JP2000305304A - Image forming method using ferroelectric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method using a ferroelectric in which electrification, image exposure and development can be carried out in a light room and can be written and erased at any time, an image can be formed as a color image, plural toner images can be formed when an image is written once, high mechanical strength is ensured, surface scuffing due to toner development is suppressed, any toner developing system may be adopted and printing on many sheets is suitably carried out. SOLUTION: In the first process, a ferroelectric element with a ferroelectric layer comprising an inorganic oxide ferroelectric and a heat-crosslinked and cured resin on an electrically conductive substrate is prepared and the electric dipoles of the ferroelectric in the ferroelectric layer are aligned in one direction. In the second process, the electric dipoles of a part corresponding to an image area or a non-image area are inverted. In the third process, the ferroelectric layer are uniformly heated to the Curie point or below and cooled to form an electrostatic latent image. In the fourth process, this electrostatic latent image is developed with a toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, and more particularly, to an image forming method of forming an electrostatic latent image using a ferroelectric substance and then visualizing the electrostatic latent image using toner. About the method.

[0002]

2. Description of the Related Art In general, an electrophotographic method, which is one of image forming methods used in copying machines and printers, charges a photosensitive member having a photosensitive layer composed of a photoconductor and then exposes the photosensitive member by image exposure. Form an electrostatic latent image on the photosensitive layer of the body, develop it with electrostatic toner, transfer the toner image on the photoconductor to film, plain paper, etc., and fix the transferred toner image To form a visible image. To form the same visible image again, the toner adhered to the photoconductor is cleaned, charged again, and the same steps such as image exposure, transfer, and fixing are repeated. Therefore, when a plurality of identical images are created, the copying speed is limited, and high-speed copying is difficult.

In order to solve this problem, "Photographic Science and Engineering (Ph.
otographic Science and Engineering ”Vol. 25 (1981)
Years) pp. 35-39 and 209-215 propose an electrophotographic photosensitive member having memory properties. According to this method, once image exposure is performed, a plurality of copies can be made by repeating the above-described steps from development to fixing.

However, the electrophotographic photoreceptor described in this document cannot store a latent image formed by image exposure for a long period of time, has a problem in memory, and cannot store it in a bright room. In addition, printing durability and environmental stability are poor, and they have not been put to practical use.

Also, a ferromagnetic material is used to form a latent image having memory properties according to the magnitude of its magnetic susceptibility, developed using a magnetic toner, transferred, fixed and transferred to a plurality of visible images by one image writing. Such as "Repro MG8000" (manufactured by Iwasaki Tsushinki), "Varipress M450" (Bull-Nipson)
Has been put to practical use.

Further, Japanese Patent Application Laid-Open No. Hei 5-221139 discloses that after an organic ferroelectric layer is subjected to a poling (dipole orientation) treatment, light is applied to write an image so that the exposed portion has a Curie point (Tc) or more. There has been proposed a recording method in which a latent image is formed by heating the latent image, the continuous copying is possible, and the latent image can be stored.

[0007]

As described above, the conventional electrophotographic method using a photoconductor is used in various fields such as a printer, a copying machine, and a direct plate making. Must be performed in a dark room,
Also, in order to create a plurality of identical images, the toner attached to the photoconductor is cleaned and then charged again, and then the same processes such as image exposure, transfer, and fixing are repeated. High-speed copying is difficult.

Further, in the method using a ferromagnetic material, a magnetic head is used as a writing head, so that the resolution is limited, and it is difficult to produce a color magnetic toner, so that a color image cannot be produced. There is a point.

Further, in writing an image using an organic ferroelectric substance, light is irradiated and the exposed portion is cured at the Curie point (T
c) In the method of forming a latent image by heating as described above, since the surface of the organic ferroelectric material has low mechanical strength, the surface is easily scratched by toner development or the like, and such a scratch causes the non-image area to be damaged. And the contamination of the non-image area increases as the number of printed sheets increases. For this reason, there are problems that the method of toner development is limited and that the method is not suitable for printing many sheets.

Usually, when producing ceramics, a binder resin and an inorganic powder are kneaded together with an extremely small amount of a solvent, and a solvent containing alcohol or water as a main component is added to the mixture to form a slurry, which is then subjected to a doctor blade method or a static method. In general, a method of forming into a predetermined shape by using a hydraulic pressure method, drying a solvent, and then sintering in an electric furnace, a gas furnace, or the like.

The binder resin has many hydrophilic groups such as a hydroxyl group and a carboxyl group. Inorganic oxide is hydrophilic, by using a highly hydrophilic binder,
It is possible to increase the volume content of the inorganic oxide powder in the mixture of the binder resin and the inorganic oxide powder.

In manufacturing the ferroelectric element of the present invention, by using a hydrophilic binder resin, it is possible to increase the volume fraction of the ferroelectric powder in the ferroelectric element, and to reduce the It is very useful for obtaining a high-contrast electrostatic latent image required in such a case.

However, since such a resin is a thermoplastic resin in which emphasis is placed on dispersibility and moldability, when such a resin is used in a state where an inorganic ferroelectric is dispersed without sintering as in the present invention. There has been a demand for a method for producing an element having further improved surface hardness and heat resistance.

Problems to be solved by the present invention are charging,
Image exposure and development can be performed in a bright room,
Colorization of images is possible, charging, image exposure, writing and erasing of images at any time are possible, it is possible to create multiple sheets of the same toner image with one image writing, and further mechanically An object of the present invention is to provide an image forming method using a ferroelectric material, which has high strength, is hardly scratched on the surface by toner development or the like, does not limit the method of toner development, and is suitable for printing many sheets.

[0015]

Means for Solving the Problems As a result of intensive studies, the present inventors have developed a method of forming a latent image using an inorganic oxide ferroelectric and forming a toner image by electrophotography. And completed the present invention.

That is, according to the present invention, there is provided (1) a ferroelectric element in a ferroelectric element having a ferroelectric layer comprising an inorganic oxide ferroelectric and a resin on a conductive support. A first step of arranging the ferroelectric dipoles in the body layer in one direction, (2) a second step of inverting dipoles in a portion corresponding to an image portion or a non-image portion, and (3) a ferroelectric layer A third step of uniformly heating to below the Curie point and then cooling to develop an electrostatic latent image, and (4) a fourth step of developing the electrostatic latent image with toner The present invention provides an image forming method, wherein the resin used for the ferroelectric layer is a thermo-crosslinking cured resin.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A ferroelectric element used in an image forming method of the present invention comprises a ferroelectric layer and a conductive support layer. As shown in FIG. The support layer may be in a close contact state, or an intermediate layer may be provided between the ferroelectric layer and the support layer. Further, a film for protecting the ferroelectric may be provided on the upper layer of the ferroelectric layer.

The inorganic oxide ferroelectric used for the ferroelectric layer may be capable of reversing the dipole orientation and the dipole in the image area or the non-image area by corona charging, etc. , Which decrease when the temperature is raised from room temperature.
Further, as these inorganic oxide ferroelectrics, perovskite-type crystals such as barium titanate and PZT (lead zirconate titanate) are well known. In the present invention, those having a layered structure are preferable. Bismuth layered compounds are particularly preferred. These inorganic oxide ferroelectrics can be used alone or in combination of two or more. As such an inorganic oxide ferroelectric, for example, the general formula (1)

[(Bi ₂ O ₂ ) ²⁺ (XY ₂ O ₇ ) ^2- ]

[Wherein X is Sr, Pb or Na _0.5 B
i represents _0.5 , and Y represents Ta or Nb. An inorganic ferroelectric oxide represented by the general formula (2):

[0021] _{[X n Bi 4 Ti n +} 3 O 3n + 12]

Wherein X is Sr, Ba, Pb or Na
_0.5 represents Bi _0.5 , and n represents 1 or 2. And the like. More specifically, SrBi ₂ Ta ₂ O ₉ , SrBi ₂ Nb
₂ O ₉ , SrBi ₄ Ti ₄ O ₁₅ , and the like.

The ferroelectric element used in the method of the present invention uses a thermo-crosslinkable resin as a resin for the ferroelectric layer.
The surface hardness and heat resistance of the element are further improved.

The thermosetting resin used in the present invention is a thermosetting resin, a thermosetting agent or a thermosetting agent, and, if necessary, a thermosetting resin using a catalyst.

Examples of the thermosetting resin include polyvinyl alcohol resin, polyvinyl butyral resin, polyacetal resin, acrylic polyol resin, polyester resin, epoxy resin, alkyd resin, and polyamic acid resin. From the viewpoint of powder dispersibility, a polyvinyl butyral resin, an acrylic polyol resin, and an epoxy resin are preferable, and an epoxy resin and a polyvinyl butyral resin are more preferable. Since the above-mentioned thermosetting resin has a hydroxyl group, a carboxyl group, and an amino group, it can be cross-linked and cured by adding an appropriate curing agent. In the present invention, commercially available products of these resins can be used without any particular limitation.

Commercially available polyvinyl butyral resins include, for example, BL-1, BL-2, BL-3, BL-S, BM- of "ESREC" B series manufactured by Sekisui Chemical Co., Ltd.
1, BM-5, BM-2, BM-S, BH-3, BH-
S, BX-1, BX-2, BX-5, BX-55, and the like.

Commercially available polyacetal resins include KS-5 manufactured by Sekisui Chemical Co., Ltd.

Commercially available acrylic polyol resins include, for example, "Acridic" series manufactured by Dainippon Ink and Chemicals, Inc.

Commercially available polyester resins include, for example, "Byron" series manufactured by Toyobo.

Commercially available epoxy resins include, for example,
"Epiclon" series manufactured by Dainippon Ink and Chemicals, Inc .; "Epicoat" series manufactured by Shell Co., Ltd .;

Commercially available alkyd resins include, for example, "Veccosol" series and "Super Veccosol" series manufactured by Dainippon Ink and Chemicals, Inc.

Examples of the curing agent include acid anhydride, melamine resin, polyisocyanate resin, phenol resin, benzoguanamine resin and the like. Acid anhydrides are suitably used for curing epoxy resins, and melamine resins and polyisocyanate resins are used for curing resins having hydroxyl groups such as acrylic polyols and polyvinyl butyral resins. Acid anhydrides and melamine resins can be particularly preferably used. Among these curing agents, those subjected to a deionization treatment are particularly preferable.

Commercially available melamine resins include, for example,
Dainippon Ink and Chemicals, Inc.'s butylated melamine resin "Super Beckamine" series, Mitsui Cytec's "Symel" series, Sumitomo Chemical's "Sumimar" series, Sanwa Chemical's Nicaraq "series.

Commercially available benzoguanamine resins include:
For example, "My Coat" series manufactured by Mitsui Cytec Co., Ltd. and the like can be mentioned.

Commercial products of the polyisocyanate resin include, for example, "Barnock" series manufactured by Dainippon Ink and Chemicals, Inc. and the like.

Commercially available phenolic resins include, for example, "Beckasite" series and "Super Beckasite" series manufactured by Dainippon Ink and Chemicals, Inc.

Examples of the acid anhydride include the "Epiclon" series manufactured by Dainippon Ink and Chemicals, maleic anhydride, succinic anhydride, and phthalic anhydride.

A catalyst can be used in combination to rapidly carry out the crosslinking curing reaction. Examples of the catalyst used for such a purpose include tertiary amines, carboxylic acids, sulfonic acids, metal alkoxides, and the like. However, it is better to refrain from using acids and bases as much as possible, because the electrical resistance of the resulting thermally crosslinked cured resin decreases.
It is particularly preferred not to use a catalyst.

It is desirable that the thermosetting resin has a hydrophilic functional group such as a hydroxyl group, a carboxyl group, or an amino group in a side chain. Those having a hydroxyl group and a carboxyl group in the side chain are more desirable, and those having a hydroxyl group in the side chain are particularly preferred.

The hydroxyl equivalent of the thermosetting resin is 50 to 10
The range of 00 is preferable, the range of 50 to 400 is more preferable, the range of 100 to 300 is particularly preferable, and the range of 150 to
A range of 270 is particularly preferred.

In order not to release unnecessary hydroxyl groups or carboxyl groups in the thermosetting resin, for example, the necessary hydroxyl group equivalents of the thermosetting resin and the functional groups of the curing agent are determined based on the hydroxyl equivalents and epoxy equivalents, and the hydroxyl equivalents and melamine equivalents. It is preferable to calculate and determine the equivalent.

To improve the surface smoothness of the device, a leveling agent can be used in the heat-crosslinking cured resin. However, an ionic leveling agent is not suitable because it lowers the electric resistance. Are preferred.

Commercially available fluorine-based leveling agents include, for example, the "Megafac" series manufactured by Dainippon Ink and Chemicals, Inc.

In order to improve the moldability of the device, a dispersant may be used in the heat-crosslinking curable resin. However, an ionic dispersant reduces electric resistance and is not suitable. Are preferred.

Commercially available silane coupling agents include:
For example, Shin-Etsu Silicone's KBM series, KBE
Series, KA series, KBC series, and the like.

When a thermally crosslinked cured resin having low volume resistance at room temperature is used for the ferroelectric layer, a first step of arranging the dipoles of the ferroelectric in one direction and a portion corresponding to an image portion or a non-image portion In the second step of inverting the dipole, when the dipole is oriented using, for example, corona charging or the like, the corona is not sufficiently charged, and the orientation of the dipole becomes hard to occur. The degree of orientation deteriorates. Also, in the inversion of the dipole in the second step, the same occurs, so that the degree of orientation of the dipole to be inverted deteriorates, which is not preferable.

If the orientation of the dipoles in the ferroelectric layer is not sufficient, the surface potential generated by the change in the electric resistance of the ferroelectric layer and the pyroelectricity of the ferroelectric material is reduced, and the contrast of the surface potential is reduced. Becomes insufficient. If the contrast of the surface potential is not sufficient, the toner tends to adhere to the non-image area when forming the toner image, and the toner hardly adheres to the image area, and the quality of the toner image deteriorates. Would.

The conductive support layer is not particularly limited as long as it has necessary mechanical strength and smoothness and has conductivity, and the material is not particularly limited. In terms of stability, etc., metals such as platinum, aluminum, nickel, and copper, conductive polymers and carbon black,
A conductive inorganic material such as ITO is preferable, and a material obtained by laminating a conductive film on plastic, paper, or another insulating substrate may be used.

The ferroelectric element used in the image forming method of the present invention includes, for example, (A) a method of forming a ferroelectric layer on a conductive support layer, and (B) a ferroelectric layer and a conductive support. It can be manufactured by a method in which the body layers are separately manufactured and then bonded.

As the method (A), a ferroelectric material, a resin and a solvent are mixed and dissolved, and the resulting mixed solution is dipped, bar-coated, roll-coated, spray-coated, spin-coated, and doctor-coated. A method of forming a ferroelectric layer by removing the solvent after coating on a substrate by a blade method, etc., using the mixed solution used above, forming a ferroelectric layer by film deposition by an electrodeposition method. And a method of producing a ferroelectric layer having improved surface hardness and heat resistance by crosslinking these formed films by heat.

As the method (B), a ferroelectric material, a thermosetting resin, a curing agent and a solvent are mixed and dispersed, and this mixed solution is subjected to a dipping method, a bar coating method, a roll coating method, a spray coating method. , Spin coat method, doctor blade method, after applying, remove the solvent,
A method of producing a ferroelectric film by thermosetting to form a film and then bringing the ferroelectric film into close contact with a support layer using an adhesive having conductivity, and the like.

The solvent used in the mixed solution for forming the ferroelectric layer is a solvent that does not deteriorate the inorganic oxide ferroelectric substance and is a solvent that can dissolve or disperse the thermosetting resin and the curing agent. It is necessary that the solvent does not react with the thermosetting resin or the curing agent. A solvent satisfying such conditions may be selected from the following examples and used. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol and butanol; cellosolves such as ethyl cellosolve, methyl cellosolve and butyl cellosolve. Solvents: amide solvents such as dimethylformamide and methylpyrrolidone; dichloromethane,
Chlorine solvents such as 1,2-dichloroethane and 1,1,2-trichloroethylene; and aromatic non-polar solvents such as toluene, xylene and mesitylene. Further, the above-mentioned solvents can be mixed and used at an appropriate ratio.

In particular, at present, which is sensitive to environmental problems, it is very preferable to use an aqueous solvent. Therefore, a water-containing mixed solvent system can be used as long as it does not react with a thermosetting resin or a curing agent.

The thickness of the ferroelectric layer is such that a dipole is oriented by applying an electric field. If the thickness is too large, a high charging voltage is required or charging tends to be required repeatedly. So it ’s not desirable,
On the other hand, if it is too thin, the difference between the surface potential of the image area and the surface potential of the non-image area becomes small, and the contrast of the visible image with the toner tends to decrease.
The range of m is preferred, the range of 10 μm to 200 μm is more preferred, and the range of 15 μm to 100 μm is particularly preferred.

The method of arranging the ferroelectric dipoles in the ferroelectric layer in one direction in the first step of the image forming method of the present invention (hereinafter referred to as dipole alignment treatment) is based on corona charging. A charging method used in electrophotography such as a method and a method using a roller electrode can be used.

The dipole alignment treatment by corona charging can be performed using a corona charger of a usual corotron type or scorotron type. Further, the dipole orientation treatment by roller charging is performed by bringing a conductive rubber roller to which a high voltage is applied into contact with a dielectric layer, for example, having a resistance value of 10 5 to 1.
A method in which a voltage of several hundred volts or more is applied to a conductive rubber roller having a resistance of about 09 Ωcm to charge, a resistance value of 10 3 to 10 5 Ω
There is a method of attaching a fibrous wire rod having a thickness of cm to the surface of the conductive roller in a brush shape to enhance the contact property, and applying a high voltage to the conductive roller to charge the conductive roller. In both cases, a suitable method may be selected according to the system configuration of the apparatus.

The time required for dipole alignment is corona voltage,
It depends on the applied voltage of the roller electrode or its shape, and can be appropriately set according to the system configuration of the apparatus, the method of use of the apparatus, or the application.

In the second step of the image forming method of the present invention, the method of inverting the dipole of the portion corresponding to the image portion or the non-image portion is as follows. A method of inverting a dipole, a method of inverting a dipole corresponding to an image portion or a non-image portion using a stylus head, a method of inverting a dipole of an image portion or a non-image portion by ion flow, and the like. Is mentioned.

When the volume resistivity of the ferroelectric material is small, for example, 10 10 Ωcm, the electric field of the corona is not sufficiently applied, and the orientation of the dipole and the reversal of the dipole in the image portion or the non-image portion are caused by Since the writing is not performed sufficiently, there is a tendency that image writing cannot be performed satisfactorily. Therefore, it is preferable that the volume electric resistivity of the ferroelectric material is large.

When the relative dielectric constant of the ferroelectric substance is large, for example, 1000 or more, since the capacitance is large, an electrostatic contrast sufficient for toner development can be obtained with a film thickness of about 100 μm. Because they tend not to be
The relative permittivity of the ferroelectric material is preferably small.

The capacitance of the ferroelectric layer can be reduced by increasing the film thickness. However, an increase in corona voltage required for dipole orientation and the like, and an increase in energy required during heating and cooling. It is not preferable to increase the film thickness, since it tends to increase remarkably.

In order to generate a surface potential difference between the written latent image portion and the non-image portion, the third method of the present invention for forming an image is carried out.
In the process, the ferroelectric layer in which the dipole of the portion corresponding to the image portion or the non-image portion is inverted is heated below the ferroelectric-paraelectric phase transition point (Curie point) of the dielectric, and then cooled. To develop an electrostatic latent image. It is indispensable that the ferroelectric material has ferroelectricity at room temperature, and since the orientation of the dipole of the ferroelectric material is found to be beyond the Curie point, from the viewpoint of stability of image information, the heating temperature is It is necessary to keep it below the Curie point.

By heating the ferroelectric layer to a temperature below the Curie point, the spontaneous polarization of the ferroelectric decreases, the bound surface charges become free charges, and in the heated state, the ferroelectric layer This free charge leaks because the electrical resistance is low.

By cooling from the heated state, the spontaneous polarization reversibly returns to its original size, but the leaked surface charge is irreversible, so that a potential is generated due to the spontaneous polarization. Therefore, the electric resistance of the ferroelectric layer needs to be reduced by increasing the temperature from room temperature.

A device that heats the ferroelectric layer, whose temperature immediately drops after heating, is suitable. In the case of a device in which a heating element such as a heat roll contacts the ferroelectric substance and performs heating, a heating element is used. The smaller the heat capacity, the better.

Further, as a means for heating the ferroelectric, a method of irradiating light or the like and converting the energy into heat can be used. The method of irradiating light is particularly preferable in that the method is non-contact and the temperature is lowered immediately after heating.

The light source of the light irradiation device includes, for example, an infrared lamp, a halogen lamp, a xenon lamp, a metal halide lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a laser and the like.

In the method of heating by irradiating light, the light irradiation time and irradiation intensity require a certain intensity or more, but the emission wavelength of the light source, the absorption wavelength of the light absorbing material,
Since the optimum value of the light intensity to be irradiated varies depending on conditions such as the heat capacity of the ferroelectric element, it is necessary to select appropriate conditions as appropriate. That is, an appropriate value may be selected for the intensity of the irradiated light depending on conditions such as the emission wavelength, the absorption wavelength of the light absorbing substance, and the heat capacity of the ferroelectric element.

Further, it is effective to uniformly irradiate the ferroelectric layer temporally and planarly in order to uniformly heat the inside of the ferroelectric layer.

In the fourth step of the image forming method of the present invention,
After forming an electrostatic latent image, at a temperature showing ferroelectricity,
The latent image is developed into a visible image by developing using an electrostatic powder toner or a liquid toner.

As the electrostatic powder toner and the liquid toner, appropriate ones may be selected from commercial products.

The toner image developed on the surface of the ferroelectric layer is transferred to the plain paper or film electrostatically by charging the plain paper or the back of the film after the plain paper or film is overlaid. After that, fixing may be performed.

In order to continuously produce a plurality of identical images, if the surface of the ferroelectric layer has a surface potential contrast that allows electrostatic toner development, the electrostatic toner development, transfer, and fixing are successively performed. Just do it.

If the surface potential contrast or the like is reduced due to the transfer conditions or the surrounding environment, the surface potential contrast is formed by heating and cooling the ferroelectric layer, if necessary, and then the toner development is performed. Then, transfer and fixing may be performed.

[0075]

The present invention will be described in more detail with reference to the following examples. However, the invention is not limited to these examples.

Example 1 Strontium carbonate (SrC)
O ₃₎ 12.00 g, titanium oxide (TiO ₂₎ 25.9
After thoroughly mixing 7 g and bismuth trioxide (Bi ₂ O ₃ ) 75.75 g, the mixture was kept at 1000 ° C. for 3 hours in an electric furnace. The sintered mixture was pulverized using a mortar to obtain powdery SrBi ₄ Ti ₄ O ₁₅ .

5 g of the powder of SrBi ₄ Ti ₄ O ₁₅ thus obtained was mixed with 19.6 parts by weight of “Epiclon HM-101” (an epoxy resin manufactured by Dainippon Ink and Chemicals, Inc.)
"Nikarac MW-30" (melamine resin manufactured by Sanwa Chemical Co., Ltd.) 0.4 parts by weight, 5 g of a resin solution composed of 40 parts by weight of cyclohexanone and 40 parts by weight of toluene were mixed with a planetary-type fine-particle mill "PULVERISETTE 7". "
(FRITSCH) and dispersed and mixed.

The dispersion mixture thus obtained was applied on a copper substrate using a bar coater so that the film thickness after drying was about 25 μm, followed by heating and curing at 200 ° C. for 20 minutes. Then, a ferroelectric element was obtained by forming a ferroelectric layer. The surface hardness of this element was 2H.

This ferroelectric element has a pulse width of 0.2
The alignment treatment was performed by applying a negative corona pulse having a voltage of 6 kV for 100 times per second.

Through an arbitrary mask, a pulse width of 0.2
By applying a positive corona pulse having a voltage of 6 kV for 100 times per second, the polarization was inverted only in the portion corresponding to the image portion.

Next, the ferroelectric element was heated to 150 ° C. using a heater, and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner having a positive polarity, the toner adhered to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a first arbitrary image.

Further, the ferroelectric element after the visible image has been transferred to plain paper is heated and cooled, and development, transfer and fixing are repeatedly performed in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be formed. Image was obtained.

After storing the ferroelectric element in a bright room for one month, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the thus treated ferroelectric element using the powder toner of the positive electrode, the toner adhered only to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a similar image.

After the visible image is transferred to plain paper, the ferroelectric element is heated, then cooled, and development, transfer, and fixing are repeated in the same manner as in the first sheet to obtain a plurality of arbitrary images. I got

Further, the ferroelectric element was subjected to an alignment treatment by applying a negative corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times. By applying a positive corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times through an arbitrary mask, the polarization was inverted only in the portion corresponding to the image area. Next, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner of positive polarity, the toner adhered only to the portion where the polarization was inverted. This toner image is transferred to plain paper and fixed,
The second arbitrary image was obtained.

Further, the ferroelectric element after the visible image has been transferred to plain paper is heated and cooled, and development, transfer and fixing are repeatedly performed in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be obtained. Image was obtained.

(Comparative Example 1) SrBi ₄ T obtained in Example 1
5 g of i ₄ O ₁₅ powder and “Epiclon HM-101”
(Epoxy resin manufactured by Dainippon Ink), 5 g of a resin solution consisting of 20 parts by weight of cyclohexanone and 40 parts by weight of toluene were mixed with a planetary-type fine-particle mill “PULVERISETTE 7” (manufactured by FRITSCH). )
Was dispersed and mixed.

The dispersion mixture thus obtained was applied on an aluminum substrate using a bar coater so that the film thickness after drying was about 25 μm.
By heating and curing for 0 minutes to form a ferroelectric layer, a ferroelectric element was obtained. The surface hardness of this element was F.

The device of Comparative Example 1 had a lower surface hardness than that of the device of Example 1, and the printing durability of the device was inferior. It became clear that the printing durability was improved by using a thermosetting resin.

Example 2 SrBi ₄ T obtained in Example 1
powder 5g of i ₄ O _15, "BH-S" (manufactured by Sekisui Chemical Co., Ltd. of hydroxyl equivalent weight of about 220 of the polyvinyl butyral) 10 parts by weight, "NIKALAC MW-30" (Sanwa Chemical Co., Ltd. Melamine resin) 10 weight Parts, xylene and 60 parts by weight of xylene and 20 parts by weight of butyl cellosolve are mixed with 5 g of a resin solution, and a planetary-type fine-milling machine “PULVERISETTE 7” is used.
(FRITSCH) and dispersed and mixed.

The dispersion mixture thus obtained was applied on a copper substrate using a bar coater so that the film thickness after drying was about 25 μm, and then heated and cured at 180 ° C. for 30 minutes. Then, a ferroelectric element was obtained by forming a ferroelectric layer. The surface hardness of the element thus obtained was H.

The pulse width of the ferroelectric element is 0.2
The alignment treatment was performed by applying a negative corona pulse having a voltage of 6 kV for 100 times per second.

Through an arbitrary mask, a pulse width of 0.2
By applying a positive corona pulse having a voltage of 6 kV for 100 times per second, the polarization was inverted only in the portion corresponding to the image portion.

Next, the ferroelectric element was heated to 150 ° C. using a heater, and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner having a positive polarity, the toner adhered to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a first arbitrary image.

Further, after the visible image is transferred to plain paper, the ferroelectric element is heated and cooled, and development, transfer and fixing are repeated in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be obtained. Image was obtained.

After storing this ferroelectric element in a bright room for one month, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the thus treated ferroelectric element using the powder toner of the positive electrode, the toner adhered only to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a similar image.

After the visible image has been transferred to the plain paper, the ferroelectric element is heated, cooled, and repeatedly subjected to development, transfer and fixing in the same manner as the first sheet to obtain a plurality of arbitrary images. I got

Further, the ferroelectric element was subjected to an alignment treatment by applying a negative corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times. By applying a positive corona pulse having a pulse width of 0.2 seconds and a voltage of 6 kV 100 times through an arbitrary mask, the polarization was inverted only in the portion corresponding to the image area. Next, the ferroelectric element was heated to 150 ° C. using a heater and then cooled to form an electrostatic latent image. When the electrostatic latent image was visualized on the ferroelectric element treated in this manner using a powder toner of positive polarity, the toner adhered only to the portion where the polarization was inverted. This toner image is transferred to plain paper and fixed,
The second arbitrary image was obtained.

Further, the ferroelectric element after the visible image has been transferred to the plain paper is heated and cooled, and development, transfer and fixing are repeatedly performed in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be obtained. Image was obtained.

(Comparative Example 2) SrBi ₄ T obtained in Example 1
powder 5g of i ₄ O _15, "BH-S" (manufactured by Sekisui Chemical Co., Ltd. of polyvinyl butyral) 5 parts by weight, consists of 70 parts by weight of butyl cellosolve 25 parts by weight of xylene resin solution 5g
, Planetary-type fine-grain pulverizer "PULVERISETT
E) 7 "(manufactured by FRITSCH).

The dispersion mixture thus obtained was applied on an aluminum substrate using a bar coater so that the film thickness after drying was about 25 μm.
By heating and curing for 0 minutes to form a ferroelectric layer, a ferroelectric element was obtained. The element thus obtained had a surface hardness of B.

The device of Comparative Example 2 had a lower surface hardness than the device of Example 2 and was inferior in printing durability. It became clear that the printing durability was improved by using the thermosetting resin.

Example 3 SrBi ₄ T obtained in Example 1
5 g of i ₄ O ₁₅ powder, 4 parts by weight of “BH-3” (polyvinyl butyral having a hydroxyl equivalent of about 180, manufactured by Sekisui Chemical Co., Ltd.), and “BL-1” (hydroxyl equivalent of about 180, manufactured by Sekisui Chemical Co., Ltd.)
Of polyvinyl butyral) 4 parts by weight,
-30 "(Melamine resin manufactured by Sanwa Chemical Co., Ltd.), 3 parts by weight, p-toluenesulfonic acid 0.05 part by weight, xylene 30 parts by weight, butyl cellosolve 30 parts by weight, and ethyl cellosolve 30 parts by weight 12 g of a resin solution. , Planetary-type pulverizer “PULVERISETTE 7”
(FRITSCH) and dispersed and mixed.

The dispersion mixture thus obtained was applied on a copper substrate using a bar coater so that the film thickness after drying was about 20 μm, and then heated and cured at 150 ° C. for 15 minutes. Then, a ferroelectric element was obtained by forming a ferroelectric layer. The element thus obtained had a surface hardness of 2H. By using a strong acid catalyst such as p-toluenesulfonic acid in combination, it was possible to lower the thermosetting temperature, shorten the thermosetting time, and produce an element having a high surface hardness.

The pulse width of this ferroelectric element is 0.2
The alignment treatment was performed by applying a negative corona pulse having a voltage of 6 kV for 100 times per second. Using this ferroelectric element, orientation processing, writing of a latent image, formation of an electrostatic latent image, development, transfer and fixing are performed in the same manner as in Example 1.
The second arbitrary image was obtained.

Further, the ferroelectric element after the visible image was transferred to plain paper was heated and then cooled, and the same as in the first sheet,
Developing, transferring and fixing were repeated to obtain a plurality of arbitrary images.

After storing this ferroelectric element in a light room for one month, it was heated and cooled to 150 ° C. in the same manner as in Example 1 to form an electrostatic latent image, When the electrostatic latent image was visualized using the toner, the toner adhered only to the portion where the polarization was inverted. This toner image was transferred to plain paper and fixed to obtain a similar image.

After the visible image is transferred to plain paper, the ferroelectric element is heated, then cooled, and the development, transfer and fixing are repeated in the same manner as in the first sheet to obtain a plurality of arbitrary images. I got

Further, in the same manner as in the first embodiment, an orientation process, polarization reversal of the image portion, heating and cooling were performed on this ferroelectric element to form an electrostatic latent image, and the electrostatic latent image was visualized. Then, the toner image was transferred to plain paper and fixed to obtain a first arbitrary image.

Further, the ferroelectric element after the visible image has been transferred to plain paper is heated and cooled, and development, transfer and fixing are repeated in the same manner as in the first sheet, whereby a plurality of arbitrary sheets can be formed. Image was obtained.

[0111]

According to the image forming method using the ferroelectric element of the present invention, the latent image can be stably stored in a bright room for a long period, and the image can be written and erased as needed. Further, according to the image forming method using the ferroelectric element of the present invention, the contrast of the surface potential at the time of toner development is high, and the printing durability is excellent. It is possible to form a high quality toner image.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ferroelectric element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferroelectric layer 2 Ferroelectric 3 Resin 4 Support layer

Claims (6)

[Claims] (1) In a ferroelectric element having a ferroelectric layer made of an inorganic oxide ferroelectric and a resin on a conductive support, a ferroelectric dipole in the ferroelectric layer is removed. A first step of arranging in one direction, (2) a second step of inverting a dipole in a portion corresponding to an image portion or a non-image portion, and (3) after uniformly heating the ferroelectric layer below the Curie point. And (4) a fourth step of developing the electrostatic latent image with toner using a toner, wherein the resin used for the ferroelectric layer is heated. An image forming method, which is a cross-linked cured resin. 2. The image forming method according to claim 1, wherein the ferroelectric layer has a structure in which an inorganic oxide ferroelectric is dispersed in a resin. 3. The image forming method according to claim 1, wherein the thermosetting resin comprises a thermosetting resin and a thermosetting agent or a thermosetting agent. 4. The image forming method according to claim 3, wherein the thermosetting resin has a hydroxyl group, a carboxyl group or an amino group. 5. The image forming method according to claim 3, wherein the thermosetting resin has a hydroxyl group. 6. The image forming method according to claim 5, wherein the hydroxyl group equivalent of the thermosetting resin having a hydroxyl group is in the range of 50 to 400.