JP3720305B2 - Image forming machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming machine such as a printer, a copying machine, and a facsimile, and more particularly to an image forming machine provided with an intermediate transfer member.
[0002]
[Prior art]
The full-color image forming machine includes an intermediate transfer unit including an intermediate transfer body for sequentially transferring toner images formed on the toner image forming body sequentially with four color toners. The intermediate transfer unit is configured to be attachable to and detachable from the body housing in order to facilitate maintenance and inspection and jam processing. The intermediate transfer unit is positioned at an operating position where the intermediate transfer member is brought into contact with the toner image forming member in a state where the intermediate transfer unit is mounted at a predetermined mounting position. On the other hand, when the intermediate transfer unit is detached from the predetermined mounting position, it is necessary to release the contact state between the intermediate transfer member and the toner image forming member, and the intermediate transfer member is moved to a retracted position for separating the intermediate transfer member from the toner image forming member. After the operation, the intermediate transfer unit is detached from the mounting position.
[0003]
[Problems to be solved by the invention]
Thus, when the intermediate transfer unit is removed from the attachment position without performing the operation of positioning the intermediate transfer member at the retracted position when the intermediate transfer unit is removed from the predetermined attachment position, the intermediate transfer body and the toner image forming body Since the intermediate transfer member moves in the contact state, there is a problem that the toner image forming member is damaged.
[0004]
The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is that the intermediate transfer unit must be positioned at the retracted position when the intermediate transfer unit is detached from the predetermined mounting position. An object of the present invention is to provide an image forming machine configured such that the unit cannot be detached from the mounting position.
[0005]
[Means for Solving the Problems]
In order to solve the above main technical problem, according to the present invention, a toner image forming body rotatably disposed in a machine housing and an intermediate transfer body for transferring a toner image formed on the toner image forming body. In an image forming machine comprising an intermediate transfer unit provided with the intermediate transfer unit configured to be attachable to and detachable from the body housing,
The intermediate transfer unit includes an intermediate transfer body support mechanism that rotatably supports the intermediate transfer body, and the intermediate transfer body is brought into contact with the toner image forming body in a state where the intermediate transfer unit is positioned at a predetermined mounting position. An intermediate transfer body contact / separation mechanism that operates to a retracting position that is separated from the toner image forming body, and a movement direction of the intermediate transfer unit in a state in which the intermediate transfer unit is positioned at a predetermined mounting position. A movement restriction mechanism that regulates
The intermediate transfer member contact / separation mechanism includes an operation lever that can be operated to a separation regulating position that operates the intermediate transfer member to the working position and a separation allowable position that operates the intermediate transfer member to the retracted position.
The movement restricting mechanism operates in conjunction with the intermediate transfer member contact / separation mechanism, and a stopper provided on the side of the machine housing when the intermediate transfer member contact / separation mechanism positions the intermediate transfer member at the working position. A movement restricting member that is positioned at a movement restricting position that is engaged, and is positioned at an allowable movement position that does not engage with the stopper when the intermediate transfer member contact / separation mechanism positions the intermediate transfer member at the retracted position;
The intermediate transfer unit includes an operation lever restriction mechanism that restricts the operation of the operation lever when the operation lever is positioned at the disengagement allowable position, and the operation lever restriction mechanism that restricts the operation of the operation lever. A locking mechanism that locks the operation of the operation lever regulating mechanism. When the intermediate transfer unit is positioned at the mounting position of the fuselage housing, the lock mechanism contacts the actuating member provided on the fuselage housing. Touch to release the lock,
An image forming machine is provided.
[0006]
The intermediate transfer member contacting / separating mechanism is configured such that a stopper pin for selectively restricting the operation of the operation lever can be inserted / removed at an intermediate position between the release restriction position and the release allowance position. In the positioned state, it is desirable that the intermediate transfer member is positioned closer to the retracted position than the operating position and slightly separated from the toner image forming member.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of an image forming machine configured according to the present invention will be described below with reference to the accompanying drawings.
[0008]
FIG. 1 is a schematic sectional view of a color laser beam printer as an image forming machine constructed according to the present invention.
The illustrated color laser beam printer includes a cuboid-shaped machine body housing 2 formed of synthetic resin. A photosensitive drum 3 as a toner image forming body is rotatably disposed in the body housing 2 at a substantially central portion of the body housing 2. The photosensitive drum 3 is driven to rotate by sequentially passing through a charging area, an electrostatic latent image forming area, a developing area, an image transfer area, and a cleaning area in a direction indicated by an arrow by a gear transmission (not shown). Around the photosensitive drum 3, a charging corona discharge device 4 configured in accordance with the present invention in a charging area, a developing device 5 in a developing area, an intermediate transfer body 6 as a toner image forming body in an image transferring area, and a cleaning A cleaning mechanism 7 for the photosensitive drum is provided in each area. Further, a cleaning mechanism 8 for the intermediate transfer member is disposed at the lower left portion of the intermediate transfer member 6 in FIG. In the illustrated embodiment, the developing device 5 includes a yellow toner developing unit 5a, a magenta toner developing unit 5b, a cyan toner developing unit 5c, and a black toner developing unit 5d.
[0009]
A laser unit 9 serving as an electrostatic latent image forming unit is disposed in the upper part of the housing 2. The laser unit 9 projects laser light based on image information output from a computer, for example, onto the peripheral surface of the photosensitive drum 3 in an electrostatic latent image forming area between the charging area and the developing area. In addition, a secondary transfer roller 10 is disposed below the intermediate transfer body 6 in the lower part of the machine housing 2, and on the downstream side (left side in FIG. 1) of the secondary transfer roller 10. A conveyance belt mechanism 11 and a fixing unit 12 are provided.
[0010]
Next, the operation of the laser beam printer described above will be briefly described.
While the photosensitive drum 3 is rotated in the direction indicated by the arrow, the corona discharger 4 for charging charges the photosensitive layer of the photosensitive drum 3 to a specific polarity. Next, laser light is emitted from the laser unit 9 onto the photosensitive drum 3 in the electrostatic latent image forming area between the charging area where the corona discharger 4 for charging is disposed and the developing area where the developing device 5 is disposed. The electrostatic latent image corresponding to the image information is formed on the peripheral surface of the photosensitive drum 3 by being projected. Thereafter, the developing device 5 causes toner to act on the electrostatic latent image on the photosensitive drum 3 to visualize the electrostatic latent image. The toner image formed on the photosensitive drum 3 in this way is transferred to an intermediate transfer member 6 as a toner image forming member. In the case of color printing, for each color, the photosensitive drum 3 is charged by the corona discharger 4 for charging, the exposure by the laser unit 9, the developing unit 5a for yellow toner, the developing unit 5b for magenta toner, and the developing for cyan toner. Development is performed by the unit 5c and the black toner developing unit 5d, and the image is transferred to the intermediate transfer member 6 each time. As a result, a multicolor toner image corresponding to the image signal for one sheet is transferred to the intermediate transfer body 6.
[0011]
On the other hand, the sheet P fed from a sheet feeding device (not shown) is temporarily stopped by a pair of registration rollers (not shown), and the intermediate transfer member 6 is timed with the intermediate transfer member 6 to which the toner image is transferred as described above. And the secondary transfer roller 10 are conveyed to a secondary transfer area facing each other. A toner image formed on the peripheral surface of the intermediate transfer member 6 by the action of the transfer roller 10 is transferred to the surface of the paper P conveyed to the secondary transfer area. The sheet P on which the toner image has been transferred is peeled off from the intermediate transfer member 6 and conveyed to the fixing unit 12 by the conveying belt mechanism 11, where the toner image is heated and fixed on the surface of the sheet and then discharged out of the housing 2. Is done.
[0012]
The residual toner adhering to the surface of the photosensitive drum 3 after the toner image is transferred from the photosensitive drum 3 to the intermediate transfer body 6 as described above is removed by the cleaning mechanism 7. On the other hand, residual toner adhering to the surface of the intermediate transfer body 6 after the toner image is transferred from the intermediate transfer body 6 to the paper P is removed by the cleaning mechanism 8.
[0013]
In the image forming machine described above, the photosensitive drum 3, the corona discharger 4 for charging, the developing device 5 and the cleaning mechanism 7 for the photosensitive drum in the developing area are integrally configured as a process unit. Further, an intermediate transfer body 6 and an intermediate transfer body contact / separation mechanism (to be described later) that contacts or retracts the intermediate transfer body 6 with respect to the photosensitive drum 3 are integrally configured as an intermediate transfer unit. Further, the secondary transfer roller 10 and the transport belt mechanism 11 are also integrally configured as a transfer transport unit. These process unit, intermediate transfer unit, transfer conveyance unit, and fixing unit 12 are configured to be attachable / detachable from the front side along guide members provided in the machine housing 2. FIG. 2 shows a state in which the front cover 2a disposed on the side surface on the front side of the machine housing 2 in the image forming machine is opened, and the process unit 20 and the intermediate transfer unit described above are contained in the machine housing 2. 30, the transfer conveyance unit 21 and the fixing unit 12 are inserted and stored from the front side. FIG. 3 shows a state in which the transfer conveyance unit 21, the fixing unit 12, and the intermediate transfer unit 30 are pulled out from the predetermined mounting position shown in FIG.
[0014]
Hereinafter, the intermediate transfer unit 30 will be described with reference to FIGS.
As shown in FIG. 4, the intermediate transfer unit 30 includes a unit case 31, and the intermediate transfer body 6 is rotatably disposed in the unit case 31. A front cover 32 is attached to the front side (lower left side in FIG. 4) of the unit case 31, and a rear cover 33 is attached to the rear side (upper right side in FIG. 4). FIG. 6 shows a plan view of an intermediate transfer member support mechanism 40 that rotatably supports the intermediate transfer member 6. The rotation shaft 6a of the intermediate transfer member 6 is rotatably supported by bearing levers 42 and 42 on support levers 41 and 41 mounted on the front side plate 311 and the rear side plate 312 of the unit case 31, respectively. Note that intermediate transfer member position regulating members 6b and 6b are attached to the rotary shaft 6a on the inner side of the front side plate 311 and the rear side plate 312 respectively. The intermediate transfer member position regulating member 6b is formed in a fan shape as shown in FIG. The intermediate transfer member 6 is provided with a driven gear 6c at the right end in FIG. 4, and this driven gear 6c is connected to a gear transmission (not shown).
[0015]
Here, the relationship between the front side plate 311 and the rear side plate 312 and the support levers 41 and 41 will be described with reference to FIG. Since the front side plate 311 and the rear side plate 312 and the support levers 41 and 41 have substantially the same configuration, the front side plate 311 and the support lever 41 attached thereto will be described.
One end of the support lever 41 is swingably supported by the front side plate 311 by the support shaft 43, and the rotation shaft 6 a of the intermediate transfer body 6 is rotatably supported via the bearing 42 at the intermediate portion. . Accordingly, when the support lever 41 swings about the support shaft 43, the intermediate transfer member 6 supported by the intermediate portion of the support lever 41 is brought into contact with the photosensitive drum 3, and the operation position shown in FIG. It is actuated to a retracted position separated from 3. In the illustrated embodiment, the support shaft 43 of the support lever 41 is arranged on a line that is substantially perpendicular to the lower side with respect to the line connecting the rotation shaft of the photosensitive drum 3 and the rotation shaft 6 a of the intermediate transfer body 6. It is installed. With this configuration, the separation distance between the photosensitive drum 3 and the intermediate transfer body 6 can be maximized with respect to the swing amount of the support lever 41.
[0016]
As described above, in order to allow movement of the rotation shaft 6a of the intermediate transfer body 6 due to the swing of the support lever 41 around the support shaft 43, the front plate 311 is formed with a long hole 311a. The support lever 41 is provided with a non-guide groove 411 formed around the support shaft 43, and the non-guide groove 411 is supported by being fitted to a guide pin 313 attached to the front side plate 311. The swing of the lever 41 is guided. In addition, a spring locking portion 412 is provided at an intermediate portion of the support lever 41, and a tension coil spring 44 is stretched between the spring locking portion 412 and the spring locking portion 311 b provided on the front side plate 311. It is installed. Accordingly, the support lever 41 is biased to rotate counterclockwise in FIG. 7 about the support shaft 43 by the spring force of the tension coil spring 44. The other end portion of the support lever 41 is provided with an actuated portion 413 on which an intermediate transfer body contact / separation mechanism 50 described later acts.
[0017]
The intermediate transfer unit 30 in the illustrated embodiment is separated from the photosensitive drum 3 and an operation position in which the intermediate transfer body 6 is brought into contact with the photosensitive drum 3 shown in FIG. 7 while being positioned at a predetermined mounting position of the machine housing 2. An intermediate transfer member contacting / separating mechanism 50 that is operated to the retracted position is provided. The intermediate transfer member contact / separation mechanism 50 includes an operation cam 51 having a cam surface 511 that abuts on an actuated portion 413 provided at the other end of the support lever 41. The operation cam 51 is made of an appropriate synthetic resin, and a driven gear 52 is integrally formed. As shown in FIG. 6, the operation cam 51 is attached to an operation shaft 53 that is rotatably supported by the front side plate 311 and the rear side plate 312. A driven gear 52 configured integrally with the operating cam 51 meshes with a driving gear 54 that is rotatably mounted on a support shaft 314 attached to the front side plate 311. The boss 541 of the drive gear 54 is provided with an engagement protrusion 415a protruding in the radial direction. The intermediate transfer member contact / separation mechanism 50 in the illustrated embodiment includes an operation lever 55 that is attached to the front cover 32 and operates the drive gear 54 as shown in FIG. The operation lever 55 includes a connecting portion 551 that fits with the boss 541 of the drive gear 54 at the upper end. The operation lever 55 is disposed on the front side of the concave portion 321 of the front cover 32, and the connecting portion 551 is inserted through a hole (not shown) provided in the wall of the concave portion 321 to fit with the boss 541 of the drive gear 54. As will be described later, they are configured to be operable to a separation regulating position where the intermediate transfer body 6 is operated to the operating position and a separation allowable position where the intermediate transfer body 6 is operated to the retracted position. Note that a movement restricting member 60 is attached to the operating shaft 53 at a position inside the front side plate 311 as shown in FIG. Since the movement restricting member 60 is attached to the operating shaft 53 on which the operating cam 51 is mounted, the movement restricting member 60 is operated in conjunction with the operation of the operating cam 51.
[0018]
8 and 9 show a state in which the front cover 32 is removed and the operation lever 55 is connected to the boss 541 of the drive gear 54 in order to facilitate understanding of the intermediate transfer member contact / separation mechanism 50. FIG. 8 shows a state in which the intermediate transfer unit 30 is positioned at a predetermined mounting position of the machine housing 2 and the intermediate transfer body 6 is positioned at an operating position where the intermediate transfer body 6 contacts the photosensitive drum 3. At this time, the outer peripheral surface of the intermediate transfer member position restricting member 6b attached to the rotation shaft 6a of the intermediate transfer member 6 contacts the stopper roller 20a disposed in the process unit 20. In the state where the intermediate transfer unit 30 shown in FIG. 8 is positioned at a predetermined mounting position of the body housing 2 and the intermediate transfer body 6 is positioned at the working position where the intermediate transfer body 6 contacts the photosensitive drum 3, the operating lever 55 is shown in FIG. The movement restricting member 60 attached to the operating shaft 53 is positioned at a position (a position in contact with a stopper 323 provided on the front cover 32 as shown by a two-dot chain line in FIG. 5). It is positioned at a movement restricting position that engages with a stopper 2e provided on the body housing 2 side. As a result, when the intermediate transfer unit 30 is to be pulled out toward the front side, the movement restricting member 60 engages with the stopper 2e provided on the machine body housing 2 side to restrict the movement. Accordingly, the movement restricting member 60 attached to the operating shaft 53 operates in conjunction with the intermediate transfer member contact / separation mechanism 50, and moves in the separation direction with the intermediate transfer unit 30 positioned at a predetermined mounting position. It functions as a movement restricting mechanism that restricts the movement.
[0019]
In the illustrated embodiment, the operation lever 55 is configured to selectively restrict swinging of the operation lever 55 toward the separation restriction position at an intermediate position indicated by a solid line in FIG. That is, the front cover 32 is provided with a hole (not shown) through which the stopper pin 62 that contacts the operation lever 55 at an intermediate position indicated by a solid line in FIG. Therefore, when the stopper pin 62 is inserted into a hole (not shown) as shown in FIG. 5, the operation lever 55 is restricted from swinging at an intermediate position shown by a solid line in FIG. At this time, the intermediate transfer member 6 is positioned closer to the mounting position than the operating position, and is slightly separated from the photosensitive drum 3. In this state, the movement restricting member 60 is in a position to engage with the stopper 2e. In this way, the stopper pin 62 is inserted into the removable hole and the operation lever 55 is positioned at the intermediate position shown by the solid line in FIG. 5 when the image forming machine is shipped from the factory. As a result, it is possible to eliminate problems caused by the contact between the intermediate transfer member 6 and the photosensitive drum 3 over a long period from when the image forming machine is shipped to the factory until it is actually used. The stopper pin 62 is removed when the image forming machine arrives and is unpacked.
[0020]
As shown in FIG. 8, the intermediate transfer unit 30 is moved from the state where the intermediate transfer unit 30 is positioned at a predetermined mounting position of the body housing 2 and the intermediate transfer body 6 is positioned at the working position where the intermediate transfer body 6 contacts the photosensitive drum 3. When pulling out from the predetermined mounting position 2, first, the operating lever 55 is rotated clockwise around the support shaft 314 as indicated by an arrow in FIG. 8. Accordingly, the drive gear 54 connected to the connecting portion 551 of the operation lever 55 rotates clockwise around the support shaft 314 as indicated by an arrow in FIG. 9 and is engaged with the drive gear 54. As shown by the arrow in FIG. 9, 52 is rotated counterclockwise about the operating shaft 53. As a result, the operating cam 51 configured integrally with the driven gear 52 also rotates counterclockwise about the operating shaft 53 as shown by the arrow in FIG. The support lever 41 provided with the contacted part 413 is rotated clockwise about the support shaft 43 as indicated by an arrow in FIG. When the support lever 41 swings to the position shown in FIG. 9, the intermediate transfer member 6 supported by the support lever 41 is positioned at a retracted position that is separated from the photosensitive drum 3 as shown in FIG. 9. At this time, the intermediate transfer member position restricting member 6b attached to the rotation shaft 6a of the intermediate transfer member 6 is also separated from the stopper roller 20a provided in the process unit 20.
[0021]
In the illustrated embodiment, the direction in which the intermediate transfer member 6 is separated from the photosensitive drum 3 by swinging the support lever 41 is the diagonally lower right direction in FIG. Interference can be avoided and can be accommodated in the fuselage housing 2. That is, if the configuration is such that the intermediate transfer member 6 is spaced downward, it is necessary to take measures to avoid interference with the transfer device such as the transfer roller 10, and if the intermediate transfer member 6 is configured to separate the intermediate transfer member 6 in the lateral direction. The problem arises that the width dimension of the housing 2 increases. However, in the illustrated embodiment, the intermediate transfer member 6 is obliquely separated from the photosensitive drum 3 in the lower right direction, and thus the above problem is solved.
[0022]
As described above, in order to position the intermediate transfer member 6 at the retracted position away from the photosensitive drum 3, first, when the operation lever 55 is operated to the disengagement allowable position shown in FIG. 9, the movement attached to the operation shaft 53 is performed. The restricting member 60 rotates counterclockwise about the operating shaft 53 and is positioned at a movement allowable position where it does not engage with the stopper 2e provided on the machine body housing 2 side. Thus, by positioning the intermediate transfer body 6 at the retracted position, the intermediate transfer unit 30 can be extracted from the machine body housing 2, and the intermediate transfer unit 30 is extracted from the machine body housing 2 while the intermediate transfer body 6 is in the operating position. As a result, damage to the photosensitive drum 3 can be prevented.
[0023]
The intermediate transfer unit 30 in the illustrated embodiment has an operation lever restriction mechanism that restricts the operation of the operation lever 55 in a state where the operation lever 55 with the intermediate transfer member 6 shown in FIG. 70. The operation lever regulating mechanism 70 is disposed on the front cover 32 (see FIG. 5). Hereinafter, the operation lever regulating mechanism 70 will be described with reference to FIGS. 10 and 11.
The operating lever regulating mechanism 70 in the illustrated embodiment includes a lever regulating member 71 whose middle portion is rotatably supported by a support pin 322 provided in the horizontal direction on the front cover 32, and the lever regulating member 71 as a support pin. A compression coil spring 72 is provided to urge around 322 to rotate clockwise in the drawing. The lever restricting member 71 is provided on the left side of the support pin 322 in the drawing and engages with the operation lever 55 in the operation restricting state shown in FIG. 11, and the direction of the support pin 322 from the upper end of the lock surface 711. An operation guide surface 712 inclined downward, a manual operation portion 713 protruding leftward in the drawing from the lower end of the locking surface 711, and a locking mechanism which will be described later and provided to protrude rightward in the drawing from the support pin 322. And an engaging portion 714 to be engaged. The lever restricting member 71 configured as described above is biased by the compression coil spring 72 to rotate clockwise around the support pin 322 in the drawing, and a part of the manual operation portion 713 is shown at a position indicated by a solid line in the drawing. Abuts against a stopper portion 312 provided on the front cover 32, and its rotation is restricted.
[0024]
Next, the operation of the operation lever regulating mechanism 70 will be described.
In FIG. 10, the solid line shows a state in which the intermediate transfer unit 30 is positioned at a predetermined mounting position of the machine body housing 2 and the intermediate transfer body 6 is positioned at the operation position shown in FIG. When the intermediate transfer unit 30 is withdrawn from the predetermined mounting position of the machine body housing 2 from the state where the intermediate transfer body 6 is positioned at the operating position, the operation shaft 55 is moved from the disengagement restricting position indicated by the solid line in FIG. It rotates clockwise as the center. When the operation lever 55 rotates about the support shaft 314 in the clockwise direction in FIG. 10, the lower end of the operation lever 55 rotates while coming into contact with the operation guide surface 712 of the lever restricting member 71 as shown by a two-dot difference line. The member 71 rotates counterclockwise about the support shaft 314 against the spring force of the compression coil spring 72. When the operation lever 55 is further rotated clockwise in FIG. 10 around the support shaft 314, the lower end thereof is disengaged from the operation guide surface 712, so that the lever restricting member 71 causes the support shaft 314 to be moved by the spring force of the compression coil spring 72. 10 rotates clockwise in FIG. 10, and the lower end portion of the operation lever 55 is positioned at the disengagement allowable position on the left side in the drawing from the locking surface 711 as shown in FIG. As a result, the intermediate transfer unit 30 is positioned at the retracted position shown in FIG. 9 as described above, and the stopper in which the movement restricting member 60 attached to the operating shaft 53 is provided on the body housing 2 side as described above. 2e is positioned at a movement allowable position that does not engage with 2e. When the operation lever 55 is positioned at the separation allowance position shown in FIG. 11, the separation restriction for positioning the intermediate transfer body 6 at the operation position in the counterclockwise direction around the support shaft 314 by the locking surface 711 of the lever restriction member 71. Since the rotation in the direction of the position is restricted, the state where the intermediate transfer body 6 is positioned at the retracted position is maintained. In this way, by extracting the intermediate transfer unit 30 from the machine housing 2 with the intermediate transfer body 6 held at the retracted position, the photosensitive drum 3 can be detached without being damaged.
[0025]
The intermediate transfer unit 30 in the illustrated embodiment includes a lever restricting member 71 that restricts the operation of the operation lever 55 at the detachable allowable position shown in FIG. 11 and a lock mechanism 80 that locks the operation in the restricted state. . Hereinafter, the lock mechanism 80 will be described with reference to FIGS. 10 to 13.
In the illustrated embodiment, the lock mechanism 80 includes a lock lever 81 having a support shaft 811 at an intermediate portion. The lock lever 81 is provided with a lock portion 812 that engages with the engagement portion 714 of the operation restricting member 71 at one end portion, and an operation protrusion 813 at the other end portion. The lock lever 81 configured as described above is disposed in a direction in which the support shaft 811 is orthogonal to the support pin 322 of the operation restriction member 71 and is rotatably supported by the front cover 32. In the illustrated embodiment, the lock mechanism 80 is disposed between the operating protrusion 813 of the lock lever 81 and the front cover 32, and rotates the lock lever 81 counterclockwise in FIGS. 12 and 13 about the support shaft 811. A compression coil spring 82 that biases as much as possible is provided. The lock lever 81 rotated by the spring force of the compression coil spring 82 abuts on a stopper surface 715 provided on the engaging portion 714 of the lever regulating member 71 when the lock portion 812 is in the lock position shown in FIG. On the other hand, when the intermediate transfer unit 30 is positioned at a predetermined mounting position of the machine housing 2, the operation protrusion 813 of the lock lever 81 contacts the operation member 2 f provided on the machine housing 2 side, as shown in FIG. It rotates clockwise against the spring force of the compression coil spring 82. As a result, the engagement between the lock portion 812 of the lock lever 81 and the engagement portion 714 of the lever restricting member 71 is released.
[0026]
Next, the operation of the lock mechanism 80 will be described.
When the intermediate transfer unit 30 is positioned at a predetermined mounting position of the machine housing 2, the engagement between the lock portion 812 of the lock lever 81 and the engagement portion 714 of the lever restricting member 71 is released as shown in FIG. Therefore, as shown in FIG. 10, when the manual operation portion 713 of the lever restricting member 71 is pushed downward, the lever restricting member 71 resists the spring force of the compression coil spring 72 as shown by a two-dot chain line. It is rotated counterclockwise about 314. As a result, the engagement state between the lower end of the operation lever 55 and the locking surface 711 of the lever restricting member 71 is released, and the operation lever 55 can be operated to the disengagement restricting position indicated by the solid line in FIG. The transfer body 6 can be positioned at the operating position.
[0027]
When the intermediate transfer unit 30 is extracted from the position where the intermediate housing unit 2 is positioned at the predetermined mounting position, as described above, the operation lever 55 is rotated clockwise from the position shown by the solid line in FIG. Rotate. At this time, since the engagement between the lock portion 812 of the lock lever 81 and the engagement portion 714 of the lever restricting member 71 is released, the operation lever 55 can be positioned at the disengagement allowable position shown in FIG. 11 as described above. it can. As a result, the intermediate transfer unit 30 is positioned at the retracted position as described above, and the movement restricting member 60 attached to the operating shaft 53 is engaged with the stopper 2e provided on the body housing 2 side as described above. It is positioned at the movement allowable position. When the intermediate transfer unit 30 is removed from the machine housing 2 with the intermediate transfer body 6 held at the retracted position, the lock lever 81 is counterclockwise in FIGS. 12 and 13 about the support shaft 811 by the spring force of the compression coil spring 82. 13 and is positioned at the lock position located above the engaging portion 714 of the lever restricting member 71 as shown in FIG. As a result, when the intermediate transfer unit 30 is pulled out from the predetermined mounting position of the machine housing 2, the operation of the lever restricting member 71 is restricted, and the operation lever 55 is positioned at the disengagement allowable position shown in FIG. Since the operation is restricted in the state, the intermediate transfer body 6 is held at the retracted position. Accordingly, the photosensitive drum 3 is not damaged when the intermediate transfer unit 30 is mounted at a predetermined mounting position of the machine housing 2 next time.
[0028]
【The invention's effect】
The image forming apparatus according to the present invention includes a movement restricting mechanism that restricts the movement of the intermediate transfer unit in the detaching direction in a state where the intermediate transfer unit is positioned at a predetermined mounting position. Operates in conjunction with the transfer body contact / separation mechanism. When the intermediate transfer body contact / separation mechanism positions the intermediate transfer body at the operating position, the intermediate transfer body is positioned at a movement restriction position that engages with a stopper provided on the machine housing side. Since the body contact / separation mechanism includes a movement restricting member that is positioned at an allowable movement position that does not engage with the stopper when the intermediate transfer member is positioned at the retracted position, the intermediate transfer unit is mounted on the machine body by positioning the intermediate transfer member at the retracted position. It can be extracted from the housing. Accordingly, it is possible to prevent the photosensitive drum 3 from being damaged by pulling out the intermediate transfer unit from the machine housing while the intermediate transfer member is in the operating position.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a laser beam printer as an image forming machine configured according to the present invention.
FIG. 2 is a perspective view showing a state where a front cover of the image forming machine shown in FIG. 1 is opened.
3 is a perspective view illustrating a state in which an intermediate transfer unit, a transfer conveyance unit, and a fixing unit of the image forming apparatus illustrated in FIG. 1 are pulled out.
4 is a perspective view of an intermediate transfer unit equipped in the image forming machine shown in FIG.
5 is a side view of the intermediate transfer unit shown in FIG.
6 is a plan view showing an intermediate transfer member support mechanism constituting the intermediate transfer unit shown in FIG.
7 is a side view showing a state where an operation lever is removed from an intermediate transfer body contact / separation mechanism constituting the intermediate transfer unit shown in FIG.
8 is a side view showing a state in which an intermediate transfer member in the intermediate transfer member contact / separation mechanism constituting the intermediate transfer unit shown in FIG.
9 is a side view showing a state in which the intermediate transfer member in the intermediate transfer member contacting / separating mechanism constituting the intermediate transfer unit shown in FIG. 4 is positioned at the retracted position.
10 is a side view showing a state of a separation restriction position in an operation lever restriction mechanism provided in the intermediate transfer unit shown in FIG.
FIG. 11 is a side view showing a state of a separation allowable position in an operation lever regulating mechanism provided in the intermediate transfer unit shown in FIG.
12 is a side view showing a locked state in a lock mechanism provided in the intermediate transfer unit shown in FIG.
13 is a side view showing a lock release state in a lock mechanism provided in the intermediate transfer unit shown in FIG. 4. FIG.
[Explanation of symbols]
2: Housing of image forming machine
3: Photosensitive drum
4: Corona discharger for charging
5: Developing device
5a: Development unit for yellow toner
5b: Development unit for magenta
5c: Cyan toner developing unit
5d: Development unit for black toner
6: Intermediate transfer member
7: Cleaning mechanism for photosensitive drum
8: Cleaning mechanism for intermediate transfer member
9: Laser unit
10: Secondary transfer roller
11: Conveyor belt mechanism
12: Fixing unit
20: Process unit
21: Transfer conveyance unit
30: Intermediate transfer unit
31: Unit case
32: Front cover
33: Rear cover
40: Intermediate transfer member support mechanism
41: Support lever
43: Bearing
43: Support shaft
50: Intermediate transfer member contact / separation mechanism
51: Actuating cam
52: Driven gear
53: Actuating shaft
54: Drive gear
55: Operation lever
60: Movement restriction member
70: Control lever regulating mechanism
71: Lever restricting member
72: Compression coil spring
80: Lock mechanism
81: Lock lever
82: Compression coil spring

Claims (2)

A toner image forming body rotatably disposed in a machine body housing and an intermediate transfer unit including an intermediate transfer body for transferring a toner image formed on the toner image forming body, the intermediate transfer unit being a machine body In an image forming machine configured to be detachable from the housing,
The intermediate transfer unit includes an intermediate transfer body support mechanism that rotatably supports the intermediate transfer body, and the intermediate transfer body is brought into contact with the toner image forming body in a state where the intermediate transfer unit is positioned at a predetermined mounting position. An intermediate transfer body contact / separation mechanism that operates to a retracting position that is separated from the toner image forming body, and a movement direction of the intermediate transfer unit in a state in which the intermediate transfer unit is positioned at a predetermined mounting position. A movement restriction mechanism that regulates
The intermediate transfer member contact / separation mechanism includes an operation lever that can be operated to a separation regulating position that operates the intermediate transfer member to the working position and a separation allowable position that operates the intermediate transfer member to the retracted position.
The movement restricting mechanism operates in conjunction with the intermediate transfer member contact / separation mechanism, and a stopper provided on the side of the machine housing when the intermediate transfer member contact / separation mechanism positions the intermediate transfer member at the working position. A movement restricting member that is positioned at a movement restricting position that is engaged, and is positioned at an allowable movement position that does not engage with the stopper when the intermediate transfer member contact / separation mechanism positions the intermediate transfer member at the retracted position ;
The intermediate transfer unit includes an operation lever restriction mechanism that restricts the operation of the operation lever when the operation lever is positioned at the disengagement allowable position, and the operation lever restriction mechanism that restricts the operation of the operation lever. A locking mechanism that locks the operation of the operation lever regulating mechanism. When the intermediate transfer unit is positioned at the mounting position of the fuselage housing, the lock mechanism contacts the actuating member provided on the fuselage housing. Touch to release the lock,
An image forming machine. The intermediate transfer member contact / separation mechanism is configured such that a stopper pin that selectively restricts the operation of the operation lever at an intermediate position between the separation restriction position and the separation permission position is detachable. The image forming apparatus according to claim 1, wherein the intermediate transfer member is positioned closer to the retracted position than the operating position and slightly separated from the toner image forming member in the state of being positioned at the intermediate position.

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