JPH03144465A - Color image forming device - Google Patents

Abstract

PURPOSE:To facilitate maintenance work of a device regardless of the attachment or detachment of each unit by opening a recording paper feeding and carrying route from a paper feed cassette to a belt-like image forming body unit or to a fixing unit. CONSTITUTION:The recording paper feeding and carrying route from the paper feed cassette 14 to the belt-like image forming body 1 or the fixing part 18 is opened. In addition to the easier handling of troubles related to the paper feeding and carrying system such as removal in a jammed paper, the adoption of the belt-like image forming body makes the device compact, and copying and maintaining operations can be performed from only the front side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image forming apparatus in which a toner image is formed on a belt-like image forming member using an electrophotographic method and is transferred onto a transfer material to obtain an image. The present invention relates to an image forming apparatus.

[Background of the invention]

There are many ways to obtain color images using electrophotography.
A device has been proposed. For example, JP-A-61-10077
As disclosed in Publication No. 0, a latent image is formed and developed in accordance with the number of separated colors of the original image on a photoreceptor drum serving as an image carrier, and each time the development is performed, the latent image is transferred onto a transfer drum. There is a method of forming a multicolor image on a paper and then transferring it onto recording paper to obtain a color copy. In addition to the photoreceptor drum, the device using this method requires a transfer drum large enough to transfer one image on its circumferential surface, and the device does not have a large and complicated structure. Inevitable.

For example, as disclosed in Japanese Patent Laid-Open No. 61-149972, a latent image is formed and developed on a photoreceptor drum according to the number of separated colors of the original image, and is transferred onto a transfer material each time it is developed. This is a method of obtaining multicolor copies. With this method, it is difficult to overlap multicolor images with high precision, and it is impossible to obtain high-quality color copies.

Another method is to repeatedly form a latent image on a photoreceptor drum according to the number of separated colors of an original image and develop it with color toner, and then overlap the color toner images on the photoreceptor drum and then transfer the images to obtain a color image. The basic process of forming a multicolor image is disclosed in Japanese Patent Application Laid-open No. 60-75850 and No. 60-7 by the present applicant.
No. 6766, No. 60-95456, No. 60-9545
No. 8, No. 60-158475, etc.

In a multicolor image forming apparatus that obtains a color image through such superimposition, a plurality of developing units containing different color toners are arranged around the periphery of the photoreceptor drum. The photoreceptor drum is rotated multiple times to develop the latent image on the photoreceptor drum to obtain a color image.

Regarding the image forming body, as explained above, there is a photoconductor drum in which a photoconductor is coated or vapor-deposited on the circumferential surface of the drum, and a belt-shaped image forming body in which a photoconductor is coated or mounted on a flexible bell mill. has also been proposed. The shape of a belt-shaped image forming body (hereinafter also referred to as a photoconductor belt) is determined by stretching it between rotating rollers including a driving roller.
This is effective when configuring a compact color image forming apparatus that utilizes space effectively. In addition, since the photoreceptor belt can run along a small curvature, it is possible to prevent poor separation of the transfer material by using a rotating roller with a small diameter and using this curvature to separate the transfer material. can.

Also, JP-A-63-244059, JP-A No. 63-2440
In an image forming apparatus using a process cartridge disclosed in Publication No. 64, etc., a structure in which the conveyance path is divided when handling a jam has been proposed. The split structure has many difficulties in device manufacturing and user operation.

[Purpose of the invention]

In order to limit the height of the apparatus, such a photoreceptor belt is stretched horizontally flat, and image forming means such as developing devices are arranged in parallel on the underside of the photoreceptor belt. .

The aforementioned photoreceptor belt and developer group are each housed as a unit in the main body of the apparatus, and the paper feed cassette for storing the recording paper can also be stored in a stacked state using the space below them. In image forming apparatuses that use such photoreceptor belts, the paper feed and conveyance path for recording paper is often formed vertically from bottom to top on the side of the main body of the apparatus. The structure is such that it is not possible to open the paper feed conveyance path just by taking it out, which poses problems in the workability of jam removal and maintenance.

As a result of solving this problem and improving the present invention, even in an apparatus in which the recording paper feeding path is vertically formed, the paper feeding path can be freely opened and jams can be cleared regardless of whether each unit is attached or detached. The object of the present invention is to provide a color image forming apparatus in which maintenance work can be easily performed.

[Structure of the invention]

The above object is to provide at least a belt-like image forming member or a plurality of developing unit units below the belt-like image forming unit unit in a removable manner to an apparatus main body, and a paper feed cassette is disposed below the plurality of developing unit units. The present invention is closely related to a color image forming apparatus characterized in that a paper feed conveyance path for recording paper from the paper feed cassette to the belt-shaped image forming body unit or the fixing section can be opened.

〔Example〕

Embodiments of the color image forming apparatus of the present invention are shown in FIGS. 1 to 13.

In FIG. 1, l is a flexible photoreceptor belt which is a belt-like image forming member, and the photoreceptor belt l-1 is installed between rotating rollers 2 and 3, and is driven by the rotating roller 2. Transported clockwise.

Reference numeral 4 denotes a guide member fixed to the main body of the apparatus so as to be inscribed in the photoreceptor belt l, and when the photoreceptor belt l is brought into a tensioned state by the action of the tension roller 5, its inner circumferential surface is guided by the guide member 4. Let it rub. Note that the guide member 4 is provided with a recessed portion in an area unnecessary for image formation to reduce resistance due to rubbing. Of course, this recess does not need to be provided if the sliding resistance is low. In addition, in order to reduce the sliding resistance between the photoreceptor belt l or the guide member 4, a low-friction member such as Teflon coating is provided on the surface of either the photoreceptor belt l-1 or the guide member 4, or the low-friction member is It is preferable to consist of:

Therefore, the photoreceptors on the outer circumferential surface of the photoreceptor belt l are always maintained at a constant position relative to the surface of the guide member 4 even during conveyance, making it possible to form a stable image forming surface.

Further, by providing the developing device and the cleaning device below the photoreceptor belt, it is possible to prevent the developer from scattering or spilling.

6 is a scorotron charger which is a charging means; 7 is a laser writing system unit which is an image exposure means; and 8 to 11 are developing devices which are a plurality of developing means each containing a developer of a specific color. is arranged at a position facing the guide member 4 of the photoreceptor belt l. In order to maintain a gap without interfering with the movement of the photoreceptor belt 1, the guide member 4 is brought into contact with the guide member 4 on the outside of the photoreceptor belt 1 with a gap maintaining means.

In addition to the optical system shown in the drawings, the laser writing system unit 7 may also include an optical system that integrates a light emitting section and a convergent light transmission body.

Each of the developing devices 8, 9. , 10.11 respectively contain, for example, yellow magenta, cyan, and black developers, and are provided with respective developing sleeves 8A, 9A, IOA, and IIA that maintain a predetermined gap with the photoreceptor belt l. -1 has the function of visualizing the latent image on 1 by a non-contact development method. Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

12 is a transfer device, 12A is a static elimination plate, 13 is a cleaning device, and a blade 13A and a toner conveying roller 13B of the cleaning device 13 are connected to the photoreceptor belt 1 for image formation.
The photoreceptor belt 1 is kept in a position apart from the surface of the photoreceptor belt 1, and is pressed against the surface of the photoreceptor belt 1 as shown in the figure only during cleaning after image transfer.

The process of forming a color image by the color image forming apparatus is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the image forming system shown in FIG. In other words, the color image data input section (Figure 2 (a)) where the image sensor scans the original image.
) is processed by the image data processing section (FIG. 2 (b)) to create image data, which is then stored in the image memory (FIG. 2 (c)). Then, the image memory is taken out at the time of recording and sent to the recording section (FIG. 2 (d)).
For example, the image data is input to the color image forming apparatus shown in the embodiment of FIG.

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit 7, the laser writing system unit 7 outputs a laser beam generated by a semiconductor laser (not shown). is rotated and scanned by a polygon mirror 7B rotated by a drive motor 7A, and passes through an fθ lens 7C to mirrors 7D and 7E.
The optical path is bent by this, and the light is projected onto the circumferential surface of the photoreceptor belt 1, which has been charged in advance by a charger 6, which is a charging means, to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the photoreceptor belt 1. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is reversely developed in a non-contact state by a developing device 8 loaded with a yellow O-(Y) toner (head image medium) of the developing means, and a toner image is formed on the belt surface. The obtained toner image, while being held on the belt surface, passes under a cleaning device 3, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor bell I-1 is charged again by the charger 6, and then the second color signal output from the signal processing section is input to the writing system unit 7, and the above-mentioned first color signal is Writing is performed on the drum surface in the same manner as in the case of the drum surface, and a latent image is formed. The latent image is reversely developed in a non-contact manner by a developing device 9 loaded with magenta (M) toner as a second color.

This magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

A developing device 10 has cyan (C) toner, and forms a cyan (C) toner image on the drum surface based on a control signal generated by a signal processing section.

Further, numeral 11 denotes a developing device having black toner, which forms a black toner image superimposed on the drum surface by the same process. These developing units 8°9.108 and 11
A direct current or even an alternating current bias is applied to each sleeve, and jumping development is performed using a T-component or two-component developer, which is a developing means, and non-contact development is performed on the photoreceptor belt L whose base is grounded. It is about to be done.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is transferred to a transfer material fed from the paper feed cassette 14 via the paper feed guide 15 at the transfer section.

That is, the top layer of the transfer material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the transfer device 12 via the timing roller 17 in synchronization with the image formation on the photoreceptor belt l. supplied to.

The transfer material that has undergone image transfer and charge removal is reliably separated from the photoreceptor belt l, which suddenly changes direction along the rotating roller 2, without being affected by image quality such as toner scattering due to the charge removal effect. After the image is fused by the fixing roller 18, the sheet is discharged onto the tray 20 via the discharge roller 19.

On the other hand, the photoreceptor belt 1 that has completed the transfer to the transfer material continues to be transported, and the cleaning device 13, in which the blade 13A facing the rotation roller 3 and the rotating toner transport roller 13B are brought into pressure contact, removes the remaining toner. After the removal is completed, the blade 13A is separated again, and a little later, the toner conveying roller 13B is separated and a new image forming process begins.

The image forming means of the photoreceptor belt 1, guide member 4, scorotron charger 6, and cleaning device 13 are comprised of a process cartridge 30 comprising front and rear substrates 30A and 30B as shown in FIG. It is assembled into a belt-shaped image forming unit and is attached to and detached from the main body of the apparatus as a belt-shaped image forming unit.

The cartridge 30 integrates the front and rear substrates 30A and 30B via the guide member 4 and two stays 31, and holds the image forming means therebetween, and is attached to and removed from the main body of the apparatus.

On the other hand, each of the above-mentioned developing units is incorporated into an integral and flexible developing container 41 as shown in FIG. It is attached and detached.

The developing container 41 has a plurality of compression springs 43 disposed in the front and back direction sandwiched between the bottom surface corresponding to the developing devices 8 and 11 and the supporting base 42, so that the circumferential surfaces of the developing sleeves are in contact with each other. The curvature of the curved surface formed by the guide member 4
The photoreceptor belt 1 is stored in the main body of the apparatus in a state in which it is locked by the claw portion 42A so that the curvature is smaller than the curvature of the image forming surface of the photoreceptor belt l formed by.

The cartridge 30 and the developing unit 40 have an upper cover 50 of the apparatus main body shown in FIG.
It is inserted into the apparatus main body from above by standing up at a substantially right angle to the back side using A as a fulcrum and opening it.

That is, the cartridge 30 and the developing unit 40 are respectively attached with rotatable handles 32 and 44 that can be set in a suspended state as shown by the dashed line, and when the upper cover 50 is opened, First, the developing device unit 40 is placed into the tray 45 inside the main body of the apparatus using the handle 44 .

Next, the cartridge 30 is inserted diagonally from the upper right side of the apparatus main body through the handle 32, and the shaft ends 2A and 3A of each rotary roller protruding from the front and rear sides are engaged with the guide grooves 51A and 51B formed in the apparatus side plate 51, It is located above the developing unit 40 against the push-up spring 52.

The handles 32 and 44 have twisting bars 32A and 44A.
The photoreceptor belts l of the cartridges 30 are automatically stored in their respective storage positions, so the photoreceptor belts l of the cartridges 30 are set in the corresponding positions of each developing unit, and furthermore, by closing the upper cover 51, the pair of pressing members 50B on the front and rear of the cartridges 30 are pressed into contact with each other. Accordingly, the developing interval between each developing sleeve is set.

Further, in the color image forming apparatus of the present invention, the paper feed cassette 14 can be inserted into the back of the front of the main body of the apparatus and stored at the bottom thereof, and the left side where the recording paper feed conveyance path is provided can be opened. As a result, each operation of the apparatus and maintenance work including jam removal etc. can be performed only from one side of the front of the apparatus.

FIG. 5 shows an example in which the horizontal cover 60 covering the left side of the apparatus main body is opened clockwise as shown by a dashed line with the fulcrum being coaxial with the paper ejection roller 19 at the upper part of the apparatus main body. One member of six pairs of paper feed guide 15, timing roller 17, and fixing roller 18 and the transfer device 12 are attached and supported by the cover 60, and when the horizontal cover 60 is opened, the paper is ejected from the paper feed roller 16. roller 19
The paper feed and conveyance path for the recording paper is completely opened.

When the horizontal cover 60 is opened using the upper part of the apparatus main body as a fulcrum, the fixing roller 18 is close to the fulcrum position, so a strong pressing force can be obtained by closing the lid, ensuring reliable fixing and conveying effects. will be held.

Further, as shown in FIG. 6, the support shaft 70A of the horizontal cover 70
It is also possible to provide the horizontal cover 70 at the bottom of the main body of the apparatus and open the horizontal cover 70 in the counterclockwise direction. In this case, the paper feed conveyance path is wide open at the top, so there is an advantage that work such as jam removal can be performed extremely easily.

If the fixing roller 18 is structured so that it can be rotated by external operation, there is no need to open the pressure bonding surface when clearing a jam, so the horizontal cover 80 can be downsized as shown in FIG. In addition to simplifying the structure, it is also possible to make jam removal and maintenance work easier.

Further, as shown in FIG. 8, the present invention provides a front cover 100 on the front surface of the main body of the apparatus in place of the upper cover 50, and opens the front cover 100 at a substantially right angle to the front with the support shaft 100A as a fulcrum. The present invention can also be applied to a color image forming apparatus in which the cartridge 130 and the developing unit 140 are installed and removed from the apparatus horizontally.

9 and 11 show the process cartridge 130.
10 and 12 show the developing unit 140 and its BB cross section.

The cartridge 130 has front and rear boards 13OA and 1
A pair of engagement pins P1 and P2 are provided at mutually opposing positions on each outer surface of the cartridge 130B, and on the other hand, the engagement pins P1 and P2 are pressed on the device main body side to accommodate the cartridge 130 in the device main body. A biasing device is provided for biasing into position.

In FIG. 1I, 101 is a stop plate that regulates the lower limit position of the engagement pin P1 of the cartridge 130 attached to the inner surface of the front cover 100, and 102 is an inclined surface 102A, which is guided to slide downward by the action of a tension spring 103. When the pressure bonding plate 102 is inserted and the cartridge 130 is not inserted, the pressure bonding plate 102 is maintained at a position slightly lower than the illustrated position.

On the other hand, ill is a long rear side plate 110B provided to fit the engagement pin P2, and 112 is a crimp plate having an inclined surface 112A and guided to slide downward by the action of a tension spring 113, into which the cartridge 130 is inserted. If not, the pressure bonding plate 112 is kept at a position slightly lower than the illustrated position.

On the other hand, the developing device unit 140 is
An engaging hole H is provided in a bent portion 142B at the center of the front surface of the device 2, and a pair of bent portions 142C on the rear surface, respectively.On the other hand, on the device main body side, engagement holes H are provided in the inner surfaces of the front cover 100 and the rear side plate 110B of the main body, respectively. An engagement pin P3 that fits into the engagement hole H and a pair of retaining pins P4 are attached.

To install the cartridge 130, first insert the engagement pin P2 on the rear surface into the elongated hole Ill of the rear side plate 110B. When the engagement pin P2 is inserted into the elongated hole 11, it pushes the inclined surface 112A and slides the crimp plate 112 upward, but after the engagement, it is pressed against the lower end of the elongated hole 111 by the pressing force of the crimp plate 112, As a result, the cartridge 130 receives a moment in the clockwise direction about the engagement with the elongated hole Ill as a fulcrum, and maintains its front surface at a position slightly higher than the horizontal state.

Hence said cartridge! 30 is in an inclined position with the front side facing upward, and can be attached to and removed from the main body of the apparatus without interfering with the developing unit 140 installed below.

The cartridge 130 is automatically set in a predetermined storage position by closing the front cover 100, whereby the image forming surface of the photoreceptor belt 1 is set at a position forming a predetermined development interval with each of the developing sleeves. be done.

That is, in the process of closing the front cover 100, the crimp plate 102 presses down the engagement pin PI which is located at a position slightly higher than the horizontal state by the inclined surface 102A, and when the lid is closed, the crimp plate 102 crimp the engagement pin PI as shown in the figure. It is held and supported between the plate 102 and the stop plate 101.

On the other hand, when installing the developer unit 140, first insert the engagement hole H of the bent portion 142B on the rear surface into the rear side plate 1.
10B, and the bent portion 142B
is supported by the bent portion of the front side plate 110A, and then, by closing the front cover 100, the engaging pin P3 is fitted into the engaging hole H of the bent portion 142B, and the developing unit 140 is closed. It is set in a predetermined storage position within the main body of the device.

As a result, the developing device unit 140 is kept horizontal and is pressed against the cartridge 130, so that the abutting rollers of each developing device, which will be described later, are pressed against the guide member 4, and each developing sleeve and photoreceptor belt are pressed against each other. 1 is set. When the developer unit 140 is pressed against the developer unit 140, the flexibility of the developer container 41 itself and the elasticity of the compression spring 43 acting on the developer container 41 cause the abutment rollers of each developer sleeve to move against the curved surface of the guide member 4. It can be properly pressed under various loads.

Regarding the main body of the apparatus in which the process cartridge 130 and the developer unit 140 are inserted and removed from the front, a horizontal cover 200 that opens and closes using the support shaft 200A as a fulcrum is provided as shown in FIG. 13, and paper is fed to the horizontal cover 200. By mounting and supporting each member forming the conveyance path, the recording paper conveyance path can be opened by opening the horizontal cover 200.

Note that the opening direction of the horizontal cover 200 and the range of the conveyance path to be opened can be freely selected and used, as in the case of the example of the apparatus equipped with the upper cover 50 described above.

〔Effect of the invention〕

The present invention not only makes it extremely easy to troubleshoot troubles that occur in the paper feed and conveyance system, such as removing and removing jammed recording paper, but also makes the device more compact by adopting a belt-like image forming body. It is possible to handle all copying operations and maintenance work with just one machine.In particular, the heater roller of the fixing section is separated from the main body of the machine and divided into 6 transport paths including the pressure roller, and maintenance operations such as jam removal etc. In addition, wiring processing and other transportation steps have been greatly simplified, and an extremely useful color image forming apparatus has been provided that can provide a stable pressure force during heat roller pressure fixing and improve image quality. It happened.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing the basic functions of a color image forming apparatus of the present invention, FIG. 2 is a block diagram showing an image forming system, and FIGS. 3, 9, and 4. FIG. 10 is a configuration diagram of each process cartridge and each developing device unit, FIGS. 11 and 12 are sectional views of the main parts thereof, and FIGS. 5 to 7 and 13 are each showing an embodiment of the present invention. An explanatory diagram of the configuration of the device, and FIG. 8 is an external perspective view of the device. l...Photoreceptor belt 4...Guide member 6...
・Charger 7...Laser writing system unit 8.9, lO, li...Developer 12...Transfer device 1
3...Cleaning device 14...Paper cassette 1
5...Paper feed guide 16...Paper feed roller 17
... Timing roller 18 ... Fixing roller 19.
... Paper ejection roller 20 ... Tray 30.130
...Process cartridges 40, 140...Developer unit 50...Top cover 60.70.80,20
0... Side cover 100... Front cover

Claims (1)

[Claims] A color image forming apparatus comprising at least a belt-shaped image forming member or a plurality of developing unit units removably provided below the belt-shaped image forming unit unit, and a paper feed cassette disposed below the plurality of developing unit units. In,
A color image forming apparatus characterized in that a paper feed conveyance path for recording paper from the paper feed cassette to the belt-shaped image forming unit or the fixing section can be opened.