JPS6017775A - Developing device - Google Patents

Abstract

PURPOSE:To execute satisfactorily development regardless of an error at some extent in the size accuracy and the assembling position of each part for constituting a developing device by always positioning exactly a position control roller at a desired position. CONSTITUTION:A bearing 28 is made to control uniformly with a pair of rollers 44 by the force of a spring, and always positioned securely at a position corresponding to the middle of these rollers 44. The pair of rollers 44 are placed symmetrically at a part corresponding to the middle of two developing rolls 21, therefore, each interval of a position control roller 27 and two developing rolls 21 becomes the same for both intervals. Therefore, each interval of a photosensitive body 4 and two developing rolls 21 becomes the same for both intervals as well. As a result, each interval of the photosensitive body 4 and two developing rolls 21 is kept constant for both interval. One position controller 27 is used against two developing rolls 21 to keep constant each interval of the photosensitive body 4 and two developing rolls 21 for both interval. Accordingly, even if the number of developing rolls 21 increases, half or so of the number of the position control rollers 27, will do.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a developing device in an electronic copying machine.

[Prior art]

Some electronic copying machines use a belt-shaped photoreceptor to create a copy image through charging, exposure, development, transfer, and fixing steps.

FIG. 1 shows an example of such a conventional electronic copying machine.

In this electronic copying machine, a belt-shaped photoreceptor 4 is wound around a driving roller 1 and two driven rollers 2.3. When the driving roller 1 rotates and the photoreceptor 4 travels in the direction of the arrow, the surface of the photoreceptor 4 is first charged by the charger 5 . When the charged surface of the photoreceptor 4 passes a predetermined position, an exposure device (not shown) performs image exposure as indicated by an arrow B, and an electrostatic latent image is formed on the surface of the photoreceptor 4. The electrostatic latent image is developed with toner particles at a location facing the developing device 6, forming a toner image.

On the other hand, the paper 7 sent out from the paper cassette is conveyed as indicated by arrow C by a conveyance device, also not shown, and is superimposed on the toner image formed on the photoreceptor 4. The toner image on the photoreceptor 4 is transferred onto the stacked sheets 7 by the action of the transfer device 80. The paper 7 after the transfer is peeled off from the photoreceptor 4 by the action of the static eliminator 9.
After being sent to a fixing device (not shown) and fixed, it is discharged to a discharge tray (also not shown). The toner image remaining on the surface of the photoreceptor 4 is neutralized by a static eliminator 10 and then cleaned by a cleaning device 11.

2 and 3 show a part of the developing device 6 of this electronic copying machine.

This developing device 6 performs development using a magnetic plan development method. In such a developing method, it is necessary to maintain a constant distance between the developing roll 21 for forming a magnetic brush and the photoreceptor 4. For this reason, this developing device 6 is designed with such a design.

The main body 22 of the developing device 60 is provided on the surface side of the photoreceptor 4. A support plate 23 is attached to the developing device main body 22 with screws 24 . Support plate 2
3, a developing roll 21 is rotatably supported via a bearing 25. A protrusion 26 is formed at a predetermined location corresponding to the developing roll 21 at the upper end of the support plate 22 .

A position regulating roller 27 is provided at a predetermined location facing the developing roll 21 on the back side of the photoreceptor 4 . The position regulating roller 27 is connected to the support plate 2 via a bearing 28.
9 is rotatably supported. A portion of the bearing 28 protrudes below the support plate 29. Support plate 2
9 is attached via a pin 30 to a long hole 32 formed in the side plate 31 so as to be vertically movable. The support plate 29 is urged downward by the force of the spring 33, and is positioned at a position where the bearing 28 comes into contact with the protrusion 26 of the support plate 22. As a result, the position regulating roller 27 is brought into pressure contact with the back surface of the photoreceptor 4, and the distance between the photoreceptor 4 and the developing roll 21 is kept constant.

By the way, in such a developing device, the bearing 28 is attached to the protrusion 26.
By simply making contact with the position regulating roller 27
is being positioned. Therefore, in such a developing device, the position of the position regulating roller 27 is influenced by the dimensional accuracy of each component and the error in the assembly position.

If the position regulating roller 27 is misaligned, the distance between the photoreceptor 4 and the developing roll 21 will change, and the relative angle of the photoreceptor 4 to the developing roll 21 will also change, which will adversely affect image quality. For this reason, such a conventional developing device requires high accuracy in the dimensions and assembly positions of each of its component parts, which has been an obstacle in efforts to reduce costs.

Further, some of such developing devices use a plurality of developing rolls 21 in order to improve the developing efficiency and increase the copying speed. In such a developing device, the number of protrusions 26 corresponding to the number of developing rolls 21 is provided, and the number of position regulating rollers 27 corresponding to the number of protrusions 26 is provided.

Therefore, in such a developing device, as the number of developing rolls 210 increases, the weight increases, the load on the photoreceptor traveling system increases, and the cost also increases.

Another conventional electronic copying machine uses a position regulating plate 35 instead of a position regulating roller, as shown in FIG. However, in such an electronic copying machine, the photoreceptor 4 rubs against the position regulating plate 35, which increases the load on the photoreceptor traveling system, and the photoreceptor 4 is easily worn out, shortening its lifespan. Put it away.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides a developing device that can always reliably position a position regulating roller for regulating the position of a belt-shaped photoreceptor at a desired position. The purpose is to

[Structure of the invention]

In the present invention, the support portion +
A pair of rollers are provided at g, and the shaft portion of the position regulating roller for regulating the position of the belt-shaped photoreceptor is brought into contact with these rollers, thereby positioning the position regulating roller at the desired position. This is what I did.

〔Example〕

The present invention will be described in detail below with reference to Examples.

5 and 6 show the main parts of a developing device in an embodiment of the present invention. In these figures, parts having the same names as those in FIGS. 2 and 3 are given the same reference numerals, and their explanations will be omitted as appropriate.

In this developing device, two
Another support plate 41 is attached to a predetermined location corresponding to the middle of the two developing rolls 21 with screws 42 . The upper part of the support plate 41 projects above the support plate 23.

A pair of shafts 43 are symmetrically provided on the upper part of the support plate 41. Rollers 44 are fitted onto these shafts 43, respectively. Bearings 28 provided on the position regulating rollers 27 are mounted on these rollers 44 . Bearing 2
Although not shown, the support plate 29 supporting 8 is attached via a pin to a long hole in the side plate so as to be vertically movable, and is biased downward by the force of a spring, as in the conventional case. .

Therefore, in this developing device, the bearing 28 is evenly pressed against the pair of rollers 44 by the force of the spring.
It is always reliably positioned at a position corresponding to the middle of 4. Since the pair of rollers 44 are symmetrically arranged at locations corresponding to the middle of the two developing rolls 21, the distances between the position regulating roller 27 and the two developing rolls 21 are the same. For this reason, the photoconductor 4 and the two developing rolls 2
1 and the respective intervals are also the same. As a result, the distances between the photoreceptor 4 and the two developing rolls 21 are kept constant.

In this developing device, one position regulating roller 27 is used for two developing rolls 21, and the distances between the photoreceptor 4 and the two developing rolls 21 are kept constant. Therefore, even if the number of developing rolls 21 increases, the number of position regulating rollers 27 may be about half that number. Therefore, even if the number of developing rolls 21 increases, the increase in weight is reduced, the load on the photoreceptor traveling system is also reduced, and furthermore, the increase in cost is also reduced.

In the above embodiment, one position regulating roller 27 is used for two developing rolls 21, but it goes without saying that the number of these rollers may be the same.

Further, although the bearing 28 is used in the above embodiment, the pair of rollers 44 may be made rotatable without using this, and the shaft of the position regulating roller 27 may be placed directly on these.

〔Effect of the invention〕

As explained above, according to the present invention, the position regulating roller can always be reliably positioned at the desired position.
Even if there is a certain degree of error in the dimensional accuracy and assembly position of each component constituting the developing device, development can be performed satisfactorily. Therefore, an electronic copying machine with stable quality can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a schematic front view showing an example of a conventional electronic copying machine, Fig. 2 is a front view showing a part of the developing device of the same copying machine, and Fig. 3 is a longitudinal section taken along line III-III in Fig. 2. Side view, 4th
The figure is a schematic front view showing a part of another conventional electronic copying machine, FIG. 5 is a front view showing main parts of a developing device in an embodiment of the present invention, and FIG. FIG. 4... Belt-shaped photoreceptor, 6... Developing device, 21... Developing roll, 23... Support plate, 27... Position regulating roller, 29...Support plate, 41...Support plate, 44...Colo. Applicant Fuji Serotox Co., Ltd. Representative Umeo Yamauchi Patent Attorney 1 Figure 11 2 Figure 4 Figure 2 Figure 3

Claims (1)

[Claims] In an electronic copying machine that uses a belt-shaped photoreceptor, develops an electrostatic latent image formed on the surface with toner particles, and transfers the resulting toner image onto paper to create a copy image, the photoreceptor is a developing roll rotatably provided on the surface side of the photoreceptor for supplying toner particles to the surface by magnetic brush development; a supporting member rotatably supporting the developing roll; a position regulating roller rotatably provided on the back side and in contact with the back surface to regulate the position of the photoreceptor relative to the developing roll; and a position regulating roller provided on the developing roll support member and in contact with the shaft of the position regulating roller. A developing device comprising a pair of rollers that regulate the position of the rollers.