JP2005250301A - On-demand print paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-demand print paper for use in an electrophotographic system, which has satisfactory printing quality, toner fixability, and conveyability in a printer and less dirties a head fixing roller in the printer. <P>SOLUTION: The on-demand print paper has a coating layer having a pigment and a binder as main components, provided on at least one surface of a base, and ≥20 mass% pigment in the coating layer is synthetic silica, and the Beck smoothness of the coating layer surface is 30 to 1000 seconds. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to an electrophotographic on-demand printing paper. In particular, the present invention relates to an on-demand printing paper for use in an electrophotographic system that has good print quality, toner fixability, and printer transportability and is less likely to cause contamination of a heat fixing roll inside the printer.

  As means for copying information to paper, there are a method using a printer or a copying machine suitable for one or several copies, and a method using a printing machine suitable for a large amount of copying. The printer is mainly used for outputting information of a personal computer or the like, and can freely output variable information different for each sheet. The copying machine and the printing machine are means for copying the information fixed on the document or the plate as they are in principle, and variable information cannot be added thereto. For this reason, when the number of copies is small, for example, about several hundred to several thousand, there is no suitable means for copying a small amount of variable information together with most of the fixed information.

  In recent years, computers and personal computers have been increased in speed, increased in capacity, and printers have been significantly increased in speed. As a result, it is possible to duplicate information consisting of fixed information and variable information in the number of hundreds to thousands. It became. This is called on-demand printing, in which digital information in a computer is directly printed on demand.

  On-demand printing is used for in-house magazines, various manuals, product catalogs, and so on. The recording principle of on-demand printing is the same as that of a printer or a printing machine, but it can be said to be faster and have better performance than a normal printer.

  On-demand printing is mainly divided into an electrophotographic method and an ink jet recording method, both of which are faster than conventional printers and printing machines. When coated paper used in conventional printers and printing presses is used for electrophotographic on-demand printing, a problem of toner fixing property and a problem of toner contamination of the heat fixing roll have occurred.

Developments have been made to solve the above problems. For example, JP-A-11-202536 discloses an electrophotographic image support having an image receiving layer on a substrate, and the image receiving layer contains a heat-meltable resin and a curable resin. ing. It is disclosed that the electrophotographic image support disclosed in the publication contains a heat-meltable resin and a curable resin in the image-receiving layer, and can prevent deterioration in color developability, transparency, and runnability. ing.
Japanese Laid-Open Patent Publication No. 5-241366 discloses an electrophotographic transfer paper in which a recording layer composed of a pigment and a binder is provided on a base paper having a specific range of smoothness and air permeability. . The electrophotographic transfer paper disclosed in this publication is disclosed to have a high white paper gloss and a high image gloss.

  When the electrophotographic image support and the electrophotographic transfer paper disclosed in the above publication are used for on-demand printing, the toner fixing property and the printer transportability can be improved to some extent, and the printing quality is also to some extent. It was thought that a good one could be obtained and the problem of smearing of the heat fixing roll inside the printer could be solved, but it was not sufficient.

JP-A-11-202536 JP-A-5-241366

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an on-demand printing paper for use in an electrophotographic system that has good print quality, toner fixing property, and printer transportability and is less likely to cause contamination of a heat fixing roll inside the printer. It is in.

  As a result of diligent studies to achieve the above object, the present inventor has found that a coating layer of an on-demand printing paper in which a coating layer mainly composed of a pigment and a binder is provided on at least one surface of a substrate. It was found that an on-demand printing paper containing synthetic silica and having a Beck smoothness on the surface of the coating layer in a specific range can achieve the above-mentioned object.

The present invention has been made on the basis of the above knowledge, and is an on-demand printing paper in which a coating layer mainly composed of a pigment and a binder is provided on at least one surface of a base material. On-demand printing paper is provided in which 20% by mass or more of the pigment in the layer is synthetic silica, and the Beck smoothness on the surface of the coating layer is 30 to 1000 seconds.
The on-demand printing paper has good print quality, toner fixability, and printer transportability, and is less likely to cause contamination of the heat fixing roll inside the printer.

The synthetic silica is preferably precipitated synthetic silica.
The average particle size of the synthetic silica is preferably 3 to 10 μm.
The content of the pigment in the coating layer of the on-demand printing paper is preferably 20 g or less per 1 m ^{2 of the} on-demand printing paper.
The pigment preferably contains talc, and the content of talc is preferably 5 to 80% by mass in the total mass of the pigment.

The on-demand printing paper of the present invention has good print quality, toner fixing properties and printer transportability, and is less likely to cause contamination of the heat fixing roll inside the printer.
Since the on-demand printing paper of the present invention is excellent in offset printing, it is particularly suitable as a printing paper for performing pre-printing with an offset printing machine and then printing with an electrophotographic printer. Further, it is particularly suitable as a printing paper for performing plateless printing with an electrophotographic full color printer.

The on-demand printing paper of the present invention will be described below.
The on-demand printing paper of the present invention is provided with a coating layer mainly composed of a pigment and a binder on at least one surface of a substrate.

First, the substrate used for the on-demand printing paper of the present invention will be described.
Examples of the substrate used in the present invention include paper and plastic, and these are preferably film-like. Specifically, in general, recording paper used in electrophotographic recording, thermal transfer paper used in thermal transfer recording, processed paper used in high-grade printing, fine coated paper, polyester film used in OHP, styrene-acrylic resin, etc. Transparent resin can be used.

In the on-demand printing paper of the present invention, when paper is used as a base material, hardwood kraft pulp, natural pulp, synthetic pulp or the like is used as a raw material. Any natural pulp can be used as long as it is usually used for papermaking. That is, examples include hardwood bleached kraft pulp, softwood bleached kraft pulp, hardwood unbleached kraft pulp, softwood unbleached kraft pulp, hardwood sulfite pulp, and conifer sulfite pulp. The main raw materials containing wood fibers are mechanically treated pulp and chips that are chemically treated with non-wood fibers such as kenaf, hemp, and straw, which are chemically processed pulps, and non-wood fiber materials. Virgin pulp, such as ground pulp, pulp that has been mechanically pulped with chemicals added to wood or chips, and semi-chemical pulp that has been digested to soften the chips and then pulped with a refiner Etc. are used to make paper. The paper is made using, for example, a paper machine such as a long paper machine, a twin wire paper machine, an on-top paper machine, a hybrid paper machine, or a round paper machine. When making paper, you may add the additive normally used when making paper to a pulp. Such additives include, for example, polyacrylamide, polyvinyl alcohol polymers, urea / formalin resin, melamine / formalin resin, paper strength enhancers such as starch; chemical fixing agents such as sulfuric acid bands, polyacrylamide, acrylamide / amino. Freeness or yield improver such as methyl acrylamide copolymer salt, cationized starch, polyethyleneimine, polyethylene oxide, acrylamide / sodium acrylate copolymer; rosin size, alkyl ketene dimer (AKD), alkenyl succinic anhydride Sizing agents such as (ASA); waterproofing agents such as polyamide, polyamine and epichlorohydrin; fillers such as antifoaming agents and talc; dyes; color pigments; antibacterial agents; Waste paper pulp may be blended in the raw material, and examples of the used paper pulp include pulp made from at least one selected from newspaper used paper, magazine used paper, and corrugated used paper. In addition, used leaflet paper, coated paper, non-coated paper, ground paper, color printed paper, black and white printed paper, or the like may be used.
The paper used may be neutral paper or acid paper.

  When paper is used as the base material, the paper is porous and liquid easily penetrates. Therefore, in order to uniformly and thinly apply a coating liquid for forming a coating layer described later, the paper is subjected to a sealing treatment. May be. The sealing treatment can be carried out by, for example, applying a coating solution in which polyethylene, clay, polyvinyl alcohol, starch, carboxymethyl cellulose, or the like is dissolved or dispersed in advance to paper and drying to form respective coatings. .

  Moreover, a plastic film can also be used as a base material. Examples of the plastic film include a polyester film, a polycarbonate film, a polystyrene film, a polyphenylene sulfide film, a polypropylene film, a polyimide film, and a cellophane produced by an acetate film, a cellulose triacetate film, a nylon film, and polyethylene terephthalate.

Next, the coating layer provided on at least one surface of the substrate in the on-demand printing paper of the present invention will be described.
The said coating layer has a pigment and a binder as a main component, and 20 mass% or more of the pigment in a coating layer is a synthetic silica. The proportion of synthetic silica is preferably 50% by mass or more. Examples of the synthetic silica include precipitated silica and gel synthetic silica. In the present invention, it is preferable to use precipitated synthetic silica from the viewpoint of toner fixability and prevention of fixing roll stains. Moreover, it is preferable that the average particle diameter of the synthetic silica used is 3-10 micrometers. If the average particle size of the synthetic silica is less than 3 μm, the price of the synthetic silica may increase and the price of on-demand printing paper may increase. On the other hand, if it exceeds 10 μm, the smoothness will be poor and the texture of the on-demand printing paper May get worse.

  In general coated paper and art paper, quality design is made with an emphasis on proper offset printing with clay and calcium carbonate as the main pigments. When such general coated paper or art paper is used in an electrophotographic printer for on-demand printing, troubles such as toner fixing failure and printer conveyance failure are likely to occur. For this reason, conventionally, non-coated paper has been used in electrophotographic on-demand printing. On the other hand, synthetic silica is used for ink jet recording paper and the like, but generally used synthetic silica is porous and has high oil absorption. For this reason, if coating-type inkjet recording paper coated with synthetic silica is used for electrophotographic on-demand printing, the inside of the printer may become dirty, the print density may be low, and problems such as poor conveyance may occur. It becomes easy. Then, the compounding ratio etc. of synthetic silica were examined and it reached the present invention.

  20% by mass or more of the pigment in the coating layer is silica. Accordingly, the coating layer may contain a pigment other than silica. Examples of the pigment other than silica include talc, white carbon, kaolin, light calcium carbonate, magnesium carbonate, barium persulfate, and aluminum silicate. , Magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, composite of alumina and silica, zeolite, diatomaceous earth, magnesium hydroxide, hydroxyapatite, mica, titanium dioxide, clay, zinc oxide, lead titanate, etc. Be

Among the pigments, talc is preferably used from the viewpoint of improving printer transportability when used in a cut paper printer. In particular, it is preferable because continuous printing quality can be obtained which can prevent paper feed failure and jamming in a cut paper printer. When talc is used as the pigment, the content of talc is preferably 5 to 80% by mass, more preferably 10 to 50% by mass, based on the total mass of the pigment. If the talc content is less than 5% by mass based on the total mass of the pigment, the above-mentioned effect may not be exhibited. On the other hand, if it exceeds 80% by mass, the whiteness of on-demand printing paper may be reduced, Appropriateness may deteriorate.
Moreover, it is preferable that the average particle diameters of pigments other than synthetic silica are 3-10 micrometers similarly to synthetic silica.

Examples of the binder contained in the coating layer include polyvinyl alcohol, styrene-butadiene latex, urethane resin, vinyl acetate, ethylene vinyl acetate, acrylic resin, starch, casein, polyvinyl acetal, oxidized starch, etherified starch, and carboxy. Methyl cellulose, hydroxyethyl cellulose, casein, gelatin, soy protein, polyethylene imide resin, polyvinyl pyrohydrin resin, polyacrylic acid or copolymer thereof, maleic anhydride copolymer, acrylamide resin, acrylate ester resin, Polyamide resin, polyurethane resin, polyester resin, polyvinyl butyral resin, alkyd resin, epoxy resin, epichlorohydrin resin, urea resin, melamine resin, methyl methacrylate -Acrylic polymer latex such as butadiene copolymer, acrylic ester, methacrylic ester polymer or copolymer, resin of vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. . The said binder may be used independently and may mix and use 2 or more types.

The said coating layer is obtained by apply | coating the coating liquid containing the said pigment and a binder on a base material, and drying.
The blending ratio of the inorganic pigment and the binder in the coating liquid is preferably about 10 to 100 parts by mass of the binder with respect to 100 parts by mass of the pigment. When the proportion of the binder is less than 10 parts by mass with respect to 100 parts by mass of the pigment, the surface strength may be reduced. On the other hand, when the amount is more than 100 parts by mass, the opacity of the on-demand printing paper is reduced and the toner fixing property is reduced. May decrease.

You may add a various adjuvant to a coating liquid as needed. Auxiliaries include, for example, dispersants, lubricants, waxes, viscosity modifiers, antioxidants, fluorescent dyes, colored dyes, colored pigments, antistatic agents, surface electrical resistance control agents, water retention agents, thickeners, erasing agents. Examples include foaming agents, preservatives, dyes, water-proofing agents, fluorescent dyes, preservatives, ultraviolet absorbers, mold release agents, lubricants, and organic cation agents.
Although there is no restriction | limiting in particular as a coating method of a coating liquid, For example, it can coat using well-known coating machines, such as an air knife, a roll coater, a bar coater, a comma coater, a blade coater. The coating amount of the coating liquid on a solid basis of the pigment, and a 20 g / ^{m 2} or less, still more preferably from 3 to 15 g / ^{m 2.} That is, it is preferably applied so that the content of the pigment in the coating layer is 20 g or less per 1 m ^{2 of} on-demand printing paper, and more preferably ^{3 to} 15 g per 1 m ² . If the content of the pigment in the coating layer is less than the above range, the appearance of printing and the texture of the on-demand printing paper may be lowered. On the other hand, if the content exceeds the above range, the printer transportability is lowered. There is a case.

The coating solution is usually prepared as an aqueous coating solution.
After coating the coating liquid, the coating liquid is dried to form a coating layer, but the drying method in this drying process is not particularly limited, and examples include infrared drying, hot air drying, and room temperature drying. The drying method can be appropriately selected and used.
The coating layer obtained as described above is provided on at least one surface of the base material, but may be provided on both surfaces. Moreover, although a coating layer may be provided only in one layer, you may provide two or more layers.

The smoothness of the coating layer surface of the on-demand printing paper of the present invention is 30 to 1000 seconds, preferably 50 to 500 seconds. If the Beck smoothness on the surface of the coating layer is less than 30 seconds, uneven printing tends to occur, and the print quality deteriorates. On the other hand, if the Beck smoothness on the surface of the coating layer exceeds 1000 seconds, image noise is generated and the print quality is deteriorated.
In addition, the Beck smoothness of the coating layer surface means the value measured according to JIS-P8119.

  Further, there is no particular limitation on the method for setting the Beck smoothness of the coating layer surface of the on-demand printing paper within the above range, but for example, it can be carried out by performing a smoothing process with a calendar or the like. The smoothing process using a calendar or the like may be performed within the coating machine process (on-machine), or may be performed outside the coating machine process (off-machine).

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited thereto. In the following examples, “part” represents “part by mass” unless otherwise specified.

Example 1
A base paper for coated paper having a weight of 81.4 g / m ² was used as a base material.
Next, a coating solution having the following composition was prepared.
Precipitated synthetic silica (average particle size: 8 μm) 100 parts Polyvinyl alcohol 10 parts Styrene-butadiene latex 20 parts Calcium stearate (wax) 0.3 parts BXNL (manufactured by Nippon Soda Co., Ltd.) (fluorescent whitening agent) 0.09 Part

Next, double-side coating was performed on the substrate using a blade coater so that the amount of pigment (precipitated synthetic silica) was 8 to 10 g per m ^{2 on the} substrate.
Next, an on-machine type calendar (combination of rubber roll and metal roll, 2 nip) incorporated in the coating machine was subjected to a calendar process and a smoothing process to obtain an on-demand printing paper.

The on-demand printing paper obtained as described above was evaluated according to the following method. The evaluation results are shown in Table 1.
(1) Beck smoothness Measured according to JIS-P8119.

(2) Toner Fixability On-demand printing paper was set on a continuous paper printer (F6768, manufactured by Fujitsu Limited), printing was performed, and toner fixability was evaluated as follows.
(A) Rub the printed part with your finger and observe the degree of toner rubbing with the naked eye.
(B) A transparent or semi-transparent adhesive tape is applied to the printing part, and then the adhesive tape is peeled off, and the degree of peeling is observed with the naked eye.
(C) Toner blocking is evaluated at a portion where the toners contact each other.
The toner fixing property was evaluated according to the following evaluation criteria.
A: No toner adheres to the adhesive tape.
○: Toner slightly adheres to the adhesive tape.
Δ: Toner adheres to the adhesive tape, but there is no problem.
X: A large amount of toner adheres to the adhesive tape.

(3) Continuous paper printer transportability Set the printer on-demand printing paper used in (2), perform printing, jam on-demand printing paper on drum, heat roll, internal friction, paper blocking, etc. The conveyance trouble was observed and evaluated according to the following evaluation criteria.
A: No problem occurs in the printer transportability by the time of printing 10,000 sheets, and no paper dust is generated inside the printer.
○: No problem occurs in the printer transportability by printing 10,000 sheets, but a slight amount of paper dust is generated inside the printer.
Δ: No problem occurs in the printer transportability by printing 10,000 sheets, but paper dust is generated inside the printer.
X: The printer stops at least once before printing 10,000 sheets.

(4) Cut paper printer transportability Set on-demand printing paper in a cut continuous paper printer (Fuji Xerox Co., Ltd., 4660LPS), perform printing, observe the frequency of misfeeds and stack adequacy, and follow the evaluation criteria below. Evaluation was performed.
A: Misfeet does not occur before printing 5,000 sheets.
○: One misfoot occurs before printing 5,000 sheets.
Δ: Misfeet occurs twice before printing 5,000 sheets.
X: Misfeet occurs 3 times or more by the time of printing 5,000 sheets, or the paper misalignment in the stacker is 5 mm.

(5) Fixing roll stain On-demand printing paper is set in a heat roll type printer (IBM4000 info4000), printing is performed, and the fixing heat roll stain and paper stain are observed. Evaluation was performed.
A: There is no dirt.
○: Slightly dirty, but no problem.
Δ: Dirt is generated, but there is no influence on the paper surface.
X: The roll is soiled and transferred to the paper surface.

(6) Print quality (Fuji Xerox Co., Ltd. color printer "Docutech 60") Set on-demand printing paper, perform printing, print surface defects, dirt, print density, print sharpness, color printing Vividness was visually observed and evaluated according to the following evaluation criteria.
A: Very good.
○: Good.
Δ: Normal.
X: It is bad.

(7) Appropriate offset printing Place on-demand printing paper on a Taiyo Machinery Co., Ltd. form rotary press, perform printing, observe the ink ink fillability, blanket stain, and paper dust generation, and follow the evaluation criteria below. Evaluation was performed.
(Double-circle): It is a level of the coated paper for general offset printing.
◯: There is almost no generation of blanket stains and paper dust, and ink depositability is good.
Δ: Blanket remains slightly dirty and paper dust is slightly generated.
X: The blanket is dirty and a lot of paper dust is generated.

Example 2
An on-demand recording sheet was obtained in the same manner as in Example 1 except that gel synthetic silica was used instead of precipitation synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 60 parts of precipitation method synthetic silica and 40 parts of clay were used instead of 100 parts of precipitation method synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 20 parts of precipitation method synthetic silica and 80 parts of clay were used instead of 100 parts of precipitation method synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 80 parts of precipitation method synthetic silica and 20 parts of talc were used instead of 100 parts of precipitation method synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 60 parts of precipitation method synthetic silica, 20 parts of talc and 20 parts of clay were used instead of 100 parts of precipitation method synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
An on-demand recording sheet was obtained in the same manner as in Example 1, except that 15 parts of precipitation method synthetic silica and 85 parts of clay were used instead of 100 parts of precipitation method synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2
An on-demand recording sheet was obtained in the same manner as in Example 1 except that the calendar process was not performed. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 3
An on-demand recording sheet was obtained in the same manner as in Example 4 except that the calendar process was performed using an off-machine calendar (11 nip) and the smoothing process was performed. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 4
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 60 parts of clay and 40 parts of calcium carbonate were used in place of 100 parts of precipitated synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 5
An on-demand recording sheet was obtained in the same manner as in Example 1 except that 30 parts of clay and 70 parts of calcium carbonate were used in place of 100 parts of precipitated synthetic silica. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 6
An on-demand recording sheet was obtained in the same manner as in Comparative Example 4 except that the calendar process was performed using an off-machine calendar (11 nip) and the smoothing process was performed. The obtained on-demand recording paper was evaluated in the same manner as in Example 1. The results are shown in Table 2.

As is apparent from Tables 1 and 2, the on-demand printing paper of the present invention has good toner fixing properties, printer transportability, and printing quality, and is less likely to cause fixing roll stains. Further, the on-demand printing paper of the present invention is good for offset printing.

Claims (5)

On-demand printing paper comprising a coating layer mainly composed of a pigment and a binder on at least one surface of a substrate,
20% by mass or more of the pigment in the coating layer is synthetic silica,
On-demand printing paper having a Beck smoothness of 30 to 1000 seconds on the surface of the coating layer. The on-demand printing paper according to claim 1, wherein the synthetic silica is precipitated synthetic silica. The on-demand printing paper according to claim 2, wherein the silica has an average particle diameter of 3 to 10 μm. The on-demand printing paper according to any one of claims 1 to 3, wherein the content of the pigment in the coating layer is 20 g or less per 1 m ² of the on-demand printing paper. The on-demand printing paper according to any one of claims 1 to 4, wherein the pigment contains talc, and the content of talc is 5 to 80% by mass based on the total mass of the pigment.