JPS60149047A - Electrostatic recording medium - Google Patents

Abstract

PURPOSE:To obviate drop-out of fine lines and generation of huge dots even if a titled medium is subjected to electrostatic recording using a recording electrode having a high resolution by incorporating projections of which the distribution condition and equiv. diameter are specified in a specific range on the surface of a dielectric layer. CONSTITUTION:100-300 pieces of projections having <=2mu equiv. diameter and 30-100 pieces of projections having 3-10mu equiv. diameter for each 0.00126mm.<2> are incorporated into the surface of a dielectric layer 3 so that the slightly large projections exist partly in the very small projections. The paint for the dielectric layer is obtd. by mixing a dielectric layer resin having >=10<22>OMEGAcm volume resistivity and pigment. The dielectric layer paint is coated on a base 1 to 2-15g/m<2> dry weight and is dried. The conductive base coated thereon with the conductive layer is required to have >=100sec Bekk smoothness. If such electrostatic recording medium is subjected to recording with 1-2 recording styli, electric discharge is surely generated and the electrostatic charge is easy to be picked up thereon. Not only drop-out of fine wires arises hardly but also generation of fuge dots is decreased. Satisfactory recording is accomplished with decreased uneven density.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an electrostatic recording medium, and in particular to an electrostatic recording medium suitable for high-resolution electrostatic recording that has recently begun to be used in facsimiles and printers. Concerning electronic recording media.

(Prior Art) Electrostatic recording has excellent recording speed and record storage stability, and is widely used in the fields of facsimiles and printers. Recently, a high resolution recording of 16 dots/11j1
has been developed and has one feature superior to recording methods such as thermal recording in terms of resolution. On the other hand, with the development of computers, computers are now being used to design drawings of machinery, buildings, etc., and output the results to pen plotters.
ign) technology has been developed, however, pen plotters have problems in terms of work efficiency, as they take several minutes to ten minutes or more for complex drawings. Additionally, there was a problem with the thickness of the pen tip, making it difficult to draw thin lines around 0.1 fin.

In order to solve this problem, efforts were made to use the above-mentioned high-resolution recording for CAD drawing, but 16 do
When plotting with an ls/H recording electrode, dot reproducibility is a problem. That is, conventionally 4 to 8 dots/
When a recording paper, on which good recording was obtained by electrostatic recording using a recording electrode of 16 dots/am, is electrostatically recorded using a recording electrode of 16 dots/am, defects occur in that thin lines are missing and the lines are cut. This is compared to the diameter of the recording needle for conventional electrostatic recording, which is 60 to 100 μm or more.
In the case of the dotsβ genus, the diameter of the recording needle is as thin as about 40 μ, the contact area between one electrode and the recording paper is reduced, and the voltage application time is longer than 10 μ compared to the conventional one.
It is long at 100 p see and the applied voltage is -600 to -5
oov, whereas in the case of 16dOtS/II+, the application time was short, 5 to 10115ee, and the voltage was low, 1560cm, both of which were negative factors, and the difference between the recording needle and the recording paper surface was negative. It is thought that discharge is no longer performed reliably and thin wires are missing.

It is well known that in order to ensure the movement of charge between the recording needle and the surface of the M conductive layer, it is necessary to provide an appropriate gap (IBM Journal 192 April 19
62), [N 4011 (7) Note M Needle Tee Application '81 Pressure 560 V -, 10 p In order to reliably record with a pulse of less than Sac, 4 to 8 dots/m
It is conceivable to use a recording paper with smaller protrusions on the dielectric layer than the recording paper on which good recording quality was obtained using the recording electrodes. However, in this case, recording reliability increases and m-line omission is improved, but on the other hand, giant dots that are thought to be caused by abnormal M'ML may occur, or variations in dot density may occur, resulting in poor uniformity of solid recording. The disadvantage is that it gets worse.

(Objective of the Invention) The present invention solves the above-mentioned drawbacks and provides high resolution, 16
The object of the present invention is to provide an a-electronic recording material having excellent recording quality and suitable for electrostatic recording using dot 11 recording electrodes.

(Structure of the Invention) The present invention provides an electrostatic recording material having a conductive support and an a-conductor layer on the conductive support.
0126am", 100 to 300 protrusions with an equivalent diameter of 2μ or less and 30 to 100 protrusions with an equivalent diameter of 3 to 10p
This is an electrostatic recording material characterized by containing:

In the present invention, the equivalent diameter (d) refers to the scanning 'IJ911
d is calculated from the projection plane 82 (s) of the protrusion that appears when the S-N surface is measured with a microscope using the following formula.

(Specific explanation of the invention) When a dielectric layer is formed using various pigments and its surface condition is observed using a scanning electron microscope (hereinafter referred to as SEW) at a magnification of 1000 times, an equivalent diameter of 2p per surface area of the dielectric layer of 0.00126ja112 is observed. 100 to 300 of the following protrusions, m/T
The present invention was achieved by discovering that when MIFM 3 to 10p and protrusion B of 30 to 100m exist, fine line omissions, giant dots, and recording uniformity are improved.

If the number of protrusions with an equivalent diameter of 2 μm or less is less than 100, fine line omission will be a problem, and if it is 300 or more, fine line omission, recording density, and giant dots will be poor. Equivalent diameter 3~1
If the number of 0μ protrusions is less than 30, it will not be possible to maintain an appropriate gap between the recording needle and the surface of the dielectric layer, and the uniformity of solid recording will deteriorate.If there are more than 100, the surface condition will become irregular and fine line omissions may occur. Become.

FIG. 1 is an enlarged sectional view of a conventional electrostatic recording medium, in which 1 is a support, 2 is a low resistance layer, and 3 is an M electrolayer. The protrusions on the recording surface are irregular, and with conventional electrostatic recording materials such as protrusions, solid recording is performed by applying voltage to a large number of recording needle electrodes, and the density is high and records with good uniformity can be obtained. is 1
One recording needle or I to draw fine lines on books! When recording is performed by selecting two recording needles that are in contact with each other and applying a voltage, the protrusions are irregular, so there are fewer contact points with the recording needles.
Also! Ii! Even when touched, there are variations in the gap between the recording needle and the dielectric surface, and discharge occurs on the surface of the dielectric layer at an appropriate distance, causing static charge to build up, but in areas where the gap is long, no static charge builds up. Easy to cause thin lines to fall out.

FIG. 2 is an enlarged cross-sectional view of an electrostatic recording material in which the dielectric layer has smaller protrusions and a larger number in order to improve thin line omissions. In such an electrostatic recording material, the distance between the electrode and the surface of the vsm layer is controlled to be appropriate, and the reliability of discharge is high, and thin line omissions do not occur even when recording with one or two recording needles, but on the other hand, The electrode diameter is thought to be caused by abnormal seismic electricity.
A gigantic dot record 8 times as large was generated, and the reproducibility of fine lines was outstanding.
--- This is a problem in the case of peta recording due to the occurrence of density unevenness.

FIG. 3 is an enlarged sectional view of one embodiment of the present invention.

The number of protrusions is large, and the configuration is such that some slightly larger protrusions exist among the minute protrusions.

In such an s-electric recording material, the gap between the m-pole surface and the dielectric layer surface is controlled by some rather large protrusions,
Furthermore, since there are many minute protrusions, a suitable gap always exists between the recording electrode and the surface of the dielectric layer, and when recording with one or two recording needles, discharge occurs without fail and static charge accumulates, resulting in thin lines. Not only is it less likely to drop out, but it also produces fewer giant dots and less uneven density, making it possible to obtain good records.

Next, the materials and manufacturing method used for the electrostatic recording medium of the present invention will be explained.

The supports used in the present invention include paper-based ones such as high-quality paper, tracing paper, and resin-impregnated paper, plastic films such as polyester film, polypropylene film, polyethylene film, and synthetic paper (polyolefin synthetic paper) etc. are used.

The conductive layer is made by coating or impregnating cationic polyvinylbenzyltrimethylammonium chloride, polydimethyldiallylammonium chloride, styrene acrylic acid trimethylaminoethyl chloride anionic polystyrene sulfonate, polyacrylic acid, polyvinylphosphonate, etc. as a conductive resin. Or conductive resin and calcium carbonate, clay humiliation 1! ! It can be obtained by mixing the I material and a water-soluble or water-dispersible welding agent 9 and applying or impregnating the mixture.

The conductive agent is not limited to conductive resins, but also conductive metal oxides such as antimony-doped stannic oxide or aluminum-doped zinc oxide, and the above conductive resins and water-soluble or water-dispersible materials. It may also be a mixture of adhesives.

These conductive layer coatings are applied onto a support with a dry weight of 2.
It is coated and dried so that it becomes ~151〃.

As the coating method, commonly used bar coating method, air knife coating method, blade coating method, and gravure roll coating method can be used.

The coating amount of the conductive S layer depends on the amount of conductive agent in the conductive layer paint, but the surface electrical resistance is 1 in an atmosphere of 25@c45%RH.
It is set from 0' to 1080.

Further, the conductive layer can be applied not only to one side of the paper but also to both sides to prevent curling, fogging, etc. In this case, the same conductive layer may be provided on both sides, or separate conductive layer paints containing different types or amounts of conductive agents may be applied.

The conductive support coated with the conductive layer is smoothed using a super calender, a machine calender, a thermoplanisher, or the like.

The smoothness must be Bekk smoothness of 100 seconds or more, preferably 200 to 1000 seconds.

If smoothing is not performed, protrusions on the conductive layer or unevenness of the fibers in the case of a paper support will affect the process, resulting in bits missing, fine lines missing, etc.
The effects of the present invention cannot be exhibited due to the occurrence of giant dots or poor uniformity.

An electrostatic recording material is prepared by coating diamide on one side of the smoothed electrostatic support.

Dielectric J51 paint is obtained by mixing dielectric layer resin and pigment.

Dielectric resins include vinyl acetate resin, ethylene vinegar and copolymer resin, vinyl chloride street resin, vinyl chloride vinyl acetate copolymer resin, vinylidene chloride resin, vinyl chloride vinylidene chloride copolymer resin, acrylate ester resin, methacrylate ester resin, Resins such as butyral resin, silicone resin, polyester resin, vinylidene fluoride resin, nitrocellulose resin, styrene resin, and styrene-acrylic copolymer resin can be used.

Most resins can be used as long as they have a volume resistivity of 101Ωω or more.

As the pigment, most inorganic and organic substances with a particle size of /11 can be used. This is to create many minute protrusions on the surface of the a-electrode layer and maintain an appropriate distance between the recording paper surface and the electrodes to facilitate discharge. Inorganic pigments include calcium carbonate, clay, fired clay, talc, and titanium oxide. , lithopone, barium sulfate, calcium sulfate, silicic acid, zinc oxide, etc. Organic pigments include synthetic MIIli1 powders such as polyethylene powder, polyester powder, and polystyrene powder. The particle size distribution of the pigment varies depending on the manufacturing method, but the average particle size is 2. The following are preferable, and those with an average particle size larger than 2 μm are not preferable because the content of coarse particles becomes large. Further, in order to obtain the electrostatic recording material of the present invention, a single type of pigment is insufficient, and it is desirable to use a mixture of two or more types of pigments having different particle size distributions.

The amount of pigment added is preferably 30 to 60 mWg as a solid content of the paint. If the amount is less than 30 parts by weight, the pigment will be buried in the a-electrode layer resin, resulting in a smooth surface, and the distance between the recording paper surface and the electrodes will become too short, making it difficult to record, and the number of protrusions will also be small. It is easy for thin lines to fall out. If the amount is 60 parts by weight or more, the number of protrusions will be large, but the protrusions will be irregular and the distance between the recording paper surface and the electrodes will be uneven, resulting in areas where mJf is not covered.

The 118-color paint obtained by mixing the dielectric layer resin and preferably two or more types of pigments is coated on a smoothed conductive support so that the cloth length after drying is 3.0 to 10.0 p7z. It is applied like this.

As the coating method, the commonly used bar coating method and gravure roll coating method can be used.

Hereinafter, the electrostatic recording material of the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example! 20 of vinyl chloride, vinyl acetate (55:45) copolymer
% solution (solvent toluene: acetic acid ethini 8 (120) 300!
Part f contains 30 parts by weight of calcium carbonate (trade name N5600 manufactured by Nitto Funka Co., Ltd.) with average particle size i and slI as a pigment, and silica gel (trade name Thyroid 74) with a primary particle diameter of 0.01 u.
．． 10 parts by weight (manufactured by Fuji Davison Chemical) were added and dispersed for 1° with a paint conditioner to create a 1 fsta layer paint. Commercially available synthetic paper film (product name Yubo TPG90)
After drying, the amount of conductive eyebrow fat applied to Oji Yuka Synthetic Paper is 3.
．． A conductive support was prepared by coating the solution in an amount of O11. The Beck smoothness of the conductive layer was 900 seconds. The weight of the dielectric layer paint after drying on the conductive layer of the conductive support is 6.0 gAr? An electrostatic recording medium was prepared by applying the following. To remove thin lines, use a commercially available multi-stylus electrode with a line density of 16 dots/+u that has been adjusted so that thin lines can be recorded with a single recording stylus, and the voltage is -250 V for the bottle electrode.
Recording was performed with a voltage control electrode of +250 V and an application time of 5 μsec, and development was performed with positively charged liquid toner. Thin line omissions are calculated by adding the length of the omission in a thin line of length 3000111, dividing the result by the length of the original thin line, and displaying the value as a percentage. 5% or less is O (good), 5 to 10% is Δ ( 10% or more was judged as × (poor).

In the case of this example, 2% was good.

Examples 2 and 3 and Comparative Example 1.2 An electrostatic recording medium was prepared in the same manner as in Example 1 (!) except that the addition ratio of pigment N5600 and Thyroid 75 was changed. The results are shown in Table 1. Shown below.

Comparative Example 1 has fewer protrusions and has a large number of protrusions with an equivalent diameter of 211 or less, and has good thin line omission, but has a large number of giant dots and a small number of protrusions with an equivalent diameter of 3 to 10 μm, resulting in density unevenness during solid recording. . In Comparative Example 2, there were almost no protrusions with an equivalent diameter of 2Il or less, and the number of protrusions with an equivalent diameter of 3 to 10μ was small, causing thin wire omissions.

In the range of Examples 1 to 3, fine line omission, large dots, and uniformity were also good, and the number of protrusions with an equivalent diameter of 2II or less was 100 to 100.
300 pieces and 30 to 100 protrusions with an equivalent diameter of 3 to 10 u
Good within the range of

Example 4 300 parts by weight of a 20% solution of polyester M resin (solvent: toluene:ethyl acetate 80:20) was added as a pigment with an average particle size of 1.
9μ calcium carbonate (product name: N5200 manufactured by Nichishu Powder)
20 parts by weight and 20 mffi parts of titanium oxide with a primary particle diameter of 0.03 μm (product 6 1 tanlu+++ Oxide P25 manufactured by Nippon Aerosil Co., Ltd.) were added and dispersed for 10 minutes with a paint conditioner to prepare a layered paint. A conductive support was prepared by coating commercially available high-quality paper with a basis weight of 501 Arf with a coating material after drying a conductive resin to a thickness of 5.0 μm to give a smoothness of 500 seconds after supercalender treatment. The above dielectric layer is placed on the conductive layer of the conductive support.
The weight after drying the N paint is 6.019. An electrostatic recording material was prepared by coating the material in a uniform manner. The recording results are shown in Table 2.

Comparative Example 3 A dielectric layer consisting of 20 parts by weight of calcium carbonate (product name: 5sso manufactured by Nitto Funka Co., Ltd.) with an average particle size of 2.6 μ as a pigment in the resin composition of Example 4 and 20 parts by weight of the same titanium oxide as in Example 4. The results of the electrostatic recording medium are shown in the second volume.

Comparative Example 4.5 One type of pigment was added to the resin composition of Examples 1 and 4, that is, Comparative Example 4 was Example 4 with an average particle size of 1.91I.
Same calcium carbonate as Comparative Example 51, average particle size 0003
An electrostatic recording material made of a TSM layer containing 40 parts by weight of titanium oxide as in Example 4 of μ was produced. The results are shown in Table 2.

Example 4 uses titanium oxide in place of the thyroid 74 of Comparative Example 2, and even with the same addition amount as the thyroid 74, the number of protrusions with an equivalent Ia diameter of 2μ or less is 100 to 300, and the number of protrusions with an equivalent diameter of 3 to 10p is 30. The number of dots is in the range of 100 to 100, and both fine line omission, giant dots, and uniformity are good.

In Comparative Example 3, the average particle size of calcium carbonate is 2.6μ larger than that in Example 4, and protrusions with an equivalent diameter of 11μ or more appear, making it difficult to pull out fine lines.

In Comparative Example 4, only one type of calcium carbonate with an average particle size of 1.9 μm was used, but only protrusions with an equivalent diameter of 3 to 10 μm appeared, and the number of protrusions was small, making it difficult to pull out fine particles.

Comparative Example 5 has only small titanium oxide particles with an average particle size of 0.03μ, and has a large number of protrusions with an equivalent diameter of 21I or less, and although thin wire removal is somewhat good, there are few protrusions with an equivalent diameter of 3 to 10μ, so it is large. Dots occur and uniformity deteriorates.

The present invention has been explained above along with Examples and Comparative Examples, but
The pigment of the present invention has 100 to 300 protrusions with an equivalent diameter of 2p or less on the surface of the recording paper, and 30 protrusions with an equivalent diameter of 3 to 10u.
The types and amounts of pigments to be added are not limited to those in the examples as long as they can be coated in a range of 100 to 100 pigments.

(Effects of the Invention) As is clear from the above description, according to the present invention, even when electrostatic recording is performed using a high-resolution recording electrode, there is no occurrence of thin line omissions or giant dots, solid recording, and thin line recording. This makes it possible to obtain an electrostatic recording medium with excellent recording quality without any variation in density.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a conventional electrostatic recording medium, FIG. 2 is an enlarged sectional view of a comparative example of the present invention, and FIG. 3 is an enlarged sectional view of an embodiment of the present invention. 1. Support 2, (ffi resistance layer 3, dielectric layer Applicant Oji Paper Co., Ltd. Agent Masaaki Ogawa 1st 2nd 3rd i=-1 and 2

Claims (1)

[Claims] In an electrostatic recording material having a conductive support and a dielectric layer on the conductive support, the surface of the dielectric layer is coated with 0.001261
100 to 30 protrusions with an equivalent diameter of 211 or less per 11-
An electrostatic recording material characterized in that it contains 0 protrusions and 30 to 100 protrusions with an equivalent diameter of 3 to 10 u.