JPS60136785A - Image forming device - Google Patents

Abstract

PURPOSE:To destaticizing a photosensitive body sufficiently without any influence of toner particles and improve cleaning effect by irradiating the photosensitive body with eraser light from the reverse surface side. CONSTITUTION:An eraser lamp 22 is provided in the photosensitive drum 18 formed of a transparent hollow drum 39, etc., at the upstream side of an electrifier 19 and at the downstream side of a transfer device 21. The drum 18 is irradiated by this lamp 22 from the reverse surface side to destaticize residual charges from the drum 18 sufficiently without any influence of toner particles. Consequently, the cleaning effect is improved without using any intense light source and the image forming device is reduced in size and has high performance.

Description

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

In particular, it relates to a static eliminator.

[Prior art]

The prior art will be explained with reference to the accompanying drawings.

FIG. 1 shows an example of a conventional electrophotographic copying apparatus.

The copying device includes a charging device 1. Exposure device 2. Developing device 3. Transfer device 4. It consists of a cleaning device 5 and an eraser device 6, which are sequentially arranged around a drum-shaped photoreceptor 7.

In this embodiment, each of the steps of charging, exposure, development, transfer, neutralization, and cleaning are performed continuously during one rotation of the photoreceptor 7 to perform a copying operation.

In addition, as another conventional example, while the photoreceptor 7 rotates twice,
There was one that was configured to perform copying.

In the copying apparatus having the following configuration, the charging device 1 charges the entire surface of the photoreceptor 7 to a predetermined potential by corona discharge or the like. A lens is placed on the surface of the charged photoreceptor 7.

An exposure device 2 consisting of a combination of mirrors and the like exposes a document image to light, and the potential of the photoreceptor 7 is attenuated depending on the amount of light received, forming an electrostatic latent image.

The electrostatic latent image is developed by the developing device 3 by I, which has a charge of opposite polarity to the charge on the surface of the photoreceptor 7, and is visualized.

The visualized tri-image is transferred onto the paper by the transfer device 4 by applying a potential with a polarity opposite to that of the 1-S by a Jrona discharge.

The paper on which the image has been transferred is separated from the photoreceptor 7 by a 1-separator 9, conveyed to a fixing section 10 by a belt, and after the 1-toner image is fixed by heating or the like, it is discharged outside Ia.

On the other hand, about 20% of the toner and a certain level of residual charge remain on the photoreceptor 7 after the toner image is transferred to the paper.

To remove these, residual charges and toner.

The photoreceptor 7 is neutralized and cleaned by the static eliminator 8 and the cleaning device 5.

[Problems with conventional technology]

In these conventional copying machines, when removing residual charges on the photoreceptor 7, eraser light or the like is applied from the surface of the photoreceptor 7 as shown in FIG.

Therefore, the areas shaded by the toner particles are not sufficiently defrosted, and a large amount of eraser light must be irradiated to improve the static elimination efficiency.

Furthermore, when irradiating the eraser light with a strong intensity of 1, there was a risk that the photoreceptor 7 would be fatigued. Another drawback was that it was susceptible to stains caused by scattered toner.

On the other hand, if the static eliminating device 8 uses a method of eliminating static electricity by high-pressure corona discharge, the device is expensive.

This requires a large mechanical space, making it impossible to downsize the copying device.

In addition, it is difficult to obtain stable corona discharge because it is susceptible to dirt.

Furthermore, because it is not possible to uniformly weaken the electrostatic adsorption force between the residual I-ner and the photoreceptor, uniform leaning cannot be performed.

[Purpose of the invention]

In view of the above-mentioned conventional drawbacks, an object of the present invention is to sufficiently eliminate residual charges on the surface of a photoreceptor, improve cleaning efficiency, increase performance, downsize the device, and provide an inexpensive image forming device. shall be.

[Key points of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus including at least a transfer device and a charging device around a photoreceptor, on the downstream side of the transfer device.

The present invention is characterized in that a static eliminator that irradiates light from the back surface of the photoreceptor is provided upstream 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. 2 is a block diagram of an image forming apparatus showing an embodiment of the present invention.

In FIG. 2, a charging device 19. Developing and cleaning device 20, transfer device 2
1. Separation device 26. Eraser lamp 223 and toner disturbance member 23 are arranged in sequence.

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

The photosensitive member 18 is formed into a hollow cylindrical shape as shown in FIG. 3, and has an electrode layer 40° and a photosensitive layer 41 laminated on the outside of a transparent drum 39. The transparent drum 39 is.

It is extruded from transparent acrylic resin, vinyl chloride resin, etc., and has a cylindrical shape with a wall thickness of about 1 to 4 vA, and two surfaces are smoothed.

The electrode layer 40 has a thickness of 1 μm or less and is made of a conductive resin or the like, and is preferably made of a material as transparent as possible, but the thickness is about 1 μm.

Most resins transmit some light.

The photosensitive layer 41 is suitably made of a highly transparent photosensitive material such as an organic photoconductive material (OPC).

Further, the circumferential length of the photoreceptor 1B is shorter than the maximum transfer paper size on which an image is to be formed, and when the transfer paper size is A4, a photoreceptor 1B having a diameter of about 50 mm, for example, 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/cleaning device 20 is configured to perform both development and cleaning, and eleven developer particles are deposited on the surface of the sleeve 20a so as to rub 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 for applying a charge having a polarity opposite to that of the toner of the developer used from the transfer line.

The eraser lamp 22 is a light source for optically eliminating the residual charge on the S light body 1B, and is used inside the photoconductor 18, which is formed in the shape of a hollow drum and rotates in the direction of the arrow, to the transfer device 2.
1 and upstream of the charging device 19. In particular, it may be at a position facing the toner disturbing member 23.

The I/ner placing 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 constructed of a well-known separation heald system, for example, and the fixing section 27 is constructed of a pair of pressing and rotating heat rollers 27a, 2'7b.

On the other hand, the original used for forming one image is inserted from the input direction at the top of the main body of the apparatus, 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 potential 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, 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. That is, the developer adhered to the sleeve 2Oa rubs the sleeve 2Oa, 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 the timing with the visible image on the photoreceptor 18 is matched, and the registration roller 33 sends it to the transfer section. 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 section 27, it is ejected from the paper discharge roller 35 to the outside of the machine.

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 photoconductor 18 is shorter than the maximum size of transfer paper that can be used, so for example, if an image is to be formed on a transfer paper that is longer than the circumference of the photoconductor 18, the transfer process is completed. Subsequently, an image forming step is further performed continuously. That is, after the transfer process of the portion corresponding to the leading edge of the document is completed, the photoreceptor 18 subsequently enters a charge removal process, and the charge remaining on the surface of the photoreceptor 18 is erased by the eraser lamp 22. Here, since the eraser lamp 22 is provided inside the translucent photoreceptor 18, residual toner particles do not form a shadow and interfere with charge removal.

Furthermore, 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, the residual toner is uniformly distributed on the photoreceptor I8 by the toner disturbance member 23. Disturbed.

This toner agitating member 23 does not have the ability to clean the residual toner, but merely agitates the residual toner uniformly on the photoreceptor 18. In this embodiment, this toner disturbance member 2
Reference numeral 3 denotes an insulating bristle brush, preferably a member charged to the same polarity as the toner, and its effect can be sufficiently obtained by making it follow the photoreceptor 1B or by rotating it at a low speed.

After passing through the toner disturbance member 23, the photoreceptor 18 is charged to the charging device 1.
9, the exposure device 24 continues the exposure process for the first continuous sheet, and a new electrostatic latent image is formed on the surface of the photoreceptor 18. 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 step. 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 that involves more than one rotation of the photoreceptor 1B, one of the photoreceptors 1B is A special post-processing process for cleaning beyond rotation is included. That is, in this dedicated cleaning process, the charging device 19. Exposure device 24. With the transfer device 2I 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 the surface of the photoreceptor 18 to disturb the residual toner and contributes to improving the cleaning ability of the primary 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.

Although the above description has been made regarding an example of an apparatus that performs both development and cleaning, the present invention is not limited to this, and may be an apparatus that performs a normal continuous copying process.

FIG. 5 shows another embodiment of the present invention.
It has a four-layer structure including a transparent drum 39, a conductive layer 40, a CTL photoreceptor 41a, and a CGL photoreceptor 41b.

When configured as described above, the durability of the photoreceptor is improved.

〔Effect of the invention〕

As explained above, according to the image forming apparatus of the present invention, the eraser light can be applied from the back side of the toner particles without being affected by the toner particles.

The photoreceptor can be neutralized.

Therefore, since there is no need to use a powerful light source, the life of the photoreceptor can be extended.

Further, since the eraser is provided inside the back side of the photoreceptor, it does not take up space on the surface of the photoreceptor, making the device small and compact, and it is not affected by scattered toner.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional electronic copying apparatus, FIG. 2 is a block diagram of an image forming apparatus showing an embodiment of the present invention, and FIG. 3 is an enlarged cross-section of a photoreceptor used in the present invention. 4 is a partially enlarged sectional view of a photoreceptor, and FIG. 5 is a partially enlarged sectional view of a photoreceptor showing another embodiment of the present invention. 1.19...Charging device 2.24...Exposure device 3...Developing device 4.21...Transfer device 5...Cleaning device 6...Eraser device 7,18...Photoreceptor 8... Static eliminator 9... Separator 10.21... Fixing section 20... Developing base IJ-ning device 22... Eraser lamp 23... L・ner placement portion +A 26・... Separation device 2B ... Original glass stand 31 ... Manual feed stand 32 ... Paper feed roller 33 ... Registration roller patent applicant Casio Kotoki 1w Machine Co., Ltd. Same as above I.D. Co., Ltd. agent patent attorney Yoshiyuki Osuga

Claims (1)

[Claims] (1) In an image forming apparatus equipped with at least a transfer device and a charging device around the photoconductor, on the downstream side of the transfer device,
An image forming apparatus characterized in that the image forming apparatus includes a static eliminator that irradiates light from the back surface of the photoreceptor on the upstream side of the charging device.