JPS59223461A - Formation of electrostatic printing master - Google Patents

Abstract

PURPOSE:To obtain high electrostatic charging potential by subjecting a photoconductive plate to uniform electrostatic charging and image exposing to form an electrostatic latent image thereon and developing and fixing the image by using a powder toner having a dielectric constant in a specific range. CONSTITUTION:A powder toner having <=2.6 dielectric constant is used for the powder toner for developing an electrostatic latent image to a sensible image. Materials such as styrene, styrene/acryl alone or their copolymer, a polyester resin, epoxy resin, olefin resin, etc. are used as the binder resin of the toner and pigments such as carbon black, iron oxide powder etc. and dyes such as nigrosine, triphenyl amine, etc. are used as the coloring material thereof. The powder toner is so ground as to have 5-30 micron grain size after compounding and kneading. The materials, compounding ratio, production process, etc. are so selected as to provide <=2.6 dielectric constant. Flash fixing or pressure fixing with which thermal or mechanical denaturation arises hardly is executed as a method for fixing the toner image on ZnO photosensitive paper. A copied print having always satisfactory density of a practicable image is easily formed from the electronic printing master formed by the above-mentioned forming method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for forming an electronic printing master, and particularly to a method for forming an electronic printing master used in a printing method using an electrophotographic method.

BACKGROUND OF THE INVENTION Electrophotographic printing has been known for a long time. For example, in U.S. Pat.
34' electronic printing device, etc. This is done by forming a powder image on the original electrical plate and fusing or fixing it using an electrostatic photographic method, and then forming a non-photosensitive insulating image figure, a stamp AC remaster, on the original electrical plate. Then, this printing master is uniformly charged with gold and then uniformly irradiated with the original. Because the charge is retained only on the non-photosensitive image area and discharged on the photosensitive area, the charged powder is deposited on the partially charged plate to form the entire powder image, and the powder image is completely formed. The process involves repeating the above steps in order to transfer the image onto a suitable image support.

This type of printing master formed by such a conventional method is, for example, a method in which a toner image is fixed on a photosensitive sheet such as a ZnO-based photosensitive sheet in which photosensitive particles are dispersed in a binder resin. However, with a print master using such a conventional forming method, it is not possible to obtain a sufficient charging potential f of the image area on the print master during printing, making it difficult to obtain good copies. Met.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method f for forming an electronic printing master that can solve the problems of the conventional printing master forming method as described above and can obtain a high charge iu level.

The method for forming an electronic printing master according to the present invention is 9°0♂
: A electrostatic latent image is formed by electrifying a electrostatic plate at an image exposure source, and the electrostatic latent image is developed using a powder toner with an induction rate of 6 or less to form a toner image. and fixing the toner image on the covering plate 4i.

Embodiments Next, the present invention will be described in detail with reference to embodiments of the present invention based on the accompanying drawings.

FIG. 7 schematically shows an electronic printing device -fll implementing the method of forming an electronic printing master of the present invention.

In FIG. 1, reference numeral 1 indicates a rotating drum, and the rotating drum 1 has retaining claws on its circumferential surface and supports a photosensitive paper 10. As shown in FIG.

A cleaning device 8 is installed around the entire rotating drum 1.
Equipment such as a charger 4, a uniform exposure yt, a lamp 13, a developing device 5, a transfer coroton 6, and a fixing device 11 for fixing the powder toner image on the photosensitive paper 10 are arranged.

To create a print master, a photosensitive paper 10, originally a conductive plate, is wrapped around a rotating drum 1 and supported, then charged with a charger 4, and further illuminated with an original illumination lens 14 on a document table 3. The image is projected onto photosensitive paper 10 through a projection lens 2 to form a still image. Next, the latent image is visualized by a developing device 5, and the powder toner image is fused and fixed onto the photosensitive paper 10 by a developing device T to form a printing master.

In addition to creating this print master, the powder toner used to visualize the electrostatic latent image is one having a dielectric constant of 6 or less, according to the present invention.

The dielectric constant of the powder toner in this case is measured as follows. That is, a H' of the powder toner
c 'e Easy 2Jc with a pressure of about 300 kg/cdl
m-thickness approximately, formed into a bipharyngeal disc, /KH2, /θ
Apply the pressure (2) and find the dielectric constant.

As described above, the powder toner having a dielectric constant of 6 or less used in the present invention can be prepared by combining known materials.
r4 'iNsanruRen:'.

That is, as the binder resin for the toner, any known materials such as styrene, styrene, acrylic, etc. alone or copolymers, polyester resins, epoxy resins, olefin resins, etc. can be used. Pigments such as carbon black and iron oxide powder, dyes such as nigrosine and triphenylamine may be used as colorants depending on the coloring material. Furthermore, it is also possible to stabilize the charge by using known chromium-containing azo dye complexes, nigrosine dyes, 6 types of 9th class anthonium salts, pyridinium salts, etc. as charge opening agents. However, this charge control agent must be selected according to the charge code of the photoreceptor to be used.

Powder toner can be manufactured by combining all of these materials, blending and kneading, and then pulverizing to a particle size of 5 to 30 microns, but of course, other known methods such as spray drying can be used. It may also be manufactured by a suspension polymerization granulation method or the like. What is important here is that the powder toner used in the method of forming an electronic printing master of the present invention should have a dielectric constant of 6 or less.
It is necessary to select 1.2 and their blending ratio, manufacturing method, etc.

In addition, in the present invention, it is advantageous to use the above-mentioned ZnO photosensitive paper as the original Sakai conductive plate of the printing master, and as a method of fixing the photosensitive toner image on this ZnCJ paper, it is preferable to use the photosensitive paper. Flash constant or pressure fixing is desirable because thermal or mechanical denaturation is less likely to occur.

Static printing of a large number of sheets using the electronic printing master thus formed by the forming method of the present invention is carried out as follows. The print master with toner image on photosensitive paper is band v1. It is charged by the vessel 4, and then uniformly charged by the Fukimoto lamp 13.

-i, the charge on the photosensitive paper 10 that has been completely charged is uniformly discharged by A'i leaving only the insensitive and non-isoelectric toner image area. Only the image part is formed by the F old trimmer using IEb 4r+J and visualized by the n1 developing machine 5. Next, f□'41
The toner image 11 is sent to the transfer section in synchronization with the rotation of the rotary drum 1, and the toner image on the print master is transferred to the transfer paper by the transfer corotron 6K, and then fixed by the fixing device 9.
Obtain medium-sized photographs exclusively on the 1st image and 4th paper tray.

On the other hand, the residual toner on the printing master after transfer is cleaned by the cleaning device 8, and - printing cycles are completed. Thereafter, the printing cycle is repeated for the number of copies required.

In the embodiment described above with reference to FIG.
．． ! )'' Various variations are available, for example, mark A11l.
J master type When printing a large number of sheets, use a powder toner with a low dielectric constant of less than 1 and 2 when forming a printing master, and when printing a large number of sheets. Alternatively, a powder toner having a higher dielectric constant may be used.

Next, in order to confirm the effectiveness of the method for forming an electronic printing master according to the present invention, we prepared powder toners with various impoverishment rates and conducted specific experiments. , Comparative Example (K), Example (C), Example 2 and Example 3
I will explain about it.

In each of these experiments, a ZnO-sensitive element was used as the original conductive plate of the printing master, and the developing device for forming the printing master and the developing device for printing were separated, and the developing device for printing was provided with one on each side. I put the same developer in it.

[Comparative example/]

As a powder toner, one with an electric sensitivity of S and O is used, and the particle size is 1.
Print master in combination with 00 micron iron oxide powder (January 40 Iron Powder Co., Ltd.)! This was used as a developer for forming L11 images. This developer is used to flash-fix the U'f, I-shaped toner image (foot layer energy 3-OJ/ct
A printing master was formed as /l). When printing was carried out using this printing mask, only copies with extremely low image quality were obtained. In this case, the charging potential of the image area of the printing master after banding 1EL11 was -/:1OV.

The composition of the toner used here is as follows.

Tetraheptylammonium chloride...
'AM91 [Comparative Example 12] Printing 1 was carried out in exactly the same manner as in Comparative Example, except that a toner with an electric sensitivity of 3°/ was used as the powder toner. The image density was high, and the image intensity was enough to make it look like a samurai nakatsu trap.

Emperor L of the seventh platform: j, Jhe Gengo printing master's image department 'it2 '1j1: 'Il 1st place is -2b
OV te;joofc.

In addition, the combination of /hitoner used here is as follows.

〔Example/〕

When printing was carried out in exactly the same manner as in Comparative Example except that a toner having a dielectric constant was used as the powder toner, a copy with high image density was obtained. In that case, the charging potential of the l1ill image area of the print master after charging and exposure is -3kOV
Met.

Incidentally, the toner used here was m or the following.

Carbon black (yaya, tsu, ka 1.6.-7 to 330) ``'Yariba [implementation f! 1.2'] Except for using a toner with a dielectric constant of 2.5 as the powder toner,
When printed in exactly the same manner as in Comparative Example, a copy with high image density was obtained as in Example. In this case, after charging and exposure, the charging tα position of the image 815 of one print master was −+/θV.

The composition of the toner used here is as follows.

Styrene/n-butyl methacrylate copolymer...
9 part carbon black, Yaya, 2) engineering, 1EiJ, 4Bp7, 7oo)
“°° 5-part nigrosine dye
... ab [Example 3] A pressure fixing (linear pressure Okg/cm ) was performed using a pressure gradient toner with a trace electric current of 3 as a powder toner.
When I printed with this print master, there was enough [1itl]
Obscure objects with image inclinations are obtained.
(1) Mark Aji! l ”f sl'-17) Ilj
ll Curved part (7) 'The potential was -5oov.

The composition of the toner used here is as follows.

Carbon black, @··
Part 5 (manufactured by Cabot Corporation, trade name Regal 330) The graph in Figure 2 shows the dielectric constant of the powder toner and the results after charging and exposure based on the experimental results of Comparative Example/C and Example/C. It shows the relationship with the charging potential of the image area of the print master. In the graph in Figure 4.2, the shaded area indicates the practical range of the 'r1f electric potential of the print master image area, and
If the tunki position is not in this range, it will be difficult to obtain a practical image quality when copying.

As is clear from Durham in Figure 1, the practical 11a image
A charging potential tIIflll sufficient to obtain a copy with a density of
To make an electronic printing master that can be obtained in the image section,
It is best to use a powdered toner with an electric rating of 6 or less.

Effects of the Invention As described above, according to the method for forming an electronic printing master of the present invention, a magnetic printing master is created which can provide a sufficient charging potential total IQ to the ll7ii image area during printing, so that From the master, it is always possible to easily produce good quality printed copies of practical images.

[Brief explanation of the drawing]

FIG. 7 is a schematic cross-sectional view showing an example of an electronic printing device that implements the method for forming an electronic printing master of the present invention, and FIG. 2 shows the toner @electrification rate and the charging potential of the printing master image after being charged and exposed. FIG. 1... Rotating drum 2... Projection lens 3
...Manuscript table 4...Tei'giki 5...
Developed Buddha 6...Transfer Corotron...)
2.Touch fixing device 8...Cleaning device 9...
Sadanuma sowing, 10...V, conductive sheet 11.
...Transfer paper 12...Output tray 13...
Uniform exposure lamp 14...Original illumination lamp 15...Cleaner lamp

Claims (1)

[Claims] (1) A conductive plate is uniformly charged and image exposed to form an electrostatic latent image, and the electrostatic latent image is developed using a powder toner with a contact ratio of 2.6 or less to form a toner. A method of forming an electronic printing master comprising forming an image and fixing the toner image on the photosensitive plate. (, 21) The method for forming an electronic printing master according to item (1), in which the fixing is performed by constant fludge fixing. (a method for forming an electronic printing master according to item 4);