JPS6057863A - Toner image transferring method - Google Patents

Abstract

PURPOSE:To transfer an image of good quality efficiently without exerting any evil influence of residual ozone upon a photosensitive body, etc., by exposing the rear surface of a recording body in a transfer area through an opening part provided to the cover plate of a transfer electrode when a toner image on the photosensitive body is transferred by supplying a corona ion flow from the rear surface of the recording body. CONSTITUTION:The discharging wire 12 of a corona discharger 10 provided in parallel to the drum shaft of the photosensitive body 4 is applied with a DC voltage which differs in polarity from toner 5. The opening length l of the opening part 131 provided to the cover plate 13 is larger than the width of a maximum image formed on the photosensitive body 4, and the opening width W is determined according to the quantity of light with which the photosensitive body 4 is irradiated by an illumination lamp 19 through the recording body from the opening part 131. There is a gap left between the opening part 131 and light source 19, so ozone generated when the corona ion flow is formed by the discharging wire 12 flows out without staying in a back plate 13 and is decomposed, so that the photosensitive body 4 never deteriorates in performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an improvement in a toner image transfer method for transferring to a recording medium.

[Prior art]

As a toner image transfer method for transferring a toner image formed on a photoreceptor onto a recording medium, a toner image transfer method using a corona discharger is often used. In this toner image transfer method, as shown in FIG.
By applying a DC voltage to and grounding the cover plate 3, or further applying a DC voltage to a scorotron grid (not shown), the toner 5 on the photoconductor 4 is applied to the back surface of the recording medium P by the discharge wire 2. Pour a constant stream of corona ions of opposite polarity with a charge of . As a result, the recording medium P is transferred to the photoreceptor 4.
The upper toner 5 is charged to a polarity that attracts it, and the toner image on the photoreceptor 4 is transferred to the recording medium P in the transfer area alc. The recording medium P onto which the toner image has been transferred is separated from the photoreceptor 4 by a separation means such as a separation electrode 7 or a belt in the figure, fixed thereon, and then discharged from the apparatus.

This transfer method using a corona discharger does not require a special adhesive transfer material as in adhesive transfer, and there is no risk of toner image collapse as in adhesive transfer or electrostatic transfer using an electrode roller. This method is said to have the advantage of not only having a relatively high transfer effect, but also having a simple device configuration.

However, if the charge retention of the recording medium P decreases due to humidity or other causes, the transfer efficiency may drop, and if the direct current corona ion flow is strengthened to increase the transfer efficiency, the corona ion flow in the transfer area a charge is injected into the toner 5 through the recording medium P, and the toner 5 is charged with the same polarity as the charge of the corona ion flow.
The toner may be repelled by the toner, which may actually reduce the transfer efficiency or cause image disturbance of the toner image, or it may be attracted by the strongly charged recording material P, causing the recording material P to come into close contact with the image carrier 4. Even in the pre-transfer area, which is an area where no transfer should be performed prior to the previous transfer area a, the image carrier 4
A part of the upper I-ner 5 transfers to the recording medium P, and this also causes image disturbance.

Therefore, in order to improve these defects and achieve stable and good transfer, as proposed in Japanese Patent Publication No. 55-14428 and Japanese Patent Publication No. 55-45910,
It is known that irradiating an image bearing member holding a toner image with light before transfer is effective for transfer. In FIG. 1, reference numeral 8 denotes an exposure lamp provided in the pre-transfer area, which irradiates the toner image from above before the transfer. That is, when an image carrier having residual charges is irradiated with light, the charges on the image carrier are erased. The bond between the image carrier and the toner is strong when they are electrically bonded and attached, but weakens after the charge disappears.

Therefore, the rate at which toner particles are transferred to the image carrier or the recording medium by the corona discharger, that is, the transfer efficiency is improved.

However, this proposal has the problem that the attraction force between the image carrier and the toner image is reduced, which causes electrostatic repulsion between the toner particles, causing toner scattering before transfer and deteriorating image quality. are doing.

Here, the one that attempted to improve the above drawback was published in JP-A-57-1.
This is a proposal based on Publication No. 1368. In this proposal, a DC voltage is applied to the image bearing member in the transfer area by a voltage application device, and at the same time exposure is performed by an irradiation device.This prevents the toner particles from repelling each other and disturbing the image before transfer, and also reduces the applied voltage. With this proposal, stable toner image transfer is possible regardless of environmental humidity.

This proposal suggests voltage application means using a corona discharger, an electrode roller, etc. as the DC voltage application means. However, the exposure conditions differ depending on the voltage application means, and it is not easy to expose the photoreceptor to light at the same time as the transfer area is charged. The photoreceptor is then exposed to light. Further, as described above, corona charging means using a corona discharger is excellent as a direct current voltage applying means for transfer. However, Coronachia-9 means easily generates ozone, and ozone during the generation stage may impair the characteristics of the photoreceptor. The above proposals do not sufficiently address these issues.

[Purpose of the invention]

The present invention improves the transfer method in which the toner image on the photoreceptor is transferred by applying a corona ion flow from the back side of the recording member in the transfer area, and the ozone generated by the corona charge stays on the photoreceptor, etc. A toner that does not have any adverse effects and that allows the photoreceptor to be irradiated with the necessary amount of light that has passed through the recording medium, so that a high-quality image can be stably and efficiently transferred onto the recording medium regardless of environmental humidity. The object of the present invention is to provide an image transfer method.

[Structure of the invention]

The present invention aims to achieve the above object by applying a corona ion flow to the toner image adhered to and formed on the electrostatic latent image surface of the photoreceptor from the back surface of the recording member using a transfer pole. In the transfer method, the transfer is carried out by a light source placed behind the cover plate of the transfer pole, exposing the back side of the recording body in the transfer area through an opening provided in the cover plate. This is achieved by a toner image transfer method.

〔Example〕 An embodiment of the present invention will be described with reference to the sectional view of FIG.

The same parts as those of the conventional device are given the same reference numerals, and the explanation thereof will be omitted. A DC voltage having a polarity opposite to that of the charging of the toner 5 is applied to the discharge wire 12 of the corona discharge device 0 according to the present invention, which is provided parallel to the drum axis of the photoreceptor 4, and the cover plate 13 is grounded. The cover plate 13 has a U-shaped cross section as shown in the perspective view of FIG.
It is a metal member having a length in the direction of the drum axis, and an opening 131 according to the present invention is provided therein. The opening length e of the elongated rectangular opening 131 provided in the direction of the drum axis is greater than or equal to the maximum image width formed on the photoreceptor 4. Further, the opening width W in the drum rotation direction is determined according to the amount of light irradiated from the opening 131 onto the photoreceptor 4 through the recording medium P by an illumination lens 19, which will be described later. The first opening 131 may be provided with an opening reinforcing section 132 as appropriate, and the opening 131 may be divided and reinforced. However, lighting lamp 19
The opening reinforcing portion 132 is arranged so that the exposure yL distribution through the recording medium P and onto the photoreceptor 4 is uniform in the drum axis direction.
It is necessary to make the width small. Alternatively, if both ends of the corona discharger are reinforced and a strong back plate is used, the opening reinforcing portion 132 is not necessarily required.

Behind the cover plate 13, a tubular illumination lamp 19 such as a fluorescent lamp is provided parallel to the drum axis of the photoreceptor 4. A lighting cover 19 is provided on the side and behind the lighting lamp 19.
1, and a filter 192 and a cylindrical condenser lens 193 for collecting lens 0 are provided facing the opening 131. The filter 192 is a yellow filter that absorbs light on the short wavelength side, and has the effect of suppressing deterioration of the photoreceptor 4.

The light from the illumination lamp 19 passes through a filter 192,
The photoreceptor 4 in the transfer area a is irradiated from the opening 131.

The amount of light irradiated onto the photoreceptor 4 is the amount of light emitted by the illumination lamp 190.
c amount, condensing efficiency of condenser lens 193, aperture 13
It is determined by the aperture width W of 1, the size of the recording medium, the thickness of the paper, etc., and the amount of irradiation light is preferably 1O~200 on the photoreceptor surface.
(Light intensity of lz-sec, more preferably 10ν10
It is desirable that it be 0 ez-sec. i.

When the amount of light is less than e-sec, the amount of light reaching the photoreceptor is insufficient, and the effect of exposing the photoreceptor to light at the same time as charging is not recognized. Moreover, 200 (lz -sec
Irradiation with more than a certain amount of light causes a potential drop due to photodeterioration of the photoreceptor, resulting in a decrease in image density, which is undesirable.

In addition, the opening 131 and light source 19 newly provided according to the present invention.
Since a gap is provided between the discharge wire and the corona iodide flow, the ozone generated when the corona iodide flow is generated from the discharge wire does not accumulate in the back plate 13 (flows out from the opening 131 and decomposes to the outside, causing the ozone to be felt at °C). The performance of the body 4 is not deteriorated.

In addition, the second. In the embodiment shown in FIG. 3, an opening 131 is provided just behind the discharge wire 12, but the provision of this opening 131 may make the discharge somewhat unstable. Figure 4 shows an attempt to avoid this, and the back plate n
has a U-shaped cross section, an opening 231 is provided at a position away from directly behind the discharge wire n, and the transfer area a is exposed through this opening 231.

Also second. In the embodiment shown in FIG. 3, the filter 192 also has a dust-proofing effect to prevent the illumination lamp 19 from becoming dirty with toner or the like. In this example, filter 19
2. Although the condenser lens i93 is provided as a separate body, it is also possible to use both as one body, or both may be omitted depending on the situation.

〔Effect of the invention〕

According to the present invention, ozone generated in the transfer area no longer remains and adversely affects the photoreceptor and the like. Furthermore, by irradiating the photoreceptor in the transfer area, efficient toner image transfer is achieved regardless of environmental humidity, resulting in highly reliable and stable transfer.

[Brief explanation of drawings]

FIG. 1 is a partial configuration diagram of an electrophotographic recording apparatus showing a conventional transfer method. FIG. 2 is a sectional view of a main part showing one embodiment of the present invention, and FIG. 3 is a perspective view of this main part. FIG. 4 is a perspective view of main parts of another embodiment. 1.10.20... Corona discharger 2.12,2
2... Discharge wire 3.13, 23...
Cover plate 4... Photoreceptor 5... Toner 19... Illumination lamp 131, 231... Opening (cover plate) 132, 232... ...Aperture reinforcement part (cover plate) 191...Lighting cover 192...Filter 193...Condenser lens agent Yoshimi Kuwahara 51

Claims (1)

[Claims] The toner image attached and formed on the electrostatic latent image surface on the photoreceptor,
In a transfer method in which transfer is performed on a recording medium in a transfer area by applying a corona ion flow from the back surface of the recording medium using a transfer pole, the transfer is performed on the cover plate by a light source disposed behind the cover plate of the transfer pole. A toner image transfer method characterized in that the K11S light from the back surface of the recording medium in the transfer area is transmitted through the opening.