JP2002004197A - Paper prevented from curling and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper preventing curling after heat transfer printing with an electrophotographic copier, and to provide a method for producing the paper. SOLUTION: The curling is prevented by suppressing a difference in longitudinal and transverse ratios of the right and back side Young's moduli [(T/Y) difference] which is the difference of the longitudinal and transverse ratio of the right side Young's modulus [(T/Y) right side] from the longitudinal and transverse ratio of the back side Young's modulus [(T/Y) back side] of the paper within 0 to +0.15 in the width direction. Furthermore, the curling is prevented by adjusting a ratio J/W which is the ratio of the pulp suspension speed discharged from a paper machine headbox to the wire speed within the range of 1.000-1.008.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper in which curl after thermal transfer by an electrophotographic copying machine or the like (hereinafter referred to as "paper passing curl") is prevented and a method for producing the same.

[0002]

2. Description of the Related Art As is known in the prior art, attempts to improve the paper passing curl are made by various methods by various companies. In the case of Japanese Patent Application Laid-Open No. Hei 2-217862, although the content focuses on the Young's modulus aspect ratio [(T / Y)] as in the present invention, it is applied to all layers of paper. There is a problem in that the mechanism of the paper passing curl generation caused by the difference in the amount of contraction between the front and back sides has not necessarily been fundamentally elucidated.

Conventionally, most of the papers except for special papers such as nip papers whose orientation is required as a quality characteristic,
It is general that the final product is manufactured at a set value based on the J / W ratio at which the best formation is obtained. The formation is H. of each machine maker. The J / W ratio for obtaining the best formation is usually different for each machine because the J / W ratio differs depending on the combination of the BOX and the former type. 1.02.

[0004] In the prior art, the set value of the J / W ratio places importance on optimizing the formation, and optimizes the Young's modulus aspect ratio difference ((T / Y) difference) on the front and back of the paper. The desired J / W ratio was not set.

[0005] It is known that the dewatering state of the pulp suspension on the wire usually dehydrates faster on the back surface (the surface in contact with the grate net) and becomes slower toward the surface. This deteriorates the yield of fine fibers and the like on the back surface, resulting in low density. Conversely, the yield is improved on the front surface and the density is higher than on the back surface.

[0006] When paper is dried, pulp fibers shrink. It is apparent that this shrinkage is transmitted to the whole paper and is more likely to be adversely affected as a curl factor as the number of bonding points between the fibers is increased, that is, as the number of fine fibers is increased and the density is increased. The occurrence of the density difference between the front and back sides has a significant influence on the curl of the paper, that is, dimensional stability is deteriorated (paper curl is deteriorated).

[0007] The occurrence of curl is one of the causes of a paper passing trouble at the time of copying (paper jam, poor paper discharge accommodating ability), and a complaint at a customer due to poor stacking appearance after copying.
From this, the front and back Young's modulus aspect ratio difference ((T / Y) difference)
It is necessary to manufacture paper with small curl and good dimensional stability by suppressing the width in the width direction.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a prior art J / J which focuses on optimizing formation.
Instead of setting the W ratio, the paper surface Young's modulus aspect ratio [(T /
Y) Back surface Young's modulus aspect ratio [(T / Y) back]
The difference between the front and back Young's modulus aspect ratio [(T / Y) difference]
The J / W ratio is to be set for the purpose of minimizing and optimizing in the width direction.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above, and as a result, have come to invent a paper in which curling is prevented and a method for producing the same according to the present invention.

That is, the curl-prevented paper of the present invention has a difference in the Young's modulus aspect ratio [(T / Y) back] of the back surface Young's modulus aspect ratio [(T / Y) table] (hereinafter referred to as front and back). The difference in the Young's modulus aspect ratio (referred to as (T / Y) difference) is 0 to +0.15 or less in the width direction.

Further, the method for producing a curled paper according to the present invention is characterized in that the ratio of the pulp suspension speed (J) discharged from the paper machine head box to the wire speed (W) (hereinafter referred to as J).
/ W ratio) is adjusted in the range of 1.00 to 1.008.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Paper surface Young's modulus aspect ratio [(T /
Y) Back surface Young's modulus aspect ratio [(T / Y) back]
The curl is prevented by suppressing the front-back Young's modulus aspect ratio difference ((T / Y) difference) within 0 to +0.15 in the width direction.

Here, the front and back Young's modulus aspect ratio difference [(T
/ Y) difference] is within the range of 0 to +0.15, which is obtained from the curl result of actually passing and copying the sample. As shown in FIG. 4, it can be seen that by setting the front / back Young's modulus aspect ratio difference ((T / Y) difference) within 0 to +0.15, the paper copy curl is reduced and the curl is prevented.

Further, the J / W ratio should be 1.000 or more.
By adjusting the ratio to 008 or less, the front-back Young's modulus aspect ratio difference ((T / Y) difference) can be kept within 0 to +0.15.

The method of implementing the present invention firstly uses the current J / W
Surface Young's modulus aspect ratio [(T / Y) table] and back Young's modulus aspect ratio [(T / Y)]
Back) is measured. Further, using these results, the front / back Young's modulus aspect ratio difference ((T / Y) difference) is calculated.

In the measurement of the aspect ratio of the front surface and the back surface in the present invention, the tape peeling method was used to measure the aspect ratio of the sample peeled on the front surface and the back surface using SST-3000 (manufactured by Nomura Corporation). The surface Young's modulus aspect ratio of the paper sample is [(T / Y) table], the back surface Young's modulus aspect ratio is [(T / Y) back], and the front and back Young's modulus aspect ratio difference [(T / Y /
Y) Difference] is represented as the following mathematical formula 1.

[0017]

[(T / Y) difference] = {[(T / Y) table] − [(T / Y) back]} (Equation 1)

In general, paper having a large Young's modulus aspect ratio is poor in dimensional stability, and it is said that the paper becomes more stable as it approaches 1.

It is a well-known fact that fiber contraction occurs when thermal transfer is performed by an electrophotographic copying machine or the like.
If the Young's modulus aspect ratio of the front surface and the back surface is significantly different, it is clear that the degree of fiber shrinkage is different between the front surface and the back surface.

From this, it can be said that a paper having a small Young's modulus aspect ratio difference ((T / Y) difference) between the front surface and the back surface, that is, the more stable the fiber shrinkage balance between the front and back surfaces, the more excellent the dimensional stability. .

After confirming the level of the front / back Young's modulus aspect ratio [(T / Y) difference] in the current width direction, the J / W ratio is sequentially changed from the current level, and the front / back Young's modulus aspect ratio is determined in the same manner. The difference [(T / Y) difference] is obtained. Among the J / W ratios at each level, the J / W ratio in which the Young's modulus aspect ratio difference ((T / Y) difference) between the front and back is within the range of 0 to +0.15 in the width direction.
The value of the W ratio is a method for producing paper in which curling is prevented.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1, 2 and 3 show an embodiment of the present invention. As comparative examples, J / W ratios of 1.020 and 1.010, which are the prior art, and as examples, J / W ratios of 1.000 and 1.008 of the present invention were obtained at respective J / W ratios. Front and back Young's modulus aspect ratio difference ((T / Y)
Difference] was measured. FIG. 4 shows the result of passing copy curl at each J / W ratio.

Example 1 The J / W ratio is 1.000. The paper sample produced at a J / W ratio of 1.000 was peeled off from the front and back samples using a tape peeling method, and the surface Young's modulus aspect ratio [(T / Y)
Table) and the back surface Young's modulus aspect ratio [(T / Y) back] are SST-
Measure according to 3000. Further, the front / back Young's modulus aspect ratio difference ((T / Y) difference) is calculated using these results.
Obtained [(T / Y) table], [(T / Y) back], [(T
/ Y) difference], and the results of passing copy curl are shown in FIGS. 1, 2, 3 and 4.

Example 2 A paper sample is obtained in exactly the same manner as in Example 1 except that the J / W ratio is set to 1.008. The measurement method and the calculation method are the same as in the first embodiment. The obtained [(T /
Y) Table], [(T / Y) back], [(T / Y) difference], and the results of passing copy curl are shown in FIGS. 1, 2, 3, and 4.

COMPARATIVE EXAMPLE 1 The prior art 1.02 in which the J / W ratio is emphasized for formation
Set to 0. A paper sample is obtained in exactly the same manner as in Examples 1 and 2, except that the J / W ratio is set to 1.020. Example 1 and Example 2 for measurement method and calculation method
Is the same as [(T / Y) table], [(T /
Y) Back], [(T / Y) difference], and the results of passing paper copy curl are shown in FIGS. 1, 2, 3, and 4.

Comparative Example 2 A paper sample was obtained in exactly the same manner as in Example 1, Example 2 and Comparative Example 1 except that the J / W ratio was changed to 1.010. The measurement method and the calculation method are the same as those of the first embodiment, the second embodiment, and the first comparative example. Obtained [(T / Y)
Tables, [(T / Y) back], [(T / Y) difference], and the results of passing copy curl are shown in FIGS. 1, 2, 3, and 4. FIG.

Surface Young's modulus aspect ratio [(T / Y) table], back Young's modulus aspect ratio [(T / Y) back], front and back Young of paper samples of Examples 1 and 2 and Comparative Examples 1 and 2 above. When the aspect ratio difference ((T / Y) difference) and the pass-through copy curl result are viewed in FIGS. 1, 2, 3, and 4, Examples 1 and 2 of the present invention are compared with Comparative Examples 1 and 2. As the J / W ratio decreases, the front-back Young's modulus aspect ratio difference ((T / Y) difference) decreases,
It is within 0 to +0.15, and it can be seen that the contraction balance on the front and back is balanced. However, J / W ratio 1.01
Even at 0, it is within the range of 0 to -0.15, but the level of paper passing curl is large, and the J / W ratio is
It can be seen from the result of the passing copy curl that the occurrence of the passing paper curl is suppressed by being within the range of 1.008.

[0029]

As described above, according to the manufacturing method of the present invention, instead of the conventional J / W ratio emphasizing formation, J / W ratio is reduced.
By adjusting the / W ratio to 1.00 to 1.008, the front-back Young's modulus difference ((T / Y) difference)
+0.15 can be accommodated, and an excellent effect of suppressing the occurrence of paper passing curl can be obtained.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, in which the J / W ratio is 1.
It is a width direction measurement result of surface Young's modulus aspect ratio [(T / Y) table] at 020, 1.010, 1.008, and 1.000.

FIG. 2 is a measurement result in the width direction of the back surface Young's modulus aspect ratio [(T / Y) back surface].

FIG. 3 is a width direction measurement result of a front / back Young's modulus aspect ratio difference ((T / Y) difference).

FIG. 4 shows a result of passing copy curl at each J / W ratio.

[Explanation of symbols]

 [(T / Y) Table]: Front Young's modulus aspect ratio [(T / Y) Back]: Back Young modulus aspect ratio [(T / Y) difference]: Front and back Young modulus aspect ratio difference

Claims (2)

[Claims] 1. The surface Young's modulus aspect ratio of paper [(T / Y)
The difference in the aspect ratio [(T / Y) back] of the back surface relative to the front surface (hereinafter referred to as the front-back Young's modulus aspect ratio difference [(T / Y) difference]) is 0 to +0.15 in the width direction. Characterized paper that has curl prevention. 2. The method for producing a curled paper according to claim 1, wherein a ratio of a pulp suspension speed (J) discharged from a paper machine head box to a wire speed (W) (hereinafter J / W) is used. 1.00 to 1.008
A method for producing paper with curling prevented, characterized in that it is adjusted to a range of: