lower left portion of the photosensitive drum 21 of the drum unit 15 and the upper right portion of the developing roller 26 are spaced in the facing direction X. Are arranged opposite to each other.

  When the drum unit 15 (drum drawer 85) is further moved rearward, the drum drawer 85 is accommodated (mounted) in the inner casing 51.

  As described above, the drum drawer 85 is disposed at the drum mounting position where the drum drawer 85 is mounted in the inner casing 51. That is, the drum drawer 85 is configured to be attached to the main body casing 2.

  Next, as shown in FIG. 2, the front cover 6 is moved from the open position toward the closed position.

  Then, the slide member 61 is moved from the protruding position to the accommodation position against the urging force of the compression spring 64.

  As a result, the advance / retreat member 62 is moved from the fitting position to the fitting release position as the slide member 61 moves from the protruding position to the accommodation position.

  Then, the developing unit 16 is moved from the retracted position to the advanced position as shown in FIGS.

Thus, the mounting of the drum unit 15 to the main casing 2 (unit accommodation space) is completed.
8). Operation and Effect (1) In the color printer 1, as shown in FIG. 2, each of the pair of cam members 90 is disposed outside in the front-rear direction of the drum unit 15 (photosensitive drum 21) (outside in the axial direction of the photosensitive drum 21). In addition, as shown in FIG. 7, they are arranged so as to overlap with a plurality (four) of the photosensitive drums 21 when projected in the front-rear direction (axial direction of the photosensitive drum 21).

  Therefore, an efficient arrangement of the cam member 90 can be ensured and, as shown in FIG. 8, the developing unit 16 is mounted on the main casing 2 (developing mounting position) from the front side (photosensitive drum 21) along the front-rear direction. It is possible to prevent the developing unit 16 and the cam member 90 from interfering with each other when being drawn out toward one side in the axial direction.

  As a result, by moving the cam member 90, the developing roller 26 can be moved to a close position (see FIG. 3) and a separated position (see FIG. 5), and the developing unit 16 can be moved as shown in FIG. The main body casing 2 can be configured to be drawable along the front-rear direction.

In other words, the developing unit 16 can be configured to be drawable in the front-rear direction with respect to the main body casing 2 while the developing roller 26 and the photosensitive drum 21 can be reliably brought close to and separated from each other.
(2) Further, as shown in FIG. 2, the color printer 1 includes a drum drawer 85 that integrally supports a plurality (four) of the photosensitive drums 21. In addition, each of the pair of cam members 90 is provided on the front-rear direction outer side surface of the pair of drum side walls 86 of the drum drawer 85, that is, on both front and rear end portions (both end portions in the axial direction of the photosensitive drum 21) of the drum drawer 85. .

  Therefore, as shown in FIG. 7, the cam member 90 can be disposed so as to be surely overlapped with a plurality (four) of the photosensitive drums 21 when projected in the front-rear direction.

As a result, as shown in FIG. 8, when the developing unit 16 is pulled out from the developing attachment position in the front-rear direction toward the front side, the developing unit 16 and the cam member 90 can be reliably prevented from interfering with each other.
(3) As shown in FIG. 9, the drum drawer 85 is configured to be able to be pulled out from the state (drum mounting position) mounted on the main body casing 2 toward the front side in the front-rear direction.

  Therefore, a plurality of (four) photosensitive drums 21 are integrally supported by a drum drawer 85 as shown in FIG. 4A, and the drum drawer 85 can be pulled out from the main casing 2 as shown in FIG. Since it is configured, a plurality (four) of the photosensitive drums 21 can be exchanged at the same time.

As a result, compared with the case where each of the plurality (four) of photosensitive drums 21 is replaced separately, the replacement work of the plurality (four) of photosensitive drums 21 can be made more efficient. Maintenance can be improved.
(4) Further, as shown in FIGS. 3 and 5, the cam member 90 has a first position (see FIG. 3) where the developing roller 26 is disposed in the close position and a second position where the developing roller 26 is disposed in the separated position. The contact portion 94 is configured to be slidable to a position (see FIG. 5) and guides the developing roller 26 to move toward the separated position when the position is moved from the first position to the second position. ing.

  Further, as shown in FIG. 5, the developing device 24 of the developing unit 16 abuts (acts) on the abutting portion 94 when the cam member 90 is disposed at the second position, as shown in FIG. A contacted portion 80 is provided in which the contact (action) is released from the contact portion 94 when the cam member 90 is disposed at the first position.

  Therefore, in the state where the cam member 90 is disposed at the second position, as shown in FIG. 5, the contact portion 94 is in contact with the contacted portion 80, and the cam member 90 is disposed at the first position. As shown in FIG. 3, the action of the contact portion 94 on the contacted portion 80 is released.

  As a result, the sliding movement of the cam member 90 can be reliably applied to the developing device 24 of the developing unit 16 via the contact portion 94 and the contacted portion 80.

Accordingly, the sliding movement of the cam member 90 can reliably move the developing roller 26 between the proximity position and the separation position.
(5) Further, the color printer 1 includes a moving member 60 as shown in FIG.

  3 and 5, the moving member 60 advances the developing unit 16 toward the corresponding photosensitive drum 21, and advances so that the developing roller 26 can move between the proximity position and the separation position. As shown in FIG. 7, the developing roller 26 is moved from the advanced position to the retracted position so as to be separated from the corresponding photosensitive drum 21 rather than the state where the developing roller 26 is disposed at the separated position.

  Further, the moving member 60 is disposed on the opposite side of the developing unit 16 from the photosensitive drum 21.

  Therefore, as shown in FIGS. 3 and 5, the developing unit 16 is arranged at the advanced position so that the developing roller 26 can be moved between the proximity position and the separation position. If the developing unit 16 is arranged at the advanced position, the developing roller 26 and the photosensitive drum 21 can be brought close to and separated from each other.

  Further, as shown in FIG. 7, the developing unit 16 is disposed so as to be retracted from the corresponding photosensitive drum 21 rather than the advanced position in the state where it is disposed at the retracted position. Compared with the state of being placed at the advanced position (see FIG. 5), the door is retracted. Therefore, as shown in FIG. 8, when the developing unit 16 is pulled out from the main body casing 2 along the front-rear direction, the developing unit 16 and the cam member 90 can be reliably prevented from interfering with each other.

  In the state where the developing unit 16 is disposed at the retracted position, as shown in FIG. 7, the developing roller 26 is disposed so as to be separated from the corresponding photosensitive drum 21 as compared to the state disposed at the separated position. . Therefore, as shown in FIG. 8, when the developing unit 16 is pulled out from the main casing 2, it is possible to prevent the developing roller 26 and the photosensitive drum 21 from contacting and sliding.

  Further, since the moving member 60 is disposed on the side opposite to the photosensitive drum 21 with respect to the developing unit 16, the developing unit 16 can be smoothly moved to the advanced position and the retracted position.

  Therefore, by arranging the developing unit 16 at the advanced position, the developing roller 26 and the photosensitive drum 21 can be reliably brought close to and separated from each other (see FIGS. 3 and 5). Further, by disposing the developing unit 16 in the retracted position, as shown in FIG. 8, it is possible to reliably suppress the interference between the developing unit 16 and the cam member 90 when the developing unit 16 is pulled out from the main casing 2. Further, sliding of the developing roller 26 and the photosensitive drum 21 can be suppressed (see FIG. 7).

Further, when the developing unit 16 is pulled out from the main casing 2, it is possible to prevent the moving member 60 from obstructing the pulling out of the developing unit 16. Therefore, the developing unit 16 can be smoothly pulled out from the main casing 2.
(6) Further, as shown in FIG. 7, each of the plurality (four) of the developing units 16 is projected in the front-rear direction (axial direction of the photosensitive drum 21) in the state of being disposed at the retracted position. The cam member 90 is arranged so as not to overlap.

Therefore, if each of the plural (four) developing units 16 is disposed at the retracted position, the developing unit 16 and the cam member 90 interfere when the developing unit 16 is pulled out from the main casing 2 along the front-rear direction. Can be suppressed more reliably.
(7) Further, as shown in FIGS. 3 and 5, the cam member 90 is configured to act on the developing unit 16 by the movement of the cam member 90 in a state where the developing unit 16 is disposed at the advanced position. In addition, when the developing unit 16 is disposed at the retracted position, the action on the developing unit 16 is released.

  Specifically, in the state where the developing unit 16 is disposed at the advanced position, as shown in FIG. 5, when the cam member 90 is disposed at the second position, the contact portion 94 contacts the corresponding contacted portion 80. When the cam member 90 is disposed at the first position as shown in FIG. 3, the contact (action) between the contact portion 94 and the corresponding contacted portion 80 is released.

  Therefore, the movement of the cam member 90 is reliably acted on the developing roller 26 via the developing unit 16. As a result, the developing roller 26 can be reliably moved to the proximity position and the separation position.

On the other hand, in the state where the developing unit 16 is disposed at the retracted position, as shown in FIG. 7, even if the cam member 90 is disposed at the second position, the contacted portion 80 corresponding to the contact portion 94 is obtained. Is released. That is, in a state where the developing unit 16 is disposed at the retracted position, the cam member 90 and the developing unit 16 are separated so that the contact (action) between the contact portion 94 and the contacted portion 80 is released. Therefore, when the developing unit 16 is pulled out from the main casing 2, it is possible to more reliably prevent the developing unit 16 and the cam member 90 from interfering with each other.
(8) The color printer 1 includes a front cover 6 as shown in FIG.

  The front cover 6 is configured to be movable between a closed position for restricting the drawer of the developing unit 16 from the main casing 2 and an open position for allowing the drawer of the developing unit 16 to the main casing 2 as shown in FIG. Yes.

  Therefore, it is possible to allow the developing unit 16 to be pulled out from the main body casing 2 in a state where the front cover 6 is disposed in the open position, and as shown in FIG. 2, a desired state is obtained in a state where the front cover 6 is disposed in the closed position. The drawing of the developing unit 16 to the main casing 2 can be restricted.

  Further, as shown in FIGS. 2 and 8, the moving member 60 moves the developing unit 16 to the advanced position as the front cover 6 moves to the closed position (see FIG. 2) and the open position (see FIG. 8). (See FIG. 3) and the retracted position (see FIG. 7). That is, since the developing unit 16 and the front cover 6 are interlocked, as shown in FIG. 8, if the user places the front cover 6 in the open position in order to pull out the developing unit 16 from the main body casing 2, FIG. As shown, the developing unit 16 is disposed at the retracted position.

  Therefore, it is possible to improve the efficiency of the operation of moving the developing unit 16 from the advanced position to the retracted position, compared to the case where the front cover 6 and the developing unit 16 are moved independently. Further, by disposing the front cover 6 in the open position in order to pull out the developing unit 16 from the main casing 2, the developing unit 16 can be reliably disposed in the retracted position.

Accordingly, while the efficiency of the drawing operation of the developing unit 16 with respect to the main casing 2 can be improved, it is possible to reliably suppress the interference between the developing unit 16 and the cam member 90, and the developing roller 26 and the photosensitive drum 21 are slid. It can also be suppressed.
(9) Further, as shown in FIG. 2, the moving member 60 is slidable along the front-rear direction (the axial direction of the photosensitive drum 21) as the front cover 6 moves between the closed position and the opened position. The configured slide member 61 and the developing unit 16 are supported, and the slide member 61 is slid to move in the vertical direction (the orthogonal direction perpendicular to both the axial direction of the photosensitive drum 21 and the parallel direction of the plurality of photosensitive drums 21). And an advancing and retracting member 62 configured to be movable along.

  Further, as shown in FIG. 8, the advancing / retracting member 62 moves the developing unit 16 from the advanced position to the retracted position by the sliding movement of the slide member 61 accompanying the movement of the front cover 6 from the closed position to the open position ( As shown in FIG. 2, the developing unit 16 is moved from the retracted position to the advanced position by the sliding movement of the slide member 61 accompanying the movement of the front cover 6 from the open position to the closed position (FIG. 3). reference).

  That is, the slide member 61 is slid along with the movement of the front cover 6, and the advance / retreat member 62 moves the developing unit 16 between the advanced position and the retracted position by the slide movement of the slide member 61.

Therefore, the movement of the front cover 6 and the movement of the developing unit 16 can be reliably interlocked via the slide member 61 and the advance / retreat member 62.
(10) Further, as shown in FIG. 2, the slide member 61 is provided with a cam portion 63 that protrudes toward the upper side (the advance / retreat member 62 side) along the vertical direction. On the other hand, the advance / retreat member 62 is formed with a cam groove 65 corresponding to the cam portion 63.

  In the state where the front cover 6 is disposed in the open position, as shown in FIG. 8, the cam portion 63 and the cam groove 65 are fitted, and in the state where the front cover 6 is disposed in the closed position, FIG. As shown in FIG. 5, the fitting between the cam portion 63 and the cam groove 65 is released.

  Therefore, in the state where the front cover 6 is disposed at the closed position, the cam portion 63 is released from the fitting with the cam groove 65, so that the cam portion 63 contacts the lower surface of the advance / retreat member 62.

  As a result, the advancing / retracting member 62 is advanced upward corresponding to the protruding amount of the cam portion 63 so that the developing unit 16 is disposed at the advanced position, and is disposed at the mating release position.

  On the other hand, in the state where the front cover 6 is disposed at the open position, the cam portion 63 is fitted into the cam groove 65 as shown in FIG.

  Therefore, the advancing / retreating member 62 is disposed at the fitting position where it is retracted downward so that the developing unit 16 is disposed at the retracted position.

That is, the advance / retreat member 62 can be reliably moved along the vertical direction to the engagement release position (see FIG. 2) and the engagement position, and the developing unit 16 is reliably moved to the retracted position and the advance position. be able to.
(11) Further, as shown in FIG. 8, the cam portion 63 is formed with a first inclined portion 66, and the cam groove 65 is formed with a second inclined portion 67.

  Each of the first inclined portion 66 and the second inclined portion 67 moves upward (from the upstream side in the drawing direction of the developing unit 16 toward the downstream side in the drawing direction) from the rear end thereof, upward (in the vertical direction, the photosensitive drum 21). Side).

Therefore, as shown in FIG. 2, when the front cover 6 is moved from the open position (see FIG. 8) to the closed position, the first inclined portion 66 and the second inclined portion 67 have a simple configuration. The advance / retreat member 62 can be smoothly moved upward from the fitting position (see FIG. 8) toward the fitting release position.
(12) Further, as shown in FIG. 2, an opening 8 for drawing out the developing unit 16 is formed in the front wall of the outer casing 50 of the main casing 2 (one axial end of the main casing 2). .

  Further, the front cover 6 is configured to be movable between an open position for opening the opening 8 (see FIG. 8) and a closed position for closing the opening 8 (see FIG. 2).

  Therefore, the number of parts can be reduced as compared with the case where the drawer restricting means and the front cover 6 are provided as separate members.

Further, in the state where the front cover 6 is disposed at the open position, as shown in FIG. 8, the opening 8 is opened, so that the drawer of the developing unit 16 with respect to the main body casing 2 can be reliably permitted. In the state of being disposed at the closed position, as shown in FIG. 2, the opening 8 is closed, so that undesired withdrawal of the developing unit 16 from the main casing 2 can be reliably regulated.
(13) Further, as shown in FIG. 1, the color printer 1 includes an intermediate transfer belt 38 that is in contact with each of a plurality (four) of the photosensitive drums 21.

  Of the plurality (four) of developing units 16, the black developing unit 16K includes a belt cleaner 30 that removes and collects waste toner from the intermediate transfer belt 38, and the belt cleaner 30 is illustrated in FIGS. As shown, the waste toner is collected from the intermediate transfer belt 38 in a state where the developing unit 16 is disposed at the advanced position.

Therefore, the waste toner can be removed from the intermediate transfer belt 38 and collected by the belt cleaner 30 in a state where the developing unit 16 is disposed at the advanced position.
(14) Further, the belt cleaner 30 is provided in the black developing unit 16K disposed on the leftmost side (one end side in the parallel direction of the photosensitive drum 21) among the plurality (four) of the developing units 16. Therefore, an efficient arrangement of the belt cleaner 30 can be ensured.
(15) The drum drawer 85 is provided in one-to-one correspondence with the plurality (four) of the photosensitive drums 21, and a plurality (four) of removing and collecting waste toner from the surface of each photosensitive drum 21. The drum cleaning roller 23 is integrally supported.

  Therefore, the waste toner can be removed and collected from the surface of the corresponding photosensitive drum 21 by the plural (four) drum cleaning rollers 23.

  As shown in FIG. 5, each drum cleaning roller 23 is collected from the surface of the corresponding photosensitive drum 21 in a state where the developing unit 16 is disposed at the advanced position and the developing roller 26 is disposed at the separated position. The used waste toner is conveyed onto the intermediate transfer belt 38 via the corresponding photosensitive drum 21.

  As a result, the waste toner collected by each of the plural (four) drum cleaning rollers 23 is conveyed onto the intermediate transfer belt 38 via the corresponding photosensitive drum 21 and then transferred to the intermediate transfer belt 38 by the belt cleaner 30. It is removed from the belt 38 and collected.

  As a result, the waste toner collected from the intermediate transfer belt 38 and the waste toner collected from the surface of the photosensitive drum 21 can both be collected by the belt cleaner 30.

Therefore, the number of parts can be reduced as compared with the case where each of the plurality (four) of drum cleaning rollers 23 is provided with a storage unit for storing waste toner. As a result, the manufacturing cost of the color printer 1 can be reduced. Can be reduced and downsized.
9. Second Embodiment Next, a second embodiment of the present invention will be described.

  FIG. 10 shows a front view of a color printer (with the front wall of the outer casing removed) as a second embodiment of the image forming apparatus of the present invention.

  10, parts corresponding to those shown in FIGS. 1 to 9 are given the same reference numerals as those, and their explanation is omitted.

  In the first embodiment, as shown in FIGS. 3 and 5, the color mode and the cleaning mode can be switched. In the second embodiment, the color mode and the monochrome mode for forming a black image are provided. It is configured to be switchable.

  In this case, the cam member 90 is not provided with the contact portion 94 corresponding to the contacted portion 80 of the developing device 24 in the black developing unit 16K.

  Therefore, in a state where the plurality (four) of the developing units 16 are arranged at the advanced position and the cam member 90 is arranged at the second position, the developing roller 26 of the black developing unit 16K has the abutted portion 80. Since the developing device 24 is disposed at the developing position without being in contact with the contact portion 94, it is disposed at the close position. On the other hand, each of the developing rollers 26 of the other developing units 16YMC is disposed at a separated position because the abutted portion 80 is abutted against the abutting portion 94 and the developing device 24 is disposed at the non-developing position.

  That is, in the second embodiment, the cam member 90 is disposed at the second position in a state where the plurality (four) of the developing units 16 are disposed at the advanced position, whereby the plurality (four) of the developing rollers 26 are disposed. Among these, it is possible to set the monochrome mode in which only the developing roller 26 of the black developing unit 16K is disposed at a close position where the developing roller 26 faces and contacts the corresponding photosensitive drum 21.

  Therefore, in the second embodiment, the color mode and the monochrome mode are achieved by moving the cam member 90 to the first position and the second position in a state where the plurality (four) of the developing units 16 are arranged at the advanced position. And can be switched as appropriate.

  Therefore, in the second embodiment, a color image can be formed on the paper P by setting the color mode, and a monochrome (black) image can be formed on the paper P by setting the monochrome mode.

Also by this, the same effect as the first embodiment described above can be achieved.
10. In the first and second embodiments described above, as shown in FIG. 1, the developing roller 26 is in contact with the corresponding photosensitive drum 21 in a state where the developing roller 26 is located at the close position.

  On the other hand, the developing roller 26 may be configured to form a slight gap in which the toner can fly with the corresponding photosensitive drum 21 in a state where the developing roller 26 is positioned in the proximity position.

  Even in this case, the toner can be supplied to the corresponding photosensitive drum 21 in a state where the developing roller 26 is located at the close position, and from the corresponding photosensitive drum 21 in a state where the developing roller 26 is located in the separated position. Ensure separation.

  Therefore, during image formation, while the toner can be reliably supplied to the photosensitive drum 21, the developing roller 26 and the photosensitive drum 21 interfere with each other when the developing unit 16 is attached to and detached from the main body casing 2. It can be reliably suppressed.

  In addition, the first embodiment, the second embodiment, and the modifications described above can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 Color printer 2 Main body casing 6 Front cover 8 Opening part 15 Drum unit 16 Developing unit 21 Photosensitive drum 26 Developing roller 30 Belt cleaner 38 Intermediate transfer belt 60 Moving member 61 Slide member 62 Advance / retreat member 63 Cam member 65 Cam groove 66 1st inclination part 67 Second inclined portion 80 Contacted portion 85 Drum drawer 90 Cam member 94 Contacting portion

Claims (15)

A housing,
A plurality of photosensitive drums arranged in parallel and spaced apart from each other;
Each of the plurality of photosensitive drums has a developing roller provided corresponding to the photosensitive drum in a one-to-one correspondence, and is configured to be able to be pulled out from the casing toward the one end side in the axial direction along the axial direction of the photosensitive drum. A plurality of development units;
It is configured to be movable with respect to the housing along a parallel direction of the plurality of photosensitive drums, and by the movement, the developing roller is brought into proximity with a position where the developing roller approaches or contacts the corresponding photosensitive drum, A contact / separation member configured to move to a separation position where the developing roller is separated from the corresponding photosensitive drum,
The contacting / separating member is
An image forming apparatus, wherein the image forming apparatus is disposed on one end side in the axial direction of the photosensitive drum so as to overlap the plurality of photosensitive drums when projected in the axial direction. A drum support member that integrally supports the plurality of photosensitive drums;
The image forming apparatus according to claim 1, wherein the contact / separation member is provided on one end side in the axial direction of the drum support member.   The image forming apparatus according to claim 2, wherein the drum support member is configured to be drawable from the housing along the axial direction toward one end side in the axial direction. The contacting / separating member is
And is configured to be slidable between a first position where the developing roller is disposed at the close position and a second position where the developing roller is disposed at the separated position.
An action unit for guiding the developing roller to move toward the separation position when the developing roller moves from the first position to the second position;
The developing unit is
An actuated portion that is acted on the acting portion in a state where the contact / separation member is disposed at the second position, and that is actuated by the acting portion in a state where the contact / separation member is disposed at the first position. The image forming apparatus according to claim 1, further comprising: an image forming apparatus according to claim 1. The developing unit;
Advancing position where the developing roller is moved toward the corresponding photosensitive drum, and the developing roller is arranged so as to be movable between the proximity position and the separation position;
A moving means configured to move the developing roller to a retreat position for retreating from the advance position so that the developing roller is separated from the corresponding photosensitive drum than the state where the developing roller is disposed at the separation position;
The image forming apparatus according to claim 1, wherein the moving unit is disposed on a side opposite to the photosensitive drum with respect to the developing unit.   6. The image forming apparatus according to claim 5, wherein each of the plurality of developing units does not overlap the contact / separation member when projected in the axial direction in a state where the plurality of developing units are disposed at the retracted position. . The contacting / separating member is
In the state where the developing unit is disposed at the advanced position, the developing unit is configured to act on the developing unit by the movement,
The image forming apparatus according to claim 5, wherein an action on the developing unit is released in a state where the developing unit is disposed at the retracted position. A drawing restricting means configured to be movable between a drawing restricting position for restricting the drawing of the developing unit to the housing and a drawing allowing position for allowing the developing unit to be drawn from the housing;
The moving means is
With the movement of the pull-out restricting means from the pull-out restricting position to the pull-out allowable position, the developing unit is moved from the advanced position to the retracted position,
6. The apparatus according to claim 5, wherein the developing unit is moved from the retracted position to the advanced position in accordance with the movement of the pull-out restricting unit from the pull-out allowable position to the pull-out restricting position. The image forming apparatus according to claim 1. The moving means is
A slide member configured to be slidable along the axial direction in accordance with the movement of the pull-out restricting position and the pull-out allowable position of the pull-out restricting means;
An advancing and retracting member configured to support the developing unit and to be movable along an orthogonal direction perpendicular to both the axial direction and the parallel direction by sliding movement of the slide member;
The advance / retreat member is:
The developing unit is moved from the advanced position to the retracted position by the sliding movement of the slide member in association with the movement of the pulling restricting means from the pulling restricting position to the pulling allowable position.
The developing unit is moved from the retracted position to the advanced position by sliding movement of the slide member accompanying movement of the pull-out restricting unit from the pull-out allowable position to the pull-out restricting position. The image forming apparatus according to 8. One of the slide member and the advance / retreat member is provided with a protrusion that protrudes toward the other side along the orthogonal direction, and on the other side, a groove corresponding to the protrusion is formed,
In the state where the pull-out restricting means is disposed at the pull-out allowable position, the protrusion and the groove are fitted,
10. The image forming apparatus according to claim 9, wherein the fitting between the protrusion and the groove is released in a state where the pull-out restricting unit is disposed at the pull-out restricting position.   At least one of the protrusion and the groove is formed with an inclined portion that is inclined toward the photosensitive drum in the orthogonal direction from the upstream side in the drawing direction of the developing unit toward the downstream side in the drawing direction. The image forming apparatus according to claim 10. An opening for pulling out the developing unit is formed on one end side in the axial direction of the casing,
The drawer regulating means is an opening / closing member configured to be movable between an open position for opening the opening and a closed position for closing the opening,
The image forming apparatus according to claim 8, wherein the closed position is the pull-out restriction position, and the open position is the pull-out allowable position. An endless belt in contact with each of the plurality of photosensitive drums;
Any one of the plurality of development units includes a belt cleaner that removes and collects the waste developer from the belt,
The belt cleaner is configured to collect waste developer from the belt in a state where the developing unit is disposed at the advanced position. The image forming apparatus described in the item.   The image forming apparatus according to claim 13, wherein the belt cleaner is provided in a developing unit disposed closest to one end in the parallel direction among the plurality of developing units. Each of the plurality of photosensitive drums is provided in a one-to-one correspondence, and includes a plurality of drum cleaners that remove and collect waste developer from the surface of each of the photosensitive drums,
Each of the drum cleaners corresponds to the waste developer collected from the surface of the corresponding photosensitive drum in a state where the developing unit is disposed at the advanced position and the developing roller is disposed at the separated position. The image forming apparatus according to claim 13, wherein the image forming apparatus is conveyed onto the belt via the photosensitive drum.

Images