JPH08248714A - Image forming device - Google Patents

Abstract

PURPOSE: To reduce the weight of the front and rear side plates, which are relatively thick and heavy, while maintaining their rigidity, in the image forming device where the front and rear side plates are connected with stays and a drive unit is attached to the side plate. CONSTITUTION: The side plates 20 and 21, front and back, are connected by a fixing lower-stay 23, a fixing upper-stay 24, an optical stay 25, and a bottom plate 22. The mounting flange 30a of the drive unit 30 overlaps the fixing stay 23 and optical stay 25. The mount flange 30a is pressed against the rear side plate 21, and small screws 30b are passed through the flange 30a and rear side plate 21 and firmly screwed into the fixing lower-stay 23 and optical stay 25. Thus, because the rectangular, rigid drive unit 30 is firmly attached to the fixing stay 23 and optical stay 25 via the rear side plate 21, the strength and rigidity of the rear side plate 21 are increased by the drive unit 30 even though the rear side plate 21 is thin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art There is a multicolor electrophotographic copying machine as an example of such an image forming apparatus. In this multicolor electrophotographic apparatus, since the apparatus main body is relatively large, its housing is fastened with two metal plates (hereinafter referred to as front side plate and rear side plate) and a plurality of metal stays between the metal plates. The configuration is generally. Further, in particular, in the color image forming apparatus, it is ideal that mechanical vibration (motor etc.) and impact are suppressed to be as small as possible due to its image forming method, and it is required that the housing has high rigidity.

[0003]

The present invention is a further development of the above-mentioned prior art.

An object of the present invention is to provide an image forming apparatus which can achieve both weight reduction and rigidity increase.

[0005]

According to a first aspect of the present invention, a casing is formed by fastening separated side plates via a plurality of stays, and a member for forming an image by the casing, and these members. In the image forming apparatus that supports the driving means of the member, the driving means is fastened to a plurality of stays via the side plates.

A second invention of the present invention is the image forming apparatus according to the first invention, characterized in that the side plate has a guide member for guiding the driving means to a position where it is mounted on the side plate.

According to a third aspect of the present invention, the image forming apparatus according to the first aspect is characterized in that the drive means has a guide member, and the guide member projects beyond the output portion of the drive means. Is.

A fourth invention of the present invention is the image forming apparatus according to the second or third invention, wherein the guide member is provided with a locking member for locking the driving means.

[0009]

【Example】

(First Embodiment) An embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. 1. FIG. 1 is an explanatory diagram of the overall configuration of a full-color laser beam printer which is an image forming apparatus.

First, the overall structure of this image forming apparatus will be briefly described. As shown in FIG. 7, this apparatus conveys a recording medium P by a conveying means 1 and winds it around a transfer drum 2a constituting a transfer means 2. In synchronism with this, a light image is emitted from the scanner unit 3 to the photosensitive drum 4a, which is an image carrier in the image carrier unit 4, to form a latent image, and the developing unit 5 is operated to perform development corresponding to each color. Agent (hereinafter "toner")
Image) is formed on the recording medium P.
The recording medium P after the transfer of the toner images onto the recording medium P after the toner image transfer is conveyed to the fixing unit 6 to fix the toner, and the recording medium P is discharged to the discharging unit 7.

Next, the structure of each part of the image forming apparatus will be sequentially described in detail.

(Conveying Means) The conveying means is the paper feed cassette 1a.
The recording mediums P that are stacked and stored in the recording medium P are conveyed.
The sheet is fed one by one by means of the guide plate 1d and the conveying roller pair 1e to the registration roller pair 1f, and the registration roller pair 1f conveys it to the transfer drum 2a at the same timing.

The recording medium P after transfer is separated from the transfer drum 2a by a separating member 1g and is guided to a fixing means 6 by a guide plate 1h, and the recording medium P after fixing is discharged by a discharge roller pair 1i. It is discharged to 7.

(Transfer Means) The transfer means is the photosensitive drum 4
The toner image formed on a is transferred to the recording medium P, and in this embodiment, the transfer drum 2 rotating in the direction of arrow a.
The recording medium P is wound around a and the toners of the respective colors are superposed and transferred onto the recording medium P.

The transfer drum 2a has a dielectric layer on the outermost periphery and can be rotated about a shaft 2b by a motor (not shown). A gripper 2c is provided at a predetermined position on the outer circumference, and the gripper 2c is used for the registration roller pair 1
The tip of the recording medium P conveyed by f is gripped.

An electrostatic attraction roller 2d is provided near the outer periphery of the transfer drum 2a so that it can be brought into contact with and separated from the drum 2a, and the recording medium P is sandwiched between the electrostatic attraction roller 2d and the transfer drum 2a. Is pressed against the outer periphery of the transfer drum 2a, and the electrostatic attraction roller 2d and the transfer drum 2a
By applying a voltage between them, electric charges are induced in the recording medium P which is a dielectric and the dielectric layer of the transfer drum 2a, and the recording medium P is electrostatically attracted to the outer periphery of the transfer drum 2a. .

When the recording medium P supported by the transfer drum 2a comes into contact with the photosensitive drum 4a, the photosensitive drum 4a
A transfer charger 2e for transferring a toner image by applying a voltage having a polarity opposite to that of the toner image is provided.

The method of attracting the recording medium P to the transfer drum 2a is not limited to the electrostatic attraction, but may be a suction method using air or the like.

(Scanner Unit) The scanner unit 3 scans the light from the laser diode 3a, which emits light in accordance with an image signal, with the rotating polygon mirror 3b, and scans it onto the photosensitive drum 4a via the lens 3c and the reflection mirror 3d. A light image corresponding to each color is emitted.

(Image bearing unit) Image bearing unit 4
Is a photosensitive drum 4a and a part of the image forming means arranged around the photosensitive drum 4a. In this embodiment, the primary charging means 4b and the cleaning means 4c are incorporated in a case to form a unit. .

The photoconductor drum 4a has an organic photoconductive layer formed on the outer peripheral surface of an aluminum cylinder, and rotates in the direction of the arrow in FIG. 7 during image formation.

In this embodiment, the photosensitive drum is illustrated as the image bearing member, but the image bearing member is not limited to this, and includes, for example, the following. First, a photoconductive layer is used as the photoconductor, and examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and the above-mentioned organic photoconductor (OPC). The shape on which the photoconductor is mounted includes, for example, a drum-shaped, belt-shaped rotating body, a sheet-shaped body, and the like. Generally, a drum-shaped or belt-shaped member is used. For example, in a drum-type photosensitive member,
As described above, the photoconductor is applied or vapor-deposited in the shape of a cylinder of aluminum alloy or the like.

The primary charging means 4b uses a so-called contact charging method, and a conductive roller is brought into contact with the photosensitive drum 4a, and a voltage is applied to the conductive roller to cause the surface of the photosensitive drum 4a. Is uniformly charged.

The cleaning means 4c is for cleaning the toner remaining on the photosensitive drum 4a after the toner image formed on the photosensitive drum 4a by the developing means, which will be described later, is transferred to the recording medium P. A cleaning blade 4cl for scraping off the residual toner on the photosensitive drum 4a and a conveying screw 4 for scraping off the scraped toner.
It is conveyed to the waste toner container by c2, and when the waste toner container is full, the waste toner container is removed and replaced.

The image carrier unit 4 is provided with guide ridges 4d on its case in the front and back directions of the paper surface of FIG. 1, and the ridges 4d are provided on the apparatus main body 8 in the front and back direction of the paper surface of FIG. The guide rail 4e is provided so as to be slidable, and can be detachably attached to the apparatus main body 8 from the front side of the paper surface of FIG. 7, and can be replaced according to the life of the photosensitive drum 4a.

(Developing Unit) The developing unit 5 develops the latent image formed on the photosensitive drum 4a with toners of respective colors of magenta, cyan, yellow and black to visualize the latent image. Developing means (magenta developing means 5M, cyan developing means 5C, yellow developing means 5Y, black developing means 5B) for developing
have.

The four developing means 5Y, 5M, 5C, 5
B is a developing device 5Y, 5M, 5C, 5B in order of the photosensitive drum 4 according to the image forming operation by the rotating mechanism.
It is rotatable so as to face a. That is, the developing means 5Y, 5M, 5C and 5B are arranged so that they can be indexed and rotated at an angle of 90 degrees about the rotary shaft 5a, and the centers of the developing means 5M, 5C, 5Y and 5B are of revolution gears not shown. It is configured to rotate in association with a rotation gear arranged on the outer circumference, and its posture is always kept constant. And the respective developing means 5Y, 5M, 5C,
5B has a toner container 5b, a coating roller 5c, a developing roller 5d, a developing blade 5e, and the like.

When forming an image, magenta, cyan,
Developing means 5 corresponding to each color development of yellow and black
Y, 5M, 5C and 5B rotate around the shaft 5a, one of the developing means 5Y, 5M, 5C and 5B stops at the position facing the photoconductor drum 4a, and the developing roller 5d moves to the photoconductor drum 4a. The toner image is formed on the photoconductor drum 4a after being positioned so as to face the photoconductor drum 4a with a minute gap (about 300 μm). That is, each developing means 5Y, 5M, 5C, 5B sends the toner in the toner container 5b corresponding to the color to be developed to the applying roller 5c by the sending mechanism and rotates the applying roller 5c.
Further, a toner layer is formed on the outer circumference of the developing roller 5d which is rotated by the blade 5e, and an electric charge is applied to the toner (friction charging). By applying a developing bias between the developing roller 5d and the photosensitive drum 4a on which the latent image is formed, toner development is performed on the photosensitive drum 4a according to the latent image.

Toner is replenished to the toner container 5b by the cylindrical toner cartridge 5 in the toner container 5b.
A mounting portion to which the f is detachable is provided, and the toner cartridge 5f can be mounted to the mounting portion by inserting the toner cartridge 5f from the front side to the back side in FIG.

The toner cartridge 5f has a cylindrical shape having a center parallel to the rotary shaft 5a of the developing unit 5, has a slot opening in the generatrix direction, and has a color corresponding to the color of each developing means inside. The toner is stored, and a seal is attached to the opening and folded back. This toner cartridge 5f
With the opening facing downward into the mounting portion of the toner container 5b,
The folded seal is opened by pulling the toner, the toner is dropped into the toner container 5b, and then half-turned to be fixed to the toner container 5b by a cam lock (not shown).

When the toner is replenished, the developing means 5Y, 5M,
When 5C and 5B are sequentially rotated 90 degrees about the rotation shaft 5a, the cartridge mounting portions are sequentially replaced, and the toner cartridge 5f can be pulled out in the axial direction at a fixed position.

(Fixing Means) The fixing means 6 is for fixing the toner transferred onto the recording medium P. As shown in FIG. 7, the driving roller 6a is driven and rotated, and the recording medium P is pressed against the driving roller 6a. The fixing roller 6b applies heat and pressure. That is, the recording medium P separated from the transfer drum 2a
Is transported by the drive roller 6a when passing through the fixing means 6, and heat and pressure are applied by the fixing roller 6b. As a result, the unfixed toner transferred to the recording medium P is fixed.

A cleaning member 6c is in contact with the fixing roller 6b, and the toner attached to the fixing roller 6b is removed by the cleaning member 6c, and at the same time, an offset preventive agent is applied.

FIG. 1 is a perspective view showing the structure of the first embodiment. As shown in the figure, the housing of the apparatus main body 8 is the front plate 2
The bottom plate 22, the lower fixing stay 23, the upper fixing stay 24, and the optical stay 25 are fastened together between 0 and the rear side plate 21.

On the other hand, the drive unit 30 which is a drive unit supported by the casing is a fixing unit 6 which is a unit.
The image carrier unit 4, the developing unit 5, the transfer unit 2 and the like are provided with a motor and a gear train. The drive unit 30 has a cubic box shape and is provided with a mounting flange 30 a on the side to be mounted on the rear side plate 21. Therefore, the drive unit 30 alone has high rigidity.

In the conventional example, the drive unit 30 is supported and fixed to the rear side plate 21 and is not fixed to the stays, but in the present invention, the drive unit 30 has the mounting flange 30a, as shown in FIG. A small screw 30b for inserting the rear side plate 21 is attached to the lower fixing stay 23 and the optical stay 2.
5 is directly screwed and fastened to the bent end portions 23a and 25a. By this fastening, the drive unit 30 itself becomes the rear side plate 2.
Since it is reinforced with 1 and is joined to each stay as a temporary rear side plate, high rigidity can be secured, and the rear side plate 2
It is possible to reduce the plate thickness of No. 1 and achieve weight reduction and cost reduction.

Next, a method of attaching the drive unit 30 to the rear side plate 21 of the present invention will be described.

The drive unit 30 is composed of a motor and a gear train, as described above. Matama drive unit 30
A gear train 33 and a coupling 32 for giving each power are formed on the side surface of the. Drive unit 30
At the time of mounting, the gear train 33 and the coupling 32 are inserted into the holes 26 provided in the rear side plate 21, and the drive unit 30
Are supported and fixed to the rear side plate 21. The coupling 32 of the drive unit 30 moves the photoconductor drum 4a of the image carrier, and the gear 33 gives power to the transfer means 2 and the fixing means 6, and the coupling 32 and the gear 33 are provided.
Are used with extremely high precision. Therefore, it is necessary to avoid giving an impact or the like to the coupling 32 and the gear 33 for image formation.

According to the conventional mounting method, the assembling worker supports the drive unit 30 while the hole 2 provided in the rear side plate 21.
6, it is necessary to work with care so that the coupling 32 and the gear 33 do not hit the end of the hole 26, and the working time tends to be long, but in the present invention, as shown in FIG. At the inside of the rear side plate 21, a mounting portion 27b
And a guide member 27 fixed by a machine screw 34. The guide portion 27 a of the guide member 27 is the rear side plate 21.
And projects toward the outer horizontal direction of the rear side plate 21. The guide portion 27a is rod-shaped, and the hole 30c into which the guide portion 27a slides is attached to the mounting flange 3 of the drive unit 30.
It is provided at 0a. The guide member 27 guides the drive unit 30 and moves the drive unit 30 horizontally so that the coupling 32 and the gear 33 can be easily set to a predetermined position on the rear side plate 21 without being damaged. Has become. The length L1 of the guide member 27 must be longer than the height L2 of the coupling 32 gear 33.

(Second Embodiment) FIGS. 3 and 4 show a second embodiment.

In contrast to the construction in which the guide member is provided on the rear side plate in the first embodiment, the drive unit 30 is provided with the guide member 31 and the rear side plate 21 is provided with a hole 21a into which the guide member 31 slides. are doing. By adopting this configuration, the mountability of the drive unit 30 to the rear side plate 21 is further excellent in the following points while maintaining the same level.

As described above, the drive unit 30 uses the highly accurate coupling 32 and the gear 33. Before being actually attached to the rear side plate 21, there is a state in which the drive unit 30 alone is temporarily placed. At this time, it is naturally conceivable that the drive unit 30 falls down on the floor FL as shown in FIG.

If it falls, the coupling 3 as shown in FIG.
2. It is expected that eccentricity or the like will occur on the gear 33 due to scratches or impacts, which will cause a problem.

Therefore, in the second embodiment, the guide member 31 is provided.
Even if the drive unit 30 is supported by the flange 30a and falls down, the coupling 32 and the gear 33 are provided with a function as a protection member so as not to be directly impacted.

(Third Embodiment) FIGS. 5 and 6 show a third embodiment.

In the first embodiment, the structure of the guide member for safely setting the drive unit to the predetermined position is shown. However, as a method of actual work, that is, a method of fastening the drive unit to the rear side plate 21 and each stay, a small screw is used. The conclusion has been made.

In the third embodiment, the guide member 27 has a slope 2
Protrusions 28 having 8a and a vertical surface 28b are provided.

The hole 3 is provided so that it can go over the protrusion 28.
0c is a long hole. When the long hole 30c is inserted into the guide member 27 and propelled, the long hole 30c goes over the protrusion 28, and the flange 30a of the drive unit 30 is housed inside the protrusion 28. When the hand is released here, the center of gravity M of the drive unit 30 causes a moment to move the drive unit 30 away from the rear plate 21, so that the assembling operator must constantly press the drive unit against the rear plate. By providing the protrusion 28 on the guide member 27, it is possible to easily perform the screw tightening work without operating the protrusion 28, and the assembling time is shortened.

[0049]

As described above, according to the present invention,
According to the first aspect of the present invention, the rigidity of the housing is secured by fastening the plurality of stays and the driving means, so that it is possible to reduce the weight and cost of the device.

In the second aspect of the present invention, in the first aspect of the present invention, by providing the side plate with the guide member, it is possible to improve the assembling property of the driving means to the side plate.

According to a third aspect of the present invention, in the first aspect, the drive means is provided with a guide member, and the guide member projects from the output portion of the drive means, so that the assembling ability of the drive means to the side plate is improved. In addition, the output unit is protected from coming into contact with the place where the output unit is placed when handling the drive unit.

According to the fourth aspect of the present invention, in the second or third aspect, the guide member is provided with the engaging portion for engaging the driving means, so that the assembling property is further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a side view showing the first embodiment of the present invention.

FIG. 3 is a side view showing a second embodiment of the present invention.

FIG. 4 is a side view showing the operation of the second embodiment of the present invention.

FIG. 5 is a side view showing a third embodiment of the present invention.

FIG. 6 is a side view showing the operation of FIG.

FIG. 7 is a vertical sectional view of the image forming apparatus.

[Explanation of symbols]

 21 Rear Side Plate 23 Lower Fixing Stay 25 Optical Stay 27, 31 Guide Member 28 Projection Part 30 Drive Unit 32 Coupling 33 Gear

Claims (4)

[Claims] 1. An image forming apparatus in which a housing is formed by fastening separated side plates via a plurality of stays, and the housing supports members for image formation and driving means for these members. An image forming apparatus, wherein the driving means is fastened to a plurality of stays via the side plate. 2. The image forming apparatus according to claim 1, wherein the side plate has a guide member for guiding the driving means to a position where the driving unit is attached to the side plate. 3. The image forming apparatus according to claim 1, wherein the drive unit has a guide member, and the guide member projects from the output portion of the drive unit. 4. The image forming apparatus according to claim 2, wherein the guide member is provided with a locking member that locks the driving means.