KR830002287B1 - High yield pulp paper - Google Patents

Abstract

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Description

High yield pulp paper

1 is a graph showing the relationship between the level of transfer paper and curl.

2 is a graph showing the relationship between the water content of the transfer paper and the destruction.

3 is a graph showing the relationship between the initial moisture of the transfer paper and the evaporated moisture during heating and fixing.

The present invention relates to paper used in electrophotographic photocopiers, printers, and line printers of computers.

Conventionally, transfer paper for toner image transfer in electrophotographic needs to satisfy characteristics suitable for an electronic copier, such as the running property of the paper at the time of copying and the fixing property of the radiation quality image. In order to satisfy the conditions, paper commonly referred to as high-quality paper made of 100% chemical pulp has been used.

In order to reduce the cost required for copying, the present inventors have studied the application of heavy paper for copying paper, focusing on paper containing high yield pulp, so-called heavy paper.

However, the high yield pulp referred to here refers to pulp that is produced as a higher cooking yield than conventional chemical pulp, and includes ordinary grand pulp (GP), chemical grand pulp (CGP), refining grand pulp (RGP), Although there are shimmer mechanical pulp (TMP) and semichemical pulp (CP), these heavy papers have been found to have significant drawbacks in radiative aptitude. In other words, the high-yield pulp contains a large amount of hemi cellulose, which has a high hygroscopicity compared to cellulose, so that the moisture content is increased under the same environment as compared to chemical pulp having a low content of hemi cellulose.

Generally, the content of heavy paper products is 6.5 to 8.0%. When this is used for an electrophotographic copier, the amount of evaporation of water from the heated surface during fixing of the toner increases, and the oil difference between the front and back of the paper becomes large. Therefore, the curl is large. In general, paper is less likely to be destroyed when its moisture content increases. Paper curls due to large curls and small breakage, paper discharge tray accumulation defect (automatic kneader), poor paper stacking after copying, bookbinding, and the like can cause problems.

As a means of eliminating this drawback, the method of lowering moisture content is considered. This is to reduce the evaporation water from the heating surface of the paper and the moisture difference between the front and back of the paper when the paper is heated by the toner fixing device of the electrophotographic copying machine. For the relationship between the moisture content and curl, the value measured on the Japanese paper of "Tide Paper" Fider (Basic Weight 66.3 g / m ² ) using an electrophotographic copy machine, Xerox FX 3600, Japan was measured. Fig. 2 also shows the relationship between the moisture content and the destruction by using the same paper using the electronic photocopier FX 3106. Fig. 2 shows the difference between the initial moisture content and the evaporation water through the fixing unit. Figure 3 shows the relationship measured using a Fuji Xerox 3103.

However, since only a small amount of moisture content increases the surface electrical resistance of the paper, it is easy to generate static electricity during the manufacture of the paper or short cuts, and it is easy to remain. Partial scattering of the toner because there is no so-called heavy conveying photoreceptor in which two or more sheets of paper are sent at the same time, that is, the peeling failure of the paper from the photosensitive drum and the photosensitive belt, and the amount of static electricity charged on the paper surface. In other words, there is a poor copy quality due to the explosion of a toner, a large amount of residual discharge static electricity due to the adhesion of the paper discharge tray due to the adhesion between the paper and the electric shock due to contact with the human body during paper discharge.

Conventionally, heavy paper has existing concepts such as high moisture content and easy moisture absorption. In general, no attempt has been made such as adding a hygroscopic conductive agent or lowering the moisture content.

On the other hand, the present inventors have succeeded in maintaining the suitability as an electronic paper for an electrostatic copying machine by maintaining a heavy content moisture at 2.5 to 6.5%, preferably 4.0 to 5.0%, and containing a conductive agent. For example, in the papermaking process, sodium chloride and starch are mixed with ordinary heavy paper, and 0.05 to 0.1 g / m2 coating (only with sodium chloride) is carried out on both sides by surface coating, so that the water content is 2.5. To 6.5%. Containing here means surface coating, internal addition, impregnation, etc.

In the paper of the present invention obtained by the above method, the destruction of the paper is increased by lowering the moisture content, and the curling ability of the paper after fixing is reduced, so that the transfer aptitude of the paper in the electrophotographic copier is improved.

In addition, by lowering the product moisture, the increase in the surface electrical resistance of the paper is suppressed by the inclusion of the conductive agent, and the above-mentioned heavy feeding, poor peeling from the photoconductor, poor copy quality, poor paper discharge tray accumulation, and residual static There is no problem such as electric shock to the human body.

Therefore, the high-yield pulp-containing paper of the present invention is particularly excellent in paper transfer suitability in electrophotographic copiers as compared to conventional heavy paper.

The conducting agent used in the present invention is inorganic salts such as sodium chloride, potassium chloride, lithium chloride, sodium aluminate, sodium phosphate, calcium chloride, magnesium chloride, sodium sulfate, organic acid salts such as potassium phosphate, sodium bromide, soap, phosphate, carbon Surfactants such as acid salts, quaternary ammonium salts, polyacrylates, salts of styrene-maleic acid copolymers, polymer electrolytes such as polystyrene sulfonate and inorganic conductive materials such as silica, alumina and montmorillonite can be enhanced. Anything you can use can be used.

Paper treated with these conductive agents had a surface electrical resistance of 1.0 × 10 ⁹ to 1.0 × 10 ¹¹ Ω in a humidified state (as defined by JIS-P8111) at a temperature of 20 ° C and a relative humidity of 65%. It is preferable to indicate.

Therefore, the type and the amount of the conductive agent can be selected so that the surface electric capacitance of the treated paper is within the above range.

After the paper was pretreated according to 0 JIS-P-8111, the surface electrical resistance was measured in accordance with JIS-C-2318, the moisture content in accordance with JIS-P-8127, and the destruction in accordance with JIS-P-8143.

The paper of the present invention can be used for line printing of printers and computers as applications other than electrophotographic copy paper.

Since the paper of the present invention has lower moisture and less residual static electricity than conventional heavy paper, it is easy to select paper after printing or binding, so that even when used as a continuous slip sheet of a line printer of a computer, the paper transfer or paper selection is improved. Can be used for a wide range of applications.

Furthermore, it is advantageous in terms of the lowest cost when the content of high yield pulp is 2% or more of the total amount of pulp in the paper.

The present invention will be described by the following examples.

Example 1

As in sample 1 of Table 1, 5.0% by weight of starch and calcium chloride 0.3 in papermaking process in heavy paper with a basis weight of 66.38 g / m ² and pulp blending of 20% NBKP, 50% LBKP, and 30% RGP (Reiner Grand Pulp). Surface-coated %% by weight of the liquid coating amount in terms of solid content to 1.2g / m ² starch, potassium chloride 0.07g / m ² , and finally a paper containing 4.5% moisture content was prepared. Table 3 shows the results of testing the physical properties and the runability of the paper.

Example 2

Table 3 shows the results of testing the physical and running characteristics of the paper prepared in such a manner that the moisture content was 3.5% as in Example 1 by the method of time No. 2 in Table 1.

Example 3

Table 3 shows the results of testing the physical and running characteristics of the paper prepared in the same manner as in Example 1 using the method of Sample No. 3 in Table 1 so that the moisture content was 5.5%.

Comparative Example 1

As shown in Sample No. 1 of Table 2, starch 25% by weight during the papermaking process in heavy paper containing pulp with a basis weight of 66.3 g / m ² with NBKP 5%, LBKP 65%, and CGP (Chemical Grand Pulp) 5% The surface coating was carried out, and the paper of 1.2 g / m <^2> was created by converting liquid coating amount into solid content.

Table 3 shows the results of testing the physical and running characteristics of this paper.

Comparative Example 2

Table 3 shows the test results of the physical and running characteristics of the paper prepared in the same manner as in Comparative Example 1 by the method of Sample No. 2 in Table 2.

Comparative Example 3

Table 3 shows the test results of the physical characteristics and the running characteristics of the paper prepared as in Comparative Example 1 by the method of Sample No. 3 in Table 2.

Table-1

Example

TABLE 2

(Comparative Example)

Table 3

1) curl after copy

After copying, the paper is curled upside down and placed on a glass plate to measure the distance between the paper and the glass plate (four corners of paper were measured to record the maximum value.

2) Symbols in the table indicate the following meanings.

○ Good △ Slightly bad × Bad

Claims (1)

Paper containing a high yield pulp containing 2.5 to 6.5 g of water and containing a conductive agent

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