JPH11174712A - Paper for printed information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain paper for printed information having suitability to electrophotography, excellent in quality characteristics in bookbinding after discharge through a heat fixing process and so excellent in bookbinding quality as not to cause waving by the influence of the ambient environment after bookbinding. SOLUTION: The paper for printed information is obtd. using wood pulp as principal raw material and has <=0.50% variation in CD elongation when it is allowed to stand in an environment at 25 deg.C and 55% RH for 3O min immediately after a heat fixing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing information sheet used for an on-demand digital printing machine, a copying machine, a printer and the like of an electrophotographic system.
Electrophotographic on-demand digital printers, copiers,
The present invention relates to a printing information sheet having electrophotographic aptitude suitable for a printer or the like and excellent in bookbinding quality.

[0002]

2. Description of the Related Art Office paper, which mainly includes transfer paper for electrophotography, has been widely used in copiers, printers, facsimile machines, etc. with the progress of OA, which is driven by the use of PCs and networks. As the color, the image quality, and the speed have increased, the range of applications has expanded. In addition, recent advances in digital processing technology have expanded the use of electrophotographic digital printers for in-house small-lot printing and short run printing by printing companies.
In the short-run printing market, the need for simple bookbinding of manuals and the like has increased, and the transition from conventional printing to electrophotographic copying machines and printers has been progressing.

However, when a book printed with electrophotographic transfer paper from an electrophotographic copying machine or a printer is bound, a curl or paper break generated in the heat fixing process causes a poor back glue adhesion and a surrounding environment after the binding. This causes undulation (remarkable in a high-humidity environment) due to the influence of, and the quality of bookbinding is impaired. Rippling caused by the influence of the surrounding environment is also a problem in printing, but is particularly a serious problem in an electrophotographic system having a heat fixing step.

[0004] Waving is particularly affected by the surrounding environment after bookbinding. In electrophotographic copiers and printers, since the toner transfer image is fixed by a hot roll or the like, the heating at that time reduces the moisture content of the paper, causing a large difference with the ambient humidity and causing the paper to absorb moisture. Increase the amount. With an increase in the amount of moisture absorption, the elongation of the sheet is large, and particularly, the elongation in the lateral direction of the sheet is remarkable. When lamination is performed by bookbinding, the periphery of the lamination undergoes elongation due to moisture absorption, and the central portion has little moisture absorption and little elongation. Such uneven moisture absorption causes waving, thereby impairing bookbinding quality.

Conventionally, curl after thermal fixing (curl after copying)
Various improvements have been proposed to solve the problem caused by the above. For example, Japanese Patent Publication No. 48-96801,
JP-B-51-102107 and JP-B-54-9
No. 6107 proposes blending inorganic fibers, but with a significant decrease in strength, papermaking problems such as paper-cutting troubles, a decrease in strength such as tear strength and burst strength, and a decrease in bending stiffness. Quality problems. It has also been proposed to incorporate synthetic fibers, but the heat resistance is low and deformation or shrinkage occurs during heat fixing. Furthermore, in any of the methods, since fibers that are more expensive than wood pulp are used, there is a problem that costs are greatly increased.

Further, Japanese Patent Application Laid-Open Nos. Hei 3-287894, Hei 3-287895 and Hei 4-18188
Japanese Patent Laid-Open Publication No. HEI 7-214605 proposes a method for improving the curl of paper containing mechanical pulp by controlling paper characteristics such as equilibrium moisture and the amount of mechanical pulp. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 7-204057 proposes a method of improving curling by blending a large amount of filler. However, when the grammage is increased, stiffness is reduced, and problems such as an increase in the amount of paper dust are generated.

Further, Japanese Patent Application Laid-Open No. Hei 3-236062 discloses a method for controlling the difference between the front and back expansion ratios of paper.
No. 43953 discloses a method for controlling the residual curvature, Japanese Patent Application Laid-Open No. 4-5662 discloses a method for controlling the fiber length of pulp, and Japanese Patent Application Laid-Open Nos. 6-209897 and 8-184983. The publication proposes a curl solving means by controlling the amount of filler and the distribution of ash in the thickness direction.
However, none of these methods was able to sufficiently prevent waving due to the influence of the surrounding environment (for example, high humidity) after bookbinding.

In order to solve the problem of water absorption and waving due to moisture absorption, Japanese Patent Application Laid-Open No. 3-199081 discloses
A method of controlling the underwater elongation ratio of MD (machine direction) / CD (cross direction) of recording paper has been proposed. Japanese Patent Application Laid-Open No. 6-171207 proposes a method in which a coating layer containing a synthetic polymer latex having a specific glass transition point is coated on the back surface of paper. However, any of these methods is to prevent the printing ink portion from waving in the ink jet printing, and it was not possible to sufficiently solve the occurrence of waving due to the influence of the surrounding environment after bookbinding.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, has electrophotographic aptitude, and has quality characteristics at the time of bookbinding of print information paper discharged through a heat fixing step.
No ripples due to the surrounding environment after binding,
An object of the present invention is to provide printing information paper having excellent binding quality.

[0010]

Means for Solving the Problems The present inventor has conducted intensive studies on the quality characteristics at the time of bookbinding of print information paper discharged from the device after the heat fixing step and the bookbinding quality due to the environment after bookbinding. As a result, by adopting the following configuration,
We succeeded in solving the above problems.

(1) In a print information paper mainly made of wood pulp, the CD elongation change rate when left for 30 minutes in an environment of 25 ° C. and 55% RH immediately after the heat fixing step is 0.5.
Print information paper characterized by being 0% or less. (2) The print information sheet as described in (1) above, wherein the basis weight is in a range of 65 to 90 g / m ² and the ash content in the paper is in a range of 15 to 30%. (3) The printing information paper as described in (1) or (2) above, wherein a surface sizing agent containing starch as a main component is applied on both sides of the paper in a range of 1 to 3 g / m ² .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
5 is a graph showing the relationship between the average waving height and the CD elongation change rate when left for 30 minutes in an environment of 5% RH.
As is clear from FIG. 1, the average waving height was found to show a large change at the point where the CD elongation change rate was 0.50%. That is, it can be seen that the average wavy height can be maintained extremely well if the CD elongation change rate is controlled to 0.50% or less.

FIG. 2 shows a case where paper having a basis weight of 75 g / m ² is used.
9 is a graph showing the relationship between the rate of change in CD elongation of paper and ash content (the incineration ignition temperature is set to 575 ° C. ± 25 ° C. according to JISP8128). As is clear from FIG. 2, when the ash content is 15% or more, the CD elongation change rate is 0.50%.
It turns out that it becomes the following.

In the present invention, the CD elongation change rate is defined as a width of 5 in a lateral direction of a sheet (a direction perpendicular to a running direction of the sheet).
A sample having a length of 0 mm and a length of 100 mm was obtained by measuring the tension of about half of the basis weight of the paper on the test paper using an isometric exchange type extensometer. The temperature was kept at 20 ° C. % R
H → 25% RH → 65% RH → 90% RH ”is repeated three times to perform a dehumidification process, and the final 25
% RH → 65% RH, the dimensional change rate is divided by the moisture content change rate of humidity 25% RH → 65% RH, and the dimensional change rate per 1% of moisture (from binding to specific environment) This is a value obtained by integrating the amount of change in moisture when left standing, and represents the amount of change in elongation in that environment).

That is, 2 immediately after the heat fixing step in the present invention.
CD when left in an environment of 5 ° C. and 55% RH for 30 minutes
The elongation change rate is defined as the moisture content of the paper immediately after being discharged through the heat fixing process of an electrophotographic copying machine or a printer and the content when the paper is left in an environment of 25 ° C. and 55% RH for 30 minutes. It means a value obtained by integrating the dimensional change rate per 1% of water with respect to the difference from the water.

The average waving height in the present invention is shown in FIG.
As shown in FIG. 3A, case binding is performed, and the back portion is provided in the MD direction of the paper.
(B) The average waving height (H) was obtained by dividing the sum of the peak heights (h) of the waving on the ground side (all in the CD direction) by the number of waves.

In the present invention, the ash content is 15% to 30%,
Preferably, the range is 15% to 25%. When it is less than 15%, the rate of change in CD elongation exceeds 0.50%, and the waving improvement effect is greatly reduced. On the other hand, if it exceeds 30%, the stiffness of the paper decreases, which causes problems such as poor running properties and poor image quality due to paper dust. Especially the reduction of stiffness is 65 g of grammage
/ M ² is remarkable.

Further, in order to reduce stiffness due to an increase in ash content and to improve poor image quality, the paper surface is subjected to a surface sizing treatment containing starch as a main component in the range of 1.0 to 3.0 g / m ² on both sides. Is preferred. Although the fiber-to-fiber bonding force decreases due to the increase in ash content, it is considered that stiffness can be maintained and paper dust can be suppressed by reinforcing the longitudinal and lateral network structure of the fibers with starch. If the amount of the surface sizing agent containing starch as a main component is less than 1.0 g / m ² , the fiber network structure cannot be sufficiently reinforced. On the other hand, when the coating amount exceeds 3.0 g / m ² , the toner fixing strength is reduced and the document quality is reduced.

Furthermore, the decrease in CD stiffness accompanying an increase in ash content is caused by the ratio of longitudinal wave velocity of ultrasonic pulses to 1.10 to 10.10.
By adjusting to the range of 1.55, the starch reinforcing effect can be more effectively brought out. When the longitudinal wave propagation speed ratio exceeds 1.55, the stiffness of the CD is sharply reduced, which causes a problem in running properties. However, if the longitudinal wave velocity ratio is 1.5
It is considered that when the number is 5 or less, a favorable network structure in the vertical and horizontal directions with respect to the fiber arrangement is formed. In addition, when the ratio is 1.55 or less, the problem of curling when the paper absorbs moisture can be improved. If it is less than 1.10, the orientation of the fibers becomes random, the curl axes become uneven, and the curl shape is not stabilized, which may hinder the storage capacity of the sorting tray. The preferred range of the longitudinal wave velocity ratio is 1.10 to 1.40.

The basis weight in the present invention is from 65 g / m ^{2 to} 90 g / m ^2.
g / m ^2, preferably it is preferably in the range of ^{65g / m 2 ~85g / m 2} . When the grammage is less than 65 g / m ² , the stiffness of the paper is reduced as described above, which hinders the running performance.
On the other hand, if it exceeds 90 g / m ² , the total amount of fibers increases, and the effect of preventing waving decreases.

According to the present invention, the ratio of longitudinal wave propagation velocity of ultrasonic pulse to 1.10 to 10
The adjustment is made to be in the range of 1.55, which is considered to be effective for dispersing the fibers appropriately in the vertical and horizontal directions and preventing the fibers from being arranged only in the MD direction. By adjusting the material ejection speed and wire ratio of the paper machine in a direction to reduce it,
The longitudinal wave velocity ratio can be controlled within this range.

In the present invention, the longitudinal wave velocity ratio (T / Y ratio) of an ultrasonic pulse means a value represented by the following equation. T / Y ratio = (ultrasonic wave propagation speed of MD) / (ultrasonic wave propagation speed of CD) MD: traveling direction of paper machine, CD: perpendicular direction of MD

The starch applied to the paper by the size press of the present invention reinforces a good network structure in the vertical and horizontal directions of the fiber, and greatly contributes to maintaining stiffness and suppressing generation of paper dust. The starch used here is oxidized starch, cationized starch, hydroxyethyl ether starch,
Oxygen-modified starch and the like can be mentioned. Surface sizing agents such as polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, and other resin polymers may be added. This surface sizing agent containing starch as a main component is coated on both sides of the paper with a size press by 1 to 3 g / m ² ,
Preferably, it is applied in the range of 1 to 2.5 g / m ² .

The printed information paper of the present invention may be coated on the surface of the paper by a size press during the paper making process together with an organic salt such as sodium bromate and potassium formate, and a water-soluble adhesive containing starch as a main component. Inorganic salts such as sodium, potassium chloride, sodium sulfate, sodium aluminate, calcium chloride and the like; styrene-maleic acid copolymer salts; polymer electrolytes such as polystyrene sulfonate; alumina;
An inorganic conductive substance such as montmorillonite, a conductive agent such as a surfactant such as soap and phosphate, a pigment, a dye, and the like may be applied.

For the application in the size press step, a conventional size press, a gate roll size press, a size press of a metering blade system, a bill blade, a short dwell coater, or the like can be used. If necessary, a paper strength enhancer such as polyacrylamide, polyamide, polyimide, or polyethyleneimine can also be added internally.

The pulp used in the present invention is a virgin chemical pulp (CP), for example, hardwood bleached kraft pulp, softwood bleached kraft pulp, softwood unbleached kraft pulp, hardwood bleached sulphite pulp, softwood bleached Pulp made by chemically treating wood and other fiber materials such as sulfite pulp, hardwood unbleached sulfite pulp, softwood unbleached sulfite pulp, and virgin mechanical pulp (MP) such as ground pulp
A pulp made by mainly mechanically treating wood and other fiber materials such as chemi-grand pulp, chemi-mechanical pulp, and semi-chemical pulp may be contained.

Further, waste paper pulp obtained by separating unprinted waste paper such as paper cut, waste paper, and narrowed waste paper which are generated in bookbinding, a printing factory, a cutting shop, etc.
For high quality paper, high quality coated paper, medium quality paper, medium quality coated paper, reprinted paper, etc., lithographic printing, letterpress printing, intaglio printing, electrophotographic method, thermal method, thermal transfer method, pressure-sensitive recording method, inkjet A pulp (hereinafter, abbreviated as DIP) obtained by disintegrating a recording method, used paper printed with carbon paper, etc., used water, oil-based ink, used paper written with a pencil, and used newspaper, and disintegrated. ) Can also be used.

Fillers used in the printing information paper of the present invention include calcium carbonate such as heavy calcium carbonate, light calcium carbonate, chalk, etc., silicic acids such as kaolin, calcined clay, porphyrolite, sericite and talc. Examples include inorganic fillers and organic pigments such as urea resins. Calcium carbonate is most suitable for ensuring image quality maintenance in electrophotography.

Examples of the internal sizing agent used for the printing information sheet of the present invention include sizing agents such as rosin sizing agents, synthetic sizing agents, petroleum resin sizing agents, and neutral sizing agents. An appropriate sizing agent such as a sulfate band or a cationized starch may be used in combination with a fixing agent for the fiber.

The printed information paper of the present invention has a surface electric resistivity (JIS-K6911) at a temperature of 20 ° C. and a humidity of 65% RH by using the above-mentioned conductive agent in order to prevent an electrostatic trouble in an electrophotographic system. 1 × 10 ⁹ -1 ×
It must be in the range of 10 ¹² Ω. If the surface electrical resistivity is too high, the amount of electrostatic charge increases, causing image quality defects and poor paper running in a copying machine. If the surface electrical resistivity is too low, the amount of charge decreases, leading to problems such as poor image transfer. Occurs.

Further, in order to improve the sharpness of the copy image portion, the surface unevenness is reduced by a calendering process or the like, and the smoothness (JISP8119) of the print information paper is set to 10 seconds or more, preferably 20 seconds or more. Good to do. In addition, the product moisture immediately after opening is adjusted to 4.0 to 6.5% of the appropriate moisture so as to suppress the occurrence of waving and curling after heat fixing, so that the paper machine drier, the calendering process, and cutting are performed. It is preferable to adjust in a process or the like.

[0032]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto. (Example 1) As shown in Table 1, 100% of hardwood bleached kraft pulp (LBKP) was blended, 15 wt% of heavy calcium carbonate as an ash filler, and 0 alkenyl succinic anhydride (ASA) as an internal sizing agent. 0.1 wt% and 0.2 wt% of cationized starch were blended to make paper so that the longitudinal wave propagation velocity ratio became 1.20.

Further, in order to impart indirect electrophotographic aptitude, 1.0 g of starch was subjected to a two-roll size press treatment.
/ M ^2, polyvinyl alcohol 0.5 g / m ^2, to obtain a printed information sheet of Example 1 was applied so that the sodium chloride 0.1 g / m ^2. The basis weight of this paper is 65 g / m
² , the paper thickness was 93 μm, the smoothness was FS for 22 seconds, the surface electrical resistivity was 7.3 × 10 ⁹ Ω, and the CD stiffness was 31.8 c.
m ^3/100, CD growth rate of change was 0.42%.

The CD elongation change rate of the printing information paper is determined by the publisher system Doch T manufactured by Fuji Xerox Co., Ltd.
Using an Ech Model-135, the amount of water change was measured immediately after and after standing for 30 minutes in an environment of 25 ° C. and 55% RH. It calculated using the dimensional change rate per%.

The evaluation of the average waving height after bookbinding was confirmed by the following procedure. (1) Publisher system Do manufactured by Fuji Xerox
Using a chTech Model-135, 100 double-sided copies were collected using Japanese character manuscripts. (2) 100 bound copy papers were subjected to case binding with a bookbinding machine BO-P6 manufactured by Horizon. The cover is
The BO-P6 cover (with A4S marine window) was used. (3) After the bound paper is left in an environment of 25 ° C. and 55% RH for 30 minutes, the digital paper caliper is used as shown in FIG.
The peak height (h) of the waving of (a) was measured, and the total was divided by the number of waves to obtain an average waving height.

The suitability for copying was confirmed as follows.
Fuji Xerox Publisher System Doch
Using a Tech Model-135, double-sided copying was performed on 10,000 pieces of print information paper in an environment of 25 ° C. and 55% RH, and the number of paper passing failures at that time was measured to evaluate the running performance. Also, the presence or absence of image quality defects at that time was determined. The running performance was evaluated as ○ when the number of occurrences of the paper passing failure was 1 or less, Δ when 2 to 4 times, and × when 5 or more times. Further, regarding the image quality, ○ indicates a favorable level, Δ indicates a level that does not cause a problem in practical use, and X indicates a level that causes a problem.

The results are shown in Table 1. As is clear from Table 1, the printing information paper of Example 1 has a good binding waving of 0.68 mm in average binding height, excellent binding quality, excellent running performance, and good image quality. did it.

(Example 2) As shown in Table 1, 90% of hardwood bleached kraft pulp (LBKP) and 10% of softwood bleached kraft pulp (NBKP) were mixed, and light calcium carbonate as a filler was 17 wt% as ash. 0.1 wt% of alkenyl succinic anhydride (ASA) as an internal sizing agent
% And cationized starch in an amount of 0.2 wt%, and the paper was made so that the longitudinal wave propagation velocity ratio became 1.51.

Further, in order to impart indirect electrophotographic aptitude, the starch is treated with a two-roll size press to make the starch 1.
5 g / m ² , polyvinyl alcohol was applied so as to be 0.5 g / m ² and sodium chloride was 0.15 g / m ² to obtain a print information sheet of Example 2. The basis weight of this paper is 72 g / m ² , the paper thickness is 100 μm, and the smoothness is 3
2 seconds, the surface electrical resistivity 1.1 × 10 ⁹ Ω, CD stiffness is 33.8cm ^3/100, CD elongation rate of change 0.45
%Met.

The bookbinding waving level and copy suitability of this print information sheet were confirmed in the same manner as in Example 1, and the results were shown in Table 1.
It was shown to. As is clear from Table 1, the printing information paper of Example 2 has a good average waving height of 0.78 mm for bookbinding, excellent bookbinding quality, excellent running performance, and good image quality. Was.

Example 3 As shown in Table 1, 100% of hardwood bleached kraft pulp (LBKP) was blended, light calcium carbonate as a filler was 22% by weight as ash, and alkyl ketene dimer (AKD) as an internal sizing agent was used. 0.2wt
% And 0.2 wt% of cationized starch, and the paper was made such that the longitudinal wave propagation velocity ratio was 1.30.

Furthermore, in order to impart indirect electrophotographic aptitude, the starch is processed by a two-roll size press to reduce the starch to 2.
0 g / m ^2, a polyvinyl alcohol 0.5 g / m ^2,
Sodium chloride was applied so as to be 0.1 g / m ² to obtain a print information sheet of Example 3. The basis weight of this paper is 80 g / m ² , the paper thickness is 106 μm, and the smoothness is 4
5 seconds, the surface electrical resistivity 3.7 × ¹⁰ 10 Ω, CD stiffness is 41.7cm ^3/100, CD elongation rate of change 0.47
%Met.

The bookbinding waving level and copy suitability of this print information sheet were confirmed in the same manner as in Example 1. The results are shown in Table 1. As is clear from Table 1, the print information paper of Example 3 has a good average waving height of 0.91 mm for bookbinding, excellent bookbinding quality, excellent running performance, and good image quality. Was.

Example 4 As shown in Table 1, 100% of hardwood bleached kraft pulp (LBKP) was blended, a filler consisting of 70 parts of calcined clay and 30 parts of kaolin clay was used as an ash content of 25% by weight and an internal sizing agent. Rosin 0.2w
The paper was blended with t% and a sulfuric acid band in an amount of 0.2 wt% so that the longitudinal wave propagation velocity ratio became 1.45.

Further, in order to impart indirect electrophotographic aptitude, the mixture was treated with a two-roll size press to make the starch 2.0 g / m ² and the polyvinyl alcohol 0.5 g / m ² .
g / m ^2, by coating sodium chloride so that 0.08 g / m ^2, to obtain a printed information sheet of Example 4. The basis weight of this paper was 75 g / m ² , the paper thickness was 102 μm, the smoothness was 39 seconds by FS, the surface electrical resistivity was 1.3 × 10 ¹¹ Ω,
CD stiffness is 38.0cm ^3/100, CD growth rate of change was 0.43%.

The bookbinding waving level and copy suitability of this print information sheet were confirmed in the same manner as in Example 1, and the results were shown in Table 1.
It was shown to. As is clear from Table 1, the printing information paper of Example 4 had good average waving height of 0.72 mm for bookbinding, excellent bookbinding quality, excellent running performance, and good image quality. .

(Example 5) As shown in Table 1, 80% of hardwood bleached kraft pulp (LBKP) and 30% of used white paper pulp were mixed, and 60 parts of light calcium carbonate as filler and 40 parts of calcined clay were converted to ash. 29 wt%, 0.2 wt% of alkyl ketene dimer (AKD) as internal sizing agent
%, And 0.2 wt% of cationized starch, and papermaking was performed so that the longitudinal wave propagation velocity ratio became 1.40.

Further, in order to impart indirect electrophotographic aptitude, the starch is subjected to a two-roll size press treatment to form 2.
0 g / m ^2, a polyvinyl alcohol 0.8 g / m ^2,
Sodium chloride was applied to a concentration of 0.05 g / m ² to obtain a print information sheet of Example 5. The basis weight of this paper is 9
0 g / m ² , paper thickness 115 μm, smoothness 61 by FS
Sec, the surface electrical resistivity 1.0 × 10 ¹² Ω, CD stiffness is 47.4 cm ^3/100, CD elongation rate of change 0.50%
Met.

The bookbinding waving level and copy suitability of this print information sheet were confirmed in the same manner as in Example 1, and the results were shown in Table 1.
It was shown to. As is clear from Table 1, the printing information paper of Example 5 has a good average waving height of 1.12 mm for bookbinding, excellent bookbinding quality, excellent running performance, and good image quality. Was.

[0050]

[Table 1]

Comparative Example 1 As shown in Table 2, 90% of hardwood bleached kraft pulp (LBKP) and 10% of softwood bleached kraft pulp (NBKP) were mixed, and 5% by weight of heavy calcium carbonate as an ash was used as a filler. Then, 0.2 wt% of an alkyl ketene dimer (AKD) as an internal sizing agent and 0.15 wt% of a cationized starch were blended, and papermaking was performed so that the longitudinal wave propagation velocity ratio became 1.60.

Furthermore, in order to impart indirect electrophotographic aptitude, the starch was treated with 1. roll by a two-roll size press treatment.
0 g / m ^2, was coated sodium chloride so that 0.1 g / m ^2, to obtain a printed information sheet of Comparative Example 1. The basis weight of this paper is 65 g / m ² , the paper thickness is 90 μm, and the smoothness is FS
In 32 seconds, the surface electrical resistivity 9.6 × 10 ⁹ Ω, CD stiffness is 29.2 cm ^3/100, CD elongation rate of change 0.
73%.

With respect to the obtained printing information sheet, the bookbinding waving level and the running property were confirmed by the same experimental method as in Example 1, and the results are shown in Table 2. As is clear from Table 2, the running performance was excellent, but the average waving height of the bookbinding was 2.1.
It was very high at 0 mm, indicating that the binding quality was impaired.

(Comparative Example 2) As shown in Table 2, 100% of hardwood bleached kraft pulp (LBKP) was blended, light calcium carbonate as a filler was 10 wt% as ash, and alkenyl succinic anhydride (ASA) as an internal sizing agent was added. ) 0.1wt
% And 0.15 wt% of cationized starch, and the paper was made so that the longitudinal wave propagation velocity ratio was 1.62.

Further, the starch was coated by a two-roll size press treatment so that the starch became 1.0 g / m ² .
A print information sheet of Comparative Example 2 was obtained. The basis weight of this paper is 75
g / m ² , paper thickness 100 μm, smoothness 47 seconds with FS,
Surface resistivity is 5.9 × 10 ¹² Ω, CD stiffness is 3
7.2cm ^3/100, CD growth conversion rate was 0.61%.

The bookbinding waving level and running property of the obtained printing information paper were confirmed by the same experimental method as in Example 1, and the results are shown in Table 2. As is clear from Table 2, the average waving height of bookbinding is extremely high at 1.90 mm, and electrophotographic equipment has a high surface electrical resistivity, which caused an electrostatic trouble in the paper discharge section.

(Comparative Example 3) As shown in Table 2, 100% of hardwood bleached kraft pulp (LBKP) was blended, 50 parts of calcined clay and 50 parts of kaolin clay were 35 wt% as ash, and rosin as an internal sizing agent was used. And 0.2 wt% of a sulfuric acid band, and the longitudinal wave propagation velocity ratio is 1.
Paper was made to be 65.

Further, in order to impart indirect electrophotographic aptitude, the starch was treated with 1. roll by a two-roll size press treatment.
5 g / m ^2, was coated sodium chloride so that 0.05 g / m ^2, to obtain a printed information sheet of Comparative Example 3. The basis weight of this paper is 90 g / m ² , the paper thickness is 102 μm, the smoothness is 65 seconds by FS, the surface electric resistivity is 1.9 × 10 ¹¹ Ω,
D stiffness is 21.5cm ^3/100, CD elongation change rate was 0.53%.

The bookbinding waving level and the running property of the obtained printing information sheet were confirmed by the same experimental method as in Example 1, and the results are shown in Table 2. As is evident from Table 2, the average waving height of bookbinding was as high as 1.32 mm, and in the electrophotographic equipment, the CD stiffness was low, so that a transport trouble occurred.

[0060]

[Table 2]

[0061]

According to the present invention, by adopting the above-described configuration, the quality characteristics at the time of bookbinding of the print information paper discharged through the heat fixing process and the bookbinding free from waving due to the influence of the surrounding environment after bookbinding. It has become possible to provide a print information sheet having excellent quality and excellent image quality without causing paper feeding trouble.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the average waving height and the rate of change in CD elongation after being left in an environment of 25 ° C. and 55% RH for 30 minutes after bookbinding.

FIG. 2 is a graph showing a relationship between a CD elongation change rate and an ash content of paper having a basis weight of 75 g / m ² .

FIG. 3 is a diagram illustrating a method of calculating an average waving height.
It is a three-dimensional drawing of case binding.

FIG. 4 is a diagram for explaining a method of calculating an average waving height.
It is sectional drawing seen from the ground side.

Claims (3)

[Claims] 1. A printing information sheet mainly made of wood pulp has a CD elongation change rate of 0.50 when left for 30 minutes in an environment of 25 ° C. and 55% RH immediately after the heat fixing step.
% Or less. 2. The printing information sheet according to claim 1, wherein the basis weight of the sheet is in a range of 65 to 90 g / m ² , and the ash content in the sheet is in a range of 15 to 30%. . 3. The printing information sheet according to claim 1, wherein a surface sizing agent containing starch as a main component is applied to both sides of the sheet surface in a range of 1 to 3 g / m ² .