JP3329657B2 - Method for preventing printing stains on newspaper offset rotary printing press and dummy plate for preventing printing stains used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset rotary printing press having a color printing unit in the field of newspaper printing, in which printing is performed with a smaller number of colors than the maximum number of colors of the unit. The present invention relates to a method for preventing the occurrence of print stains and a dummy plate for preventing print stains used therefor.

[0002]

2. Description of the Related Art In the field of newspaper printing, the number of pages (in pages) of a newspaper to be published often fluctuates. I have. For this reason, when printing is performed with a small number of pages or color pages, a situation occurs in which a plate cylinder of a certain color printing unit is not used for printing but paper is passed. At this time, if the printing is performed as it is, excess stain is printed on the passing paper through the plate cylinder. Therefore, when printing only the unused plate cylinder, for example, only black, the other three colors (cyan, magenta, yellow) are used. ), A printing plate called a blank plate, which is a non-image portion on the entire surface, is attached to prevent generation of stains.

[0003]

At present, as a stencil printing plate, a lithographic printing plate having no photosensitive layer coated thereon, that is, an aluminum plate having a hydrophilic surface, is prepared by using a PS plate automatic plate making apparatus. It is common practice to carry out the process in the same manner as described above and use it in a state where it can be mounted on a printing press. The purpose of this is to reduce the overall printing cost as much as possible by using a lithographic printing plate as a blank plate, which is somewhat less expensive than the PS plate because the photosensitive layer is not coated.

[0004] However, with the recent colorization of newspapers, the number of situations described above has increased, such as the increase in the number of color printing units installed in rotary printing presses, and the number of blank plates has also increased. However, since the support is made of aluminum, cost reduction cannot be expected so much that economic efficiency is a problem.

[0005] In view of the above facts, the present invention provides an inexpensive PE.
It is an object of the present invention to provide a method for preventing printing stains generated in a color printing unit that does not perform color printing by using a dummy plate having a T film as a support, and a printing stain preventing dummy plate used for the method.

[0006]

The above object is achieved by the following means. That is, in a color printing unit of an offset rotary printing press for newspaper printing, when printing is performed with a smaller number of colors than the maximum number of colors that the printing unit has, a corona discharge process is applied to the plate cylinders other than the printing color.
And / or latex coating treatment.
This can be achieved by mounting and printing a PET film provided with a hydrophilic layer made of an adhesive. As a result, it is possible to prevent the occurrence of printing stains on the plate cylinder of a color not used for printing, and to obtain the effect of reducing costs as compared with the case of using an aluminum blank plate.

Further, a corona discharge treatment and / or a latte
Surface coated with an organic binder
By using a PET film formed by pressurizing under heating conditions, the folded part for mounting the printing machine on the PET film provided with the conductive layer is effective for printing on a rotary offset press for newspaper rotating at high speed. , A dummy plate for preventing printing stains can be attached.

[0008] Further, after the surface of the PET film is subjected to corona discharge treatment and / or treatment by latex coating, a hydrophilic layer made of an organic binder is provided.
Further, since the hydrophilic layer is composed of a plurality of layers, the organic binder contains at least one of gelatin, a polyvinyl alcohol-based composition, and a cellulose derivative. The at least one layer contains at least one of titanium oxide, silicon dioxide, and aluminum oxide, and the latex is a vinylidene chloride polymer and / or a copolymer thereof. After performing a treatment by corona discharge treatment and / or latex coating, a hydrophilic layer containing at least gelatin and titanium oxide is provided, and a dummy plate for preventing printing stains in which the weight ratio of gelatin to titanium oxide is 1: 2 or more is used. When used together, the characteristics are further improved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method for preventing printing stains according to the present invention, the layer structure of a dummy plate for preventing printing stains related to the method, and the method for manufacturing the same will be described in detail. The dummy plate according to the present invention uses a PET film as a support and has a corona
Update the surface after discharge treatment and / or latex coating treatment.
Has a hydrophilic layer made of an organic binder ,
Preferably, a bent portion is formed at both ends of the support for mounting on a rotary printing press by applying pressure in a heated state.

[0010] PE used for the dummy plate according to the present invention
The T film is a biaxially stretched polyester film, and any of a transparent film, a white film kneaded or coated with a white pigment, and a white film foamed and opaque can be used. The thickness is preferably thicker from the viewpoint of mechanical strength, but is preferably equal to or less than the thickness of the tailoring of the printing press, and the range of 50 μm to 300 μm is suitably used.

It is preferable to improve the hydrophilicity and adhesiveness of the surface by physicochemical treatment such as corona treatment, glow discharge treatment, plasma treatment, electron beam irradiation treatment, far ultraviolet irradiation treatment, and ozone treatment. It is also effective to improve the hydrophilicity and adhesiveness by providing a layer made of latex, vinyl chloride-based copolymer, vinylidene chloride-based copolymer, butadiene-based copolymer, methacrylic acid and acrylic acid and It is preferable to apply a latex such as an ester-based copolymer, and the method of applying the latex is described in U.S. Pat.
The method according to JP-A-0-213942 is preferred.

The hydrophilic layer used in the dummy plate according to the present invention comprises an organic binder composed of a high molecular compound, that is, a natural polymer, a semi-natural product (semi-synthetic product), a synthetic product or the like. A layer (film) is formed on the surface of the treated PET film, and more preferably, an inorganic substance such as titanium oxide, silicon dioxide, and aluminum oxide is used in combination. These may be contained in at least one layer as a plurality of layers.

Examples of natural polymers include those obtained from algae such as starches, seaweed mannan, seaweed, agar and sodium alginate, mannan, pectin, tragacanth gum, karaya gum, xanthin gum, guaring gum, locust bingham, gum arabic and the like. Plant mucilage, dextran, glucan, xanthan gum, homopolysaccharides such as levan, and microbial mucilage such as heteropolysaccharides such as succinoglucan, pullulan, curdlan, and xanthan gum; glue, gelatin, casein, collagen, etc. And chitin and its derivatives.

Further, as semi-natural products (semi-synthetic products),
Examples include cellulose derivatives, modified gums such as carboxymethyl guar gum, and modified starches such as baked starches such as dextrin, oxidized starches, and esterified starches.

As synthetic products, polyvinyl alcohol,
Modified polyvinyl alcohol such as partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, polyacrylate, partially acrylated polyacrylate, polymethacrylate, and polyacrylamide Such as polyacrylic acid derivatives and polymethacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone,
Examples include vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer, styrene / crotonic acid copolymer and the like.

Among them, gelatin, polyvinyl alcohol-based compositions which are modified and unmodified polyvinyl alcohol, and cellulose derivatives can be advantageously used.

As the gelatin used in the hydrophilic layer of the dummy plate according to the present invention, any gelatin can be used as long as it is made of animal collagen. Collagen obtained from pig skin, cow skin and cow bone is used as the raw material. Gelatin is preferred. There is no particular limitation on the kind of gelatin, but in addition to lime-treated gelatin and acid-treated gelatin,
No. 854, No. 39-5514, No. 40-12237
And No. 42-26345, U.S. Pat.
No. 25,753, No. 2,594,293, No. 2,61
No. 4,928, No. 2,763,639, No. 3,11
No. 8,766, No. 3,132,945, No. 3,18
6,846, 3,312,553 and British Patent 1,033,189, etc., and these may be used alone or in combination of two or more. Can be used.

When gelatin is used as the hydrophilic layer, it can be cured with a gelatin hardener. Examples of gelatin hardeners include inorganic compounds such as chrome alum, aldehydes such as formalin, glyoxal, malealdehyde and glutaraldehyde, N-methylal compounds such as urea and ethylene urea, mucochloric acid, 2,3 Aldehydes such as dihydroxy-1,4-dioxane, 2,4-dichloro-6-hydroxy-
Compounds having an active halogen such as S-triazine salt, 2,4-dihydroxy-6-chloro-S-triazine salt, divinyl sulfone, divinyl ketone, N, N, N
One or a variety of compounds such as triacryloylhexahydrotriazine, compounds having two or more active three-membered ethyleneimino groups or epoxy groups in a molecule, dialdehyde starch as a polymer hardener, or Two or more types can be used.

The cellulose derivative used in the hydrophilic layer of the dummy plate according to the present invention includes propylene glycol alginate, viscose, methyl cellulose, ethyl cellulose, methyl ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose. , Hydroxypropylethylcellulose, carboxymethylhydroxyethylcellulose,
And hydroxypropyl methylcellulose phthalate. The molecular weight of the cellulose derivative used in the present invention is preferably up to about 150,000, and the degree of etherification is 1
% Is preferable. Cellulose derivatives having a molecular weight exceeding 150,000 or having a degree of etherification of 1%
If it exceeds, the viscosity increases during the preparation of the solution, and the coating properties and the like deteriorate. Therefore, in order to adjust the film properties, liquid preparation properties, and coating properties, two or more cellulose derivatives having different molecular weights or different degrees of etherification may be used in combination.

The hydrophilic layer of the dummy plate according to the present invention may contain a mixture of gelatin and a cellulose derivative.
There is no particular limitation on the mixing ratio.

In the hydrophilic layer of the dummy plate according to the present invention,
An inorganic substance such as titanium oxide, silicon dioxide, and aluminum oxide can be contained for the purpose of improving the stain resistance to printing. The proportion to be contained is appropriately determined in a desired range depending on various conditions such as printing ink and fountain solution used for printing, printing speed, printing pressure, etc., and is contained at a weight ratio of 1: 2 or more with respect to the organic binder. Is preferred.

The titanium oxide used in the hydrophilic layer of the dummy plate according to the present invention may be a powdery one or a titanium oxide dispersed in a deflocculant or a polymer stabilizer. Examples of commercially available powdered products include TT0-55 manufactured by Ishihara Sangyo Co., Ltd.
FTL-100, TA-100, TA made by Fuji Titanium Industry
-200, TA-300, TR-700, TR-75
0, TR-840 and the like. In the case of a dispersion, titania sols CS-C and CS-N manufactured by Ishihara Sangyo are listed.

As the silicon dioxide used for the dummy plate according to the present invention, a powdery one or a colloidal colloidal silica can be used. Examples of commercially available powdered products include Carplex FPS-1, F
PS-4, FPS-101, Fuji Silysia Chemical Sylysia 250, Sylysia 310, Sylysia 430, Sylysia 530, and Sylysia 730. As the colloidal silica used in the present invention, any of unmodified silica and modified colloidal silica in which the surface of the silica is coated with ions or compounds such as calcium and alumina to change the ionicity and the behavior with respect to pH fluctuation may be used. Can be.
Examples of commercially available colloidal silica used in the present invention include:
Nissan Chemical Industries Snowtex 20, Snowtex N, Snowtex O, Snowtex S, Snowtex 20L, Snowtex AK, and Snowtex UP, etc., Nippon Chemical Industries silica doll 20, silica doll 20A, silica doll 20G, And Silica Doll 20
P, Adelite AT-20, Adelite AT-20N, Adelite AT-30A and Adelite AT-20Q manufactured by Asahi Denka Kogyo, Ludox HS-3 manufactured by DuPont.
0, Ludox LS, Ludox SM-30, Ludox AS, and Ludox AM.

The aluminum oxide used for the dummy plate according to the present invention may be either powdery or colloidal. Colloidal alumina is
It is a colloidal substance of boehmite-type or pseudo-boehmite-type alumina having a so-called feather-like, fibrous, or flat-plate-like shape. Examples of commercially available colloidal alumina according to the present invention include alumina sol-10, alumina sol-20, alumina clear sol, alumina sol-SH5, and alumina sol-CSA5 manufactured by Kawaken Fine Chemicals.
5, alumina sol-SV102, and alumina sol-S
B52, Cataloi, manufactured by Catalysis Chemical Industry
d) -AS (AS-1, AS-2, AS-3) and Cataloid AP, and Nissan Chemical Industries alumina sol-10
0, alumina sol-200, and alumina sol-520
And the like.

The hydrophilic layer of the dummy plate according to the present invention can be obtained by coating an aqueous liquid containing an organic binder such as gelatin and / or an inorganic substance such as titanium oxide on a PET film. In order to adjust the viscosity, coating properties, coating liquid stability, etc. of the coating liquid, a desired amount of a solvent miscible with the aqueous coating liquid may be added to the forming coating liquid. As the miscible solvent used in the present invention, alcohols such as methanol, ethanol, 1-propanol and 2-propanol, ketones such as 2-propanone and 2-butanone,
Examples thereof include ethers such as 1,3-dioxolan, 1,4-dioxane, 1-methoxy-2-propanol, and 2-ethoxyethanol.

A surfactant may be further added to the coating liquid for forming a hydrophilic layer of the dummy plate according to the present invention. The surfactant used may be any of anionic, cationic, nonionic, and betaine systems, and may be of low molecular weight or high molecular weight. These may be used alone or in combination of two or more. In particular, when two or more kinds are used in combination, for example, when separately preparing a colloidal silica-containing liquid and another hydrophilic layer component-containing liquid, a separate surfactant is used, and finally each liquid is used. They may be mixed to form a coating liquid for forming a hydrophilic layer. The amount of the surfactant to be added to the coating liquid for forming a hydrophilic layer is preferably from 0.01 to 5% by weight, more preferably from 0.05 to 3% by weight, based on the total solid content of the hydrophilic layer.

Further, in addition to the above components, an inorganic (white) pigment having no film forming ability,
Coloring dyes, coloring pigments, ultraviolet absorbers, antioxidants, antifoaming agents, leveling agents, preservatives, fluorescent brighteners, thickeners, and various additives such as pH adjusters are added in appropriate combinations. Is also good.

Examples of the method for applying the hydrophilic layer according to the present invention include a slide popper method, a curtain method, an extrusion method, an air knife method, a roll coating method, a rod bar coating method, and a gravure coating method. The amount of the solid content applied to the hydrophilic layer according to the present invention is not particularly limited, but is preferably about 0.1 to 40 g / m ² from the viewpoint of dampening water absorption and blocking properties.

The hydrophilic layer according to the present invention may be formed as a plurality of layers of different types from the above-mentioned organic binders for the purpose of improving the adhesion to the PET film.

As a bending method for mounting the dummy plate according to the present invention on a rotary printing press, a fold is formed on the dummy plate, the fold is overlapped through the fold, and the fold is heated in the overlapped state. It can be bent by applying pressure. As a bending device for performing such bending, a jig described in Japanese Patent Application Laid-Open No. 62-152856, a plate bending device described in Japanese Patent Application Laid-Open No. 2-102499, and the like can be used. By using these,
The plate can be simply and sufficiently bent and the bent angle can be maintained, and the plate can be effectively attached to a rotary press for newspaper rotating at high speed.

Further, some rotary presses have a pin at a bent portion for positioning. In this case, before forming the bent portion of the dummy plate, a cutout portion corresponding to the rotary press positioning pin is opened. It can be provided by a punch device.

[0032]

EXAMPLES The method for preventing printing stains and the dummy plate for preventing printing stains used therein according to the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

Example 1 The surface of a PET film having a thickness of 175 μm was subjected to a corona discharge treatment, and gelatin was immediately used as a hydrophilic layer in a solid content of 2%.
g / m ² and dried to produce a dummy plate A. Both ends of the dummy plate A were bent by the following method to form a bent portion for mounting on a rotary press.

<Method of Forming Folded Parts> As shown in FIG. 1, the dummy plate 1 is placed on the plate holder 3 and the rotary bending tool 4 whose contact portions 31 and 41 are heated to about 60 ° C. by the heater 7 and the pedestal 6. Is introduced between the inner movable blade portions 2, and the dummy plate 1 is fixed with the plate holder 9. Next, as shown in FIG. 2, the rotary bending tool 4 is rotated by the rotary bending tool lever 8 along the dummy plate 1 along the inner movable blade portion 2, and the dummy plate 1 is creased. Subsequently, as shown in FIG. 3, the contact portion 31 of the plate holder 3 and the contact portion 41 of the rotary bending tool 4 are slid so as to come into contact with the fold of the dummy plate. Further, after the inner movable blade portion 2 is retracted by a moving means (not shown) so that the rotary bending tool 4 can rotate, as shown in FIG.
Is sandwiched between the plate holder 3 and the rotary bending tool 4 and pressurized to form a bent portion.

The dummy plate A produced as described above is mounted on unused color cylinders of yellow (Y), magenta (M) and cyan (C) in a color printing unit of a rotary printing press. When printing was performed with the PS plate mounted on only the black (K) plate cylinder, printed matter free of Y, M, and C colors was obtained from the start of printing. However, during printing 100
From around the 00th sheet, dirt of each color of Y, M, and C gradually appeared slightly.

Example 2 The surface of a PET film having a thickness of 175 μm was subjected to a corona discharge treatment, and an undercoating liquid having the following composition was immediately applied as a hydrophilic layer to a solid content of 10 mg / m ² and dried. On this subbing layer, a commercially available gelatin made from bovine bone was applied so as to have a solid content of 2 g / m ² and dried to prepare a dummy plate B.

<Undercoat liquid composition> A copolymer emulsion having a monomer molar ratio of styrene: 2-ethylhexyl acrylate: acrylic acid = 40: 58: 2 20 ml butyl carbitol acetate (10% alcohol solution) 5 ml ethylene glycol di Glycidyl ether (10% alcohol solution) 10 ml Na dodecylbenzenesulfonate (10% aqueous solution) 3 ml Add water to 1 L or more.

The dummy plate B obtained as described above was formed with bent portions at both ends in the same manner as in Example 1, and printing was performed. Obtained from the start-up, no smear of each color of Y, M and C was observed even on about 10,000 sheets during printing. However, during printing, some stains of each color gradually appeared from about 50,000 sheets.

Example 3 A commercially available PET film (manufactured by Dupont, product name: Cloner) having a 175 μm-thick surface hydrophilized with a latex made of a vinylidene chloride copolymer compound was further used as a hydrophilic layer having the following composition. A coating solution was prepared and applied so that the amount of moisture applied was 42 g / m ^2.
Was prepared.

<Coating Composition> Parts by weight Gelatin (manufactured by Nitta Gelatin; IK Gelatin) 3.5 Silicon dioxide (manufactured by Shionogi & Co .; Carplex FPS-101) 1.2 Formaldehyde (30% aqueous solution) 1.0 Glyoxal ( 30% aqueous solution) 1.0 Surfactant 1.0 Water 92.3

The dummy plate C obtained as described above was formed with bent portions at both ends in the same manner as in Example 1, and printing was performed. Standing up, Y,
No stain of each color of M and C was observed. However, during printing, stains of each color gradually appeared from about 70,000 sheets.

Example 4 A commercially available PET film (manufactured by Dupont, product name: Cloner) having a 175 μm-thick surface hydrophilized with a latex made of a vinylidene chloride copolymer compound was further used as a hydrophilic layer having the following composition. A coating solution was prepared and applied so that the amount of moisture applied was 42 g / m ^2.
Was prepared.

<Coating Composition> Parts by weight Gelatin (manufactured by Nitta Gelatin; IK Gelatin) 3.5 Silicon dioxide (manufactured by Shionogi & Co .; Carplex FPS-101) 10 Formaldehyde (30% aqueous solution) 0.5 Glyoxal (30%) Aqueous solution) 1.0 surfactant 1.0 water 84

The obtained dummy printing plate D was formed with bent portions at both ends in the same manner as in Example 1, and printing was performed. Smear of each color of Y, M and C was not observed even on about 100,000 sheets during printing.

[0045]

According to the present invention, there is provided an offset rotary printing press having a color printing unit in the newspaper printing field.
When printing is performed with a smaller number of colors than the maximum number of colors of the unit, it is possible to prevent printing stains generated in the color printing unit. Also, by using the dummy plate of the present invention, the PS plate can be used as a non-image portion on the
The cost is lower than that using an aluminum plate not coated with a plate photosensitive layer. Further, since the bent portion is formed by the heat treatment, printing can be performed without dropping from the rotary press even when performing high-speed printing on the rotary press.

[Brief description of the drawings]

FIG. 1

FIG. 4 is a schematic sectional view showing an embodiment of forming a bent portion of a dummy plate according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dummy plate 2 Inner movable blade part 3 Plate holder 4 Rotating bending tool 6 Pedestal 7 Heater 8 Rotating bending tool lever 9 Plate holding tool 31 Contact part (of plate holding tool 3) 41 Contact part of (rotation bending tool 4)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-175090 (JP, A) JP-A-7-149072 (JP, A) JP-A-7-144487 (JP, A) JP-A-5- 193282 (JP, A) JP-A-2-102049 (JP, A) JP-A-56-152112 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41N 1/12-1 / 14 B41F 7/20 B41F 27/00

Claims (7)

(57) [Claims] In a multi-color printing unit of a web offset press for newspaper printing, when printing is performed with a smaller number of colors than the maximum number of colors of the printing unit, a corona discharge is applied to a plate cylinder on which printing is not performed. A method for preventing printing stains, further comprising mounting a PET film provided with a hydrophilic layer made of an organic binder on a surface subjected to the treatment and / or the latex coating treatment. 2. A folded portion for mounting a printing machine on a PET film provided with a hydrophilic layer made of an organic binder on a surface subjected to a corona discharge treatment and / or a latex coating treatment is added under heating. 2. The method according to claim 1, wherein the method is formed by pressing. 3. A printing stain prevention method according to claim 1 or 2, wherein the hydrophilic layer is composed of a plurality of layers. 4. An organic binder comprising at least one of gelatin, a polyvinyl alcohol-based composition, and a cellulose derivative.
The method according to any one of claims 1 to 3, wherein the method comprises the steps of: At least one layer of 5. A hydrophilic layer, titanium oxide, silicon dioxide, of aluminum oxide, the printing according to any one of claims 1 to 4, characterized in that it contains at least one How to prevent dirt. 6. A latex is characterized in that the vinylidene chloride polymer and / or copolymer thereof according to claim 1
Or the method for preventing printing stains according to 2. 7. A hydrophilic layer is provided on a PET film which has been subjected to corona discharge treatment and / or latex coating treatment,
A dummy plate for preventing printing stains, wherein the hydrophilic layer contains at least gelatin, at least one of titanium oxide, silicon dioxide, and aluminum oxide, and the weight ratio of gelatin to them is 1: 2 or more.