JPS5811981A - Fixing method for tonor image - Google Patents

Abstract

PURPOSE:To obtain a picture with high resolution by pressure-fixing a recording element having a tonor image obtained by charging and inversion development on its recording layer after subjecting AC corona discharging or reversed corona discharging to said charging. CONSTITUTION:A recording element consists of a supporting element with a conductive surface and a photoconductive layer formed on the surface of the supporting element. If necessary, a transparent insulated layer is permitted to be formed on the photoconductive layer. Said photoconductive layer is charged, e.g., negatively by corona discharging at a dark place and exposed through a negative film to form an electrostatic latent image. Subsequently inversion development is performed to obtained a positive tonor image. By fixing the surface of the recording element after discharging the charge on the surface by AC corona or reversed polar corona discharging, a clear fixed tonor image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for fixing a toner image in which an electrostatic latent image formed by a photolithography method or an electrostatic recording method is developed by a reversal development method to form an image.

In electrophotography, an electrostatic latent image is formed by uniformly charging a photoconductor made of selenium, zinc oxide, an organic semiconductor, etc. and exposing it to an image, and in electrostatic recording, an electrostatic latent image is formed on a dielectric film, for example. An electrostatic latent image is formed by accumulating ions generated by the energized metal stylus. Usually, the electrostatic latent image created by these methods is developed with toner to form a toner image, and this is fixed to form a stable image.

In this case, the latent image has, for example, negative polarity7. ) If the image is developed with toner of positive polarity, the toner will adhere only to the latent image and the toner image will be clouded (Regular f7). However, when producing a positive image from a negative such as microfilm, one method is to apply toner to the unexposed areas (areas with no latent image) and apply toner to the latent image area. Just apply 5Vr to prevent it from sticking. In the above case.

In other words, if the latent image has a negative polarity, for example, if it is a stone, development is performed using toner with a negative polarity and without applying a bias voltage to direct the toner toward the latent image surface. A positive image can be returned by developing with an electrode (reversal development).In order to return a sharp and fog-free toner image by reversal development, the voltage applied to the developing electrode is equal to the charge of the latent image. It is essential that the voltage be equal to or higher than the voltage of , thereby eliminating the adhesion of toner particles to the latent image area and ensuring the adhesion of toner particles to the uncharged area. I can do it.

When performing reversal development using a charged toner, that is, a two-component toner consisting of toner and carrier, a single developing pole is used during development, and a developer with the same polarity as the latent image and the same "Ichikawa or higher" polarity is used during development. Toner development is performed by applying a bias voltage.

In liquid development, reversal development can also be performed by a similar operation. For example, when using a one-component toner that uses conductive magnetic toner that contains iron oxide powder in a resin and is magnetically attracted and intoxicated, one of the toners is rotated once.
- Using a magnetic roller and a conductive or insulating sleeve provided around it, magnetic toner is supplied to the surface of the sleeve, and by rotating the magnetic roller and/or sleeve, the toner overflows to the outer periphery of the sleeve. (The latent image is developed by moving it and bringing it into contact with the recording medium that has the latent image.

In such systems, a latent image is formed on the doctor blade in contact with toner that is magnetically attracted to the sleeve, if the sleeve is conductive, or to the sleeve, if the sleeve is insulative. (with the same polarity as the latent image and a pressure equal to or larger than that of the latent image); reversal development can be performed by applying an insulating pressure.

The toner image (which becomes a negative-positive mode image with respect to the original) created by reversal development in this way has toner attached to areas where there is no latent image, that is, areas where there is no electric charge, and the latent image There is no Tonai family in the part, and the electric charge remains. Since the toner after development is mostly attached to or on the non-charged area, in order to form a stable image, the toner image must be fixed as in the case of normal development. As the fixing method, thermal fixing by heating, fixing by solvent, pressure fixing by pressure roll, etc. are used. Heat fixing requires a heat source for heating.

This has led to problems such as having to wait until the heater reaches a certain temperature before starting the equipment, and preventing solvent leakage and removing the solvent. Reduce the cost of equipment incidental to collection,
In some cases, risks such as ignition must also be considered. Therefore, there is no such drawback and it can be operated immediately when used.

It has become desirable to use pressure fixing, which is advantageous in terms of energy saving and does not require a heat source.

In pressure fixing, fixing is performed by passing a recording medium having a developed toner image through two or six pressure rollers to fix the toner image on the recording medium.

However, when applying pressure to a toner image that has been released by normal development, there is no problem since the toner image adheres relatively firmly to the latent image due to the atmospheric suction force, but reversal development is superior. When a toner image is fixed under pressure, there are drawbacks such as a portion of the toner being transferred to the metal roller and the peripheral edges of the toner image being blurred so that the sharp image cannot be underestimated.

The inventors of the present invention have conducted 11 studies to improve the above-mentioned drawbacks that occur when a toner image that has been blown away by the reversal phenomenon is fixed by pressure.
．． It has been found that -C is induced by the charge existing in the electrostatic latent image area.

That is, lines of electric force are generated between the charges existing in the electrostatic latent image area and the pressurized metal roller. As a result, a portion of the toner image is pulled apart.

The present inventors succeeded in removing the latent image charge and returning a sharp fixed image by exposing the surface of the recording medium to alternating current corona or reverse corona discharge in order to prevent the generation of upper Rosa 1 air lines.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of producing an extremely sharp reversal toner image by pressure fixing.

The above object is achieved in accordance with the present invention by pressure fixing a recording material having a toner image maintained by charge and reversal development on the recording layer after exposure to alternating current corona or reverse corona discharge.

The method of the present invention is a toner image damaged by reversal development using a two-component dry development method consisting of toner and carrier, a magnetic plan development method 5g one body development method, a one-component development method using Ise-prone toner R, etc. Can be applied to pressure fixing. In electrophotography, the recording medium basically consists of a support whose surface is at least electrically conductive and a photoconductor layer provided on the support, and a transparent insulator layer may be placed on the photoconductor layer depending on the need. may be provided. There is no limit to the percentage of these materials, and materials generally used in the Hoichiko photography method are used.
I can do that. For example, conductive supports include conductive paper or plastics with a conductive layer on the surface, and photoconductors include inorganic photoconductors such as selenium, selenium alloys, zinc oxide, and cadmium sulfide. Examples include organic photoconductive substances such as polyvinylcarbazole, organic pigments, and organic semiconductors, and the above-mentioned inorganic photoconductors can also be used as a mixed system with a suitable resin. A transparent plastic such as gelatin is suitable for the insulating layer. Father, in the electrostatic recording method, the recording medium basically has at least the surface
It consists of a support with J= and a dielectric layer thereon, and the support may be the same as described above, and the n-electric layer may also be the same as the insulating layer described above.

Although the present invention can be applied to various types of developing methods as described above, an example in which a -component type magnetic toner is used will be explained.

First, the recording layer is negatively charged, for example, in a dark place using corona radiation. It is then exposed to light, for example through a negative film, to create an electrostatic latent image. Next, this is developed, and reversal development is performed to make the positive toner image brighter. That is, 1, for example, toner development is performed by applying a negative voltage bias equal to or greater than that of the electrostatic latent image to the sleeve of a developing roll (magnetic roll). As a result, since negative charges have been induced in the toner f, the toner f repels the negative charges in the latent image area and does not adhere to this area, and since the non-latent image area is charged, the bias voltage of the sleeve is reduced. (There is a potential difference between the pressure and pressure, and the toner adheres only to this area.)

Next, the upper surface of the recording medium is exposed to an alternating current corona or a corona of opposite polarity to remove the charge on the recording body surface, and then the toner is fixed, thereby producing a sharp fixed toner image. Furthermore, it can be understood that with regard to electrostatic latent images formed on dielectric materials by recording, a sharp image can be produced by applying an alternating current corona or a corona of opposite polarity.

Defrosting using AC corona or reverse polarity corona according to the present invention,
This is done to eliminate the charge on the surface of the recording layer until it reaches a level that does not generate lines of electric force large enough to attract the toner to the pressure roller, and the amount of corona discharge is The amount can be arbitrarily selected from the amount that neutralizes at least a part of the charge remaining on the surface to the amount that neutralizes almost all of the charge. Furthermore, when the charge is removed by a reverse polarity corona, the surface of the recording layer remains. The amount up to the point where the polarity is slightly opposite to that charged can be arbitrarily selected.

Although the above description has been made using a one-component development system using magnetic toner as an example, it is easily understood that the present invention can also be applied to pressure fixing of toner images returned by reversal development using other development systems. .

As described above, according to the present invention, a fixed toner image with high sharpness can be obtained by pressure fixing a toner image that has been fixed by one reversal development using extremely simple means.

For example, it can be advantageously used when performing negative-positive electrophotographic copying with a microfilm printer or the like.

Hereinafter, the present invention will be explained by examples.

Example The following experiment was conducted as a comparative example.

Positive development: The surface of a photoconductive body made of zinc oxide is set to a surface potential of approximately 500 V at Corona Teiho.

- Image exposure is performed on this using an electrophotographic society destchard/i61-T through a 1=1 optical system.

Φ When this was developed with -component magnetic toner to form a toner image in positive-positive mode on the document and passed through a pressure fixing machine, it resolved 661ine sheets on the resolution chart, and the minimum 6 points for characters appeared. .

Make a latent image charge in the same way as for normal development.

Developing with one-component magnetic toner while applying a bias voltage of -600 to -800 to the sleeve of the developing roll 12
After forming a negative-positive mode toner image on a document, it is passed through a pressure fixing device.

On the resolution chart, 2.5 xines/- was finally resolved.

The minimum character of 6 points is completely unrecognizable, and 10 points is the minimum character.

Reversal development @ (method of the present invention) An image profile is created in the same manner as normal development, and this is developed with a one-component magnetic toner under the same conditions as the above-mentioned reversal development. After forming a dimode toner image,
QF recording pot body surface exchange, back accumulation corona, and pressure fixation, resolution chart is 6.611ne 5Aurr
A fixed toner image was developed that could distinguish the smallest 6-point character.

Agent: Patent attorney (8107) Kiyotaka Sasaki (and 6 others)

Claims (1)

[Claims] (1) A recording body having a toner image formed by charge and reversal phenomenon on the recording layer is heated by alternating current corona discharge or by
A method for fixing a toner image, which is characterized by fixing a toner image under pressure on a corona discharged against Vr.