JPH04309986A - Method and device for image forming - Google Patents

Abstract

PURPOSE:To provide an image forming method and device which can obtain a high quality image. CONSTITUTION:In this image forming method, a colloidal developing liquid having the dispersion of a conductive solid fine grain in an insulating solvent is used. The colloidal developing liquid 104 is supplied between a first electrode layer 101 having a photoconductive layer 103, and a second electrode layer 102 provided on a side via the photoconductive layer 103 so as to face the first electrode layer 101, and having the formation of a surface layer having adhesive power stronger than that of the photoconductive layer 103, with respect to the gel state part of the developing liquid, a voltage is applied between the first electrode layer 101 and the second electrode layer 102, and the photoconductive layer 103 is irradiated with light, so that an electrostatic latent image is formed on the irradiated part, the colloidal developing liquid 104 on the electrostatic latent image is turned into a gel state, and an electrical viscous fluid image having high viscosity is formed on the surface layer by the gel state part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel image forming method and apparatus applicable to a non-impact printer system.

0002

[Prior Art] Electrophotography is a non-impact printer method that can record high-speed, high-quality images on plain paper.
Electrostatic recording methods, magnetic recording methods, etc. are known. These methods have separate latent image forming sections and development forming sections, so
Due to the configuration of the device, it is extremely difficult to make it smaller and at a lower price. Furthermore, since a heat fixing process is required when transferring the image from the developing section to the image receiving paper, there is a problem in that a large amount of thermal energy is wasted. On the other hand, the image forming method using an electrorheological fluid described in Japanese Patent Application Laid-Open No. 58-27157 changes the viscosity of the liquid developer depending on whether or not an electric field is applied, thereby changing the transferability. In other words, while the developer in the line image area remains low in viscosity,
The developer in the non-latent image area is made to have a high viscosity. As a result, the developer for the non-latent image area remains on the surface of the recording medium without being transferred to the image-receiving sheet, and the low-viscosity developer for the latent image area is transferred to the image-receiving sheet, thereby obtaining an image. Compared to conventional non-impact printer systems, this method allows multiple copies of the same latent image to be obtained at high speed, and requires no heat fixing, resulting in less wasted thermal energy. Further, because the apparatus is configured so that latent image formation and development can be performed using common members, it is easy to simplify the size and reduce the cost.

0003

However, even with the above-mentioned conventional methods, several problems remain in order to obtain high-quality images.

First, in the latent image forming method, a latent image is created on a uniformly charged dielectric recording medium by neutralizing the charge in the latent image area with a pin electrode, but the resolution of this pin is Due to limitations, it is not possible to obtain latent images with high resolution.

Second, since the contact method uses pins, poor contact may occur due to poor contact on the dielectric recording medium or deterioration of the pins due to long-term use, and charge neutralization occurs in the process of forming a latent image. If this is not done properly, the recorded image will not be properly formed from the developer onto the dielectric recording medium, which will be a major cause of image deterioration.

Third, the developing solution in the latent image area is transferred to the image receiving sheet in a low viscosity state, but when it is absorbed onto the applicator roll of the image receiving sheet and transferred to paper, it is not as viscous as it is on plain paper. Because the liquid developer has low viscosity and high fluidity, smearing occurs on the paper, making it impossible to obtain high-quality images.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel image forming method and apparatus that can solve all of the above problems and obtain high quality images.

[0008]

Means for Solving the Problems In order to achieve the above object, the image forming method of the present invention is an image forming method using a colloidal developer in which solid fine particles having dielectric properties are dispersed in an insulating solvent, the method comprising: a first electrode layer having a photoconductor layer; a first electrode layer provided on a side facing the first electrode layer with the photoconductor layer in between; supplying the colloidal developer between the second electrode layer and the second electrode layer on which a surface layer having stronger adhesive force than the body layer is formed;
By applying a voltage between the first electrode layer and the second electrode layer and irradiating the photoconductor layer with light, an electrostatic latent image is formed on the irradiated portion, and the electrostatic latent image is The above colloidal developer is in a gel state, and a high viscosity electrorheological fluid image is formed on the surface layer by this gel state portion.

Further, the image forming apparatus of the present invention is an image forming apparatus using a colloidal developer in which solid fine particles having dielectric properties are dispersed in an insulating solvent, and wherein the first electrode layer has a photoconductor layer. and the colloidal developer is provided on the side facing the first electrode layer with the photoconductor layer interposed therebetween, and is provided at a distance such that the colloidal developer is supplied to the gel state portion of the developer. a second electrode layer on which a surface layer having stronger adhesive force than the conductor layer is formed;
The photoconductor layer is characterized by comprising a power source that applies a voltage between the photoconductor layer and the photoconductor layer, and a light source that irradiates the photoconductor layer with light.

First, a colloidal developer is supplied between the first electrode layer and the second electrode layer, and a constant voltage is applied between the two electrode layers. At this electric field strength, the dielectric solid particles dispersed in the insulating solvent do not electrophoretically move toward the electrode layer, which has a charge opposite to the polarity of the solid particles. Next, in this state, the photoconductor layer is irradiated with light. Then, the photoconductor layer irradiated with light changes from an insulating layer to an electrodynamic layer, and the electric field strength in that part becomes stronger than in the part not irradiated with light. Then, the solid fine particles dispersed near the irradiation part move due to the influence of their dielectric properties, and a chain of particle groups along the direction of the electric field is formed between the two electrode layers. This part becomes a kind of gel state,
The cohesive force is much stronger compared to the non-light irradiated area. Since the adhesive force between the surface layer and the gel state part is stronger than that of the photoconductor layer, the gel state part remains in close contact with the surface layer even after the electric field is turned off and the developer is removed from between the two electrodes. In addition, since the cohesive force between solid fine particle chains increases irreversibly, the electric field is
Even with FF, the solid particles in the gel state are not redispersed. Therefore, even after the two electrode layers are separated, the
A highly viscous gel state portion formed under a high electric field by light irradiation remains, allowing development and formation.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic image forming process and apparatus according to the present invention will be explained with reference to the drawings.

FIG. 1 shows a basic image forming apparatus used in this method. Reference numeral 101 denotes a first electrode layer, which includes a photoconductor layer 103. 102 is a second electrode layer, on which a surface layer 102a is formed. The surface layer 102a is composed of pigment aggregates, particularly ink aggregates having a gel composition (solid particles 104a and liquid 104b aggregate in a non-uniform state, and liquid 104b is taken in by the strong structure-forming force of the solid particles 104). ) has strong adsorption power. The photoconductor layer 103 has an absorption wavelength of light around 780 nm. 104 is a colloidal developer;
Pigment toner particles, containing strong dielectric material (solid fine particles)
104a dispersed in an insulating solvent. 105 indicates a power source.

First, as shown in FIG. 1, both electrode layers 101,
102 is filled with a colloidal developer 104, and a certain voltage is applied between both electrode layers 102,102. At this electric field strength, the dispersed toner particles 104a do not move electrophoretically to the charged electrode opposite to the polarity of the toner particles. Next, in this state, as shown in FIG. 2, the photoconductor layer 103 is irradiated with light having a wavelength of around 780 μm in a pulsed manner from a light source 106 consisting of a laser or an LED. Then, the portion of the photoconductor layer that is irradiated with light changes from an insulating layer to a conductive layer, and the electric field strength of that portion becomes stronger than that of a portion that is not irradiated with light. Then, the toner particles 104a dispersed near the irradiation part form a chain 107 of particle groups along the direction of the electric field between the two electrodes as shown in FIG. 2 due to the influence of the strong dielectric component contained in the toner material. do. This part becomes a kind of gel state and has a much stronger cohesive force than other non-light irradiated parts. Since the surface layer 102a has a strong adhesive force with the gel component, the developer 1 is applied from between the electrode layers 101 and 102 by turning off the electric field.
Even after removing 04, the gel state portion 108 remains in close contact with the surface layer 102a, as shown in FIG. In addition, since the cohesive force between toner particle chains increases irreversibly, turning off the electric field
Even so, the toner particles 104a in the gel state portion 108 are not redispersed. Further, the adhesiveness with the photoconductor layer 103 is weaker than that of the opposing surface layer 102a to which the gel state portion 108 is adhered. Therefore, even after the electrode layers 101 and 102 are separated, the gel state high viscosity gel ink gathering portion 108 formed under a high electric field by optical writing irradiation remains on the surface layer 102a side, and development can be performed.

A specific example will be shown below.

In the actual device configuration, the photoconductor layer 10
Materials used in No. 3 include metal-free phthalocyanine, vanadium phthalocyanine, titanoyl phthalocyanine, N. N'-diphenyl-N-N'-bis(3-methylphenyl)-1.1'-biphenyl-4.4'-diamine, N. N-tetraphenyl-3,3'-dimethylbenzidine, N-N-N'-N'-tetraphenyl-4
．． 4'-diacinostilbene, N・N・N'・N'-tetratolyl-4.4'-diaminostilbene, tris(
8-hydroxyquinolinol) aluminum, 3,4,
9,10 perylenetetracarboxylic, bisbenzimidazole, N/N-diphenyl-3,4,9,10-
Examples include perylenetetracarboxylic diimide. However, the materials used are not limited to these. The thickness of the photoconductor layer is 1 μm to 50 μm, preferably 10 to 30 μm. Specifically, the surface layer 102a is
A resin having a polar group, such as acrylic ester, hydroxyacrylic ester, etc., is formed on the second electrode layer 102 to a thickness of 5 to 50 μm. The distance between the photoconductor layer 103 and the surface layer 102a is 50 μm to 50 μm.
The voltage set in the range of 0 μm and the voltage applied to the interval is:
100v to 10Kv is considered appropriate. The colloidal developer 104 contains fine silica gel powder generally represented by SiO2.nH2O, [K.Mg.(AlSi3O10 )(O
H) 2] mica fine powder, (C6H10O5)n
Solid fine particles such as cellulose shown by are dispersed, and if necessary, carbon black, oil yellow AB,
A colloidal solution in which an inorganic or organic colorant such as Oil Red, Oil Blue G Extra, or Oil Black is dispersed or dissolved is used. The solid fine particles used here are 0.1 to 30% by weight, preferably 2 to 15% by weight.
Disperse it in a solvent. The particles also have a water content of 1 to 10% by weight.

The basic electrorheological process of the developer strongly depends on the polarization mechanism of the dielectric component of the particles themselves and the polarization mechanism of the electric double layer of the solvent around the particles.

FIG. 4 is a perspective view of a main part showing a specific example of the apparatus, and FIG. 5 is a partially enlarged view thereof. The surface layer 102a is formed by coating the drum-shaped second electrode layer 102 with a hydroxymethyl methacrylate resin layer to a thickness of about 10 μm. The second electrode layer and the photoconductor layer are formed by depositing an ITO transparent electrode on transparent PET 50 μm, then depositing 1 μm metal-free phthalocyanine on ITO as a CGR (charge generating layer), and then on top of that, CTL (charge generating layer). moving layer)
N-N-N'-N'-tetratolyl-4.4' diaminostilbene was dissolved in a solvent and coated to a thickness of about 30 μm, which was then used as the final photoreceptor belt. The distance between the photoconductor layer 103 and the surface layer 102a is approximately 20
It is set to 0 μm. During this time, from the developer supply tank 201,
A developer 104 in which 15 wt % of silica gel fine powder is added and dispersed in a 5 wt % dispersion of ISoper L (saturated hydrocarbon solvent: Exxon Chemical) of carbon black is uniformly spread on the photoconductor layer 103 . The intermediate transfer roll 100 including the surface layer 102a and the belt 200 on which the photoconductor layer 103 is formed are connected to the belt 2 at the transfer portion A where the distance is the shortest.
00 is a recess, and the developed developer accumulates in the recess. When a voltage of 1 Kv is applied to both electrode layers and in that state, the information to be written is irradiated onto the photoconductor layer 103 as pulsed light from a GaAs semiconductor laser 106 with a wavelength of 780 μm, the developer in the area irradiated with the laser light 204 becomes highly clayey, aggregates and adheres to the surface layer 102a side,
The ink aggregate 108 is taken out from the recess where the developer has accumulated and rotated, and comes into contact with the image receiving paper P supplied between the transfer roller 203 and the ink aggregate 108 is transferred from the intermediate transfer roller 100 to the image receiving paper P due to pressure. . After this belt 200
The remainder of the upper developer is washed away by a clean brush 202, and ink developer is again supplied from 201 to repeat the same transfer process. The thus obtained transfer material was a clear image with very clear dots and no background smudges. Note that the image receiving paper P is commonly called plain paper, such as XER.
OX4024, etc.

[0018]

According to the structure of the present invention, a photoconductor layer is provided on one of the two electrode layers, the electric field strength between the electrode layers is modulated by light, and the viscosity of the developer is controlled. Image deterioration caused by latent image deterioration that conventionally occurs during latent image formation has been eliminated, and a significant transfer improvement has been achieved. In addition, the irreversible ink aggregation mechanism removes factors that cause background stains, such as bleeding, that occur during transfer to image-receiving paper, resulting in a high-quality image.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the operation and basic device configuration of the present invention.

FIG. 2 is a diagram illustrating the operation and basic device configuration of the present invention.

FIG. 3 is a diagram illustrating the operation and basic device configuration of the present invention.

FIG. 4 is a perspective view illustrating a specific example of the device of the present invention.

FIG. 5 is an enlarged view of FIG. 4.

[Explanation of symbols]

101 First electrode layer 102 Second electrode layer 102a Surface layer 103 Photoconductor layer 104 Colloidal developer 105 Power supply 106 Light source

Claims (2)

[Claims] 1. An image forming method using a colloidal developer in which solid fine particles having dielectric properties are separated into an insulating solvent, the method comprising: a first electrode layer having a photoconductor layer;
A second surface layer is provided on the side opposite to the electrode layer with the photoconductor layer interposed therebetween, and has a surface layer formed thereon that has a stronger adhesive force than the photoconductor layer to the gel state portion of the developer. by supplying the colloidal developer between the first electrode layer and the second electrode layer, applying a voltage between the first electrode layer and the second electrode layer, and irradiating the photoconductor layer with light. The method is characterized in that an electrostatic latent image is formed on the irradiated portion, a colloidal developer on the electrostatic latent image is brought into a gel state, and a high-viscosity electrorheological fluid image is formed on the surface layer by this gel state portion. Image forming method. 2. An image forming apparatus using a colloidal developer in which dielectric solid particles are dispersed in an insulating solvent, the first electrode layer having a photoconductor layer;
The colloidal developer is provided on the side opposite to the electrode layer with the photoconductor layer in between, and the colloidal developer is supplied at a distance from the photoconductor layer to the gel state portion of the developer. a second electrode layer formed with a surface layer having strong adhesive strength;
An image forming apparatus comprising: a power source that applies a voltage between the first electrode layer and the second electrode layer; and a light source that irradiates the photoconductor layer with light.