JPH0460656A - Image forming device - Google Patents

Abstract

PURPOSE:To easily and accurately position developing devices by holding a photosensitive body and plural developing devices by respective holding means and providing each developing device with a developing device position control means which positions the developing device to a guide means which guides the photosensitive body. CONSTITUTION:A circulatable photosensitive body 1 like an endless belt, a photosensitive body holding means 6 1A which holds the photosensitive body 1, plural developing devices 31Y, 31M,31C, and 31K, a single developing device holding means 71 which holds plural developing devices 31Y to 31K, and a guide means 9 which is placed on the opposite side to developing devices 31Y to 31K of the photosensitive body 1 and guides the photosensitive body 1 are provided. Each of developing devices 31Y to 31K is provided with a developing device position control means 55 which is brought into contact with the guide means 9 to position the developing device to the guide means 9. Thus, positional relations between the photosensitive body 1 and a developer carrying means are accurately and easily set to always obtain a satisfactory visible image, and assembling is facilitated as well.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an image forming apparatus, and for example, to an image forming apparatus that forms a multicolor image using an electrophotographic method.

In the prior art, image formation by electrophotography is performed as follows. A pre-charged photoreceptor is imagewise exposed to form an electrostatic latent image on the surface of the photoreceptor due to the difference in surface potential between a light-receiving area and a non-light-receiving area. The latent image is reversely developed to form a visible image on the surface of the photoreceptor, and this visible image is transferred to recording paper and further fixed.

A rotatable drum-shaped photoconductor is widely used as a photoconductor, and around this drum-shaped photoconductor there are a charging device, an image exposure device, a developing device, a transfer device, a static eliminator, and an excess developer component ( Various devices are provided, such as cleaning devices, for removing toner (toner) from the photoreceptor. Then, while the drum-shaped photoreceptor rotates, an image is formed on the recording paper through the above process.

By the way, there is a request to reduce the vertical dimension of the image forming device and make it flat, but since many types of devices are arranged around the photoreceptor as mentioned above, it is difficult to meet this request. There are limits to what we can respond to.

In particular, in a full-color image forming device, the developing device is
At least three developing devices are required for the three primary colors cyan, yellow, and magenta, and in order to make black clearer, an additional developing device for black must be installed, making it difficult to meet the above requirements. It is. In addition, with a rotating drum photoreceptor, in order to form an image on a large-sized recording paper such as A3 size, the diameter of the photoreceptor must be increased accordingly.
The image forming device has no choice but to become larger.

On the other hand, if an endless belt-like photoreceptor that is rotated around a pair of pulleys is used in a horizontal position, it is easy to meet the above requirements, and it is also possible to form images on large-sized recording paper. This also has the advantage that the size of the image forming apparatus can be increased only slightly.

Particularly in a full-color image forming apparatus having three or four developing devices, it is preferable to arrange the developing devices so as to face the horizontal portion of the endless belt-like photoreceptor.

Incidentally, the developing device is provided with a rotatable developing sleeve that serves as a developer conveying means for supplying developer from a developer reservoir to the photoreceptor, and the developing sleeve is spaced apart from the photoreceptor by a predetermined minute distance. It is well located. If this minute interval is not accurate, development will not be carried out well and the resulting image will not be good either. When using an endless belt-like photoreceptor, unlike when using a drum-like photoreceptor, it is difficult to position the developing sleeve so as to accurately maintain the above-mentioned minute intervals.

OBJECT OF THE INVENTION The present invention provides an image forming apparatus in which the positional relationship between an endless belt-like photoreceptor and a developer conveying means can be accurately and easily set, a good visible image can always be obtained, and it is easy to assemble. It is intended to.

29. Structure of the Invention The present invention provides a rotatable endless belt-like photoreceptor, photoreceptor holding means for holding the photoreceptor, a plurality of developing devices, and a single developing device that holds the plurality of developing devices. and a guide means (for example, a platen 9 described later) located on the opposite side of the photoreceptor from the developing device, the guide means being in contact with the guide means to guide the photoreceptor. The present invention relates to an image forming apparatus in which each of the developing devices is provided with a developing device position regulating means for positioning the developing device relative to the developing device.

E, Example The present invention will be explained in detail below.

Embodiment 1 FIG. 5 is a schematic front view of the interior of a multicolor image forming apparatus using one type of digital copying.

In this example, as shown in an enlarged view in FIG. 11, an endless belt-shaped photoreceptor 1 is used, which has a photosensitive layer 1b adhered to the surface of an endless belt-shaped base 1a. Endless held photoconductor (hereinafter simply referred to as "photoconductor J")
It is called. ) 1 is a driving pulley 2A and a driven pulley 2B
It is hung on the roof and can be circled like an arrow. A platen 9 is located within the photoreceptor 1 so that the photoreceptor 1 is positioned in an accurate positional relationship with each part described later.

Below the photoreceptor 1, 3 scorotron band electrodes, 4 developing units 31Y, 31M, 31C131K, a transfer pole 4, and a separation pole 5 are arranged. The photoreceptor 1 is grounded via a conductive brush 7 that is in sliding contact with a conductive coating layer (not shown) provided on the side edge of the photoreceptor 1 .

The recording paper P is brought into close contact with the lower surface of the photoreceptor 1 by a roller 10 under the drive pulley 2A. That is, the platen 9 functions as a guide for accurately moving the photoreceptor 1 and the recording paper P.

According to this device, in the image reading unit LE, the original 18 placed on the original platen 19 receives light from the illumination light source 13 moving in the X direction, and the reflected light 20 is reflected by the mirror 14, the lens 15, and the color separation Images are formed on the 17th through the filter 16 on each CCD image sensor 17R117G for red, green, and blue. These CCD image sensors convert optical information into time-series electrical signals and send them to an image data processing unit TR (see Figure 6).
Here, recorded image data of yellow, magenta, cyan, and black are formed. In the laser optical system 11, the laser beam of the semiconductor laser 21 is modulated in the modulation section MD based on the yellow recorded image data from the video signal processing section TR2 (in the figure, 22 is a polygon mirror). On the other hand, the surface of the rotating photoreceptor 1 is uniformly charged by the scorotron charge electrode 3. Subsequently, the photoreceptor 1 is irradiated with imagewise exposure light from the laser optical system 11 . In this way, an electrostatic latent image is formed. This electrostatic latent image is reversely developed by a developing device 31Y containing yellow toner.

The photoreceptor 1 on which the toner image has been formed is uniformly charged again by the scorotron charging electrode 3, and then subjected to image exposure based on, for example, the read magenta optical information. The formed electrostatic latent image is transferred to a developing device 31M containing magenta toner.
Reversal development is performed. As a result, a two-color toner image of yellow toner and magenta toner is formed on the photoreceptor 1. Thereafter, in the same manner, cyan toner and black toner are superimposed and reversely developed in the developing device 31C131K, and the photoreceptor 1
A four-color toner image is formed thereon. The four-color toner image is transferred at once onto the recording paper P at the transfer pole 4 by being charged with a pre-transfer charging electrode as required. Recording paper P is separated from photoreceptor 1 by separation pole 5 and fixed by fixing device 6 . On the other hand, the photoreceptor 1 is cleaned by a cleaning blade 8A and a sponge roller 8B.

Although a four-color toner image has been described above, a three-color toner image other than black, a two-color toner image, or a single-color toner image may be formed depending on the case.

According to FIG. 6, the control unit CT is actuated by the operation unit OP, and the image reading unit LE whose operation is controlled by the control unit converts the optical information of the document 18 into time-series signals for each color.
After A/D conversion, the obtained data is sent to the image data processing unit TR.
, and is further subjected to D/A conversion in a video signal processing section TR to convert it into a pulse width modulated or intensity modulated signal suitable for recording. The image forming section RE executes the above-described process for forming an image based on the control signal, transfers a toner image onto copy paper, and forms a recorded matter. This image forming section RE
adopted an electrophotographic method.

In addition to the above, various preset information, especially data on functional operation contents such as the copy magnification and color described above, can be stored in the ROM (Re
The information stored in the image memory ME can be stored in the image memory MH such as a floppy disk or a magnetic tape, and the information in the image memory ME can be taken out and output to the image forming section RE as necessary.

Figure 7 is a plan view of the developing device, Figure 8 is a front view, and Figure 9 is a front view.
The figure is the same right side view, and Figure 10 is the same left side view.
FIG. 1 is an enlarged sectional view taken along the line XI-XI in FIG.

Developer reservoirs 43A and 43B partitioned by a partition plate 49 within the chassis 50 are provided with screws 46 and 47, respectively, in parallel to each other. The developing sleeve 41 is located at a position that is closer to the screw 47 by an interval indicated by d2 in FIG. 11 from above a line that bisects the line segment connecting the centers of the screws 46 and 47. This positional relationship is intended to provide a margin for mounting the scraper 45 shown in FIG. 11 and to allow the sleeve 41 to mainly transport the developer in the developer reservoir 43A.

A spur gear 53 is attached to the outside of the chassis side wall 50a, and rotates by meshing with a spur gear attached to the shaft of a motor (not shown). The spur gear 53 includes the spur gear 4 attached to the shaft 46a of the screw 46.
6b meshes. The developing sleeve 41 is attached to the spur gear 46b.
A spur gear 41b attached to the shaft 41a of the screw 47 meshes with a spur gear 47b attached to the shaft 47a of the screw 47. Thus, in FIG. 9, the rotation of the spur gear 53 in the direction of the arrow causes the spur gears 46b, 47b, and 41b to rotate in the direction of the arrow, respectively.

The developer is supplied from the developer supply port 52 to the developer reservoir 43A, and is conveyed from left to right in FIG. The developer moves to the developer reservoir 43B, where it is conveyed from right to left by the rotation of the screw 47, and further returns to the developer reservoir 43A on the left side of the partition plate 49. The developer is sufficiently agitated during the process of being circulated and conveyed through the developer reservoirs 43A and 43B, and is sufficiently charged by friction between the particles to become ready for development.

Reference numeral 42a in FIGS. 7 and 8 is a clutch used to engage a clutch of a motor (not shown) to rotate the magnet 42, which will be described later, and is fixed to the end of the magnet 42.

In the above apparatus, the developing units 31Y, 31M, 31C1
31K, as shown in an enlarged view in FIG. 11, a non-magnetic developing sleeve 41, which is a developer transport carrier, rotates counterclockwise, and a magnet body 42 is stationary and located inside the developing sleeve 41, and the developer is transported. The developer in the reservoir 438 is removed from the developing sleeve 41.
0 surface and is conveyed in the opposite direction to the rotation of the magnet body 42. The developer conveyed on the developing sleeve 41 is made of a magnetically permeable material and passes through the developing sleeve 41 on the way.
The thickness is regulated by a driven layer thickness regulating roller 44,
Form a developer layer. The layer thickness is controlled by the pressing force of the layer thickness regulating roller 44 against the developing sleeve 41.

Note that the magnet body 42 may be rotated in the opposite direction or the same direction as the developing sleeve 41.

When developing, a DC bias voltage and/or AC voltage is applied to the developing sleeve 41 by a bias power source (not shown). As a result, development is performed in the development area E, and the developer layer that has passed through the development area E is removed by the scraper 45.
The developer is scraped off from the developer sleeve 41 by the developer, and is returned to the developer reservoir 43A through the opening 48a of the canopy 48.

When using a two-component developer consisting of toner and carrier, the yellow, magenta, cyan, and black toners T adhere to the surface of the photosensitive layer 1b of the photoreceptor 1 one after another, and the toners T adhere to the surface of the photoreceptor layer 1b of the photoreceptor 1 in the next rotation of the photoreceptor 1. Moving on to the recording paper P (see FIG. 5), which is sometimes supplied to the surface of the photosensitive layer 1b, as described above, the recording paper P
is transferred and fixed to form a multicolor image.

By structuring the developing device as described above, the conveying path of the developer becomes long, and the stirring during this time allows for sufficient charging, and a good image can be obtained.

Further, since the developer O is conveyed by the developing sleeve 41 and the toner T is transferred to the photoreceptor 1 located directly above it, unnecessary developer is deposited on the photoreceptor as in the case of developing from above the photoreceptor. There is no risk of the developer falling to the surface, and more developer is consumed than necessary. Furthermore, the above effect makes it possible to use an endless belt-like photoreceptor, which makes it possible to flatten the image forming device, so that even when forming full-color images, the image forming device does not become huge, and the same It is convenient for manufacturing the image forming apparatus because the designed developing device can be used.

As described above, it is necessary that the photoreceptor and the developing sleeve face each other with a predetermined minute gap therebetween. In this example, the diameter of the developing sleeve 41 shown in FIG.
mm, and the distance d between the photoreceptor 1 and the developing sleeve 41 is 0.
It is set to 5mm.

What should be noted in this example is that the interval d is set as follows.

Figure 1 is a partially enlarged view of Figure 5, Figure 2 is from ■-■ of Figure 1.
FIG.

On the lower surface of the platen 9, an arcuate convex portion 9a is provided in a portion facing the developing sleeve 41 and a portion to which the image exposure light is irradiated, and shallow recesses 9b are provided in other areas.
If the photoreceptor 1 travels accurately at the position of the convex portion 9a and the photoreceptor 1
This is to reduce the friction between the platen 9 and the platen 9. The width of the photoreceptor 1 is larger than the length of the developing sleeve 41, and both side edges of the photoreceptor 1 protrude from the developing sleeve 41. Lining members 1 are provided on the inside of both sides of the photoreceptor 1.
A backing member 1C11C is fitted into a groove 9C19C provided in the platen 9 to prevent the photoreceptor 1 from swinging in a direction perpendicular to the running direction.

A developing sleeve position regulating member (hereinafter simply referred to as "position regulating member") is attached to the shaft 41a of the developing sleeve 410.

55 is externally fitted, and the developing sleeve 41 is rotatably supported by the position regulating member 55, and the position regulating member 55 is supported by the side walls 50a and 50b of the chassis 50 of the developing device. Springs 59 and 59 attached to the bottom wall 58 of the image forming device housing connect bars soh and soh fixed to the chassis side walls 50a and 50b.
is pushed up, thereby urging the chassis 50 upward, the upper end surface of the position regulating member 55 comes into contact with the lower side edges 9d of the platen 9, and the distance d between the photoreceptor 1 and the developing sleeve 41 is increased as described above. The developing sleeve 41 is positioned with respect to the platen 9 so that it has a predetermined size.

In FIG. 2, the position regulating member 55 has a rolling bearing structure, but it may also be a sliding bearing.

The photoreceptor is held in the photoreceptor holder in the following manner. A semicircular inner peripheral surface 6 provided on one end side of the photoreceptor holder 61A.
The shaft 2Aa of the pulley 2A is pivotally supported on the pulley shaft 61a having a diameter 1c, and the pulley shaft 61 has a quarter-circular inner circumferential surface 61d provided on the other end side of the photoreceptor holder 61.
A shaft 2Ba of a pulley 2B is supported by the shaft 1b. In this way, the photoreceptor 1 is held on the photoreceptor holder 61A via the pulley 2A12.

The platen is positioned as follows. Platen 9
A through hole 9e is provided in the through hole 9e, and a guide bar 65 fixed to the side wall (not shown) of the case of the image forming apparatus is inserted into the through hole 9e.
It is inserted with sufficient play. A positioning plate 62 is fixed to the platen 9, and the plate 62 is provided with a slot 62a into which a guide bar is fitted. A pin 63 is fixed to the plate 62, one end of the tension coil spring 64 is connected to the pin 63, and the other end is connected to the guide bar 65.
It is hung on. Plate 6 by coil spring 64
2 is urged to the right in the figure, and the semicircular inner circumferential surface 62b at the tip of the plate comes into contact with the shaft 2a of the pulley 2B, positioning the platen 9 to which the plate 62 is fixed, and the platen convex portion 9a. The leading end now accurately faces the developing sleeve 41.

Each developing device is held in a developing device holder in the following manner.

The developing device holder 71A has left and right side walls 71 in FIG.
a, 71b, and four developing device storage spaces 71d, 71d, 71d, 71d are formed between the side walls 71a, 71b by three partition walls 71c, 71c, 71c. Each developer housing space 71d has the same width dimension. The widths of the developing units 31Y, 31M, and 31C131 are substantially the same as the width of the developing unit accommodating space 71d, and the developing units 31Y, 31M, and 31C131K are arranged in each developing unit accommodating space 71d.
is accommodated from below. As shown in Figures 1 and 2, the cup,
A compression coil spring 59 attached to the bottom wall 58 of the image forming device housing and a spring receiver fixed to the side walls 50a and 50b of the developer chassis 50 bias the bar 60 upward, thereby causing the developer units 31Y and 31M to move upwardly. , 31C131K are urged upward. Since four developing devices are accommodated in the single developing device holder 71A in this manner, each developing device can be easily assembled into the image forming apparatus.

The developing sleeve of the developing device is positioned with respect to the platen as follows.

FIG. 3 is an enlarged perspective view of the chassis side wall 50b.

The chassis side wall 50b (50a) has a circular inner peripheral surface 50.
C, and a cut 50d is formed at the upper end.

The developing sleeve 41 is attached to the chassis side wall 5 as shown in FIG.
Set to 0b.

First, the position regulating member 55 shown by the three-dot chain line is fitted onto the shaft 41a of the developing sleeve 41, which is shown by the two-dot chain line. This point is indicated by the three-dot chain arrow.

The position regulating member 55 is provided with a circular through hole 55e for fitting the shaft 41a, and consists of a small outer diameter section 55a and a large outer diameter section 55C. Convex portions 55b and 55d are provided at the upper portions of the small outer diameter portion 55a and the large outer diameter portion 55c, respectively, and the outer diameter of the small outer diameter portion 55a is equal to that of the chassis side walls 50a and 50 in FIG.
b The inner diameter of the circular inner peripheral surface 50C is the same as that of the convex portion 55.
The width of b is the same as the width of the cut 50d in FIG.

Next, as shown by the two-dot chain arrow, the position regulating member 55 is fitted into the chassis side wall 50b from the left side in the figure. Thus, in the position regulating member 55, the small outer diameter portion 55a fits into the circular inner circumferential surface 50C of the chassis side wall 50b, the convex portion 55b fits into the cutout 50d of the chassis side wall, and the large outer diameter portion 55C
is in contact with the side surface of the chassis side wall 50b, and the developing sleeve 4
1 is rotatably attached to the chassis side wall 50b via a position regulating member 55.

The developing sleeve 41 is attached to the chassis side wall 50a in the same manner as shown in FIG. Reference numeral 57 in FIG. 2 indicates a shaft 4 for positioning the developing sleeve 41 in the central axis direction.
It is divided into two by a cylindrical spacer that fits around 1a. Caps 56A and 56 are attached to the chassis side walls 50a and 50b, respectively, and the position regulating member 55 is attached to the chassis side walls 50a and 50b, respectively.
Be careful not to pull it out from 0a and 50b.

As described above, the developing sleeve 41 is moved to the position regulating member 5.
5.55, and is rotatably supported by the chassis side walls 50a, 50b via springs 59.59, and the upper surface of the convex portions 55d, 55d of the position regulating member 55.55 is pressed against the lower surface side edges 9d of the platen 9 by the biasing force of the spring 59.59. The developing sleeve 41 is accurately and easily positioned at a distance d from the photoreceptor 1. As a result, the visible image after development is good with no variation in density.

Note that the tips of the five platen protrusions 9a are not located on the same plane. Distance i between the plane containing the center axis of pulley 2A and 2 and the tip of the convex portion facing the developing device 31K
t is the smallest and is the distance between the plane and the convex portion facing the developing device 31M! , is the largest, and the plane and the developing device 31Y
, the distance 12 from the convex portion facing 31C is! 1 and! The size is between 3 and 3. However, with the above structure, each developing sleeve 41 is accurately positioned with an interval of d+ from each convex portion 9a of the platen.

In the above example, each side wall of the chassis is integrated, but
This is made into the shape shown by the imaginary line in Figure 3, and the upper end surface of the right side in the figure is moved upward), and the upper and lower parts are divided by a horizontal plane (shown by the imaginary line) passing through the center point of the circular inner circumferential surface 50C. It can be done. In this case, the small outer diameter portion of the position regulating member is fitted into the lower portion 50e, and then the upper portion 50e is fitted.
0f and 50g are fixed to the lower portion 50e.

When the chassis side wall 50a has such a structure, the spacer 57 shown in FIG. 2 does not need to be divided into two parts.

On each of the above sides, the concave-convex fitting between the convex portion of the position regulating member and the cut end (50d in FIG. 3) of the chassis side wall may be reversed as described above. That is, instead of providing a cut in the chassis side wall, a convex portion protruding into the inner circumferential surface 50c may be provided, and this convex portion may be fitted into a recess provided in the small outer diameter portion of the position regulating member.

Disaster Prevention I In the first embodiment, only a plurality of developing devices are held in a single developing device holder, but in this example, both a photoconductor and a plurality of developing devices are held in a single photoconductor/developing device. It is held in a holder.

FIG. 12 is a partial sectional view of a multicolor image forming apparatus similar to that shown in FIG. 1, and FIG. 13 is a sectional view taken along the line xm-xm in FIG. 12.

Note that parts common to those in FIGS. 1 and 2 are denoted by the same reference numerals, and their functions are the same as described above, so a description thereof will be omitted.

Photoreceptor 1, platen 9, and developing devices 31Y, 31M, 31
C131 includes a photoconductor holding section 615 and a developing device holding section 6.
It is held in an integrated photoreceptor/developing unit holder 61 consisting of 10 parts.

Photoreceptor 1 is held by photoreceptor holding section 615 as follows. The shaft 2Aa of the pulley 2A is pivotally supported by a pulley shaft support 61a having a semicircular inner peripheral surface 61c provided on one end side of the photoconductor holding portion 615, and the photoconductor/developing unit holder 61
A shaft 2Ba of the pulley 2B is pivotally supported by a pulley shaft support 61b provided on the other end side of B and having a quarter-circular inner circumferential surface 61d.

In this way, the photoreceptor 1 is held in the photoreceptor holding portion 615 via the pulley 2A.

Each developing device is held in the developing device holding section 610 in the following manner. The developer holding section 61D has left and right side walls 61e and 61f in FIG. 12, and between the side walls 61e and 61f, three partition walls 61g, 61g and 61g form four developer storage spaces 61h and 61h. , 61h, and 61h are formed.

Each developer housing space 61h has the same width dimension.

The widths of the developing units 31Y, 31M, and 31C131 are substantially the same as the width of the developing unit housing space 61h, and the developing units 31Y, 31M, and 31C131 are arranged in each developing unit housing space 61h.
K is accommodated from below.

And side walls 61e, elf and partition walls 61g, 61
g, female screws 66Aa, 66Aa, 66Aa provided on the bottom wall 66A attached to the lower end surface of 61g.

Set screws 59A, 59A, 59A that screw into 66Aa,
Developing unit 31Y, 31M, 31C131K by 59A
are pushed upward, and this causes the developing units 31Y, 31M,
As described above, the position regulating member 55 allows the 31C131K to be accurately positioned with respect to the platen protrusions 9a, 9a, 9a, 9a.

FIG. 14 is a schematic perspective view of the photoreceptor/developing device holder 61. FIG. In this way, a single photoreceptor/developer holder 6
Since the photoreceptor and four developing devices are accommodated in 1B, each developing device can be easily assembled into the image forming apparatus. Furthermore, since the photoreceptor/developing unit holder is replaced by a cartridge in this way, replacement is easy.

Each developing device can also be fixed to the developing device holder as shown in FIGS. 15 and 16.

Figure 16 is a sectional view similar to Figure 13 (XVI in Figure 15).
-XVI line sectional view), Fig. 15 is xv-xv of Fig. 16
It is a line partial sectional view.

In the developing device holding portion 710 of the photoconductor/developing device holder 71, there is a female thread 50h on the developing device side wall 50b (same as 50a).
Put the side plate 668 on the side wall 50b, screw the bolt 59 through the through hole 66Ba to the female thread 50h, and tighten.
0h fixes the developing device 31C (the same applies to 31Y, 31M, and 31) at a predetermined position. In this example, the female thread 50
The vertical position of each developing unit is determined by the position of h.

Note that the photoconductor holding section has the same structure as the photoconductor holding section 61S shown in FIGS. 12 and 13.

As shown in Figures 12, 13, 15, and 16, each developer is fixed to the developer holder with screws, so unlike fixing with a spring force, the fixation is easy. It is stable.

Each developing device can be fixed to the developing device holding portion by using not only the set screws and bolts described above but also other suitable locking members.

The developing sleeve of the developing device is positioned with respect to the platen as follows.

Other than the above, this embodiment is the same as in the first embodiment.

In Example 1, the developer can be fixed to the developer holder by screws as in Example 2, and in Example 2, the developer can be fixed to the photoconductor/developer holder as in Example 1. It can be done by spring.

Each side described above is an example of reversal development using digital exposure, and a two-component developer is used as the developer, but it goes without saying that a one-component developer consisting only of toner can be used. Note that three or more screws may be provided, and these may not be parallel to each other, or may have a flexible endless structure. Further, for conveying the developer, an appropriate conveying means other than a screw capable of conveying the developer while stirring may be adopted.Furthermore, the present invention is capable of sequentially transferring each color toner image on a photoconductor to a transfer body. This method can also be applied to full-color image formation in which the composite toner image on the transfer body is transferred to recording paper all at once. In this case, the transfer body is installed in place of the transfer means (the transfer pole 4 described above) of the image forming apparatus.

Effects of the Invention In the present invention, since the endless belt-like photoreceptor and the plurality of developing devices are held by respective holding means, the basic arrangement of the photoreceptor and each developing device can be changed by combining both holding means. In addition to being easy to determine, each developing device is provided with a developing device position regulating means that comes into contact with a guide means for guiding an endless belt-like photoreceptor and positions the developing device with respect to this guide means, so that the above-mentioned positioning can be easily determined. is done easily and accurately.

In addition, since a plurality of developers are held by a single developer holding means, these developers can be easily assembled into an image forming apparatus together with a single developer holding means. As a result of the above,
Assembling the image forming device becomes easier and productivity is improved, and the positioning of each developing device with respect to the photoreceptor becomes accurate and precise, and the visible image obtained by development is of high quality. .

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention; FIG. 1 is a schematic front view (partially enlarged view of FIG. 5) showing the positional relationship between the photoreceptor and the developing device, and FIG. Figure 3 is a perspective view of the side wall of the chassis of the developing unit; Figure 4 is a perspective view showing how to attach the developing sleeve to the side wall of the chassis of the developing unit; Figure 5 is a multicolor image formation Figure 6 is a block diagram of the copying operation, Figure 7 is a plan view of the developing device, Figure 8 is the front view, Figure 9 is the right side view, and Figure 10 is the left side view. 11 is an enlarged sectional view taken along the line XI-XI in FIG. 7, and FIG.
Schematic front view similar to the figure, Fig. 13 is xm-x of Fig. 12
14 is a schematic perspective view of a photoreceptor/developing device holder, and FIG. 15 is a schematic partial sectional view showing the positional relationship between the photoreceptor and the developing device according to another example (xv in FIG. 16). -xv
16 is a sectional view taken along the line XVI-XVI of FIG. 15. In addition, in the symbols shown in the drawings, 1... Endless belt-shaped photoreceptor 1c.
......Backing members 2A, 2B...Pulleys 2Aa, 2Ba
・・・・・・・・・Pulley shaft 9・・・・・・・・・
Platen 9c...Guide groove 9d...Contact surface 11...Laser optical system 31Y, 31M, 31C, 31K... Developing device 41 Developing sleeve 41a Developing sleeve shaft 50.60
・・・・・・Developer chassis 50a, 50b・
..... Side wall 55 of the chassis .....
・Developing sleeve position regulating member 58...Bottom wall of image forming device housing 59.64...Coil spring 59A...Stopping screw 59 days... Bolt 60... Spring holder is bar 61A... Photoconductor holder 61B, 71B
...... Photoreceptor/developing device holder 61a, 61
b・・・・・・Axis support 610.71D・・・・・・
...Developer holding section 61S...Photoconductor holding section 62...Positioning plate 66
A...Bottom wall 714 of the developing device holding section...
...Developer holder 71a, 71b.1 old...Holder side wall 71c...Holder partition wall ld...
...Developer housing space d+... Distance D between photoreceptor and developing sleeve... Two-component developer ■... ...Toner LE... Image reading section RE... Image forming section P... Recording paper. Agent Patent Attorney Hiroshi Rensei 4th figure 41 11th figure 51 engineering, 51M, OL,) 7th figure 8 31Y, 31M, 31C, 31 / 3+Y, 31M, 31C, 蒐 figure 9

Claims (1)

[Claims] 1. An endless belt-shaped photoreceptor that can be rotated, a photoreceptor holding means that holds the photoreceptor, a plurality of developing devices, and a single developing device holder that holds the plurality of developing devices. and a guide means located on the opposite side of the photoreceptor from the developing device to guide the photoreceptor, and abuts against the guide means to position the developing device with respect to the guide means. An image forming apparatus in which a developing device position regulating means is provided in each of the aforementioned developing devices. 2. The image forming apparatus according to claim 1, wherein the single developing device holding means holds the photoreceptor together with the plurality of developing devices. 3. The image forming apparatus according to claim 1 or 2, wherein each developing device is fixed to a single developing device holding means by elastic means. 4. The image forming apparatus according to claim 1 or 2, wherein each developer is fixed to a single developer holding means by a fastening means.