JP2003156984A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the replacement of consumables and also to facilitate the maintenance of a fixing device itself and the elimination of paper jamming around a transfer belt and in the periphery of a fixing device. SOLUTION: In this image forming apparatus, image forming stations Y, M, C and K where an electrifying means 19 and a developing means 20 are arranged around an image carrier 17 are provided along the transfer belt 14 for every color and the transfer belt and the respective image forming stations are disposed in an oblique direction or a perpendicular direction. The image forming apparatus is equipped with a housing main body 2 where the respective image forming stations and the transfer belt are disposed at inside and a first turning part 3 and a second turning part 50 attached to the housing main body so as to be freely turnable, and a paper feeding means 11 and a fixing means 40 are disposed at the first turning part, and at least any one of a developing means 20, the image carrier 17 and the transfer belt 14 is disposed at the second turning part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an image forming station having a charging means and a developing means around an image carrier for each color along a transfer belt, and the transfer belt is passed through each station. The present invention relates to a tandem image forming apparatus that forms an image.

[0002]

2. Description of the Related Art The above-mentioned tandem type image forming apparatus is roughly classified and a plurality of image forming stations are arranged in a row.
The recording paper is electrostatically attracted to the conveyor belt, and the recording paper is sequentially brought into contact with each station while being conveyed, and electrostatic transfer force is applied between the station and the recording paper to record a toner image of a plurality of colors. A paper transport method that overlays colors while directly transferring to paper, and multiple image forming stations are arranged in rows.
While the intermediate transfer belt made of a dielectric material is brought into contact with each station and conveyed, the toner image formed at each station is sequentially primary-transferred by applying electrostatic transfer force between the station and the intermediate transfer belt. Then, two types of methods are employed: an intermediate transfer method in which colors are superposed on the intermediate transfer belt, and then secondary transfer is collectively performed from the intermediate transfer belt to the recording paper.

The above-mentioned paper transport system requires means (rollers and brushes) for attracting the recording paper to the transport belt and a high-voltage power supply, but the intermediate transfer system does not require these means and power supply. In the paper transport method, it is necessary to strictly control the transfer bias applied to each image transfer section according to the size, thickness, and type of recording paper, but in the intermediate transfer method, resistance is applied regardless of these factors of the recording paper. The primary transfer of the toner image is performed on the intermediate transfer belt having a constant thickness, surface roughness, and then the secondary transfer is collectively performed on the recording paper. It suffices to manage the transfer conditions as described above, and therefore the intermediate transfer method has many advantages.

On the other hand, when categorized by the arrangement method of each image forming station, there are a method of arranging each station in a horizontal direction and a method of arranging each station in a vertical direction (for example, Japanese Patent Laid-Open No. 9-281769). Has a drawback that the installation area is large, and the latter has a drawback that the height of the device is high and it is difficult to install it on a desk.

Therefore, conventionally, Japanese Patent Laid-Open No. 11-9552
No. 0 and Japanese Patent Laid-Open No. 8-305115, a method is known in which image forming stations are arranged in an oblique direction.

[0006]

However, in the above-mentioned conventional method, the image forming stations may be arranged vertically or obliquely in order to make the apparatus compact. The issue is the location of the fixing device. This is because if heat or vibration generated from the fixing device is transmitted to the exposure device, the transfer belt, or the image forming device, the image quality is deteriorated. It is also important that the fixing device itself be maintained and that paper jams around the fixing device be easily removed.

Further, it is also an important subject to make it possible to easily perform paper jam around the transfer belt and exchange of consumables such as an image carrier and a developing means. Regarding this point, conventionally, according to Japanese Patent Laid-Open No. 2001-142378, the transfer belt is rotated to the outside of the main body of the apparatus so that the consumables can be replaced. There is a problem that it is difficult to easily remove a paper jam around the fixing device.

The present invention solves the above-mentioned conventional problems. In an image forming apparatus in which image forming stations are arranged in an oblique direction or a vertical direction, consumables can be easily replaced, and An object of the present invention is to provide an image forming apparatus capable of easily performing maintenance of the fixing device itself and removing paper jam around the transfer belt and around the fixing device.

[0009]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention has an image forming station in which a charging means and a developing means are arranged around an image carrier and a transfer belt. An image forming apparatus in which each transfer belt and each image forming station are provided in an oblique direction or a vertical direction, provided for each color along with a housing main body in which each image forming station and the transfer belt are disposed, A first rotating part and a second rotating part which are rotatably mounted on the housing body, and a paper conveying means and a fixing means are arranged in the first rotating part,
At least one of a developing unit, an image carrier and a transfer belt is disposed in the second rotating unit, and the invention according to claim 2 is the first rotating unit in claim 1. And the rotation fulcrum of the second rotation portion is provided in the lower portion of the housing main body, and the invention according to claim 3 is characterized in that in claim 1, the first rotation portion and the second rotation portion are provided.
The rotation fulcrum of the rotation part is provided on the side of the housing main body, and the invention according to claim 4 is characterized in that in claim 1, the transfer belt is a paper transport belt. According to a fifth aspect of the present invention, in the first aspect, the transfer belt is an intermediate transfer belt, and the sixth aspect of the invention is that in the fifth aspect, the image forming stations are arranged in an oblique direction. The image carrier of each image forming station is disposed so as to abut on the belt surface of the intermediate transfer belt facing downward in the transport direction. The driven roller of the intermediate transfer belt is disposed obliquely above the drive roller, and the drive roller and the secondary transfer roller form a secondary transfer portion. The fixing means is disposed obliquely above the belt surface of the intermediate transfer belt which is upward in the conveying direction. According to a tenth aspect of the invention, in the image forming apparatus according to the sixth aspect, the first rotating unit is provided with a separation / contact unit of a secondary transfer roller that separates / contacts the intermediate transfer belt. The rotation fulcrum of the second rotation portion is provided in the lower portion of the housing body, and the driven roller of the intermediate transfer belt is disposed obliquely above the drive roller and is disposed in the second rotation portion. An image carrier and a transfer belt of each color, a belt drive gear that drives the drive roller, an image carrier drive gear that meshes with the belt drive gear to drive the image carrier of each color, and an image carrier drive of each color A relay gear meshed between the gears, A drive motor provided on the housing main body side and disposed on the most upstream side of the belt surface facing downward in the transport direction; and a transmission gear meshed with the drive motor and the most upstream image carrier driving gear. The invention according to claim 11 is characterized in that in claim 10,
13. The invention according to claim 12, wherein the transmission gear and the most upstream side image carrier driving gear mesh with each other in a rotation normal direction when the second rotating portion is rotated. 11. The apparatus according to claim 10, wherein the transmission gear and the most upstream side image carrier driving gear mesh with each other in a rotational tangential direction when the second rotating portion is rotated.
According to a third aspect of the present invention, in the image forming apparatus according to the sixth aspect, the fulcrum of rotation of the first rotating portion and the second rotating portion is provided at a lower portion of the housing body, and the driving roller of the intermediate transfer belt is provided. Is an image carrier and a transfer belt of each color, which are disposed obliquely above the driven roller and are disposed on the second rotating portion, a belt drive gear for driving the drive roller, and the belt drive gear. An image carrier driving gear that meshes with each other to drive the image carrier of each color, a relay gear that meshes between the image carrier driving gears of each color, and a most upstream side of the belt surface that is provided on the housing body and faces downward in the transport direction. An invention according to claim 14 is characterized in that: the image forming apparatus according to claim 6, further comprising: a drive motor provided; and a transmission gear meshed with the drive motor and a belt drive gear. 1 rotation part and The rotation fulcrum of the rotation unit is provided in the lower part of the housing body, the driven roller of the intermediate transfer belt is disposed obliquely above the drive roller, and the driven roller of each color is disposed in the second rotation unit. Between the image carrier and the transfer belt, the belt drive gear that drives the drive roller, the image carrier drive gear that meshes with the belt drive gear and drives the image carrier of each color, and the image carrier drive gear of each color A relay gear to be meshed, a drive motor provided on the housing main body side, disposed on the most downstream side of the belt surface facing downward in the transport direction, and a transmission gear meshed with the drive motor and the belt drive gear. Is characterized by.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 16 show one embodiment of the image forming apparatus of the present invention, FIG. 1 is a schematic sectional view showing the entire structure, FIG. 2 is an enlarged view of the transfer belt and the image forming unit of FIG. 1, and FIG. Is an enlarged view of the exposure means of FIG.
FIG. 4 is an enlarged view of the paper conveying means in FIG. 1, FIG. 5 is a front view seen from the right in FIG. 1, and FIG. 6 is a schematic cross-sectional view showing a state in which the first rotating portion is opened in FIG. FIG. 7 is a diagram for explaining a modified example of the embodiment of FIG. 6, FIG. 8 is a schematic cross-sectional view showing a state in which the second rotating portion is opened following FIG. 6, and FIG. 9 is a consumable item in FIG. FIG. 10 is a diagram for explaining the modification of the embodiment of FIG. 8, FIG. 11 is a diagram for explaining the replacement of consumables in FIG. 10, and FIG. FIG. 13 to FIG. 16 are perspective views of the transfer belt and the image carrier, and FIGS. 13 to 16 are views for explaining an example of the drive transmission system of the image carrier in FIG.

Regarding the same structure between the drawings,
The same numbers may be given and the description may be omitted. The present embodiment is an example of the above-mentioned intermediate transfer method.

Referring to FIG. 1, an image forming apparatus 1 of the present embodiment includes a housing body 2, a first rotating portion (door body) 3 mounted on the front surface of the housing body 2 so as to be openable and closable, and a first rotating portion.
Paper discharge tray (paper discharge unit) 3 formed on the upper part of the rotating unit 3
a, a control unit 4, a power supply unit 5, an exposure unit (exposure unit) 6, an image forming unit 7, a cooling unit 8 including a blower fan, a transfer belt unit 9, and a sheet feeding unit. The unit 10 is arranged, and the paper conveying means 11 is arranged in the first rotating portion 3.
The consumables in the image forming unit 7 and the paper feeding unit 10 are configured to be attachable to and detachable from the main body. In that case, the configuration including the transfer belt unit 9 can be removed for repair or replacement. It has become.

The transfer belt unit 9 includes a drive roller 12 disposed below the housing body 2 and rotated by a drive source (not shown), and a driven roller 13 disposed obliquely above the drive roller 12. The driven roller 13 and the intermediate transfer belt 14 are provided with an intermediate transfer belt 14 which is stretched between rollers of a book and is driven to circulate in the direction of the arrow (counterclockwise direction) and a cleaning unit 15 which contacts the surface of the intermediate transfer belt 14. The belt 14 is arranged in a direction inclined to the left side in the drawing with respect to the drive roller 12. As a result, when the intermediate transfer belt 14 is driven, the belt surface 14a in which the belt conveying direction X faces downward is located below, and the belt surface 14b in which the conveying direction faces upward is located above. In the present embodiment, the belt surface 14a is a belt tension surface (image pulled by the drive roller 12) when the belt is driven, and the belt surface 14b is a belt slack surface when the belt is driven.

The drive roller 12 also serves as a backup roller for a secondary transfer roller 39 described later. As shown in FIG. 2, the peripheral surface of the driving roller 12 has a thickness of about 3 mm,
A rubber layer 12a having a volume resistivity of 10 ⁵ Ω · cm or less is formed, and by being grounded via a metal shaft,
It is used as a conductive path of the secondary transfer bias supplied through the secondary transfer roller 39. By thus providing the driving roller 12 with the rubber layer 12a having high friction and shock absorption, it is difficult for the shock when the recording medium enters the secondary transfer portion to be transmitted to the intermediate transfer belt 14, resulting in deterioration of image quality. Can be prevented.

Further, in this embodiment, the diameter of the drive roller 12 is smaller than the diameter of the driven roller 13. As a result, the recording paper after the secondary transfer can be easily separated by the elastic force of the recording paper itself. Further, the driven roller 13 is also used as a backup roller of the cleaning means 15 described later.

The cleaning means 15 is provided on the belt surface 14a side facing downward in the transport direction. As shown in FIG. 2, a cleaning blade 15a for removing the toner remaining on the surface of the intermediate transfer belt 14 after the secondary transfer,
The cleaning blade 15a is provided with a toner conveying member 15b for conveying the collected toner, and the cleaning blade 15a is in contact with the intermediate transfer belt 14 at a portion where the intermediate transfer belt 14 is wound around the driven roller 13.

Further, on the back surface of the intermediate transfer belt 14, a primary transfer member 16 composed of a leaf spring electrode is provided so as to face an image carrier 17 of each of image forming stations Y, M, C and K which will be described later.
Is abutted by its elastic force, and a transfer bias is applied to the primary transfer member 16.

The image forming unit 7 includes image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (black) for forming a plurality of (four in this embodiment) different color images. 2), as shown in detail in FIG. 2, each of the image forming stations Y, M, C, and K has an image carrier 17 composed of a photosensitive drum and an image carrier 1 respectively.
7 is provided with a charging unit 19 and a developing unit 20 which are arranged around the periphery 7 and are composed of a corona charging unit. The image forming stations Y, M, C, K may be arranged in any order.

The image forming stations Y, M,
The C and K image carriers 17 are brought into contact with the belt surface 14a of the intermediate transfer belt 14 which faces downward in the conveying direction, and as a result, the respective image forming stations Y, M, C and K are also moved relative to the drive roller 12. It is arranged in a direction inclined to the left side in the figure. The image carrier 17, as shown by the arrow in the figure,
The intermediate transfer belt 14 is rotationally driven in the conveying direction. The intermediate transfer belt 14 may be arranged in a direction inclined to the right side in the figure with respect to the drive roller 12. In that case,
The belt conveying direction X is the opposite direction, and the belt surface facing downward in the conveying direction is 14b.

Next, the charging means 19 will be described in detail by taking the image forming station C of FIG. 2 as an example. The developing means 20 includes a developing roller exposing portion 20 near the developing roller 33.
a is formed, on the other hand, the corona charging means 19 which is a charging means is provided with an opening 1 facing upward facing the image carrier 17.
9a is formed. At this time, the developing roller exposing portion 2
0a below the corona charging means 19 upward opening 19a
When the position is positioned, toner spills from the developing roller exposed portion 20a due to gravity, enters the corona charging means 19 through the upward opening 19a of the corona charging means 19, and stains the corona charging means 19.

Therefore, in the present embodiment, the upward opening 19a is provided on the intermediate transfer belt 14 side so that the upward opening 19a of the corona charging means 19 does not overlap the developing roller exposed portion 20a of the developing means 20. I am trying to offset it. As a result, the developing roller exposing portion 2
It is possible to solve the problem that the toner spills from 0a due to gravity, enters the corona charging means 19 through the upward opening 19a, and stains the corona charging means 19.

The exposing means 6 is arranged in a space formed obliquely below the image forming unit 7 arranged obliquely, and the control unit 4 and the power supply unit 5 are arranged in the space above the exposing means 6. Has been done. Further, a paper feeding unit 10 is arranged at the bottom of the housing body 2 below the exposure means 6. Control unit 4 and power supply unit 5
Is disposed adjacent to the exposure means 6, so that the installation space can be made smaller than in the case where these are arranged in parallel with the frame that supports the device components.

As shown in FIGS. 1 and 3, the exposure means 6
Has a case 18. The case 18 is disposed in a space formed obliquely below the belt surface 14a facing downward in the transport direction, and the inclined surface 18a of the case 18 is parallel to the belt surface 14a. At the bottom of the case 18, a single scanner means 21 including a polygon mirror motor 21a and a polygon mirror 21b is arranged, a single f-θ lens 22 and a reflection mirror 23 are arranged, and further, reflection is performed. Above the mirror 23, the scanning optical paths y, m, c, k of the respective colors are provided.
So as to be parallel to the inclined surface 18a (belt surface 14a), the four folding mirrors 2 are arranged in the scanning optical paths y, m, c, k.
4 is provided, and three folding mirrors 25 are arranged in the scanning optical paths m, c, k so that the scanning optical paths y, m, c, k reflected by the folding mirror 24 are irradiated to the image carrier 17. I have set up.

By providing the folding mirrors 24 and 25 in this manner, the scanning optical paths y, m, c, and k can be bent, and the height of the case 18 can be reduced, thereby achieving compactness. In addition, each image forming station Y,
The folding mirrors 24 and 25 are arranged so that the scanning optical path lengths of the M, C, and K to the image carrier 17 are the same.

In the exposure means 6 having the above structure,
The image signal corresponding to each color from the polygon mirror 21b
The light is modulated and formed based on a common data clock frequency, and is emitted, and then passes through the f-θ lens 22, the reflection mirror 23, and the folding mirrors 24 and 25 to the image carrier 17 of each image forming station Y, M, C, K. It is illuminated and a latent image is formed.

In this embodiment, by arranging the scanning optical system below the apparatus, the vibration of the scanning optical system due to the vibration given to the frame supporting the apparatus by the drive system of the image forming means can be minimized. It is possible to prevent deterioration of image quality. In particular, the scanner means 21 is installed in the case 1
By arranging at the bottom of 8, the polygon motor 21a
The vibration applied to the entire case 18 by itself can be minimized, and the deterioration of the image quality can be prevented. Also,
By making the number of the polygon motors 21a that are the vibration sources one, it is possible to minimize the vibration applied to the entire case 18.

On the side surface of the housing body 2, a cooling means 8 composed of a blower fan is provided, and the outside air is introduced in the direction of the arrow shown in the figure to cool the exposure means 6, the control unit 4 and the power supply unit 5. . Air introduced into the apparatus from the rear of the recording sheet P in the conveyance direction or the width direction of the recording sheet P in the conveyance direction is guided to the vicinity of the polygon motor 21a, further guided to the control unit 4 and the power supply unit 5, and then outside the apparatus. Since the cooling passage is formed, the temperature rise of the polygon motor 21a is suppressed, image quality deterioration is prevented, and the life of the polygon motor 21a is extended.

Next, the details of the developing means 20 will be described with reference to FIG.
The image forming station Y will be described as a representative. In the present embodiment, the image stations Y, M, C, and K are arranged in an oblique direction, and the image carrier 17 is in contact with the belt surface 14a of the intermediate transfer belt 14 facing downward in the transport direction. The toner storage container 26 is arranged obliquely downward. Therefore, the developing unit 20 has a special configuration.

That is, the developing means 20 includes a toner storage container 26 for storing toner (hatched portion in the figure) and a toner storage portion 27 formed in the toner storage container 26.
And the toner stirring member 2 disposed in the toner storage unit 27.
9, a partition member 30 formed in the upper part of the toner storage portion 27, a toner supply roller 31 disposed above the partition member 30, and a toner supply roller 31 provided on the partition member 30 and abutting against the toner supply roller 31. The flexible blade 32 includes a developing roller 33 arranged to come into contact with the toner supply roller 31 and the image carrier 17, and a regulation blade 34 brought into contact with the developing roller 33.

The image carrier 17 is rotated in the conveying direction of the intermediate transfer belt 14, and the developing roller 33 and the supply roller 31 are used.
Is rotationally driven in the direction opposite to the rotational direction of the image carrier 17, while the stirring member 29 is rotationally driven in the direction opposite to the rotational direction of the supply roller 31. The toner stirred and carried up by the stirring member 29 in the toner storage unit 27 is supplied to the toner supply roller 31 along the upper surface of the partition member 30, and the supplied toner is rubbed against the flexible blade 32 and supplied. It is supplied to the surface of the developing roller 33 by the mechanical adhesive force to the uneven surface portion of the roller 31 and the adhesive force due to the electric power of friction. The toner supplied to the developing roller 33 is regulated by the regulating blade 34 into a coating layer having a predetermined thickness, and the thinned toner layer is conveyed to the image carrier 17 and is developed by the developing roller 33 and the image carrier 17.
The image carrier 1 at and around the nip portion formed by the contact
The latent image portion 7 is developed.

In the present embodiment, the developing roller 33, the toner supply roller 31, and the contact portion between the developing roller 33 and the regulating blade 34 on the side facing the image carrier 17 are not buried in the toner in the toner storage portion 27. I am trying. With this configuration, it is possible to prevent fluctuation of the contact pressure of the regulation blade 34 with respect to the developing roller 33 due to the reduction of the stored toner, and the excess toner scraped off from the developing roller 33 by the regulation blade 34 falls into the toner storage portion 27. Therefore, the filming of the developing roller 33 can be prevented.

Further, the contact portion between the developing roller 33 and the regulating blade 34 is located below the contact position between the supply roller 31 and the developing roller 33, and the supply roller 31 causes the developing roller 3 to move.
3 is provided to the toner storage portion 27 below the developing means, and the excess toner that has not been transferred to the developing roller 33 and the excess toner that has been regulated and removed from the developing roller 33 by the regulation blade 34 is provided. The toner returned to is agitated with the toner in the toner storage portion 27 by the agitating member 29, and is again supplied to the toner introducing portion near the supply roller 31 by the agitating member 29. Therefore, the surplus toner is dropped to the lower portion without being jammed in the rubbing portion between the supply roller 31 and the developing roller 33 or the contact portion between the developing roller 33 and the regulating blade 34 to stir the toner in the toner storage portion 27. It is possible to prevent the deterioration of the toner in the developing means from gradually progressing and to cause a sudden change in image quality immediately after the replacement of the developing means.

Returning to FIG. 1, the paper feeding unit 10 comprises a paper feeding cassette 35 in which recording media P are stacked and held, and a pickup roller 36 which feeds the recording media P one by one from the paper feeding cassette 35. It has a paper feed section.

The paper conveying means 11 is a pair of registration rollers 37 that regulates the timing of feeding the recording medium P to the secondary transfer portion.
A secondary transfer roller 39 as a secondary transfer means that is pressed against the drive roller 12 and the intermediate transfer belt 14, a recording paper conveyance path 38, a fixing means 40, and a discharge roller pair 41.
It can be said that the double-sided printing conveyance path 42 is provided.

The fixing means 40 includes a heating element such as a halogen heater in at least one of the fixing means 40 and is rotatable with respect to the fixing roller pair 4.
0a and pressing means for pressing at least one roller of the fixing roller pair 40a to the other side to press the secondary image secondarily transferred to the sheet material onto the recording medium P. The secondary image secondarily transferred to the fixing roller pair 40a
The toner is fixed on the recording medium at a predetermined temperature in the nip portion formed by. In the present embodiment, the fixing unit 40 is arranged in a space formed diagonally above the belt surface 14b that is upward in the conveying direction of the transfer belt, in other words, in a space on the opposite side of the transfer belt from the image forming station. This makes it possible to reduce heat transfer to the exposure unit 6, the intermediate transfer belt 14, and the image forming unit, and to reduce the frequency of color misregistration correction operation for each color. In particular, the exposure unit 6 is located at the farthest position from the fixing unit 40, and the displacement of the scanning optical system component due to heat can be minimized, and the color shift can be prevented.

Next, referring to FIGS. 4 to 6, the paper conveying means 11 will be described.
The detailed structure of will be described. 4 and 6, FIG.
The paper feed section 10a including the paper feed cassette 35 and the pickup roller 36 described in 1.
Registration roller pair 37, drive roller 12, intermediate transfer belt 14, registration roller pair 37 disposed diagonally above
The secondary transfer roller 39, which is arranged diagonally above the drive roller 12 and constitutes the transfer portion T with the drive roller 12, and the recording paper conveyance path 3
8, a fixing unit 40, a discharge roller pair 41, and a discharge unit 3a, which are arranged obliquely above the secondary transfer roller 39, are shown.

The paper feed section 10a is arranged at the lower part of the apparatus and the paper discharge section 3a is arranged at the upper part of the apparatus. The recording paper conveyance path 38 includes a conveyance path a between the paper feed section 10a and the registration roller pair 37, a conveyance path b between the registration roller pair 37 and the transfer section T, and a transfer section T.
The transport path c between the fixing means 40 and the fixing means 40 is provided, and these transport paths a, b, and c are sequentially arranged in one direction as indicated by an arrow z in the figure. With this configuration,
Although the recording paper P conveyed from the paper feed unit 10a to the conveyance path a is warped in the left direction in the figure, it is bent back in the conveyance paths b and c in the right direction, so that the recording paper P can be conveyed smoothly. The paper jam can be prevented. In particular, it is possible to effectively prevent paper jams of thick paper and OHP sheets.

As shown in FIGS. 5 and 6, a pair of stays 2b are provided on both sides of the lower front surface of the housing body 2, and a pair of rotating portions 3b are provided on both lower sides of the first rotating portion 3. The shaft 57 is inserted into the stay 2b and the rotating portion 3b, and the first rotating portion 3 is attached to the housing body 2 so as to be openable and closable. An operation panel 59 is arranged above the front surface of the first rotating portion 3, and an attachment / detachment opening 60 for the sheet feeding cassette 35 is formed below the first rotating portion 3. In this embodiment, each unit can be attached and detached by accessing from only the front surface of the device, and the device can be compactly installed indoors.

FIG. 6 shows a state in which the first rotating portion 3 is opened from the housing body 2. A drive motor 61 is arranged in the first rotating portion 3, and a rotating lever 63 rotatably supported by a fixed shaft 62 is arranged.
One end of the rotating lever 63 is fixed to the shaft of the secondary transfer roller 39, and the other end is fixed to the first rotating portion 3 via a spring 64.
It is moved in the direction of the arrow in the figure by the urging force of 4, and can be pressed against the intermediate transfer belt 14 and the drive roller 12. An eccentric cam 65 is provided on the spring 64 side of the rotating lever 63. The rotation lever 63 and the spring 64
The eccentric cam 65 constitutes a separating / contacting means for the secondary transfer roller.

The rotation shaft of the drive motor 61 is connected to the shaft of the fixing roller 40a via a transmission device (not shown) composed of a gear and a clutch, and a transmission device composed of a gear and a clutch (not shown). ) Through the eccentric cam 6
5 is connected to the cam shaft. With this configuration, when the drive motor 61 rotates in the normal direction, the fixing roller 40a is driven, and when the drive motor 61 rotates in the reverse direction, the eccentric cam 65 rotates,
The rotating lever 63 rotates against the spring 64 to move the secondary transfer roller 39 in the direction opposite to the arrow shown in the drawing, and separates from the intermediate transfer belt 14.

According to the present embodiment, the drive motor 61 is disposed not on the housing body 2 side but on the first rotating portion 3 side, so that the fixing means 40 and the drive motor 61 which have a heavy drive load are driven. When the opening / closing operation of the first rotating portion 3
The non-engagement configuration prevents uneven recording paper conveyance and vibration of the entire apparatus due to poor engagement of the drive system, and maintains image quality. Further, the drive motor 61 is reversely rotated at a timing when the recording paper is not conveyed, and when the secondary transfer roller 39 is separated from the intermediate transfer belt 14, the density adjustment test image and the color misregistration detection mark are displayed on the intermediate transfer belt 14. It is possible to perform a correction operation in which the secondary transfer roller 39 is formed and read by a sensor, and a separate drive source is not required for the separation / contact operation of the secondary transfer roller 39.

FIG. 7 shows a modification of the embodiment shown in FIG. In this example, when the drive motor 61 is arranged on the housing body 2 side and the first rotating portion 3 is closed to the housing body 2, the rotation shaft of the drive motor 61 is fixed to the fixing roller 40.
the eccentric cam 6 while engaging with the shaft of a.
5 is configured to be engaged with the cam shaft. In addition,
40a 'and 65' show the positions of the secondary transfer roller 40a and the eccentric cam 65, respectively, when the first rotating portion 3 is closed. For other configurations and operations, see FIG.
The description is omitted because it is the same as the embodiment.

Next, replacement of consumables will be described with reference to FIGS. 8 and 9. In FIG. 8, the housing body 2
Is provided with a shaft 66, which is a fulcrum of rotation, above the shaft 57 of the first rotating portion 3, and the shaft 66 is provided with a second frame 66.
The rotary unit 50 is rotatably mounted. The transfer belt unit 9 and the image forming unit 7 described with reference to FIG. 1 are supported by the second rotating portion 50. The image forming unit 7 and the transfer belt unit 9 are exposed when the second rotating unit 50 is rotated forward after the first rotating unit 3.

Then, as shown in FIG. 9, the developing means 20 for each color and the image carrier unit (including the frame 67a supporting the image carrier 17 and the charging means 19) 67 constituting the image forming unit 7 and the transfer. The belt unit 9 can be removed from the second rotating portion 50 and repaired or replaced. In this example, the developing means 20,
Since it is easy to secure the relative positional relationship between the image carrier 17 and the transfer belt 14, the replacement work is easy.

10 and 11 show a modification of FIG. In the present example, the transfer belt unit 9 and the image carrier unit 67 are supported by the second rotating portion 50,
The developing means 20 is supported on the housing body 2 side.
As a result, the image carrier unit 67 and the developing means 20 can be selectively and independently replaceable. The image carrier unit 67 may also be supported on the housing body 2 side.

In the present embodiment, in the space where the paper feed cassette 35 is inserted / removed at the time of replenishing the recording paper, the first rotating portion 3 as the device cover, the recording paper conveying means 37, 39, the recording paper conveying path 38, Since the fixing unit 40 is opened integrally, the maintenance workability of the fixing unit 40 and the visibility and operability in the event of a paper jam of recording paper are excellent. Further, since at least one of the transfer belt unit 9, the image carrier unit 67 and the developing means 20 can be opened to the upper space when these are integrally opened, the image carrier 17 and the developing means 20 can be exchanged, which is a consumable item. Good workability during replacement.

Further, unlike the prior art, it is not necessary to provide a large access opening for exchanging consumables in the frame supporting the image forming means, and the rigidity of the frame is improved, so that a stable and good image can be obtained. be able to.

When the second rotating portion 50 is opened,
It is possible to prevent an operator from touching the transfer belt and causing fingerprints or the like to adhere to the belt surface, resulting in image defects. Further, since the toner that has fallen during the consumable item replacement can be received by the second rotating portion 50, it is possible to prevent contamination of the recording paper conveyance means 37, 39, the recording paper conveyance path 38, and the fixing means 40.

Further, since the secondary transfer roller 39 is retracted from the transfer belt 14 by opening the first rotating portion 3, it is possible to easily remove the paper jam around the transfer belt 14 when printing a plurality of sheets. .

FIG. 12 shows the intermediate transfer belt 14, the cleaning means 15, the primary transfer member 16, and the image carrier 17 of each of the image forming stations Y, M, C and K described in FIG. A pair of left and right frames (side walls) 50a are provided on the second rotating portion 50 (FIG. 8).
The drive roller 12 and the driven roller 13 shown in FIG. 1 are attached to the paper, and the intermediate transfer belt 14 is stretched between the drive roller 12 and the driven roller 13. Drive roller 12
A belt drive gear 51 is connected to one end of each of the image carriers 17, and image carrier drive gears 52 and 52 'are connected to one end of each of the image carriers 17 between the drive gears 52 and 52'. Is engaged with the relay gear 53. Further, the drive motor 54 is disposed on the most upstream side of the belt surface 14a facing downward in the transport direction, and between the pinion gear 54a fixed to the rotating shaft of the drive motor 54 and the drive gear 52 'of the image carrier 17 on the most upstream side. A transmission gear 55 composed of a two-stage gear is meshed with the.
Reference numeral 56 denotes a toner collecting container arranged on the side surface of the frame 50a so as to collect the waste toner from the cleaning means 15.

In the above arrangement, the image carrier 17 for each color
Are commonly supported by a pair of frames (not shown), and a transmission gear 54 arranged in one row from one drive motor 54 disposed above the intermediate transfer belt 14 and an image carrier drive gear 5
2. The image carrier 17 is sequentially driven by the relay gear 53, and the drive roller 12 of the intermediate transfer belt 14 is driven by the image carrier drive gear 52 at the lowest stage via the belt drive gear 51. There is. Also, the relay gear 53
And the number of teeth of the belt drive gear 51 are the same, the rotation cycle unevenness is matched, and the interval of one rotation of the drive roller 12 and the primary transfer portion of each color image forming means are substantially the same. This allows
It is possible to match the rotational phase of each image carrier 17 and gear at the manufacturing stage, and even if the image carrier 17 is replaced, the color shift due to the uneven rotation of the image carrier 17 can be minimized. it can.

In this case, by making the conveying speed of the transfer belt 14 approximately 1 to 3% faster than the peripheral speed of the image carrier 17, it is possible to prevent the transfer belt 14 from loosening and to realize stable belt drive. In addition, it is possible to prevent color misregistration and achieve high image quality, and it is also possible to improve the transfer efficiency and eliminate the need for cleaning means by providing a speed difference.

Next, an example of the drive transmission system of the image carrier in FIG. 10 will be described with reference to FIGS. Figure 1
3 to 16 are all applied to the image forming apparatus in which the developing unit 20 is supported on the housing body 2 side and the image carrier unit 67 and the transfer belt unit 9 are supported on the second rotating portion 50 in FIG. To be done.

In FIG. 13, the drive motor 54 and the transmission gear 55 described in FIG. 12 are mounted on the housing body 2 side, and the belt drive gear 51 and the image carrier drive gear 5 are attached.
2 ′, 52 and the relay gear 53 are the image carrier unit 67.
It is installed on the side. The shafts of the transmission gear 55, the image carrier driving gears 52 'and 52, and the relay gear 53 are the belt surface 14a.
It has a 1-row wheel train parallel to, which minimizes the number of gears and constitutes a simple drive system. Then, as shown in FIG. 9A, the transfer belt unit 9 is rotated in the direction of arrow P about the shaft 66, and as shown in FIG. 9B, the most upstream side of the belt surface 14a facing downward in the transport direction. The image carrier driving gear 52 'is engaged with the transmission gear 55 to be mounted. At this time, by rotating all the image carrier driving gears 52 ', 52, they are mounted and positioned on the main body,
The transmission gear 55 and the image carrier driving gear 52 'mesh with each other in the rotational normal direction R when mounted.

According to the above construction, the transmission gear 55 is mounted when mounted.
And the image carrier drive gear 52 'mesh with each other while rotating slightly, resulting in smooth meshing and damage to the gear,
It is possible to prevent the tooth tips from colliding and being unable to engage with each other. Further, although the rotation and attachment / detachment operation of the image carrier 17 is frequently performed, even if there is an attachment / detachment error in the rotation direction at that time, the meshing between the transmission gear 55 and the image carrier drive gear 52 'does not change, so that it is stable. The driving force can be transmitted.

In the example of FIG. 14, all the image carrier driving gears 52 ', 52 are mounted and positioned on the main body by rotating operation, and the transmission gear 55 and the image carrier driving in the rotational tangential direction Q at the time of mounting. The gear 52 'is in mesh with each other. According to this example, even if the relative positions of the transmission gear 55 and the image carrier drive gear 52 'change due to the difference in the linear expansion coefficient between the main body frame and the image carrier frame, the transmission gear 55
Since the meshing between the image carrier driving gear 52 'and the image carrier driving gear 52' does not change, stable driving force can be transmitted.

In the example of FIG. 15, the driving roller 12 of the transfer belt 14 is arranged at the upper part, the driven roller 13 is arranged at the lower part, the transmission gear 55 is meshed with the belt driving gear 51, and the belt driving gear 51 carries the image. Body drive gear 5
I'm trying to mesh with 2 '. According to the present example, the driving force from the driving motor 54 is first of all the belt driving gear 51.
To the image carrier drive gear 52 ′ on the most upstream side, and in order to the image carrier drive gear 52 below.

According to the present example, by driving the transfer belt 14 on the upstream side of the driving force transmission path, the transfer belt 14 is less affected by the speed fluctuation generated on the transmission path than it is driven on the downstream side. Color deviation and image pitch unevenness (banding) that occur at the primary transfer part by suppressing the speed fluctuation of 14
Can be prevented. Further, the driving force from the transmission gear 55 is the same as the mounting direction of the image carrier 17, and it is possible to prevent the position of the image carrier 17 from changing due to the driving force.

In this case, by slowing the conveying speed of the transfer belt 14 by about 1 to 3% lower than the peripheral speed of the image carrier 17, it is possible to prevent the transfer belt 14 from loosening and to realize stable belt drive. In addition, it is possible to prevent color misregistration and achieve high image quality, and it is also possible to improve the transfer efficiency and eliminate the need for cleaning means by providing a speed difference.

In the example of FIG. 16, the drive roller 12 and the drive motor 54 of the transfer belt 14 are arranged in the lower part, the driven roller 13 is arranged in the upper part, and the transmission gear 55 is arranged.
The belt drive gear 51,
Is engaged with the image carrier drive gear 52.
According to this example, the driving force from the driving motor 54 is
It is transmitted to the belt drive gear 51, then to the most downstream image carrier drive gear 52, and in turn to the upper image carrier drive gear 52.

According to this example, by driving the transfer belt 14 on the upstream side of the driving force transmission path, it is less affected by the speed fluctuation generated on the transmission path than it is on the downstream side. Color deviation and image pitch unevenness (banding) that occur at the primary transfer part by suppressing the speed fluctuation of 14
Can be prevented.

In this case, slack of the transfer belt 14 can be prevented and stable belt drive can be realized by making the conveying speed of the transfer belt 14 slower than the peripheral speed of the image carrier 17 by about 1 to 3%. In addition, it is possible to prevent color misregistration and achieve high image quality, and it is also possible to improve the transfer efficiency and eliminate the need for cleaning means by providing a speed difference.

Further, as shown in FIG. 6B, the meshing position with the image carrier driving gear 52 that rotates together with the image carrier when the image carrier is mounted is the rotation center position 66 when the image carrier is mounted. Therefore, even if there is a positioning error of the image carrier, the influence at the meshing position is small and the meshing between the transmission gear 55 and the image carrier driving gear 52 does not change.
A stable driving force can be transmitted.

As described above, in the present embodiment, since the intermediate transfer belt 14 is arranged in the direction inclined with respect to the driving roller 12, a wide space is generated in the right space in the drawing and the fixing is performed in that space. The means 40 can be provided, and downsizing can be realized, and the heat generated by the fixing means 40 causes the exposure unit 6, the intermediate transfer belt 14 and the image forming stations Y, M, which are located on the left side. It is possible to prevent transmission to C and K. Further, since the exposure unit 6 can be arranged in the space on the lower left side of the image forming unit 7, the vibration of the scanning optical system of the exposure unit 6 caused by the vibration given to the housing body 2 by the drive system of the image forming means is minimized. It is possible to prevent the deterioration of the image quality.

Further, in the present embodiment, the primary transfer efficiency is increased (approximately 100%) by using the spherical toner, and the cleaning for recovering the residual toner after the primary transfer is performed on each image carrier 17. No means are set up. As a result, it is possible to arrange the image bearing members 17 each including a photosensitive drum having a diameter of 30 mm or less in close proximity to each other, and the device can be downsized.

Since the cleaning means is not installed, the corona charging means 19 is used as the charging means. When the charging means is a roller, a small amount of the primary transfer residual toner existing on the image carrier 17 is accumulated on the roller to cause charging failure, but the corona charging means 19 which is a non-contact charging means. The toner is less likely to adhere to the toner, and the occurrence of poor charging can be prevented.

The outline of the operation of the entire image forming apparatus as described above is as follows. (1) When a print command signal (image forming signal) from a host computer or the like (not shown) (personal computer or the like) is input to the control unit 4 of the image forming apparatus 1, each of the image forming stations Y, M, C, and K. The image carrier 17, each roller of the developing device 20, and the intermediate transfer belt 14 are rotationally driven. (2) The outer peripheral surface of the image carrier 17 is uniformly charged by the charging means 19. (3) The exposure unit 6 selectively exposes the outer peripheral surface of the image carrier 17 uniformly charged in each of the image forming stations Y, M, C, and K in accordance with the image information of each color. An electrostatic latent image is formed. (4) The toner images of the electrostatic latent images formed on the respective image carriers 17 are developed by the developing means 20. (5) A primary transfer voltage having a polarity opposite to the charging polarity of toner is applied to the primary transfer member 16 of the intermediate transfer belt 14, and the toner image formed on the image carrier 17 is transferred to the intermediate transfer belt at the primary transfer portion. Along with the movement of 14, the images are sequentially transferred and superposed on the intermediate transfer belt 14. (7) Intermediate transfer belt 14 to which this primary image is primarily transferred
The recording medium P stored in the paper feeding cassette 35 is fed to the secondary transfer roller 39 via the pair of registration rollers 37 in synchronization with the movement of the sheet. (8) The primary transfer image is synchronously merged with the recording medium at the secondary transfer portion, and the primary transfer image is generated by the secondary transfer roller 39 pressed toward the drive roller 12 of the intermediate transfer belt 14 by a pressing mechanism (not shown). A bias having a polarity opposite to that of the transfer image is applied, and the primary transfer image formed on the intermediate transfer belt 14 is secondarily transferred to the recording medium that is synchronously fed. (9) The untransferred toner in the secondary transfer is conveyed toward the driven roller 13 and is scraped off by the cleaning means 15 arranged facing the roller 13, and the intermediate transfer belt 14 is refreshed. Then, the above cycle can be repeated again. (10) The toner image on the recording medium is fixed by passing the recording medium through the fixing means 40, and then the recording medium is directed to a predetermined position (when it is not double-sided printing, it is directed to the discharge tray 3a and double-sided printing). In the case of (2), it is conveyed toward the double-sided printing conveyance path 42).

FIG. 17 is a schematic sectional view showing the overall construction of another embodiment of the image forming apparatus of the present invention. The same components as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The present embodiment is an example of the above-described paper conveyance system, and uses the paper conveyance belt 43 instead of the intermediate transfer belt 14 in FIG.

In this embodiment, the transfer unit 9 and the paper conveying means 11 are provided in the first rotating portion 3.
The transfer unit 9 is disposed above the housing main body 2 and is driven by a drive source (not shown) to rotate, and a driven roller 13 and a backup roller 44 disposed obliquely below the drive roller 12. A paper conveyance belt 43 stretched around three rollers and circulated in the direction of the arrow (clockwise) shown in the figure, and a backup roller 44.
And a cleaning unit 15 that abuts against the surface of the paper transport belt 43, and the drive roller 12 and the paper transport belt 43 are arranged in a direction inclined to the left side in the figure with respect to the driven roller 13. As a result, the belt tension side (the side pulled by the drive roller 12) 43a when the paper transport belt 43 is driven is positioned below, and the belt slack side 43b is positioned above.

Further, a transfer member 45 composed of a leaf spring electrode is brought into contact with the back surface of the paper transport belt 43 by its elastic force so as to face the image carrier 17 of each image forming station Y, M, C, K. A transfer bias is applied to the transfer member 45. Then, the image forming stations Y, M, C, K
The image bearing member 17 of the paper conveyance belt 43 is on the belt tension side 43 of the paper conveyance belt 43.
As a result, the image forming stations Y, M, C, and K are also arranged in a direction inclined to the left side with respect to the driven roller 13 in the drawing.

FIG. 18 is a schematic sectional view showing the overall construction of another embodiment of the image forming apparatus of the present invention. The same components as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The present embodiment is an example in which the intermediate transfer belt 14 and the image forming stations Y, M, C, and K are arranged in the vertical direction. Other configurations and operational effects are similar to those of the embodiment shown in FIG. 1, and therefore description thereof will be omitted.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and a conventionally known or well-known technique can be replaced or added as necessary.

For example, in the embodiment shown in FIGS. 1 and 18, the driving roller 12 is arranged below the driven roller 13 but the driven roller 13 is arranged below and the driving roller 13 is arranged above. May be.

Further, in the above embodiment, the rotation fulcrum 66 of the first rotation portion 3 and the second rotation portion 50 is provided in the lower portion of the housing body 2 so as to be vertically rotatable. A rotation fulcrum may be provided on the side of the housing body 2 so as to be rotatable in the horizontal direction.

In the present invention, the intermediate transfer belt and the paper carrying belt are generically defined as a transfer belt.

[0076]

As is apparent from the above description, according to the present invention, it is possible to easily replace consumables in an image forming apparatus in which image forming stations are arranged diagonally or vertically. It is possible to easily perform maintenance of the fixing device itself and clear paper jam around the transfer belt and around the fixing device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an overall configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the transfer belt and the image forming unit of FIG.

FIG. 3 is an enlarged view of the exposure unit of FIG.

FIG. 4 is an enlarged view of the paper conveying unit in FIG.

FIG. 5 is a front view seen from the right in FIG.

FIG. 6 is a schematic cross-sectional view showing a state in which a first rotating portion is opened in FIG.

FIG. 7 is a diagram for explaining a modified example of the embodiment of FIG.

FIG. 8 is a schematic cross-sectional view showing a state where the second rotating portion is opened following FIG.

FIG. 9 is a diagram for explaining replacement of consumables in FIG.

FIG. 10 is a diagram for explaining a modified example of the embodiment of FIG.

FIG. 11 is a diagram for explaining replacement of consumables in FIG.

FIG. 12 is a perspective view of the transfer belt and the image carrier of FIG.

13 is a diagram for explaining an example of a drive transmission system of the image carrier in FIG.

14 is a diagram for explaining an example of a drive transmission system of the image carrier of FIG.

15 is a diagram for explaining an example of a drive transmission system of the image carrier of FIG.

16 is a diagram for explaining an example of a drive transmission system of the image carrier of FIG.

FIG. 17 is a schematic cross-sectional view showing another embodiment of the image forming apparatus of the invention and showing the overall configuration.

FIG. 18 is a schematic cross-sectional view showing another embodiment of the image forming apparatus of the invention and showing the overall configuration.

[Explanation of symbols]

Y, M, C, K ... Image forming station 2… Housing body 3 ... 1st rotation part 12 ... Drive roller 13 ... driven roller 14 ... Intermediate transfer belt (transfer belt) 17 ... Image bearing member 19 ... Charging means 20 ... Developing means 39 ... Secondary transfer roller 40 ... Fixing means 43 ... Paper transport belt (transfer belt) 50 ... Second rotating portion 51 ... Belt drive gear 52 ... Image carrier drive gear 53 ... Relay gear 54 ... Drive motor 55 ... Transmission gear 61 ... Drive motor 66 ... Rotation fulcrum

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 103 G03G 15/00 554 (72) Inventor Yujiro Nomura 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson In-house F-term (reference) 2H030 AA06 AB02 AD04 AD05 BB02 BB23 BB42 BB44 BB46 2H071 AA04 AA15 AA18 AA19 AA20 BA03 BA04 BA13 BA14 BA15 BA20 CA02 CA05 DA06 DA08 DA09 DA23 DA26 EA04 EA06 EA18 2H200 GA23 GA34 FA20 FA12 FA20 FA12 FA20 GB43 GB44 HA02 HA12 HA28 HB03 HB12 HB23 JA02 JA21 JB07 JB10 JB20 JB26 JB39 JC04 JC09 JC12

Claims (14)

[Claims] 1. An image forming station, in which a charging unit and a developing unit are arranged around an image carrier, is provided for each color along a transfer belt, and the transfer belt and each image forming station are arranged obliquely or vertically. In the image forming apparatus described above, a housing body in which each of the image forming stations and the transfer belt are disposed, and a first rotating portion and a second rotating portion rotatably mounted on the housing body. And a paper conveying unit and a fixing unit arranged on the first rotating unit, and at least one of a developing unit, an image carrier and a transfer belt arranged on the second rotating unit. Image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the rotation fulcrums of the first rotation portion and the second rotation portion are provided in a lower portion of the housing body. 3. The image forming apparatus according to claim 1, wherein the rotation fulcrums of the first rotation portion and the second rotation portion are provided beside the housing body. 4. The image forming apparatus according to claim 1, wherein the transfer belt is a paper transport belt. 5. The image forming apparatus according to claim 1, wherein the transfer belt is an intermediate transfer belt. 6. The image forming stations are arranged in an oblique direction, and the image carrier of each image forming station is arranged so as to abut on a belt surface of the intermediate transfer belt facing downward in the conveying direction. The image forming apparatus according to claim 5. 7. The driven roller of the intermediate transfer belt is disposed obliquely above the drive roller, and the drive roller and the secondary transfer roller form a secondary transfer portion. Image forming apparatus. 8. The image forming apparatus according to claim 6, wherein a fixing unit is disposed obliquely above a belt surface of the intermediate transfer belt which is upward in the conveying direction. 9. The image forming apparatus according to claim 6, wherein the first rotating portion is provided with a separating / contacting means of a secondary transfer roller which separates / contacts the intermediate transfer belt. 10. The image forming apparatus according to claim 6,
Rotational fulcrums of the first rotating portion and the second rotating portion are provided in the lower portion of the housing body, and the driven roller of the intermediate transfer belt is disposed obliquely above the drive roller, and the second roller is provided. An image carrier and a transfer belt of each color arranged on the rotating portion, a belt drive gear that drives the drive roller, and an image carrier drive gear that meshes with the belt drive gear and drives the image carrier of each color. , A relay gear meshed between the image carrier driving gears of the respective colors, a drive motor provided on the housing main body side on the most upstream side of the belt surface facing downward in the transport direction, and the drive motor and the most upstream side An image forming apparatus, comprising: a transmission gear meshed with an image carrier driving gear. 11. The transmission gear and the most upstream side image carrier driving gear mesh with each other in a rotation normal direction when the second rotating portion is rotated and mounted. The image forming apparatus described. 12. The transmission gear and the most upstream side image carrier driving gear mesh with each other in a rotational tangential direction when the second rotating portion is rotated and mounted. Image forming device. 13. The image forming apparatus according to claim 6,
Rotational fulcrums of the first rotating portion and the second rotating portion are provided in the lower portion of the housing body, and the driving roller of the intermediate transfer belt is disposed obliquely above the driven roller, and the second rotating portion is provided. An image carrier and a transfer belt of each color arranged on the rotating portion, a belt drive gear that drives the drive roller, and an image carrier drive gear that meshes with the belt drive gear and drives the image carrier of each color. , A relay gear meshed between the image carrier driving gears of the respective colors, a drive motor provided on the housing main body side, disposed on the most upstream side of the belt surface facing downward in the conveying direction, and the drive motor and the belt drive gear. An image forming apparatus comprising: a transmission gear meshed with each other. 14. The image forming apparatus according to claim 6,
Rotational fulcrums of the first rotating portion and the second rotating portion are provided in the lower portion of the housing body, and the driven roller of the intermediate transfer belt is disposed obliquely above the drive roller, and the second roller is provided. An image carrier and a transfer belt of each color arranged on the rotating portion, a belt drive gear that drives the drive roller, and an image carrier drive gear that meshes with the belt drive gear and drives the image carrier of each color. , A relay gear meshed between the image carrier driving gears of the respective colors, a drive motor provided on the housing body side and disposed on the most downstream side of the belt surface facing downward in the transport direction, and the drive motor and the belt drive gear. An image forming apparatus comprising: a transmission gear meshed with each other.