JPH09269626A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the miniaturization of a color image forming device main body, an improvement of the operability of processing transfer paper, and the maintaining of high image quality by making the arrangement of the intermediate transfer belt of a color image forming device optimum. SOLUTION: The device forms a color image by transferring repeatedly a toner image formed on a photoreceptive belt 1 to the intermediate transfer belt 10, thereby superimposing the plurality of toner images to form a composite toner-image, and by transferring them from the surface of the intermediate transfer belt 10 to transfer paper all at once. The intermediate transfer belt 10 is arranged at an angle between rotating rollers 11 and 12, and a toner image on the photoreceptive belt 1 is transferred to the lower part of the inclined belt surface. In the lower part of the device main body is paper feed cassette 17 and in the upper part of it is a stack part, and a carrying path from a carrying roller 19, via resist roller 20 and a transfer roller 14, to a fixing device 50 is arranged almost parallel with the inclination of the intermediate transfer belt 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus such as a color copying machine, a color printer or a color facsimile having an intermediate transfer member.

[0002]

2. Description of the Related Art As a typical one of conventional color image forming apparatuses, a photosensitive drum for forming a latent image and a transfer paper are held and a toner image on the photosensitive member is transferred. A system using a transfer drum and a system transferring a plurality of toners on a photosensitive drum by superimposing them on a transfer paper have been put into practical use. In the method using a transfer drum, the transfer paper must be electrostatically or mechanically held on the transfer drum, so it is difficult to use small size paper such as postcards or thick paper as transfer paper. , Not so-called paper-free. Further, in the method of mechanically holding the front end of the transfer paper, the image cannot be transferred onto the entire surface of the transfer paper.

A method of superimposing a plurality of toner images on a photosensitive drum has also been proposed and put into practical use. In this method, a latent image is formed by recharging and exposing the surface of a photosensitive member on a previously transferred toner image. Therefore, it is difficult to maintain good charging uniformity and the image quality is inferior to the conventional transfer drum system.

In order to solve these conventional drawbacks, it is possible to achieve a paper-free property in which postcards and thick paper can be used as transfer paper, and as a system capable of achieving high-quality images, each of the colors formed on the photoreceptor is A method has been proposed in which toner images are sequentially superposed and transferred to the same position on an intermediate transfer member such as an endless belt, and the transferred images are transferred to a transfer paper to be fixed, whereby a full-color image is obtained. . However, there is a problem in the size of the machine and the jam handling operation in that the intermediate transfer belt is arranged in the main body of the apparatus while taking advantage of the paper-free property. In order to efficiently reduce the cross-sectional area of the apparatus main body, it is necessary to reduce the volume of the intermediate transfer belt body having a circumferential length that temporarily holds the entire print image area. Further, in order to make the structure of the intermediate transfer belt member as simple as possible and to reduce the cost, it is most preferable that the structure is supported by two rollers, but on the contrary, it becomes long in the roller axis direction (for example, With an apparatus that can use A3 size paper as the transfer paper, it becomes as large as about 260 mm.) In addition, when the intermediate transfer belt is arranged in the vertical direction, the apparatus main body becomes high, and when the intermediate transfer belt is laid down sideways, the depth becomes large and the transfer paper conveyance path becomes long.

In order to solve these problems, Japanese Patent Laid-Open No.
In JP-A-294673, an intermediate transfer belt is used to make the transfer paper transport path an upper transport type for downsizing, but since the paper feed cassette portion and the discharge stack portion are projected as the transport path, Miniaturization has not necessarily been achieved for the entire apparatus body.

In view of the above-mentioned problems of the prior art, the present invention achieves the downsizing of the main body of the apparatus by optimally disposing the intermediate transfer belt, improving the operability of transfer paper processing and maintaining a high color image quality. An object is to provide a forming device.

[0007]

A color image forming apparatus according to a first aspect of the present invention is an image bearing apparatus for reducing the size of a main body of the color image forming apparatus by optimally disposing an intermediate transfer belt. The toner image formed on the body is repeatedly transferred to the intermediate transfer body to form a synthetic toner image by superposing a plurality of toner images on the intermediate transfer body, and the synthetic toner image is transferred from the intermediate transfer body onto the transfer paper. In a color image forming apparatus for collectively transferring and fixing the image bearing member on one side, one belt surface of a belt-shaped intermediate transfer member laid by at least two rollers is arranged with an inclination, and the image bearing member is provided below the inclined belt surface. The image carrier is arranged to transfer the toner image of, the paper feed unit is arranged on the lower side of the apparatus main body, and the paper discharge unit is arranged on the upper side of the apparatus main body, and extends in the direction from the paper feed unit to the paper discharge unit. Transfer paper transfer The is characterized in that provided.

A color image forming apparatus according to claim 2 is
A developing roller at the developing position of the developing device for developing the electrostatic latent image formed on the image carrier to prevent the scattering of the developing toner onto the image carrier and the prevention of color mixture. And the developing device and the image bearing member are arranged with the contact position of the developing roller slightly inclined so that the contact position of the developing roller is on the lower side.

A color image forming apparatus according to claim 3 is
In order to further shorten the transfer paper transport path, a part of the transfer paper transport path is formed so as to be substantially parallel to the inclined belt surface of the intermediate transfer body.

The color image forming apparatus according to claim 4 is
A writing unit for forming an electrostatic latent image on the image carrier is provided in the lower portion of the main body of the apparatus in order to stabilize the image quality of writing by the electrostatic latent image writing unit.

A color image forming apparatus according to claim 5 is
In order to accommodate a plurality of developing unit arrangements, the image carrier is characterized in that a belt member is provided by at least two roller members.

A color image forming apparatus according to claim 6 is
In order to prevent transfer blur due to contact with the transfer roller, the synthetic toner image is transferred from the primary transfer position where the toner image formed on the image carrier is transferred to the intermediate transfer member, from the intermediate transfer member. It is characterized in that the distance on the intermediate transfer member to the secondary transfer position where the image is collectively transferred is set to the maximum image output length or more.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the color image forming apparatus of the present invention. In FIG. 1, reference numeral 1 denotes a flexible belt-shaped photosensitive member which is a belt-shaped image carrier, and the photosensitive belt 1 is installed between rotating rollers 2 and 3 and drives the rotating rollers 2 and 3. Is conveyed in the clockwise direction. 4 is a charging charger as a charging means, 5 is a laser writing system unit as an image exposing means, 6 is three developing means containing color developers of yellow, magenta and cyan, that is, a rotary color developing device, and 7 is a color developing device. It is a black developing device which is a developing means which is provided separately from the developing device 6 and which contains a black developer.

In the laser writing system unit 5, a laser beam generated by a semiconductor laser (not shown) is rotationally scanned by a polygon mirror 5B rotated by a drive motor 5A, and an optical path is bent by the mirror through an fθ lens 5C. The circumference of the photoconductor belt 1 that has been uniformly charged by the charging charger 4 as a charging unit is exposed to form an electrostatic latent image. For this reason, the laser writing system unit 5 is incorporated in the main body of the apparatus by being housed in a holding case having a slit-shaped exposure opening on the upper surface. A bottom plate (not shown) is provided above the paper feeding cassette 17 and below the writing system unit 5.
In order to support each unit, side plates of the apparatus main body are provided on the left and right in the axial direction of the roller and are attached to the bottom plate. As the laser optical system 5, in addition to the one shown in the figure, an optical system in which a light emitting portion and a converging light transmission body are integrated is also used. Charger 4, laser writing light 5
D, the photoconductor cleaning blade 15A is provided on the side of the rotating roller 2 on which the photoconductor belt 1 is installed.

Each of the color developing device 6 and the black developing device 7 is equipped with a developing roller which comes into contact with or comes into contact with the photoconductor belt 1 at a predetermined position, and the latent image on the photoconductor belt 1 is developed by non-contact or contact development. It has the function of visualizing by the method. Reference numeral 10 denotes an intermediate transfer belt, which is an intermediate transfer member. The intermediate transfer belt 10 is installed between the rotating rollers 11 and 12 while being inclined, and is conveyed counterclockwise by driving the rotating rollers 12 and 13. To be done. The inclined belt surface on the lower side of the intermediate transfer belt 10 is in contact with the photosensitive belt 1 and the intermediate transfer belt 10 at the rotating roller 3, and the first visible image on the photosensitive belt 1 is an intermediate image. By the bias brush 13 provided in the transfer belt, the image is transferred onto the intermediate transfer belt 10 (primary transfer position), and by repeating the same process, the second visible image, the third visible image,
The fourth visible images are superimposed on the intermediate transfer belt 10 and transferred without causing positional deviation. A transfer roller 14 serving as a secondary transfer member is disposed above the rotating roller 11 of the intermediate transfer belt 10 so as to contact and separate from the intermediate transfer belt 10.
Is provided. The distance on the intermediate transfer belt 10 from the primary transfer position to the secondary transfer position is set to be equal to or longer than the maximum image output length.

In the figure, reference numeral 15 is a waste toner collecting container including the cleaning blade 15A of the photosensitive belt 1, 16 is a cleaning device for the intermediate transfer belt 10, and the blade 16A of the cleaning device 16 is for the intermediate transfer belt 10 during image formation. The intermediate transfer belt 1 is kept at a position separated from the surface and is only shown at the time of cleaning after the secondary image transfer as shown in the figure.
It is pressed against the surface of 0.

FIG. 2 shows the internal structure of the color and black developing units 6 and 7, and FIG. 3 is a perspective view of the color developing unit 6. The rotary color developing device 6 includes a casing 21 which is a rotating body.
Is rotatably provided around a rotation center O, and the casing 21 can be rotated clockwise in the drawing by the drive of a drive mechanism (not shown). Also, casing 2
1 is a yellow, magenta, and cyan developing unit 22
(-Y, M, C) are integrally held. The developing units 22 (-Y, M, C) of each color have the same form and the same operation.

The photosensitive belt 1 laid between the rotating rollers 2 and 3 is arranged with the belt surface vertically or slightly inclined, and the color developing device 6 is arranged in the lower part and the black developing device 7 is arranged in the upper part in parallel. It is arranged. As described above, since the intermediate transfer belt 10 is inclined and the photosensitive belt 1 is substantially vertical, the waste toner collecting container 15 can secure a certain space.

At the developing position in the color developing device 6, the developing roller 23 rotates in the same direction as the moving direction of the photosensitive belt 1 with a predetermined linear velocity ratio with the photosensitive belt 1.
It is disposed so as to face the photoconductor belt 1. Further, below the developing roller 23, the supply roller 25 made of an elastic material such as foamed polyurethane slides on the developing roller 28 in the sliding portion and rotates in the same direction as the developing roller 23 at a predetermined linear velocity ratio. It is provided. A developing blade 26, which is a thin plate having a spring property such as stainless steel, is provided on the downstream side of the supply roller 25 in the rotation direction so that one end thereof contacts the developing roller 23.

As shown in FIG. 3, a toner accommodating portion 29 is provided on the front side of the developing device 6, and the screw-shaped first toner conveying member 27 is provided from the toner accommodating portion 29 to the color developing device 6. Arranged in parallel with the developing roller 23 and the supply roller 25 to the rear side of the developing unit 22 side plate,
The toner is conveyed from the front side to the rear side in the figure. Then, it interlocks with the developing roller 23 and the supply roller 25 and rotates with them at a predetermined linear velocity ratio. The developing unit partition plate 24 is arranged so that a part of the developing unit partition plate 24 contacts the supply roller 25.
3, the supply roller 25, etc.
A toner transport space surrounding 7 is formed. The toner supplied onto the supply roller 25 is supplied to the surface of the developing roller 23 by the supply roller 25 and charged, and the developing roller 2 is charged.
3 supported on the surface. The toner carried on the surface of the developing roller 23 is thinned by the developing blade 26 to develop the electrostatic latent image formed on the surface of the photosensitive belt 1.

By the way, the toner not used in the developing step is conveyed by the first toner conveying member 27 to the rear end portion of the developing device 6 on the side facing the toner accommodating portion 29, and the developing roller 23 and the supply roller 25. The toner reaches the toner circulating portion provided outside the effective diameter portion in the axial direction, and the toner falls below the developing unit 22 due to gravity. Development unit 22
In the lower part, a screw-shaped second toner carrying member 28 is also arranged in parallel with the developing roller 23, the supply roller 25 and the first toner carrying member 27, and is in the opposite direction to the first toner carrying member 27. The toner that has not been used in the developing process is conveyed to the toner storage unit 29 by rotating so as to convey the toner to the toner storage unit 29. By appropriately setting the toner transport amounts of the first toner transport unit 27 and the second toner transport member 28, the toner on the supply roller 25 can be detected without detecting the toner amount in the developing unit 22 or performing complicated toner supply amount control. The small color developing device 6 is capable of supplying toner, has a large degree of freedom in layout, and has a small cross-sectional occupation rate with respect to the photosensitive belt 1. The toner cartridge 30 shown in FIG. 3 is attachable to and detachable from the toner accommodating portion 29 so that the toner cartridge 30 can be replaced when replenishing the toner.

The black developing device 6 is a developing device of a type in which black toner is contained in the developing container 41, and is a developing device integrally formed as a so-called developing cartridge whose life is replaced at the end of toner. is there. Like the developing unit 22 of the color developing device 7, the developing roller 23 is connected to the photosensitive belt 1.
Is arranged facing the photosensitive belt 1 so as to rotate in the same direction as the moving direction of the photosensitive belt 1 at a predetermined linear velocity ratio. In addition, above the developing roller 23, the supply roller 25 made of an elastic material such as polyurethane foam slides on the developing roller 23 at the sliding portion and rotates in the same direction as the developing roller 23 at a predetermined linear velocity ratio. Further, a developing blade 26 made of a thin plate having a spring property such as stainless steel is provided so that one end thereof contacts the developing roller 23. The developing blade 2 is provided in the developing container 41.
6 is provided with a paddle 42 having a plurality of blade-shaped portions for agitating the toner in the vicinity of 6 and a first agitator 4 for transporting and agitating the toner to the supply roller 25 and the developing roller 23 side.
3 and a second agitator 44 are provided. Here, the type of developing cartridge containing toner is used,
Of course, a developing device of a type in which a toner cartridge is replaced and replenished like a color developing device may be used. Further, the black developing device 7 can swing horizontally with respect to the photoconductor belt 1 and moves away from the photoconductor belt 1 during non-development and approaches or contacts the photoconductor belt 1 during development.

The process cartridge 31 includes a photoconductor belt 1, a charging charger 4 and an intermediate transfer belt 1.
0, the cleaning device 16, and the registration roller 20B are integrated, and the waste toner collecting container 15 is replaceably incorporated in the process cartridge 31.
The surface of the registration roller 20B outside the case of the process cartridge 31 also has a function as a conveyance guide.

Here, the waste toner scraped by the cleaning blade 16A from the intermediate transfer belt 10 is
The auger 16B provided in the cleaning device 16 conveys the toner in the front direction of the cross section, and further conveys it to the waste toner collecting container 15 by a conveyance member (not shown) provided on the front side surface of the process cartridge 31, and collects it. As a result, the waste toner can be collected without replacing the process cartridge 31, so that the life of the process cartridge can be extended.

The transport path to the transport roller 19, the registration roller 20, the transfer roller 14, and the fixing device 50 is arranged substantially in parallel with the inclined belt surface of the intermediate transfer belt 10 in order to reduce the size of the apparatus main body.

An image forming process by the above-mentioned color image forming apparatus is performed as follows. First, the formation of a multicolor image is performed according to the image forming system described below.
That is, the image data processing unit arithmetically processes the data obtained by the color image data input unit in which the image sensor scans the original image to create image data, which is temporarily stored in the image memory. Then, the image memory is taken out at the time of recording and is inputted to a recording unit, for example, a color image forming apparatus shown in the apparatus 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 5, a laser beam generated by a semiconductor laser (not shown) in the laser writing system 5 is generated. On the circumference of the photoreceptor belt 1 which is rotationally scanned by the polygon mirror 5B rotated by the drive motor 5A, has its optical path bent by the mirror through the fθ lens 5C, and is uniformly charged beforehand by the charging charger 4 as a charging means. To form an electrostatic latent image.

Here, the image pattern to be exposed is a monochromatic image pattern when a desired full-color image is separated into yellow, magenta, cyan, and black. The formed electrostatic latent images of the three colors are developed by the rotary operation of the rotary color developing device 6 so that the yellow, magenta, and cyan developing units are sequentially opposed to the photoreceptor belt 1 to be developed, and are made into a monochromatic color. A monochromatic image is formed (at this time, the black developing device 7 is retracted to the non-developing position with respect to the photoconductor belt 1), and the black electrostatic latent image is developed by the black developing device 7 and is visualized. A single color image is formed by colorizing and monochromeizing. The monochromatic image formed on the photoconductor belt 1 is sequentially superimposed and transferred onto the intermediate transfer belt 10 that rotates counterclockwise while contacting the photoconductor belt 1. The yellow, magenta, cyan, and black images that are superimposed on the intermediate transfer belt 10 are conveyed from the paper feed cassette 17 to the transfer portion via the paper feed roller 18, the conveyance roller 19, and the registration roller 20, and the transfer roller 14 is intermediate. The rotating roller 11 of the transfer belt is brought into contact with the transfer roller through the transfer paper and transferred. At this time, when the transfer roller 14 comes into contact with the transfer roller 14, it has passed through the image trailing edge primary transfer portion on the intermediate transfer belt as described above. After the transfer is completed, the transfer paper is fixed by the fixing device 50 to complete a full-color image.

Next, the structure of the apparatus body will be described with reference to FIGS. The main body structure of the apparatus is composed of a main body frame 9 which is a stationary casing and a front frame 8 which is a front casing in which a transfer paper transport path can be opened. A paper feeding cassette 17 is arranged below the main body frame 9. The developing device and the process cartridge are replaceably arranged in the central portion, and the fixing device 50 is arranged above the developing device and the process cartridge to form a paper discharge stack portion.

The front frame 8 is supported so as to be rotatable about a rotation support shaft 9A provided on a main body frame 9 serving as a rotation fulcrum, and at the time of image formation output, as shown in FIG. It is held by the frame 9. By releasing the holding during the jam processing, it becomes possible to open in the clockwise direction, and the open state can be maintained by the power of the tension spring or the like. The front frame 8 holds a registration roller 20A, a transfer roller 14 and the like, which are a part of the conveyance path. As a result, when the front frame 8 is opened, as shown in FIG.
As shown in, the conveyance path is opened and the paper jam processing is performed. At this time, only jam processing can be performed without operating the image forming system unit, so that there is no problem such as toner loss.

Further, the main body frame 9 holds a process cartridge 31 in a structure described later, and an intermediate member supported so as to be rotatable about a rotation support shaft 9B provided on the main body frame 9 serving as a rotation fulcrum. The frame 40 is shown in FIG.
It is provided on the left and right as shown in. Intermediate frame 40
Is normally held by the main body frame 9 (except when the process cartridge and each developing device are replaced), and can be opened in the clockwise direction by releasing the holding.

FIG. 6 shows the attachment / detachment position of the process cartridge 31, and FIG. 7 shows the attachment / detachment state of the process cartridge 31. Rail-shaped projections 32 are provided on both side surfaces of the process cartridge 31 so as to be parallel to the attachment / detachment operation direction.
Corresponding to this, the intermediate frame 40 is also provided with a rail-shaped groove 40A that is parallel to the attachment / detachment operation direction. Therefore, the process cartridge 31 is held by the intermediate frame 40 during mounting. Also, the intermediate frame 4
When the process cartridge 31 is operated in the direction of the arrow while 0 is supported and fixed at the position shown in FIG. 6, the process cartridge 31 can be easily attached to and detached from the intermediate frame 40. In particular, the handle 33 is attached to the end of the process cartridge 31.
By providing, the operability is further increased. As for the shape of the groove 40A, if the insertion side of the process cartridge 31 is opened like a trumpet, a slight deviation can be mounted without any problem.

Here, the operation direction of the process cartridge 31 is the direction in which the two rollers of the intermediate transfer belt 10 are stretched, and the stretched belt surface of the photosensitive belt 1 is with respect to the intermediate transfer belt surface. Since they are arranged so as to be substantially parallel to each other, the space between development and transfer can be narrowed and the cross section of the apparatus main body can also be reduced.

The intermediate frame 40 can be further opened with respect to the attachment / detachment position of the process cartridge 31, and reaches the same position as the opened position of the front frame as shown in FIG. By supporting and fixing the intermediate frame 40 while mounting the process cartridge at this position, the developing units 6 and 7 arranged on the back side of the process cartridge can be made large without temporarily retracting the process cartridge to the outside of the apparatus main body. Since it is opened, the attachment / detachment operability of the developing devices 6 and 7 is good.

Here, as an example of a mechanism for supporting and fixing the intermediate frame 40 in two stages, as shown in FIG. 7, two grooves are provided on the lower side of the rotation fulcrum of the intermediate frame 40, and the leaf spring 34 is shown in FIG. It is built into the main body frame so that it swings in the direction of the arrow with a constant spring force. The swinging tip portion 34A of the leaf spring 34 is rotated by the intermediate frame 40 so that the groove 40
Corresponding to B and C, the intermediate frame 40 is latched, supported and fixed in two stages by entering. At this time, the process cartridge 31 is supported and fixed at a position in the attachment / detachment rotation direction such that the gravity center position G of the process cartridge is substantially on the vertical line of the rotation center position of the intermediate frame 40, and the attachment / detachment movement direction is made on the substantially vertical line. By adjusting the positions of the handles as described above, the spring force of the leaf spring 34 for supporting and fixing the process cartridge is small, the stability during rotation of the intermediate frame 40 is stable, and the process cartridge is not gravitationally unbalanced. It can be operated without falling into a stable state. In addition, if the intermediate frame 40 is used as a stopper member for stopping rotation by using a part of the front frame at the second support fixing position, the groove 40C of the intermediate frame 40 can be eliminated.

FIG. 9 is a sectional view showing another embodiment of the color image forming apparatus according to the present invention. This embodiment is different from the previous embodiment in that a photosensitive drum 1'is used instead of the photosensitive belt, and the developing unit is a rotary developing device 6'in which all four colors are integrated. Since the photoconductor drum 1'is used, the developing space is narrower than that in the previous embodiment. Therefore, the developing position is set to one place by using the four-color rotary developing device 6 '. As shown in the drawing, even if toner is scattered from the developing roller 23 due to the contacting / separating operation of the developing roller 23, the developing position is set at a position below which the photoconductor surface does not exist. Then, the toner cartridges of the respective colors of the rotary developing device 6 ′ are arranged outside the transfer paper transport path, so that the toner cartridges can be replaced regardless of the process cartridges. Note that the other configurations and operations are almost the same as those in the above-described embodiment, and thus the description thereof will be omitted.

[0036]

As described above, in the color image forming apparatus according to the first aspect of the present invention, since the intermediate transfer belt is obliquely arranged and the lower paper is fed and the upper paper is ejected, the main body of the apparatus has a proper balance. The transport path from the paper feed section to the paper discharge section can be shortened, the transport quality can be stabilized, and the transfer paper transport path can be opened on the front side of the machine body for jam processing. Therefore, it is possible to easily understand the jam processing operation, and it is possible to perform only the jam processing without operating the image forming system unit, and it is possible to eliminate problems such as toner loss.

In the color image forming apparatus according to the second aspect of the present invention, for example, in the belt-photosensitive-surface contact developing method, even if toner is scattered from the developing roller due to the contacting / separating operation of the developing roller, there is no photosensitive surface below. In addition to the common effects described above, there is an effect that the photoconductor can be prevented from adhering to it, so that a color image without color mixture can be obtained.

In the color image forming apparatus according to the third aspect of the present invention, by providing the transfer paper conveying path substantially parallel to the surface of the intermediate transfer belt, in addition to the common effects described above, the front surface of the apparatus main body can be made thin, and There is an effect that the size can be reduced and the transportation route can be simplified and shortened.

In the color image forming apparatus according to the fourth aspect, since the writing unit is provided at the lower portion of the main body of the apparatus, in addition to the common effects described above, the main body of the apparatus is immovable rather than the movable section casing for jam clearance, unit replacement, and the like. This has the effects that it can be firmly assembled and fixed to the case body, color misregistration at the time of a color image due to vibration or the like can be prevented, and positioning with the side plate supporting the photoconductor reference axis can be performed accurately.

In the color image forming apparatus according to the fifth aspect, by using the image carrier as a belt, in addition to the above-mentioned common effects,
The unit can be made thinner, the device body can be downsized, and
Since the belt surface between the rollers can be long and the belt surface is vertical or slightly inclined, there is an effect that a plurality of developing units can be arranged in parallel to the belt surface without worrying about color mixture of developing toner on the photoconductor. Also, tilt the intermediate transfer belt,
Since the photoconductor belt is almost vertical, there is also an effect that a space for the capacity of the waste toner collecting container can be secured.

A color image forming apparatus according to claim 6 is
Since the distance on the intermediate transfer member from the secondary transfer position to the secondary transfer position is equal to or longer than the maximum image output length, in addition to the common effect described above, contact of the transfer roller with the intermediate transfer belt causes the intermediate transfer belt to move at a high speed. Even if it fluctuates, the transfer blur of the toner image on the photoconductor and the intermediate transfer belt can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a color image forming apparatus of the present invention.

FIG. 2 is a cross-sectional view showing an internal configuration of a color and black developing device of the color image forming apparatus of FIG.

FIG. 3 is a perspective view of a color developing device of the color image forming apparatus of FIG.

FIG. 4 is a cross-sectional view of the color image forming apparatus of FIG. 1 with a front frame opened.

FIG. 5 is a perspective view of a process cartridge and an intermediate frame for supporting the process cartridge.

FIG. 6 is a cross-sectional view showing an attachment / detachment position of a process cartridge.

FIG. 7 is a side view showing a detached state of the process cartridge.

FIG. 8 is a sectional view of an intermediate frame in an open state.

FIG. 9 is a sectional view showing another embodiment of the color image forming apparatus of the present invention.

[Explanation of symbols]

 1 Photoconductor belt 1'Photoconductor drum 2, 3 Rotating roller 4 Charging charger 5 Laser writing system unit 6 Color developing device 6'Rotary developing device 7 Black developing device 8 Front frame 9 Body frame 10 Intermediate transfer belt 11, 12 Rotating roller 13 Bias brush 14 Transfer roller 15 Waste toner collection container 16 Intermediate transfer belt cleaning device 17 Paper feeding cassette 18 Paper feeding roller 19 Conveying roller 20 Registration roller 21 Casing 22 Color developing unit 23 Developing roller 24 Partition plate 25 Supplying roller 26 Developing Blade 27 First Toner Conveying Member 28 Second Toner Conveying Member 29 Toner Housing 30 Color Toner Cartridge 31 Process Cartridge 32 Rail Protrusion 33 Handle 34 Leaf Spring 40 Intermediate Frame 41 Developing Container 42 Paddle 43 First agitator 44 Second agitator 50 Fixing device

Claims (6)

[Claims] 1. A toner image formed on an image bearing member is repeatedly transferred to an intermediate transfer member, and a plurality of toner images are superposed on the intermediate transfer member to form a synthetic toner image. In a color image forming apparatus for collectively transferring and fixing the above synthetic toner image onto a transfer sheet, one belt surface of a belt-shaped intermediate transfer member which is laid by at least two rollers is arranged with an inclination, and the inclined belt surface The image carrier is arranged below the image carrier to transfer the toner image on the image carrier, the paper feed unit is arranged on the lower side of the apparatus main body, and the paper discharge unit is arranged on the upper side. A color image forming apparatus characterized in that a transfer paper conveying path extending in a direction to reach a paper section is provided. 2. The contact position of the developing roller at the developing position of the developing device for developing the electrostatic latent image formed on the image bearing member to the image bearing member is vertical or the contact position of the developing roller. 2. The color image forming apparatus according to claim 1, wherein the developing device and the image carrier are arranged so as to be slightly inclined so as to face downward. 3. The color image forming apparatus according to claim 1, wherein a part of the transfer paper conveying path is formed so as to be substantially parallel to the inclined belt surface of the intermediate transfer member. 4. A color image forming apparatus according to claim 1, wherein a writing unit for forming an electrostatic latent image on the image carrier is provided at the bottom of the apparatus main body. 5. The color image forming apparatus according to claim 1, wherein the image carrier comprises a belt member provided by at least two roller members. 6. A secondary transfer for collectively transferring the synthetic toner image onto a transfer paper from the intermediate transfer body from a primary transfer position where the toner image formed on the image bearing body is transferred to the intermediate transfer body. 6. The color image forming apparatus according to claim 1, wherein the distance to the position on the intermediate transfer member is equal to or greater than the maximum image output length.