JPH10240001A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of accurately positioning an endless moving member and a counter member in a longitudinal direction by forming the butting parts of a photoreceptor drum and a developing roller in such tapered shape so that the diameter of one is made larger and the diameter of the other is made smaller toward outside in the longitudinal direction. SOLUTION: The butting parts 1a and 1b on a photoreceptor side in the tapered shape so that the diameter is made smaller toward the end in the longitudinal direction are formed on the surfaces of the vicinity of both ends in the longitudinal direction of the surface of the photoreceptor drum 1, and butting rollers 57a and 57b in the tapered shape so that the diameter is made larger toward the end are provided at both ends of the shaft part of the developing roller 51. When a 2nd developing unit is attached to a copying machine and the developing roller is pressed to the photoreceptor drum side, the butting roller butts against the butting part on the photoreceptor side, and the attaching position of the developing roller to the photoreceptor drum is restored to a desired position in the longitudinal direction.

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 copying machine, a facsimile, and a printer.
An endless moving member whose surface moves endlessly, an opposing member facing the surface of the endless moving member in a predetermined positional relationship, and at least one of the endless moving member and the opposing member is pressed against the other side with a predetermined pressing force. Pressing means for pressing; an endless moving member side abutting portion provided near both ends of the endless moving member in a width direction perpendicular to a surface moving direction of the endless moving member; and the width direction of the opposing member. An image in which the endless moving member-side abutting portion and the opposing member-side abutting portion come into contact with each other in a pressurized state by the pressing means. The present invention relates to a forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
The developer is carried in a thin layer on, for example, a developing roller as an opposing member, and is conveyed to a developing area, which is an opposing portion to, for example, a photosensitive drum as an endless moving member, and an electrostatic latent image on the photosensitive drum is Those that visualize are known. As described above, in the case where the developer carried on the developing roller is supplied to the electrostatic latent image on the photoconductor drum at the opposing position to visualize the electrostatic latent image, It is desired that the developer on the developing roller always faces the entire area where the above electrostatic latent image is formed.

For this reason, in a conventional image forming apparatus, the photosensitive drum and the developing roller are placed inside the image forming apparatus such that the developer on the developing roller faces the entire area where the latent image is formed on the photosensitive drum. And positioned and supported.

[0004]

However, in order to support the photosensitive drum and the developing roller inside the image forming apparatus, various parts are interposed, and the various parts have tolerances. The difference was getting bigger. For this reason, in the opposing portion between the photosensitive drum and the developing roller, the position where the developing roller opposes in the width direction of the latent image on the photosensitive drum, that is, in the longitudinal direction of the photosensitive drum, varies. If the position in the longitudinal direction fluctuates, the developer is not supplied to a part of the latent image area on the photoconductor, and there is a possibility that the image is missing without being developed.

Therefore, conventionally, the developer is carried on a developing roller so that the developer is reliably supplied to the entire latent image area on the photoreceptor even if the opposing position in the longitudinal direction varies. The variation is absorbed by giving a margin to the effective developing width of the developing roller, such as making the area longer in the longitudinal direction of the developing roller than the area of the latent image. However, in this method, the necessity of forming the developing roller longer by a margin arises, so that the size of the apparatus is increased.

[0006] The above-mentioned problem of the variation in the position between the photosensitive drum and the developing roller in the longitudinal direction and the problem of the enlargement of the apparatus due to consideration of the margin are not limited to the combination of the photosensitive drum and the developing roller. A combination with a belt-shaped latent image carrier or a developer carrier, or a combination of a latent image carrier and a charging roller or a transfer roller provided opposite to the latent image carrier, or a developing roller And an endless moving member whose surface moves endlessly, such as a combination of a drawing-up roller that draws up the developer to the developing roller, and a surface movement of the endless moving member, which is an opposing member provided opposite to the surface of the endless moving member. This can always occur between members that require positioning in the width direction perpendicular to the direction.

In particular, in an image forming apparatus which adopts a configuration in which a developer carrying member is housed in a developing device and the developing device is mounted on an image forming device main body in which a latent image carrying member is housed. Since there are many support members of various types such as a support portion between the developer carrier and the developing device, a support portion between the developing device and the image forming apparatus, the tolerance of each support member is small or large. And the deviation of the facing position of the developer carrier in the width direction of the electrostatic latent image on the latent image carrier tends to increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an endless moving member whose surface moves endlessly and a predetermined positional relationship with the surface of the endless moving member. An object of the present invention is to provide an image forming apparatus having an opposing member and capable of eliminating a displacement of the position of the opposing member in a width direction perpendicular to a surface moving direction of the endless moving member.

[0009]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: an endless moving member having a surface that moves endlessly; Opposing member, pressing means for pressing at least one of the endless moving member and the opposing member to the other side with a predetermined pressing force, and the endless moving member in a width direction perpendicular to a surface moving direction of the endless moving member. An endless moving member-side abutting portion provided near both ends of the moving member, and an opposing member-side abutting portion provided near both ends of the opposing member in the width direction; In the image forming apparatus in which the endless moving member-side abutting portion and the opposing member-side abutting portion come into contact in a pressurized state, the shape of the endless moving member-side abutting portion, and the shape of the opposing member-side abutting portion are ,on the other hand The abutting portion has a tapered shape in which the diameter decreases as going to the width direction end, and the other abutting portion has a taper shape in which the diameter increases as going to the width direction end, and the shapes are along each other. It is characterized by the following.

In the image forming apparatus according to the first aspect, each of the endless moving member is located near both ends in a width direction perpendicular to the endless moving direction and near the opposite ends in a direction corresponding to the width direction of the opposing member. An endless moving member-side abutting portion and an opposing member-side abutting portion are provided, and one of these abutting portions has a tapered shape in which the diameter decreases as approaching the width direction end, and The abutting portion is formed in a tapered shape corresponding to the tapered surface and increasing in diameter toward the end in the direction corresponding to the width direction, and the endless moving member side abutting portion and the opposing member side abutting portion are pressed by pressing means. The contact portion is pressed with a predetermined pressure. At this time, if the opposing member is offset to one side in the longitudinal direction with respect to the endless moving member,
A difference is generated in the pressure applied between the endless moving member-side abutting portion and the opposing member-side abutting portion on both sides in the longitudinal direction, and a force acts to balance the pressures at both ends.

FIG. 2 shows a photosensitive drum 1 as an endless moving member in which the surfaces at both ends in the longitudinal direction are tapered so that the diameter decreases toward both ends in the longitudinal direction. Butt roller 57 provided
This is an example in which a and 57b are formed in a tapered shape whose diameter increases toward both ends. FIG. 3 shows a state in which the developing roller 51 is shifted to the right in the longitudinal direction with respect to the photosensitive drum 1. As shown in this figure, when the developing roller 51 is pressed to the photosensitive drum 1 side by the force F in a state where the developing roller 51 is shifted to the right side with respect to the longitudinal direction of the photosensitive drum 1, the longitudinal direction of the developing roller 51 is changed. Butt roller 57a provided on the left side (hereinafter referred to as left side)
The contact roller 57b provided on the right side in the longitudinal direction of the developing roller 51 (hereinafter referred to as right side) contacts the portion of the photosensitive drum 1 where the diameter of the contact portion 1a is large. The portion 1b comes into contact with a small diameter portion. For this reason, the force Fa of the left abutting roller 57a pressing the abutting portion 1a of the photosensitive drum 1 is greater than the force Fa of the right abutting roller 57b pressing the abutting portion 1b of the photosensitive drum 1. And Fa> Fb. Further, when Fa and Fb are respectively divided into forces Fa ₁ and Fb _{1 in} a direction along the abutting surface of the photosensitive drum 1 and forces Fa ₂ and Fb ₂ in a direction perpendicular to the abutting surface, Fa ₁ > Fb It becomes ₁ . As a result, the developing roller 51 moves to the left in the longitudinal direction with respect to the photosensitive drum 1. Here, even if taking into account another component force Fa _2, Fb _2, thereby generating μFa _2, μFb ₂ is abutting portion 1 of the photosensitive drum 1
The friction coefficient μ between the surfaces a, 1b and the abutting rollers 57a, 57b can be ignored by reducing the friction coefficient μ. Then, when it moves to the position where Fa ₁ = Fb ₁ , both forces are balanced and stops without moving any more. Accordingly, even if the mounting position of the developing roller 51 with respect to the photosensitive drum 1 is shifted in the longitudinal direction, the developing roller 51 returns to a desired position.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the endless moving member is a latent image carrier for forming a latent image on the surface, and the facing member carries a developer on the surface. The developer carrying member is characterized in that the abutting portion on the latent image carrier side and the abutting portion on the developer carrying member side come into contact with each other in a pressurized state by the pressing of the pressing means.

In the image forming apparatus of the present invention, the vicinity of both ends of the latent image carrier in the latent image width direction on the latent image carrier and both ends of the developer carrier in the direction corresponding to the latent image width direction are provided. A latent image carrier-side abutting portion and a developer carrier-side abutting portion are respectively provided in the vicinity of the portion, and the diameter decreases as one of the abutting portions approaches the end portion in the latent image width direction. And the other abutting portion corresponds to the surface of the tapered shape, and has a tapered shape in which the diameter increases as it goes to the end portion in the direction corresponding to the latent image width direction. The carrier side contact portion and the latent image carrier side contact portion are pressed with a predetermined pressure. At this time, if the developer carrier is offset to one side in the longitudinal direction with respect to the latent image carrier, the developer carrier is applied between the latent image carrier side abutting portion and the developer carrier side abutting portion on both sides in the longitudinal direction. There is a difference in pressure, and a force acts to balance the pressure at both ends.

According to a third aspect of the present invention, in the image forming apparatus of the second aspect, the latent-image-bearing-side abutting portion or the developer-carrying-member-side abutting portion has a tapered shape when pressed by the pressing means. It is characterized by being driven in the circumferential direction.

In the image forming apparatus of the present invention, the tapered surface of the abutting portion on the latent image carrier side or the abutting portion on the developer carrier side is driven in the circumferential direction so as to abut the abutting portion of the latent image carrier. The other abutting portion or the abutting roller spirally moves on the tapered surface on the side driven in the circumferential direction at the contact portion with the abutting roller. Accordingly, the contact portion between the abutting portion of the latent image carrier and the abutting roller moves with a smaller force as compared with the movement along the axial direction.

According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect, the circumferential direction of the latent image carrier side abutting portion or the developer carrier side abutting portion in a state of being pressed by the pressing means. Is carried out when the developing device accommodating the developer carrying member is mounted on the image forming apparatus main body.

In the image forming apparatus according to the present invention, the developer carrier is housed in the developing device, and the developing device main body is mounted on the image forming apparatus main body housing the latent image carrier. When the developing device is mounted on the image forming apparatus main body, the latent image carrier-side abutting portion or the developer carrier-side abutting portion is driven in a circumferential direction in a state of being pressed by the pressing means, and the latent image is driven. The image carrier and the developer carrier are positioned in the longitudinal direction. Accordingly, even when the developer carrying member is easily attached to the main body of the image forming apparatus alone and the positional displacement in the longitudinal direction is likely to be large due to the large number of supporting members, the longitudinal direction caused by the attachment / detachment of the developing device is increased. Compensates for misalignment in the direction.

According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the third aspect, wherein the pressing by the pressing means is performed.
The driving of the abutting portion on the latent image carrier side or the abutting portion on the developer carrier side is used to visualize the latent image on the latent image carrier with the developer carried on the developer carrier. It is characterized in that it is performed in advance.

In the image forming apparatus according to the fifth aspect, before the latent image on the latent image carrier is visualized, the latent image carrier-side abutting portion and the developer carrier-side abutting portion are pressed while the latent image is pressed. The tapered surface of the carrier-side abutting portion or the developer-carrying-member-side abutting portion is driven in the circumferential direction, and the position of the latent image carrier and the developer carrier in the longitudinal direction is corrected to a desired position.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described using an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus.
The positioning of the latent image carrier as the endless moving member and the developer carrier as the opposing member in a predetermined positional relationship will be described. FIG. 1 is a front view showing a schematic configuration of a copying machine according to the present embodiment. First, an outline of the entire copying machine will be described. A photoconductor drum 1 as a latent image carrier having a diameter of 100 mm on which a photoconductor is formed is rotating clockwise in the drawing, and the surface of the photoconductor drum is connected to a first charger of a first latent image forming unit. 2 to charge. Then, the semiconductor laser of the optical writing device (not shown) is turned on according to the image signal of the first color portion sent from the image reading unit (not shown). The light L from the semiconductor laser is reflected by a polygon mirror (not shown) rotating at a predetermined rotation speed and is irradiated on the surface of the photosensitive drum 1, thereby forming a first electrostatic latent image on the surface of the photosensitive drum 1. Form. As a first developing device that develops the first electrostatic latent image, a first developing unit 3 that performs black development using a two-component developer obtained by mixing a black toner and a carrier is used.

The first developing unit 3 is provided with two developing rollers 31 so that a part thereof is exposed at an opening facing the photosensitive drum 1, and has a developing device 32 containing a two-component developer. And a toner hopper 33 containing toner to be supplied to the developing device. In the developing device 32, in addition to the developing roller 31, a paddle wheel 34 for supplying a developer to the developing roller 31 along a bottom in a developing device casing 32a, and a toner replenished from the toner hopper 33 are developed. A spheroid disk 35 for mixing and stirring with the developer in the container 32 and supplying the developer to the paddle wheel 34 is provided. In the toner hopper 33, a stirring member 36 that stirs the toner stored therein and sends the toner to a communication port side with the inside of the developing device 32 is rotatably provided.
The toner that has been scooped up from the lower portion of the toner hopper by the rotation of the stirring member 36 and passed to the communication port is
Is provided with a toner replenishing roller 37 for replenishing the toner. By the first developing unit 3 having the above configuration, the developing roller 31
Is used to develop the first electrostatic latent image on the photosensitive drum 1.

Next, the second charger 4 of the second latent image forming means
As a result, the surface of the photoconductor including the portion of the black toner image is -80.
Recharge to 0--900V. Then, the LED array of the optical writing device (not shown) is turned on in response to the image signal of the second color portion sent from the image reading unit, whereby the second electrostatic latent image is formed on the surface of the photosensitive drum 1. Form an image. The second electrostatic latent image is developed by a second developing unit 5 which is a second developing device, whereby toner images of a first color and a second color are formed on the surface of the photosensitive drum 1. You. The second developing unit 5 will be described later.

The two-color toner image on the photoreceptor 1 is collectively transferred on a transfer belt 6 provided with a transfer charger 6a or the like to transfer paper sent from a paper feed tray or a manual feed table (not shown). The image is fixed by a fixing roller of a fixing device (not shown), and the transfer paper is discharged onto a discharge tray (not shown). On the other hand, the surface of the photoconductor 1 after the transfer is cleaned by the cleaning device 7 to remove the remaining toner, and is prepared for the next image formation.

The second developing unit 5 is a developing device for performing development using toner as a non-magnetic one-component developer, and is provided so that a part thereof is exposed at an opening facing the photosensitive drum 1. A developing roller 51 as a developer carrying member;
A toner storage unit 52 for storing toner to be supplied to the developing roller 51; and a first storage unit 52 for stirring and transporting the toner in the toner storage unit.
An agitator 53, a second agitator 54, a toner supply roller 55 as a developer supply roller for holding the toner conveyed by the second agitator 54 on the downstream side in the developer conveyance direction and supplying the toner to the development roller 51; And a thinning blade 56 as a developer regulating member for equalizing the toner layer thickness on the roller 51. The toner supply roller 55 is provided with an elastic layer made of a porous elastic body on the surface.

In FIG. 2, the toner in the toner storage section 52 is stirred and transported by a first agitator 53 and a second agitator 54. Toner supply roller 55 holding toner sent out by second agitator 54
Supplies the toner held on the elastic layer to the developing roller 51 by rubbing with the developing roller 51, and the toner is given a triboelectric charge. Then, the thinning blade 56 is brought into contact with the developing roller 51 to make the toner layer thickness uniform, so that the toner on the developing roller 51 is equalized to an appropriate toner layer thickness. Conveyed to the area. In the developing area, the second electrostatic latent image on the photosensitive drum 1 is formed into a toner image by the developing roller 51. This second
The developing unit 5 is detachable from the copying machine main body.

FIG. 2 is an enlarged view of the vicinity of the opposing portion between the developing roller 51 and the photosensitive drum 1 according to the characteristic portion of the present embodiment. In this figure, the surfaces 1a and 1b near the both ends in the longitudinal direction of the surface of the photosensitive drum 1 are formed in a tapered shape whose diameter becomes smaller toward the end in the longitudinal direction. The photosensitive member side abutting portion 1a,
1b is formed. Further, abutting rollers 57 as tapered developer carrier-side abutting portions, whose diameters increase toward both ends, are provided at both ends of the developing roller 51.
a, 57b are provided at both ends. When the second developing unit 5 is mounted on the copying machine, the developing unit is pressed toward the copying machine by the force F. As a result, the developing roller 51 is pressed toward the photoconductor drum 1, and the photoconductor-side abutting portions 1 a and 1 b at both ends in the longitudinal direction of the surface of the photoconductor drum 1 are provided with abutting rollers provided on the shaft portion of the developing roller 51. 57a, 57b
Hits. Here, if the second developing unit is mounted so that the developing roller 51 is shifted to the right side in the longitudinal direction with respect to the photosensitive drum 1 as shown in FIG. While being deviated to the right with respect to the longitudinal direction of the drum 1, it is pressed against the photosensitive drum 1 by a force F. In this state, the abutting roller 57a provided on the left side in the longitudinal direction of the developing roller 51 contacts a portion where the diameter of the left photosensitive member side abutting portion 1a is large, and the abutting roller 57a provided on the right side in the longitudinal direction of the developing roller 51. Patch 5
7b is in contact with the portion where the diameter of the right photosensitive member side abutting portion 1b is small. For this reason, the force Fa of the left abutting roller 57a pressing the photosensitive member side abutting portion 1a is greater than the force Fb of the right abutting roller 57b pressing the photosensitive member side abutting portion 1b. Fa> Fb Becomes Further, Fa and Fb are respectively applied to forces Fa ₁ and Fb _{1 in} the direction along the surfaces of the photosensitive member side abutting portions 1 a and 1 b and the force F in the vertical direction.
When divided into a ₂ and Fb ₂ , Fa ₁ > Fb ₁ . As a result, the developing roller 51 moves to the left in the longitudinal direction with respect to the photosensitive drum 1 in order to make Fa ₁ and Fb ₁ equal on the left and right. When the developing roller 51 moves to the left to the position where Fa ₁ = Fb ₁ , the developing roller stops without moving any further. In a state where the forces are balanced, the photoconductor-side abutting portions 1a and 1b and the abutting rollers 57a are arranged such that the portion of the developing roller 51 carrying the developer just faces the latent image on the photosensitive drum 1. If the formation is performed in consideration of the shape, the mounting position, and the like of 57b, as shown in FIG. Needless to say, the positioning of the developing roller 51 in the longitudinal direction with respect to the photosensitive drum 1 is performed so that the gap between the surface of the developing roller 51 and the surface of the photosensitive drum 1 is uniformly maintained in the longitudinal direction. Photoreceptor side abutting part 1
It is also necessary to consider the shapes of a, 1b and butting rollers 57a, 57b.

Further, by pressing the photosensitive member side contact portions 1a, 1b and the contact rollers 57a, 57b, the photosensitive member side contact portions 1a, 1b and the contact rollers 57a, 57b are kept in contact with each other in the axial direction. In order to move smoothly, it is desirable to reduce the other component forces Fa ₂ and Fb ₂ . For this reason, it is conceivable to reduce the friction coefficient μ between the photosensitive member side abutting portions 1a and 1b and the abutting rollers 57a and 57b so that μFa ₂ and μFb ₂ are negligibly small. As a material for reducing the friction coefficient, for example, the surface of the photosensitive drum 1 is aluminum,
Polyacetal, polycarbonate, polybutylene terephthalate, or the like may be used as a material for forming the butting rollers 57a and 57b. All of these have a small coefficient of friction with respect to aluminum.

With the above configuration, even if the mounting position of the developing roller 51 with respect to the photosensitive drum 1 is shifted in the longitudinal direction,
It can always be returned to a desired position, and the widthwise end of the latent image on the photosensitive drum 1 will not be developed, and there will be no image defects such as missing images. Further, since it is not necessary to provide a margin for the effective developing width of the developing roller 51 assuming the positional variation in the longitudinal direction, the width of the latent image on the photosensitive drum 1 and the width of the developing roller 51 for carrying the toner are determined. The length of the developing roller 51 can be reduced as compared with the case where a margin is provided, and the size and cost of the apparatus can be reduced.

FIG. 4 is an enlarged view of the vicinity of the opposing portion of the photosensitive drum 1 and the developing roller 51 according to a modification of the present embodiment.
In this modification, the shapes of the photosensitive member side abutting portions 1a and 1b and the abutting rollers 57a and 57b of the shaft portion of the developing roller 51 are different from the example shown in FIG.
The diameters of a and 1b are increased toward the end in the longitudinal direction, and the diameters of the abutting rollers 57a and 57b are reduced toward the end of the shaft of the developing roller 51.

As in the above modified example, the photosensitive member side abutting portion 1
a, 1b and the abutting rollers 57a, 57b, even if the taper shape of the abutting rollers 57a, 57b is changed.
By pressing to the side, the positioning of the developing roller 51 and the photosensitive drum 1 in the longitudinal direction can be performed.

Next, in the configuration of FIG. 2 and FIG.
The displacement between the developing roller 51 and the photosensitive drum 1 in the longitudinal direction can be corrected more smoothly. To this end, the photosensitive drum 1 may be driven to rotate while the second developing unit is pressed against the photosensitive drum 1 body. When the photoconductor drum 1 is rotated, the photoconductor-side abutting surface also rotates. When the abutting rollers 57a, 57b are pressed against the rotating photosensitive member side abutting portions 1a, 1b, the abutting rollers 57a, 57b roll around the photosensitive member side abutting portions 1a, 1b, and stop the photosensitive drum. The developing roller 51 can be moved in the longitudinal direction with respect to the photosensitive drum 1 with a weaker force than pressing in the state.
As described above, the displacement between the developing roller 51 and the photosensitive drum 1 in the longitudinal direction can be more reliably corrected, and the positioning in the longitudinal direction can be performed more accurately.

The pressing of the developing roller 51 toward the photosensitive drum 1 and the rotational driving of the photosensitive drum 1 are simultaneously performed after the second developing unit 5 is mounted on the copying machine main body. The development may be performed before the development.
As in the case of the second developing unit 5, which adopts a configuration in which the developing roller 51 is held in the unit and the entire unit is held in the copying machine body, the developing roller 5
Since there are many support members, the positional deviation in the longitudinal direction tends to increase due to the accumulation of the tolerances of the members.
For this reason, when the second developing unit 5 is mounted on the copying machine main body, a deviation in the longitudinal direction between the photosensitive drum 1 and the developing roller 51 easily occurs. The developing roller 5 is attached to the end of the latent image on the body drum 1.
On the other hand, there is a portion where the developer is not supplied, the image is spilled, and if the developing roller 51 is lengthened by a margin in order to prevent the image spilling, the apparatus may be increased in size or cost may be increased. Such attachment and detachment of the second developing unit is necessary every time toner is consumed in a configuration in which the second developing unit is detached from the copying machine main body and remounted to supply toner or the like. That is. If the above-described correction of the longitudinal displacement is always performed after the second developing unit 5 is mounted, the longitudinal position between the photosensitive drum 1 and the developing roller 51 is always maintained in a desired positional relationship. The development can be performed with the desired positional relationship between the photosensitive drum 1 and the developing roller 51 in the longitudinal direction at any time.

Further, it is also possible to constitute so as to always correct the longitudinal displacement before developing. With this configuration, a desired positional relationship between the photosensitive drum 1 and the developing roller 51 in the longitudinal direction at the time of development can be obtained more reliably.

In the above, the structure for accurately positioning the photosensitive drum 1 as the endless moving member and the developing roller 51 as the opposing member in the longitudinal direction has been described. The present invention is not limited to the positioning between the photosensitive drum and the developing roller. For example, the present invention can also be applied to the positioning of the charging roller of the first charger 2 provided between the photosensitive drum and the photosensitive drum 1, and between the developing roller, 51, the toner supply roller 55, and the like. .

[0035]

According to the image forming apparatus of the present invention, there is provided an image forming apparatus having an endless moving member whose surface moves endlessly and an opposing member which faces the surface of the endless moving member in a predetermined positional relationship. There is an excellent effect that the displacement of the position of the facing member in the width direction perpendicular to the surface moving direction of the endless moving member can be eliminated. In addition, since it is not necessary to provide a margin for the endless moving member and the facing member assuming a positional shift in the width direction, the size of the endless moving member and the facing member in the width direction can be set to a minimum, There is also an excellent effect that the size and cost of the device can be reduced as compared with the case where the margin is provided.

According to the image forming apparatus of the second aspect, there is an excellent effect that the positioning of the latent image carrier and the developer carrier in the longitudinal direction can be accurately performed. In addition, since there is no need to provide a margin for the effective development width of the developer carrying member, assuming the above-described variation in the position in the longitudinal direction, the latent image width of the latent image carrying member and the developer on the developer carrying member are not supported. The width of the developing device can be made equal, and the length of the developer carrying member in the developing width direction can be shortened as compared with providing a margin.

In particular, according to the image forming apparatus of the third aspect,
Since the contact portion between the abutting portion of the latent image carrier and the abutting roller moves with a smaller force than moving along the axial direction, the longitudinal direction between the latent image carrier and the developer carrier is Has an excellent effect that the position can be easily corrected, and the positional relationship can be made more accurate.

According to the image forming apparatus of the present invention, the developer carrier is housed in the developing device, and the developing device main body is mounted on the image forming apparatus main body side in which the latent image carrier is housed. In an image forming apparatus in which the latent image carrier and the developer carrier are likely to be displaced in the longitudinal direction due to the adoption, in the longitudinal direction between the latent image carrier and the developer carrier after the developing device is mounted. There is an excellent effect that positioning can be accurately performed. In addition, even when the detachment of the developing device from the image forming apparatus is repeatedly performed for replenishment of the developer or the like, the above-described longitudinal displacement can be corrected each time the developing device is detached. There is also.

According to the image forming apparatus of the fifth aspect,
When the latent image on the latent image carrier is visualized, the positioning of the latent image carrier and the developer carrier in the longitudinal direction is always performed accurately. Image can be prevented from appearing at the end of the image due to
There is an excellent effect that a stable image can always be output.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a copying machine according to an embodiment.

FIG. 2 is an enlarged view of the vicinity of a facing portion between a developing roller and a photosensitive drum according to a characteristic portion of the embodiment.

FIG. 3 is a diagram illustrating a state in which a developing roller is shifted to the right in a longitudinal direction with respect to a photosensitive drum.

FIG. 4 is an enlarged view of the vicinity of an opposing portion between a photosensitive drum and a developing roller according to a modification of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 1a, 1b Photoconductor side abutting part 2 1st charger 3 1st developing unit 4 2nd charger 5 2nd developing unit 6 Transfer charger 7 Cleaning device 51 Developing rollers 57a, 57b Abutting roller

Claims (5)

[Claims] An endless moving member whose surface moves endlessly, an opposing member facing the surface of the endless moving member in a predetermined positional relationship, and at least one of the endless moving member and the opposing member is placed on the other side. A pressing means for pressing with a predetermined pressing force; an endless moving member side abutting portion provided near both ends of the endless moving member in a width direction perpendicular to a surface moving direction of the endless moving member; An opposing member-side abutting portion provided near both ends in the width direction of the member, and the endless moving member-side abutting portion and the opposing member-side abutting portion are pressed by the pressing means. In the image forming apparatus contacting in a state, the shape of the endless moving member-side abutting portion, and the shape of the opposing member-side abutting portion are tapered such that the diameter decreases as one of the abutting portions approaches the end in the width direction. From An image forming apparatus having a tapered shape in which the diameter increases as the other abutting portion approaches the end in the width direction, and has a shape along each other. 2. The image forming apparatus according to claim 1, wherein the endless moving member is a latent image carrier for forming a latent image on a surface, and the facing member is a developer carrier for carrying a developer on the surface. An image forming apparatus characterized in that the pressing portion of the latent image carrier and the pressing portion of the developer carrier come into contact with each other in a pressurized state by a pressing means. 3. The image forming apparatus according to claim 2, wherein the abutting portion on the latent image carrier side or the abutting portion on the developer carrier side is driven in a tapered circumferential direction in a state of being pressed by the pressing means. Image forming apparatus. 4. The image forming apparatus according to claim 3, wherein the pressing of the latent image carrier side abutting portion or the developer carrier side abutting portion in the circumferential direction in the pressed state by the pressing means is performed by the developer carrier. The image forming apparatus is mounted when the developing device accommodating the image forming apparatus is mounted on the image forming apparatus main body. 5. The image forming apparatus according to claim 3, wherein the pressing by the pressing means and the driving of the latent image carrier side abutting portion or the developer carrier side abutting portion are carried by the developer carrying member. An image forming apparatus which performs the visualization before the latent image on the latent image carrier is visualized with the developer.