JPH0425540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing plate for two-color electrostatic printing and a printing method thereof, and more specifically, a conductive ink layer and an insulating ink layer are formed on a zinc oxide photoreceptor by a thermal transfer recording method or the like. The present invention relates to a two-color electrostatic printing printing plate characterized by forming a two-color electrostatic printing plate, and a two-color electrostatic printing method using the plate.

Conventionally, letterpress printing, gravure printing, offset printing, etc. have been used to obtain a large number of printed materials, but simple offset printing is widely used for office printing. In this manufacturing method, a simple offset master plate is created by an electrophotographic method, but the offset printing method using the master plate lacks simplicity because it uses water and ink.

The purpose of the present invention is to have the simplicity like a copying machine,
An object of the present invention is to provide a two-color electrostatic printing printing plate and a printing method thereof, which can easily print about 100 to 1000 copies and also achieve a two-color image.

Currently, in general offices, most black-and-white originals are used, and even if there are color originals, it is thought that there is little need for full-color originals. However, it is believed that there is a potential need for black and white plus one color. Although several two-color copying systems have been proposed, there are currently no copying machines on the market.

The present invention provides a printing plate for two-color electrostatic printing that achieves a two-color image, and a printing method thereof, which consists of a conductive ink layer and an insulating ink layer arranged in a pattern on a zinc oxide photoreceptor. The present invention relates to a two-color electrostatic printing printing plate and a two-color electrostatic printing method using the plate. That is, a printing plate for two-color electrostatic printing is charged, reversely developed with A color toner having the same polarity as the charged charge, exposed to light over the entire surface, and then positively developed with B color toner having a polarity different from the charged charge. Then, the polarities of the A and B color toners are made the same by recharging, and the A and B color toners are transferred to the transfer object and fixed, or the printing plate is charged and the polarity of the A and B color toners is the same. Reversal development is carried out with A color toner having the same polarity as the charged charge, and the image is transferred onto the transfer target.Then, the printing plate is recharged, and normal development is carried out with B color toner having the opposite polarity to the charged charge. This is a two-color electrostatic printing method that is characterized by transferring and fixing onto a transfer body.

To explain the present invention in more detail with reference to the drawings, taking a thermal recording method as an example, as shown in FIG. A zinc oxide photoreceptor 6 having a zinc oxide fine powder-resin photoreceptor layer 5 provided on the body 4 is arranged so that the ink layer 2 and the photoreceptor layer 5 face each other, and as shown in FIG. Then, thermal transfer is performed to form the photosensitive layer 5 of the zinc oxide photoreceptor 6.
The conductive heat-sensitive transfer ink layer 2 of the conductive heat-sensitive transfer material 3 is transferred thereon. Here, the photosensitive layer portion of the zinc oxide photoreceptor 6 to which the conductive heat-sensitive transfer ink layer 2 has been transferred becomes an electrostatically conductive portion and releases corona charges.

Next, as shown in FIG. 3, an insulating heat-sensitive transfer material 9 having an insulating heat-sensitive ink layer 8 provided on a support 7 and a zinc oxide photoreceptor 6 to which the conductive heat-sensitive transfer ink layer 2 has been transferred are combined with the ink layer 8. The insulating heat-sensitive transfer ink layer 8 of the insulating heat-sensitive transfer material 9 is placed on the photosensitive layer 5 of the zinc oxide photoreceptor 6 by the thermal element TPE, as shown in FIG. Heat transfer. Here, the portion of the photosensitive layer of the zinc oxide photoreceptor 6 to which the insulating heat-sensitive transfer ink layer 8 has been transferred becomes an electrically insulating portion and does not allow corona charges to escape.

As described above, as shown in FIG. 5, a conductive portion (conductive thermal transfer ink layer portion) 10 and an insulating portion (insulating thermal transfer ink layer portion) 11 are formed on the photosensitive layer 5 of the zinc oxide photoreceptor 6. A printing plate 12 for two-color electrostatic printing is produced.

In the above, a thermal transfer recording method using a thermal head using a thermal element TPE has been described, but it goes without saying that thermal transfer recording using a laser is also effective as a method for obtaining high-resolution images. Further, in FIGS. 2 and 4, the members 3 and 6 and 9 and 6 are shown separated from each other to facilitate understanding, but in reality, they are usually placed in contact with each other.

Here, the thermal transfer material used in the thermal transfer recording method is one in which a heat-melting ink layer is formed on a base film, and in the present invention, a conductive thermal transfer material 3 having a conductive thermal transfer ink layer 2 and a conductive thermal transfer material 3 provided with a conductive thermal transfer ink layer 2 are used. An insulating heat-sensitive transfer material 9 provided with an insulating heat-sensitive transfer ink layer 8 is used. As the base film, conventionally known base films can be used as they are, and there are no particular restrictions, such as polyester film, polycarbonate film, triacetyl cellulose film, nylon film, high quality paper, capacitor paper, glassine paper, tracing paper, etc. , 3.5μ to 25μ thick films such as cellophane. The conductive thermal transfer ink layer 2 is composed of a conductive agent and a binder. The conductive agent is copper,
Iron, aluminum, silver, zinc, black iron oxide, copper oxide, copper iodide, copper chloride, silver oxide, cobalt oxide,
Conductive powders such as indium oxide and carbon black, polymeric quaternary ammonium salts, and polymeric electrolytes such as sodium polystyrene sulfonate can be used. As the binder, substances that can be easily melted by heat are used, such as waxes such as carnauba wax, wood wax, beeswax, and microcrystalline wax, or resins such as low molecular weight polyethylene and polyvinyl stearate. In addition, easily heat-meltable substances such as polystyrene, styrene-butadiene copolymers, polyvinyl acetate, cellulose esters, cellulose ethers, acrylic resins, or lubricating oils are used as softeners.

The insulating thermal transfer ink layer 8 is composed of an insulating agent and a binder. As the insulating agent, dielectric (insulating) resin powder such as epoxy resin, melamine resin, phenolic resin, fluorine resin, polyimide resin, etc. can be used. The binder and softener used are the same as those for the conductive transfer ink layer 2 described above. however,
When the binder has sufficiently high insulating properties, it is not necessarily necessary to contain an insulating agent.

In addition, a conductive ink layer and an insulating ink layer can also be formed on a zinc chloride photoreceptor by a pressure-sensitive recording method. A method for forming a conductive ink layer is writing with a writing instrument containing a conductive substance (mainly carbon black) such as a black pencil, black crayon, charcoal, conte, black felt pen, or black ballpoint pen. Alternatively, you can write on black carbon paper or type on a typewriter. In addition, as a method for forming the insulating ink layer, a method of pressure-sensitive transfer of a pressure-sensitive recording medium having an insulating ink layer can be used, and the insulating ink layer is made of a high-resistance material such as inorganic or organic pigment or resin powder. This is heated and mixed with waxes and oils such as carnauba wax, paraffin wax, mineral oil, vegetable oil, dispersants, surfactants, metal soap, etc. in an ink mill or ball mill, and this is used to make thin paper or plastic film. It is applied to the surface of the surface and allowed to harden and set at room temperature.

Hereinafter, an example of a process of performing two-color electrostatic printing using this printing plate 12 for two-color electrostatic printing will be explained. Other examples will be explained in Examples.

This printing plate 12 for two-color electrostatic printing is uniformly negatively charged by a charging device 13, as shown in FIG. Then, the surface of the photosensitive layer of the zinc oxide photoreceptor has countless micropores, and when a conductive part is formed with conductive ink on the surface of the photosensitive layer, the conductive ink penetrates into the micropores of the photosensitive layer. As a result, the conductive portion and the conductive support are electrostatically short-circuited, and the charge escapes only from the conductive portion 10, forming an electrostatic latent image. Next, as shown in FIG. 7, reversal development is performed using a negative A color toner 14 having the same polarity as the charged charge by a magnetic brush method, a cascade method, etc., and the A color toner 14 is applied to the conductive portion 10. Attach to. Next, as shown in FIG. 8, when the printing plate 12 for two-color electrostatic printing is exposed entirely to white light, a negative charge remains in the insulating portion 11, so that a positive B color is applied as shown in FIG. When toner 15 is similarly developed using the magnetic brush method, cascade method, etc., the B color toner 1
5 is attached to the insulating portion 11. Next, as shown in FIG. 10, the A color toner 14 and the B color toner 15 are negatively (or positively) charged by the charging device 13 in order to match their polarities, and then the transfer target 16 is charged as shown in FIG. A charging device is placed on the printing plate 12 for two-color electrostatic printing that has been developed with the toners 14 and 15, and a charging device generates a positive (or negative) corona discharge of a polarity different from that of the toners 14 and 15 from the back side of the transfer target 16. 13, the toners 14 and 15 are applied to the transfer material 1 on the two-color electrostatic printing plate 12.
6 is electrostatically transferred. Next, as shown in FIG. 12, the transfer target 16 is separated from the printing plate 12 for two-color electrostatic printing, and heated, so that the A color toner 14
The B color toner 15 is fixed onto the transfer object 16.

Next, examples of the present invention will be described below.

[Example 1] Carbon black 28 parts by weight Parafine wax (microcrystalline wax melting point 80°C) 14 Trichloroethane 57 Dehydrated castor oil 1 Heat and mix well in the above ratio to form a slurry-like conductive substance coating liquid shall be. This is uniformly applied to a thickness of 5μ on a 15μ thick capacitor paper and dried to obtain a conductive heat-sensitive transfer material.

Polyethylene powder 7 parts by weight Microcrystalline wax 11 〃 Polyvinyl butyral 2 〃 Methyl alcohol 80 〃 Mix well in the above proportions and apply it uniformly to a thickness of 7μ on 15μ capacitor paper using a coating machine equipped with a drying device. It is dried to form an insulating heat-sensitive transfer material.

Using the conductive heat-sensitive transfer material and the insulating heat-sensitive transfer material produced as described above, a conductive heat-sensitive transfer ink image and an insulating heat-sensitive transfer ink image were printed on zinc oxide photosensitive paper TO40 manufactured by Tomegawa Paper Manufacturing Co., Ltd. using a heat-sensitive transfer printer. An image is formed to form a printing plate for two-color electrostatic printing.

This printing plate for two-color electrostatic printing was uniformly subjected to negative corona discharge (-6.5KV) in a dark place, and black negative type toner LiofaxN- manufactured by Toyo Ink Mfg. Co., Ltd.
1 and a developer consisting of Carrier EFV150/250 manufactured by Nippon Tetsuko Co., Ltd., using a magnetic brush method.
A black toner image is formed on the conductive area, and then positive development is performed in a bright place using a positive type red developer (manufactured by Toyo Ink Mfg. Co., Ltd.) using a magnetic brush method, and the red toner image is applied to the insulating area. After forming the image and then applying a uniform positive corona discharge (+6.5KV), the paper is placed and a negative corona discharge (-
6.5 KV), black and red toners were electrostatically transferred onto the paper, and fixed by heating to obtain a red and black two-color printed matter. By repeating this operation, a large number of color printed matter could be obtained.

[Example 2] Carbon black 24 parts by weight Beeswax 12 Trichloroethane 61 Dehydrated castor oil 3 The above ratios are thoroughly heated and mixed to form a slurry-like conductive substance coating liquid. This is applied uniformly to a thickness of 10μ on a 15μ thick capacitor paper and dried to obtain a conductive heat-sensitive transfer material.

Vinyl chloride/vinyl acetate copolymer 10 parts by weight Carnauba wax 7 〃 Castor wax 11 〃 Ethyl acetate 50 〃 Toluene 22 〃 Heat and mix well in the above proportions, and make a 15μ thick layer.
It is coated on capacitor paper to a thickness of 10μ and dried to form an insulating heat-sensitive transfer material.

Using the conductive heat-sensitive transfer material and the insulating heat-sensitive transfer material produced as described above, a conductive heat-sensitive transfer ink image and an insulating heat-sensitive transfer ink image were printed on zinc oxide photosensitive paper TO55 manufactured by Tomegawa Paper Manufacturing Co., Ltd. using a heat-sensitive transfer printer. An image is formed to form a printing plate for two-color electrostatic printing.

This two-color electrostatic printing plate was fixed to a pin bar attached to a grounded metal plate, and a negative corona discharge (-6.5 KV) was uniformly applied in a dark place. negative type toner
Liofax N-1 and carrier made by Nippon Tetsuko Co., Ltd.
Reversal development is performed using a magnetic brush method using a developer consisting of EFV150/250 to form a black toner image on the conductive area, and the paper with pin holes is inserted into the pin bar and placed on the paper. Positive corona discharge (+6KV)
The black toner is electrostatically transferred to the paper and fixed by solvent vapor. Next, in a bright place, the printing plate for two-color electrostatic printing was uniformly subjected to negative corona discharge in the same way, and then it was developed using a positive type blue developer (C manufactured by Toyo Ink Mfg. Co., Ltd.) using the magnetic brush method. Positive development is performed to form a blue toner image on the insulating part, and the paper on which the previous black toner image was formed is inserted and placed on the pin bar again to align the register, and a negative toner image is applied to the paper. A blue toner was electrostatically transferred by applying corona discharge (-6.5 KV) and fixed by solvent vapor to obtain a two-color print of blue and black. By repeating this operation, a large number of color printed matter could be obtained.

[Example 3] Carbon black 17 parts by weight Paraffin wax (n-paraffin melting point 80
~85°C) 17 Trichloroethane 65 Dehydrated castor oil 1 Heat and mix thoroughly at the above ratio to form a slurry-like conductive substance coating liquid. This is uniformly applied to a thickness of 5μ on a 12μ thick polyethylene terephthalate and dried to form a conductive heat-sensitive transfer material.

Fluorine resin powder 5 parts by weight Parafine wax 15 〃 Trichloroethane 80 〃 Heat and mix well in the above ratio, apply this evenly to a thickness of 7μ on a 12μ thick polyethylene terephthalate, dry and insulate. It is used as a thermosensitive transfer material.

Using the conductive heat-sensitive transfer material and the insulating heat-sensitive transfer material produced as described above, a conductive heat-sensitive transfer ink image and an insulating heat-sensitive transfer ink image were printed on zinc oxide photosensitive paper TO57 manufactured by Tomegawa Paper Manufacturing Co., Ltd. using a heat-sensitive transfer printer. An image is formed to form a printing plate for two-color electrostatic printing.

Using this printing plate for two-color electrostatic printing, Example 1
By using the black negative type developer and the red positive type developer, a red and black two-color printed matter could be obtained by the method of Example 2.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing a state in which a conductive heat-sensitive transfer material and a zinc oxide photoreceptor are opposed to each other, and FIG. An explanatory diagram showing thermal transfer. Figure 3 is an explanatory diagram showing a state in which an insulating thermal transfer material and a zinc oxide photoreceptor to which a conductive thermal transfer ink layer has been transferred are facing each other. Figure 4 is an explanatory diagram showing an insulating thermal transfer using a thermal element TPE. FIG. 5 is an explanatory diagram showing thermal transfer of an ink layer, and FIG. 5 is an explanatory diagram showing a two-color electrostatic printing plate having a conductive part and an insulating part.
Figure 2 explains how to use the printing plate for two-color electrostatic printing, Figure 6 is an explanatory diagram showing the printing plate for two-color electrostatic printing in a uniformly charged state, and Figure 7 shows the state in which the printing plate for two-color electrostatic printing is uniformly charged. Figure 8 is an explanatory diagram showing a state where the entire surface is exposed to light, and Figure 9 is an explanatory diagram showing a printing plate which has been normally developed with B color toner. Figure 10 is an explanatory diagram showing the operation for making the polarity of A color toner and B color toner the same, and Figure 11 is an explanatory diagram showing the process of electrostatically transferring A color toner and B color toner to a transfer target at the same time. Explanatory diagram showing, 1st
FIGS. 2A and 2B each show an explanatory diagram showing a fixed transfer target. DESCRIPTION OF SYMBOLS 1...Support, 2...Electroconductive heat-sensitive transfer ink layer, 3...Electroconductive heat-sensitive transfer material, 4...Electroconductive support, 5...Photosensitive layer, 6...Zinc oxide photoreceptor, 7...
...Support, 8...Insulating heat-sensitive transfer ink layer, 9...
... Insulating thermal transfer material, 10 ... Conductive portion, 11
...Insulating portion, 12...Printing plate for two-color electrostatic printing, 13...Charging device, 14...A color toner, 1
5... B color toner, 16... Transferred object.

Claims (1)

[Claims] 1. A printing plate for two-color electrostatic printing, characterized in that a conductive ink layer and an insulating ink layer are respectively formed in a pattern on a zinc oxide photoreceptor. 2. The printing plate for two-color electrostatic printing according to claim 1, wherein a conductive heat-sensitive transfer ink layer and an insulating heat-sensitive transfer ink layer are formed in a pattern by a heat-sensitive transfer recording method. 3. A printing plate for two-color electrostatic printing in which a conductive ink layer and an insulating ink layer are formed in a pattern on a zinc oxide photoreceptor is charged, and the charged charge is reversed with A color toner having the same polarity as the charged charge. After developing and exposing the entire surface to light, positive development is performed using a B color toner having a polarity different from the charged charge, and then recharging is performed to make the polarity of the A and B color toners the same. A two-color electrostatic printing method characterized by transferring toner to a transfer target and fixing it. 4 A printing plate for two-color electrostatic printing in which a conductive ink layer and an insulating ink layer are formed in a pattern on a zinc oxide photoreceptor is charged, and the charged charge is reversed with A color toner having the same polarity as the charged charge. It is characterized in that it is developed and transferred to the transfer object, then the printing plate is recharged, normal development is performed with a B color toner having a polarity different from the charged charge, and the printing plate is transferred to the transfer object and fixed. A two-color electrostatic printing method.