JPS60107054A - Image forming device - Google Patents

Abstract

PURPOSE:To make a machine small-sized, to obtain it at a low cost, and to obtain a picture of high quality by stirring a residual toner of the first rotation of a drum so as to become a thin layer by a stirring means, in a transfer type electrophotography copying machine for using a developing device as a cleaner, too. CONSTITUTION:As for a small-sized drum 18, its circumferential length is shorter than transfe paper, therefore, unless it executes two rotations, an image formation (electrification, image exposure, development and transfer) is not completed. A toner stirring brush 23 has the same electrified polarity as a toner, therefore, a residual toner of the first rotation does not adhere. The residual toner is stirred and becomes a thin layer, therefore, it exerts no influence on an image exposure of the second rotation. The photosensitive surface is cleaned by a development and cleaning combining means 20 at the time of the third and the fourth rotations, and the residual toner is removed.

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 first 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. The photoreceptor 1 further rotates, and the visible image on the photoreceptor 1 is transferred by the transfer device 5 onto transfer paper fed from the cassette 8. After the transfer, the transfer paper is separated from the photoreceptor 1 and then transferred to the fixing device 9.
After the image is fixed, it is ejected outside the machine.

Further, after the transfer, toner 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, a continuous process type electrophotographic copying machine performs charging, exposure, and development while each photoreceptor rotates.

Performs transfer, fixing, static neutralization and cleaning processes.

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

On the other hand, a 2-rotation, 1-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 10 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 a developing/cleaning device 13. Further, the visible image on the photoreceptor lo is transferred by a transfer device 14 onto transfer paper fed from a cassette 16. After the transfer, the transfer paper is separated from the photoreceptor 10, and the image is further fixed in the fixing device 17.
It is ejected from the aircraft. 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, in a two-rotation, one-copy type electrophotographic copying machine, the photoreceptor is charged, exposed, and developed at the 1001st rotation.

During the second rotation of the transfer, charge removal and cleaning are performed, and one copying operation is completed with two rotations of the photoreceptor 1o.

[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 the cleaning device takes 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 circumferential length of the photoreceptor must be equal to the maximum length of the original that can be copied.1For example, if the maximum original is 84mm
When it is a plate, the length is 364 + n, so the circumference of the photoreceptor requires 364 + extra length, and the diameter is about 1
A 20 m photoreceptor is required. In this way, compared to, for example, a continuous process method, a larger photoreceptor is required, which is disadvantageous in terms of photoreceptor space and cost. I can't do that.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional art, it is an object of the present invention to provide an image forming apparatus that can reduce the size and cost of a nine-mechanical die and that can obtain high-quality images.

[Key points of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus that serves both as a developing device and a cleaning device, in which at least a transfer device, a static eliminator, and a charging device are disposed around an image carrier, and a toner disturbance member is disposed downstream of the transfer device. The charging device is characterized in that the charging device is disposed on the upstream side of the charging device.

[Embodiments of the invention] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram of an image forming apparatus showing an embodiment of the present invention.

In FIG. 3, a charging device 19 is located around the photoreceptor, which is an image carrier. Developing and cleaning device 20, transfer device 2
11 Separation device 26. Eraser lamp 22. Toner disrupting members 23 are sequentially arranged.

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

The photoreceptor 18 is provided in the shape of a drum that can rotate in the direction of the arrow shown in the figure, and its surface is Ss, 2! : It is made of a photoconductive material such as nO1 organic photoconductive material.

Further, the circumferential length of the photoreceptor 18 is shorter than the transfer paper size on which the image is formed, and this transfer paper size is A4.
In this case, for example, one having a diameter of about 50w5 is used. This circumference is approximately half the circumference of a photoreceptor used in a normal two-rotation, one-copy copying machine.

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

The developing and cleaning device 20 is configured to perform both development and cleaning, and the developer is attached to the surface of the sleeve 20a and rubbed against 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 is a corona discharger that charges the back surface of the transfer paper with a charge having a polarity opposite to that of the toner of the developer used.

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

The toner disturbance member 23 is a rotatable insulating bristle brush made of a material such as nylon, and is provided so as to rub the surface of the photoreceptor 18 .

The exposure device 24 includes a light source 24a, a lens 24b, and a plurality of mirrors 24c, 24d, and '24e.

The separating device 26 is configured by a well-known separation belt system, for example, and the fixing device 27 is configured by a pair of hot rollers that press and rotate.

On the other hand, the original to be used for forming two images is inserted from the upper part of the main body of the apparatus in the A direction, is sent toward the original glass table 28 by the original feed rollers 29 and 30, and is then ejected out of the machine by the original ejection roller 25. Ru.

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

The operation of the image forming apparatus with 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 24a irradiates the document on the document glass table 28 that has been sent by the document feed rollers 29, 30, and the reflected light is transmitted to the lens 24b, the mirror 24c, and the mirror 24c.
The image is projected onto the surface of the photoreceptor 18 via 24d and 24e.

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. Sleeve 2. The developer adhering to Oa rubs the toner, and the toner having the opposite polarity to 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 having a polarity opposite to that of the toner on the photoconductor 18 (that is, the same polarity as the photoconductor 18) is applied from the back side of the transfer paper, and the toner on the photoconductor 18 is transferred onto the transfer paper.

Thereafter, the transfer paper is separated from the photoreceptor 18 by a separation device 26, sent by a feed roller 34, and after the image is fixed by a fixing device 27, it is ejected from the machine by a paper ejection roller 35.

After the transfer process, in the normal two-rotation-one-copy system, a cleaning process begins, in which the photoreceptor is neutralized and residual toner is collected by a developing and cleaning device. However, in this image forming apparatus, the circumference of the photoreceptor 18 is shorter than the size of the transfer paper used.

For example, if an image is to be formed on a transfer paper that is longer than the circumference of the photoreceptor 18, an image forming step is performed continuously after the above-mentioned transfer step is completed. That is, after the transfer process of the portion corresponding to the leading edge of the document is completed, the photoconductor 18 subsequently enters a static elimination process, and the photoconductor 18 is erased by the eraser lamp 22.
The charge corresponding to the electrostatic latent image remaining on the surface is erased. Here, since the transfer efficiency in the transfer step is not 100%, the residual toner naturally remains formed on the photoreceptor 18, but after the static elimination step is completed, the residual toner is uniformly distributed on the photoreceptor 18 by the toner disturbance member 23. Disturbed. This toner agitating member 23 does not have the ability to clean the residual toner, but simply agitates the residual toner uniformly on the photoreceptor. In this embodiment, the toner disturbance member 23 is an insulating bristle brush, preferably a member charged to the same polarity as that of the toner, and is driven by the photoreceptor 18 or rotated at a low speed. The effect can be obtained.

After passing through the toner disturbance member 23, the photoreceptor 18 is charged to the charging device 1.
The photoconductor 18-
A new electrostatic latent image is formed on the surface. At this time, the residual toner is uniformly and thinly dispersed on the photoreceptor 18, so that it does not interfere with the formation of an electrostatic latent image.

The new electrostatic latent image formed in the area over one rotation of the photoreceptor 18 is made visible by the next developing/cleaning device 20, and is continuously transferred onto the transfer paper in the subsequent transfer process. At this time, some of the residual toner dispersed on the photoreceptor 18 is cleaned by the developing/cleaning device 20, and some of it proceeds to the transfer process, but this residual toner is an extremely thin layer and the toner itself is Since it 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 rotation of the photoreceptor 18, the photoreceptor 18 is rotated for one day in order to completely erase the toner and charge remaining on the photoreceptor 18. A post-processing process dedicated to cleaning is performed for more than one rotation. That is, in this cleaning-only process, the charging device 19. Exposure device 24. With the transfer device 21 inactive, the eraser lamp 22. Toner disturbance member 23. The developing/cleaning device 20 completely erases residual toner and residual charges on the photoreceptor 18. On this occasion.

The toner agitating member 23 rubs against the surface of the photoreceptor 18 to agitate residual toner, thereby contributing to improving the cleaning ability of the secondary developing/cleaning device 20 .

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

FIG. 4 is a configuration diagram of an image forming apparatus showing another embodiment of the present invention.

The difference in configuration from the embodiment shown in FIG. 3 is that the toner disturbance member 23 is provided downstream of the exposure device 24 and upstream of the developing/cleaning device 20; Therefore, in the 9th image forming process, when forming a new image in an area that exceeds one rotation of the photoreceptor 18,
In the embodiment shown in FIG. 3, a new electrostatic latent image is formed after the residual toner is disturbed by the toner disturbance member 23, whereas in the embodiment shown in FIG. The difference is that after erasing, a new electrostatic latent image is formed on the afterimage of the residual toner on the photoreceptor 18, and then the residual toner is disturbed by a toner disturbance member 23, but the other steps are different. In exactly the same way, the toner disturbing member 23 efficiently disturbs the residual toner even in the cleaning-only process, contributing to improving the cleaning ability. As described above, in the embodiments shown in FIGS. 3 and 4, although the arrangement of the toner disturbing member 23 is different, the purpose of uniformly disturbing the residual toner is the same. Furthermore, the toner disturbing member 23 of this embodiment does not necessarily have to be insulative and may be conductive. In addition, in the above embodiment.

Change the transfer paper size to A4. When the diameter of the photoreceptor 18 is 50 m or more, image formation is performed by approximately two rotations of the photoreceptor 18.
If this is done three times, it is possible to further reduce the diameter of the photoreceptor 18. Furthermore, it goes without saying that the developer used can be not only one-component but also two-component.

〔Effect of the invention〕

As explained in detail above, the image forming apparatus of the present invention is provided with a toner disturbance member that disturbs the residual toner, and uses a photoconductor having a circumference shorter than the size of the transfer paper, although it is a dual-use developing/cleaning device W. This makes it possible to reduce the size and cost of one machine itself, and to obtain even higher quality images.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional one-rotation, one-copy, one-way type electrophotographic copying machine, Fig. 2 is a block diagram of a conventional two-rotation, one-copy, one-way type electrophotographic copying machine, and Fig. 3 is a diagram of one of the present invention. FIG. 4 is a block diagram of an image forming apparatus showing another embodiment of the present invention. 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, 23... Toner disturbance member, 26... Separation device. 28... Original glass stand, 31... Manual feed stand, 3
2... Paper feed roller, 33... Registration roller patent applicant Casio Computer Co., Ltd. Same as above Yoshiyuki Osuga, agent patent attorney for ID Co., Ltd.

Claims (3)

[Claims] (1) In an image forming apparatus that includes a developing device and a cleaning device, at least a transfer device, a
An image forming apparatus characterized in that a static eliminator and a charging device are arranged, and a toner disturbance member is arranged downstream of the transfer device and upstream of the charging device. (2) The image forming apparatus according to claim 1, wherein the toner disturbing member is disposed downstream of the static eliminator and upstream of the charging device. (3) The image forming apparatus according to claim 1, wherein the toner disturbing member is a bristle brush.