JP2759286B2 - Color image forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a color process cartridge in which a plurality of developing means containing a multi-color developer and an image carrier can be detachably provided in an apparatus main body. The present invention relates to a small and lightweight electrophotographic color image forming apparatus, and more particularly to a compact color printer.

[Background of the Invention]

Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, as disclosed in JP-A-61-100770, a latent image is formed and developed on a photosensitive drum in accordance with the number of separated colors of an original image, and transferred to a transfer drum each time development is performed. There is a method in which a multicolor image is formed on a transfer drum and then transferred onto a recording paper to obtain a color copy. In the apparatus according to this method, it is necessary to provide a transfer drum having a size capable of transferring one image on the peripheral surface in addition to the photosensitive drum, and the apparatus has a large and complicated structure. Inevitable.

In addition, a latent image is formed on an image carrier by a dot exposure scanning writing system such as a semiconductor laser and an LED, and further, a CCD,
Japanese Patent Application Laid-Open No. 61-73977 discloses a method for performing a so-called digital color image processing having a color image information reading system using a solid-state imaging device such as a-Si. Such a problem is occurring.

Further, there is a method in which a latent image is formed on the photosensitive drum in accordance with the number of separated colors of the original image and development with a color toner is repeated, and a color image is obtained by superimposing and transferring color powder on the photosensitive drum. The basic process of this multicolor image formation is described in Japanese Patent Application Laid-Open Nos. 60-75850, 60-76766 and 60-95 by the present applicant.
Nos. 456, 60-95458 and 60-158475.

In a multi-color image forming apparatus that obtains a color image by such superposition, a plurality of developing devices that store color toners of different colors are arranged on the periphery of the photosensitive drum. Rotates the photoconductor drum several times,
The color image is obtained by developing the latent image on the photosensitive drum.

On the other hand, regarding the structural aspects,
As disclosed in Japanese Patent Application Laid-Open No. 58-54392, a proposal has been made in which a photoconductor drum, a developing device, and a cleaner are integrally mounted on a support member to facilitate replacement and repair of each unit.

In addition, as a compact monocolor-compatible device which is small and can be easily handled by ordinary users, a device in which these integrated components are further configured in a disposable format is disclosed in Japanese Patent Application Laid-Open No. 57-15 / 1982.
No. 4255 discloses this.

Further, as a printer that incorporates a laser writing system into a substantially similar apparatus, Japanese Patent Laid-Open No. 147366/1984 is disclosed.

Further, as an apparatus for forming a mono-color or full-color image, a disposable single-color process cartridge and a disposable (color) cartridge containing a plurality of developing units are also interchangeable. Japanese Patent Application Laid-Open No. 58-72159 proposes a multi-color image forming apparatus, which is not an easy-to-operate, small-sized, and inexpensive apparatus. Has not been reached.

Further, the applicant has disclosed in Japanese Patent Application Laid-Open No. 63-293563 various types of exchanges such as a single-color cartridge or a color cartridge having a plurality of developing devices as a similar one, and is also capable of being inserted into and removed from the apparatus main body. Japanese Patent Application Nos. 62-234493 and 62-234493 disclose a color image forming apparatus in which a pedestal is provided and a photosensitive drum, a plurality of developing units or a cleaner and the like are detachably mounted on the pedestal.
No. 239748, etc., but lack of user-friendliness due to imbalance in the life of consumables such as toner or developer contained in multiple developing units, the internal mechanism is complicated, and the device is large. However, there has been a great problem that a compact and inexpensive device has not been provided and user loss has occurred.

In particular, the above-mentioned gazette which discloses a disposable cartridge employs a configuration in which a disposable process cartridge is replaceable in an upper housing having a two-part structure, and is intended to solve the operability of cartridge replacement and the ease of jam clearance. . With particular emphasis on the ease of replacement of the process cartridges, particularly the replenishment toner cartridge and the recovery toner cleaning cartridge, the process cartridge is divided into two parts, and especially the process cartridge is placed in the lower housing to improve the workability of maintenance. The above-mentioned method is disclosed in JP-A-58-1161.

[Problems to be solved by the invention]

However, in a color process cartridge in which the plurality of developing units and the image carrier are replaceable with respect to the apparatus main body, loading and unloading to and from the apparatus main body is easy, and toner or developer from the plurality of developing units is used. No compact color printer having a color process cartridge free from such problems, such as leakage of prints, bleeding, etc., and no problem even in the case of jam processing of a transfer material, has been proposed.

In particular, a disposable cartridge is provided in an upper housing of a two-part structure which facilitates the jam processing.
A process cartridge is provided in the lower housing in order to facilitate replacement of replenishment and collected toner as disclosed in JP-A-72159, etc., and a process cartridge such as development, cleaning, and a photosensitive drum is lifted upward during jam processing. In the structure disclosed in Japanese Patent Application Laid-Open No. Sho 58-1161, the workability of replacement and the ease of jam clearance are contradictory.
Due to the transport system, even if the cartridge is tightly sealed to prevent toner spills due to process cartridge replacement, external vibrations and shocks to the machine body, toner spills from the developing unit and cleaner may occur. This has caused the transfer paper to be stained.

On the other hand, a printer as shown in FIG. 7 is disclosed in Japanese Utility Model Application Laid-Open No. 63-195357 as a configuration capable of avoiding such structural defects. The printer also has a built-in process cartridge inside, and a flat feed conveyance path is formed at the top, but at the same time that the transferred toner image surface faces downward, it is fixed from the transfer material separation portion of the photosensitive drum 101 at the same time. The transport path leading to the section 102 is limited, and the problem of the transport section has not been solved. Further, the easiness of jam clearance in the case of the two-part division, and the overall compactness for the stack paper feed configuration of the upstand In particular, the device does not always provide excellent operability for the user, for example, when the shaft 103 is divided into two parts around the fulcrum, the opening angle of the upper housing is restricted.

Japanese Unexamined Patent Publications Nos. 64-40850 and 63-244059 disclose similar problems of transportability and jam clearance, but all of them have compactness including a paper cassette and a space. And lacked ease of use.

In particular, in color copying, the circumference of the photosensitive drum tends to be inevitably larger, and various arrangements such as reducing the space around the drum by rotating or moving these positions when arranging a plurality of developing units necessary for color image formation,
Although it is implemented, the diameter of the drum can not be reduced so much that the separation performance is reduced due to the increase in the diameter of the drum and the necessity of a separation mechanism and process and the securing of space are required. A major problem is the lack of a transport process in the case where a transport section, particularly a transfer sheet, from the feed section 4A or 4B is transported by gravity due to gravity.

Further, in forming a color image by the above-described superimposition process, a drum circumference corresponding to at least a maximum image width (a short diameter is possible) is required, and thus the above-mentioned problem relating to an increase in the diameter of the drum is particularly important.

Therefore, if an attempt is made to add a screen copy function to such an image forming apparatus, the mechanism becomes complicated, and at the same time, the volume of the apparatus, particularly the height in the vertical direction, increases, resulting in a significant decrease in operability.

The present invention has been made to solve the above various problems.

[Configuration of the invention]

The object is to have a charging device, a developing device group including a color toner developing device and a black toner developing device, a cleaning device, and a transfer / transfer means of a transfer paper on an image carrier drum and a peripheral edge thereof. In the color image forming apparatus described above, the upper housing has a transfer belt as a transfer / transporting means, and the upper surface of the upper housing is provided with a mounting portion of a sheet cassette positioned substantially horizontally in an open state. This is achieved by a color image forming apparatus provided with a paper feeding means for separating transfer paper one by one from a paper feeding cassette and feeding the same to the transfer conveyance means, and an intermediate stacker for reversing the transfer material. You.

〔Example〕

 One embodiment of the present invention is shown in FIGS.

 FIG. 1 shows an embodiment in which the present invention is applied to a printer.

The printer has a clamshell structure divided into an upper casing 1 including a transfer belt and an apparatus main body 2 corresponding to a lower casing including a color process cartridge. Can be opened and held at a predetermined angle by a hinge connected to the main body, and is integrated with the apparatus main body 2 by a stopper metal in a closed state.

The photosensitive drum 30 serving as an image forming member constituting the image forming portion of the printer, developing devices 36, 37, 38, and 39 containing yellow, magenta, cyan, and black developers, and a pressure release mechanism for the image forming member Cleaning device 40 having a charger
Each of the 35 devices is housed in an integrated color process cartridge 3 to form a unit.

The unitized process cartridge 3 is vertically inserted into the apparatus main body 2 from above by opening the upper housing 1 as shown in FIG. The upper housing 1 is fixed to the storage position by the action of a pressing member (not shown) interlocking with the closing of the lid of the upper housing 1.

In the process cartridge 3, each of the developing devices
36, 37, 38 and 39 are distributed to the left and right with respect to the center line of the photosensitive drum 30, that is, the developing units 36 and 37 are on the right side with respect to the axis of the photosensitive drum 30, and the developing units 38 and 39 are Are arranged at symmetrical positions on the left side, and the developing sleeves of the developing units 36 and 37 further arranged on the right side are clockwise, and the developing sleeves of the developing units 38 and 39 arranged on the left side are further By rotating in the counterclockwise direction, the developing operation of each image is performed.

By arranging such a group of developing devices and further reversing the rotation of the developing sleeve, the process cartridge 3 balances right and left both in terms of weight and power transmission mechanism, and has good handleability. Further, generation of harmful vibrations and the like can be prevented beforehand.

In addition, each developing device placed at the symmetrical position on the left and right can have a common structure, and the scraping of toner from the developing sleeve after the developing operation is completed can be extremely efficiently performed by the action of gravity. There is an advantage that a proper amount of fresh toner can be always supplied.

On the other hand, the cleaning device is
A toner collection box 47 is provided at 40 symmetrical positions so that the left and right weight balance of the process cartridge 3 is better. A toner conveying screw 48 is provided between the toner collection box 47 and the cleaning device 40.
Is mounted on the front surface of the process cartridge 3, and the waste toner separated from the peripheral surface of the photosensitive drum 30 by the blade 40A is transported by the thrust of the toner transport screw 48 to collect the toner. Collected inside box 47.

In addition, since each developing device is maintained in a posture in which the opening portion thereof is directed upward, the developer does not flow out and fall or mix in other developing devices.

In the printer, the laser writing unit B is disposed in a space beside the process cartridge 3, and the recording paper transport surface is disposed in a portion of the upper portion of the process cartridge 3 that extends over both the upper housing 1 and the apparatus main body 2. The photosensitive drum 30 receives a laser scan from the laser writing system unit B from obliquely below, and transfers a color toner image formed by being superimposed on the peripheral surface thereof to the lower surface of the recording paper. ing.

The color image copying process performed by the printer is performed as follows.

First, the formation of a multicolor image according to the present embodiment is performed according to the image forming system shown in FIG. That is, data obtained by a color image data input unit (FIG. 3A) in which an image sensor scans an original image is subjected to arithmetic processing by an image data processing unit equipped with a computer (FIG. 3B). Image data is created and temporarily stored in an image memory (FIG. 3 (c)). Next, the image memory is taken out at the time of recording and is inputted to a recording section (FIG. 3D), for example, 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 unit B, a laser beam generated by a semiconductor laser (not shown) is generated in the laser writing unit B. Is rotated by a polygon mirror 32 rotated by a drive motor 31, passes through an fθ lens 33, the optical path of which is bent by a mirror 34, and is provided with a charge by a charger 35 serving as a charging unit in advance. Projected onto it to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam is applied to the photosensitive drum 30.
Is scanned on the peripheral surface of. Accordingly, a latent image corresponding to the first color is formed on the peripheral surface of the photosensitive drum 30 by the main scanning by the laser beam and the sub-scanning by the rotation of the photosensitive drum 30. This latent image is developed by a developing device 36 loaded with yellow (Y) toner (a visual medium) in the developing means.
A toner image is formed on the drum surface. The obtained toner image passes under the cleaning device 40 as cleaning means separated from the peripheral surface of the photosensitive drum 30 while being held on the drum surface, and enters the next copy cycle.

That is, the photosensitive drum 30 is charged again by the charger 35, and then the second color signal output from the signal processing unit is input to the writing unit B, and the case of the first color signal described above is used. Similarly, writing is performed on the drum surface to form a latent image. The latent image is developed by a developing device 37 loaded with magenta (M) toner as the second color.

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

Reference numeral 38 denotes a developing device having cyan (C) toner, which forms a cyan (C) toner image on the drum surface based on a control signal generated by a signal processing unit.

Further, reference numeral 39 denotes a developing device having a black toner, which forms a black toner image on the drum surface by the same processing. A DC or further AC bias is applied to each of the sleeves of these developing units 36, 37, 38, and 39, jumping development is performed by a two-component developer as a visualizing means, and the photosensitive member whose base is grounded Development is performed on the drum 30 in a non-contact manner.

The color image thus formed on the peripheral surface of the photosensitive drum 30 is recharged by the charger 9 and fed from the paper feed cassette C, which is horizontally mounted on the upper surface of the upper housing 1 in the transfer section at the transfer section. The image is transferred to the lower surface of the recording paper sent through the guide.

That is, the multicolor toner image is charged by the pre-transfer charger 9 to facilitate the transfer, and then the transfer conveyance means, that is, the transfer belt 50 rotated from the start of the transfer is brought into contact with the photosensitive drum 30, and the paper cassette The image is transferred from C to recording paper supplied in synchronization with image formation via a paper supply roller 12 and a timing roller 13 which are also paper supply means provided in the upper housing 1.

The structure of the transfer belt 50 is such that a 0.5 mm thick elastic layer is provided on the outer periphery of a comb belt containing a conductive cloth as a base, and a 50 μm insulator layer (dielectric layer) is further provided on the outer periphery. The transfer belt 50 is in contact with or separated from the photosensitive drum 30 by being stretched between the rollers 60a, 60b, and 60c and rotated by the drive of the roller 60a, and the roller 60b moves up and down. The transfer belt 50 is charged by the transfer device 51, and the transfer belt 50 is charged.
Transfer is performed by applying a transfer charge of the opposite polarity of the toner of about 1.5 KV to 3.0 KV to the surface.

On the other hand, a photosensitive drum that separates the recording paper from the drum peripheral surface
At 30, the blade 40 </ b> A of the cleaning device 40 comes into contact to remove the remaining toner, and after the completion, the blade is separated from the drum peripheral surface again to enter a new color image format process.

In this way, the recording paper is
Is transported in the horizontal direction and the transfer surface is downward, so that even if toner spills or scatters from the cleaning device 40 or the like, the image surface is not contaminated. The transferred recording paper is discharged to the outside via a fixing roller 80 and a discharge roller 90.

Further, the color image forming apparatus of the present invention has a built-in reversing mechanism of the recording paper on which the image has been transferred to one side, so that the image can be continuously transferred to the other side to perform so-called double-sided copying. I have.

In FIG. 1, reference numeral 200 denotes an intermediate stacker for temporarily placing a transfer material on which an image has been transferred on one side, that is, a recording sheet, and is provided at an intermediate portion between the transfer belt 50 and a mounting portion of the sheet cassette C. ing.

One end of the intermediate stacker 200 is
The other end is connected to a paper feed unit A from the paper feed cassette C to the timing roller 13 via a transport guide 200B via a transport guide 200B.

T1 and T2 are switching members attached to the connection point between the conveyance guide 200A and the paper discharge port of the paper discharge roller 90 and the connection point between the conveyance guide 200B and the paper supply unit A, respectively. It can swing to the position indicated by.

Reference numeral 210 denotes a manual paper feed table, which is mounted above the paper feed roller 12 so that recording paper can be manually fed to the paper feed unit A via a conveyance guide 210A.

A switching member T3 that can swing like the switching members T1 and T2 is also provided at a connection point between the transport guide 210A and the paper feed path from the paper feed roller 12.

In performing so-called single-sided copying in which an image is transferred only to one side of the recording paper, the switching members T1, T2 and T3 are used.
Are placed in the state shown by the solid line, so that the recording paper discharged from the paper feed cassette C is linearly discharged from the paper feed section A and reaches the timing roller 13, and after the transfer is completed, the paper is discharged by the paper discharge roller 90. It is ejected to the outside and the copying is completed.

During double-sided copying, the switching members T1 and T3 are rotated to the state shown by the dashed line after the recording paper passes through the paper feeding section A by selection of the copy mode, and the transport roller 201 starts rotating.

Therefore, the recording paper after the first side has been copied is switched by the switching member.
It is guided by T1 and enters the conveyance guide 200A, where the conveyance roller 201
Is sent to the intermediate stacker 200 with the image surface facing upward and temporarily stopped.

Conveying roller in response to the start of the following second surface copy operation
Since the rotation of the conveyance roller 203 and the conveyance roller 203 starts, the recording paper starts to be conveyed again, is guided by the switching member T2, and is conveyed upward in the paper feeding section A.

Here, the recording paper is guided by the switching member T3 by the action of the transport roller 11 which is temporarily in the reverse rotation state, and the leading end of the recording paper is turned over on the manual paper feed table 210 with the image surface facing downward. When the rear end of the transfer paper passes through the switching unit T2 and is within the paper feeding unit A and before passing through the feed roller pair 11, the switching member T2 is moved to the position indicated by the solid line by the detection of the rear end passage by the sensor 300. And the transfer roller 12 is returned to the normal rotation, and the transfer sheet is conveyed in the path without being caught by the switching member T2 in the paper feeding section A with the rear end of the transfer sheet facing forward, and is sent to the transfer section. The image is transferred to the second surface with the image surface facing downward. Therefore, as the image formation on the back surface, an image signal which is laser-written with the rear end portion as the front end is transferred.

Thus, when the double-sided copy is completed, the double-sided copy mode is automatically reset, the rotation of each of the transport rollers 201, 202 and 203 is stopped, and at the same time, each of the switching members T1 and T3 is returned to the state shown by the solid line, and the single-sided copy is performed again. Return to the mode and discharge the recording paper that has completed the duplex copying to the outside.

Further, the color image forming apparatus of the present invention is capable of creating a so-called composite image in which two or more images are separately transferred onto the same surface of a recording sheet.

Switching members T1 and T2 depending on the selection of the composite copy mode
Since both are placed in the state indicated by the broken line, the recording paper on which the image has been transferred to one side is once placed on the intermediate stacker 50 with the copy side facing down as in the case of double-sided copy, carried out, carried out, and transport rollers 202 and Switching member T2 by rotating 203
And is conveyed to the timing roller 13.

Therefore, a composite image can be obtained by re-transferring the subsequently formed composite image onto the same surface of the already transferred recording paper.

When the number of images to be combined is set in advance and copying of a predetermined number of images is completed, the combined copy mode is reset, the rotation of each of the transport rollers 201, 202, and 203 is stopped, and at the same time, each of the switching members T1 and T2 is in a state indicated by a solid line. It is restored and returns to the normal single-sided copy mode.

As described above, in the color image forming apparatus of the present invention, various copy formats (modes) such as a normal one-sided copy, a two-sided copy, a composite copy, or a combination thereof are arbitrarily selected (operation not shown). It is desirable to be able to automatically sort (stack) the recording paper that has been discharged outside and stacked for each copy format. It is possible to select an insert (mode) in which sorting paper with more colors and the like is fed and inserted into the recording paper discharged via the transfer belt 50. In this case, all image processing functions are stopped. Only the transfer function operates.

In addition, it is also possible to convey the sorting paper directly onto the external laminated recording paper via the intermediate stacker 200 without passing through the transfer belt 50. In this case, the respective conveying rollers
Each of 201, 202 and 203 has a reverse rotation function, and the switching member T1 has a structure capable of retreating from the transport path.

The intermediate stacker 200 is configured to be further rotatable with respect to the lid upper housing 1 when the upper housing 1 is opened, so that the recording paper transport surface can be fully opened. ing.

FIG. 4 shows the upper housing 1 with the lid opened with respect to the apparatus main body 2.
The upper housing 1 can be opened counterclockwise with one roller shaft of the transport roller 11 as a fulcrum and held at a predetermined angle as shown in FIG.

The intermediate stacker 200, each pressure roller of each of the transport rollers 201 and 203, and the transfer belt 50 and the timing roller
13 pressure rollers, fixing roller 80 and paper discharge roller 90
Each member such as one of the rollers is disposed on a separate substrate (not shown) mounted to rotate about the support shaft S of the upper housing 1 as a fulcrum. By rotating in the direction, each of the above-described members is moved from a position indicated by a broken line to a position indicated by a solid line, whereby the conveying surface of the intermediate stacker 200 can be opened.

The rotation angle of the intermediate stacker 200 and the like is mechanically limited, and a safety mechanism is provided so that the upper housing 1 can be closed only when the respective members are returned to the positions shown by the broken lines. I have.

As is apparent from the above description, the color image forming apparatus of the present invention has various copy functions such as double-sided copy, composite copy, and manual paper feed. Therefore, the handling operation of the sheet feeding is easy, and at the same time, the transport path can be freely set, so that it is possible to configure a gentle transport path in which troubles such as a jam are unlikely to occur.

Further, since all of the mounted paper cassettes C are locked in a horizontal position, there is no danger that the paper cassettes C will move or drop even if the opening angle of the upper housing 1 is increased. The upper housing 1 can be opened until the can be easily taken out.

Further, as shown in FIG. 5 showing the upper surface of the color image forming apparatus, if the vertical paper feed unit A including the timing roller 13 is structured to be opened and closed in the horizontal direction as shown by a dashed line, Since the toner collection box 47A provided separately from the cartridge 3 can be taken out of the apparatus main body 2 together with the feeding section A, the toner collection box 47A can be enlarged accordingly.

Further, the color image forming apparatus of the present invention can have a structure in which the upper housing is opened to the back side of the apparatus main body, thereby making it possible to easily replace, for example, a toner cartridge for replenishment.

6A and 6B show the right side of the apparatus. In the case of FIG. 6A, the upper housing 1A is sufficiently opened to the apparatus main body 2A and the toner cartridge 71A connected to the supply hopper 70A is opened. This is an example configured to be pulled out upward.

FIG. 6 (B) shows a configuration in which the supply hopper 70B can be slightly tilted leftward from an upright state when not in use,
This is an example in which the toner cartridge 71B can be pulled out only by opening the upper housing 1B at a small angle.

FIG. 6C shows an example in which the toner supply section is provided on the left side, that is, on the front side of the apparatus main body 2C. In this case, the toner cartridge 71C can be easily pulled out regardless of the opening angle of the upper housing 1C. This is a possible and most desirable example.

〔The invention's effect〕

According to the present invention, a compact color image forming apparatus capable of coping with various copy functions and modes such as double-sided copy, composite copy identification paper, and insertion of separation paper is provided.

In addition, since the above-mentioned device can have a clamshell structure in which the upper housing can be opened by being divided into two while having advanced functions, it is possible to easily perform various maintenance operations including jam clearance. It is also very useful as a color image forming apparatus suitable for the image forming apparatus. That is, according to the present invention, the transfer paper fed from the transfer paper storage portion or the cassette disposed on a surface substantially horizontal to the upper housing upper surface portion is transported to the photosensitive drum transfer portion almost in close contact with the transfer belt. ,
Trouble during transfer to the photoconductor drum transfer unit in conventional U-turn paper feeding (usually, the transfer paper is folded at a steep angle and is closely attached to the transfer unit, or the paper feed speed and photoconductor speed are transferred. Jam trouble, transfer misalignment, etc. caused by conditions such as the need to synchronize when paper is closely attached)
In order to transport the transfer paper having the toner image on the lower surface by the attraction force of the transfer belt, and to transport the transfer paper having the toner image to the fixing unit by separation at the curvature portion, in the transfer of the transfer paper after the toner transfer. The lower surface can be conveyed regardless of the distance between the fixing unit and the fixing unit.Furthermore, since the transfer belt part of the upper case is separated and opened using the transfer unit, it is easy to clear the jam, and it is transferred to the upper case when replacing process cartridges. Since the paper storage cassette is opened while being held in a bag shape, the opening angle (sufficient for pulling out the drum and / or the developing process cartridge at least upward without causing the cassette or transfer paper to fall off does not occur). Conventionally up to 90
(The front and rear parts can also have an opening of 90 mm or more.) It is also possible to take advantage of the fact that it is possible to have a transfer section and its opening surface at the top using a transfer belt. The inner guide side plate in the feeding / transporting section that reaches the transfer belt without causing toner spilling from the developing section on the transfer section and transfer section, or during replacement maintenance, etc. It is possible to open the sheet integrally with the transfer belt, the transfer paper cassette, and the like, and it is possible to very easily deal with troubles such as jam processing.

As described above, according to the present invention, the feeding of the recording paper and the separation from the photosensitive member after the image transfer are carried out in the same manner as in the normal horizontal conveyance, the conveyance trouble is extremely reduced, and the cassette accommodating portion is made compact. A color image forming apparatus with excellent practicability, which can be mounted and can easily carry out jam processing or maintenance and inspection work of each process equipment, has been provided.

[Brief description of the drawings]

1, 2 and 4 are cross-sectional views of the color image forming apparatus of the present invention and the main parts thereof, FIG. 3 is a block diagram showing an image forming system, and FIG. 5 is a plan view of the apparatus. FIG. 6 is an explanatory view of each opening / closing type of the upper casing according to the present invention, and FIG. 7 is an example of another company of the two-part image forming apparatus. 1, 1A, 1B, 1C ... upper housing 2, 2A, 2B, 2C ... apparatus body 3, 3A, 3B, 3C ... process cartridge 9 ... pre-transfer charger 30 ... photosensitive drum 35 ... Charger 36, 37, 38, 39 Developing device 40 Cleaning device 47, 47A Toner collection box 50 Transfer belt 51 Transfer device 70A, 70B Supply hopper 71A, 71B Toner cartridge 200 Intermediate stackers 200A, 200B, 210A Transport guides 201, 202, 203 Transport rollers 210 Manual feeder A A Paper feeder B Laser writing unit C, CA, CB, CC Paper cassettes T1, T2, T3 ... Switching member

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor, Seiko Naganuma 2970, Ishikawacho, Hachioji-shi, Tokyo Inside Konica Corporation (72) Inventor, Masahiko 2970, Ishikawacho, Hachioji-shi, Tokyo Examiner, Konica Corporation Inside Island ▲ Junichi Saki ▼ (56) References JP-A-1-145943 (JP, A) JP-A-61-80269 (JP, A) JP-A-62-231963 (JP, A) JP-A-62-134654 (JP, A A) JP-A-1-308323 (JP, A) JP-B-55-20577 (JP, B2)

Claims (3)

(57) [Claims] A developing device group including an image carrier drum and a charger, a color toner developing device and a black toner developing device on the periphery thereof;
A cleaning device and a transfer paper transfer means,
In a color image forming apparatus capable of being opened in two parts vertically, a transfer belt is provided as a transfer conveyance means in an upper housing, and a paper feed cassette which is positioned substantially horizontally in an open state on an upper surface of the upper housing. The image forming apparatus further comprises a mounting section, a paper feeding means for separating one transfer sheet from the mounted paper feeding cassette and feeding the separated transfer paper to the transfer conveying means, and an intermediate stacker for reversing the transfer material. Color image forming apparatus. 2. The color image forming apparatus according to claim 1, wherein said intermediate stacker is located above said transfer / conveying means and below a mounting portion of said sheet cassette. 3. A process cartridge including the image carrier drum provided in a lower housing, a developing device group provided below the image carrier drum, and at least the image carrier drum and a developing device group. 3. The color image forming apparatus according to claim 1, wherein the color image forming apparatus is vertically detachable with respect to the apparatus main body in an open state.