JPH06278358A - Transfer sheet - Google Patents

Abstract

PURPOSE:To provide a transfer sheet which can be used commonly as ink-jet recording paper and transfer paper for electrophotography and is superior in keeping properties. CONSTITUTION:In a transfer sheet, it contains a neutral rosin sizing material as an internal additive sizing material without adding an aluminium multivalent metallic compound (sizing fixing agent), has a ratio(solution-absorbing coefficient) of a quantity of an absorbing solution of a sizing press solution to a sheet basis weight of at least 0.47, a degree of Cobb sizing of 13+ or -2g/m<2> and the size press solution consists preferably mainly of a polyacrylamide resin aqueous solution having a molecular weight of 2,000,000 to 3,300,000 and is compounded with alkali salt. Therefore, the title sheet possesses electrophotgraphic properties wherein bronzing phenomenon of a printing part is little, has favorable ink-jet aptitude. toner fixing properties, running properties and curl and is superior in keeping properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet which is excellent in storability and can be commonly used as an inkjet recording paper of neutral paper having improved ink jet image suitability and a transfer paper for electrophotography. More specifically, even when printing is performed by an inkjet recording method using a water-based ink containing a direct dye, a high-density printed matter can be obtained, and an inkjet recording paper and an electrophotographic transfer having less bronzing phenomenon in a printed portion are obtained. The present invention relates to a transfer sheet that can be shared with paper and has excellent storage stability.

[0002]

2. Description of the Related Art An ink jet recording system using water-based ink has a merit that noise is not generated at the time of recording and a recording image having a high resolution can be mechanically obtained at a high speed by using a highly integrated head. have. On the other hand, when viewed from the side of the paper, in order to obtain a high-quality image, the ink adhered on the recording paper, which is mainly pulp, does not spread irregularly on the surface and is quickly absorbed. is necessary. Therefore, for the purpose of improving the absorbability and drying property of the ink, conventionally, based on acidic paper,
It has been proposed to use paper having high water absorption such as non-sized paper or to provide an absorbent coating layer such as silica (Japanese Patent Publication No. 60-27588 and Japanese Patent Publication No. 63-6).
No. 5037).

On the other hand, with the spread of electrophotographic copying machines in society, the role of electrophotographic transfer paper as general office paper and printing paper has continued to expand, and electrophotography has become possible even in ink jet recording systems using water-based ink. It is required to develop a paper that can be used for copying. A number of patents have already been filed for electrophotographic transfer paper, but currently calcium carbonate is mainly used as an internal filler from the viewpoint of storability and image suitability, and alkyl ketene dimer or alkenyl succinic anhydride is used. That is, neutral papers containing a so-called neutral sizing agent (Japanese Patent Publication No. 63-40312 and Japanese Patent Publication No. 2-54543) are becoming mainstream.

In the present neutral papermaking, calcium carbonate can be used as a filler, which is advantageous in terms of cost, and
It is a well-known fact that there is an advantage that the use of a sulfuric acid band as a size fixing agent can be suppressed. However, in actuality, from the original purpose as a size fixing agent, 0.0
At present, a papermaking method in which an aluminum polyvalent metal compound such as a sulfuric acid band is added at a ratio of about 1 to 0.8% by weight (based on the solid content of pulp) is adopted, which is often a problem in neutral papermaking. In some cases, it is used as a measure for preventing roll stains in the papermaking system due to internally added sizing agents such as alkyl ketene dimer and alkenyl succinic acid.

[Problems to be Solved by the Invention]

However, since the coated ink jet paper as described above has a coating layer containing silica as a main component on the surface, the natural feeling of the paper is impaired and the cost is high.
For general office paper and printing paper, there is an increasing demand for a technique for obtaining clear images and printing on plain paper such as high-quality paper. In addition, the conventional coated inkjet paper has not been considered for use in other fields, and since it has a coating layer containing silica as the main component on the surface, it cannot be used as a transfer paper for electrophotography when it is used as a photosensitive drum. Not only was it damaged, but there was almost no suitability for electrophotography, such as toner fixability and runnability in a copying machine.

On the contrary, when the electrophotographic transfer paper which is a neutral paper as a plain paper is used as an ink jet recording paper using a water-based ink in which a dye is directly mixed in order to improve light resistance and water resistance, the size property is improved. The highest problem with high-quality paper is that after printing, the dye on the paper penetrates between the fibers of the paper, the dyes associate with each other on the paper, and as the water in the ink evaporates, dye crystals form on the paper. A so-called bronzing phenomenon, in which the metal deposits to give off a metallic luster, occurs, and the color tone may change greatly as the print density decreases. In addition, on paper of low size, the ink sinks heavily into the paper and spreads irregularly on the surface of the paper, resulting in a drop in print density and the spread of dots and whisker-like blurring called feathering. There is a problem that it will occur.

In order to solve the above problems, the present inventors have
A transfer sheet which does not have a water-based ink receptive coating layer containing a pigment such as silica and which can be commonly used as a so-called plain ink jet recording paper such as high-quality paper and electrophotographic transfer paper was examined. As a result, the phenomenon of bronzing of the printed portion in the ink jet recording method using the water-based ink containing the direct dye is caused by the use of the neutral rosin sizing agent as the internally added sizing agent and the absorption of the size press liquid of a specific amount or more by the size press The present inventors have found that, when a certain amount of the Cobb size is specified and the degree of Cobb size is specified, it is possible to make an unpredictable improvement by a known technique, and the present invention has been completed.

Accordingly, an object of the present invention is to provide an ink jet recording method which uses a water-based ink containing a direct dye to produce a high-density printed matter and has less bronzing in the printed portion. It is an object of the present invention to provide a transfer sheet having excellent suitability, toner fixing property, running property, and good curl, which is suitable for electrophotography and has excellent storage stability.

[Means for Solving the Problems]

The transfer sheet which can be used as the ink jet recording paper and the electrophotographic transfer paper of the present invention contains a neutral rosin sizing agent as an internal sizing agent, and has a liquid absorption amount of the size press liquid relative to the basis weight of the sheet. Ratio (liquid absorption coefficient) of 0.47 or more and Cobb size degree of 13 ± 2 g / m ²
Is characterized in that.

The neutral rosin sizing agent used in the present invention is
It is an emulsion type rosin sizing agent obtained by emulsifying with various surfactants or water-soluble polymers used in the neutral range of pH 6-9. Here, as the rosin substance,
Roms such as gum rosin, wood rosin, tall oil rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, aldehyde-modified rosin, and rosin ester, and further rosins and acrylic acid, maleic anhydride, fumaric acid, itaconic acid, etc. Examples of the heated reaction product with α, β-unsaturated carboxylic acid include, but insolubilization treatment such as polymerization and water resistance can be performed for the purpose of suppressing elution of the rosin substance in the neutral region.

The ionicity of the neutral rosin sizing agent can be selected from anionicity and cationicity depending on various surfactants or water-soluble polymers used during emulsification, but in the present invention, ionicity does not matter.

Generally, a polyvalent metal compound of Al (for example, a sulfuric acid band, polyaluminum chloride, polyaluminum silicate sulfate, sodium aluminate, etc.) is blended for the purpose of expressing the size of the neutral rosin sizing agent. However, these compounds are not used in the present invention for the purpose of preserving the paper and suppressing the phenomenon of bronzing in the printed portion.

In the present invention, as a result of intensive studies on a method which meets the above-mentioned purpose, the printability and the paper size of the ink jet recording method using the water-based ink, the bronzing phenomenon and the liquid absorption coefficient of the sheet are also examined. It was confirmed that there was a strong correlation. As a result, the present invention has found that the printability can be optimized by defining the liquid absorption coefficient to 0.47 or more and the Cobb size degree to 13 ± 2 g / m ² .

By the way, when the liquid absorption coefficient is 0.47 or less, in the ink jet recording method using an aqueous ink containing a direct dye, the phenomenon of bronzing in the printed portion becomes remarkable, and the desired effect cannot be expected. Also, the degree of Cobb size is 15
When g / m ² or more, when printing is performed by an ink jet recording method using a water-based ink, the ink sinks because the ink penetrates too much into the paper,
Not only the print density is lowered, but also dot spreading and whisker-like blurring called feathering occur. Further, when the Cobb size degree is 11 g / m ² or less, there are problems that the drying of the ink is delayed and the bronzing phenomenon of the ink is easily caused.

As means for increasing the liquid absorption coefficient of the size press liquid in the size press, a method of roughening the pulp freeness of the sheet, a method of reducing the press pressure, a method of reducing the water content of the sheet before the size press, and a size Among the methods of increasing the liquid temperature of the press liquid and the method of adding a surfactant to the size press liquid, one kind or a combination of two or more kinds can be used appropriately.

As means for controlling the permeability of the water-based ink by the ink jet recording method, a method of changing the compounding amount of the internally added sizing agent, an acrylic acid type in the size press liquid,
A method of adding a surface sizing agent such as an α-olefin type or styrene-maleic acid type or a method of adding a surfactant to the size press liquid can be used.

In the present invention, the size press liquid composition was also earnestly studied, and as a result, in order to obtain a desired result, the molecular weight was defined in the range of 2,000,000 to 3.3,000,000.
It is preferable to use a size press liquid mainly composed of an aqueous solution of polyacrylamide resin. The molecular weight of conventional polyacrylamide resins is about 350,000. However, when printing is performed by an inkjet recording method that uses a water-based ink containing a direct dye, the conventional product has spread dots and whiskers called feathering. It is not possible to sufficiently improve the bleeding of ink and the bronzing phenomenon of the printed part.

Furthermore, it is preferable to add an alkaline salt to the size press liquid of the present invention for the purpose of improving the bronzing phenomenon. Regarding alkaline salts, it is possible to use strong alkaline substances such as sodium hydroxide and sodium carbonate, but weak alkaline salts such as sodium tetraborate, potassium tetraborate, sodium silicate, sodium aluminate, and sodium hydrogencarbonate are arbitrarily adopted. You can also do it.

As a method for smearing the above size press liquid in the size press process, a conventional size press, a gate roll size press, a film transfer type size press, a rod coater, a bill blade, a short dwell coater or the like is used. However, a conventional size press is preferable from the viewpoint of the liquid absorption coefficient. Further, at the same time, starch, binders such as polyvinyl alcohol, various surface sizing agents such as maleic anhydride type, α-olefin type, styrene-acrylic acid type, dimensional stabilizers such as ethylene-urea resin, sodium chloride, Of course, it is possible to smear an inorganic conductive agent such as potassium chloride, an organic conductive agent, a surfactant, a pigment or a dye.

The pulp used in the present invention includes NBKP, LBKP, NBSP, LBSP, GP,
In addition to TMP and the like, waste paper pulp can be mentioned. In use, several kinds of them are mixed and used at a ratio according to the purpose. The mixing ratio of the waste paper pulp in the total pulp is preferably 40% or less in order to prevent double feeding in the feeder section of the electrophotographic copying machine and curl after transfer.

The raw materials for the waste paper pulp referred to in the present invention include white, ruled white, cream white, curd, and white, as shown in the waste paper standard quality standard table of the Waste Paper Recycling Promotion Center.
Special white, medium white, imitation, fair white, Kent, white art, special cut,
Examples include separate papers, newspapers and magazines. Further specific examples include non-coated computer paper which is information related paper, printer paper such as thermal paper and pressure sensitive paper, and OA waste paper such as PPC paper, art paper, coated paper, lightly coated paper and matte paper. Coated paper or fine paper, fine color, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, waste paper,
Waste paper such as super-wrapping paper, imitation paper, pure white roll paper, uncoated paper such as milk carton and paperboard, chemical pulp paper,
High-yield pulp-containing paper is used, but printing, copying,
It is not particularly limited whether it is printed or not.

Further, the used paper pulp is generally (1) disaggregated: the used paper is processed by a pulper with mechanical force and chemicals to be disintegrated into fibers, and the printing ink is separated from the fibers. (2) Dust removal: Remove foreign substances (plastic etc.) and dust contained in used paper with a screen, cleaner, etc. (3) Deinking: The printing ink separated from the fiber with a surfactant is removed to the outside of the system by a flotation method or a cleaning method. (4) Bleaching: Improves the whiteness of the fiber by using the oxidizing action and the reducing action. It is made from a combination of 4 steps.

Fillers may be added to the stock obtained by the method of the present invention. Inorganic pigments such as calcium carbonate, talc, kaolin, and titanium dioxide are generally used as the type of filler.However, when printing is performed by an inkjet recording method, bronzing is prevented, and the spread of dots and feathering may occur. It is preferable to use calcium carbonate from the viewpoint of preventing the occurrence of so-called whisker-like bleeding, and from the viewpoint of prevention of drum stains and storage stability when used as a transfer paper for electrophotography.

In addition to the above, various anionic, nonionic, cationic or amphoteric retention improvers and drainage improvers which have been conventionally used within the range of the stock do not impair the desired effects of the present invention. In addition, an internal additive for papermaking such as a paper strength improver or an internal sizing agent is appropriately selected and used as necessary.
For example, polyvalent metal compounds such as Fe, Sn and Zn, and various starches, polyacrylamide, polyethyleneimine, polyamine, polyamide polyamine, urea formalin resin, melamine formalin resin, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, polyamide Resin, hydrophilic crosslinked polymer particle dispersion, etc. and their derivatives or modified materials, colloidal silica, etc.
One kind or two or more kinds of compounds such as bentonite are appropriately combined and used.

It is also possible to appropriately add an internal additive for papermaking such as a dye, a pH adjusting agent, a defoaming agent, a pitch control agent and a slime control agent depending on the purpose.

In the papermaking method of the present invention, a neutral papermaking machine having a papermaking pH of about 6.5 to 9.0 is preferable, but the papermaking machine is a Fourdrinier paper machine, a twin wire paper machine, a combination paper machine, a round net machine. A paper machine, a Yankee paper machine, etc. can be used as appropriate.

[0027]

As defined in the present invention, the neutral rosin sizing agent is an aqueous solution containing a direct dye as compared with the conventionally used neutral sizing agent, alkyl ketene dimer, and alkenyl succinic anhydride. Wide control range of ink permeability. In addition, if a combination of increasing the absorption coefficient of the size press liquid for a sheet with a specified Cobb size degree is combined with the increase in the amount of liquid absorption in the size press process, the coverage of pulp fibers and fillers by the size press liquid will increase. Is improved. In particular, when a high molecular weight polyacrylamide resin aqueous solution is used, the coating property is remarkably improved,
Since it is possible to prevent the appropriate permeation of the ink in the vertical direction and the diffusion in the horizontal direction, it is presumed that crystallization of the ink, which is a cause of the bronzing phenomenon, is suppressed without lowering the print density as a result.

On the other hand, in the sheet according to the present invention, since the aluminum polyvalent metal compound such as the sulfuric acid band is not used as the size fixing agent, the deterioration due to the sulfuric acid group in the paper is prevented.

[0029]

EXAMPLES The present invention will be described in detail below with reference to examples. The present invention is not limited to this. All parts and% in the following are by weight.

Example 1 1. Base paper formulation: LBKP (freeness 350 ml, csf) 70 parts NBKP (freeness 400 ml, csf) 30 parts Light calcium carbonate (Okutama Kogyo TP-121) 10 parts Neutral rosin Sizing agent (NeuSize 770, manufactured by Harima Kasei) 0.7 part Amphoteric starch (Cato 3210, manufactured by Oji National Co., Ltd.) 1 part Yield improver (NR-11LS, manufactured by Hymo Co., Ltd.) 0.02 part Paper making width 1,300 mm, using the slurry of the above composition, Papermaking speed 1
50 m / min. At 64 g / m ² , base paper was made with a Fourdrinier paper machine. This base paper was size-pressed once on the table with the following composition to give a liquid absorption coefficient of 0.5.
A transfer sheet that can be used as the inkjet recording paper of No. 5 and the transfer paper for electrophotography was obtained. 2. Size press liquid formulation: Polyacrylicamide resin aqueous solution (Harima Kasei, G-3000 molecular weight 3 million) 1 part Sodium chloride 0.05 part Styrene-acrylic acid surface sizing agent (Arakawa Chemical Co., Ltd., Polymaron 1308S) 0.30 Part sodium hydroxide 0.03 part water 98.62 parts

The liquid absorption coefficient (K) was measured by the following formula by measuring the sheet weight before and after the size press treatment when performing the size press treatment on the table. K = (W2-W1) / W1 where W1: weight of transfer sheet base paper before size press treatment (g) W2: weight of transfer sheet immediately after size press treatment (g)

As a general characteristic of the transfer sheet that can be commonly used as the above-mentioned ink jet recording paper and electrophotographic transfer paper, the Cobb size degree was in accordance with JIS P-8140, but the contact time with water was 10 seconds.

The inkjet suitability was evaluated by cutting a transfer sheet that can be used as the above-mentioned inkjet recording paper and electrophotographic transfer paper to A4 size, and at 20 ° C. and 65% RH.
After performing humidity control for 24 hours or more in a constant temperature and humidity chamber under the conditions described above, Canon inkjet printer BJ-
The following method was performed using 10V. 1. Solid Density: A solid printing portion printed on two upper and lower parts of an A4 size paper and three parts on the right and left sides is a Macbeth reflection type densitometer (Macb
RD-918, manufactured by Eth Co., Ltd. was used to measure 12 points, and the average value was used as the solid density. Ink jet recording paper is required to have an optical density of 1.25 or higher. 2. Feathering: Horizontal ruled line patterns and alphabet letters are printed on A4 size paper, and the line thickness is visually checked to be 5
The grade was evaluated. 4 for inkjet recording paper
More feathering is needed. 3. Bronze: 1. The color difference value (L, a, b) of the solid portion printed in the section of 1. is a color difference meter (CR-1 manufactured by Minolta Co., Ltd.).
00) was used for evaluation, and the average value of a values was evaluated. Ink jet recording paper is required to have a color difference a value of 2 or less.

The electrophotographic suitability of the transfer sheet which can be commonly used as the above-mentioned ink jet recording sheet and electrophotographic transfer sheet is shown in the following by using an electrophotographic copying machine (SF-9400) manufactured by Sharp Corp. in the A4 size vertical sample. The method was used for evaluation. 1. Toner fixability: Commercially available 18 mm wide cellophane adhesive tape (cellophane tape manufactured by Nichiban Co., Ltd.) was attached to the image portion having an optical density of about 1.4, which was copied by the above copying machine, at a linear pressure of 300 g / cm, and 1 cm / sec. The ratio (hereinafter abbreviated as OD ratio) of the image density after peeling to the image density before peeling when peeling at the speed of was evaluated as an index. OD ratio = image density after peeling / image density before peeling The transfer paper for electrophotography is required to have toner fixability of 0.7 or more in terms of OD ratio. The image density is measured by a Macbeth reflection densitometer (Macbeth RD-
918) was used. 2. Double feed: When 2,500 sheets of A4 size paper were passed on one side in the direction perpendicular to the paper making (CD direction), the number of double feeds generated was evaluated. Seven or less sheets of electrophotographic transfer paper are required. 3. Curl: After passing A4 size paper in the CD direction to make a single-sided copy, place it on a flat table with the curl side facing up and measure the highest value of the four corners above the surface of the table. The average value of the sheets was evaluated. The electrophotographic transfer paper is preferably 3 mm or less.

The storability evaluation of the above-mentioned transfer sheet which can be commonly used as the ink jet recording sheet and the electrophotographic transfer sheet is as follows. 1. A4 after treating with a hot air dryer at 105 ° C for 4 hours
Carry out equal size folding 7 times to make 15 x 7 folds. 2. The appearance when the paper piece is returned to the original size of A4 and habituated by hand is visually judged. An example of the evaluation inferior in storage stability is a state of tearing and breaking from a fold line. Evaluation level 4 or higher is desired.

Example 2 A sample was prepared in the same manner as Example 2 except that the size press treatment was repeated 3 times in Example 1.

Example 3 A sample was prepared in the same manner as Example 3 except that the freeness of LBKP was 400 ml and the freeness of NBKP was 450 ml in Example 1.

Example 4 A sample was prepared in the same manner as Example 4 except that 0.04 parts of sodium hydroxide and 98.61 parts of water in the size press solution were used in Example 1.

Example 5 A sample was prepared in the same manner as Example 5 except that the neutral rosin sizing agent for base paper was changed to 0.8 part in Example 1.

Example 6 In Example 1, the light calcium carbonate of the base paper was not added, and instead, Indonesia clay (BRU manufactured by PTALTER ABADI was used.
-30) was added in an amount of 10 parts and sodium carbonate was added in an amount of 0.4 parts to prepare a sample in the same manner as Example 6.

Example 7 In Example 6, 40 parts of LBKP and NBK were used as the pulp composition of the base paper.
A sample was prepared in the same manner as in Example 7 except that P20 parts and imitation waste paper pulp 40 parts were used.

Example 8 A sample was prepared in the same manner as in Example 1 except that sodium hydroxide in the size press solution was not added and the amount of water was changed to 98.65 parts.

Comparative Example 1 A sample was prepared in the same manner as in Example 8 except that the neutral rosin sizing agent for base paper was changed to 1.0 part in Example 8 and was used as Comparative Example 1.

Comparative Example 2 The neutral rosin sizing agent for base paper in Example 1 was 0.6 parts,
A sample was prepared in the same manner as Comparative Example 2 except that the size press treatment was repeated three times.

Comparative Example 3 A sample was prepared in the same manner as in Example 1, except that the neutral rosin sizing agent for the base paper was not added and the alkyl ketene dimer was replaced by 0.10 part in Example 1 to prepare Comparative Example 3.

Comparative Example 4 A sample was prepared in the same manner as in Example 1, except that the light calcium carbonate of the base paper was not added and 10 parts of talc (Hyogo Clay Co., Hyogo Talc) was used instead. And

Comparative Example 5 In Example 1, 0.85 parts of the neutral rosin sizing agent for the base paper and the polyacrylamide resin aqueous solution of the size press solution were not added, but instead of the oxidized starch (manufactured by Nippon Food Processing Co., MS- Three
A sample was prepared in the same manner as in Comparative Example 5 except that it was changed to 800).

Comparative Example 6 The neutral rosin sizing agent for the base paper in Example 1 was 0.85 parts, and the size press solution was an aqueous solution of polyacrylamide resin having a molecular weight of about 350,000 (Polimaron 500-U, manufactured by Arakawa Chemical Co., Ltd.). A sample was prepared in the same manner except that
And

Comparative Example 7 A sample was prepared in the same manner as in Comparative Example 7 except that 0.5 part of the sulfuric acid band was added to the base paper in Example 1.

Comparative Example 8 A sample was prepared in the same manner as in Example 1 except that 0.1 part of the sulfuric acid band was added to the base paper, and was designated as Comparative Example 8.

The above results are summarized in Table 1. In addition, the judgment of feathering and storability in the table is a 5-step evaluation, and is entered in the order of 5 ... Good, 1 ... Bad.

[0052]

[Table 1]

[0053]

As is apparent from Table 1, the present invention uses a neutral rosin sizing agent as an internal sizing agent without adding an aluminum polyvalent metal compound as a size fixing agent,
Inkjet recording paper with high solid print density and less bronzing phenomenon, and transfer for electrophotography, by allowing the size press to absorb more than a specific amount of size press liquid and by defining a specific degree of Cobb size It is possible to manufacture a transfer sheet that can be shared as paper and has excellent storage stability.

Claims (3)

[Claims] 1. A size press liquid containing a neutral rosin sizing agent as an internally added sizing agent without adding an aluminum polyvalent metal compound as a size fixing agent has a molecular weight of from 2,000,000.
The water absorption ratio of the size press liquid to the sheet basis weight (hereinafter referred to as the liquid absorption coefficient) is 0.47 or more, and the Cobb size degree is 13 ± 2 g / m ² mainly based on 3.3 million polyacrylamide resin aqueous solution. A transfer sheet characterized in that 2. The transfer sheet according to claim 1, wherein the size press liquid is mixed with an alkaline salt. 3. The transfer sheet according to claim 1 or 2, wherein the sheet contains waste paper pulp.