JP2002023430A - Both-side image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To incorporate a manual paper feeder with a both-side image forming device which is constituted so that a transfer material may be carried in a vertical direction. SOLUTION: The paper feeding table 61 of a manual paper feeding part 60 is nearly horizontally arranged in a space above a paper feeding cassette 15, on the other hand, the carrying surface of the transfer material including the image transfer area 14b of an intermediate transfer belt 14a is arranged with inclination so that the elevation angle, that is, an angle to a horizontal plane may be equal to or below a right angle, for example, about 70 deg., then, both of the transfer material manually fed from the paper feeding table 61 and a recording paper P which is automatically fed from the paper feeding cassette 15 are carried onto the intermediate transfer belt 14a through a lenient paper feeding path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided image forming apparatus of the type in which a toner image is transferred to both sides of a transfer material and fixed at the same time, and more particularly to a double-sided image forming apparatus in which the transfer of the transfer material is performed in a vertical direction. .

[0002]

2. Description of the Related Art In a conventional double-sided image forming apparatus, a transfer material re-feeding mechanism is provided in an apparatus main body. A method is adopted in which the sheet is turned upside down by a sheet re-feeding mechanism, fed again, the toner image on the back side of the document is transferred to the other side, and the image is formed again by passing through a fixing device.

[0003] However, in such a system, the transfer distance of the transfer material is remarkably long, so that not only a long time is required for the image forming time, but also a lot of troubles occur such as jamming. There is a problem that the paper quality is damaged by the heating and the quality of the copy deteriorates.

[0004]

Instead of the above-mentioned method,
For example, the toner image on the back side of the document previously formed on the image forming body is once transferred to and carried on the intermediate transfer body, and then the toner image on the front side of the document formed on the image forming body is adhered on the intermediate transfer body. Is transferred to the surface of the transfer material fed in a state in which the transfer material is fed, and then the toner image on the back surface of the original document carried on the intermediate transfer body is retransferred to the back surface of the transfer material. A double-sided image forming apparatus capable of simultaneously fixing a toner image has been proposed.

[0005] A belt-shaped intermediate transfer member is used in such an apparatus. However, since a peripheral length longer than at least an image is required, a floor area occupied by the apparatus is required to be large. As a countermeasure, a so-called vertical structure in which transfer material is set up and down in order to reduce the floor area occupied by the apparatus and to discharge paper into the apparatus body has been studied.

As a result, after the transfer material is fed from a cassette or the like, the transport path is bent to an angle close to a right angle. In particular, when a thick transfer material is fed manually, the flatness of the transfer material is reduced. There is a possibility that the transfer performance may be deteriorated or the transfer performance may become unstable.

The present invention solves this problem and as a result, as a result, even in a double-sided image forming apparatus in which the transfer material conveyance path is set in a vertical direction, a thick transfer material can be fed safely and accurately to form an image. The purpose of the present invention is to provide a double-sided image forming apparatus that can perform the image forming operation.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide a double-sided image forming apparatus in which a toner image formed on an image forming body is fixed on both front and back surfaces of a transfer material via an intermediate transfer belt and then fixed. The toner image is formed on the front and back surfaces during the process of being conveyed upward by the intermediate transfer belt after being carried out from a paper cassette installed substantially horizontally, and is discharged in a substantially horizontal direction while being discharged. A two-sided image forming apparatus (invention according to claim 1), wherein the transfer material to be fed is fed to the intermediate transfer belt from a substantially horizontal manual feed portion provided above the feed cassette. And a two-sided image forming apparatus that performs fixing after transferring the toner image formed on the image forming body to both the front and back surfaces of the transfer material via an intermediate transfer belt, wherein the transfer material is supplied from a paper cassette installed substantially horizontally. Issued, along with the paper ejection inverted substantially horizontally formed toner images on both surfaces in the course of being transported upwards by the intermediate transfer belt,
The transfer material fed manually is conveyed into the apparatus from a manual paper feed unit provided opposite the paper feed cassette, and fed to the intermediate transfer belt via a reversing paper feed unit. This is achieved by a double-sided image forming apparatus (the invention according to claim 5).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present invention, functions and structures common to the double-sided image forming apparatuses of the embodiments of the present invention will be described.

The image forming apparatus shown in FIGS. 1 and 3 is a double-sided image forming apparatus that transfers a monochrome image to both sides of a transfer material and simultaneously fixes the monochrome image. This is a so-called vertical double-sided image forming apparatus in which the conveying surface of an intermediate transfer belt to be used is arranged vertically.

In FIGS. 1 and 3, reference numeral 10 denotes a photosensitive drum which is an electrostatic latent image carrier, for example, an OPC photosensitive member composed of an organic photoconductive layer applied on a conductive drum and grounded. It is driven and rotated counterclockwise. Reference numeral 11 denotes a charger which applies, for example, a negative uniform charge to the peripheral surface of the photosensitive drum 10 by corona discharge to give a potential of V _H.
PCL using a light emitting diode or the like to remove the history of the photoreceptor up to the previous print prior to charging by 1
Exposure by 11a is performed to remove static electricity from the peripheral surface of the photoconductor.

After the photosensitive drum 10 is uniformly charged, the laser writing device 12 performs image exposure based on an image signal. In this image exposure, an image signal corresponding to image data of the front and back of a document input from a computer or an image reading device is processed by an image signal processing unit, and then input to a laser writing device 12 to be placed on a photosensitive drum 10. An electrostatic latent image is formed.

The laser writing device 12 includes a rotating polygon mirror 12b that rotates by using a laser diode (not shown) as a light source.
The optical path is bent by a plurality of reflecting mirrors 12d through the fθ lens 12c and the like to perform main scanning, and an electrostatic latent image is formed by the main scanning and the sub-scanning by the rotation of the photosensitive drum 10. In the present embodiment, the image portion is exposed based on the image signal corresponding to the above-described back side image, and the exposed portion forms a reversal latent image in which the absolute value of the potential is _VL which is low.

A developing device 13 containing a two-component developer composed of a negatively charged conductive toner and a magnetic carrier is provided around the periphery of the photosensitive drum 10, and a magnet is built in to hold the developer. The reversal development is performed by the rotating developing sleeve 13a.

The developer includes a carrier having ferrite as a core and an insulating resin coated around the core, a toner having a weight average particle diameter of 3 to 10 μm to which a pigment or a coloring agent such as carbon black is added, a charge controlling agent, silica , Titanium oxide, etc., and mixed so that the toner concentration becomes 5 to 10% by mass.
It is regulated to a layer thickness of 6 mm and transported to the development zone.

The gap between the developing sleeve 13a and the photosensitive drum 10 in the developing zone is larger than the layer thickness of the developer.
As 2～1.0Mm, applies an AC bias voltage obtained by superposing an AC voltage V _AC to a DC voltage V _DC between the developing sleeve 13a and the photosensitive drum 10. Since charging of the toner is a DC voltage V _DC of the same polarity (negative), the toner given the opportunity to leave from the carrier by the AC voltage V _AC, the part of the high V _H absolute value of the potential from the DC voltage V _DC And the toner amount corresponding to the potential difference adheres to the portion of _VL where the absolute value of the potential is low, and the image is visualized (reversal development).
Further, only the DC voltage _VDC may be applied between the developing sleeve 13a and the photosensitive drum 10. The development may be contact development. The photosensitive drum 10 holding the toner image is transferred in the next transfer step.

The toner image of the back side image formed on the photosensitive drum 10 by the above-described image forming process is a primary transfer unit 14 to which a transfer bias having a polarity opposite to that of the toner is applied.
c, the intermediate transfer belt 14 that is stretched between the driving roller 14d and the driven roller 14e and is driven and rotated clockwise.
a. The toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is removed and cleaned by the contact of the blade 19a of the cleaning device 19.

After the toner image serving as the backside image is formed on the intermediate transfer belt 14a as described above, the toner image serving as the backside image is continuously formed on the photosensitive drum 10 by the same image forming process as the backside image. Is done. At this time, the front surface image is formed on the photosensitive drum 10 so as to be synchronized with the back surface image transferred to the intermediate transfer belt 14a in the transfer area 14b. The image data of the front and back images is changed in advance so that the front image has a mirror image relationship with the back image on the photosensitive drum 10.

On the other hand, the paper feed cassette 15A or 15B
After the recording paper P, which is a transfer material, is conveyed through the unloading roller 16 and once waited by the timing roller 17, it is fed to the transfer area 14 b by the start of the rotation operation of the timing roller 17 when the transfer timing is adjusted. You.

The recording paper P is conveyed in close contact with the belt surface by the discharge of the paper charger 18, and a transfer bias having a polarity opposite to that of the toner is applied by the transfer unit 14c. The surface image formed thereon is transferred, and an AC bias for static elimination is applied by a paper separator 14f, separated from the drum surface and transported in close contact with the belt surface, and then the recording paper is transferred by the secondary transfer device 14g. By applying a transfer bias having a polarity opposite to that of the toner from the front side of P, the back side image transferred onto the intermediate transfer belt 14a is transferred to the back side of the recording paper P, and separated from the belt surface by a paper separator 14h. The intermediate transfer belt 14a, which has been conveyed toward the fixing device 20 and has separated the recording paper P, is cleaned by a cleaning device 119 to remove residual toner on the belt surface.

The intermediate transfer belt 14a is inclined so that the conveying surface of the recording paper P is not a vertical surface but has an elevation angle of 70 ° ± 15 °, so that the paper feed cassettes 15A and 15B located at a substantially horizontal position are provided. The fed recording paper P is fed smoothly and smoothly to the belt surface, and after being separated from the belt surface, the conveying direction is maintained by the guide means 30 provided downstream of the belt surface to accurately feed the fixing device 20 to the fixing device 20. Conveyed.

The guide means 30 has a plurality of spurs 3 on the front.
1 and a duct-shaped container 33 having a propeller fan 32 disposed on the rear surface thereof, and the intermediate transfer belt 14a
The recording paper P further separated is the intermediate transfer belt 14a described above.
Of the propeller fan 32
Is transported to the fixing device 20 while maintaining a normal transport direction without being lifted from the spur 31 by the appropriate suction force.

The propeller fan 32 stabilizes the conveying surface of the recording paper P and simultaneously passes harmful ozone generated by discharge of the transfer unit and the separator or high-temperature air radiated from the fixing device 20 through a filter (not shown). Duct 3
It is also discharged to the outside of the side door 40 through 4 and has the effect of maintaining the environment inside and outside the device normally.

The recording paper P is conveyed to the fixing device 20 via the above-mentioned guide means 30, and is provided with a heat roller 20A provided opposite thereto.
The toner images on the front and back sides are simultaneously welded by the sandwiching heating by the heating device 20B and turned upside down, and the surface image is discharged downward on the tray on the upper surface of the apparatus via the paper discharge roller 21, that is, in a page order.

The intermediate transfer belt 14a has a thickness of 0.5
An endless rubber belt of about 2.0 mm, a semiconductive substrate of silicon rubber or urethane rubber having a resistance of 10 ⁸ to 10 ¹² Ω · cm, and a thickness as a toner filming prevention layer outside the rubber substrate. It has a two-layer structure with a fluorine coating of 5 to 50 μm, and this layer also preferably has the same semiconductivity, and preferably has a surface resistance of 10 ⁸ to 10 ¹² Ω / cm ² . In addition, instead of the rubber belt base, a thickness of 0.
1 to 0.5 mm semiconductive polyester, polystyrene, polyethylene, polyethylene terephthalate, polyimide and the like can also be used.

FIGS. 2 and 4 correspond to FIGS. 1 and 3, respectively.
The intermediate transfer belt 14 is stretched between the driving roller 14d and the driven roller 14e.
a is sandwiched between a transfer substrate 14c, a paper separator 14f, a cleaning device 119, and a support substrate 50 integrated with the guide means 30, and has a predetermined angle with a support shaft 50A provided between the device substrates as a fulcrum. It is supported so that it can swing freely.

On the other hand, the release lever 5 which is urged clockwise by the return spring 53 and the tension spring 56 with the shaft 50B as a fulcrum and occupies the position shown in FIG.
1 and a locking lever 54 are provided.

When the locking lever 54 is in the position shown in the figure, the notch 55 at the tip of the locking lever 54 engages the outer end of the rotation support shaft 114e of the driven roller 14e projecting from the support substrate 50 on the rear side. Thus, the intermediate transfer belt 14a, the transfer unit 14c, the paper separator 14f, the guide unit 30, and the like are respectively set on the conveying surface of the recording paper P and are held at positions where image formation is possible.

The main body of the apparatus is opened up wide as shown by slightly lifting and rotating the side door 40 along the elongated hole 42 engaging with the guide pin 41, and the release lever 51 is folded. By pressing the bent portion 51A, the pressing pin 52 rotates the locking lever 54 counterclockwise.
As a result, the support substrate 50 is released when the outer end of the rotation support shaft 114e is disengaged from the notch 55 of the locking lever 54 and becomes free. The transport surface of the paper P is widely opened, and maintenance such as removal of jammed paper can be easily and safely performed.

(Embodiment 1) An embodiment of the invention according to claim 1 will be described with reference to FIG.

The feeding of the transfer material to the double-sided image forming apparatus is performed by the manual sheet feeding unit 6 provided above the sheet feeding cassette 15 in addition to the automatic sheet feeding from the respective sheet feeding cassettes 15 described above.
Feeding by manual feed from 0 is possible.

The manual paper feed unit 60 includes a paper feed table 61, a paper feed roller 62, and a dedicated timing roller 17A having the same function as the timing roller 17 provided on the paper feed cassette 15 described above. Have been.

When the transfer material is manually fed along the paper feed table 61 and its leading edge is detected by the photosensor S, the detection signal causes the paper feed operation of the recording paper P from the paper feed cassette 15 side. The paper feed roller 62 on the manual paper feed unit 60 side is started to operate, and at the same time, the timing roller 1
7A is switched to the standby state.

As the transfer material fed manually, thick paper having strong so-called "stiffness" or a material having high rigidity other than paper, which is difficult to automatically feed, may be used. As described above, the intermediate transfer belt 14a is used. Since the conveying surface is inclined in the range of 70 ° ± 15 °, the sheet feeding path is gentle, the sheet feeding operation is performed smoothly, and there is little possibility that a conveyance failure occurs.

When the present inventor tried an experiment of manual paper feed for various transfer materials, if the elevation angle of the conveyance surface of the intermediate transfer belt 14a could be set within a range of 70 ° ± 15 °, a commonly used thick paper was used. Many of the transfer materials can be fed, including
Further, the sheet feeding table 61 can be provided with a dip of 10 ° ± 10 ° to facilitate the sheet feeding operation on the sheet feeding table 61.

(Embodiment 2) An embodiment of the invention according to claim 5 will be described with reference to FIG.

The transfer material is supplied to the double-sided image forming apparatus in addition to the automatic paper supply from each of the paper supply cassettes 15 described above. Manual paper feed unit 60A provided on the opposite side
The paper can be fed by hand.

The manual sheet feeding section 60A is provided with a sheet feeding table 61A integrated with the side door 40, a sheet feeding guide 63, a sheet feeding roller 62A, and a sheet feeding path for automatic sheet feeding from the sheet feeding cassette 15. The reversing sheet feeder 64 and the reversing sheet feeding roller 62B are disposed on the intersecting manual sheet feeding path.

When the transfer material is manually fed along the paper feed table 61A and its leading end is detected by the photo sensor SA, the feed operation of the recording paper P from the paper feed cassette 15 is stopped by the detection signal. Then, the paper feed roller 62A on the side of the manual paper feed unit 60A starts operating, and at the same time, the reversing paper feed roller 62B and the timing roller 17A are switched to the standby state.

The transfer material fed by manual feed travels straight across the paper feed path of automatic paper feeding, and when the leading end is detected by the photo sensor SB, the reverse feed roller 62B is rotated clockwise by the detection signal. Then, the transfer material is conveyed leftward on the drawing along the reversing sheet feeding table 64, and when the rear end is detected by the photo sensor SB, the reversing sheet feeding roller 62B is rotated in reverse by the detection signal, and the guide plate 65 is simultaneously moved. The transfer material shifts from the position indicated by the solid line to the position indicated by the broken line, and therefore, the transfer material moves rightward in FIG.
, And waits for transfer of the toner image. When the sheet feeding operation by the timing roller 17A is started, the respective operations associated with the manual sheet feeding described above are canceled, and the guide plate 65
Is returned to the position shown by the solid line again.

As the transfer material fed manually, thick paper having a strong so-called "stiffness", which is difficult to automatically feed, or a material having high rigidity other than paper may be used, but as described above, the intermediate transfer belt 14a is used. In addition to the fact that the feeding surface of the sheet is inclined by 70 ° ± 15 °, it is also possible to add a slight elevation angle to the reversing sheet feeding table 64, so that the sheet feeding path is extremely gentle and the sheet feeding operation is smooth. And it will be performed reliably.

Even if the reversing sheet feeding table 64 is given an elevation angle of about 15 °, no problem occurs in the reversing sheet feeding operation. Therefore, the angle of the manual sheet feeding with respect to the conveying surface of the intermediate transfer belt 14a is further increased. As a result, the feeding operation of the transfer material by manual feeding is performed more smoothly and accurately.

[0043]

According to the present invention, the manual paper feeder is incorporated in a compact double-sided image forming apparatus having a small installation space according to the first and fifth aspects. By means of (7) and (7), the feeding path of the transfer material is formed as a gentle path that is easy to transport, and the thick transfer material is also transported to form a double-sided image.

Further, the transfer material after the image is transferred is fixed without impairing the image quality and paper quality according to claim 3 or 8,
Even if a transport trouble occurs, the processing is quickly and easily performed according to claim 4 or 9, and as a result, a practically useful double-sided image forming apparatus suitable for functions and various maintenances is provided. Was.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a double-sided image forming apparatus according to a first embodiment.

FIG. 2 is an explanatory view of a main part of the double-sided image forming apparatus according to the first embodiment;

FIG. 3 is a cross-sectional configuration diagram of a double-sided image forming apparatus according to a second embodiment.

FIG. 4 is an explanatory view of a main part of a double-sided image forming apparatus according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor drum 11 charger 12 laser writing device 13 developing device 14a intermediate transfer belt 14b transfer area 14c (first) transfer device 14f, 14h paper separator 14g (second) transfer device 15 paper cassette 16 carry-out roller 17, 17A Timing roller 19, 119 Cleaning device 20 Fixing device 20A, 20B Heat roller 30 Guide means 31 Spur 32 Propeller fan 40 Side door 51 Release lever 54 Locking lever 60, 60A Manual paper feed unit 61, 61A Paper feed table 62, 62A , 62B Paper feed roller 64 Reverse paper feed table S, SA, SB Photo sensor P Recording paper

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B65H 5/22 B65H 5/22 C 3F063 5/38 5/38 3F101 11/00 11/00 J 3F343 G03G 15/16 G03G 15/16 (72) Inventor Tetsu Haneda 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H028 BA06 BA16 BC00 2H032 AA02 BA09 BA15 BA23 2H071 BA04 BA14 BA15 BA27 BA29 DA09 DA15 DA23 2H072 AB07 CA03 CA07 CB08 HB08 JA02 3F049 AA10 CA02 CA03 LA01 LB03 3F063 AA01 AB01 AC03 AD03 AD06 BA10 CA01 CC03 CD05 3F101 FB05 FB07 FC04 FC11 LA01 LB03 3F343 FA02 FB01 GA01 GB01 GC01 GD01 HB02 HB03

Claims (9)

[Claims] 1. A double-sided image forming apparatus for transferring and fixing a toner image formed on an image forming body to both front and back surfaces of a transfer material via an intermediate transfer belt, wherein the transfer material is provided substantially horizontally. In the process of being carried out of the cassette and being conveyed upward by the intermediate transfer belt, toner images are formed on both front and back sides, and the paper is inverted and discharged in a substantially horizontal direction. A two-sided image forming apparatus, wherein a sheet is fed to the intermediate transfer belt from a substantially horizontal manual sheet feeding unit provided at an upper portion of a sheet feeding cassette. 2. The double-sided image forming apparatus according to claim 1, wherein the intermediate transfer belt has a transfer material conveying surface forming an elevation angle of 70 ° ± 15 ° with respect to a horizontal direction. 3. A double-sided image forming apparatus according to claim 1, wherein a transfer material guide means comprising a spur and an air flow is provided between said intermediate transfer belt and said fixing means. apparatus. 4. The double-sided image forming apparatus according to claim 1, wherein the intermediate transfer belt can be moved and retracted from the image forming body. 5. In a double-sided image forming apparatus for transferring and fixing a toner image formed on an image forming body to both front and back surfaces of a transfer material via an intermediate transfer belt, the transfer material is provided substantially horizontally. In the process of being carried out of the cassette and being conveyed upward by the intermediate transfer belt, toner images are formed on both front and back sides, and the paper is inverted in a substantially horizontal direction and discharged. A two-sided image forming apparatus, wherein the sheet is conveyed into the apparatus from a manual sheet feeding unit provided opposite to a sheet feeding cassette, and fed to the intermediate transfer belt via a reversing sheet feeding unit. 6. The double-sided image forming apparatus according to claim 5, wherein the transfer material conveying surface of the intermediate transfer belt forms an elevation angle of 70 ° ± 15 ° with respect to a horizontal direction. 7. The double-sided image forming apparatus according to claim 5, wherein the reversing sheet feeding section has a transfer material conveying surface forming an elevation angle of 15 ° ± 10 ° with respect to a horizontal direction. 8. A transfer material guide means comprising a spur and an air flow is provided between the intermediate transfer belt and the fixing means.
Item 2. The double-sided image forming apparatus according to Item 1. 9. The double-sided image forming apparatus according to claim 5, wherein the intermediate transfer belt is movable and retractable from the image forming body.