JPS61116374A - 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 [Field of Industrial Application] The present invention relates to improvements in image forming apparatuses such as laser printers, and particularly relates to an image forming apparatus that forms a toner image on a photoreceptor irradiated with image light. .

The photoconductive layer of a photoconductive drum, which has a photoconductive layer such as selenium (Se) formed on its surface, is uniformly charged, and the charged photoconductive layer is irradiated with laser light based on printed information to form an electrostatic latent image. An electrophotographic apparatus such as a laser printer is well known, which forms a toner image by attaching a chargeable toner to the latent image formation area and performing development, and transfers and records this toner image onto recording paper.

[Conventional technology]

Such a laser printer device will be explained using the schematic diagram of FIG. 4.

As shown in the figure, the surface of a recording drum 1 on which a photoconductive layer 2 such as Se is formed is uniformly charged using a corona discharger 3 for initial charging. Next, the photoconductive layer 2 is irradiated with laser light using the laser light source 4 to perform exposure corresponding to image information to form an electrostatic latent image. Further, toner charged to the same polarity as the uniformly charged charge is electrostatically attached to this electrostatic latent image by an electric field using a developing device 5 to form a toner image.

Further, the toner image on the photoconductive layer 2 is transferred to a recording paper 10 charged with an electric charge of opposite polarity to that of the toner by a transfer corotron 6.
It is transcribed and recorded above. The toner image thus transferred onto the recording paper is fixed onto the recording paper 10 by heat fixing, pressure fixing, or the like by the fixing device 7.

On the other hand, the toner remaining on the photoconductive layer 2 is subjected to a treatment such that the charge of the toner is neutralized by the static eliminating corotron 8 and the toner is easily removed from the photoconductive layer 2.
Clean and remove with a cleaner 9 consisting of a bristle brush. Furthermore, by reducing the surface potential of the photoconductive layer 2 to approximately 0■ using a static eliminating corotron, image recording is completed through a series of processes from initial charging to cleaning salt for residual toner, and this recording process is repeated to prevent continuous crime. ,
Recording will take place.

[Problem that the invention seeks to solve]

By the way, in such conventional image forming apparatuses, the photoreceptor has a certain amount of dark resistance even when no light is irradiated, so the inverse resistance corresponding to the electric charge of a layer of charged toner that adheres to the surface of the photoreceptor during development occurs. Polar charges are injected into the photoreceptor from the conductive base of the photoreceptor drum while the photoreceptor moves from the developing device to the transfer device.

Therefore, during transfer, this injected charge becomes a trapped charge, and this trapped charge binds the charged toner attached to the surface of the photoreceptor to the photoreceptor, and the charged toner cannot be sufficiently transferred to the recording paper. Therefore, there is a problem that the transfer efficiency is reduced and clear transfer recording is not possible.

[Means for solving problems]

The above-mentioned problem is caused by a photoreceptor in which a transparent conductive film and a photoconductive film are sequentially laminated on a transparent substrate, and
a charging device for the photoreceptor in the moving direction of the photoreceptor;
An exposure device that exposes a charged photoconductor to light in accordance with an image pattern, a developing device that supplies toner to the exposed photoconductor and develops it, and a transfer device that transfers the toner image developed on the photoconductor onto recording paper. A light source for transfer is provided at a position opposite to the toner image transfer device via the photoreceptor, and a light shielding plate is further provided for blocking light from the photoreceptor from the charging device for the photoreceptor to the developing device. After the toner image is developed on the photoreceptor, a transfer device is used to electrostatically transfer the toner image to a recording paper by irradiating the photoreceptor with a transfer light source to eliminate the trapped charges inside the photoreceptor. In this book, the charged toner is transferred onto recording paper while the charges induced on the photoreceptor by transfer are guided to the surface of the photoreceptor, and the charges of the charged toner and the induced charges are electrostatically repelled. The problem is solved by the image forming apparatus of the invention.

[Effect]

That is, the image forming apparatus of the present invention uses a transparent photoreceptor in which a transparent conductive layer is provided on a transparent substrate and a photoconductive film is provided thereon, and a transparent photoreceptor is provided at a position facing a transfer device from the transparent substrate side of the photoreceptor. A light irradiation device is provided to irradiate the charged toner onto the recording paper, and when the charged toner is transferred onto the recording paper, the light is irradiated from the back side of the photoreceptor to transfer and record a layer of toner attached to the surface of the photoreceptor onto the recording paper.
The trapped charges injected into the photoreceptor from the transparent conductive film during the movement time of the photoreceptor from development to transfer are extinguished. Furthermore, this light irradiation induces a charge on the surface of the photoconductor with the opposite polarity to the charged toner attached to the surface of the photoconductor, and by utilizing the electrostatic repulsion between the photoconductor and the charged toner, it is possible to efficiently coat the recording paper. The toner image is electrostatically transferred and recorded.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a first embodiment of the image forming apparatus of the present invention.

As shown in the figure, a transparent substrate 11A made of a polyethylene terephthalate film with a thickness of 100 μl is coated with a thickness of 0.2 μl.
A photoreceptor (manufactured by Kodak, product name: 5
O-102) 11 is pasted on a hollow glass drum 12 and moved along the six directions of arrows at a circumferential speed of 10 am/sec.

A cleaner brush 13 is provided outside the photoreceptor 11 as a toner removing means. Furthermore, a corona discharger 14 is provided as a means for charging the photoreceptor 11 on the surface side of the photoreceptor 11 in close proximity to the photoreceptor 11, and as a means for supplying toner, a corona discharger 14 is used as a means for supplying toner. A two-component magnetic brush developing device 15 is provided at a position separated by a predetermined distance, and a light emitting diode array 17 and a selfoc lens 16 are provided between the corona discharger 14 and the developing device 15 as image exposure means.

Furthermore, a corona discharger 18 was provided as a transfer device on the back side of the recording paper 19, and a transfer light source 20 and a cover 21 for this light source 20 were provided inside the glass drum 12 at a position opposite to the corona discharger 18. Also, the corona discharger 14 of the charging device
In order to shield the photoreceptor of the developing device 15 from light, light shielding plates 22A and 22B are provided on the front and back sides of the photoreceptor 11, respectively.

The operation of the image forming apparatus of this embodiment will be described.

First, using the corona discharger 14, the photoreceptor 11 is uniformly coated with 50%
Charge it to 0■. Next, the photoreceptor is exposed to light according to the image pattern using the light emitting diode array 17, and the uniformly charged charges are selectively removed to form an electrostatic latent image. Next, a developing bias voltage V of 400 V is applied to the magnetic brush developing device 15, and the positively charged toner is caused to adhere to the surface of the photoreceptor by an electric field, thereby forming a toner image 23. Further, a negative voltage is applied to the corona discharger 18 to give negative corona ions to the back surface of the recording paper 19, and at the same time, the transfer light source 20 is turned on.
The photoreceptor 11 is exposed from the back and side.

The principle of transfer at this time will be explained using FIG. 2. Second
FIG. 2(a) shows the state when a conventional image forming apparatus is used, and FIG. 2(a) shows the state when the image forming apparatus of this embodiment is used.

In the conventional image forming apparatus, as shown in FIG. Charges are injected into the photoreceptor 2, and the trapped charges 2
It becomes 4. At this time, when a charge 25 having a polarity opposite to that of the charged toner is applied to the recording paper 10, an induced charge 26 appears on the substrate in response to this.

However, because the electrostatic force between the trapped charges 24 and the charged toner 23 is strong, complete transfer to the recording paper is not performed.

On the other hand, when the image forming apparatus of this embodiment is used as shown in FIG. 2(b), since light is irradiated from the transparent substrate 11A side during transfer, the trapped charges 24 are dissociated by the light. It flows to ground via the transparent conductive layer 11B. Furthermore, the positive charges 26 induced by the negative charges applied to the recording paper 19 are transferred to the photoconductive layer 11 whose resistance has become low due to the light irradiation.
This appears on the surface of the G, and this and the charged toner 23 electrostatically repel and are easily transferred, improving transfer efficiency.

The toner image transferred in this manner is fixed by a fixing device (not shown) and recorded as a permanent image on the recording paper. - A small amount of toner remaining on the surface of the photoreceptor is completely removed by the cleaner 13, and the above-described recording process is then repeated.

FIG. 3 shows a second embodiment of the image forming apparatus of the present invention,
The difference from the first embodiment is that a light emitting diode array 17 serving as a light source for image exposure and a SELFOC lens 16 are provided inside the photoreceptor 11.

In this embodiment, all the light sources and the surface to which charged toner is attached are
Since they are completely separated with the photoreceptor 11 in between, the optical system is not contaminated by floating toner.

Furthermore, even if a filming phenomenon occurs in which toner sticks to the surface of the photoreceptor during continuous print recording, there is an effect that sensitivity does not decrease because the light is irradiated from the back side of the photoreceptor.

In the embodiments of the present invention, a recording medium in which a transparent photoreceptor film was pasted on a glass drum was used as the recording medium, but it is of course possible to use a photoreceptor film in the form of an endless belt. Furthermore, a recording medium may be used in which a transparent conductive film is directly provided on a glass drum without forming a transparent base film, and a photoconductive film is formed thereon.

Further, in this embodiment, a corona discharger was used as the charging device and the transfer device, but other contact chargers such as a conductive roller, a conductive belt, and a conductive brush may be used. Furthermore, although a two-component magnetic brush developer is used as the developer in this embodiment, other developers, such as a one-component magnetic brush developer, a cascade developer, or a liquid developer may be used. Furthermore, although a brush cleaner is used as the toner removing device in this embodiment, other blade cleaners or magnetic brush cleaners may be used as the toner removing device.

〔Effect of the invention〕

As described above, according to the image forming apparatus of the present invention, since light is irradiated from the inside of the photoreceptor during transfer, it is possible to eliminate trapped charges caused by dark decay of the photoreceptor, and also to transfer the image onto the recording paper. Inductive charges induced on the photoconductor by light irradiation appear on the surface of the photoconductor in response to the charges given by the device, and this induced charge and the charged toner electrostatically repel, causing the charging to occur. The transfer efficiency of toner to recording paper is improved, and clear print recording becomes possible.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the first embodiment of the image forming apparatus of the present invention, and Fig. 2 shows the state of the photoreceptor near the transfer device when the image forming apparatus of the present invention is used. FIG. 3 is a schematic diagram showing a second embodiment of the image forming apparatus of the present invention, and FIG. 4 is a schematic diagram showing a conventional image forming apparatus. In the figure, 11 is a photoreceptor, IIA is a transparent substrate, 11B
is a transparent conductive film, IIG is a photoconductive film, 12 is a glass drum, 13 is a cleaner, 14.18 is a corona discharger, 15 is a developer, 16 is a selfoc lens, 17 is a light emitting diode array, 19 is a recording paper, 20 is a light source, 21, 22A
. 22B is a light shielding plate, 23 is a charged toner, 24.25.26
is the electric charge in Fig. 1, Fig. 2 [(1), Fig. 2, tbl, Fig. 3; Fig. 4, 2'.

Claims (1)

[Claims] A photoreceptor in which a transparent conductive film and a photoconductive film are sequentially laminated on a transparent substrate; a charging device for the photoreceptor that is adjacent to the photoreceptor in the direction of movement of the photoreceptor; and a photoreceptor that can be charged. An exposure device that exposes light in accordance with an image pattern, a developing device that supplies toner to the exposed photoreceptor and develops it, and a transfer device that transfers the toner image developed on the photoreceptor onto recording paper are provided, respectively. In addition, a light source for transfer is provided at a position opposite to the toner image transfer device via the photoreceptor, and a light shielding plate is provided to shield the photoreceptor from the charging device for the photoreceptor to the developing device from light. After a toner image is developed on a body, when the toner image is electrostatically transferred to a recording paper using a transfer device, a transfer light source is irradiated onto the photoreceptor to eliminate trapped charges inside the photoreceptor, and An image characterized in that the charges induced on the photoconductor by the transfer are guided to the surface of the photoconductor, and the charges of the charged toner and the induced charges are electrostatically repelled, while the charged toner is transferred onto the recording paper. Forming device.