JPH10293518A - Process unit for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the assembling of a photoreceptor unit and a developing device unit, and the holding of the photoreceptive unit in an image recorder provided with the photoreceptor unit and the developing device unit combinedly. SOLUTION: In a developing device unit 30 arranged on the image forming part of the image recorder, a pair of supporting plate 40 is protrudingly provided on a photoreceptor unit 60 side, a recessed groove 41 and a hook member 42 are provided on the plates 40, and the shaft 66 and a pin 63 of the unit 60 are inserted in the groove 41, so that the both units are assembled. In the case of assembling both units 30 and 60, the shaft core of the shaft 66 of photoreceptor drum 65 is positioned lower than the position of the shaft core of the shaft of a developing roller 35, so that operation for pressuring the drum 65 downward by the rotation of the roller 35 is generated; therefore, the unit 60 is prevented from floating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus in which an image forming section is constituted by using two units, that is, a photosensitive unit and a developing unit. The present invention relates to a process unit of an electrophotographic apparatus provided with a combination mechanism and a unit capable of favorably setting the relationship between the axis of a photosensitive drum and the axis of a developing roller.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus using an electrophotographic system, a process unit in which a photosensitive drum, a charger, a developing unit, and the like are integrally formed has been used. It is provided detachably. In the case where the integrated process unit is configured as a unit capable of copying 10,000 sheets, for example, the life of the unit is estimated by using the count value of a counter provided in the image forming apparatus. , Such as instructing replacement of the unit. Therefore, when the above-described unit is used, it is not necessary to pay particular attention to the life of the photosensitive drum, the developing device, and the like. The image recording apparatus can be used only by replacing the process unit.

However, the photosensitive drum and the developing device disposed in the process unit are consumables, and when each of these members reaches the end of their life, they are replaced with new units. There is a big difference in the lifespan. If these members having different lifespans are collectively replaced, any of the members will be wasted.
Therefore, there is also used an apparatus in which the photosensitive drum unit and the developing unit are separately formed, and each unit is replaced according to the life of the unit.

[0004]

In the case where the two units are configured to be separately replaceable, no waste occurs in each unit. On the other hand, when a paper jam or the like occurs in the paper transport path. In this case, it is necessary to remove the two units from the apparatus main body and perform the jam processing, which causes a new problem that the attaching and detaching work of the units is troublesome. Also, when the photosensitive unit and the developing unit are combined and arranged in the image forming section of the apparatus main body, the mutual positional relationship between the photosensitive drum of the photosensitive unit and the developing roller of the developing unit is accurately set. There is a need to. However, in the case of arranging two conventional units in combination, a mechanism for setting a mutual relationship between these units becomes complicated because a means such as mounting each unit to the main body frame is used. And so on.
Furthermore, when the two units are combined, it is difficult to position the photosensitive drum provided on the photosensitive unit and the developing roller of the developing unit relative to each other, so that the two rotating members can be accurately and easily positioned. There is a need for the development of positionable means.

The present invention solves the problems of the conventional apparatus as described above, and combines two units of a photoreceptor unit and a developing unit so that they can be integrally attached and detached and arranged in both units. It is an object of the present invention to provide a device capable of accurately positioning the rotating members relative to each other.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an image recording apparatus for forming a toner image on a photosensitive drum by using an electrophotographic method, and transferring the toner image to paper to make a copy. According to a first aspect of the present invention, the photoconductor unit and the developing unit are formed separately, and both units are provided with detachable means that can be separated from each other, and the photoconductor drum is in a state where both units are engaged. Is arranged below the axis of the developing roller arranged in the developing unit. In the present invention, the photoreceptor unit and the developing unit can be individually replaced according to their respective service lives, and when performing processing such as paper jam, the two units are integrated into the apparatus body. Can be taken from. Further, since the two rotating members are pressed against each other and rotated in the same direction due to the positional relationship between the two rotating members of the photosensitive drum and the developing roller, a downward force accompanying the rotation acts. In addition, the lifting of the photoconductor unit is suppressed, and the mutual positional relationship between the two units can be favorably maintained.

According to the second aspect of the present invention, a pair of support members are provided so as to protrude from the end of the developing unit toward the photosensitive drum, and the end of the photosensitive drum unit is vertically connected to the end of the drum shaft. A pin member and two protruding members are provided, and the drum shaft end of the photoreceptor unit and a pin member are mounted in an engagement groove provided in the support piece to engage the two units. I do. Then, the two units can be integrated in a predetermined positional relationship by engaging the shaft of the photoconductor unit and the pin member with the engagement groove provided in the support member of the developing unit. According to a third aspect of the present invention, the engaging groove provided in the support member of the developing unit is provided with a locking member that is elastically deformed as the pin end of the drum shaft is inserted into and removed from the drum shaft. I do. Therefore, when the protruding member of the photoreceptor unit is mounted in the concave groove of the support member of the developing device unit, it can be pressed and held by the elastic member, and the mounting state can be visually checked.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an image recording apparatus to which the apparatus of the present invention can be applied will be described with reference to FIG.
The image recording apparatus 1 shown in FIG. 1 can be configured as an image forming apparatus such as a small printer or a facsimile, and a paper feed cassette for accommodating sheets of any size is mounted on a main body 2 of the apparatus. And means for feeding the paper toward the paper transport path 3. The paper transport path 3 is a main body 2
The sheet is formed between the upper frame 4 and the upper guide plate 5, and is positioned at the leading end of the sheet by a conveying roller device 6 which functions as a registration roller device, and is conveyed toward the image transfer section. Then, the toner image formed on the photosensitive drum 65 is transferred to a sheet by discharging the transfer roller 71, and is sent to a fixing device. In this embodiment, the image forming unit 8 of the image recording apparatus is used.
And a combination of a developing unit 30 and a photoreceptor unit 60. The two units are mounted on positioning means provided in an image forming unit of the apparatus main body, as described later. Is done.

The two units are detachably provided via a top cover 10 which can be opened and closed at the top of the apparatus main body. One end of the top cover 10 is supported by a hinge 11 provided on an upper frame of the apparatus main body as a fulcrum, and a lock member 12 is provided at the other end of the top cover 10 via a support shaft 13. The lock member 12 includes a lever 14 supported by a support shaft 13 and an engagement claw 15. The top cover 10 is locked by engaging the engagement claw 15 with an engagement shaft 16 of the apparatus main body. Secure in closed position. Further, pressing springs 17 are arranged on the lower surface of the top cover 10 at positions corresponding to the corners of the upper surface of the developing device unit. By holding the top cover in a closed position, the pressing springs 17 are provided. The function of pressing and holding the developing device unit is performed through 17.

[0010] 2 arranged in the image forming section 8 of the apparatus main body
In one unit, the developing unit 30 is configured as shown in the plan view of FIG. 2 and the front view of FIG. A plurality of ribs are provided on the upper part of the main body frame of the developing unit 30 so as to protrude in parallel on the side surfaces in the upstream and downstream directions in the sheet transport direction, and the ribs reinforce the container portion and handle the unit. Are configured as handle members 31 and 31a for improving the performance. Support pins 38, 38a are provided on the side frames 37, 37a disposed on the side of the frame member so as to protrude outward, and the support pins are used as mounting means and positioning means for the image recording apparatus main body.

The developing unit 30 is located at the downstream side in the sheet conveying direction when the sheet is mounted on the image recording apparatus.
A pair of support plates 40 and 40a are provided integrally with the frame. The support plate can be made of an elastic material such as plastic, and is disposed so as to extend from the side frame 37 of the developing unit, and has a recess for accommodating a drum shaft of the photosensitive unit 60 described later. A groove and a hook member for locking and holding the mounted shaft and the like are provided. The support plate 40 has a tapered surface 43 having a vertical outer surface and an inclined inner surface. The upper portions of the pair of support plates have a wide upper part and a narrower lower part. Therefore, when mounting the photoconductor unit between the pair of support plates, without mounting the photoconductor unit horizontally,
It is configured so that the mounting operation can be performed easily.

In the developing unit 30 having the appearance shown in FIGS. 2 and 3, as shown in FIG. 1, an agitating member for supplying the toner to the supply roller 34 while agitating the toner inside the container portion 32. (Paddle member) 33 is arranged. Further, on the toner discharge side from the container portion 32,
A developing roller 35 in contact with the supply roller 34 and the photosensitive drum 65, and a layer thickness regulating member 36 in contact with the surface of the developing roller 35 are provided. The supply roller 34 can be configured as an elastic roller provided with a predetermined thickness of a sponge-like elastic body having conductive properties or a flocked body having conductive fibers. The supply roller 34 is connected to a supply member (not shown) via a shaft.
A bias voltage having a value of about 600 to -700 V, preferably about -650 V is applied.

The developing roller 35 comprises a metal roller shaft made of stainless steel or the like and a conductive rubber (silicone rubber, urethane rubber, NBR) coated with a predetermined thickness. The surface is configured to be smooth. For the developing roller 35, -300 to-
A bias voltage having a value of about 400 V, preferably about -350 V is applied. The layer thickness regulating member 36 disposed with respect to the developing roller 35 is for uniformly setting a thin layer of toner formed on the surface of the developing roller 35, and is a urethane resin sheet or a stainless steel plate member. It is configured as having spring properties. And, for the layer thickness regulating member 36, -600V to -700V.
A bias voltage in a range of V, preferably around -650 V is applied.

The distance between the axes of the supply roller 34 and the developing roller 35 is set to be slightly smaller than the sum of the radii of the two rollers, and by rotating both rollers in the same direction (the direction of arrow X). In the contact portion of the roller, the roller is slid in the opposite direction while being pressed. That is,
At a contact portion between the supply roller 34 and the developing roller 35,
Since both rollers slide in the pressure contact state, there is a large resistance in the sliding portion of the rollers. Therefore, the driving force for both rollers is larger than when two rollers are simply rotated without being pressed. It has the characteristic that it must be set to a value. In the developing unit, the toner is charged between the two rollers and the toner adheres to the surface of the developing roller 35 by the difference between the frictional action of the two rollers and the voltage applied to the two rollers. Then, the toner adhered to the surface of the developing roller 35 is formed as a thin layer having a uniform thickness by the layer thickness regulating member 36, and is exposed toward the photosensitive drum, thereby forming the electrostatic layer formed on the photosensitive drum. A toner image is formed by transferring the toner to the latent image.

The photosensitive unit 60 arranged in combination with the developing unit 30 includes a photosensitive drum 65,
A charging roller 67 such as a brush roller whose surface is formed by a flocking member or the like is arranged. Then, an image is written by a writing unit 70 disposed on the photosensitive drum 65, and the toner image formed on the photosensitive drum is transferred to a sheet by discharging the transfer roller 71. The writing unit 70 is composed of an LED head array, and emits an LED based on information from an image information output device to irradiate the photosensitive drum with light. The surface of the photosensitive drum 65 is made of a grounded photoconductor, and is charged to -750 V by a charging roller 67.
Is charged, the portion irradiated with light from the writing unit 70, that is, the potential of the portion of the image information with respect to black becomes about -50 V, and the portion irradiated with light and the non-irradiated portion (the portion corresponding to white of the image information) And a potential difference is generated, and an electrostatic latent image corresponding to the image information is formed.

When the toner adhering to the surface of the developing roller 35 comes into contact with the electrostatic latent image formed on the photosensitive drum in a state where the toner is charged to about -650 V, the toner is transferred to the photosensitive drum. It is sucked into the light irradiation site on the surface of 65,
A toner image is formed on the surface of the photosensitive drum (reversal development). At the toner image transfer position, the transfer roller 71 applies a bias voltage of 500 V to 2 kV from the back surface of the sheet, so that the toner image is transferred to the sheet. The sheet on which the toner image has been transferred is sent to a fixing device by the rotation of the photosensitive drum, and is fixed by applying a heating and pressing action. Further, after the toner image is transferred to the paper, the toner remaining on the surface of the photoconductor drum is disturbed by the charging roller 67 and dispersed on the surface of the photoconductor drum. It is charged to a potential. Then, at the position where the photosensitive drum contacts the developing roller 35, the residual toner is transferred to the developing roller 35 due to the potential difference between the two, and is mixed with the toner newly supplied from the container portion and reused.

In combination with the developing unit 30,
As shown in FIG. 1 and FIG. 5, which will be described later, the photoconductor unit 60 mounted on the image forming unit of the image recording apparatus has a side frame provided integrally with a main body frame 61 made of a plastic material. A metal drum shaft 66 is supported on the side frame via a bearing member, and a photosensitive drum 65 is provided on the drum shaft. Further, in addition to protruding the end of the drum shaft 66 outside the side frame, a pin member 63 is protruded at a predetermined interval above the drum shaft 66 to provide an image recording apparatus and a developing unit. Are configured as positioning means for. Further, a handle member 62 is provided on the upper part of the main body frame 61 so that the handle member 62 can be used as a handling member when the photoconductor unit is attached and detached.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, in order to mount two units on an image recording apparatus and perform mutual positioning of each unit, a sheet metal frame shown in FIG. 20 is arranged on the inner surface of the body frame. The sheet metal frame 20 is formed of a conductive metal plate, and includes a pin receiving groove 21 and a drum bearing groove 2.
2 and two concave grooves are provided so as to open upward. In addition, the main body output gear 23 is disposed on the unit mounting portion for transmitting drive to the developing unit 30. FIG. 5 shows a case where two units are combined and arranged on the sheet metal frame 20. First, the support pins 38 of the developing unit 30 are mounted in the pin receiving grooves 21 of the sheet metal frame 20. Thus, the developing unit 30 is positioned with respect to the image forming unit. In this state, the support plate 40 of the developing unit 30 is
Are overlapped with the drum bearing groove 22 of the sheet metal frame 20.

When the photosensitive unit 60 is mounted on the developing unit 30, the groove 4
1, the end of the drum shaft 66 protruding from the side of the photoconductor unit 60 is inserted, and the drum shaft 66 is positioned at the bottom of the two concave grooves 41 and 22. In this state, since the upper pin 63 disposed above the drum shaft 66 is positioned above the concave groove 41, the upper pin 63 is directed obliquely downward by the head of the hook member 42 having elasticity. To be pressed. In addition, the hook member,
Although it is possible to construct the hook member integrally with the support plate main body, it is also possible to use a means in which a hook member is formed using a material having high elasticity and is attached to the concave groove.
Then, the two projecting members 63 and 66 of the photoconductor unit
Is fixed to the concave groove 41 of the support plate 40 so as not to move, so that the photosensitive unit 60 is
It is mounted on the image recording apparatus main body in a state where it can be taken out integrally with the image recording apparatus.

In the present invention, by positioning the developing unit in the image forming section of the image recording apparatus, the driving of the developing unit with respect to the main body output gear 23 disposed on the sheet metal frame 20, as shown in FIG. The transmission gear 51 provided on the transmission portion is meshed. The drive transmission mechanism is configured to drive the stirring member 33, the supply roller 34, and the development roller 35 provided in the developing unit via the transmission gear 51 that meshes with the main body output gear 23.

After the developing unit 30 is positioned as described above, the end of the drum shaft 66 and the upper pin 63 are inserted into the concave groove 41 of the supporting plate 40 of the developing unit as shown in FIG. And the upper pin 63 is locked by the hook member 42. By mounting the photosensitive unit on the developing unit, the photosensitive drum 65 of the photosensitive unit is positioned with respect to the developing roller 35 of the developing unit. The positional relationship is set as shown in FIG. In the present invention, as shown in FIG. 7, the developing roller 3
The axis of the photosensitive drum is set at a lower position so that the axis b of No. 5 has a difference of the interval t1. The axis b of the developing roller 35 and the axis c of the supply roller 34 are equal to t2.
The height difference between the two rollers 3
When the rollers 4 and 35 slide, a large force is applied to a position lower than the axis b of the developing roller 35.

The photosensitive drum is arranged with respect to the developing roller.
Although it is provided in a state where it is pressed against by a weak force, a coating of an elastic body having a predetermined thickness is formed on the surface of the developing roller, so that the elastic body is slightly deformed at a contact portion between both rollers. State. Further, as shown in FIG. 7, the position of the axis of the photosensitive drum 65 is
By setting the photoconductor drum at a lower position with respect to the axis of the photoconductor drum, a force for constantly pressing the photoconductor drum downward is applied by the developing roller. When the photoconductor unit is mounted on the developing unit, a member protruding from the side of the photoconductor unit is mounted on a concave groove provided in the support plate of the developing unit from above, and the upper pin is hooked. It can be pressed by a member. Therefore, even if such a simple locking means is used, the contact portion between the photosensitive drum and the developing roller can exert an action of pressing the photosensitive unit downward, so that the photosensitive unit is There is no inconvenience such as floating. The height difference between the axis of the photosensitive drum and the axis of the developing roller can be set to an arbitrary value. The thickness is set in accordance with the conditions of the force of pressing the rotating members.

[0023]

As described above, in the present invention, the photoreceptor unit and the developing unit are constituted separately.
Since both units are provided with detachable means that can be separated from each other, they can be individually replaced according to the life of each unit. When processing paper jams or the like, the two units are integrated. It can be removed from the device body. Further, in the engagement state of the two units, the configuration is such that the axis of the photosensitive drum is positioned lower than the axis of the developing roller arranged in the developing unit, so that the position of the two rotating members is reduced. The relationship is set, and when the two rotating members are pressed against each other and are rotated in opposite directions, a downward force accompanying the rotation acts to suppress the lifting of the photoconductor unit, thereby preventing the two units from rising. Good mutual positional relationship can be maintained.

Further, a pair of support members are provided so as to protrude from the end of the developing unit to the photosensitive drum side, and a pair of a vertical drum shaft end provided on the side of the photosensitive unit and a pin member. Since the two projecting members are mounted in the engagement grooves provided in the support piece, the two units can be integrated in a predetermined positional relationship. In addition to the above effects, in the present invention, the engaging groove provided in the supporting member of the developing unit is provided with a locking member which is elastically deformed as the pin end of the drum shaft is inserted into and removed from the drum shaft. When the protruding member of the photoconductor unit is mounted in the concave groove of the support member of the developing unit, it can be pressed and held by the elastic member, and the mounting state can be visually checked.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of an image forming unit in which a developing unit and a photoreceptor unit to which the present invention is applicable are combined.

FIG. 2 is a plan view of a developing unit used in the present invention.

FIG. 3 is a front view of the developing unit shown in FIG. 2;

FIG. 4 is an explanatory diagram of a sheet metal frame arranged in the apparatus main body.

FIG. 5 is an explanatory diagram of a state where two units are combined via a sheet metal frame.

FIG. 6 is an explanatory diagram of a state in which a photoconductor unit is mounted on a developing unit.

FIG. 7 is an explanatory diagram of a positional relationship between a photosensitive drum and a shaft of a developing roller.

[Description of Signs] 1 Image recording apparatus, 2 Main body, 10 Top cover, 20 Sheet metal frame, 21 Pin receiving groove, 22 Drum bearing groove, 23 Main body output gear, 30 Developing unit, 34 Supply roller, 35 Developing roller, 38 support pins, 40
Support plate, 41 concave groove, 42 hook member, 5
0 drive transmission part, 51 conduction gear, 60 photoconductor unit, 63 upper pin, 65 photoconductor drum, 66 drum shaft, 67 charging roller, 70
Writing unit, 71 transfer roller.

Claims (3)

[Claims] 1. An image recording apparatus for forming a toner image on a photosensitive drum using an electrophotographic method and transferring the toner image to a sheet to form a copy, wherein a photosensitive unit and a developing unit are separated. In addition, both units are provided with detachable means that can be separated from each other, and when the two units are engaged, the axis of the photosensitive drum is
A process unit for an electrophotographic apparatus, wherein the process unit is configured to be located below a shaft center of a developing roller disposed in a developing unit. 2. A pair of support members are provided so as to protrude from the end of the developing unit toward the photoconductor drum, and the side of the photoconductor unit is formed of a drum shaft end and a pin member. The two projections are provided, and the two units are engaged by mounting a drum shaft end of a photoreceptor unit and a pin member in an engagement groove provided in the support piece. A process unit of the electrophotographic apparatus according to the above. 3. An engaging groove provided in a support member of the developing unit, wherein a locking member elastically deformed with insertion and removal of the drum shaft end and a pin member is provided. Or the process unit of the electrophotographic apparatus according to 2.