JPH07214892A - Transfer sheet - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a transfer sheet having excellent storability, which can be commonly used as an inkjet recording paper and a transfer paper for electrophotography. [Structure] A size press liquid containing a neutral rosin sizing agent as an internal sizing agent and a surface sizing agent in which an aqueous solution of a polyacrylamide resin having a molecular weight of at least 1,000,000 and an alkaline salt are blended, The transfer sheet is characterized in that the amount of liquid adhered (absolute dryness) is 0.3 g / m ² or more and the smoother smoothness is set to a range of 400 to 600 mmHg by calendering. [Effect] It has excellent ink jet suitability with less bronzing phenomenon in the printed portion, toner fixability, running property, and electrophotographic suitability with good curl, and excellent storage stability.

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 has excellent 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.
Further, the present invention relates to a transfer sheet excellent in storability, which can be commonly used for inkjet recording paper and electrophotographic transfer paper in which a printed portion is less likely to bronze.

[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, a paper having a high water absorbability such as a non-size paper is used based on an acid paper, or an absorbent coating layer such as silica is provided. Things have been proposed (Japanese Patent Publication No. 60-27588 and Japanese Patent Publication No. 63).
-65037).

On the other hand, with the spread of electrophotographic copying machines in society, the role of electrophotographic transfer paper as general office paper or printing paper continues to expand, and it can be used in both ink jet recording systems and electrophotographic copying systems. Development of paper that can be shared is required. A number of patents have already been filed for electrophotographic transfer paper, but currently, alkyl ketene dimer, alkenyl succinic anhydride, etc. are mainly composed of calcium carbonate as an internal filler from the viewpoint of storability and image suitability. Neutral paper containing a so-called neutral sizing agent (Japanese Examined Patent Publication 6)
No. 3-40312 and Japanese Patent Publication No. 2-54543) are becoming mainstream.

However, in actuality, in order to sufficiently express the size property, the current state is to employ a papermaking method in which an aluminum polyvalent metal compound such as a sulfuric acid band is added at a certain ratio, and it is often the case that neutral papermaking is performed. In some cases, it has been used as a measure for preventing roll stains in the papermaking system due to internal sizing agents such as the problematic alkyl ketene dimer and alkenyl succinic anhydride. Although these neutral papers are excellent in storability and whiteness, they have problems such as a decrease in print density and a change in color tone in the inkjet recording method.

[0005]

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 high-quality paper (non-coated paper) used as general office paper and printing paper, there is an increasing demand for a technique for obtaining clear images and printing. Also,
Conventional coated ink-jet paper is not considered for use in other fields.Since it has a coating layer containing silica as the main component on its surface, it may damage the photosensitive drum when used as electrophotographic transfer paper. In addition, there was almost no suitability for electrophotography, such as toner fixability and runnability in a copying machine.

On the other hand, when a neutral electrophotographic transfer paper is used as a plain paper as an ink jet recording paper, the biggest problem with paper of high size is that the dye on the paper is less likely to penetrate into the interior after printing. Therefore, as water and solvent evaporate before they permeate between the fibers of the paper, the dyes associate with each other on the paper, and as the evaporation progresses, dye crystals precipitate on the paper and give a metallic luster. There was a problem that the so-called bronzing phenomenon occurred and the color tone changed significantly. In addition, with paper of low size, the ink sinks deeply into the paper and spreads irregularly on the surface, which causes a drop in print density and the spread of dots and whisker-like blurring called feathering. There was a problem that it occurred. Further, there has been a problem in that the running property, which is an important characteristic of the electrophotographic transfer paper, is deteriorated if these qualities are maintained.

In order to solve the above problems, the present inventors have
A transfer sheet which does not have a conventional aqueous ink receptive coating layer containing a pigment such as silica and which can be commonly used as a high-quality inkjet recording paper and an electrophotographic transfer paper was examined. As a result, the phenomenon of bronzing of the printed portion in the ink jet recording system using the water-based ink containing the direct dye is caused by the use of the neutral rosin sizing agent as the internal sizing agent and the absorption of the size press liquid of a specific amount or more in the size press. If you give a quantity and specify a specific smoothness,
The present inventors have reached the present invention by finding that they can be improved unpredictably by known techniques.

Therefore, it is an object of the present invention to obtain an ink jet recording system having a high density when printing is carried out by an ink jet recording method using a water-based ink containing a direct dye, and an ink jet having less bronzing phenomenon in a printed portion. It is an object of the present invention to provide a transfer sheet excellent in suitability and electrophotographic suitability with good toner fixing property, running property and curl.

[0009]

A transfer sheet that can be used as an inkjet recording paper and an electrophotographic transfer paper of the present invention contains a neutral rosin sizing agent as an internal sizing agent and has at least a molecular weight as a surface sizing agent. A size press solution containing 1 million or more polyacrylamide resin aqueous solution and an alkaline salt is used, the amount of size press solution adhering to the basis weight of the sheet (absolute dryness) is set to 0.3 g / m ² or more, and smoothing is achieved by calendering. The surface smoothness is 400 to 600 mmHg.

The neutral rosin sizing agent used in the present invention is
It is an emulsion type rosin sizing agent which is used in a neutral range of pH 6 to 9 and is emulsified with various surfactants or water-soluble polymers. Here, as the rosin substance, gum rosin, wood rosin, tall oil rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, aldehyde-modified rosin, rosin such as rosin ester, and further the rosins and acrylic acid, maleic anhydride. Acid, fumaric acid, it can be exemplified heating reaction product with α, β-unsaturated carboxylic acid such as itaconic acid, polymerization is performed for the purpose of suppressing elution of rosin substance in the neutral region, insolubilization treatment such as water resistance is performed. be able to. Specifically, the amount of the neutral rosin size added is 0.01 to 2.0% by weight, preferably 0.1% by weight, based on the pulp solids.
1 to 1.0 part by weight is used.

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

Further, for the purpose of expressing the sizing property of the neutral rosin sizing agent, a polyvalent metal compound of Al (for example, a sulfuric acid band, polyaluminum chloride, polyaluminum silicate sulfite, sodium aluminate, etc.) is blended. I don't care.

In the present invention, as a result of intensive studies on a method which meets the above-mentioned object, a bronzing phenomenon of an ink jet recording system using an aqueous ink and a liquid absorption coefficient of a sheet,
It was also found that there is a strong correlation between the running property of the electrophotographic copying machine and the smoothness of the sheet. As a result,
In the present invention, the adhering amount (absolute dryness) of the size press liquid relative to the basis weight of the sheet is regulated to 0.3 g / m ² or more, and the smoother smoothness is regulated to 400 to 600 mmHg to optimize the printability and running property. I found that it can be converted.

By the way, when the amount of adhesion is 0.3 g / m ² or less, in an ink jet recording system using a water-based ink containing a direct dye, sizing tends to be deteriorated, so that bleeding is likely to occur, and feathering is deteriorated along with a decrease in print density, which is desirable. Can not be expected to be effective. Smoother smoothness is 4
If it is less than 00 mmHg, the paper surface is too slippery in electrophotographic aptitude and the paper feeding is deteriorated. On the other hand, 600 mmH
If the value is g or more, the smoothness is poor and the resistance is too large to hinder the paper feeding, and the toner fixing property is deteriorated, which causes a problem that the print failure is likely to occur.

As means for increasing the liquid absorption coefficient of the size press liquid in the size press, in addition to changing the compounding amount of the internally added sizing agent and size press liquid, a method for roughening the pulp freeness of the sheet, and press pressure One or two or more of the following methods are appropriately combined: a method for reducing the water content, a method for reducing the water content of the sheet before the size press, a method for increasing the temperature of the size press solution, and a method for adding a surfactant to the size press solution Can be used.

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

Further, specifically, the smoother smoothness is set to 40.
As a means for adjusting the range of 0 to 600 mmHg, in addition to the above-mentioned means for increasing the liquid absorption coefficient, a method of treating with a roll such as a soft calender, a machine calender and a super calender is used.

In the present invention, as a result of extensive studies on the composition of the size press liquid, in order to obtain the desired result, the size press liquid mainly composed of an aqueous polyacrylamide resin solution having a molecular weight of 1,000,000 or more, preferably about 3,000,000. It has been found that by using the above, it is possible to obtain a product having excellent inkjet suitability and electrophotographic suitability and stable operability. The molecular weight of the conventional polyacrylamide resin is about 350,000, but in the conventional product, when printing is performed by an ink jet recording method using a water-based ink in which a dye is directly blended, spread of dots and whiskers called feathering Bleeding cannot be improved sufficiently. On the other hand, if the molecular weight exceeds 5 million and the viscosity is extremely high, the balance of these properties will be disturbed and, above all, excessive aggregation will occur during use as an additive for papermaking, thus disturbing the texture of the paper. Alternatively, it is not preferable because it causes problems such as staining wires and blankets in the papermaking process.

As a specific method for polymerizing the polyacrylamide resin, it can be produced by a conventionally known polymerization reaction. For example, a predetermined amount of dimethylaminopropyl (meth) acrylamide or a quaternary compound thereof, itaconic acid or a salt thereof and acrylamide as a monomer, and, if necessary, an aqueous solution containing another monomer, isopropyl alcohol, allyl alcohol, A polymerization initiator comprising ammonium persulfate, potassium persulfate, sodium persulfate, or the like and a persulfate salt, or a chain transfer agent such as sodium phosphite or sodium allylsulfonate is appropriately used to adjust the pH to 3 to 6; Of a persulfate and a reducing agent such as sodium bisulfite are added to adjust the monomer concentration to 5
-30% by weight, and the mixture is obtained by heating and stirring at 35 to 95 ° C for 1 to 10 hours. In addition to this, as shown in "Polymer Flocculant" (Eizo Omori), a small amount of redox catalyst is added to a high-concentration aqueous monomer solution to obtain a polymer at a relatively low temperature, or It can be produced by adding a small amount of bisacrylamide and conducting polymerization.

In the present invention, it has been found that the bronzing phenomenon can be further improved by adding an alkaline salt in addition to the above-described technique for the size press liquid. The reason is unknown, but it is considered that the hydroxyl ions in the paper suppress the crystallization of the dye by adding the alkaline salt. It is possible to use strong alkaline substances such as sodium hydroxide and sodium carbonate as the alkaline salt, but one of weak alkaline salts such as sodium tetraborate, potassium tetraborate, sodium silicate, sodium aluminate and sodium hydrogencarbonate. Alternatively, two or more kinds can be appropriately combined.

As a system 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.

In the present invention, it is preferable that the amount of calcium carbonate as a main filler is 12% by weight or less. When the content of calcium carbonate exceeds 12% by weight, it is harder than talc or clay which is a filler used in acidic high-quality paper or electrophotographic transfer paper, so that the photosensitive drum is easily worn and the paper quality is poor. When the amount of filler is increased, the rigidity of the paper is reduced, and the running property and turning property on the machine are deteriorated. As the calcium carbonate, heavy calcium carbonate obtained by crushing limestone, shellfish, chalk, etc., and precipitated calcium carbonate can be used. Further, in the present invention, the particle shape and particle diameter of calcium carbonate are not particularly limited. In addition to calcium carbonate, general inorganic pigments such as talc, kaolin and titanium dioxide may be used together.

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, polyacrylamides, polyethyleneimines, polyamines, polyamide polyamines, urea formalin resins, melamine formalin resins, vegetable gums, polyvinyl alcohol, latex, polyethylene oxide, polyamides. One or more of resins, hydrophilic crosslinked polymer particle dispersions and the like, derivatives or modified products thereof, and compounds such as colloidal silica and bentonite are used in an appropriate combination.

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 agents such as alkyl ketene dimer and alkenyl succinic anhydride. Wide control range of ink permeability. Furthermore, as the liquid absorption coefficient of the size press liquid is increased, the amount of liquid absorbed in the size press process increases, so that the coverage of the pulp fiber and the filler by the size press liquid is improved. In particular, when a high-molecular weight polyacrylamide resin aqueous solution is used, the coatability is remarkably improved, and proper permeation of the ink in the longitudinal direction and diffusion in the lateral direction can be prevented,
As a result, it is presumed that the crystallization of the ink, which is the cause of the bronzing phenomenon, is suppressed without lowering the print density. Further, by defining the smoother smoothness, the running property suitable for electrophotography is improved.

[0028]

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 Calcium carbonate (Okutama Industrial TP-121) 10 parts Neutral rosin sizing agent (NeuSize 770 manufactured by Harima Kasei) 0.7 part Sulfate band 1 part Amphoteric starch (Cato 3210 manufactured by Oji National Co., Ltd.) 1 part Sodium carbonate 0.4 part Yield improver (NR-11LS manufactured by Hymo Co.) 0.02 part Slurry width 1,300 mm, paper speed 1
50 m / min. At 64 g / m ² , base paper was made with a Fourdrinier paper machine. The size press liquid of the following composition on this base paper was 0.6g / m2 when the size press liquid was completely dried.
^It was coated so as to have a thickness of ² and further subjected to a soft calender treatment of 10 kg / cm × 1 nip to obtain an ink jet recording paper having a smoother smoothness of 520 mmHg and a transfer sheet which can be commonly used as an electrophotographic transfer paper. 2. Size press liquid formulation; polyacrylic amide type resin aqueous solution (molecular weight 3,000,000) 1 part Sodium chloride 0.05 part Styrene-acrylic acid type surface sizing agent (Polimaron 1308S manufactured by Arakawa Chemical Co., Ltd.) 0.30 part Sodium hydroxide 0.03 Part water 98.62 parts

The amount of the size press liquid adhered is measured by measuring the sheet before and after performing the size press treatment on the table with one sheet.
It is measured by putting it in a dryer at 10 ° C. for 30 minutes.

Further, the smoothness of the transfer sheet which can be commonly used as the above-mentioned ink jet recording paper and electrophotographic transfer paper is a smoother smoothness meter (SM manufactured by Toei Denshi Kogyo KK, based on J, TAPPI paper pulp test method No. 5). -6A)
Was measured using.

The inkjet suitability was evaluated by cutting a transfer sheet, which can be used as the above-mentioned inkjet recording paper and electrophotographic transfer paper, into A4 size, and at 20 ° C. and 65% R.
After performing humidity control for 24 hours or more in a constant temperature and humidity chamber under the condition of H, BJ- which is a Canon inkjet printer
The following method was performed using 10V. 1. Solid density A solid printing portion printed on two upper and lower parts and three left and right parts of A4 size paper is a Macbeth reflection type densitometer (Macbeth R, R
D-918) was used to measure 12 points, and the average value was used as the solid density. 2. Feathering A4 size paper was printed with a horizontal ruled line pattern and alphabetic characters, and the line thickening was visually evaluated on a five-point scale.
In the table, the judgment of feathering was entered in the order of 5 ... good, 1 ... bad. 3. Bronze 1. Color difference values (L, a, b) of solid areas printed in section
Was measured using a color difference meter (CR-100, manufactured by Minolta Co., Ltd.) and evaluated by the average value of a values.

The electrophotographic suitability of the transfer sheet that can be commonly used as the above-mentioned ink jet recording paper and electrophotographic transfer paper is shown in the following for A4 size vertical samples using an electrophotographic copying machine (SF-9400) manufactured by Sharp Corporation. The method was used for evaluation. 1. Toner Fixing Property A commercially available 18 mm width 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,
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. After curl A4 size paper was passed in the CD direction for single-sided copying, it was placed on a flat table with the curl side facing up, and the highest value among the four corners of the table was measured. 3. Runability 2,500 A4 size paper in the direction perpendicular to the papermaking (CD direction) 2,500
It was evaluated by the number of paper jams and double feeds that occurred when the paper was passed on one side.

Example 2 A sample was prepared in the same manner as in Example 2 except that the amount of the size press liquid deposited was 1.1 g / m ² .

Example 3 A sample was prepared in the same manner as in Example 3 except that the amount of the size press liquid deposited was 0.3 g / m ² .

Example 4 A sample was prepared in the same manner as Example 4 except that the freeness of LBKP was 400 ml and the freeness of NBKP was 450 ml in Example 1.

Example 5 A sample was prepared in the same manner as in Example 5 except that the neutral rosin sizing agent for base paper was changed to 1.0 part in Example 1.

Example 6 A sample was prepared in the same manner as in Example 1 except that the neutral rosin sizing agent in the base paper was changed to 0.1 part.

Example 7 A sample was prepared in the same manner as in Example 7 except that the polyacrylamide-based resin aqueous solution had a molecular weight of 1,000,000.

Example 8 A sample was prepared in the same manner as in Example 8 except that the polyacrylamide resin aqueous solution had a molecular weight of 5,000,000.

Example 9 A sample was prepared in the same manner as in Example 1 except that 0.01 part of sodium hydroxide in the size press solution was added and the amount of water was changed to 98.55 parts.

Example 10 A sample was prepared in the same manner as Example 10 except that the soft calender treatment of 20 kg / cm × 1 nip was carried out in Example 1.

Example 11 A sample was prepared in the same manner as Example 11 except that the soft calender treatment of 5 kg / cm × 1 nip was carried out in Example 1.

Comparative Example 1 A sample was prepared in the same manner as in Example 1 except that the amount of the size press liquid deposited in Example 1 was 0.1 g / m ² .

Comparative Example 2 The amount of the size press liquid deposited in Example 1 was 0.06 g / m ^2.
Comparative Example 2 was prepared in the same manner except that the above was used.

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 changed to 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 molecular weight of the aqueous polyacrylamide resin solution was 350,000 in Example 1.

Comparative Example 5 A sample was prepared in the same manner as in Example 1 except that the aqueous solution of the polyacrylamide resin of the size press liquid was not added, and instead of the oxidized starch (manufactured by Japan Food Processing Co., MS-3800). And Comparative Example 5.

Comparative Example 6 A sample was prepared as Comparative Example 6 in the same manner as in Example 1 except that sodium hydroxide mixed with the size press liquid was not added and the amount of water was 98.65 parts.

Comparative Example 7 A sample was prepared in the same manner as in Example 7 except that the soft calendering treatment of 30 kg / cm × 1 nip was carried out in Example 1.

Comparative Example 8 A sample was prepared in the same manner as in Example 1 except that the soft calendar treatment was not carried out.

The above results are summarized in Tables 1 and 2.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

As is clear from Table 1, according to the present invention, a neutral rosin sizing agent is used as an internal sizing agent, and a size press liquid having a specific amount or more is absorbed by the size press. In addition, by defining a specific smoothness, we manufacture inkjet recording paper with high solid printing density and less bronzing phenomenon, and transfer sheet with excellent storability that can be shared as electrophotographic transfer paper with excellent running performance. It becomes possible to do.

Claims (1)

[Claims] 1. A neutral rosin sizing agent as an internally added sizing agent, and a molecular weight of at least 100 as a surface sizing agent.
Using a size press solution containing more than 10,000 aqueous solution of polyacrylamide resin and alkaline salt, the amount of size press solution adhering to the basis weight of the sheet (absolute dryness) is set to 0.3 g / m ² or more, and a smoother is applied by calendering. A transfer sheet having a smoothness of 400 to 600 mmHg.