JPS60101576A - image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus such as an electrophotographic copying machine.

[Prior art]

Conventionally, there are two types of electrophotographic copying machines: continuous process type and two-rotation, one-copy type.

A continuous process type electrophotographic copying machine has a configuration as shown in FIG. 1, in which a charging device 2. Exposure device 3. Developing device 4° Transfer device 5. A cleaning device 6 and a static eliminator 7 are arranged in sequence, and a fixing device 9 is further provided.

In such a configuration, as the photoreceptor 1 rotates, the charging device 2 uniformly charges the surface of the photoreceptor 1,
Further, an exposure device 3 irradiates a light image of the original to form an electrostatic latent image corresponding to the original on the surface of the photoreceptor 1. Subsequently, the electrostatic latent image is visualized by the developing device 4. Photoreceptor 1 rotates further.

The visible image on the photoreceptor 1 is transferred to the cassette/nod 8 by the transfer device 5.
The image is transferred onto the transfer paper fed from the source. After the transfer, the transfer paper is separated from the photoreceptor 1, and after the image is fixed by the fixing device 9, it is discharged outside the machine.

Furthermore, after the transfer, the 1-ner and charges remaining on the photoreceptor 1 are processed by a cleaning device 6 and a static eliminator 7 in preparation for starting a new process.

In this way, the continuous copying type electrophotographic copying machine performs charging, exposure, and development while the photoreceptor 1 rotates once.

Transfer, fixing, static elimination and cleaning processes are applied.

A series of copy operations are being performed. Therefore, the photoreceptor can be made smaller in diameter.

On the other hand, a two-rotation, single-copy type electrophotographic copying machine has a configuration as shown in FIG. 2, in which a charging device 11. Exposure device 12, developing/cleaning device 13. A transfer device 14 and a static eliminator 15 are arranged in this order, and a fixing device 17 is further provided. The major difference in construction from the continuous process system shown in FIG. 1 is that an independent cleaning device is not provided, and the developing device also serves as a cleaning device.

In such a configuration, as the photoreceptor IO rotates,
First, the charging device 11 uniformly charges the surface of the photoreceptor 10, and the exposure device 12 irradiates a light image of the document to form an electrostatic latent image corresponding to the document on the surface of the photoreceptor 10. Subsequently, the electrostatic latent image is visualized by the developing/cleaning device 13. Further, the visible image on the photoreceptor IO is transferred by the transfer device 14 onto transfer paper fed from the cassette 16. After the transfer, the transfer paper is separated from the photoreceptor 10, and the image is further fixed by a fixing device 17, and then discharged outside the machine. Also, after transcription.

The photoreceptor 10 continues to rotate further and enters the second rotation.

The developing/cleaning device 13 and the static eliminator 15 perform static neutralization and cleaning to prepare for the start of a new process.

In this way, a two-rotation, one-copy type electrophotographic copying machine performs charging, exposure, and development during the first rotation of the photoreceptor lO.

In the second rotation, charge removal and cleaning are performed, and one copying operation is completed in two rotations of the photoreceptor 10.

[Problems with conventional technology]

In the above-mentioned continuous process type electrophotographic copying machine,
Since the cleaning device is provided independently of the developing device, the cost is high, and both devices take up a lot of space around the photoreceptor, which increases the restrictions on the structure of other parts. Also.

Toner scattering occurs from both devices, increasing the amount of dirt inside the machine. Furthermore, if the toner that has been cleaned and removed by the cleaning device is thrown away, the amount of toner consumed will increase, making it uneconomical. On the other hand, an expensive toner conveying device is required to collect the cleaned and removed toner and return it to the developing device. Therefore, it is not appropriate in any case.

On the other hand, in a two-rotation, one-copy type electrophotographic copying machine, an image corresponding to the length of the document must be formed on the photoreceptor without overlapping in the first rotation of the photoreceptor. For this reason,
The circumference of the photoconductor must be long enough to accommodate the maximum length of the original that can be copied → -1 For example, when the maximum original is 84 plates, the length is 364 mm, so the photoconductor The circumferential length of the photoreceptor is 364 mm plus an allowance, and a photoreceptor with a diameter of approximately 120 ntm is required. in this way.

For example, compared to a continuous process method, a large 4-tooth photoreceptor is required, which is disadvantageous in terms of the space for the 8-photoreceptor and the surface of the photoreceptor. In addition, when the transfer paper is small compared to the original size or when the platen cover is opened to copy a thick original, there is a so-called untransferred area on the photoconductor where the toner on the photoconductor is not transferred at all to the transfer paper. However, since the 2-rotation, 1-copy, 1-copy system does not have a dedicated cleaning device, the cleaning ability is not sufficient, and therefore, the toner in the untransferred area remains without being sufficiently cleaned, and this is transferred onto the next transfer paper. Put it away. As a means to prevent this problem, the cleaning process has been repeated multiple times for each copy, but this inevitably reduces the copying speed.

[Purpose of the invention]

In view of the above-mentioned conventional drawbacks, the present invention has a high cleaning ability and can obtain high-quality images.

Another object of the present invention is to provide an image forming apparatus that can be made smaller in size.

[Key points of the invention]

In order to achieve the above object, the present invention uses a bristle brush as a transfer device in a transfer type image forming apparatus using an image carrier, and the bristle brush also serves as a cleaning device for toner on the image carrier. Features [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a block diagram of an image forming apparatus showing an embodiment of the present invention, and FIG. 4 is a block diagram of a transfer device.

In FIG. 3, a charging device 19. Developing and cleaning device 20, transfer device 2
1. Separation device 26. Eraser lamps 22 and 1-ner disturbance parts 23 are arranged in sequence.

Furthermore, exposure device 24. A fixing device 27 is provided respectively.

The photoreceptor 18 is provided in the shape of a tram that can be rotated in the direction of the arrow shown in the figure, and its surface is made of a photoconductive material such as Se or ZnO2 organic photoconductor 44.

Further, the circumferential length of the photoreceptor 18 is shorter than the maximum original size for image formation, and the maximum original size is A4.
In this case, for example, one having a diameter of about 50 ffl Tn is used.

The charging device 19 is a corona discharger for uniformly charging the surface of the photoreceptor 18 to a predetermined polarity.

The developing/cleaning device 20 is configured to perform both development and cleaning, and the developer is attached to the surface of the sleeve 208 and rubbed on the surface of the photoreceptor 18. As the developer, for example, a one-component magnetic toner having relatively low resistance is used.

The transfer device 21 includes a bristle brush 37, a bias roll 38, and a scraper 39 in a casing 36 (see FIG. 4). The bristle brush 70 37 is a conductive bristle brush having a resistivity of about 10 Ω·cm, and is used to rub the surface of the photoreceptor 18.

The sliding portion rotates in the same direction as the photoreceptor 18 . Further, a bias roll 38 is provided in contact with the bristle brush 37 and is rotatable in the direction of the arrow, and a scraper 39 is provided with one end in contact with the bias roll 38. A bias voltage I having the same polarity as the charged polarity of the photoreceptor 18 is applied to the bristle brush 37 by a power source 40, and the bias voltage
Similarly, a bias voltage V2 is applied by the power supply 41 to the bias voltage V2, and the voltage value is set to 'J2>V+.

For example, when Se is used as the photoreceptor 18, the polarity is positive, ζV+-+80QV, V2=+l 000
V is applied respectively.

The eraser lamp 22 is a light source for optically eliminating residual charges on the photoreceptor 18.

The l.ner disturbance part 23 is a rotatable insulating bristle brush, and is provided so as to rub the surface of the photoreceptor 18.

The exposure device 24 includes a light source 25. It consists of a lens and multiple mirrors.

Further, originals used for forming one image are inserted from six directions at the top of the main body of the apparatus, and are sent onto the original glass table 28 at a direction of original feed 1: J-ra 29°30.

On the other hand, paper feeding is performed by a manual feeding method, and the transfer paper is sequentially inserted in the direction B from the manual feed table 31.

The operation of the image forming apparatus having the above configuration will be described next.

When a print button (not shown) is turned on, each device starts operating and the photoreceptor 18 starts rotating in the direction of the arrow. As the photoreceptor 18 rotates, first.

The surface of the photoreceptor 18 is uniformly charged to a predetermined polarity by the charging device 19 . Next, the exposure device 24 exposes the original image. That is, the light source 25 illuminates the original on the original glass table 28 that has been fed by the original feed rollers 29 and 30, and the reflected light is directed to the photoreceptor 1 through the lens and mirror.
8. Project onto the surface. This exposure forms an electrostatic latent image corresponding to the original on the surface of the photoreceptor 18.

This formed electrostatic latent image is visualized by toner in the next developing/cleaning device 20. In other words, the developer deposited on the sleeve 20a is rubbed and the 1-ner, which has a polarity opposite to that of the surface of the photoreceptor 18, is attracted to the electrostatic latent image.

On the other hand, the transfer paper inserted from the manual feed stand 31 is transferred to the paper feed roller 3.
2, it is sent to the position of the registration roller 33, and is sent to the transfer section by the registration roller 33 in synchronization with the visible image on the photoreceptor 18. In the transfer device 21, a voltage with a polarity opposite to that of 1 to toner on the photoconductor 18 (that is, the same polarity as the photoconductor 18) is applied through a bristle brush 37 rotating from the back side of the transfer paper, and the toner on the photoconductor 18 is transferred onto the transfer paper. transcribed into. Here, when the transfer paper is small compared to the original size, a portion where the toner on the photoreceptor 18 is not transferred to the transfer paper at all, a so-called untransferred portion, is generated on the photoreceptor 18. The toner is directly rubbed by the bristle brush 37.

Due to the sliding force of the bristle brush 37 and the electric effect caused by the applied bias voltage, the toner in the untransferred area is removed by the bristle brush 37.
7 and is completely cleaned. Furthermore, the toner 42 adsorbed by the bristle brush 37 is transferred to the bias roll 38.
and is scraped off by the scraper 39. The bristle brush 37 can be used again after the absorbed toner 42 is completely removed. Therefore, in the transfer device 21, the toner is directly transferred from the image area on the photoreceptor 18 onto the transfer paper, and if toner exists in the untransferred area, it is completely cleaned and the toner in the untransferred area 91 disappears.

Thereafter, the transfer paper is separated from the photoreceptor 18 by the separation device 2G, sent by the feed roller 34, and after the image is fixed by the fixing device 27, it is ejected from the paper discharge roller 35 to the outside of the machine.

After the transfer process, the normal two-rotation-one-copy system enters a cleaning process, in which the photoreceptor is neutralized and residual toner is collected by a developing and cleaning device. However, in this image forming apparatus, the circumferential length of the photoreceptor 18 is shorter than the maximum original size. In other words, after the transfer process of the portion corresponding to the leading edge of the maximum size document is completed, the photoreceptor 18 then enters a static elimination process, in which the electrostatic latent image remaining on the surface of the photoreceptor 18 is removed by the eraser lamp 22. The corresponding charge is erased.The transfer efficiency in the above transfer process is not 100%, so naturally the residual toner remains formed on the photoreceptor 18, but after the above charge removal process is completed, this residual toner is removed. The photoreceptor 18 is
The top is almost uniformly disturbed. This toner disturbing member 23 does not have the ability to clean the residual toner and merely disturbs the residual toner onto the photoreceptor 1B. In this embodiment, the toner disturbance member 23 is an insulating bristle brush, preferably a member that is charged with the same polarity as the toner charge polarity. The effect can be fully obtained.

After passing through the toner disturbance section JfA23, the photoconductor I8 is charged again by the charging device 19, and then the exposure process for the first continuous sheet is continued by the exposure device 24.
A new electrostatic latent image is formed on the 8 surface. At this time, residual 1
- The toner is uniformly and thinly dispersed on the photoreceptor 18, so it does not interfere with the formation of an electrostatic latent image.

The new electrostatic latent image formed in the area where the photoreceptor 18 rotates more than once is visualized in the next developing/cleaning device 20 and transferred onto transfer paper in the subsequent transfer step. At this time, some of the residual 1-toner dispersed on the photoreceptor 1B is cleaned by the developing/cleaning device 20, and some proceeds to the transfer process, but this residual toner is an extremely thin layer and Since the toner itself has a relatively low resistance, it does not have enough polarity to be transferred in the transfer process, so there is no problem of it appearing on the transfer paper.

In this way, after one sheet of image formation is completed in the image forming process of more than one revolution of the photoreceptor 18, one of the photoreceptors 18 is There is a post-processing process specifically for cleaning the rotation. In other words, in this dedicated cleaning process, the transfer device 21
．． Eraser lamp 22. Toner disturbance member 23. The developing/cleaning device 20 completely erases residual toner and residual charges on the photoreceptor 18. At this time, the transfer device 21
Since the bristle brush 37 directly rubs the surface of the photoreceptor 18 and is used as a cleaning bristle brush, the cleaning ability is greatly improved, and one cleaning step is sufficient. Further, as described above, since the toner in the untransferred area is cleaned at the same time as the transfer, the fact that there is no toner in the untransferred area further improves the stability of cleaning.

When this cleaning-only post-processing step is completed, a new image forming step is started, and the above-described steps are repeated again.

Incidentally, the present invention is not limited to this embodiment, and a bristle brush can be used as the transfer device in a normal transfer type image forming apparatus.

〔Effect of the invention〕

As explained in detail above, the image forming apparatus of the present invention uses a bristle brush as a transfer device and also serves as a cleaning device, so it has a high cleaning ability and can produce high quality images. It is also possible to downsize the machine itself.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional continuous process type electrophotographic copying machine, Fig. 2 is a block diagram of a conventional 2-rotation, 1-copy type electrophotographic copying machine, and Fig. 3 is a block diagram of an embodiment of the present invention. FIG. 4 is a block diagram of the image forming apparatus shown in FIG. 4, and FIG. 4 is a block diagram of the transfer device. 1.10.18...Photoreceptor, 2,11°19...
Charging device, 3,12.24... Exposure device, 4...
・Developing device. 5.14.21... Transfer device, 6... Cleaning device, 7.15... Static eliminator, 9,17.27
...Fixing device. 13.20...Developing and cleaning device. 22... Eraser lamp 5 23... L-ner disturbance member, 26... Separation device. 28... Original glass stand, 31... Manual feed stand, 3
2... Paper feed roller, 33... Registration roller, 3
7...Hair brush. 38...Bias roll, 39...Scretsma patent applicant Casio Computer Co., Ltd. Same as above Yoshiyuki Osuga, agent patent attorney for ID Co., Ltd.

Claims (2)

[Claims] (1) An image forming apparatus of a transfer type using an image carrier, characterized in that a bristle brush is used as the transfer device, and the bristle brush also serves as a cleaning device for toner on the image carrier. . (2) The image forming apparatus according to claim 1, wherein the bristle brush is electrically conductive.