JPH08152781A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device capable of forming an image while keeping the interval between developing rollers and a photoreceptor constan without requiring special adjustment, and short in assembling time, simple in structure and low in cost. CONSTITUTION: The image forming device carries out the image formation by sticking toner while making at least two or more developing rollers 1 opposed to the photoreceptor 3 with a specific interval. The image forming device is provided with a support member 4 which freely rotatably supports the end 1c of the developing rollers 1 so that the interval between the developing rollers 1 pivotally supported by a developing device 2 and the photoreceptor 3 is kept equal, and a developing device support member 5 made of an elastic material and supporting the developing device 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an image forming apparatus such as a copying machine, a facsimile, a printer, a scanner, or a multi-functional machine having these functions together.
The present invention relates to an image forming apparatus including a developing device that supplies toner in a state in which a plurality of developing rollers are opposed to a surface of a photoconductor with a predetermined gap.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
An electrostatic latent image is formed by irradiating image information such as reflected light from a document on a photoconductor uniformly charged in advance, and toner is supplied from the developing device to the electrostatic latent image. By transferring and fixing the toner image on the recording paper,
An image is being formed. In an image forming unit of a conventional image forming apparatus, it is necessary to surely position and hold two developing rollers of a developing device opposed to a surface of a photosensitive member with a predetermined gap to adhere toner. Since it was difficult to obtain a stable and high quality formed image, the mechanism for positioning and holding the two developing rollers is an extremely important element.

By the way, in order to secure a predetermined gap between the two developing rollers as magnet rollers constituting the developing device and the photoconductor, the gap between the one developing roller and the photoconductor is adjusted and adjusted. , When adjusting the gap between the other developing roller and the photoconductor, the case and the frame are connected by the fine adjusting means by rotating the developing device as a center around the axis of the one developing roller that has been positioned and adjusted first. However, an electrophotographic copying machine in which adjustment is performed by rotating operation is known (Japanese Patent Laid-Open No. 63-9).
See the publication of 8674). However, if the above-mentioned adjustment process is interposed in the manufacturing process of the image forming apparatus as in this conventional example, there arises a problem that the assembly time increases and the structure becomes complicated, resulting in high cost. It was

FIG. 5 is a perspective view showing an example of a conventional developing device and a photoconductor positioning mechanism. From the side surface of the developing device 102, shafts 101a and 101b of a developing roller (not shown) are shown.
2 are projected and are respectively supported by the long holes 104a and the supporting portions 104b provided in the supporting member 104. In this positioning mechanism, in order to make the gap between the two developing roller shafts 101a and 101b of the developing device 102 and the photoconductor 103 equidistant without adjustment, the photoconductor 103 and the two developing units are Roller shafts 101a and 101b are flat plate supporting members 1
04, and an elongated hole 104a having an arc shape such that the gap with the outer peripheral surface of the photoconductor 103 is equidistant is provided at an appropriate position of the supporting member 104, and one shaft 101a is inserted into the elongated hole 104a. Good.

However, the other developing roller shaft 1 is attached to the supporting portion 104b which receives most of the weight of the developing device 102.
01b is inserted, and the load of the developing device 102 is applied to the supporting portion 10.
4b is concentrated on the support portion and is likely to be deformed. When the entire developing device is rotated as described above, the support portion 104
Since the supporting portion of b is the reference, if the supporting portion 104b is deformed, the two developing rollers 101 and the photosensitive member 103 are
There is a problem that the gap between and is not equidistant and deformation or displacement occurs.

[0006]

In the above-mentioned conventional image forming apparatus, in order to secure a gap between two or more developing rollers equipped in the developing device and the photosensitive member, one developing roller and the photosensitive member are provided. After adjusting the gap with the body, the gap between the other developing roller and the photoconductor was adjusted.
Assembling time increases and the structure becomes complicated, resulting in high cost, or the load due to the weight of the developing device concentrates on the supporting portion of the supporting member of the developing roller, causing deformation and misalignment. There is a problem that the distance from the body is not equidistant and the image quality is affected.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention is to solve such a problem. That is, it is an object of the present invention to provide an image forming apparatus which can hold an interval between a developing roller and a photoconductor at an equal distance to form an image without adjustment, and which can be assembled in a short time, has a simple structure, and is inexpensive. And

[0008]

In order to achieve the above object, the present invention according to claim 1 is characterized in that at least two or more developing rollers are opposed to the surface of the photoconductor with a predetermined gap therebetween. In an image forming apparatus equipped with a developing device for adhering toner from the developing roller to the surface of a photoconductor to perform development, a gap between the photoconductor and each of the developing rollers pivotally supported by the developing device is equal. It is characterized in that it has a supporting member for rotatably supporting each shaft end portion of the developing roller so as to have a distance, and a developing device supporting member made of an elastic material for supporting the developing device. The invention according to claim 2 is characterized in that the developing device supporting member is provided on a vertical line of the center of gravity of the developing device. Claim 3
In the invention described above, the developing device support member is configured to guide the developing device in the attachment / detachment direction at the time of attachment / detachment.

[0009]

The image forming apparatus having the above structure is
According to a first aspect of the present invention, the developing roller is rotatably supported so that the developing roller, which is supported by the developing device supporting member made of an elastic material, is rotatably supported by the developing device, and the photosensitive member has the same distance. Since the load on the supporting member due to the weight of the developing device is reduced by supporting the developing device by the support, the gap between the developing roller and the photosensitive member surface can be adjusted even if the gap between the photosensitive member surface and the developing roller is not adjusted. It is possible to provide an image forming apparatus which holds images at equal distances, forms an image, has a short assembly time, has a simple structure, and is inexpensive.

According to a second aspect of the present invention, the gap between the developing roller and the photosensitive member, which are supported by the developing device supported by the developing device supporting member made of an elastic material on the vertical line at the center of gravity, are equidistant. Since the developing roller is rotatably supported by the supporting member to reduce the load on the supporting member of the developing device, the gap between the surface of the photoconductor and the developing roller can be adjusted without any adjustment. It is possible to provide an image forming apparatus that holds an equidistant distance from the surface of the body to form an image, has a short assembly time, has a simple structure, and is inexpensive.

According to another aspect of the present invention, the distance between the developing roller and the photosensitive member, which is supported by the developing device supporting member made of an elastic material and is axially supported by the developing device which is guided in the attaching / detaching direction at the time of attaching / detaching, is equidistant. Since the developing roller is rotatably supported by the supporting member to reduce the load on the supporting member of the developing device, the developing roller can be adjusted without adjusting the gap between the surface of the photoconductor and the developing roller. It is possible to provide an image forming apparatus in which the gap between the surface of the photoconductor and the surface of the photoconductor is held at an equal distance to form an image, the assembly time is short, the structure is simple, and the cost is low.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is an explanatory view of a main configuration of an electrophotographic image forming apparatus to which the present invention is applied. Reference numeral 1 (1a, 1b) is a developing roller for supplying toner onto a photoconductor, and 2 is a developing roller 1. The developing device 3, the photoconductor drum 4 (4a,
4b) is a supporting member, 5 is a developing device supporting member, 6 is a charger, 7 is exposing means, 8 is a paper feed tray, 9 is a paper feed roller,
10 is a registration roller, 11 is a transfer paper, 12 is a transfer device, 13 is a cleaning device, 14 is a paddle roller, 1
5 is a stirring roller, 16 is a separator, 17 is a conveying screw, 18 is a doctor blade, 19 is a toner hopper, and 20 is a lower guide rail. By turning on the image formation start button of the operation unit (not shown), the surface 3a of the drum-shaped photoconductor 3 rotating in the direction of arrow A shown in the drawing.
Is uniformly charged by the charger 6, and is scanned and exposed by the laser beam of the exposure unit 7 to form an electrostatic latent image based on the image information obtained by a reading unit (not shown).

The electrostatic latent image formed on the surface 3a of the photoconductor 3 has a developing device 2 having a two-component developer (not shown) therein.
It is developed with the toner supplied from, and becomes a toner image. The toner image formed on the surface 3a of the photoconductor 3 is fed through the paper feed tray 8, the paper feed roller 9, and the registration roller 10,
It is transferred by the transfer device 12 onto the transferred transfer paper 11. After the transfer is completed, the transfer paper 11 has a toner image fixed by a fixing device (not shown) and is discharged onto a discharge tray or the like (not shown). Further, the residual toner remaining on the surface 3 a of the photoconductor 3 without being transferred onto the transfer paper 11 is removed by the cleaning device 13.

The developing device 2 has an opening 2a in its casing, and two developing rollers 1a and 1b are arranged in the opening 2a in a vertical positional relationship. That is, the developing roller 1 located above in the casing of the developing device 2
a, a developing roller 1b located below, and a paddle roller 14 for stirring and conveying a two-component developer (not shown) inside
A stirring roller 15, a separator 16 and a conveying screw 17 for agitating the two-component developer (not shown) in the longitudinal direction, and the one developing roller 1a of the developing roller 1.
The developing device 2 includes a doctor blade 18 for equalizing the amount of the two-component developer (not shown) and a toner hopper 19 for supplying toner (not shown). The developing device 2 is provided on the side of the main body of the image forming apparatus. Guided by the side guide rail 20, it is detachable in the vertical direction of the paper surface and inserted.

After that, each end (shaft) 1c of the developing roller 1 is rotatably supported so that the gap between the developing roller 1a on one side and the developing roller 1b on the other side and the photoconductor 3 is equidistant. 4 (fixed to the image forming apparatus side) supports the developing roller 1 with respect to the surface 3 a of the photoconductor 3.
The positional relationship between a and 1b is determined. At that time, the developing device 2
Is supported at its lower portion by a developing device supporting member 5 made of an elastic material and attached to the lower guide rail 20. The developing device supporting member 5 is provided on the vertical line of the center of gravity of the developing device 2. That is, the developing device supporting member 5 is arranged on the lower surface of the developing device at a position immediately below the center of gravity.

It should be noted that the rotation axis of the photoconductor 3 and the rotary shaft 2 of the photoconductor 3 are adjusted so that the gap between the two developing rollers 1a of the developing device 2 and the surface 3a of the photoconductor 3 with respect to the developing roller 1b becomes equal without adjustment.
The rotary shafts of the book developing rollers 1a and 1b are both supported on the same plane of the supporting member 4, and the supporting member 4
A circular arc-shaped long hole 4a is provided at one position so that the gap with the surface 3a of the photosensitive member 3 is equidistant, and the shaft 1c of the upper developing roller 1a is supported by the long hole 4a. One developing roller 1a of the developing roller 1 and the other developing roller 1b
Both rotate in the opposite direction (clockwise direction) to the drum-shaped photoconductor 3 that rotates in the direction of arrow A in the figure.

FIG. 2 is a perspective view showing an example of the structure of the developing device supporting member. The developing device supporting member 5 is a leaf spring 5a on the lower guide rail 20 and of the developing device 2 not shown. The developing device 2 is mounted on the vertical line of the center of gravity and is designed to lift and support the developing device 2 (not shown) in the upward direction shown by the arrow B in the drawing. The load on the holes 4b) will be reduced.

FIG. 3 is a structural explanatory view of a developing device having a developing device supporting member of another embodiment of the present invention, and FIG. 4 is an enlarged view of another embodiment of the developing device supporting member. In this embodiment, the developing device supporting member 5 is located above the developing device and is fixed to the image forming device side. The developing device supporting member 5 supports the slide portion 2b projectingly provided on the upper part of the developing device so as to be movable back and forth in a direction orthogonal to the paper surface. The developing device supporting member 5 is composed of a main body 5a fixed to the image forming apparatus side and a guide member 5b fixed to the lower portion of the main body 5a. The guide member 5b is made of an elastic material such as a metal leaf spring, rubber or resin. When guiding the slide portion 2b integrated with the developing device 2 in the attachment / detachment direction perpendicular to the paper surface, the developing device 2 is lifted and supported in the direction of arrow C shown in the drawing. The load of the load on the support member 4 is reduced. Therefore, the gap between the developing roller 1a and the other developing roller 1b with respect to the surface 3a of the photoconductor 3 is equal to the gap between the developing roller 1a and the surface 3a of the photoconductor 3 with respect to the developing roller 1b without any special adjustment. It is possible to provide an image forming apparatus that holds an image at a distance and performs image formation, has a short assembly time, has a simple structure, and is inexpensive.

[0019]

As described above, according to the present invention, in the developing roller rotatably supported by the developing device supported by the developing device supporting member made of an elastic material,
Since each developing roller is rotatably supported by the supporting member so that the distance to the surface of the photosensitive member is equal, the load on the supporting member of the developing device is reduced. The gap between the developing roller and the developing roller can be kept constant without any special adjustment, and the image quality is maintained by holding the gap between the developing roller and the surface of the photoconductor at an equal distance. In addition, the assembly time can be shortened, the structure can be simplified, and the cost can be reduced.

According to the second aspect of the present invention, the developing device supporting member made of an elastic material is disposed on the vertical line of the center of gravity of the developing device, and the developing roller is supported by the developing device. Since the developing roller is rotatably supported by the supporting member so that the gap between the photosensitive member and the photosensitive member is equidistant, the load on the supporting member of the developing device is reduced, so no special adjustment is required. In addition, the gap between the developing roller and the surface of the photoconductor is kept equidistant to form an image, and the assembly time is shortened to simplify the structure and further reduce the cost.

According to the third aspect of the invention, the gap between the developing roller, which is supported by the developing device supporting member made of an elastic material, and which is guided in the attaching / detaching direction at the time of attachment / detachment, is equidistant from the developing roller. Since the developing roller is rotatably supported by the supporting member so as to reduce the load on the supporting member of the developing device, the surface of the developing roller and the surface of the photosensitive member can be adjusted without any special adjustment. It is possible to reduce the assembly time by shortening the assembling time and simplifying the structure while performing the image formation while keeping the gaps between and at the same distance.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating an outline of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view illustrating a main part of the image forming apparatus according to the embodiment of FIG.

FIG. 3 is an explanatory diagram illustrating an outline of an image forming apparatus according to another embodiment of the present invention.

FIG. 4 is an enlarged perspective view illustrating a main part of the image forming apparatus according to the embodiment of FIG.

FIG. 5 is a perspective view illustrating a main part of a conventional image forming apparatus.

[Explanation of symbols]

1 ... Developing roller, 1a ... One developing roller, 1
b ... other developing roller, 1c ... end portion, 2 ...
Developing device, 2a ... Opening part, 2b ... Sliding part,
3 ... Photoconductor, 3a ... Surface, 4 ... Support member, 4a ... Oblong hole support member, 4b ... Support member, 5
... Developing device support member, 5a ... Leaf spring, 5b ...
.Guiding members, 6 ... charger, 7 ... exposure means, 8 ...
..Paper feed tray, 9 ... paper feed roller, 10 ... registration roller, 11 ... transfer paper, 12 ... transfer device,
13 ... Cleaning device, 14 ... Paddle roller, 15 ... Agitation roller, 16 ... Separator, 1
7 ... Transport screw, 18 ... Doctor blade,
19 ... Toner hopper, 20 ... Lower guide rail, 101 ... Developing roller, 101a ... One developing roller, 101b ... Other developing roller, 101c
... edge part, 102 ... developing device, 102a ... opening part, 102b ... slide part, 103 ... photoconductor, 103a ... surface, 104 ... supporting member, 1
04a ... long hole support member, 104b ... support member.

Claims (3)

[Claims] 1. A developing device for performing development by causing at least two or more developing rollers to face a surface of a photoconductor with a predetermined gap therebetween so that toner is adhered from the developing roller to the surface of the photoconductor. An image forming apparatus including: a support for rotatably supporting each shaft end portion of the developing roller so that a gap between the developing roller whose shaft is supported by the developing device and the photoconductor is equidistant. An image forming apparatus comprising: a member; and a developing device supporting member made of an elastic material that supports the developing device. 2. The image forming apparatus according to claim 1, wherein the developing device supporting member is provided on a vertical line of a center of gravity of the developing device. 3. The image forming apparatus according to claim 1, wherein the developing device support member has a structure that guides the developing device in an attaching / detaching direction at the time of attachment / detachment. The image forming apparatus described.