JPH0517653U - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents slippage between the film and the photoconductor and enables good image formation without image distortion or image blur. [Structure] The support shaft 12 is provided at a position upstream of the developing device 106.
6 is rotatably attached and biasing means 127
By providing a pinch roller 125 which is brought into pressure contact with the photosensitive member 101 from above the developing member 102, and by enhancing the frictional force due to the contact pressure between the two, the peripheral speed of the photosensitive member and the moving speed of the developing member are completely eliminated. Can be matched to prevent slipping.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image forming apparatus used in a copying machine, a printer, a facsimile or the like. More specifically, the present invention relates to an image forming apparatus for developing a latent image bearing member on which a latent image is formed so as to correspond to the latent image on a development target.

[0002]

[Prior Art]

 Conventionally, as an image forming apparatus used in a printer or a copying machine, an electrophotographic recording method based on the Carlson method is generally widely used due to its features such as high recording speed, high image quality, and recording on plain paper. ..

As is well known, this method was roughly composed of the following six basic processes. That is, the latent image carrier is subjected to charging, exposure and development processes to form a toner image on the latent image carrier. Then, the toner image on the latent image carrier is superposed on a recording carrier typified by paper and transferred. Then, the toner image on the recording support is fixed on the recording support. On the other hand, since the latent image carrier is repeatedly used, the residual toner after transfer is cleaned by the cleaning device.

In the transfer process in the apparatus having this configuration, a method using electrostatic force is generally used. However, since this method has poor transfer efficiency, a cleaning process for cleaning the residual toner on the latent image carrier after transfer is indispensable. Therefore, maintenance work is required to discard the collected residual toner. At this time, since the residual toner is powder, it easily scatters, which causes problems such as contaminating the operator's body and clothing, and scattering inside and outside the apparatus.

In order to solve these problems, a recording method that does not require a cleaning process and discards residual toner is proposed in Document 1: Japanese Patent Application No. 01-212976. In this method, as shown in FIG. 4, the photosensitive member 11 and the developed member 14 (hereinafter also referred to as a film) are provided so as to partially adhere to each other, and the photosensitive member is uniformly charged. (Corona discharger 15), exposure means 16 for forming an electrostatic latent image, developing device 17 for forming a toner image on a developing object that is in close contact with the photoconductor on which the electrostatic latent image is formed, and developing object The recording medium is superposed on the toner image on the body, and means for transferring the toner image to the recording medium (pressurizing roll 13, heat-generating roll 12) is provided.

In the transfer process, the toner image on the development target is transferred onto the recording support by heating and pressing. In this case, even if the toner image remains on the developed material after transfer, it can be easily wiped off with a pad 23 such as felt while the toner is melted immediately after transfer. At this time, since the toner has changed from powder to semi-liquid property, it does not scatter. Alternatively, if the surface of the developed material is coated with a material having a good releasability, such as a fluorine resin, the toner remaining on the film after the transfer can be extremely reduced, and an afterimage will be generated during the next recording. It never happens. Therefore, the conventional cleaning process becomes unnecessary. In addition, the toner can be fixed on the recording paper at the same time as the transfer, which eliminates the need for an independent fixing device, further reducing the number of processes. Therefore, conventionally, it is possible to remove the scattering and contamination of the toner on the body and clothes of the operator, the inside of the apparatus, and the surroundings of the apparatus, which occurred during the operation of discarding the residual toner, so that the maintainability can be improved. Moreover, since it is possible to reduce the number of processes, it is an excellent device that can be downsized and cost-effective.

[0007]

[Problems to be solved by the device]

 However, in the conventional apparatus, image distortion or image blur may occur in the sheet feeding direction of the recording support. When investigating the cause of this, it was found that distortion of this image occurred on the developed object. Therefore, it can be seen that this cause is not caused by the transfer process but by the process before that, that is, the exposure process or the development process which is a latent image forming means.

In order to investigate which of these two processes is the cause, the film was removed from the apparatus, and when direct development was carried out on the photoconductor on which the electrostatic latent image was formed, it was developed on the photoconductor. It was found that the image was not distorted, that is, the cause of the image distortion was not the exposure process.

Judging from the above, it can be concluded that the place where the image distortion in the sheet feeding direction occurs in the conventional apparatus is the developing process, and the developing method is performed on the developed object superposed on the photoconductor. It turns out to be a problem peculiar to. In other words, it is considered that the photoconductor and the film slip, and the electrostatic latent image formed on the photoconductor cannot be developed on the film to have a size of 1: 1 with respect to the electrostatic latent image formed on the photoconductor.

In the conventional apparatus, the film is moved together with the photoconductor by the frictional force between the film and the photoconductor that is rotated by a driving unit (not shown). However, although the photoconductor and the film were in contact with each other over a wide area, the friction coefficient between them was not large. In addition, the contact pressure depends on the tension (tensile force) of the film, and considering the tensile strength of the film, this tension could not be increased. For this reason, a large force cannot be obtained as a frictional force between the photoconductor and the film, and a slight slippage occurs. Therefore, it is difficult to remove the image distortion or the image blur with the conventional device. ..

The object of the present invention is to prevent the movement of the film, which is the development target, and the photoconductor from slipping, so that development can be performed on the film in conformity with the electrostatic latent image on the photoconductor. An object of the present invention is to provide an excellent apparatus capable of obtaining a good image without image distortion or image blur.

[0012]

[Means for Solving the Problems]

 The present invention comprises a latent image bearing member, a development target which is stretched between the latent image bearing member and another roller and a portion of which is closely adhered to the latent image bearing member and a latent image bearing member on the surface of the latent image bearing member. In an image forming apparatus provided with a means for forming an image and a developing means for forming a toner image on the object to be developed, which is closely adhered to the surface of the latent image carrier, a latent image is formed upstream of the developing means. A roller is provided in pressure contact with a development target that is superposed on an image bearing member.

[0013]

[Action]

 According to the present invention, the object to be developed is strongly pressed against the photoconductor by the pinch roller provided between the photoconductor and the film at the position upstream of the developing device. The contact pressure of becomes very strong and a strong frictional force acts between them. Therefore, the movement of the film is strongly restricted by the photoconductor, and the peripheral speed of the photoconductor and the moving speed of the film are completely the same, and the film moves without slippage. Therefore, it becomes possible to develop a good visible image without image distortion or blurring, which is exactly the same as the latent image on the photoconductor, on the film, and the above object can be achieved.

[0014]

【Example】

 First, the configuration of the recording apparatus of the present invention will be described with reference to FIG.

The photosensitive member 101 as a latent image carrier formed in a drum shape is one in which a photoconductive layer 101b is provided on a conductive support 101a, and is composed of a selenium photosensitive member, an organic photosensitive member, and a zinc oxide photosensitive member. Both a body and an amorphous silicon photoconductor can be used. The developing object 102 is stretched around the photoconductor 101, the heating roller 113 as one transfer means, the rolling roller 103, and the pulling roller 111.

As will be described later, the developed object 102 is heated in the transfer process and reaches around 160 ° C. Therefore, it is necessary to consider the heat resistance of the material. Also, some insulation is required. Taking these into consideration, a film using a material such as polyester, polyimide, polyetherimide, polyethersulfone, polyetheretherketone, or polyphenylene sulfide can be used as the film base material. In consideration of the lines of electric force generated between the developed material and the toner carrying member during development, the film thickness is preferably 100 μm or less, and the tensile strength and handleability are preferably 5 μm or more. In this embodiment, a polyimide base material is coated with a fluorine resin having excellent releasability.

The charging device 104 as a charging unit is provided so as to face the surface of the latent image carrier. A corona discharger as shown in the figure is provided as the charging device. In addition to this, for example, a charging roller in which a metallic cored bar is coated with a conductive rubber can be used.

The exposure device 105 as an exposure unit converts an image signal into light and irradiates the photoconductor with it. As the exposure apparatus, a combination of a light source such as a laser or an LED array and an image forming optical system, or an optical system for projecting reflected light of an original, which is generally used as a copying machine, can be used.

The developing device 106 as a developing unit adsorbs the toner 108 on the toner carrier 107 and conveys the toner 108 in the direction of the arrow shown in the drawing, and the electrostatic latent image formed on the photoconductor is closely contacted and overlapped. The developed object 102 is developed. As the developing device, a known technique such as a two-component magnetic brush image developing device and a one-component non-magnetic developing device can be used.

As a transfer device as a transfer device, one transfer device 113 and the other transfer device 140 are pressed at a constant pressure by a pressurizing device (not shown). In this embodiment, the one transfer means 113 is a heating roller, and is a metal hollow member having a halogen lamp built therein. In addition to this, a heating resistance layer made of Ni-P or the like is formed on the surface of a base material such as glass or ceramic, and a protective layer such as Ta ₂ O ₅ or fluorine resin is further formed thereon. You may. Further, it is also possible to use a strip-shaped form instead of the roller-shaped form. The other transfer means 140 is composed of an elastic pressure roller. This roll is made by laminating rubber on a metallic cored bar, and silicon rubber or the like is preferable as the rubber.

Next, the operation and action of this recording apparatus will be described.

The photosensitive member 101 is rotated at a constant peripheral speed in the direction of the arrow shown by the driving means (not shown). The object to be developed is strongly pressed against the photoconductor by a pinch roller 125 provided between the photoconductor and the film at a position upstream of the developing device 106, and friction with the photoconductor based on the contact pressure. Move by force. The pinch roller 125 is preferably a metal cored bar laminated with an elastic material such as rubber. The pinch roller 125 is configured to be rotatable with respect to the support shaft 126, and is pinched between the films and strongly pressed against the photoconductor 101 by the urging means 127. Therefore, the contact pressure between the film and the photoconductor becomes very strong, and a strong frictional force acts between them. Therefore, the movement of the film is strongly restrained by the photoconductor, and the peripheral speed of the photoconductor and the moving speed of the film move in the direction of the arrow shown in the figure without any slippage.

The pressure contact position of the pinch roller is considered in the range where the photoconductor and the film come into contact with each other. However, since the toner is developed on the film in the downstream of the developing device, there is a risk that the pressure of the pinch roller will contaminate the toner image. There is. Therefore, in this embodiment, the pressure contact position of the pinch roller is set on the upstream side of the developing device. In this case, the electrostatic latent image is formed on the photoconductor, but since the electrostatic latent image is in contact with the photoconductor through the insulating film, the electrostatic latent image is not destroyed.

The image forming method will be described below.

First, the charging device is operated to uniformly and uniformly charge the photoconductor 101 (101a is a conductive support, 101b is a photoconductive layer). Next, the exposure device 105 irradiates the latent image carrier with light corresponding to the image signal, and an electrostatic latent image is formed.

In the developing process (see FIG. 2), the developing device 106 is provided in contact with or in close proximity to the object to be developed 102 that is in close contact with the photoreceptor 101. In this embodiment, reversal development is performed, and a bias voltage applying unit 109 is provided between the conductive support 101a of the photoconductor and the toner carrier 107 so that a bias voltage is applied. With such a structure, electric lines of force associated with the electrostatic latent image formed on the photoconductor are generated in the space between the toner carrier and the development target through the development target. For this reason, the charged toner 108 on the toner carrier adheres to the object to be developed by electrostatic force and is developed. Here, since the photoconductor on which the electrostatic latent image has already been formed and the film overlaid on it move at the same speed, there is no distortion in the moving direction on the film, and there is no image blurring. It is developed into a 1: 1 visible image with the latent image.

On the other hand, the recording support (recording paper) 114 accommodated in the recording paper cassette 120 is fed by a paper feed roll 115 and sent to a transfer device by a paper feed roll 116.

In the transfer process (see FIG. 3), the recording support 114 is superposed on the development target 102 on which the toner image is formed, is sandwiched between the heating roller 113 and the pressure roller 140, and is pressed against it by means not shown. .. The toner on the development target 102 is heated and melted by the heat from the heating roller 113 being transferred to the toner through the development target, and the melted toner is transferred from the development target to the recording support 114 and fixed at the same time. It After that, the recording support is discharged to a stacker (not shown) outside the apparatus.

After the transfer, the toner hardly remains on the developed object due to the releasing property of the fluorine resin coated on the surface thereof. Therefore, the afterimage does not occur on the recording paper at the next image formation.

On the other hand, after the completion of the development process, the photoconductor may be provided with a discharge lamp 118 or the like as necessary to irradiate the entire surface with light to remove the residual charges on the photoconductor. Even in this way, the photoconductor is repeatedly used.

In this embodiment, the photoconductor is used as the latent image carrier and the electrostatic latent image is used as the latent image, but the latent image carrier is not limited to this. Further, although the method of transferring onto recording paper after development has been described, the invention is not limited to this.

[0032]

[Effect of the device]

 As described above, according to the present invention, since the moving speed of the photoconductor and the moving speed of the film can be perfectly matched, the electrostatic latent image formed on the photoconductor can be exactly the same. A visual image can be formed on the film. That is, it is possible to form a good visible image without distortion in the moving direction of the film and without blurring. Further, since the pinch roller is provided upstream of the developing device, the developed toner image on the film is not deteriorated.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing a developing process.

FIG. 3 is a diagram showing a transfer process.

FIG. 4 is a schematic configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

 101 Latent Image Carrier 102 Developing Object 103 Rolling Roll 104 Charging Device 105 Exposure Device 106 Developing Device 107 Toner Carrier 108 Toner 109 Bias Voltage Applying Means 111 Pulling Roll 113 Heating Roller 114 Recording Paper 115 Paper Feeding Roll 116 Paper Feeding Roll 117 paper discharge roll 118 static elimination lamp 120 recording paper cassette 125 pinch roller 126 support shaft 127 urging means 140 pressure roller

Claims (1)

[Scope of utility model registration request] 1. A latent image bearing member, an object to be developed which is stretched between the latent image bearing member and another roller and a part of which is closely adhered to the latent image bearing member, and the surface of the latent image bearing member. An image forming apparatus provided with a means for forming a latent image and a developing means for forming a toner image on the developed object, which is closely adhered to the surface of the latent image carrier, and is provided upstream of the developing means. An image forming apparatus characterized in that a roller is provided in pressure contact with a development target which is superposed on the latent image carrier.