JPS60211465A - Electrostatic color recording method - Google Patents

Abstract

PURPOSE:To prevent fogging on the image part and staining on the background part by forming a conductive layer, and a dielectric layer contg. an insulating resin and a photoconductive zinc oxide in a weight ratio of (0.5-2.5):1 in succession. CONSTITUTION:A latent image is formed in the dark with an electrostatic recording head on the dielectric layer obtained by dispersing 0.5-2.5pts.wt. of photoconductive zinc oxide into 1pt.wt. of a dielectric resin and this dielectric layer is formed on a substrate enhanced in conductivity by coating to obtain an electrostatic recording body. A color image is obtained by repeating a developing step using a color toner. As the dielectric resin to be used for the dielectric layer, acrylic, vinyl acetate, silicone resins, etc. are enumerated. As the zinc oxide to be used for the photoconductor, a general electrophotographic type of zinc oxide can be used, and it is preferable to use the one sensitized with a dye in the visible light region of 400-700nm.

Description

Detailed Description of the Invention Technical Field The present invention relates to an electrostatic recording method for obtaining a single recorded image on an electrostatic recording medium (dielectric N layer) using a single-sided or double-sided controlled multi-stylus electrostatic recording head. Regarding.

(1 Flame 1) Conventionally, the following methods have been implemented or proposed as methods for obtaining the color display on a CRT as a color hard copy from the output section of a facsimile receiver, CAD plotter, or printer of various types of converters. It has been done.

1) Inkjet 2) Laser printer 3) Heat-sensitive melt transfer 4) Pen plotter 5) Heat-sensitive sublimation transfer 6) Melt-sublimation transfer 7) Heat-sensitive transfer reaction method Each of these methods has the following drawbacks. .

b) Printing takes a long time.

Among the above methods: 1), 3), 4), 5)) Running costs are high.

When using a line type thermal head in 3) and 5) above, c) There are multiple 911 devices, which are expensive, large and require maintenance.

In the case of 1) and 2) above.

2) After printing, transfer color sheets 1 to h5 are produced as by-products. In the case of 3), 5), [i), and 7) above.

e) Tone reproducibility is poor. ”-In the case of notes 1), 3), and 4).

Also, in electrostatic recording method, when creating a color image,
Methods for removing static electricity (potential) remaining on the dielectric layer after development include electrical static neutralization methods such as AC corona discharge, reverse polarity corona discharge, and application of reverse polarity voltage using a contact electrode. In either case, it is not possible to uniformly bring the entire surface of the dielectric layer to the potential O. Moreover, even if it were possible, it would require a long time. That is, since the dielectric layer is charged to either polarity due to its nature, it is impossible to uniformly bring the entire surface to the potential O using these electrical charge removal methods. Usually, residual potential remains, or the dielectric layer is charged with opposite polarity, or both polarities are unevenly distributed in some areas, resulting in striped or patchy charging. It is extremely difficult to uniformly bring the entire surface to a potential of O.

Furthermore, in the optical static elimination method, the dielectric layer is subjected to fatigue due to pre-exposure, which makes it difficult to build up a surface potential during the next latent image formation.

In recent years, as the use of computers has progressed in various fields, there has been an increasing demand for recording processed information, data, images, figures, etc. as color hard copies, and various methods have been tried, but each has the problems described above. be.

Recently, there has been a desire to develop an electrostatic recording method that can be used as a CAD plotter to obtain color images in a short time.

In the conventional multi-color electrostatic recording method,
- The surface potential (latent image) of the image area formed on the recording medium is completely canceled out during the development process, and the residual potential is more than 50%. remain.

Furthermore, non-image areas of the recording medium are also charged to a certain potential due to friction, pressure, or other factors during the latent image formation and development process. In this case, the second and subsequent development step 11) has the disadvantage that the latent image in the image area before fading is developed due to the residual potential, or it appears as dirt in the non-image area.

Purpose This invention provides a color image that can be obtained without developing fog in the previous image area or background smearing in the non-image area during second and subsequent development. It is an electrostatic recording method.

-F]- In particular, this invention forms a first electrostatic latent image in the dark with a multi-stylus electrostatic recording head on an electrostatic recording medium in which a conductive layer and a dielectric layer are sequentially provided on a support, and color toner is It is an object of the present invention to provide a color electrostatic recording method in which an electrostatic latent image remaining on a dielectric layer can be removed by light after development is performed.

Structure The structure of the present invention is to form a latent image in the dark with an electrostatic recording head on an electrostatic recording medium in which a conductive layer and a dielectric layer are sequentially provided on a support, and then repeat the development process with color toner to form a color image. In the color electrostatic recording method to obtain
: The dielectric layer of the electrostatic recording medium is insulating resin and photoconductive t! IB
! A color electrostatic recording method containing zinc I oxide in a weight ratio of 1:0.5 to 1:2.5, wherein the photoconductive zinc oxide further increases the dye in the visible light region of 400 to 700 nm. In addition, there is a method 1j in which the development process with color toner is repeated 6 times, and after the development is completed, a photohead annotation 1 is made on the entire surface of the lightning dielectric layer, and then the next latent image is formed. This method includes a method in which the above-mentioned light beam directed over the entire surface of the dielectric layer emits ultraviolet rays having a wavelength of 400 nm or less.

The structure of the 11L electrostatic recording material that can be photostatically eliminated for use in the IJ method of this invention is to have an S conductive layer on the support 1-+J1, if necessary, a conductive layer on the back side, and a low-resistance conductive layer in the support. Impregnated with a substance, it is used in conventional electrostatic recording media.
A dielectric layer in which photoconductive zinc oxide is dispersed at a ratio of 0.5 to 2.5 small openings is coated on a substrate that has been subjected to so-called conductive processing. This photoconductive zinc oxide is dye-sensitized in the visible light region. J
:D, when performing photostatic charge removal, the light irradiated to the dielectric layer is 400n.
Defrosting is carried out by irradiating light that is filtered with a filter etc. so that it does not contain ultraviolet rays of less than 200 m, and excludes the inherent absorption light of zinc oxide. J: Reduces pre-exposure fatigue and facilitates latent image formation in the next step.

The insulating resin used in the lightning dielectric layer includes resins used in dielectric layers of conventional electrostatic recording materials, and acrylic resins which are binder resins used in zinc oxide photosensitive layers for electrophotography. One or a mixture of two or more dielectric resins such as methacrylic resin, vinyl acetate resin, silicone resin, vinyl acetate-vinyl chloride copolymer resin, polyester resin, polyvinyl butyral resin, and styrene resin can be used.

As the optical dielectric zinc oxide, a general zinc oxide for electrophotography manufactured by a French method is used.

As a sensitizer for this zinc oxide, fluoreracene (FL
), Rose Bengal (RB), Thymol Blue (TB),
Tetrabromophenol blue (TBPB), phenol blue (PB), bromophenol blue (BPB)
Conventional electrophotographic paper (electrofax) dye sensitizers can be used.

This dielectric layer phase separation can be used as a lightning dielectric layer by a conventional dispersion method.

If necessary, auxiliary agents such as calcium carbonate, silica, clay, titanium oxide, fluorescent dyes, dispersants, antifoaming agents, etc. can be used in combination with the dielectric layer material. In general, the thickness of the lightning dielectric layer is suitably 3 to 15 .mu.m, preferably 4 to 10 .mu.m, in view of chargeability, withstand voltage, and dielectric constant.

The electrostatic recording material of this invention, as explained above, can obtain charging characteristics similar to those of conventional electrostatic recording materials in the dark. An electrostatic latent image can be formed by a multi-stylus electrostatic recording head, and by developing it with color toner, a recorded image similar to the conventional one can be obtained. After development, residual N (static electricity?!) remains on the dielectric layer!
The I image can be largely eliminated by directing light into the dielectric layer.

By repeating such culms, it is possible to obtain a color image without fogging.

-〇- Also, when photostatically eliminating the dielectric layer, use
By irradiating with light in which light in the near-ultraviolet to ultraviolet region of nm or less is excluded or reduced as much as possible, pre-exposure of zinc oxide can be virtually prevented to the extent that it hardly becomes a problem. Therefore, even if a latent image is formed in the dark using an electrostatic recording head immediately after photostatic discharge, a surface potential approximately the same as that for the first time can be obtained, and sufficient image density can be obtained. Repeat this process again. When the dielectric layer is irradiated with light to eliminate the electrostatic latent image that remains even after development,
A method for excluding ultraviolet light of nm or less is to transmit it through a UV filter, a yellow filter Kodak Wratten filter (NO, 2A, No. 8, No. 12), or the like. In addition, to reduce the generation of ultraviolet light of 400 nm or less from the light sludge, use a heating filament such as a tungsten lamp or halogen lamp with a lower color temperature, or use a transparent acrylic plate, glass 10-plate, etc. Irradiate light.

Static elimination using direct light from a fluorescent lamp increases fatigue of the dielectric layer,
The next latent image is less likely to be formed.

In the composition of the dielectric layer, the ratio of the insulating resin to the photoconductive zinc oxide is important and greatly influences the quality of the recorded color image. The ratio of zinc oxide is 0.5 to 1 part resin.
If it is less than 1, even if light irradiation is performed, the charge cannot be completely removed and a residual potential remains. The smaller the ratio of zinc oxide, the lower the photosensitivity during optical static elimination.

Furthermore, by increasing the ratio of zinc oxide, it becomes possible to eliminate static electricity with a small amount of light, but the following problems occur.

1) The surface charge 4<I during latent image formation decreases from the -th time. Therefore, the potential ride becomes worse throughout each process.

2) The dielectric layer becomes susceptible to fatigue, and when a latent image is formed from the second time onward, the surface potential gradually decreases over and over again.

3) The surface of the di-N layer becomes rough, resulting in poor contact with the electrostatic head and reduced resolution.

Due to the above phenomenon, the ratio of resin and zinc oxide is 1.
If it is within the range of :0.5 to 1:2.5, almost photostatic charge removal is possible.
It is also possible to form a latent image by repeating the process. In particular, a ratio in the range of 1:1 to 1:2 is advantageous in terms of static elimination sensitivity and latent image formation. In addition, by eliminating static electricity with light that excludes ultraviolet light of 400 nm or less, it becomes less susceptible to pre-exposure fatigue.
The ratio of zinc oxide can be increased, and therefore the static elimination sensitivity can be increased, and static electricity can be eliminated with a small amount of light.

These things are true when the ratio of resin and zinc oxide in general electrophotographic copying materials, so-called electrofax paper, is 1:5 to 1:5.
, 5 is completely different.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 A dielectric layer material was applied to a paste paper which had been subjected to conductive treatment on both sides of the paper support. The dielectric layer has the following composition by month:
The liquid was dissolved in a solvent and dispersed with a homomixy, the coating liquid IIJU was adjusted so that the applied film was 5 to 6 or /1, and applied with a wire bar. Make recording paper.

Insulating resin Solid content ratio LR472 Solid content 40% (Mitsubishi Rayon> 2506r l Photoconductive zinc oxide 5X-8N for electrophotography (Sho 1II1 Chemical) 150gr 1.5 Sensitizing dye Fluorene 0.5% Methanol solution 4 .4gr Rose Bengal 1% liquid 1.56r Tetrabromophenol blue 1% liquid 1.5gr A Marub stylus electrostatic recording head with double-sided control method was used on the dielectric layer of the electrostatic recording paper thus prepared, and a bottle electrode-1
100V, back electrode 13-300V, detailed II 8J! /IIR, pulse width 50
A latent image was formed in the dark under the application conditions of μsec. At this time, the surface potential of the image area was measured (SSVI-40, Kawaguchi Electric). Furthermore, after developing this with yellow toner, the surface potential was similarly measured to measure the residual potential.

Next, the entire surface of the dielectric layer was irradiated with light from a fluorescent lamp that cut off ultraviolet light of 400 nm or less, and then the surface potential was measured.

The above operation was repeated for magenta toner, cyan toner, and black toner. Similar experiments were also conducted by varying the type of irradiation light used for photostatic charge removal. The results are shown in the table.

14- (Note) Explanation of the static elimination light in the above table 1. Light m100V, 15W, colorimetric fluorescent ff1 (manufactured by Toshiba) Wratten filter No., 2A (manufactured by Kodak) transmitted light 2, light source 100V, 15W, colorimetric fluorescent ff1 (manufactured by Toshiba) direct light 3, light 81i100V, 60W1 tungsten lamp (
Color temperature 3000°K> Wratten filter N0.2A (manufactured by Kodak) transmitted light 4, light source 100V, 60W, tungsten lamp (color temperature 3000°K) direct light.

However, the amount of illumination is 3000 lux·sec in both cases.

It can be seen that when static electricity is removed using light with a wavelength of 400 nm or less cut off, the surface potential is higher in the subsequent latent image formation than when it is performed using direct light.

This indicates that it is less susceptible to pre-exposure fatigue. The difference is especially large when fluorescent light is used. This is thought to be because the light from a fluorescent lamp contains more ultraviolet light of 400 nn+ or less than the light from a tungsten lamp.

In this way, after forming latent images in different patterns,
The color images obtained by developing with yellow, magenta, cyan, and black toners were clear and fog-free for each color, and even the areas where the toners overlapped had a faithful color tone where the colors were mixed.

Note that the color of the l/ner to be developed is not limited to the three primary colors of yellow, magenta, and cyan if full color is not required, but it can be developed in any color as required, such as red, green, blue, black, etc. Needless to say, it's a good thing.

Further, for the purpose of preventing background smearing caused by repeated development, appropriate processes such as pre-wetting 1~, reverse bias development, and blotting with a plotter roller may be used.

It goes without saying that the same effect can be obtained not only by wet development but also by using dry type 17 toner.

Example 2 In the same manner as in Example 1, a material having the following formulation was applied as a dielectric layer at a ratio of 5 to 6 gr 7 m 2 to prepare electrostatic recording paper.

Insulating resin Solid content ratio LR-103 solid content 40% (Mitsubishi Rayon) 150gr i Zinc oxide 8X-8N For electrophotography (Seido Kagaku) 100gr 1 Calcium carbonate P 11 K-D D (Shiraishi calcium) 25gr Sensitizing dye Fluoreracene 0.5% methanol solution 3gr Rose Bengal 1% methanol solution 1gr 18-Tetrabromophenol blue 1% methanol solution 1gr A latent image was formed in exactly the same manner as in Example 1, and developed with a color toner q Cutting ultraviolet light of 1400 nm or less Static electricity was removed repeatedly for each color by shining the light of a fluorescent lamp on it. In addition, the surface potential at each time was measured. As a result, the value of the surface potential was 5 to 6 V higher than in Example 1, and the decrease in surface potential due to repetition was a model. The amount of light required to achieve this is 5000 lux seconds, and in the case of Example 1, the amount of light irradiated had to be large.
.

The reason for this is thought to be that the ratio of curved lead oxide in the dielectric layer is smaller than that in Example 1.

The color images thus obtained were clear and free of fog in each color.

Comparative Example In the same manner as in Example 1, electrostatic recording paper was prepared by applying the following formulation as a dielectric layer in a coating amount of 5 to 60 r/I112.

Insulating resin IR-472 solid content 40% 250 gr Calcium carbonate Pt-IK-DD 100 gr PVC powder PGR-121 (Nippon Zeon) 20 gr In the same manner as in Example 1, latent image formation, color toner development, and photostatic discharge were performed. This was repeated for each color. In addition, the surface potential of the image area at that time was measured at the same time.

The results were -108V after latent image formation and -65V after development, and there was not much difference between the colors.

Further, since photostatic charge removal cannot be performed, in an image area overlapping with an image area of the previous process, the residual potential of -125V after latent image formation and -73V after development was added and increased due to the residual potential of the previous process.

The color image obtained in this way has blackness/v for each color.
The color image quality was low. This is because the electrostatic latent image from the previous step is also developed in the next step, so it gradually darkens.

In addition, in each example, the residual potential after development depends on the development conditions,
Especially when it comes to time, J: changes a lot. That is, the closer the saturation development is, the lower the residual potential becomes, but it does not reach the potential O.

As explained above, this invention has the following advantages.

1) A latent image can be formed using a multi-stylus electrostatic recording head: When a color image is obtained from a digital signal, hard copies can be made in a manner faster than other methods.

2) Same as conventional electrostatic recording <'Kl'! This method is superior to other methods in terms of image formation, lost-one shape, simplicity, and maintenance.

3) High-quality color images that cannot be obtained with conventional electrostatic recording methods can be obtained.

4) Since the photoconductive bamboo oxide sacrificial lead of the dielectric layer is sensitized in the visible light region by a sensitizing dye, it has photosensitivity even in the image area developed with Color 21-1 toner.
Residual potential can be eliminated.

5) The pre-exposure wave force applied to zinc oxide during photostatic discharge can be made extremely small, and the surface potential decreases little when latent images are formed in the repeated process. Therefore, the surface potential of each color process can be made to be approximately the same.

6) If the voltage applied to the multi-stylus can be varied for each bin, reproducibility of tone becomes possible.

Patent applicant Rico Co., Ltd. Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi 22-

Claims (1)

[Scope of Claims] 11) A conductive layer and a dielectric layer are sequentially formed on a support to form a latent image on an electrostatic recording head in an iQ/J medium, and then a color toner is formed. Development ■ In the color electrostatic recording method in which a recatalytic image is obtained by repeating the culm process, an insulating resin and photoconductive zinc oxide are added to the dielectric layer of the electrostatic recording material.
．． A color electrostatic recording method characterized in that the weight ratio is 5 to 1:2.5. (2) The photoconductive zinc oxide is dye-sensitized in the visible light region of 400 to 700 nm (color electrostatic recording method according to claim 11). (3) When repeating the development step with color toner,
The color electrostatic recording method according to claim (1) or (21), wherein the entire surface of the dielectric layer is irradiated with light after completion of development, and then the next latent image is formed. [4] Repeating the development step with color toner, After development, the light beam that irradiates the entire surface of the dielectric layer has a wavelength of 400n.
The color electrostatic recording method according to any one of claims (1) to (3), wherein the color electrostatic recording method contains almost no ultraviolet rays having a wavelength of less than m.