JP3209224B2 - Image forming apparatus and process unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser beam printer, a facsimile, and a copying machine, and a process unit detachable from the image forming apparatus.

[0002]

2. Description of the Related Art As an apparatus of this type, a component for performing a series of image forming processes such as exposure, development and transfer, for example, a photosensitive drum or a developing device as an image carrier is called a process unit. In some cases, the process unit is integrated into a single unit, and the process unit is detachably attached to a unit accommodating portion of the apparatus main body. And, in the main body of the device,
An opening / closing cover for opening / closing the unit housing is attached.

[0003] In the apparatus having the above-mentioned configuration, there is a case where some force acts between the process unit and the main body, and the process unit is urged in the discharging direction from the unit accommodating portion.
For example, a contact for supplying a power supply voltage from the main body to the process unit side is formed in a coil spring shape, and the process unit may be lifted by the repulsive force. For this reason, conventionally, the process unit has been pressed into the unit accommodating portion by the opening / closing cover.

[0004]

However, when the process unit is pressed by the open / close cover, a mechanism for firmly restraining the open / close cover to the closed position is required so that the open / close cover is not opened by the reaction force from the process unit. Become. To prevent the opening / closing cover from being deformed by the reaction force from the process unit,
It was also necessary to give the opening and closing cover sufficient rigidity. Therefore, the cost is increased for the opening / closing cover and the mechanism attached thereto.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus and a process unit which can achieve a cost reduction by preventing a new cost for preventing the process unit from floating.

[0006]

Hereinafter, the present invention will be described with reference to the drawings showing embodiments of the present invention. However, the present invention is not limited to the illustrated embodiment.

According to the first aspect of the present invention, the unit accommodating portion 1a
And a main body 1 having a driving mechanism and a cylindrical image carrier 21
0 and the toner 231 on the image carrier 210.
And a process unit 2 which includes a developing unit 23 and a process unit 2 which is detachable from the unit accommodating portion 1a. When the process unit 2 is accommodated in the unit accommodating portion 1a, the first rotation transmitting element 160 of the driving mechanism Of process unit 2
The image bearing member rotation transmitting element 212 and are connected Rutotomoni, drive
Second rotation transmitting element 161 of the moving mechanism and process unit 2
Is applied to the image forming apparatus in which the power transmission to the image carrier 210 and the developing device 23 side of the process unit 2 is enabled by being connected to the developing device rotation transmitting element 234 . The receiving unit 106 to be engaged with the process unit 2 accommodated in the unit housing portion 1a is provided in the main body 1, the first rotation transmission element 160 of the drive mechanism of the process unit 2
More driving force Fa transferred to the image bearing member 210, receiving unit 10
Moment Ma generated around the center 6 and the driving mechanism
Of the process unit 2 from the second rotation transmitting element 161
The driving force Fb transmitted to the image device 23, the receiving portion 106
The second moment Mb generated as the center is opposite to each other
And the first moment Ma and the second moment
Combined moment M generated by combination with moment Mb
The position of the receiving portion 106 is set such that c is a direction in which the process unit 2 is drawn into the unit accommodating portion 1a, thereby achieving the above-described object.

According to the present invention, the first rotation transmitting element of the main body 1 is provided.
160 and the second rotation transmitting element 161 to the image carrier 210 of the process unit 2 and the developing device 23 to drive force Fa,
When Fb is transmitted, the first moment Ma and the second moment Mb move around the receiving portion 106 accordingly.
It occurs in the opposite direction. Therefore, the first mom
Is generated by the combination of the component Ma and the second moment Mb.
Since the formation moment Mc does not become so large,
Of the process unit 2 by the
Is done. Further, the resultant moment Mc acts in a direction to draw the process unit 2 into the unit accommodating portion 1a .
Therefore , the lifting of the process unit 2 is prevented.

According to the second aspect of the present invention, the cylindrical image carrier 210 is detachable from the unit accommodating portion 1a of the image forming apparatus, and the toner 231 is applied on the image carrier 210.
This is applied to the process unit 2 having the developing device 23 for attaching. Then, when housed in the unit housing section 1a, the first rotation transmission element of the drive mechanism of the image forming apparatus
It is connected to the 160 and the image bearing member rotation transmitting element 212 to which the power to the image carrier 210 is can be transmitted, the unit housing portion
1a, the second drive mechanism of the image forming apparatus
The power is connected to the rotation transmitting element 161 to the developing device 23.
The developing device rotation transmitting element 234 that can be transmitted and the unit housing portion 1a when housed in the unit housing portion 1a.
An engaging portion 205 that engages is provided in the receiving portion 106 formed in, Zo担 from the first rotation transmission element 160 of the drive mechanism
More driving force Fa transferred to the bearing member 210, a first moment Ma generated around the engagement portion 205, the driving mechanism
Driving force transmitted from two-rotation transmitting element 161 to developing device 23
The second mode generated around the engagement portion 205 by Fb
So as to be opposite to each other.
One, synthesis of the first moment Ma and the second moment Mb
Synthesis moment Mc is the unit housing portion 1a caused by
The above-described object is achieved by setting the position of the engagement portion 205 so as to be in the direction of being drawn into the inside.

According to the present invention, the first rotation transmission of the image forming apparatus is performed.
When the driving forces Fa and Fb are transmitted from the transfer element 160 and the second rotation transmitting element 161 to the image carrier 210 and the developing device 23 of the process unit 2 , the engaging portions 205 are correspondingly transmitted.
The first moment Ma and the second moment Mb around
It occurs so that the directions are opposite to each other. Therefore, the first
Generated by combining the moment Ma and the second moment Mb
Because the resultant moment Mc does not become so large,
Torsion of process unit 2 due to resultant moment Mc
Is prevented. Further, composite moment Mc is in a direction to pull the process unit 2 into the interior of the unit housing portion 1a
Since it works , the lifting of the process unit 2 is prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 5 schematically shows a laser beam printer as an embodiment of the image forming apparatus of the present invention. As is clear from this figure, the laser beam printer according to the present embodiment includes a main body 1 having a unit accommodating portion 1a, a process unit 2 detachably accommodated in the unit accommodating portion 1a, and An opening / closing cover 3 attached to the upper side of the main body 1 is provided to make it possible. The opening / closing cover 3 is connected to the main body 1 such that the opening / closing cover 3 can be opened and closed in a vertical direction about a fulcrum provided on a rear end side (a left end side in FIG. 6).

The main body 1 includes a main body frame 10 made of a material such as resin, a paper feed unit 11 attached to the rear end of the main body frame 10, and a unit housing 1.
a, a fulcrum 1 on the front side of the main body frame 10;
Paper output tray 15 that can be opened and closed via 50
And a drive unit 16 inserted into one side of the main body frame 10 through an opening (not shown) on the lower surface side of the main body frame 10. Inside the drive unit 16, an electric motor as a drive source and a gear train (not shown) for transmitting the rotation thereof are provided. Body frame 10
A restraining mechanism 4 for the opening / closing cover 3 is provided on the right upper surface of the device, and its details will be described later. The laser scanner unit 12 is fixed to a bottom position of the unit housing section 1a, and the process unit 2 is housed above the laser scanner unit 12.

As shown in FIG. 6, the paper feeding unit 11 is provided with a push-up plate 110 on which the paper P is loaded, and the paper P loaded thereon is fed by the force of a spring 111 to the paper feed roller 1.
12 and the paper holding collar 113. In this state, the paper feed roller 112 rotates in the direction of the arrow in FIG. 6 and the paper P is sent out from the push-up plate 110. At this time,
The separation of the papers P is promoted by the inclination of the separation wall 114 disposed in front of the push-up plate 110 and the force of the spring 115 pressing the separation wall 114 toward the paper feed roller 112. As a result,
The uppermost sheet P stacked on the push-up plate 110 is separated from other sheets P and sent out by the registration rollers 116 and 117. The movement path of the sheet P up to the sheet discharge tray 15 is indicated by a dashed line PP in the figure.

A laser light generator 120 is provided inside the laser scanner unit 12, and the laser light emitted from the generator 120 is, as shown by an arrow in FIG.
Polygon mirror 121, lens 122, mirror 123,
It is guided onto a photosensitive drum 210 as an image carrier of the process unit 2 via a lens 124 and a mirror 125. The polygon mirror 121 is driven to rotate around its vertical axis in synchronization with the emission of the laser beam, and the laser is driven in the axial direction of the photosensitive drum 210 as an image carrier (a direction perpendicular to the plane of FIG. 6) with the rotation. Light is scanned.

The process unit 2 has a frame 20 made of a resin or the like.
Photosensitive drum device 21, charger 22, developing device 23
And a transfer roller device 24. The photosensitive drum device 21 is provided with a photosensitive drum 210 as an image carrier, and the transfer roller device 24 is provided with a transfer roller 240. These are respectively driven by the driving force supplied from the drive unit 16 (see FIG. 5). Is driven to rotate in the direction of the arrow in FIG. Details will be described later. The charger 22 generates a corona discharge to cause the photosensitive drum 210
Is charged. The outer periphery of the charged photosensitive drum 210 is irradiated with the laser beam from the laser scanner unit 12 described above, and a potential difference is generated between the irradiated portion and the non-irradiated portion to form an electrostatic latent image.

The developing device 23 supplies the toner 231 contained in the toner box 230 to the outer peripheral side of the photosensitive drum 210 via the supply roller 232 and the developing roller 233. The supplied toner 231 adheres to the photosensitive drum 210 according to the charged state of the photosensitive drum 210, whereby a visible image corresponding to the electrostatic latent image is formed (developed) on the photosensitive drum 210.

The transfer roller 240 is disposed in contact with the upper end of the photosensitive drum 210, and the sheet P is guided to these contact positions. A constant electric field is formed between the photosensitive drum 210 and the transfer roller 240, and the toner image on the photosensitive drum 210 is transferred to the sheet P by the electric field. After the transfer, the photosensitive drum 210 is prepared for the next formation of the electrostatic latent image.
The upper residual toner is removed by the cleaning roller 25,
The charge remaining on the photosensitive drum 210 is removed by the charge removing lamp 26. The residual toner transferred to the cleaning roller 25 is returned to the photosensitive drum 210 at an appropriate timing (a timing that does not hinder the formation of an electrostatic latent image or the like), and the returned toner is developed through the developing roller 233. Collected in the device 23. As described above, inside the process unit 2, the photosensitive drum device 21 and the charger 22, the developing device 23, and the transfer roller which are components for forming an image on the outer peripheral surface of the photosensitive drum 210 as an image carrier are formed. A device 24 is provided.

The fixing unit 14 includes the process unit 2
Is disposed adjacent to the downstream side of the sheet P in the transport direction. The fixing unit 14 has a pair of rollers 140 and 141.
Is provided. The sheet P onto which the toner image has been transferred is guided between the rollers 140 and 141 and pressed, and in this state, the sheet P is heated by heating means (not shown) such as a halogen lamp provided on one of the rollers (for example, 140). P is heated. By this pressing and heating, the toner image on the paper P is fixed. The sheet P after fixing is formed by a pair of discharge rollers 142,
The sheet is discharged onto the sheet discharge tray 15 by 142.

Next, a configuration for preventing the process unit 2 from floating will be described with reference to FIGS.
Note that the horizontal direction in FIGS. 1 to 3 coincides with the horizontal direction when the laser beam printer is viewed from the front side (the side where the paper discharge tray 15 is attached).

FIG. 1 shows that the process unit 2 is
10 shows a state viewed in cross section along the axial direction of No. 10. As is clear from this figure, the photosensitive drum device 21 includes a photosensitive drum 210 and a support shaft 211 for supporting the photosensitive drum 210. The photosensitive drum 210 is a thin cylindrical body (for example, an aluminum tube) formed of a conductive material.
Is covered with a photosensitive layer. Photosensitive drum 210
The gear 213 is on the left end side, and the support flange 2 is on the right end side.
The center of the gear 213 and the center of the support flange 214 are supported on a support shaft 211 so as to be rotatable and movable in the axial direction. Therefore, the photosensitive drum 210 is movable coaxially with the support shaft 211 in both the circumferential direction and the axial direction with respect to the support shaft 211.

The support shaft 211 is supported by bearings 200 and 201 provided on the frame 20 of the process unit 2 so as to be movable in the axial direction.
1b protrudes outside the frame 20 (see FIG. 5). Projecting end 21 from right side surface 202 of frame 20
1b is rounded into a spherical shape. An input gear 212 is attached to the outside of the gear 213 so as to be integrally rotatable. A coil spring 216 is mounted between the retaining ring 215 fixed on the support shaft 211 and the support flange 214, and the repulsive force of the coil spring 216 causes the photosensitive drum 210 and the gear 21 to move.
2, 213 and the support flange 214 are urged toward the bearing portion 200, so that their backlash in the axial direction is suppressed.

A transfer roller 240 of the transfer roller device 24 contacts the upper end of the photosensitive drum 210, and the transfer roller 240 is rotatably supported by the frame 20 via a support shaft 241. A gear 24 is provided on the left end side of the support shaft 241.
2, and a gear 242 thereof meshes with a gear 213 of the photosensitive drum device 21. Therefore, the input gear 212
Is rotated, the photosensitive drum 210 and the transfer roller 2
40 rotate in opposite directions about each other's axis.

A charger 22 is arranged below the photosensitive drum 210. The charger 22 is provided with left and right holding walls 220 and 221 integrated with the frame 20, a charging wire 222 laid therebetween in parallel with the photosensitive drum 210, and disposed between the charging wire 222 and the photosensitive drum 210. Grid 223. The charging wire 222 is pulled in the longitudinal direction by a torsion coil spring 224 supported by the right holding wall 221, and is electrically connected to the electrode 225 at the lower end of the right holding wall 221 via the torsion coil spring 224.

A contact portion 5 is provided on the right bottom portion of the unit accommodating portion 1a of the main body 1 in correspondence with the electrode 225 described above. When the process unit 2 is mounted in the unit housing portion 1a, the electrode member 50 of the contact portion 5
5 makes it possible to apply a voltage to the charging wire 222 from a high-voltage power supply circuit (not shown) in the main body 1.

FIG. 2 shows the details of the contact portion 5. The contact portion 5 includes an electrode member 50 formed in a coil spring shape, a support cylinder 51 provided integrally with the main body frame 10 to support the electrode member 50, and a contact 6 between the electrode member 50 and the circuit board 6.
A contact member 52 in the form of a leaf spring that conducts with zero. Each of the electrode member 50 and the communication member 52 is made of a conductive material.

The electrode member 50 is provided with a tightly wound portion 500 and a non-closely wound portion 501 with the XX line in the drawing as a boundary, and the non-closely wound portion 501 projects upward from the support cylinder 51. To contact the electrode on the process unit 2 side. The distal end side of the communication member 52 is inserted into the tightly wound portion 500 through the through hole 510 of the support cylinder 51, and thereby the electrode member 50 is supported. According to such a configuration, the contact between the electrode member 50 and the electrode of the process unit 2 is ensured by the spring force of the non-contact winding portion 501. Moreover, even if the insertion position of the connecting member 52 changes up and down within the range of the tightly wound portion 500, the spring force acting between the non-tightly wound portion 501 and the electrode on the process unit 2 side is kept constant.

Before inserting the connecting member 52, the electrode member 5
0 is inserted into the support cylinder 51 from below. At that stage, a hook portion 502 is provided at the lower end of the electrode member 50 in order to hook the electrode member 50 on the support cylinder 51 and prevent the electrode member 50 from dropping.

After the leading end of the connecting member 52 is inserted into the electrode member 50, the connecting member 52 is fixed to the boss 54 by a mounting screw 53. The boss 54 is integral with the main body frame 10. A bent portion 52 protruding toward the opposite side (the upper side in FIG. 2) of the connecting member 52 on the side opposite to the screwing direction of the mounting screw 53 is provided on the tip side.
0 is provided. When the mounting screw 53 is tightened, the connecting member 52 is elastically deformed so that the bent portion 520 expands, and the connecting member 52 is pressed against the lower end of the inner peripheral surface of the hole 510 by a repulsive force against the connecting member 52. Thereby, the mounting screw 53
Connecting member 52 between the mounting position of
The rattling is prevented, and the electrode member 50 supported by the communication member 52 is stably supported in the vertical direction. Communication member 5
The contact portion 521 on the rear end side of the pair 2 is pressed against the contact 60 by the spring force of the connecting member 52.

In the above description, the contact portion 5 has been described as corresponding to the charging wire electrode 225 of the charger 22. However, in the process unit 2 of the present embodiment, in addition to the electrode 225, various high-voltage electrodes (for example, a charging device) 22 grids 223
And an electrode for applying a voltage to the developing roller 233 of the developing device 23 are provided side by side on the lower right side of the frame 20. Correspondingly, a plurality of the above-mentioned contact portions 5 are arranged side by side on the right end side of the unit accommodating portion 1a of the main body 1. Therefore, when the process unit 2 is inserted into the unit accommodating portion 1a, the right end side of the process unit 2 is pushed upward by the spring force of the electrode member 50 of each contact portion 5.

In order to hold the process unit 2 in the unit accommodating portion 1a against such a spring force, in this embodiment, the support shaft 211 of the photosensitive drum device 21 described above is used.
And a restraining mechanism 4 shown in FIG. Hereinafter, description will be made in order.

As shown in FIG. 1, a side wall 101 facing the unit accommodating portion 1a of the main body frame 10 is provided with a groove portion 102 extending vertically (see FIG. 5). When the process unit 2 is mounted, the groove 102
The protruding end 211b of the support shaft 211 provided on the photosensitive drum device 21 is inserted. The bottom surface 102a of the groove 102
Are inclined such that the depth of the groove 102 with respect to the side wall 101 decreases toward the inside (lower side in FIG. 1) of the unit housing portion 1a. A recess 103 is provided at the lower end of the groove 102. The position of the concave portion 103 depends on the protruding end portion 2 of the support shaft 211 when the process unit 2 is inserted into the unit accommodating portion 1a to a predetermined position.
11b. The bottom surface 103a of the recess 103 is
A predetermined angle θ in the direction opposite to the bottom surface 102a of the groove 102 with respect to the vertical direction so that the depth of the concave portion 103 with respect to the side wall 101 increases toward the inside of the unit accommodating portion 1a.
Just tilted.

According to such a configuration, the bottom surface 102a of the groove 102 comes into contact with the protruding end 211b of the support shaft 211 during the process of inserting the process unit 2, and the bottom surface 102a
, The support shaft 211 gradually moves to the left side of the process unit 2 (the side on which the gears 212 and 213 are provided) while pressing and contracting the coil spring 216. When the process unit 2 is inserted to a predetermined position, the protruding end 211b is inserted into the recess 103 by the force of the coil spring 216. At this time, since the bottom surface 103 a of the concave portion 103 is inclined as described above, a downward reaction force acts on the protruding end portion 211 b according to the repulsion force of the coil spring 216. Therefore, the right end of the process unit 2 is prevented from floating.

The protruding end 211b is located on the bottom surface 10 of the groove 102.
2a, the upward reaction force is generated by the inclination of the bottom surface 102a and the force of the spring 216 to generate the upward end portion 211b.
The upward reaction force acting on the protruding end 211b increases in proportion to the increase in the repulsion force of the coil spring 216 as the insertion amount of the process unit 2 increases. Therefore, when the protruding end portion 211b moves to the concave portion 103, the resistance to the insertion of the process unit 2 is clearly changed (in this case, the resistance is reduced). It can be reliably determined that the camera has been mounted to the position.

As shown in FIG. 3, the restraining mechanism 4 moves the release position A (FIG.
(A)) and a restraining member 40 rotatably supported between a restraining position B (FIG. 3B) and a protruding shaft 40 of the restraining member 40.
0, a torsion coil spring 41 supported by
Member 4 attached between the body frame 10
0 to the release position A. One arm 410 of the torsion coil spring 41 is locked by the spring hook 401 of the restraining member 40, and the other arm 41
Reference numeral 1 extends to a gap S provided between the restraining member 40 and the main body frame 10. On the inner surface 30 of the opening / closing cover 3,
A rib 31 is formed corresponding to the gap S.

In the above configuration, when the opening / closing cover 3 is open, the restraining member 40 is moved to the release position A by the return spring 42.
Is held. In this state, the restraining member 40 retreats laterally beyond the engaging portion 204 provided at the upper right end of the frame 20 of the process unit 2. Therefore, the process unit 2 can be freely attached to and detached from the unit accommodating portion 1a.

When the cover 3 is closed, the ribs 31 enter the gap S while pushing down the arm 411 of the torsion coil spring 41. Due to the repulsive force of the torsion coil spring 41 at this time, the restraining member 40 is pushed clockwise around the support shaft 104 and moves to the restraining position B, and the convex arc-shaped restraining surface 402 formed at the lower end thereof is moved to the process unit. 2 rides on the engaging portion 204. In this state, the force for pushing up the process unit 2, that is, the spring force of the contact portion 5 described above acts on the contact position between the engagement portion 204 and the constraint surface 402.
By arranging the support shaft 104 in the direction in which the force acts, most of the force pushing up the process unit 2 can be received by the support shaft 104 via the restraining member 40. A part of the force for pushing up the process unit 2 acts in the direction of returning the restraining member 40 to the release position A, but the force of the torsion coil spring 41 acts in the opposite direction. Unless raised from
The restraint member 40 does not return to the release position A. Moreover,
The rib 31 is pressed against the receiving surface 105 of the main body frame 10 by the arm 411 of the torsion coil spring 41. For this reason, a frictional force acts between the rib 31 and the receiving surface 105, and the opening / closing cover 3 is held at the closed position.

As described above, in the present embodiment, the spring force of the contact portion 5 acting on the right end side of the process unit 2 has two paths set to avoid the open / close cover 3, namely,
One is the support shaft 2 from the frame 20 of the process unit 2.
11 through the bottom surface 10 of the concave portion 103 of the main body frame 10
The path leading to the main frame 10a from the frame 20 of the process unit 2 via the restraining member 40
Of the main body frame 10 through a path to the support shaft 104 of the
It is accepted.

Next, in this embodiment, a lifting prevention means is also provided on the left side surface 203 (see FIG. 1) of the process unit 2, and this will be described with reference to FIG. The vertical and horizontal directions in FIG. 4 correspond to those in FIG.

As shown in FIG. 4, the process unit 2
An input gear 212 for the above-described photosensitive drum 210 and an input gear 234 for driving each part of the developing device 23 are provided on the left side surface 203 of the developing device 23. When the process unit 2 is accommodated in the unit accommodating portion 1a, these input gears 212 and 234 mesh with drive gears 160 and 161 provided on the drive unit 16 in the main body frame 10, respectively. Rotation) supplied from a motor (not shown) in the driving gear 1
The signals can be transmitted to the input gears 212 and 234 via the gears 60 and 161 respectively. The rotation direction of each gear is as shown by the arrow in the figure.

Here, when the rotation is transmitted from the driving gears 160, 161 to the input gears 212, 234, the driving forces Fa, Fb act on their meshing positions. The directions of action of these driving forces Fa and Fb are inclined by an angle equal to the pressure angle α of each gear toward the driven gears 212 and 234 with respect to the tangent lines Ca and Cb at the meshing position of each gear. The process unit 2 is pushed up in the discharge direction (the direction of the arrow U) by the vertical upward component force.

Therefore, in this embodiment, an engaging portion 205 that engages with the receiving portion 106 of the main body frame 10 is provided at the rear end of the process unit 2. The position of the contact point D between the engaging portion 205 and the receiving portion 106 is determined by the resultant moment Mc corresponding to the driving forces Fa and Fb around the contact point D in the clockwise direction in FIG.
Is set so as to act in the direction of pulling into the unit accommodating portion 1a. Specifically, when the lengths of the arms with respect to the contact point D of the driving forces Fa and Fb are La and Lb, respectively,

[0042]

## EQU1 ## The position of the contact point D is set so that Fa.La <Fb.Lb.

For this reason, when the driving forces Fa and Fb act, the process unit 2 generates a resultant moment Mc corresponding thereto.
Is pulled into the unit housing portion 1a.
Note that if the resultant moment Mc is set too large, the process unit 2 will be twisted. Therefore, it is desirable to limit the resultant moment Mc to a minimum value or a value near the minimum value at which the floating of the process unit 2 can be prevented. For this reason, in the present embodiment, the moments Ma and Mb respectively corresponding to the driving forces Fa and Fb are applied in opposite directions around the contact point D, and the position of the contact point D is adjusted so that the difference becomes the combined moment Mc. It was set. The same applies to a case where three or more gears are provided.

As described above, in the present embodiment, the process unit 2 can be restrained in the unit accommodating portion 1a without being held by the opening / closing cover 3, so that the mechanism for holding the process unit 2 or the process unit 2 Therefore, there is no need to provide a mechanism for restraining the opening / closing cover 3 at the closed position against the reaction force. Further, the rigidity of the opening / closing cover 3 may be small. Accordingly, the weight of the opening / closing cover 3 can be reduced, and parts required for opening / closing and opening / closing the opening / closing cover 3 can be reduced, thereby achieving cost reduction.

The present invention is not limited to the above embodiment, but can be variously modified. For example, the restraint mechanism 4 of FIG.
May be provided with the restraint mechanism 7 of FIG. In the restraining mechanism 7, the restraining member 70 is provided between the right side surface 202 of the process unit 2 and the main body frame 10. The restraining member 70 is formed by forming a spring material into a plate shape, and is fixed to the main body frame 10 at a lower end thereof. In the middle of the restraining member 70, a unit locking portion 700 that bends toward the process unit 2 and a cover locking portion 701 that bends in the opposite direction are formed. A wedge-shaped enlarged portion 310 is provided at the end of the rib 31 of the opening / closing cover 3.

When the cover 3 is closed, FIG.
As shown in (b), the enlarged portion 310 is formed by the cover locking portion 701.
While entering the space between the restraining member 70 and the receiving surface 107 of the main body frame 10 while pushing back, the unit locking portion 700 of the restraining member 70 engages with the process unit 2.
Thus, the force for pushing up the process unit 2 is received by the main body frame 10 via the restraining member 70.
Further, the rib 31 is pressed against the receiving surface 107 by the cover locking portion 701 of the restraining member 70, whereby the opening / closing cover 3 is restrained at the closed position. To open the opening / closing cover 3, the enlarged portion 310 may be pulled out while bending the cover locking portion 701 to the opposite side to the receiving surface 107.

In the above embodiment, the restraining members 40, 70
7 and the combination of the rib 31 and the torsion coil spring 41 (in the case of FIG. 3) or only the rib 31 (in the case of FIG. 7) as the switching means, and the enlarged portion of the rib 31 of FIG. 310 and cover locking portion 7 of restraining member 70
01 corresponds to each of the pair of engagement portions.

In the above embodiment, the case where the right side of the process unit 2 is pushed up by the spring force of the contact portion 5 and the left side is pushed up by the driving forces Fa and Fb, but the present invention is applied to such an example. The present invention can be applied to any case where the process unit 2 floats without limitation. The restraining means using the restraining mechanism 4 and the support shaft 211 may be appropriately used depending on the state of the process unit 2 floating. When a shaft urged to one end side in the axial direction by the spring means is present in the process unit 2 in addition to the support shaft 211 of the photosensitive drum 210, the shaft is replaced or added to the path forming means. Available as The torsion coil spring 41 is omitted and the restraining member 40 and the rib 31 are omitted.
May be directly contacted. The return spring 42 may be omitted.

[0049]

As described above, according to the present invention, the process unit can be prevented from being lifted by utilizing the driving force transmitted from the main body of the image forming apparatus to the process unit, and the process unit can be prevented against the driving force. Since there is no need to provide a separate mechanism for pressing the process unit, no additional cost is required to prevent the process unit from floating.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an internal structure of a process unit provided in a laser beam printer according to an embodiment of the present invention along an axial direction of a photosensitive drum.

FIG. 2 is a sectional view showing a structure of a contact portion provided on a main body for supplying a high voltage to a process unit in the laser beam printer of FIG.

FIG. 3 is a view showing a restraining mechanism for an opening / closing cover provided to prevent the right end side of the process unit of FIG. 1 from floating.

FIG. 4 is a view showing a structure for preventing a left end of the process unit shown in FIG. 1 from rising.

FIG. 5 is an exploded perspective view schematically showing the laser beam printer according to the embodiment of the present invention.

FIG. 6 is a longitudinal sectional view schematically showing a laser beam printer according to the embodiment of the present invention.

FIG. 7 is a view showing another embodiment of a restricting mechanism for an opening / closing cover provided to prevent the right end side of the process unit shown in FIG. 1 from floating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 1a Unit accommodating part 2 Process unit 3 Opening / closing cover 10 Main body frame 31 Rib (switching member) of an opening / closing cover 40, 70 Restriction member 41 Torsion coil spring (spring member) 101 Side wall of unit accommodating part 103 Side wall of unit accommodating part Concave portion 106 Main body receiving portion 160, 161 Main body side driving gear 205 Engaging portion 210 Photosensitive drum (image carrier) 211 Photosensitive drum support shaft 212, 234 Input gear 216 Coil spring (spring means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 21/16 G03G 21/18 G03G 15/08-15/095

Claims (2)

(57) [Claims] A main body having a unit accommodating portion and a driving mechanism; a cylindrical image carrier; and toner adhering on the image carrier.
A process unit that includes a developing unit for causing the unit to be attached to and detached from the unit housing. When the process unit is housed in the unit housing, a first rotation transmission element of the drive mechanism is provided . co when the image bearing member rotation transmitting element of said process unit Ru is connected
The second rotation transmitting element of the drive mechanism and the process unit
And a developing unit rotation transmitting elements knit are connected, an image forming apparatus which power transmission is possible to the image bearing member and said developing device side of the process unit, housed in the unit housing portion A receiving portion that engages with the process unit is provided on the main body, and a first force generated around the receiving portion by a driving force transmitted from the first rotation transmission element of the drive mechanism to the image carrier of the process unit . Moment and the drive
From the second rotation transmitting element to the process unit.
The receiving portion is centered by the driving force transmitted to the developing device.
And the second moment generated as
And the first moment and the second mode
An image forming apparatus, wherein the position of the receiving portion is set such that a synthetic moment generated by synthesizing the process unit and the process unit is in a direction of drawing the process unit into the unit accommodating portion. 2. A cylindrical image carrier detachably mountable to a unit accommodating portion of an image forming apparatus, and said image carrier.
In the process unit having a developing device for applying toner to the above, the time which is accommodated into the unit housing portion, said image being connected to the first rotation transmission element of the drive mechanism of the image forming apparatus responsible
An image bearing member rotation transmitting element power is set to be transmitted to the lifting member, when accommodated into the unit housing portion, the image forming instrumentation
Connected to the second rotation transmitting element of the drive mechanism
A developing device rotary transduction element power is set to be transmitted to the device
If, when accommodated into the unit housing portion, and the engaging portion is provided to be engaged with the receiving portion formed in the unit housing portion, said image bearing member from said first rotation transmission element of the drive mechanism < generated around the engaging portion by the driving force transmitted to the
A first moment and the second rotation transmission of the drive mechanism.
The engaging portion is driven by a driving force transmitted from the element to the developing device.
And the second moment generated around
Direction, and the first moment and the
Process unit, wherein a synthesized moment generated by the synthesis of the 2 moment the position of the engaging portion such that the direction of pulling to the inside of the front <br/> SL unit housing portion is set.