JP3061753B2 - Color electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color electrophotographic apparatus applicable to a color copying machine, a color facsimile, and the like.

[0002]

2. Description of the Related Art As an example of a conventional color electrophotographic apparatus,
The configuration will be described with reference to JP-A-7-36246. FIG. 7 is an overall configuration diagram of the conventional color electrophotographic apparatus. The intermediate transfer belt unit 101 includes a transfer belt 102, a first transfer roller 103, and a second transfer roller 10.
4. A cleaner roller 105, a waste toner reservoir 106, and the like are included, and a color image is superimposed on the belt 102.
In the center of the printer, four fan-shaped image forming units 107 of the same size for each color of black, cyan, magenta, and yellow.
Bk, 107Y, 107M, and 107C constitute the image forming unit group 108, and are arranged in an annular shape as shown in the figure.

When the image forming unit 107 is properly mounted in the printer, the mechanical drive system and the electric circuit system on both the image forming unit side and the printer side are connected via a mutual coupling member, and the And electrical integration. Image forming unit 107B arranged in an annular shape
k, 107Y, 107M, and 107C are supported by a support, are driven by a moving motor as a whole, and are configured to be rotatable about a fixed, non-rotating cylindrical shaft 109. At the time of image formation, each image forming unit can be sequentially positioned at an image forming position 110 facing the first transfer roller 103 that supports the intermediate transfer belt 102 by rotational movement. The image forming position 110 is the laser light 1
11 is also the exposure position.

Reference numeral 112 denotes a laser exposure device disposed on the lower side of the printer. The laser signal light 111 is supplied to an optical path window 11 formed between the image forming units 107M and 107C.
3, the light enters a fixed mirror 114 in the shaft 109 through a window opened in a part of the shaft 109, is reflected and is reflected from the exposure window 115 of the image forming unit 107Bk at the image forming position 110 to the image forming unit. 107Bk, and the developing device 1 disposed vertically in the image forming unit
The light passes through an optical path between the photoconductor 16 and the cleaner 117 and is incident on an exposure portion on the left side surface of the photosensitive drum 118, and is scanned and exposed in the generatrix direction.

The toner image formed on the photoreceptor 118 is transferred to the transfer belt 102, and then the image forming unit group 10
8 rotates 90 degrees, and the yellow image forming unit 107
Y is replaced with the image forming position 110. The same operation as in the previous black step is performed, and the yellow toner image is superimposed on the black toner image on the intermediate transfer belt 102. The same operation is further performed using magenta and cyan image forming units, and after a full-color image is completed on the intermediate transfer belt 102, the third operation is performed.
The color image is transferred to the paper by the transfer roller 119, and is fixed by the fixing device 120. This is the configuration of JP-A-7-36246.

[0006]

With the recent spread of personal computers and the like, this color electrophotographic apparatus is required to be able to be used on a desktop without taking up space.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color electrophotographic apparatus which is easy to maintain and has little positional deviation for each color.

[0008]

According to the present invention, there is provided an image forming unit for forming a toner image on a photoconductor, and a color image formed by transferring the toner image formed on the photoconductor. An intermediate transfer belt to be formed, a backup roller for supporting the intermediate transfer belt unit, an intermediate transfer belt unit housed in a housing portion provided in the apparatus, and an intermediate transfer belt provided so as to be able to contact and separate from the intermediate transfer belt. A retransfer roller that transfers a color image from the intermediate transfer belt to recording paper by contacting a transfer belt unit at a position facing the backup roller after transferring a color image from the photoconductor to an intermediate transfer belt;
A belt provided on the intermediate transfer belt and having unit guide means for an intermediate transfer belt unit to be mounted on the apparatus; and a device guide means provided on the apparatus and guiding the intermediate transfer belt unit to the predetermined position. Unit guide means, and when the intermediate transfer belt unit is stored in the storage portion, the retransfer roller is located at a separated position different from the retransfer position, and the intermediate transfer belt unit is When the image is re-transferred from the intermediate transfer belt unit accommodated in the accommodating portion to the recording paper by being guided by the guide means of the apparatus and guided by the photosensitive member in a direction perpendicular to the rotation axis of the photosensitive member, The re-transfer roller moves upward from below, and the pressing force on the intermediate transfer belt is substantially directly in the guide direction of the intermediate transfer belt unit. A color electrophotographic apparatus characterized by being configured to abut on an intermediate transfer belt so as to form a corner.

Further, the present invention provides an intermediate transfer belt on which a toner image formed on a photoreceptor is transferred to form a color image, a backup roller for supporting the intermediate transfer belt unit, and a guide for mounting to an apparatus. Means for guiding a color image to a recording sheet, wherein a guide direction of the apparatus main body to a housing portion by a guide means of the apparatus main body is perpendicular to a rotation axis of the photoconductor. The intermediate transfer belt unit is characterized in that the re-transfer roller that can be contacted and separated is set to be substantially perpendicular to the direction of the pressing force when it comes into contact with the intermediate transfer belt.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color electrophotographic apparatus according to a first aspect of the present invention includes an image forming unit for forming a toner image on a photoreceptor, and a color image on which the toner image formed on the photoreceptor is transferred. An intermediate transfer belt, and a backup roller that supports the intermediate transfer belt unit. The intermediate transfer belt unit is housed in a housing unit provided in the apparatus. And a retransfer roller for transferring a color image from the intermediate transfer belt to recording paper by contacting a transfer belt unit at a position facing the backup roller after transferring a color image from the photoconductor to an intermediate transfer belt. ,
A belt provided on the intermediate transfer belt and having unit guide means for an intermediate transfer belt unit to be mounted on the apparatus; and a device guide means provided on the apparatus and guiding the intermediate transfer belt unit to the predetermined position. Unit guide means, and when the intermediate transfer belt unit is stored in the storage portion, the retransfer roller is located at a separated position different from the retransfer position, and the intermediate transfer belt unit is When the image is re-transferred from the intermediate transfer belt unit accommodated in the accommodating portion to the recording paper by being guided by the guide means of the apparatus and guided by the photosensitive member in a direction perpendicular to the rotation axis of the photosensitive member, The re-transfer roller moves upward from below, and the pressing force on the intermediate transfer belt is substantially directly in the guide direction of the intermediate transfer belt unit. The intermediate transfer belt is configured to be in contact with the intermediate transfer belt so as to form a corner.

According to a second aspect of the present invention, there is provided a color electrophotographic apparatus according to the first aspect, wherein the belt unit guide means comprises a guide groove and a guide pin,
The guide pin is configured to be guided by the guide groove only in a direction perpendicular to the photoconductor rotation axis with respect to the photoconductor.

In a color electrophotographic apparatus according to a third aspect of the present invention, in the first aspect of the present invention, the apparatus main body includes an image forming unit group rotatably supporting the image forming unit, and a color image transferred thereto. An intermediate transfer belt unit, a fixing device for fixing a color image on recording paper re-transferred from the intermediate transfer belt, and an intermediate transfer belt unit, an image forming unit group, and a fixing device below each of the fixing device. A paper feed unit provided at a lower portion, a feed roller for feeding the recording paper in the paper feed unit, and a paper transport path for transporting the recording paper, the paper feed path being provided in the apparatus main body and being fed from the feed roller A sheet guide provided on a front plate that is openable and closable in the apparatus main body, and a sheet conveying path having a conveying path continuous with the paper guide, and an intermediate transfer belt unit is provided in the apparatus main body. When mounted, the front plate is opened and the conveyance path is released from a predetermined position so that the intermediate transfer belt unit is guided by the guide means of the apparatus, while the paper feeding unit, the feeding roller, and the paper The guide was configured to remain at a predetermined position.

A color electrophotographic apparatus according to a fourth aspect of the present invention is the image forming unit according to any one of the first and third aspects of the present invention, wherein the apparatus main body comprises an image forming unit rotatably supporting the image forming unit. A group, a laser exposure device that exposes the photoconductor, an intermediate transfer belt unit onto which a color image is transferred, a fixing device that fixes a color image on recording paper retransferred from the intermediate transfer belt, an intermediate transfer belt unit, A sheet feeding unit provided below the image forming unit group and the fixing device and provided at a lower portion of the apparatus main body, and an intermediate transfer belt unit and an image forming unit group provided above each, A paper transport path for transporting recording paper from the paper feeding unit to the paper discharging unit, wherein the paper feeding unit and the paper discharging unit include an intermediate transfer belt unit and Provided to the corresponding across fine the image forming unit group, the paper feed unit, the paper transport path and the space formed by the discharge unit,
The intermediate transfer belt unit, the image forming unit group, and the laser exposure device are arranged.

According to a fifth aspect of the present invention, there is provided a color electrophotographic apparatus according to the fourth aspect, wherein the color electrophotographic apparatus is opened and closed with respect to the apparatus main body on a side different from the image forming unit group with the intermediate transfer belt unit interposed therebetween. A front plate that is provided so as to allow a space for accommodating the intermediate transfer belt unit to be surrounded by the paper feed unit, the paper discharge unit, and the image forming unit group, by opening the front plate. The intermediate transfer belt unit is configured to be detachably accommodated in an accommodation space of the intermediate transfer belt unit that appears when the front plate is opened.

An intermediate transfer belt unit according to a sixth aspect of the present invention includes an intermediate transfer belt on which a toner image formed on a photosensitive member is transferred to form a color image, and a backup roller for supporting the intermediate transfer belt unit. And a guide means for mounting the apparatus on the apparatus. A guide direction of the guide means of the apparatus body to a housing portion of the apparatus body is a direction perpendicular to a rotation axis of the photoconductor, and a recording sheet. And a re-transfer roller which can be separated from and separated to transfer a color image to the intermediate transfer belt is set so as to be substantially perpendicular to the direction of the pressing force when contacting the intermediate transfer belt.

The present invention may have the following configuration.

According to another aspect of the present invention, there is provided a color electrophotographic apparatus, comprising: a plurality of image forming units each including a developing unit, a charging unit, and a photosensitive member for each color; An image forming unit group which can be held and rotatably moved to an image forming position and other positions while being arranged and arranged in an annular shape, a laser exposure device arranged outside the image forming unit group, and an image forming unit A center mirror disposed at a substantially central portion of the group, an intermediate transfer belt unit including an intermediate transfer belt for receiving a toner image formed on a photoconductor at an image forming position and forming a color image therein, Retransfer means for transferring the color image formed on the intermediate transfer belt to recording paper at a retransfer position, and at least three of the laser exposure devices are provided with an image forming unit group and an intermediate transfer belt. Configure and disposed in a space surrounded by the sheet transport path for transporting the winding unit and the recording sheet from the feeding position to the re-transfer means.

A color electrophotographic apparatus according to another aspect of the present invention includes a paper feed unit for storing recording paper, and includes a laser exposure device that includes a group of image forming units, an intermediate transfer belt unit, a paper transport path, the paper feed unit, It is arranged in the space surrounded by.

In a color electrophotographic apparatus according to another aspect of the present invention, at the time of image recording, a laser beam is reflected by a center mirror and acts on a photosensitive member at an image forming position across a path leading to an image forming position. The laser beam is incident on the center mirror from the side opposite to the developing device.

In a color electrophotographic apparatus according to another aspect of the present invention, the laser exposure apparatus comprises a polygon mirror,
The rotation surface of the polygon mirror is inclined with respect to a horizontal plane, and the inclination angle is 60 degrees or less.

A color electrophotographic apparatus according to another aspect of the present invention includes a belt cleaning means for removing toner remaining on the intermediate transfer belt inside the intermediate transfer belt unit, and a laser light emission window of the laser exposure device is provided in the printer body. And a vertical line from the cleaning position of the intermediate transfer belt by the belt cleaning unit with respect to the outermost envelope of the image forming unit group in the side view of FIG.

In a color electrophotographic apparatus according to another aspect of the present invention, an intermediate transfer belt unit is configured to be detachable from a printer main body, and a retransfer unit is a retransfer roller provided on the printer main body. A belt unit guide unit for guiding the intermediate transfer belt unit to a predetermined storage position; and a backup roller for contacting the retransfer roller with the intermediate transfer belt unit, wherein the belt unit at the predetermined storage position is provided. The guide direction of the intermediate transfer belt unit by the guide unit is substantially perpendicular to the direction of the pressing force when the retransfer roller comes into contact with the backup roller.

In a color electrophotographic apparatus according to another aspect of the present invention, the intermediate transfer belt unit has a sectional shape narrowing toward the center mirror.

A color electrophotographic apparatus according to another aspect of the present invention includes an intermediate mirror that folds a laser beam toward a center mirror, and irradiates the photosensitive member at an image forming position with the intermediate mirror and the center mirror. Is folded back so as to have a substantially Z-shape.

A color electrophotographic apparatus according to another aspect of the present invention is configured such that the incident angle of the laser beam to the intermediate mirror and the center mirror is 30 degrees or less.

In a color electrophotographic apparatus according to another aspect of the present invention, an intermediate transfer belt unit is configured to be detachable from a printer main body, an openable front plate, and an opening that opens when the front plate is opened. And a belt unit guide unit that engages with the intermediate transfer belt unit and guides the intermediate transfer belt unit to a predetermined storage position. The guide direction of the intermediate transfer belt unit by the belt unit guide unit is a center. It is configured so as to be in a range from the horizontal direction around the mirror to the upper end of the opening.

According to another aspect of the present invention, there is provided a color electrophotographic apparatus for forming an image, wherein the image forming unit engages with the image forming unit and guides the image forming unit to a predetermined position of the image forming unit group. The image forming unit includes a unit guide, and a guide direction of the image forming unit by the image forming unit guide is in a range of 30 degrees or more and 90 degrees or less with respect to the guide direction of the intermediate transfer belt unit.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

Embodiment 1 The structure of a color electrophotographic apparatus according to the present invention will be described with reference to FIGS. Reference numeral 1 denotes a printer main body of the color electrophotographic apparatus, and the right end side of the drawing is the front of the apparatus. Reference numeral 1A denotes a printer front plate. The front plate 1A can be freely opened and closed and raised and closed with respect to a printer outer casing 1D about a lower hinge shaft 1B. FIG. 2 shows a state where the front plate 1A is folded down and opened. Maintenance inside the printer, such as when a paper jam occurs, is performed by opening the front plate 1A to open the printer greatly. FIG. 3 shows the intermediate transfer belt unit 2. Intermediate transfer belt unit 2
From the unit case 3, the transfer belt 4, the transfer guide roller 9, the re-transfer backup roller 6, the drive roller 8, the tension roller 5, the waste toner reservoir 10, the waste toner full detector 11, the position detector 12, and the cleaner unit 15. Become.

The intermediate transfer belt unit 2 is provided with a center mirror 4 by two surfaces 3A and 3B of the unit case 3.
It has a cross-sectional shape narrowing toward 9. The driving roller 8 is disposed above the transfer guide roller 9, the re-transfer backup roller 6, and the tension roller 5, and obtains a driving force by a driving unit (not shown) of the printer main body 1.
The intermediate transfer belt 4 is configured to be driven in the direction of arrow Y. Further, the drive roller 8 is disposed so as to protrude forward (to the right in the drawing) from the retransfer backup roller 6 so as to form an overhang portion 4A on the intermediate transfer belt 4 from the retransfer backup roller 6 toward the drive roller 8. I have. The cleaner unit 15 includes a cleaning blade 7, a toner receiver 17, and a cam follower 16, and is mounted to be swingable around a swing shaft 18.

The cleaner unit 15 is arranged such that the cleaning blade 7 is brought into contact with the drive roller 8 via the intermediate transfer belt 4 by means such as a spring (not shown).
It is configured to receive an urging force. Printer body 1
The intermediate transfer belt unit 2 is provided with a cam follower 16 when the intermediate transfer belt unit 2 is mounted on the printer body 1.
And is configured to engage with. Cleaner unit 1
5 and the waste toner reservoir 10 are communicated through a communication port 19, and the waste toner scraped off by the cleaning blade 7 by a known means such as a screw shaft is disposed on the inner peripheral side of the intermediate transfer belt 4. It is configured to be transported to the reservoir 10.

The intermediate transfer belt 4 is made of an endless belt-like semiconductive (medium resistance) urethane having a thickness of 100 μm, and the surface layer is made of a fluororesin such as PFA / PTFE and has a total thickness of 100 to 500 μm. It consists of a film.

In order to perform A4 size or letter size full-color printing, the intermediate transfer belt 4 is set so that the peripheral length of the transfer belt is set to the maximum length of the A4 image receiving paper (297 mm) in the longitudinal direction (297 mm). Length (80m) that is slightly longer than half the circumference of the body drum (diameter 30mm)
m) plus 377 mm. At this time, the peripheral length of the intermediate transfer belt 4 from the retransfer position of the retransfer backup roller 6 to the contact portion of the drive roller 8 with the cleaning blade 7 is shorter than the distance of 80 mm, and is 75 m.
m.

The moving speed of the intermediate transfer belt 4 is 1.5 times lower than the image forming speed of the image forming unit (100 mm / s, which is equal to the peripheral speed of the photosensitive member) in order to prevent the transfer of the toner image.
% Faster.

When transferring the toner image on the photosensitive member, a voltage of about +2.5 kV (100 μA) is applied to the transfer guide roller 9 and the tension roller 5 by a high-voltage power supply (not shown). At this time, if the transfer guide roller 9 is brought into contact with the photosensitive member to transfer the toner image to the intermediate transfer belt 4, a so-called "front jump" phenomenon occurs before the intermediate transfer belt 4 contacts the photosensitive member, and the image is disturbed. In addition, it becomes difficult to uniformly adjust the contact pressure between the transfer guide roller 9 and the photosensitive member. However, such a problem does not occur in the configuration in which the intermediate transfer belt 4 stretched between the transfer guide roller 9 and the tension roller 5 is brought into contact with the photosensitive drum as in the present embodiment.

The diameter of the driving roller 8 and the retransfer backup roller 6 is 30 mm. The diameter of the tension roller 5 and the transfer guide roller 9 is 15 mm. The peripheral length of the intermediate transfer belt 4 is configured to be an integral multiple of the outer peripheral length of each roller, thereby preventing color shift of each color. Reference numeral 20 shown in FIG. 4 is a detection hole for detecting the position of the belt. The position detector 12 is configured to optically detect the passage of the detection holes 20 to determine the position of the leading end of the toner image, and to position the color image on the intermediate transfer belt 4.

Here, the transmission type position detecting means is used as the position detecting means, but it goes without saying that a mechanical type, an electric type, a magnetic type or the like other than the optical type may be used.

On both sides of the intermediate transfer belt unit 2,
As shown in FIG. 2, rib-shaped guide grooves 61 and 62 are provided as guide means for mounting on the printer main body 1. Guide pins 63 and 64, which are guide means, are provided on the printer body 1 side.
The intermediate transfer belt unit 2 guides the intermediate transfer belt unit 2 in the direction of arrow R by engaging with 62. Reference numeral 71 denotes an opening that is opened when the front plate 1A is folded down and opened. The opening 71 also serves as an insertion opening for the intermediate transfer belt unit 2. 65 is a horizontal line drawn from the center mirror 49, 66 is the center mirror 4
9 is a line connecting 9 to the upper end 57 of the opening 71. The intermediate transfer belt unit 2 is configured to be inserted into the printer main body 1 from between the horizontal line 65 and the line 66.

In the center of the left side of the printer, yellow, magenta,
Four substantially fan-shaped image forming units 21Y, 21M, 21C, and 21Bk for the respective colors of cyan and black form an image forming unit group 22, and are arranged in an annular shape as shown in the figure.
Each image forming unit is detachable at a predetermined position of the image forming unit group 22 by opening the printer upper plate 1C of FIG. 2 and opening the insertion port 72 of the image forming unit 21.

When the image forming unit 21 is properly mounted in the printer, the mechanical drive system and the electric circuit system on both the image forming unit side and the printer side are connected via a mutual coupling member (not shown). To combine mechanically and electrically. As shown in FIG. 2, guide pins 67 and 68 are provided on both sides of the image forming unit 21 as guide means for mounting the image forming unit 21 on the printer main body 1. A support (not shown) for supporting the image forming unit 21 is provided on the printer body 1 side, and the support is provided with guide grooves 69 and 70 as guide means. The guide pins 67 and 68 engage with the guide grooves 69 and 70 to guide the image forming unit 21 in the direction of arrow T.

Image forming unit 2 arranged in an annular shape
1Y, 21M, 21C and 21Bk are supported by a support, and are driven by a moving motor 23 as a moving means as a whole of the image forming unit group 22, and are rotatable around a fixed and non-rotating cylindrical shaft 24. Is configured. At the time of image formation, each image forming unit is rotated by a transfer guide roller 9 for sequentially supporting the intermediate transfer belt 4.
The image forming position 25 can be located at the image forming position 25 opposite to the transfer position between the roller and the tension roller 5. The image forming position 25 is also an exposure position by the pixel laser signal light 26, and the image forming unit performs an image forming operation only at this position, and does not operate at other positions.

FIG. 5 shows the black image forming unit 21Bk and the yellow, magenta and cyan image forming units 21Y and 21Y.
M and 21C are shown. Each image forming unit differs only in the developer contained therein. Since the other components are the same, the image forming unit 21B for black is used to simplify the description.
k will be described and other colors will be omitted. In addition, the same reference numerals are assigned to the same parts for each color, and when it is necessary to distinguish the configuration of each color, a letter indicating each color is added to the reference numeral.

In FIG. 5, reference numeral 26 denotes a pixel laser signal light also shown in FIG. 1, 27 denotes an organic photoreceptor mainly composed of a polycarbonate binder resin using phthalocyanine as a photosensitive material, and 28 denotes a negative charge of the photoreceptor. A corona charger, 29 is a grid for controlling the charging potential of the photosensitive member to be constant, 30 is an exposure window which is an opening of the image forming unit through which the laser beam enters the image forming unit, and 31Bk is a black developing device. The developing device 31 includes a toner hopper 32 and a developing roller 3.
3, a magnet 34, a doctor blade 35 and the like. In the toner hopper 32, a black toner 36Bk of negative charge having a black pigment dispersed in a polyester resin is contained.

The black toner is mixed with a ferrite carrier having a particle diameter of 50 μm, the surface of which is coated with a silicon resin, and is carried as a two-component developer 37Bk on the surface of the developing roller 33 to develop the photoreceptor 27. 38 is a photoreceptor 2 after transfer
7 is a cleaner for cleaning toner remaining on the surface, and includes a cleaning blade 39 made of rubber and a waste toner reservoir 40 for storing waste toner. The photoreceptor 27 has a diameter of 30 mm and rotates in the direction of the arrow at a peripheral speed of 100 mm / s, and the developing roller 33 has a diameter of 16 mm and rotates at a peripheral speed of 140 mm / s. The fan-shaped spread angle of the image forming unit 21 is 90 degrees, which includes a cleaner section 38 of about 30 degrees and a developing unit 31 of about 6 degrees.
0 degrees.

Next, returning to FIG. Reference numeral 41 denotes a static elimination needle for preventing a toner image from being disturbed when the recording paper 42 is separated from the intermediate transfer belt 4. Reference numeral 43 denotes a retransfer roller serving as a retransfer unit, which is configured to abut on the retransfer backup roller 6 via the intermediate transfer belt 4. The retransfer roller 43 is configured to be rotatable 1.5% slower than the intermediate transfer belt 4 in order to prevent a dropout phenomenon when transferring a toner image. The arrow S indicates the contact direction of the retransfer roller 43 with the retransfer backup roller 6. The direction of the arrow S is configured to be perpendicular to the direction of the arrow R. For this reason, the guide groove 6
If the clearance between the first and second guide rollers 63 and 64 is set appropriately, the intermediate transfer belt 4 and the photosensitive member 2 at the transfer position can be used even if the re-transfer roller 43 is separated or moved during the image forming operation.
7 is hardly displaced.

Reference numeral 53 denotes a paper feeding unit which stores the recording paper 42 and is mounted on the lower part of the main body. Reference numeral 54 denotes a paper guide as a paper transport path for transporting the recording paper 42 from the paper feed unit 53 to the retransfer roller 43. 50 is a feeding roller.

Reference numeral 44 denotes a laser exposure device, which includes a semiconductor laser (not shown), a polygon mirror 45, a lens system 46,
It is composed of an intermediate mirror 47, a laser light emission window 55 and the like. The laser exposure device 44 is arranged such that the rotation surface of the polygon mirror 45 is positioned relative to a horizontal plane in a space surrounded by the image forming unit group 22, the intermediate transfer belt unit 2, the paper supply unit 53, and the paper guide 54 in the printer outer housing 1D. 4
It is arranged in a posture tilted twice. The intermediate mirror 47 is mounted so that its reflection surface faces downward by 12 degrees from the horizontal direction. 56C shows the outermost envelope when the image forming unit group 22 rotates and moves, and 56A shows the outermost envelope 56
A vertical line on the image forming position 25 side with respect to C is shown.

Reference numeral 56B denotes a vertical line from the contact position of the cleaning blade 7. Laser light emission window 5
5 is configured to be disposed between the vertical line 56A and the vertical line 56B. Reference numeral 49 denotes a center mirror, which is fixed in the shaft 24 such that its reflection surface faces down three degrees from the horizontal direction. The pixel laser signal light 26 corresponding to the time-series electrical pixel signal of the image information from the laser exposure device 44 enters the intermediate mirror 47 at an elevation angle of 42 degrees. The pixel laser signal light 26 reflected by the intermediate mirror 47 passes through the optical path window 48 formed between the cleaner 38Y of the yellow image forming unit 21Y and the developing device 31M of the magenta image forming unit 21M, and passes through the shaft 24. Incident on the center mirror 49 at an elevation angle of 18 degrees through a window opened in a part of
The image forming unit 21Y that is reflected and is at the image forming position 25
From the exposure window 30 into the image forming unit 21Y, and passes through a passage between the developing device 31Y and the cleaner 38Y which are disposed vertically in the image forming unit to the exposed portion on the left side surface of the photoreceptor 27Y. It is incident at an elevation angle of 12 degrees and is scanned and exposed in the generatrix direction.

Here, from the optical path window 48 to the center mirror 4
Since the optical path up to 9 utilizes the gap in the wall surface between the image forming units 21Y and 21M, the image forming unit group 22 has little wasted space. In addition, since the center mirror 49 is provided at the center of the image forming unit group 22, it can be constituted by a single fixed mirror, and has a simple configuration and easy alignment. In addition, the laser exposure device 44 arranges the rotation surface of the polygon mirror 45 in a space surrounded by the image forming unit group 22, the intermediate transfer belt unit 2, the paper supply unit 53, and the paper guide 54 with the rotation surface inclined with respect to the horizontal plane. Therefore, the configuration is easy to reduce the size by effectively utilizing the space in the device.

Further, since the laser light emission window 55 is disposed between the vertical line 56A and the vertical line 56B, even if toner spills from the image forming position 25 or the cleaning position during the image forming operation, the laser light is emitted. The emission window 55 is configured not to be easily contaminated with toner.

It is desirable that the inclination of the rotation surface of the polygon mirror 45 is large because the laser exposure device 44 can be arranged closer to the image forming unit group 22. However, tilting by 60 degrees or more can prevent the pixel laser signal light 2
It is not desirable because it becomes difficult to make the angle of incidence of 30 or less 30 degrees.

The intermediate mirror 47 and the center mirror 49
It is desirable that the incident angle of the pixel laser signal light 26 with respect to When the angle is 30 degrees or more, the aberration of the laser beam on the reflection surface becomes large, and the image quality may be deteriorated. Also,
Since the image forming position 25 and the laser exposure device 44 must be arranged separately, it is difficult to reduce the size.

The intermediate mirror 47 and the center mirror 49
The direction of the reflection surface is not limited, but it is preferable that the reflection surface is below a horizontal plane in order to minimize contamination by toner.

The pixel laser signal light 26 enters the center mirror 49 from a gap in the wall between the image forming units 21Y and 21M. That is, the developing device 3 of the image forming unit 21Y is sandwiched by the optical path of the pixel laser signal light 26 that is reflected by the center mirror 49 and enters the photoconductor 27Y (the path between the developing device 31Y and the cleaner 38Y).
The configuration is such that the pixel laser signal light 26 enters the center mirror 49 from the side opposite to 1Y. This is because, for example, in order to make the capacity of the frequently used black image forming unit 21Bk larger than that of other colors, the fan-shaped spread angle of the black image forming unit 21Bk is set to 120 degrees, yellow, magenta, and cyan. Even if the fan-shaped spread angles of the image forming units 21Y, 21M, and 21C are respectively set to 80 degrees, the breakdown is that the developing unit 31Bk is 90 degrees, the cleaner 38Bk is 30 degrees, and the developing units 31Y, 31M, and 31C are 50 degrees. When the cleaners 38Y, 38M, and 38C are 30 degrees, the capacity of the toner hopper 32Bk of the black image forming unit 21Bk can be increased without changing the arrangement of the other components described above.

Reference numeral 51 denotes a fixing device provided on the upper inside of the printer body 1.

The operation of the thus configured color electrophotographic apparatus will be described below.

First, the full-color image forming process will be described.
1 is in an image forming state. First, the yellow image forming process is performed. FIG. 5 shows the operation of the image forming unit 21Y.
This will be described with reference to FIG. The photoconductor 27 was charged to −450 V by the charger 28 that applied a voltage of −450 V to the grid 29. The photosensitive member 27 was irradiated with the pixel laser signal light 26 to form an electrostatic latent image. After passing through the lens system 46, the pixel laser signal light 26 is reflected twice by the intermediate mirror 47 and the center mirror 49 in a Z-shape (rearward in FIG. 1) and reaches the photoconductor 27. At this time, the exposure potential of the photoconductor was -50V.

This photoreceptor 27 was replaced with a two-component yellow developer 3
The developing was performed by a developing roller 33 carrying 7Y. When the photosensitive member 27 passed through the uncharged area, a DC voltage of +100 V was applied to the developing roller 33 by a high-voltage power supply. Thereafter, a DC voltage of -250 V was applied to the developing roller 33 by a high-voltage power supply when passing through the surface of the photoconductor 27 on which the electrostatic latent image was written by being charged to -450 V. As a result, a yellow-positive yellow toner image was formed only on the image portion on the photoconductor 27. At this time, the image forming unit group 22 is at the position shown in FIG.
Is at the image forming position 25 as shown in FIG.
Reference numeral 7 is in contact with the intermediate transfer belt 4.

In the image forming step of the image forming unit described above, an image was formed with yellow toner. At this time, the moving speed of the intermediate transfer belt 4 is set to be 1.5% faster than the speed of the photoconductor 27 in order to prevent the hollow transfer of the toner image. The image is transferred onto the transfer belt 4. At this time, the transfer guide roller 9 and the tension roller 5
V DC voltage was applied.

After the transfer of all the yellow toner images, the entire image forming unit group 22 is driven by the moving motor 23 to rotate exactly 90 degrees in the direction of arrow Q in FIG. 1 to move the image forming unit 21M to the image forming position. He stopped at 25.

When the rotation of the image forming unit group 22 is completed and the image forming unit 21M reaches the image forming position 25, the laser exposure device 44 irradiates a signal light to the image forming unit 21M with a magenta signal as before. Then, formation and transfer of a magenta toner image are performed. By this time, the intermediate transfer belt 4 has made one rotation, the timing of writing the magenta signal light is controlled based on the signal from the position detector 12, and the previously transferred yellow toner image is replaced with the next magenta toner image. Are superimposed so as to coincide in position. During this time, the re-transfer roller 43 is retracted to a position where the re-transfer roller 43 is not in contact with the intermediate transfer belt 4, so that the toner image on the transfer belt 4 is not disturbed.

Further, the cleaning unit 15 is provided as shown in FIG.
2, the cam follower 16 is pushed by the separation / contact cam 52 of the printer body 1 and rotates in the direction of the arrow P with the pivot 18 as a fulcrum, so that the cleaning blade 7 and the toner receiver 17 separate from the intermediate transfer belt 4. Therefore, the toner image on the transfer belt 4 is not disturbed. Further, the cleaning blade 7 is in contact with the overhang portion 4A of the intermediate transfer belt 4, and the toner receiver 17 is located closer to the intermediate transfer belt 4 than the tip of the cleaning blade 7 even when the cleaning blade 7 is separated. The waste toner adhering to the cleaning blade 7 does not spill out when the blade 7 is moved away.

Thereafter, the entire image forming unit group 22 is driven by the moving motor 23 again, rotates 90 degrees in the direction of arrow Q, and stops at the position where the image forming unit 21C reaches the image forming position 25. The same operation as for yellow magenta was performed for cyan.

Finally, the entire image forming unit group 22 is indicated by an arrow Q.
The image forming unit 21Bk was rotated 90 degrees in the direction, the image forming unit 21Bk was replaced with the image forming position 25, and an image was formed using black toner.
The four color toner images were superimposed on the intermediate transfer belt 4 in a position-matching manner, and a full-color image was formed. After the transfer of the last black toner image, the retransfer roller 43 is pressed against the retransfer backup roller 6, and a voltage of +3 kV is applied.
The four color toner images were collectively transferred onto the recording paper 42 fed from the paper feeding unit 53 to the paper guide 54. The toner image transferred to the paper was fixed by the fixing device 51.

Thereafter, the entire forming unit group 22 is driven by the moving motor 23 and further rotated by 90 degrees in the direction of arrow Q in FIG. 1, and the yellow image forming unit 21Y reaches the image forming position 25 again, and is newly formed. The process of creating a full-color image has begun.

In this way, 2.5 full-color A4 size prints were obtained in one minute.

Next, the attachment / detachment operation of the intermediate transfer belt unit 2 and the image forming unit 21 will be described. When the front plate 1A is turned down as shown in FIG. 2, the opening 71 is opened.
When the intermediate transfer belt unit 2 is inserted toward the opening 71, the guide grooves 61 and 62 and the guide pins 63 and 64 are inserted.
And the intermediate transfer belt unit 2 is guided to a predetermined storage position while being guided in the direction of arrow R.

Since the opening 71 for the paper jam processing also serves as the insertion opening of the intermediate transfer belt unit 2, the insertion opening of the intermediate transfer belt unit 2 having a large projected area from above is separately provided on the upper surface of the printer main body 1. It is a configuration that does not need to be provided. The direction of the guide is obliquely forward and downward when viewed from the operator, so that the guide can be easily mounted in a natural posture.
Further, since the insertion direction is toward the center mirror 49, the intermediate transfer belt 4 comes into contact with the photoconductor 27 from its normal direction, so that the photoconductor 27 does not need to be retracted when it is attached or detached. The body 27 and the intermediate transfer belt 4 are not damaged. Since the intermediate transfer belt unit 2 has a cross-sectional shape narrowing toward the center mirror 49, it can be easily inserted into the opening 71. It is possible to increase the capacity of the waste toner reservoir 10 while reducing the center distance between the transfer guide roller 9 and the tension roller 5 so that the positioning of the intermediate transfer belt 4 with respect to the photoconductor 27 and the contact pressure can be easily set appropriately. It is a configuration that can be done.

In conjunction with the insertion operation, the separation / contact cam 52 of the printer main body 1 and the cam follower 16 engage to separate the cleaning blade 7 from the intermediate transfer belt 4. In a normal stop or standby state, the cleaning blade 7 is separated from the intermediate transfer belt 4. Then, only when cleaning is necessary, the separating / contacting cam 52 rotates to bring the cleaning blade 7 into contact with the intermediate transfer belt 4.

When the intermediate transfer belt unit 2 is removed, the engagement between the separation / contact cam 52 and the cam follower 16 is released.
The cleaning blade 7 is in contact with the intermediate transfer belt 4 to prevent scattering of waste toner. The angle between the direction of removal (opposite to the arrow R) and the direction of pressing of the separating / contacting cam 52 shown by the arrow V in FIG. 1 is 90 degrees or less, so that the removal can be performed smoothly without giving unnecessary resistance.

Further, the image forming unit 21 is opened by opening the printer upper plate 1C, and the unit other than the image forming position 25 (here, the black image forming unit 21B
k). For this reason, it is possible to attach / detach without damaging the photosensitive member 2 and the intermediate transfer belt 4 without performing an operation of retracting the photosensitive member 27 when attaching / detaching. In the present embodiment, it is configured to be inserted substantially in the direction of gravity. Since the projected area from above is smaller than that of the intermediate transfer belt unit 2, the operation is easy even from the front of the apparatus. This attaching / detaching direction is desirably 30 degrees or more and 90 degrees or less with respect to the attaching / detaching direction of the intermediate transfer belt unit 2. If the angle is less than 30 degrees, the capacity of the toner hopper 32 of the developing device 31 at the image forming position 25 cannot be sufficiently secured, and if the angle is more than 90 degrees, the operator inserts from the back to the front, which is very convenient. Is worse.

As described above, according to the first embodiment, the laser exposure device 44 is disposed in the space surrounded by the image forming unit group 22, the intermediate transfer belt unit 2, the paper transport path 54, and the paper supply unit 53. With such a configuration, a compact color electrophotographic apparatus can be realized by effectively utilizing the space in the apparatus.

At the time of image recording, the pixel laser signal light 2
6 is reflected by the center mirror 49 and sandwiches the path leading to the image forming position 25, and the photosensitive member 27 at the image forming position 25 is separated.
From the side opposite to the developing unit 31 acting on the pixel laser signal light 2
6 is incident on the center mirror 49,
It is possible to realize a small-sized color electrophotographic apparatus capable of increasing the capacity of the toner hopper 32 of the frequently used color developing unit 31 without changing the arrangement of other components.

Further, by arranging the rotation surface of the polygon mirror 45 of the laser exposure device 44 at an angle of 60 degrees or less with respect to the horizontal plane, the space in the device can be more effectively used, and a compact color electrophotographic apparatus can be used. Can be realized.

Further, a cleaning blade 7, which is a belt cleaning means for removing toner remaining on the intermediate transfer belt 4, is provided inside the intermediate transfer belt unit 2.
The laser light emission window 55 of the laser exposure device 44 is connected to the vertical line 56A on the image forming position 25 side with respect to the outermost envelope 56C of the image forming unit group 22 in the side view of the printer 1.
And between the cleaning blade 7 and the vertical line 56B from the cleaning position of the intermediate transfer belt 4, so that even if toner spills from the image forming position 25 or the cleaning position during the image forming operation, the laser light exit window It is possible to realize a small-sized color electrophotographic apparatus in which the toner 55 is not easily contaminated with toner.

Further, the intermediate transfer belt unit 2 is configured to be detachable from the printer main body 1, the retransfer means is a retransfer roller 43 provided on the printer main body 1, and the intermediate transfer belt unit 2 Guide grooves 61 and 62 and guide pins 63 and 64, which are belt unit guide means for guiding to the storage position, and an intermediate transfer belt unit 2
And a re-transfer backup roller 6 with which the re-transfer roller 43 is in contact, and a guide groove 61 at a predetermined storage position.
The configuration in which the guide direction of the intermediate transfer belt unit 2 by the guide pin 62 and the guide pins 63 and 64 is substantially perpendicular to the direction of the pressing force when the retransfer roller 43 contacts the retransfer backup roller 6 is used. By making the belt unit replaceable from the front, it is possible to realize a small-sized color electrophotographic apparatus with less misalignment for each color while improving maintainability.

Further, since the intermediate transfer belt unit 2 has a sectional shape narrowing toward the center mirror 49, the intermediate transfer belt unit 2 is
1 while reducing the distance between the axes of the transfer guide roller 9 and the tension roller 5 while keeping the waste toner reservoir 1
Therefore, a small color electrophotographic apparatus having a long maintenance interval can be realized.

Further, there is provided an intermediate mirror 47 which folds the pixel laser signal light 26 toward the center mirror 49, and irradiates the photosensitive member 27 at the image forming position 25 with the intermediate mirror 47 and the center mirror 49.
Is folded back so as to form a substantially Z-shape, the image forming position 25 and the laser exposure device 44 can be arranged close to each other, and a compact color electrophotographic apparatus can be realized.

Further, the angle of incidence of the pixel laser signal light 26 on the intermediate mirror 47 and the center mirror 49 is set to 30
With the configuration of not more than the degree, the aberration of the laser beam on each reflecting surface can be suppressed, and the image forming position 25 and the laser exposure device 44 can be arranged close to each other, so that a compact color electrophotographic apparatus can be realized. .

Further, the intermediate transfer belt unit 2 is configured to be detachable from the printer main body 1, and the opening 71 of the intermediate transfer belt unit 2 is engaged with the intermediate transfer belt unit 2 so that the intermediate transfer belt unit 2 is moved. It is provided with guide grooves 61 and 62 and guide pins 63 and 64 which are belt unit guide means for guiding from the opening 71 to a predetermined storage position, and the guide grooves 61 and 62 and the guide pins 63 and 64 are provided.
, The guide direction of the intermediate transfer belt unit 2 is in a range from the horizontal direction around the center mirror 49 to the upper end 57 of the opening, so that the intermediate transfer belt unit 2 can be easily mounted in a more natural posture than the front surface. In addition, it is possible to realize a small-sized color electrophotographic apparatus in which the photosensitive member 27 and the intermediate transfer belt 4 are not damaged even if the photosensitive member 27 is not evacuated during attachment / detachment.

Further, the insertion port 72 of the image forming unit 21
And the image forming unit 21 engaged with the image forming unit 21.
Of the image forming unit 21 by the guide pins 67, 68 and the guide grooves 69, 70, which are image forming unit guide means for guiding the image forming unit 21 to a predetermined position of the image forming unit group 22. The configuration in which the guide direction is in a range of 30 degrees or more and 90 degrees or less with respect to the guide direction of the intermediate transfer belt unit 2 ensures a sufficient capacity of the toner hopper 32 and is small in color with good operability from the front. An electrophotographic apparatus can be realized.

Embodiment 2 FIG. 6 shows a configuration of a color electrophotographic apparatus according to Embodiment 2 of the present invention.

The difference from the configuration of FIG.
3 is provided so as to protrude from the front surface of the printer body 1;
The rotation surface of the polygon mirror 45 is inclined by 18 degrees with respect to the horizontal plane, and the laser exposure device 44 is disposed in a space surrounded by the image forming unit group 22, the intermediate transfer belt unit 2, and the paper guide 54 on three sides. It is. In this case, the reflection surface of the intermediate mirror 47 is oriented in the horizontal direction.

Other structures and operations are the same as those of the first embodiment.

As described above, according to the second embodiment, the actual installation area is larger than that of the first embodiment by the projection of the sheet feeding unit 53, but the height of the printer body 1 is kept low. be able to.

In the above description, an example in which the four color image forming units 21 of black, yellow, magenta, and cyan are used, but the types and numbers of colors are not limited. Further, image forming units having different capacities may be used.

Although the diameter of the photosensitive member 27 is 30 mm and the peripheral speed is 100 mm / s, the diameter and the peripheral speed of the photosensitive member are not limited. Further, the process conditions such as the developing method, the applied voltage, and the peripheral speed of the intermediate transfer belt 4 are not limited to those in the embodiment, and for example, a non-magnetic one-component developing process may be used.

The structure of the intermediate transfer belt unit 2 is not limited to the structure shown in the embodiment. Center mirror 4
As long as it has a shape narrowing toward 9, the shape is arbitrary. Further, the number and diameter of the rollers that stretch the intermediate transfer belt 4 are not limited. Further, the belt cleaning means is the cleaning blade 7, but the belt cleaning means and its position are also arbitrary. When the intermediate transfer belt 4 does not need to be replaced, such as when the life of the intermediate transfer belt 4 is about the same as the life of the printer main body 1, the intermediate transfer belt unit 2 is detachable from the printer main body 1. You don't have to.

Although the retransfer means is the retransfer roller 43, other transfer means such as a corona charger may be used.

Further, in the first embodiment, the guide direction (arrow R) of the intermediate transfer belt unit 2 is linear, but the guide direction may be curved. In this case, the direction of the tangent to the guide direction is the horizontal line 65 and the line 6
It is good if it is between 6. Further, the guide direction (arrow T) of the image forming unit 21 is also linear, but it may be curved like the intermediate transfer belt unit 2.
Also in this case, the tangent of the image forming unit 21 in the guide direction may be 30 degrees or more and 90 degrees or less with respect to the guide direction of the intermediate transfer belt unit 2. However, the guide direction at the time of positioning with respect to the image forming unit group 22 is arbitrary. For example, the image forming unit 21 is inserted in the direction of arrow T, and finally the image forming unit 21 is
May be rotated to bring the guide pin 68 into contact with the positioning reference.

The contact direction (arrow S) of the retransfer roller 43 with respect to the retransfer backup roller 6 is perpendicular to the guide direction (arrow R) of the intermediate transfer belt unit 2. May be perpendicular to the guide direction when the intermediate transfer belt unit 2 is at the predetermined storage position. The direction during which the intermediate transfer belt unit 2 is inserted and guided to a predetermined storage position is not limited.

In the second embodiment, the laser exposure device 44 is disposed on the three sides in a space surrounded by the image forming unit group 22, the intermediate transfer belt unit 2, and the paper guide 54. Only needs to include two thirds or more of the above space.

[0093]

As described above, according to the present invention, it is possible to realize a color electrophotographic apparatus or an intermediate transfer belt unit which is easy to maintain and has small positional deviation for each color.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a method for attaching and detaching each unit of the color electrophotographic apparatus according to the embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating a configuration of an intermediate transfer belt unit used in the color electrophotographic apparatus according to one embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration of an intermediate transfer belt used in the color electrophotographic apparatus according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of an image forming unit used in a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a color electrophotographic apparatus according to Embodiment 2 of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a conventional color electrophotographic apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printer main body 1A Front plate 1B Hinge shaft 1C Top plate 1D Printer outer casing 2 Intermediate transfer belt unit 3 Unit case 3A Surface defining cross-sectional shape 3B Surface defining cross-sectional shape 4 Transfer belt 4A Overhang portion 5 Tension roller 6 Re Transfer backup roller 7 Cleaning blade 8 Drive roller 9 Transfer guide roller 10 Waste toner reservoir 11 Waste toner full detector 12 Position detector 15 Cleaner unit 16 Cam follower 17 Toner receiver 18 Oscillating shaft 19 Communication port 20 Detection hole 21 Image forming unit 22 Image forming unit group 23 Moving motor 24 as a means for moving image forming unit group 22 Axis 25 Image forming position 26 Pixel laser signal light 27 Organic photoreceptor 28 Corona charger 29 Grid 30 Exposure window 31 Developing device 32 Toner hot Par 33 developing roller 34 magnet 35 doctor blade 36 toner 37 two-component developer 38 cleaner 39 cleaning blade 40 waste toner reservoir 41 static elimination needle 42 recording paper 43 retransfer roller as retransfer means 44 laser exposure device 45 polygon mirror 46 lens system 47 Intermediate mirror 48 Optical path window 49 Center mirror 50 Feeding roller 51 Fixing device 52 Separation / contact cam 53 Paper feed unit 54 Paper guide as a paper conveyance path 55 Laser light emission window 56A Image formation position 25 side with respect to outermost envelope 56C Vertical line 56B Vertical line 56C from the contact position of the cleaning blade 7 56C Outermost envelope when the image forming unit group 22 rotates and moves 57 Upper end of the opening 71 61 Guide groove as a guide means of the intermediate transfer belt unit 2 62 Intermediate transfer belt Guide groove as guide means for knit 2 63 Guide pin as guide means for intermediate transfer belt unit 2 64 Guide pin as guide means for intermediate transfer belt unit 2 65 Horizontal line drawn from center mirror 49 66 Opening from center mirror 49 A line connecting the upper end 57 of the image forming unit 71 with a guide 67 A guide pin 68 as a guide for the image forming unit 21 A guide pin 69 as a guide for the image forming unit 21 A guide groove 70 as a guide for the image forming unit 21 70 Guide groove 71 as a guide means Opening opening when front plate 1A is folded down 72 Insertion opening of image forming unit 101 Intermediate transfer belt unit 102 Intermediate transfer belt 103 First transfer roller 104 Second transfer roller 105 Cleaner roller 106 Waste Tona Reservoir 107 image forming unit 108 image forming unit group 109 shaft 110 image forming position 111 laser beam 112 laser exposure device 113 the optical path window 114 mirror 115 exposure window 116 developing device 117 cleaner 118 photosensitive drum 119 third transfer roller 120 fuser

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Asakura 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-7-287502 (JP, A) JP-A-6-205 138744 (JP, A) JP-A-7-43972 (JP, A) JP-A-7-36245 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/01 G03G 15 / 01-15/01 117 G03G 15/16

Claims (6)

(57) [Claims] An image forming unit that forms a toner image on a photoconductor, an intermediate transfer belt that transfers a toner image formed on the photoconductor to form a color image, and supports the intermediate transfer belt unit. An intermediate transfer belt unit, which is provided in a storage unit provided in the apparatus, including a backup roller, and is provided so as to be able to contact and separate from the intermediate transfer belt, and has transferred a color image from the photoconductor to the intermediate transfer belt. And a retransfer roller that abuts the transfer belt unit at a position facing the backup roller to transfer a color image from the intermediate transfer belt to recording paper; and an intermediate transfer provided on the intermediate transfer belt and mounted on the apparatus. A unit guide means for a belt unit, and an apparatus guide provided in the apparatus for guiding the intermediate transfer belt unit to the predetermined position. And a belt unit guide unit having a belt unit guide unit, wherein when the intermediate transfer belt unit is housed in the housing unit, the retransfer roller is located at a separated position different from the retransfer position. The intermediate transfer belt unit is accommodated while being guided by the guide unit of the apparatus in a direction perpendicular to the photoconductor rotation axis with respect to the photoconductor, and recording is performed from the intermediate transfer belt unit accommodated in the accommodation unit. When re-transferring to paper, the intermediate transfer belt is moved so that the re-transfer roller moves upward from below and the pressing force against the intermediate transfer belt is substantially perpendicular to the guide direction of the intermediate transfer belt unit. A color electrophotographic apparatus, characterized in that the apparatus is configured to be in contact with. 2. The belt unit guide means comprises a guide groove and a guide pin, wherein the guide pin is guided by the guide groove only in a direction perpendicular to a rotation axis of the photoconductor relative to the photoconductor. Item 1. A color electrophotographic apparatus according to Item 1. 3. The apparatus main body includes: an image forming unit group rotatably supporting the image forming unit; an intermediate transfer belt unit onto which a color image is transferred; and a color image on recording paper re-transferred from the intermediate transfer belt. A fixing unit for fixing, a sheet feeding unit provided below the intermediate transfer belt unit, the image forming unit group, and the fixing unit and at a lower portion of the apparatus main body; and a recording sheet in the sheet feeding unit is fed. A feed roller, a paper transport path for transporting recording paper, a paper guide provided in the apparatus main body, for transporting the recording paper fed from the feed roller, and a front plate that can be opened and closed by the apparatus main body. And a paper transport path having a transport path that is continuous with the paper guide. When the intermediate transfer belt unit is mounted on the apparatus main body, the front plate is opened and the intermediate transfer belt unit is opened. 2. The collar according to claim 1, wherein the conveying path is released from a predetermined position such that the sheet feeding unit, the feeding roller, and the paper guide are kept at the predetermined positions so that the paper feeding unit is guided by the guide means of the apparatus. Electrophotographic equipment. 4. An apparatus main body comprising: an image forming unit group rotatably supporting the image forming unit; a laser exposure apparatus for exposing a photosensitive member; an intermediate transfer belt unit on which a color image is transferred; A fixing device for fixing the color image on the re-transferred recording paper; a sheet feeding unit provided below the intermediate transfer belt unit, the image forming unit group and the fixing device, and below the apparatus main body; A paper discharge unit provided above the belt unit and the image forming unit group and on the upper surface of the apparatus main body, and a paper conveyance path for conveying recording paper from the paper supply unit to the paper discharge unit. The paper feed unit and the paper discharge unit are provided so as to correspond to each other with the intermediate transfer belt unit and the image forming unit group interposed therebetween, and the paper feed unit, the paper transport path, and the like are provided. In the space formed by the fine the discharge unit, the intermediate transfer belt unit, a color electrophotographic apparatus according to claim 1 or 3 configured so that the image forming unit group and the laser exposure apparatus is arranged. 5. A sheet feeding unit, a sheet discharging unit, and the image forming apparatus, further comprising a front plate provided on a side different from the image forming unit group with respect to the intermediate transfer belt unit so as to be openable and closable with respect to the apparatus main body. The accommodation space of the intermediate transfer belt unit surrounded by the forming unit group is
The intermediate transfer belt unit is configured to appear when the front plate is opened. The intermediate transfer belt unit is detachably housed in a housing space of the intermediate transfer belt unit that appears when the front plate is opened. The color electrophotographic apparatus according to claim 4. 6. An intermediate transfer belt on which a toner image formed on a photoreceptor is transferred to form a color image, a backup roller for supporting the intermediate transfer belt unit, and guide means for mounting to the apparatus. The guide direction of the apparatus main body to the housing unit by the guide means of the apparatus main body is perpendicular to the rotation axis of the photoconductor, and
A transfer roller for transferring a color image onto a recording sheet, which is set so as to be substantially perpendicular to a direction of a pressing force when the transfer roller contacts the intermediate transfer belt; Belt unit.