JP3149784B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a laser beam printer, a facsimile, and a copying machine.

[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.

Further, the process unit remains in a floating state until the opening / closing cover is closed, and it is sometimes difficult to determine whether the process unit has been correctly mounted to a predetermined position.

The present invention provides an image forming apparatus capable of simplifying a cover for opening and closing a unit accommodating portion of a main body and various structures attached thereto to achieve cost reduction, and furthermore, confirms whether a process unit is correctly mounted. It is intended to be able to determine whether or not it is.

[0007]

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.

[0008] according to claim 1 invention comprises a unit housing portion 1a
Main body 1 having side wall 101 facing the unit housing portion
A process unit 2 including a cylindrical image carrier 210 and a component (for example, a developing device 23) for forming an image on the outer peripheral surface of the image carrier 210, and detachable from the unit accommodating portion 1a; And the unit housing portion 1a
Process unit 2 housed in unit housing unit 1a
The present invention is applied to an image forming apparatus which is urged in a discharge direction from the image forming apparatus. The process unit 2 includes a support shaft 211 that supports the image carrier 210 or a cylindrical body parallel to the image carrier 210 in the process unit 2, and the image carrier 2 on the support shaft 211.
And a spring means 216 for urging the support shaft 211 toward one end (the left end in FIG. 1) of the support shaft 211.
11 the other end of the (right end side in FIG. 1) protrudes to the outside of the process unit 2 by the repulsive force of the spring means 216, the side walls 1
01 , the process unit is opened in the unit accommodating portion 1a.
In a state where the unit 2 is housed in the unit housing unit 1a,
Groove 102 having a depth in the axial direction of the support shaft 211
Is provided, and the process unit 2 is accommodated in the unit housing portion 1a.
In the process of inserting the support shaft 211 into the groove 102,
Contacting the bottom surface 102a in the depth direction of the
Process unit 2 is collected while pressing 16
Insert the process unit 2 into the unit 1a
Of the groove 102 in the direction of insertion into the slot accommodation portion 1a
, The opening in the unit housing portion 1a, with respect to the axis Direction those
Has a depth greater than the depth of the groove 102 at the end
The recess 103 is provided, and the process unit 2
At the time when the housing portion 1a is housed to a predetermined position, the spring means
The other end of the support shaft 211 is
From the bottom surface 102a of the groove 102 that was in contact
The above-described object is achieved by the image forming apparatus that fits in the image forming apparatus.

According to the present invention, when the process unit 2 is accommodated to the predetermined position of the unit accommodating portion 1a, the projecting portion 211b of the support shaft 211 is fitted into the concave portion 103 by the force of the spring means 216 at that time. Thereby, the support shaft 21
1 is prevented from coming off in the discharge direction from the unit housing portion 1a, and the floating of the process unit 2 is prevented. When the support shaft 211 enters the recess 103, the feeling of mounting the process unit 2 changes, and the process unit 2
Can be determined to have been mounted to the predetermined position.

[0010] In the present invention of claim 2, the image forming apparatus according to claim 1, unit the process unit 2 accommodating portion 1
The depth of the concave portion 103 increases toward the direction of insertion (a lower side in FIG. 1) . In the present invention, the spring means 21
The support shaft 211 is pressed against the bottom surface 103a of the concave portion 103 by the force of 6, and the support shaft 211 is drawn into the unit housing portion 1a by the reaction force.

[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.

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, in the image forming apparatus according to the first and second aspects, the support shaft on the process unit side and the concave portion on the main body side are fitted to each other so that the process unit does not go through the opening / closing cover. Can be received by the main unit. As described above, since the process unit can be restrained in the unit accommodating portion without pressing the process unit with the opening / closing cover, it is not necessary to provide the opening / closing cover with high rigidity. Therefore, the opening / closing cover needs only to have a lightweight and simple structure. . There is no need for a mechanism to restrain the opening / closing cover in its closed position against the force that urges the process unit in the discharge direction.Therefore, the number of parts required for opening / closing the opening / closing cover and the assembly labor are reduced, and costs are reduced. Achieve down.

Moreover, it is possible to reliably determine whether or not the process unit has been properly mounted to a predetermined position by changing the sense of resistance when the process unit is mounted. Further, in the invention according to claim 2, the process unit is moved to the inside of the unit accommodating portion (the process unit is moved to the unit accommodating portion) by utilizing a reaction force when the support shaft is pressed against the bottom surface of the concave portion.
(In the direction of insertion) , so that the process unit can be more reliably prevented 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 accommodation part 2 ... Process unit 3 ... Opening / closing cover 10 ... Body frame 31 ... Rib (switching member) of opening / closing cover 40, 70 ... Restriction member 41 ... Torsion coil spring (spring member) 101 ... Unit accommodation part Side wall 103 ... recess in the side wall of the unit accommodating portion 106 ... receiving portion 160, 161 ... main body side drive gear 210 ... photosensitive drum (image carrier) 211 ... photosensitive drum support shaft 212, 234 ... input gear 216 ... Coil spring (spring means)

Continuation of the front page (56) References JP-A-4-291271 (JP, A) JP-A-7-92984 (JP, A) JP-A-62-210492 (JP, A) JP-A-1-75275 (JP) , U) Japanese Utility Model Showa 56-52770 (JP, U) Japanese Utility Model Application Hei 3-29972 (JP, U) Japanese Utility Model Showa 63-168468 (JP, U) Japanese Utility Model Showa 62-76374 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 21/16-21/18 G03G 21/00 350

Claims (2)

(57) [Claims] 1. A unit housing sectionAnd its unit compartment
With the side wall facingA cylindrical image carrier, and an image formed on an outer peripheral surface of the image carrier.
And a component for the unit housing.
And a detachable process unit, wherein the process unit accommodated in the unit accommodating portion is provided.
Is biased in the discharge direction from the unit storage section
In the forming apparatus, the process unit includes:
A support shaft for supporting the image carrier or a cylinder parallel to the image carrier
And the image carrier or the cylindrical body on the support shaft is
Spring means for urging the support shaft toward one end thereof,
The other end of the support shaft is resilient by the spring means.
Protruding outside the process unitWriting sideOn the wall,Open to the unit housing, and
Access unit is housed in the unit housing section
A groove having a depth in the axial direction of the support shaft in the state
Provided, Insert the process unit into the unit housing
In the process, the other end side of the support shaft is in a depth direction of the groove.
While contacting the bottom surface and compressing the spring means
The process unit is inserted into the unit housing.
And Insert the process unit into the unit housing
At the end of the groove in the direction,
Open and the groove at the end with respect to the axial direction.
A recess having a depth greater than the depth is provided, The process unit is located at a predetermined position in the unit housing unit.
At the time when it is stored up to the front by the urging force of the spring means.
The other end of the support shaft is in front of the groove that was in contact therewith.
From the bottom An image shape characterized by being fitted into the recess.
Equipment. 2. The process unit according to claim 1 , wherein
2. The image forming apparatus according to claim 1, wherein the depth of the recess increases as the direction of insertion into the container increases. 3.