JPS63151456A - Offset press - Google Patents

Abstract

PURPOSE:To dispense with lithographic plate making and mounting works, by a method Wherein the outer surface corresponding to an image line part of a magnetic drum is magnetized to form a magnetic latent image and a magnetic fine powder with a surface subjected to ink compatibility treatment is transferred to a plate cylinder to which ink repelling treatment is applied and ink is supplied to the magnetic fine powder part of the plate cylinder to perform printing. CONSTITUTION:After image data is converted to the data of an image line part to be magnetized, the data corresponding to the image line part is sent to a magnetic head 1 and the part corresponding to the image line part of a magnetic drum 1 is magnetized. When the outer surface magnetized of the magnetic drum 1 passes a magnetic fine powder supply part 4, a magnetic powder containing a fixing agent and having a surface receiving ink compatibility treatment is supplied to the magnetic drum 1 to be adhered and held only to the magnetic latent image part and subsequently brought into contact with a plate cylinder 7. After the magnetic powder supply and fixing processes are finished, the plate cylinder 7 passes an ink supply part 6 and ink is applied to the magnetic fine powder fixing part of the plate cylinder 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an offset printing press that is plateless.

(Prior art) Conventionally, when offset printing a digital image with an offset printing machine, a planographic plate is manufactured from aluminum or the like using a plate making machine, and the planographic plate is mounted on the plate cylinder of the offset printing machine to print the digital image. I am trying to print images offset.

(Problems to be Solved by the Invention) Conventionally, when offset printing a digital image using an offset printing machine, a planographic plate is produced from aluminum or the like using a plate making machine as described above.

The lithographic plate is attached to the plate cylinder of an offset printing machine to offset print digital images, so (
I) It required a lot of time and money to produce a planographic plate. (II) It took a lot of time to attach the lithographic plate to the plate cylinder. (I [[) In the case of multicolor printing, color misalignment may occur depending on the circumstances when mounting the plano, and registration work is required to correct it. (TV) With small loft printing, it was difficult to perform offset color printing, so only monochrome printing was performed.

(V) Since dampening water was used, problems such as emulsification of the ink occurred.

(Means for Solving the Problems) The present invention addresses the above-mentioned problems, and includes a magnetic drum having a magnetic material on its outer surface, and an outer surface of the magnetic drum that corresponds to the image area magnetized. a magnetic head that forms a magnetic latent image; a fine powder supply section that supplies magnetic fine powder containing a fixing agent and whose surface has been subjected to ink-phobic treatment to the magnetized image area; an ink supply section that supplies ink to the magnetic fine powder fixing section of the plate cylinder; a cleaning section that removes the magnetic fine powder from the surface of the plate cylinder; It is characterized by comprising a demagnetizing head that demagnetizes the magnetism of the drum.

The purpose of the present invention is to make it possible to use a non-printing plate.

Printing can be performed directly on printing paper based on digital image data. Furthermore, since a lithographic plate is not required, the production and installation work of a lithographic plate can be eliminated, and the expenses required for this can be reduced. Also, registration can be achieved by electrical processing. Also, offset color printing can be performed even in small lot printing. Furthermore, it is an object of the present invention to provide an improved offset printing machine that can eliminate problems such as emulsification of ink caused by the use of dampening water.

(Function) The offset printing press of the present invention is constructed as described above, in which the outer surface of the magnetic drum corresponding to two print areas is magnetized by a magnetic head.

After forming a magnetic latent image, firstly, magnetic fine powder containing a fixing agent and whose surface has been subjected to an ink-phobic treatment is transferred from a fine powder supply section to a plate cylinder whose surface has been subjected to an ink-phobic treatment, and is fixed thereon. The ink is supplied from the supply section to the magnetic fine portion of the plate cylinder, then transferred to the blanket roll, and then supplied from the printing paper supply section between the blanket roll and the impression cylinder to be transferred to the printing paper passing between them. and print. When printing is finished, the cleaning section sprays a solvent onto the plate cylinder to remove the magnetic fine powder and fixing agent on the second plate cylinder, returning the outer surface of the third plate cylinder to its original ink-phobic property, and The upper magnetic latent image is demagnetized by a demagnetizing head.

(Example) Next, the offset printing press of the present invention will be explained using an example shown in FIG. 1. (1) is a magnetic drum.

The outer surface of the magnetic drum (1) is treated with a wear-resistant material, and the lower layer is a magnetic material.

For example, C, -N, alloy thin films are undercoated. In addition, (2) is a magnetic head, which partially magnetizes the outer surface of the magnetic drum (1) in response to image data sent from an image data calculation section (12) to be described later. (3) is a demagnetizing head for demagnetizing the magnetic latent image on the magnetic drum (1);
(4) is a fine powder supply section, and the fine powder supply section (4) is composed of a magnetic roll, etc. used in copying machines, etc., and contains a fixing agent and has an ink-philic treatment on its surface. Fine powder is supplied onto a magnetic drum (1). In addition, (5) is a magnetic fine powder removing device that removes magnetic fine powder on the plate cylinder (7) that has been transferred and fixed from the magnetic drum (1). It consists of a solvent application section for applying a solvent that melts the magnetic powder, and a suction section that attracts the solvent and magnetic powder. Further, (6) is an ink supply section, which supplies ink to the magnetic fine powder fixing section of the plate cylinder (7) to form nine print areas. In addition, the surface of the plate cylinder (7) is treated with silicone (ink-phobic), and the ink-philic magnetism transferred from the magnetic drum (1) and fixed on the surface of the plate cylinder (7) is applied. The fine powder is fixed to form one drawing area. Also, (8) is a blanket roll, (9) is an impression cylinder, and (10) is a printing paper supply section.

(11) transfers the magnetic fine powder on the magnetic drum (1) to the plate cylinder (7).
This is a magnetic fine powder fixing unit roll that fixes the fine powder onto the top using pressure or heat. In addition, the magnetic head (2) and the demagnetizing head (3)
When the magnetic drum (1) is rotating.

A serial type that magnetizes and demagnetizes while moving the head parallel to the drum rotation axis, or a fixed head with the same length as the drum rotation axis.

There are line types that perform magnetization and demagnetization by electrically scanning. Also in FIG. 2, which shows a four-color full-color magnetic offset printing machine.

(12) is an image data calculation section;
teeth.

A function that accepts image data sent from color scanners, magnetic disks, image transmission devices, etc., and divides and calculates each data separated into four primary colors, including black, into the appropriate number of pixels and gradations. have. Then, image signals are sent to magnetic heads (2) corresponding to each primary color.

Next, the operation of the offset printing press shown in FIGS. 1 and 2 will be explained in detail. First, the image data calculation unit (12
) is the digital image data entered into.

It is divided into data corresponding to the primary colors of cyan, magenta, yellow, and black. Further, the divided data of each color is arithmetic processed so that it is expressed by the number of pixels of 166 pixels per 1 mm, and each pixel is also expressed by the number of gradations of 64 or more gradations. Next, the procedure for forming a magnetic latent image on the outer surface of the magnetic drum (1) will be explained. First, the entire surface of the magnetic drum (1) is the degaussing head (3).
It is demagnetized by What part of the magnetic drum (1) should be magnetized?

Since the image data is an image area, the above image data is converted into image area data to be magnetized, and then data corresponding to the three image areas is sent to the magnetic head (2), and the image data on the magnetic drum (1) is converted into image area data. The part corresponding to the part is magnetized. (Non-image areas are not magnetized). As another method.

There is a method of magnetizing the entire surface of the magnetic drum (1) and demagnetizing only the non-image areas. Next, the process of supplying magnetic fine powder and fixing it begins. First, when the magnetized outer surface of the magnetic drum (1) passes through the fine powder supply section (4), it contains a fixing agent and is subjected to an ink-philic treatment on the surface. The magnetic fine powder obtained is supplied to the magnetic drum (1).

The magnetic fine powder is attached and held only on the magnetic latent image portion by its magnetic force, and then the magnetic fine powder is brought into contact with the plate cylinder (7).

At this time, electrostatic electrolysis or a reverse magnetic field is applied.

The magnetic fine powder is transferred to the plate cylinder (7). The magnetic fine powder transferred to the plate cylinder (7) is fixed on the surface of the plate cylinder (7) which has been treated with silicon (ink-phobic) by a magnetic fine powder fixing roll (11). Magnetic fine powder is a ferromagnetic material such as ferrite, manganese-zinc ferrite, manganese-nickel ferrite magnetite, nickel, and permalloy, and preferably has high magnetic permeability and a particle size of 10 microns or less, and is suitable for use in fixing resins, etc. Magnetic fine powder containing a fixing agent and whose surface has been treated with ink-phobic (silicon) treatment is desirable.

There are pressure fixing methods, heat fixing methods, and the like for fixing magnetic powder. That is, the pressure fixing method is a method of fixing magnetic powder containing resin and wax on a magnetic latent image area by mechanically pressing it with a roller, and examples of the pressure fixing resin include polyethylene resin and polyester resin.

Polyamide resin, modified rosin ester resin.

Polystyrene resin, styrene-acrylic copolymer.

There are polycarbonate resins, etc. Also, what is the heat fixing method?
The magnetic fine powder containing the resin on the magnetic latent image is heated to about 110°C to 170' using a heating roller, oven heater or laser.
This is a method of fixing by heating the resin to c and fusing the resin, and is one of the heat fixing resins.

The resin for open heaters is styrene resin.

There are epoxy resins, polyester resins, polyamide resins, etc. The resin for the heating roller is styrene resin, polyester resin, acrylic acid or methacrylic acid, and long-chain alkyl acrylate.

Examples include copolymers with long-chain alkyl methacrylates, copolymers with styrene and long-chain alkyl acrylates, copolymers with long-chain alkyl methacrylates, and polyolefin resins. When the above-mentioned magnetic powder supply and fine powder fixing steps are completed, the printing process begins, where the plate n port (7) first passes through the ink supply section (6) and ink is applied to the magnetic fine powder fixing section of the first plate cylinder (7). is coated. Ink does not adhere to other parts (non-printing parts) because the surface of the first plate cylinder (7) is made of ink-phobic silicon.

This allows it to perform the same function as a conventional offset printing plate. That is, the ink in the image area on the outer surface of the 9th plate cylinder (7) is transferred to the outer surface of the blanket roll (8), and is then sent from the printing paper supply section (1o) and pressed against the blanket roll (8). It is transferred to the printing paper passing between the cylinder (9) and printing is performed. When the printing process is finished, the cleaning section (5) injects a solvent for removing the magnetic powder and fixing agent onto the plate cylinder (7) and sucks the magnetic powder.

The entire outer surface of the plate cylinder (7) is returned to its original ink-phobic property.

In addition, the magnetic latent image on the magnetic drum (1) is removed by the degaussing head (3).
Demagnetize by

(Effects of the Invention) As described above, the offset printing press of the present invention magnetizes the outer surface of the magnetic drum corresponding to one image area with the magnetic head to form a magnetic latent image.

Next, the magnetic fine powder containing a fixing agent and whose surface has been subjected to an ink-phobic treatment is transferred from the fine powder supply section to the plate cylinder whose surface has been subjected to an ink-phobic treatment and fixed. Supply to minute parts.

Next, this ink is transferred to the blanket roll, and then supplied from the printing paper supply section to between the blanket roll and the impression cylinder, and transferred to the printing paper passing between them to perform printing. When printing is finished, the cleaning section sprays solvent onto the plate cylinder.

The magnetic fine powder and fixing agent on the plate cylinder are removed to return the outer surface of the plate cylinder to its original ink-phobic properties, and the magnetic latent image on the magnetic drum is demagnetized by the demagnetizing head.

Printing plates can be used, and printing can be performed directly on printing paper based on digital image data. Furthermore, since a lithographic plate is not required, the production and installation work of a lithographic plate can be eliminated, and the costs required for this can be reduced.

Also, registration can be achieved by electrical processing. Also, offset color printing can be performed even in small lot printing. Furthermore, it has the effect of eliminating problems such as emulsification of ink that occurs when using dampening water.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of an offset printing machine according to the present invention, and FIG. 2 is an explanatory diagram showing the relationship among a printing device, a magnetic drum, and an image data calculation section. (1)...Magnetic drum, (2)...Magnetic head, (
3)... Demagnetizing head, (4)... Magnetic powder supply section,
(5)...Cleaning section, (6)...Ink supply section. (7)...Print cylinder, (8)...Blanket roll. (9)...Impression cylinder, (10)...Printing paper supply section, (11)...Magnetic fine powder fixing roll, (12)
...Image data calculation section. Figure 1 Figure 2

Claims (1)

[Claims] A magnetic drum having a magnetic material on its outer surface, a magnetic head that magnetizes the outer surface of the magnetic drum corresponding to the image area to form a magnetic latent image, and a fixing agent and an ink-philic treatment applied to the surface. a fine powder supply section that supplies the magnetic fine powder to the magnetized image area, a transfer/fixing section that transfers and fixes the magnetic fine powder onto a plate cylinder that has been subjected to an ink-phobic treatment, and a magnetic fine powder fixing unit on the plate cylinder. 1. An offset printing machine comprising: an ink supply section that supplies ink to the plate cylinder; a cleaning section that removes magnetic fine particles from the surface of the plate cylinder; and a demagnetization head that demagnetizes the magnetic drum.