JP5719568B2 - Locking mechanism for replacement unit, replacement unit including the same, and image forming apparatus - Google Patents

Description

  The present invention relates to a lock mechanism for an exchange unit such as a drum unit, which is detachably mounted on an image forming apparatus such as an electrophotographic copying machine or a laser printer, an exchange unit including the same, and an image forming apparatus.

  Conventionally, in an image forming apparatus such as an electrophotographic copying machine or a laser printer, a toner cartridge, a photosensitive drum, a charging device, and a cleaning device that supply toner from a toner supply port to a developing unit of the image forming device are unitized. An exchange unit such as a drum unit and a developing unit that supplies toner to the photosensitive drum is detachably attached to the image forming apparatus main body. In the case of the configuration as described above, a lock mechanism is provided so that the replacement unit is not detached from the apparatus main body except when necessary.

  For example, Patent Document 1 discloses a lock mechanism that releases a lock by converting a force that lifts a lock and handle member into a force that urges a hook shaft portion downward. In Patent Document 2, the rotation axis of a hook that locks a cover that is rotatably supported by the image forming apparatus main body extends in a direction orthogonal to the rotation direction of the cover, and both the rotation direction of the cover and the rotation axis of the hook are provided. A cover opening / closing mechanism is disclosed in which the cover is unlocked by rotating the rotation shaft of the hook by sliding movement of a slider that is slidable in a direction perpendicular to the direction of the cover.

  However, the method of Patent Document 1 requires a structure that converts an upward force that lifts the lock and handle member into a downward force, and the method of Patent Document 2 requires a slider slide mechanism. There was a problem that is complicated.

  On the other hand, as a mechanism for locking the replacement unit and the image forming apparatus main body with a simple configuration, a rotatable L-shaped hook is provided on the replacement unit side, and the tip of the hook is attached when the replacement unit is mounted on the image forming apparatus main body. There is known a lock mechanism that engages with an engagement portion of an image forming apparatus main body. FIG. 6 shows a state where the hook and the apparatus main body are engaged in the conventional lock mechanism. The hook 35 is provided at the distal end of the replacement unit (not shown) in the insertion direction so as to be rotatable in a direction perpendicular to the insertion direction (in the direction of the arrow AA ′), and a biasing member such as a spring (see FIG. (Not shown) is biased in the direction in which the hook tip engages (arrow A direction). When the replacement unit is inserted to a predetermined position, the hook 35 engages with the engaging portion 50 on the image forming apparatus main body side.

JP-A-7-121083 JP 2002-72599 A

  The L-shaped hook 35 as shown in FIG. 6 is provided with a die draft angle θ (indicated by a broken line in the drawing) on the engaging surface 35a in consideration of formability. For this reason, the hook 35 may not be completely engaged, and the replacement unit may be locked imperfectly. Further, when the hook 35 and the engaging portion 50 are engaged, the engaging portion 50 engages while sliding along the draft angle of the engaging surface 35a. Therefore, the replacement unit is inserted into the image forming apparatus main body. There was also a problem that it was difficult to tell whether it was locked or not.

  In view of the above problems, the present invention can lock the replacement unit and the apparatus main body with a simple configuration and can easily check the locked state, the replacement unit including the replacement unit, and the image forming apparatus. The purpose is to provide.

  In order to achieve the above object, the present invention provides a lock mechanism for locking an exchange unit that is detachably attached to an image forming apparatus main body in a state of being attached to the image forming apparatus main body. An L-shaped hook that protrudes in the mounting direction and engages with the engaging portion on the image forming apparatus main body side, and a protrusion that protrudes in the direction opposite to the unit mounting direction at the tip of the locking surface of the hook A locking member that is rotatable in a direction orthogonal to the mounting direction of the replacement unit, and a biasing member that biases the locking member in a direction in which the hook and the engaging portion are engaged. And a release lever that rotates the lock member in a direction to release the engagement between the hook and the engagement portion.

  According to the present invention, in the lock mechanism having the above-described configuration, the release lever also serves as a handle portion of the replacement unit.

  According to the present invention, in the locking mechanism having the above-described configuration, the protrusion is formed only at a substantially central portion in the width direction of the locking surface of the hook.

  Moreover, this invention is an exchange unit provided with the lock mechanism of the said structure.

  The present invention also provides an image forming apparatus on which the replacement unit having the above-described configuration is mounted.

  According to the first configuration of the present invention, the hook and the engaging portion are not engaged unless the replacement unit is inserted to a position exceeding the track drawn by the tip of the projection by forming the projection on the locking surface of the hook. It has become. Therefore, the pushing amount of the replacement unit can be increased, and poor engagement between the hook and the engaging portion can be prevented beforehand. Further, when the replacement unit is inserted to a position exceeding the track drawn by the tip of the protrusion, the hook is vigorously engaged with the engaging portion by the urging force of the urging member. It can be easily confirmed that the hook is completely engaged up to the base of the hook by the engagement sound.

  According to the second configuration of the present invention, in the locking mechanism of the first configuration, the release lever also serves as the handle portion of the replacement unit, so that the unlocking of the replacement unit and the removal of the replacement unit can be performed. It can be performed simultaneously with one operation of pulling the part in the pulling direction.

  Further, according to the third configuration of the present invention, in the locking mechanism of the first or second configuration, the projection is formed only at the substantially center portion in the width direction of the hook locking surface, thereby engaging with the hook. The engagement with the portion can be smoothly released. In addition, it is easy to form a protrusion by providing a die hole in the lock member.

  In addition, according to the fourth configuration of the present invention, since the lock mechanism having any one of the first to third configurations is provided, the attachment / detachment operation with respect to the image forming apparatus main body is easy, and the image forming apparatus main body is securely attached. It becomes an exchange unit that can be locked to.

  According to the fifth configuration of the present invention, an image forming apparatus in which the replacement unit can be easily attached and detached and the replacement unit is securely locked by mounting the replacement unit having the fourth configuration. Become.

1 is a schematic cross-sectional view showing an example of an image forming apparatus on which a drum unit having a lock mechanism of the present invention is mounted. 1 is an external perspective view of a drum unit according to an embodiment of the present invention. FIG. 2 is an enlarged view of the upstream end of the drum unit in the insertion direction. Side view of a locking member used in the locking mechanism of the present invention The enlarged view which shows the engagement state of the hook by the side of a drum unit, and the engaging part by the side of an image forming apparatus main body in the locking mechanism of this invention. The enlarged view which shows the engagement state of the hook and the engaging part of the image forming apparatus main body side in the conventional lock mechanism.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an image forming apparatus provided with a locking mechanism of the present invention. In FIG. 1, reference numeral 100 denotes an image forming apparatus, and here, a digital multifunction peripheral is shown as an example. In the image forming apparatus 100, when performing a copy operation, in the image forming unit 3 in the multifunction machine main body 2, the charging device 4 uniformly charges the small-diameter photosensitive drum 5 that rotates in the A direction in the drawing. Next, an electrostatic latent image is formed on the photosensitive drum 5 by a laser beam from an exposure unit (laser scanning unit or the like) 7 based on the document image data read by the image reading unit 6, and electrostatically developed by the developing unit 8. A developer (hereinafter referred to as toner) is attached to the latent image to form a toner image. The toner is supplied to the developing unit 8 from the toner container 9.

  The sheet is conveyed from the sheet feeding mechanism 10 to the image forming unit 3 via the sheet conveying path 11 and the registration roller pair 12 toward the photosensitive drum 5 on which the toner image is formed as described above. 3, the toner image on the surface of the photosensitive drum 5 is transferred to the sheet by the transfer roller 13 (image transfer unit). The toner remaining on the surface of the photosensitive drum 5 is removed by the cleaning device 18. The charging device 4, the photosensitive drum 5, and the cleaning device 18 are unitized to form a drum unit 30 (see FIG. 2) that can be attached to and detached from the multifunction machine main body 2.

  The sheet onto which the toner image has been transferred is separated from the photosensitive drum 5 and conveyed to a fixing unit 14 having a fixing roller pair 14a to fix the toner image. The sheet that has passed through the fixing unit 14 is sent to a sheet conveyance path 15 branched in a plurality of directions, and is conveyed in a conveyance direction by path switching mechanisms 21 and 22 having a plurality of path switching guides provided at branch points of the sheet conveyance path 15. Are distributed as they are (or after being sent to the paper conveyance path 16 and double-sided copying), and discharged to the paper discharge section including the first discharge tray 17a and the second discharge tray 17b.

  Further, although not shown, a static elimination device that removes residual charges on the surface of the photosensitive drum 5 is provided on the downstream side of the cleaning device 18 with respect to the rotation direction of the photosensitive drum 5. Further, the paper feeding mechanism 10 is detachably attached to the multifunction machine main body 2 and includes a plurality of paper feeding cassettes 10a and 10b for storing paper, and a manual paper feeding mechanism (bypass unit) 10c provided above the paper feeding cassettes 10a and 10b. These are connected to the image forming unit 3 including the photosensitive drum 5, the developing unit 8 and the like by the paper transport path 11. At the upper end of the image reading unit 6, an openable / closable platen (original presser) 24 that presses and holds the original placed on the contact glass is provided.

  Specifically, the sheet conveyance path 15 first branches into a left and right fork on the downstream side of the fixing roller pair 14a, and one path (a path branching rightward in FIG. 1) communicates with the first discharge tray 17a. It is configured as follows. The other path (the path branching leftward in FIG. 1) branches up and down via the conveying roller pair 19, and the other path (the path branching leftward in FIG. 1) is the second discharge tray 17b. It is comprised so that it may communicate with. On the other hand, the other path (the path that branches downward in FIG. 1) is configured to communicate with the sheet conveyance path 16.

  FIG. 2 is a perspective view of a drum unit in which the charging device 4, the photosensitive drum 5, and the cleaning device 18 are unitized, and FIG. 3 is an enlarged view of an end portion on the upstream side in the insertion direction of the drum unit. In the drum unit 30, the charging device 4, the photosensitive drum 5, and the cleaning device 18 (see FIG. 1) are housed in a housing 31, and the end 31a of the housing 31 is connected to the multifunction device main body 2 (see FIG. 1). It is inserted in the direction of arrow B and pulled out in the direction of arrow B ′ from the end 31b side.

  On the end 31b side of the drum unit 30, a positioning boss 33 and a hook 35 are projected in the insertion direction (arrow B direction). A handle portion 37 that is gripped when the drum unit 30 is pulled out is provided at the lower end portion in the pulling direction (arrow B ′ direction).

FIG. 4 is a side view of the lock member provided on the end 31b side of the drum unit 30. FIG. The lock member 40 is bent substantially in a letter shape when viewed from the side, and is supported at a fulcrum 40b provided at the bent portion so as to be rotatable in the direction of the arrow AA '. The lock member 40 has a hook 35 formed at the downstream end portion in the insertion direction of the drum unit 30 and a handle portion 37 formed at the upstream end portion in the insertion direction.

  The lock member 40 is biased by the coil spring 41 in the engagement direction of the hook 35 (in the direction of arrow A in FIG. 4). Further, a protrusion 43 is formed at the tip of the hook 35, and when the lock member 40 is rotated, the engaging surface 35a (see FIG. 5) of the hook 35 draws an arc-shaped track S1, and the tip of the protrusion 43 Draws a trajectory S2 inside the trajectory S1. The lock member 40 is provided with a die hole 45 (see FIG. 3) that is required when the protrusion 43 is integrally formed with the hook 35.

  FIG. 5 is a side view showing a state in which the hook 35 and the engaging portion of the multifunction device main body 2 are engaged. The drum unit locking mechanism will be described with reference to FIGS. First, the drum unit 30 is inserted into the MFP main body 2 from the end 31a side. Then, the positioning boss 33 and the hook 35 on the end portion 31b side are pushed into the multifunction device main body 2 in accordance with the positions of the positioning hole and the engagement hole (not shown) of the multifunction device main body 2.

  At this time, in the conventional lock mechanism, since the protrusion 43 is not provided at the tip of the hook 35 as shown in FIG. 6, the locking surface 35a of the hook 35 is inserted to a position exceeding the track S1 in FIG. When the locking surface 35a is engaged with the engaging portion 50, the drum unit 30 is fixed. However, as shown in FIG. 6, the engaging surface 35 a of the hook 35 has a draft angle θ, and thus the engagement between the engaging surface 35 a and the engaging portion 50 may be insufficient. Further, since the engaging portion 50 is gradually engaged along the draft angle θ from the tip of the locking surface 35a, it is difficult to determine whether or not the hook 35 is completely engaged.

  On the other hand, in the lock mechanism of the present invention, by forming the protrusion 43 at the tip of the hook 35, the hook 35 and the engaging portion 50 are engaged unless the protrusion 43 is inserted to a position exceeding the track S2 in FIG. It has a configuration that does not. Therefore, the pushing amount of the drum unit 30 can be increased, and poor engagement between the hook 35 and the engaging portion 50 can be prevented beforehand.

  Further, when the protrusion 43 is inserted to a position exceeding the track S2, the locking member 40 is rotated in the direction of the arrow A by the biasing force of the coil spring 41, and the hook 35 is engaged with the engaging portion 50 vigorously. The user can easily confirm that the hook 35 is completely engaged to the base of the hook 35 by vibrations and engagement sounds generated when the hook 35 is engaged.

On the other hand, when the drum unit 30 is pulled out from the multifunction machine main body 2, if the handle portion 37 is lifted in the pulling direction (arrow B ′ direction), the lock member 40 resists the urging force of the coil spring 41 and the arrow A around the fulcrum 40 b. Rotate in the 'direction. Thereby, the engagement between the hook 35 and the engaging portion 50 is released. Then, the drum unit 30 can be pulled out from the multifunction machine main body 2 by holding the handle portion 37 as it is. In other words, the handle part 37 also serves as a release lever for releasing the lock mechanism of the drum unit 30, and the unlocking of the drum unit 30 and the pulling out of the drum unit 30 can be simultaneously performed by one operation of pulling the handle part 37 in the pulling direction. .

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the hook 35 and the handle portion 37 are formed at both ends of one lock member 40 so that the handle portion 37 also serves as a release lever of the lock mechanism. You may provide separately from the handle part for drawing out 30. FIG. Further, the release lever can be provided not on the drum unit 30 side but on the multifunction machine main body 2 side.

  Although the drum unit 30 has been described here as an example of the replacement unit, the lock mechanism of the present invention can be attached to and detached from the multifunction machine main body 2 such as the exposure unit 7, the developing unit 8, the toner container 9, and the fixing unit 14. The present invention can be applied to other units that are mounted in exactly the same manner.

  Further, the image forming apparatus on which the lock mechanism and the exchange unit of the present invention are mounted is not limited to the digital multi-function peripheral shown in FIG. 1, but other image forming apparatuses such as a color copying machine, a monochrome and color printer, and a facsimile machine. Of course, it can also be applied.

  INDUSTRIAL APPLICABILITY The present invention can be used for a lock mechanism of an exchange unit that is detachably mounted on an image forming apparatus, and is an L-shape that protrudes in the mounting direction of the exchange unit and engages with an engagement portion on the image forming apparatus main body side. A locking member that has a hook and a protrusion formed at the tip of the locking surface of the hook so as to face the engaging portion, and is rotatable in a direction orthogonal to the mounting direction of the replacement unit; An urging member that urges the lock member in a direction in which the hook and the engaging portion are engaged; and a release lever that rotates the lock member in a direction to release the engagement between the hook and the engaging portion. This is a lock mechanism for the replacement unit.

  By using the present invention, the replacement unit and the apparatus main body can be reliably locked, and a lock mechanism for the replacement unit that can easily check the locked state can be provided with a simple configuration.

2 Main body of multifunction device 4 Charging device 5 Photosensitive drum 9 Toner container 18 Cleaning device 30 Drum unit (exchange unit)
31 Housing 33 Positioning boss 35 Hook 35a Locking surface 37 Handle (release lever)
40 Lock member 41 Coil spring (biasing member)
43 Projection 45 Punching hole 50 Engagement unit 100 Image forming apparatus

Claims (5)

A locking mechanism that locks an exchange unit that is detachably attached to the image forming apparatus body in a state of being attached to the image forming apparatus body,
An L-shaped hook that protrudes in the unit mounting direction on the replacement unit side and engages with an engaging portion on the image forming apparatus main body side, and a unit mounting direction integrally formed at the tip of the locking surface of the hook. A locking member that has a protrusion protruding in the opposite direction and is rotatable in a direction orthogonal to the mounting direction of the replacement unit;
An urging member that urges the lock member in a direction in which the hook and the engaging portion are engaged;
A release lever that rotates the lock member in a direction to release the engagement between the hook and the engagement portion;
With
The locking surface draws an arcuate track S1 by the rotation of the lock member, and the tip of the projection draws an arcuate track S2 inside the track S1 by the rotation of the lock member,
When the replacement unit is inserted to a position where the engaging portion is inside the track S2, the locking member is rotated by the urging force of the urging member, and the protrusion comes into contact with the engaging portion, A lock mechanism of an exchange unit in which a hook and the engaging portion are engaged.   The lock mechanism of the replacement unit according to claim 1, wherein the release lever also serves as a handle portion of the replacement unit.   The locking mechanism of the replacement unit according to claim 1, wherein the protrusion is formed only at a substantially central portion in the width direction of the locking surface of the hook.   An exchange unit comprising the lock mechanism according to any one of claims 1 to 3. An image forming apparatus on which the replacement unit according to claim 4 is mounted.