JP3210777B2 - Transparent transfer paper for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent transfer paper for use in electrophotographic copying machines and printers, and more particularly to a transparent transfer paper for electrophotography which has high transparency and has little swell after heating and printing. is there.

[0002]

2. Description of the Related Art For the purpose of obtaining a transparent transfer paper for electrophotography having a natural surface property and a good preservability, a neutral paper is produced from a raw material that has been beaten. When such a raw material is used, it is very difficult to obtain a transparent transfer paper that satisfies both transparency and low unevenness after heating and printing in a copying machine. Various improvements such as reduction have been attempted.

Specific methods include adjusting the fiber length by devising beating conditions, increasing the dewatering property in the wire part and the water squeezing property in the press part by adding a drainage improver, and drying temperature. It has been considered important to adjust the dryer conditions such as the gradient in order to achieve high transparency and to reduce the unevenness of the paper after heating and printing.

[0004]

In order to reduce the unevenness of the paper after heating printing while maintaining the transparency, various methods described above were studied. However, there are limitations to adjusting the degree of beating because transparency and strength are affected,
Addition of the drainage improver does not improve the drainage sufficiently even if the amount is increased, only the fiber is aggregated and the formation deteriorates. Satisfactory results could not be obtained, because it was impossible to do so.

It is an object of the present invention to improve transparency, which is an important quality characteristic of transparent transfer paper for electrophotography, and to reduce unevenness after heating and printing. That is, an object of the present invention is to provide a transparent transfer paper for electrophotography which has less skewing after heating and printing when used in an electrophotographic copying machine or printer.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have tried various analyzes on the mechanism of generation of unevenness after heating and printing in a copying machine. As a result, like a copying machine for drawings in which paper is continuously supplied in a wound state,
Usually, since the sheet is often heated under tension, it has been found that uneven shrinkage occurs in the width direction, which causes unevenness. The non-uniform shrinkage in the width direction was related to the fact that the Poisson's ratio when a load was applied in the papermaking direction was locally different at each position in the direction perpendicular to the papermaking direction.

As a result of further study, it was found that 15
The absolute value of the difference between the two Poisson's ratios measured at positions adjacent to each other at a distance of mm
It has been found that when the paper is adjusted so as to be 0.05 or less, it is possible to obtain a transparent transfer paper for electrophotography which has good transparency and has less unevenness after heating and printing.

The present invention is directed to neutral paper obtained by making cellulose fiber having a Canadian standard freeness of 80 ml or less, wherein the difference in Poisson's ratio measured at two adjacent positions 15 mm apart from each other at right angles to the papermaking direction. The present invention relates to a transparent transfer paper for electrophotography, which has an absolute value of 0.05 or less at any place on the paper surface, has high transparency, and has little unevenness after heating and printing.

The transparent transfer paper for electrophotography in the present invention includes electrophotographic copying machines, page printers, and the like.
It is used as a recording material for continuous printers, plotters and the like to which this method is applied.

The cellulose fibers used in the transparent transfer paper of the present invention include NBKP, LBKP, NBSP and LB.
Examples thereof include wood pulp fibers such as SP and non-wood pulp fibers such as rice straw, straw, bagasse, and kenaf. In use, they may be used alone or as a mixture in proportions depending on the purpose.

The viscosity of a cellulose fiber measured according to TAPPI standard method T230 OS-76 is 10 to 15 cp.
In the case of s, a transparent transfer paper for electrophotography is obtained, in particular, with less unevenness after heating printing. If a cellulose fiber having a viscosity of more than 15 cps is used, it is difficult to obtain high transparency, and if it is less than 10 cps, there is a tendency that the unevenness is deteriorated.

The cellulose fiber in the present invention is beaten by a beater such as a double disc refiner, deluxe finer, Jordan or the like to a Canadian standard freeness of 80 ml or less, and then papermaking. As the paper machine, a fourdrinier paper machine, a circular net paper machine, a twin-wire paper machine, an on-top paper machine, or the like can be used.

The neutral paper of the present invention has a pH of 6.8 to 8.8.
Is a paper made in a neutral to weakly alkaline region, and contains, if necessary, a dye, a filler, a sizing agent, a fixing agent, a dry paper strength enhancer, etc., which are usually used in paper making. It is also possible to apply a binder such as starch or polyvinyl alcohol or a conductive agent such as sodium chloride to the surface of the base paper by a size press or the like.

The Poisson's ratio of the present invention is defined by JIS P 8
During the tensile test of the sample in the papermaking direction performed in accordance with 113,
This is the ratio of the strain in the direction perpendicular to the papermaking direction to the strain in the papermaking direction measured by a laser interference displacement measuring device (Specriser, manufactured by Toyo Seiki Co., Ltd.). Specifically, the strain in the papermaking direction is 1%
The Poisson's ratio was determined from the strain in the direction perpendicular to the papermaking, and measured at the same five positions in the width direction, and the average value was used as the Poisson's ratio at that position.

The absolute value of the difference from the Poisson's ratio at a position 15 mm apart in the width direction obtained in the same manner was used as an index of uniformity. The absolute value of the difference from the Poisson's ratio at a position 15 mm apart in the width direction is 0.05
In the following cases, a transparent transfer paper for electrophotography with less unevenness can be obtained.

Since the Poisson's ratio of the present invention changes depending on the basis weight, orientation, density, stress at the time of drying, etc. of the paper, it is necessary to reduce those local fluctuations to reduce the fluctuation of the Poisson's ratio. Is necessary. As described above, in order to make the characteristics of the paper uniform, it is first attempted to improve the formation and reduce the change in basis weight, but in addition, the orientation, density, stress during drying, etc. are also uniform. It will be necessary to achieve this.

Means for this are (1) adjusting the jet / wire speed ratio on the wire to make the local fiber orientation uniform, and (2) making the moisture distribution of the press felt uniform. It is effective to make the moisture distribution of the wet paper uniform, and (3) to make the temperature and moisture distribution of the paper before the calender uniform. By implementing these alone or in combination of several types, the Poisson's ratio can be made uniform.

[0018]

According to the present invention, the Canadian standard freeness is 80 ml.
Neutral paper obtained by making the following cellulose fiber paper, the absolute value of the difference in Poisson's ratio measured at two adjacent positions 15 mm apart in a direction perpendicular to the papermaking direction, anywhere in the paper surface , 0.05 or less, the electrotransparent transparent transfer paper for electrophotography has high transparency and has little unevenness after heat printing.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. The present invention is not limited to the embodiments. All parts and percentages in the following are by weight. Further, the value indicating the coating amount is the weight after drying unless otherwise specified.

Example 1 0.5 parts of cationic starch (Kate F, manufactured by Oji National Co., Ltd.), alkyl ketene dimer sizing agent (SPK903, Arakawa Chemical Co., Ltd.) were used for 100 parts of NBKP beaten to a Canadian standard freeness of 80 ml with a disc refiner. Was added to make a stock. In addition, the viscosity of this NBKP was 12 cps.

Using this stock, a clear transfer paper for electrophotography having a basis weight of 80 g / m ² was produced by a fourdrinier paper machine. In the papermaking, the jet / wire speed ratio was set to 1.0.
By adjusting to 25, the local fiber orientation was made uniform. After 1.5 g / m ² of oxidized starch was applied by a size press and dried, machine calendering was performed so that Beck smoothness was 30 seconds. This sample is referred to as Sample 1.

Example 2 Samples were obtained in the same manner as in Example 1 except that the press felt moisture was made uniform using a steam box instead of adjusting the jet / wire speed ratio.
This sample is referred to as Sample 2.

Example 3 In Example 1, by humidifying with a steam foil,
All samples were obtained by the same method except that the water distribution before the machine calendar was made uniform. This sample is referred to as Sample 3.

COMPARATIVE EXAMPLE 1 In Example 1, except that the jet / wire speed ratio was 0.975, which did not take into account local fiber orientation uniformity.
All samples were obtained in the same manner. This sample is referred to as Sample 4.

Comparative Example 2 Samples were obtained in the same manner as in Example 1 except that NBKP beaten to 100 ml at Canadian standard freeness was used. This sample is referred to as Sample 5.

Example 4 A sample was obtained in the same manner as in Example 1, except that the viscosity of NBKP was changed to four levels of 9, 10, 15, and 16 cps. These samples are referred to as Samples 6, 7, 8, and 9 in ascending order of viscosity. Table 1 summarizes the above results.

[0027]

[Table 1]

In Table 1, the J / W ratio indicates the jet / wire speed ratio. The Poisson ratio difference is 53
It is a value obtained from the value of each of the test pieces having a width of 15 mm prepared by division. The value of Poisson's ratio is 0.45 to 0.5
It was 5. In addition, the transparency is determined by TAPPI standard method T-44.
This is a value measured according to 2su72. As the transparent transfer paper for electrophotography, the transparency is 70% or more, preferably 72% or more.
% Or more is required.

The squeal is an electrophotographic copying machine (FX508).
(0, manufactured by Fuji Xerox Co., Ltd.). The results were visually evaluated for the roughness of the paper surface immediately after printing, with も の indicating little unevenness, Δ indicating slight unevenness, and × indicating many. The lower limit of the quality is sparse but preferably ○.

From the comparison between Samples 1 to 3 and Table 4 in Table 1, it can be seen that, when the difference in Poisson's ratio is 0.05 or less, a transparent transfer paper for electrophotography with less unevenness can be obtained. From a comparison of Samples 1 and 5, it is clear that beating to 80 ml or less at Canadian standard freeness yields a highly transparent electrophotographic transparent paper.

From Sample 1 and Samples 6 to 9, the viscosity was 1
It is clear that, when the cellulose fiber of 0 to 15 cps is used, a transparent transfer paper for electrophotography having good transparency and less unevenness after heating and printing can be obtained.

[0032]

As described above, the transparent transfer paper for electrophotography of the present invention, that is, a neutral paper obtained by making cellulose fibers having a Canadian standard freeness of 80 ml or less, in a direction perpendicular to the paper making direction. An electrophotographic transparent transfer paper adjusted so that the absolute value of the difference in Poisson's ratio measured at two positions 15 mm apart and adjacent to each other at any location on the paper is 0.05 or less has high transparency, It was clarified that there was little unevenness after printing by heating.

Claims (2)

(57) [Claims] 1. A neutral paper obtained by making a cellulose fiber having a Canadian standard freeness of 80 ml or less, wherein the absolute difference between the Poisson's ratios measured at two adjacent positions 15 mm apart from each other at right angles to the papermaking direction. A transparent transfer paper for electrophotography, wherein the value is 0.05 or less at any place on the paper surface. 2. The cellulose fiber has a viscosity of 10 to 15 c.
2. The transparent transfer paper for electrophotography according to claim 1, wherein the transfer paper is ps.