JP3190503B2 - Recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet having excellent recording suitability as an ink jet recording sheet and also having excellent transportability and transferability required as an electrophotographic transfer sheet.

[0002]

2. Description of the Related Art The characteristics required of ink-jet paper are that the ink does not penetrate too deeply into the paper layer, the print density is high, the adhered ink does not bleed, and the adhered ink follows the fibers on the paper surface. That the feathering that occurs when bleeding occurs does not occur, and that the ink adhering to the paper surface dries quickly and does not stain when touching the printing device.

In order to satisfy these characteristics, conventionally, a coated paper type having a porous ink-absorbing layer on the surface thereof in order to enhance the ink-absorbing performance of ink-jet paper has been used as a base paper of ordinary high-quality paper. Have been.

[0004] However, these coated paper types lack the toner fixability in an electrostatic transfer type (PPC) copier / printer and the transportability in a copier / printer , and are used as so-called electrophotographic transfer paper. The paper was difficult to read.

On the other hand, the characteristics required of the electrophotographic transfer paper are, as described above, good toner transferability, good transportability in a copying machine, and a heat roll for fixing the toner. Pass through, but do not receive thermal curl there, or do not contain substances that cause abrasion of the photoreceptor, avoid mixing foreign matter such as paper dust into the toner, etc. Various proposals have been made to improve these suitability, but on the other hand, when these electrophotographic transfer papers are used in the above-mentioned ink jet recording, they cause problems such as bleeding, feathering, strikethrough, poor fixability, and reduced print density. However, the inkjet recording paper lacked adaptability.

[0006] Recycled paper containing waste paper pulp also has a drawback that feathering cannot be overcome due to bleeding due to the influence of mechanical pulp.

[0007] As described above, if the ink jet printing suitability is to be satisfied, the suitability as the electrophotographic transfer paper cannot be obtained, and conversely, if the suitability as the electrophotographic transfer paper is satisfied, the ink jet print suitability is impaired. Therefore, they could not be converted to each other.

[0008]

SUMMARY OF THE INVENTION The present invention has no ink bleeding and feathering as an ink jet recording paper, has good coloring properties, has excellent ink jet printing suitability, and has good transportability as an electrophotographic transfer paper. An object of the present invention is to provide a recording sheet which is excellent in transferability and has both aptitude as an ink jet recording sheet and electrophotographic transfer sheet.

[0009]

[Means for Solving the Problems] The present invention relates to paper for solving the above problems, and as a result of repeated research and trials,
J. TAPPI paper pulp test method No. 51 (liquid-absorbent paper and paperboard test method - Bristow method) Liquid absorption coefficient Ka with aqueous ink in accordance with the 2900μl / ^{m 2}
· ^{S 1/2} has the following liquid absorption characteristics and a nice
A paper characterized in that the product of the human size degree × oil absorption degree is 3.0 × 10 ³ or less and does not contain calcium carbonate, has properties suitable for ink-jet printing and is required as electrophotographic transfer paper. Has been obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Paper used in the present invention is formed mainly of known wood pulp. They are chemical pulp, bleached bleached kraft pulp, and 100% virgin pulp such as softwood bleached kraft pulp.

[0011] The present invention also enables used paper pulp including mechanical pulp as a raw material.

Conventionally, mechanical pulp (waste paper pulp) has not been good in ink jet printability (especially feathering), but in the present invention, good ink jet print suitability has been obtained even in base paper containing waste paper pulp.

It is desirable that the mixing ratio of the used paper does not exceed 50% by weight, but this mixing amount does not limit the present invention.

The above-mentioned base paper is made from pulp beaten to 300 to 500 ml CSF (Canadian Standard Freeness) within the range for making ordinary high quality paper.

It is usual to add a filler to the base paper. The present invention has focused on this filler.

In ink jet recording, the ink adhered to the paper is held on the paper surface for a very short time, then penetrates into the paper layer, and is fixed together with the evaporation of the solvent. It has been found that the dye in the ink when retained may not develop color as designed.

The present inventors have found that the coloring varies depending on the filler added to the paper. That is, among the commonly used fillers for papermaking, clay, calcium carbonate, talc, titanium dioxide, and synthetic silica, calcium carbonate particularly affects the coloring of black ink, and certain types of black ink have a reddish color. It is to exhibit a tinged color.

This is presumed to be the result of the calcium ions of the calcium carbonate dissolving in water, which is the solvent of the ink, and reacting with the dye component in the ink to form a red color. Therefore, it is desirable that the filler added to the paper does not have calcium ions.

Further, a sizing agent, a paper strength enhancer,
Yield improvers, fixing agents, dyes, and other papermaking auxiliaries are added.

The base paper of the present invention is coated with a coating liquid containing a water-soluble polymer. Water-soluble polymer is starch, casei
Emissions, methylcellulose, carboxymethylcellulose,
Examples are polyvinyl alcohol, polyacrylamide, hydroxyethylcellulose, polyvinylpyrrolidone and the like.

In addition to such a water-soluble polymer, the coating liquid may be a surface sizing agent such as styrene / acrylic copolymer or styrene / maleic anhydride copolymer, a so-called conductive agent such as polymer electrolyte inorganic salts, a lubricant, a defoaming agent. Is added if necessary.

[0022] The coating liquid size press, bill blade coater, a gate roll coater, a rod coater, is coated with an air knife coater, the coating weight is desirably less than many 5 g / ^{m 2} from 0.5 g / ^{m 2} .

Various characteristics of the recording paper thus obtained are measured.

J. TAPPI paper pulp test method No. 5
1 (Test method for liquid absorbency of paper and paperboard-Bristow method)
The relationship between the amount of liquid transferred to the paper and the absorption time was determined by using a dynamic permeability measuring device (manufactured by Toyo Seiki) specified in (1).

The slit width of the head is 1 mm, the load applied to the contact surface with paper is 0.1 MPa , the ink amount is 40 μl,
The composition of the aqueous ink used is as follows.

Naphthol green B 1 part Diethylene glycol 5 parts Ethanol 20 parts Distilled water 74 parts The absorption coefficient Ka is determined from the liquid transfer amount and the absorption time.

The present inventors have determined that the paper thus formed has an absorption coefficient Ka of 2900 μl / m ^2.
It has been found that when the s is smaller than ^{1/2, the} suitability for ink jet printing, particularly the color development and feathering of the ink, are good.

Further, the degree of Sekihito size of the paper (JIS
P8122) and oil absorption (JIS P3001). The degree of Stekigt sizing (size) indicates the time for water to permeate the paper layer, and the degree of oil absorption indicates the time for light oil to permeate the paper layer.

When the product of the sizing degree (seconds) and the oil absorption (seconds) of the paper made as described above, that is, the value of sizing degree × oil absorption degree is smaller than 3.0 × 10 ³ , ink jet printing suitability, especially It was found that feathering and ink fixability were good.

It is considered that the above three factors do not individually have a causal relationship with the suitability for ink-jet printing, and that the three factors complement each other to obtain a synergistic effect.

(Example 1) LBKP 100%, 450 m
To 100 parts of the raw material beaten into 1CSF, 0.05 part of a sizing agent alkenyl succinic anhydride (ASA), 0.5 part of cationic starch and 7 parts of kaolin were internally added, and the basis weight was 64 g / m ^2.
Base paper was obtained. A coating solution of 5% oxidized starch, 0.05% of a surface sizing agent, and 0.1% of a conductive agent is applied to the base paper by a size press, and has an absorption coefficient Ka of 1600 μl / m ² · s ^1/2 and Recording paper was obtained such that the degree of size × the degree of lubrication was 2,800.

Example 2 0.02 parts of sizing agent alkyl ketene dimer (AKD), 0.5 part of cationic starch and 7 parts of kaolin were internally added to the raw material of Example 1 to obtain a basis weight of 64 g.
/ M ² base paper with 5% oxidized starch and 0.02 surface sizing agent
%, A conductive agent of 0.1%, and a lubricant of 0.02% by a size press, and has an absorption coefficient Ka of 1500 μl / m ^2.
A recording paper was obtained in which s ^1/2 and the degree of size × the degree of lubrication were 2,400.

(Example 3) Kaolin and talc were mixed at a ratio of 70:30 as a filler of Example 1, and 7 parts were added.
The same size press processing as in Example 1 was performed, and the absorption coefficient Ka
Was 2900 μl / m ² · s ^1/2 and the degree of size × the degree of lubrication was 1800 to obtain recording paper.

(Example 4) Using LBKP 50% and waste paper pulp 50% as raw materials, the same chemicals and the same amount as in Example 1 were used, the absorption coefficient Ka was 2500 μl / m ² · s ^1/2 , and the size × oiling degree was A recording paper of 2500 was obtained.

[0035] (Comparative Example 1) LBKP100%, raw material 1 which was beaten to 450mlCSF
0.5 part of rosin sizing agent and 2.5 parts of sulfuric acid band in 00 parts
And 7 parts of kaolin, to obtain a base paper having a basis weight of 64 g / m ² . 6% oxidized starch and 0.06 surface sizing agent
%, Conductive agent 0.1% coating liquid with a size press,
A recording paper having an absorption coefficient Ka of 10400 μl / m ² · s ^1/2 and a size degree × oiling degree of 3500 was obtained.

Comparative Example 2 0.03 parts of AKD and 0.1% of cationic starch were used as the raw materials of Comparative Example 1.
5 parts and 7 parts of light calcium carbonate were added internally to obtain 64 g /
base paper to oxidized starch 6% m ^2, a surface sizing agent 0.06%,
A coating liquid containing 0.1% of a conductive agent was applied by a size press to obtain a recording paper having an absorption coefficient Ka of 6100 μl / m ² · s ^1/2 and a size degree × oiling degree of 3900.

Comparative Example 3 100 parts of the raw material of Comparative Example 1
Filler 7 containing 0.05 part of SA, 0.5 part of cationic starch, 70:30 of light calcium carbonate and carion.
6 g of oxidized starch on the obtained base paper of 64 g / m ² ,
A coating liquid of 0.06% of a surface sizing agent and 0.1% of a conductive agent is applied by a size press, and an absorption coefficient Ka is 7800 μl / m.
A recording paper having a size of ² · s ^1/2 and a degree of size × oiling degree of 3300 was obtained.

(Comparative Example 4) The filler of Comparative Example 3 was changed to a heavy carbonate carbonate of 100%, and the absorption coefficient Ka was 4700 μm.
Recording paper was obtained in which 1 / m ² · s ^1/2 and the degree of size × the degree of lubrication were 3000.

Comparative Example 5 0.06 part of ASA, 0.6 part of cationic starch, and 7 parts of light calcium carbonate were internally added to 100 parts of a raw material of 50% LBKP and 50% waste paper pulp to obtain 64 g / m ² . Base paper 5% oxidized starch, surface sizing agent 0.
A coating liquid of 0.6% and a conductive agent of 0.1% is applied by a size press to obtain a recording paper having an absorption coefficient Ka of 5000 μl / m ² · s ^1/2 and a size degree × oiling degree of 3000. Obtained.

(Characteristics and Evaluation of Recording Paper) The characteristics of the recording papers of Examples 1 to 4 and Comparative Examples 1 to 5, and the results of ink jet printing evaluation and PPC copier copy evaluation are shown in Table 1 of the separate sheet.

[0041]

[Table 1] For inkjet printing, an inkjet printer (BJ-10V) manufactured by Canon Inc. was used. In the ink-jet printing evaluation items, the black color development was measured with a black ink and the hue (L *, a * , b *) of the solid black portion was measured with a spectral colorimeter (SZ- # 80 manufactured by Nippon Denshoku Industries Co., Ltd.). Then, ◎ ~ × 5
Evaluate on a scale.

The feathering was visually evaluated on the alphabet printed portion, and evaluated on a scale of ◎ to ×.

The fixability was determined by wiping the solid printed portion with a nonwoven fabric and measuring the time until rubbing did not occur.
Was evaluated in three steps.

The PPC copier is manufactured by Fuji Xerox Co., Ltd.
XEROX-9300 was used.

The transportability was evaluated by cutting the recording paper into A4 size paper, performing 3,000 double-sided copies, and evaluating paper jam, double feeding, folding, wrinkling, sorter properties, etc. on a three-point scale of ◎ to △.

[0046]

According to the present invention, the composition of the base paper is bleached virgin pulp 100.
%, Or the liquid absorption coefficient Ka of the Bristow method using water-based ink on paper containing 50% or less waste paper pulp.
Has a liquid absorption characteristic of 2900 μl / m ² · s ^1/2 or less, and a value of the product of the degree of Stekigt size and the degree of oil absorption is 3.
Paper having a characteristic of 0 × 10 ³ or less and containing no calcium carbonate was produced.

When this paper was printed by an ink jet printer, the paper was excellent in color development of black ink, free of ink bleeding, free of feathering, and excellent in ink jet printability.

When this paper was subjected to a print test using an electrostatic copying machine (PPC), excellent results in transportability and transferability were obtained.

According to the present invention, one type of recording paper can be diverted to ink jet printing paper and electrophotographic transfer paper, which can be provided to the convenience of consumers and is extremely economical.

Further, it is possible to use waste paper pulp-containing paper which has been unsuitable as an ink jet printing paper, thereby achieving cost reduction.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-250091 (JP, A) JP-A-3-65376 (JP, A) JP-A-3-45379 (JP, A) JP-A-1- 135682 (JP, A) JP-A-1-160676 (JP, A) JP-A-6-219038 (JP, A) JP-A-3-27049 (JP, A) JP-A-6-219038 (JP, A) JP-A-5-177921 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00 G03G 7/00

Claims (1)

(57) [Claims] Claims: 1. TAPPI paper pulp test method No. 5
1 (Test method for liquid absorbency of paper and paperboard-Bristow method)
The liquid absorption coefficient Ka of the aqueous ink is 2900 μl /
A recording paper having a liquid absorption property of m ² · s ^1/2 or less, a value of the product of the degree of Steight size × oil absorption of 3.0 × 10 ³ or less, and containing no calcium carbonate.