JPH10221876A - Information recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information recording paper excellent in adaptability for double-sided full-color copying, by preparing the paper in such a manner that the water content just after the package of the paper is opened is in a specified range and that the paper shows specified or lower CD elongation and contraction rate and a specified water absorption after the package is opened. SOLUTION: This recording paper has 4.0 to 6.0% water content just after the package of the paper is opened, <=0.45% CD elongation and contraction rate and <=0.6% water absorption in 30sec after the package is opened at 30 deg.C in 85% RH environment. When the water content of the paper just after the package is opened is <=4.0%, the paper has higher electric resistance, which causes troubles in an image. If the water content is >=6.0%, the deformation amt. of the paper after copying on one surface is large, which is apt to produce image defects in the second surface. Therefore, the water content is preferably 4.3 to 5.5%. If the CD elongation and contraction rate increases, deformation of the paper increases, and thereby, the CD elongation and contraction rate is preferably controlled to <=0.45%. To decrease the water absorption at 30 deg.C and 85% RH, a dry pulp and the like is compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording sheet capable of obtaining a high-quality image on both sides when printing on both sides of an electrophotographic copying machine or a printer, and having no image quality defect.

[0002]

2. Description of the Related Art In electrophotographic copying machines, printers, and facsimiles, a charge image is formed on the surface of a photosensitive member or a photosensitive belt such as amorphous silicon or an organic semiconductor, and toner particles are attached to the charge image to form a visualized image. Forming, then, the recording paper is brought into contact with the photosensitive surface and subjected to corona discharge treatment or the like from the back side of the paper to transfer the visualized image to the recording paper, and further fixed on the recording paper by heat, pressure, etc. to print the image. Form.

However, since a color copying machine or printer uses four color toners, its transfer mechanism and fixing mechanism are significantly different from those of a conventional black-and-white copying machine. A transfer mechanism of a color copying machine supports a transfer material such as recording paper on a transfer material holding member such as a transfer drum that rotates in synchronization with a toner image carrier such as a photosensitive drum, and transfers a toner image. An endless belt-shaped transfer material holding member is used instead of the transfer drum system or the transfer drum, and a plurality of image forming means corresponding to each color are arranged along the moving direction of the transfer material holding member. A tandem system or the like is used in which toner of each color formed by each image forming unit is sequentially transferred to a transfer material held thereon to form a color image.

In a conventional black-and-white copying machine, a document used for copying is mainly a character document, but in a color copying machine, a copy of a document having an image on the entire surface, such as a photo document, is increasing. For this reason, the conventional heating and pressure fixing of a black-and-white copying machine mainly employs an upper heating method for heating from a toner fixing surface, but a color copying machine applies a sufficient amount of heat to fix four color toners. Therefore, the upper and lower heating method of heating from the toner fixing surface and the back surface is used,
In addition, the nip forming means and the like are different.

As described above, in the color copying machine, in addition to its mechanism, the characteristics required for the recording paper are greatly different from the monochrome copying machine, such as the type of the original used for copying. For this reason, various problems such as running property, high image quality, and stabilization of curl after copying have newly arisen, and some improvement means have been proposed (for example, Japanese Patent Application Laid-Open No. 1-21-2).
JP-A-92354, JP-A-4-268567, JP-A-4-291351, JP-A-4-337736
JP, JP-A-4-349468, JP-A-5-3
No. 41553, JP-A-5-53363, JP-A-8-1230065, JP-A-8-123066, JP-A-8-171226, and the like.

[0006] Further, color copiers, which include a manual double-sided mechanism using a manual feed tray and an automatic double-sided mechanism for automatically reversing the paper inside the copier, have become more common. Some improvement measures have also been proposed for various problems such as image defects and the like (for example, Japanese Patent Application Laid-Open Nos. Hei 6-186768, Hei 8-171225, Hei 8-171227). .

However, the recording paper proposed for forming a color image or the recording paper conventionally used in a black-and-white electrophotographic copying machine is used in a full-color electrophotographic copying machine. When performing double-sided copying,
It was found that severe defects in image quality occurred under high temperature and high humidity.

[0008] Image defects under high temperature and high humidity during double-sided copying include, when the image density is high such that a full-color image is formed on the entire surface during the first-side copying, the image surface generated by paper waving and thermal expansion and contraction of toner. The curl causes the image on the second surface to be noticeably missing. In order to improve this, means for controlling the ratio between the paper stiffness and the expansion / contraction ratio to a specific value or more has been proposed (JP-A-8-171227). But,
With the increase in the speed of color copiers, when a document with many characters and the like and a low image density is copied at the time of the first-side copying, which was hardly a problem in the past, there is a problem that the image missing on the second side becomes noticeable. Newly revealed.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, to prevent image loss on the second side during double-sided copying in full-color copying machines and printers, and to provide information excellent in suitability for double-sided full-color copying. It is intended to provide recording paper.

[0010]

The present invention has succeeded in solving the above problems by employing the following constitutions. (1) The paper moisture content immediately after opening is 4.0 to 6.0%, and CD
The expansion and contraction rate is 0.45% or less, and 30 ° C. and 85% RH
0.6% water absorption 30 seconds after opening in the environment
An information recording sheet characterized by the following.

(2) With respect to the total pulp weight of the recording paper,
The above-mentioned, comprising 50% or more of dry pulp
(1) Information recording paper described. (3) The information recording paper as described in (1) or (2) above, wherein the basis weight of the recording paper is in a range of 80 to 110 g / m ² .

(4) The fiber orientation ratio of the recording paper is 1.30.
The information recording paper according to any one of the above (1) to (3), characterized in that: (5) An information recording sheet characterized by using the information recording sheet according to any one of (1) to (4) for double-sided printing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS To solve the above-mentioned problems, the present inventors have intensively studied to prevent image loss during double-sided full-color copying, particularly image loss on the second side during double-sided copying under high temperature and high humidity. The lack of image quality caused a copy machine with a high continuous copy speed (sheets / minute) to use a low-image-density original consisting of characters and the like on the first side, and the image was printed on the entire surface on the second side. It was confirmed that the problem occurred remarkably at the trailing edge of the paper when using an original having, and it was particularly likely to occur on several sheets immediately after the start of copying.

The present inventors presumed the cause as follows. In a copying machine with a high continuous copying speed (sheets / minute), the amount of heat held by the fixing device in the early stage of copying is increased so that the toner image can be sufficiently fixed on paper at that speed.
Immediately after copying is started, the amount of heat applied to the sheet is large, and when the image density is low, the heat load on the sheet increases, and the amount of deformation of the sheet increases. If the amount of deformation exceeds a certain value, image omission occurs remarkably at the time of copying the second surface. We have:
The relationship between the temperature change of the fixing device during continuous copying and the rate of occurrence of image loss on the second surface was investigated, and the results shown in FIG. 1 were obtained. It was confirmed that this result coincided well with the change in the amount of deformation of the sheet edge during continuous copying.

The inventors of the present invention have intensively studied means for suppressing the deformation of the sheet after the heating and pressurizing and fixing and preventing the above-mentioned problem of image loss. It was found that the amount of deformation of the sheet edge during continuous copying can be greatly suppressed by setting the CD expansion ratio to not more than 6.0% and the CD expansion / contraction ratio to not more than 0.45%. By using paper satisfying these characteristics, the image loss could be improved in a normal environment, but the image loss in a high humidity environment could not be sufficiently improved.

The present inventors have conducted intensive studies for further improvement. As a result, there is a difference in the deformation of the paper depending on the humidity between the time after the heat fixing on the first surface and the time when the second surface is fixed. It was estimated that when the water absorption after 30 seconds immediately after opening in a 30 ° C. and 85% RH environment was 0.6% or less, image loss could be remarkably improved by combining with the above characteristics.

It has been found that dry pulp is not only effective in reducing the expansion and contraction rate, but also extremely effective in reducing the water absorption rate, and has properties suitable for improving the above properties. 5 dry pulp based on pulp weight
By adding 0% or more, it was possible to successfully obtain the above-mentioned excellent characteristics, and completed the present invention.

Hereinafter, each configuration of the present invention will be described in detail. When the product moisture immediately after opening in the present invention is lower than 4.0%, the electric resistance value becomes high during duplex copying,
Image quality trouble due to discharge occurs. If it is higher than 6.0%, the amount of dehydration of the paper moisture at the time of copying the first side rapidly increases, so that the amount of paper deformation after the copying of the first side becomes extremely large, and the image loss is more likely to occur on the second side. .
Therefore, the proper water content immediately after opening is adjusted to 4.0 to 6.0% by a dryer, a calendering process, a cutting process, and the like of a paper machine. A more preferable range of the appropriate moisture immediately after opening is 4.3 to 5.5%.

The MD used in the present invention means a direction parallel to the traveling direction of the paper machine at the time of paper production, and the CD means a direction perpendicular thereto. In the present invention, the expansion and contraction rate means “humidity 65% RH → 25% RH → 65” at a temperature of 20 ° C.
% RH → 90% RH ”means a dimensional change rate when the moisture absorption / desorption treatment of three cycles of“% RH → 90% RH ”is repeated and 65% RH → 25% RH is changed in the final cycle. The sample used for the measurement of the expansion and contraction ratio was 50 mm in width and 100 mm in length on a paper CD.
mm, and the measurement was carried out using an isometric exchange type extensometer under a tension of about half of the weighed amount.

Since an increase in the CD expansion / contraction ratio increases the amount of paper deformation immediately after copying the first side, it is appropriate in the present invention that the ratio be 0.45% or less. The method of reducing the CD stretch ratio in the present invention can be achieved by blending dry pulp such as LBKP, reducing the proportion of fibers having a shorter fiber length in the fiber length distribution, and reducing the fiber orientation ratio. The fiber orientation ratio is desirably 1.30 or less from the viewpoint of the CD stretch ratio. In addition, a more preferable fiber orientation ratio is 1.00.
１．２1.25.

The water absorption in the present invention refers to the increase in the weight of the paper immediately after opening the package in a 30 ° C., 85% RH environment using paper having a moisture content of 4 to 6% immediately after opening the packaging. Is calculated from Water absorption (%) = (paper weight after 30 seconds−paper weight immediately after opening packaging) ÷ (paper weight immediately after opening packaging) The method of reducing the water absorption is to mix dry pulp such as LBKP and the like. It is also possible by adding an additive or surface sizing agent.

The pulp used in the present invention is virgin chemical pulp (CP: bleached hardwood kraft pulp,
Softwood bleached kraft pulp, hardwood unbleached kraft pulp,
Softwood unbleached kraft pulp, hardwood bleached sulphite pulp, softwood bleached sulphite pulp, hardwood unbleached sulphite pulp, pulp made by chemically treating wood and other fiber raw materials), virgin (MP: pulp produced by mainly mechanically processing wood and other fiber materials such as ground pulp, chemical ground pulp, chemimechanical pulp, and semi-chemical pulp).

Waste paper pulp and woodfree paper that have been dissociated from unprinted waste paper, such as paper cuts, waste paper, and width-reduced waste paper generated in bookbinding, printing factories, cutting shops, etc. , High quality coated paper, medium quality paper, medium quality coated paper, waste paper printed on flat paper, letterpress, intaglio printing, etc., electrophotographic method, thermal transfer method, ink jet recording method, carbon paper, etc. Oil-based ink, pulp (DIP), or the like, obtained by disintegrating waste paper or newspaper waste paper written with a pencil or the like and then deinking can also be used. Also, pulp treated with non-wood fibers such as bagasse, kenaf, bamboo, and rice leaf as raw materials can be used.

Fillers that can be used in the recording paper of the present invention include calcium carbonate such as heavy calcium carbonate, light calcium carbonate, chalk, and silicic acids such as kaolin, calcined clay, pyrophyllite, sericite, and talc. And inorganic pigments such as urea resin. When added, the content of ash (JIS-P-8128) is set to 5% or more to prevent back fogging. Also, if the ash content exceeds 23%, the amount of paper dust is likely to increase, so the content is set to 23% or less. Is preferred.

When the recording paper of the present invention is coated and used, various pigments used for ordinary general coated paper, for example, calcium carbonate such as heavy calcium carbonate, light calcium carbonate, chalk, kaolin, calcined Inorganic fillers such as silicic acids such as clay, pyrophyllite, sericite, and talc, and organic pigments such as urea resin can be used alone or in combination.

The adhesive used when coated and used is as follows:
Water-soluble adhesives, emulsions, latexes, etc., which have strong adhesion to additives such as base materials and pigments and have low blocking properties, can be used alone or in combination. For example,
Polyvinyl alcohol, modified polyvinyl alcohol,
Water-soluble resins such as starches, gelatin, casein, methylcellulose, hydroxycellulose, acrylamide / acrylate copolymers, acrylic emulsions, vinyl acetate emulsions, vinylidene chloride emulsions, and polyester emulsions can be used. It is not limited to these.

The coating method includes, for example, an on-machine coater provided with a coating device such as a gate roll coating, a size press coating, a blade coating, an air knife coating, a roll coating, a bar coating, and a reverse coating. Any of off-machine coaters such as roll coating, gravure coating, and curtain coating can be used.

Examples of the internal sizing agent used in the present invention include sizing agents such as rosin sizing agents, synthetic sizing agents, petroleum resin sizing agents, and neutral sizing agents. For example, an appropriate sizing agent and a fixing agent for fibers can be used in combination.
It is desirable to use a neutral sizing agent from the viewpoint of the running property in an electrophotographic copying machine, a printer, and the like and the paper storability after copying. Further, preparation of raw materials and control of production conditions are performed to impart electrophotographic aptitude such as copy aptitude and runnability.

The basis weight of the information paper of the present invention is 80 to 110.
g / m ² . 110g basis weight
If it exceeds / m ² , the heat capacity of the paper increases, and in a low-temperature environment, the toner cannot be sufficiently melt-fixed, and so-called cold offset occurs.
On the other hand, if the amount is less than 80 g / m ² , sufficient opacity cannot be obtained, and the image is likely to be fogged during double-sided copying. In addition,
A more preferred range of the basis weight is 90 to 105 g / m ² .

In order to prevent image disturbance and maintain an appropriate copy image density, a conductive agent such as sodium chloride, potassium chloride, a styrene / maleic acid copolymer, or a quaternary ammonium salt is used. The surface is coated with a press and the surface electrical resistivity of the information recording paper (JIS K69)
11) at 10 ⁸ to 10 ¹¹ Ω (temperature 20 ° C., humidity 65% R
H) is preferable. Further, in order to reduce the amount of generated paper dust, it is preferable to apply a water-based resin such as PVA to the surface by a size press.

In order to improve the sharpness of the copy image portion, the surface irregularities are reduced by a calendering process or the like.
Smoothness of information recording paper (JIS P 8119, TAP
PISTANDARD T479su-71) is set to 50 seconds or more, preferably 60 seconds or more, and is preferably set to 1000 seconds or less from the viewpoint of running performance. Also, the whiteness should be 80% or more, so that moisture absorption and desorption do not occur during storage.
It is preferable to wrap with moisture-proof wrapping paper such as polyethylene laminated paper or polypropylene film.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Example 1) Hardwood kraft pulp (LBK) beaten to a freeness of 470 ml CSF (Canadian standard freeness)
P) 30% of dry pulp and 70% of dry pulp were used as raw pulp for papermaking, and as shown below, papermaking chemicals and fillers were added in absolutely dry terms per pulp weight. Alkenyl succinic anhydride (ASA) 0.1% (National Starch and Chemical Co., Fine Bran 81) Cationized starch 0.5% (National Starch and Chemical Co., Kate F) Light calcium carbonate 15% Sodium chloride 0.3% This paper material is used to make paper with a Fourdrinier paper machine, passed through a size press mainly composed of oxidized starch, and a machine calender, and adjusted to a moisture content of 5.0% when opened. / M ² of recording paper.

The fiber orientation ratio was adjusted by changing the ratio of the material ejection speed / wire speed (J / W ratio). CD expansion and contraction rate of the obtained recording paper was 0.41%, water absorption was 0.52%,
The fiber orientation ratio was 1.20. Further, the incidence rate of image loss of the second side under a high temperature and high humidity environment was less than 1% as shown in Table 1, and there was no other image quality trouble.

[0034]

[Table 1]

The fiber orientation ratio was measured by a measuring instrument SST-210 (SONICSHETTE TESTE manufactured by Nomura Shoji Co., Ltd.).
R-210). Confirmation of missing images on the second side was performed in an environment of 30 ° C. and 85% RH according to the following procedure. The color copier uses Docu Color 4040 manufactured by Fuji Xerox Co., Ltd. 1
A copy original of the first side is a black-and-white original consisting of about 800 characters, and a color original (image density of 20%) including a pie graph is used as a part of the black-and-white original having an image density of 10% or less. As a copy original, a halftone original (image density: 20%) with a full gray surface was used. The paper size used in the evaluation was A3, and the number of copies was
For each type, 50 continuous copies were evaluated once.
Evaluation was performed twice in total (200 sheets in total). As a result, the occurrence rate was calculated from the number of occurrences of the image loss, and is shown in Table 1 as the second-side image loss rate.

Further, as other image quality trouble confirmation, the image area ratio 70 of each of black, yellow, magenta, cyan, red, green, blue, and mixed black of yellow, magenta and cyan,
80, 90, and 100% 20 mm × 20 mm patches were transferred and fixed on both sides of the recording paper, and image quality such as toner scattering and granular image omission was visually evaluated. Table 1 shows other image quality problems. Indicated. The experimental environment was 22 ° C. and 55% RH, and 10 ° C. and 20% RH.

(Example 2) In the stock preparation in Example 1, the blending ratio of LBKP was 10% and the dry pulp was 90%.
%, Replacing ASA with alkyl ketene dimer (AKD)
A recording paper having a moisture content at the time of opening of 4.3% and a basis weight of 81 g / m ² was obtained in the same manner as in Example 1 except that (Pine K-903, manufactured by Arakawa Chemical Industry Co., Ltd.) was used. The obtained recording paper had a CD expansion / contraction ratio of 0.37%, a water absorption ratio of 0.42%, and a fiber orientation ratio of 1.15. Further, the incidence rate of image loss of the second side under a high temperature and high humidity environment was less than 1% as shown in Table 1, and there was no other image quality trouble.

Example 3 In the stock preparation of Example 1, the blending ratio of LBKP was 25% and the dry pulp was 75%.
%, And a base paper having a moisture content at the time of opening of 4.5% and a basis weight of 82 g / m ² was obtained in the same manner as in Example 1 except that the content was changed to%. Also, the paint is prepared by adding a dispersant (sodium polyphosphate) to 100 parts by weight of water.
05 parts by weight, 80 parts by weight of cubic light calcium carbonate having an average particle diameter of 2 μm and 20 parts by weight of kaolin are dispersed, and 15 parts by weight of SBR as a binder and P are added.
VA was mixed in an amount of 5 parts by weight to obtain a paint. This paint is applied to both sides of the base paper by a coater so as to have a weight of 4 g / m ² per side, dried, calendered, and weighed 90 g / m ^2.
Recording paper was obtained. The obtained recording paper had a CD expansion / contraction ratio of 0.44%, a water absorption ratio of 0.50%, and a fiber orientation ratio of 1.3.
It was 0. In addition, as shown in Table 1, no image loss on the second side was observed in a high-temperature and high-humidity environment, and there was no other image quality trouble.

(Example 4) In the stock preparation of Example 1, the blending ratio of LBKP was set to 40% and the dry pulp was adjusted to 60%.
%, And ASA is neutral rosin size (Arakawa Chemical Co., Ltd.
A recording paper having a moisture content at opening of 5.3% and a basis weight of 90 g / m ² was obtained in the same manner as in Example 1 except that KS767) was used. The recording paper obtained had a CD expansion / contraction rate of 0.40%, a water absorption rate of 0.58%, and a fiber orientation ratio of 1.15. Further, as shown in Table 1, no loss of the second image in a high-temperature and high-humidity environment was observed, and there was no other image quality trouble.

Example 5 The same procedure as in Example 2 was carried out except that the blending of LBKP was stopped and the dry pulp was changed to 100% in the preparation of the stock material in Example 2.
Thus, a recording paper having a basis weight of 90 g / m ² was obtained. The recording paper obtained had a CD expansion / contraction ratio of 0.35%, a water absorption ratio of 0.41%, and a fiber orientation ratio of 1.10. Further, as shown in Table 1, no loss of the second image in a high-temperature and high-humidity environment was observed, and there was no other image quality trouble.

Example 6 The paper stock was adjusted in the same manner as in Example 4 to obtain a base paper having a basis weight of 94 g / m ² . Further, the coating material was adjusted in the same manner as in Example 3, and 5 parts per side was applied by a coater.
g / m ² , coated and dried on both sides of the base paper,
Calendered and opened with a moisture content of 4.1% and a basis weight of 104 g
/ M ² of recording paper. The obtained recording paper had a CD expansion / contraction ratio of 0.38%, a water absorption ratio of 0.55%, and a fiber orientation ratio of 1.10. In addition, as shown in Table 1, no image loss on the second side was observed in a high-temperature and high-humidity environment, and there was no other image quality trouble.

(Example 7) In the stock preparation in Example 2, the blending ratio of LBKP was adjusted to 50%, and dry pulp was adjusted to 50%.
%, And a recording paper having a moisture content at opening of 5.9% and a basis weight of 104 g / m ² was obtained in the same manner as in Example 2. The obtained recording paper had a CD expansion / contraction ratio of 0.44% and a water absorption of 0.1%.
The fiber orientation ratio was 60% and the fiber orientation ratio was 1.25. In addition, as shown in Table 1, no image loss on the second side was observed in a high-temperature and high-humidity environment, and there was no other image quality trouble.

(Example 8) In the stock preparation of Example 1, the blending ratio of LBKP was adjusted to 20% and the dry pulp was adjusted to 80%.
%, Except that the stock was adjusted in the same manner as in Example 1.
The paper is made with a twin wire paper machine, passed through a size press and a machine calender, and has a basis weight of 10 with a moisture content of 4.6% when opened.
4 g / m ² of recording paper was obtained. CD of recording paper obtained
The expansion ratio was 0.42%, the water absorption was 0.48%, and the fiber orientation ratio was 1.25. In addition, as shown in Table 1, no image loss on the second side was observed in a high-temperature and high-humidity environment, and there was no other image quality trouble.

(Comparative Example 1) In the stock preparation of Example 1, the blending ratio of LBKP was 70% and the dry pulp was 30%.
%, Except that the stock was adjusted in the same manner as in Example 1.
The paper was made with a fourdrinier paper machine and passed through a size press and a machine calender to obtain recording paper having a moisture content of 5.0% at the time of opening and having a basis weight of 81 g / m ² . The CD expansion / contraction ratio of the obtained recording paper is 0.
42%, water absorption rate was 0.71%, and fiber orientation ratio was 1.10. Further, as shown in Table 2, the incidence rate of missing images on the second side under a high temperature and high humidity environment was in the range of 5% or more and less than 10%.

[0045]

[Table 2]

(Comparative Example 2) In the stock preparation of Example 2, the blending ratio of LBKP was 30% and the dry pulp was 70%.
%, Except that it was changed to%.
The paper was made with a fourdrinier paper machine and passed through a size press and a machine calender to obtain recording paper having a moisture content of 6.4% when opened and a basis weight of 81 g / m ² . The CD expansion / contraction ratio of the obtained recording paper is 0.
The water absorption was 37%, the water absorption was 0.48%, and the fiber orientation ratio was 1.10. Further, as shown in Table 2, the rate of occurrence of missing images on the second side under a high temperature and high humidity environment was 10% or more.

(Comparative Example 3) In the stock preparation in Example 3, the blending ratio of LBKP was set to 40% and dry pulp was set to 60%.
%, Except that the stock was adjusted in the same manner as in Example 3.
The paper was made with a fourdrinier paper machine and passed through a size press and a machine calender to obtain transfer paper having a moisture content of 6.0% when opened and a basis weight of 90 g / m ² . The CD expansion / contraction ratio of the obtained recording paper is 0.
47%, water absorption was 0.56%, and fiber orientation ratio was 1.35. Further, as shown in Table 2, the incidence rate of missing images on the second side under a high-temperature and high-humidity environment was in the range of 1% or more and less than 5%.

(Comparative Example 4) In the stock preparation of Example 4, the blending ratio of LBKP was changed to 1 by stopping the blending of dry pulp.
Except for changing to 00%, the paper stock was adjusted in the same manner as in Example 4, paper-made with a fourdrinier paper machine, passed through a size press and a machine calender, and opened at a moisture content of 4.1% and a basis weight of 90 g / m2.
² recording papers were obtained. The obtained recording paper had a CD expansion / contraction ratio of 0.61%, a water absorption ratio of 0.75%, and a fiber orientation ratio of 1.4.
It was 5. Further, as shown in Table 2, the rate of occurrence of missing images on the second side under a high temperature and high humidity environment was 10% or more.

(Comparative Example 5) In the stock preparation of Example 5, the blending ratio of LBKP was adjusted to 80% and the dry pulp was adjusted to 20%.
%, Except that the stock was adjusted in the same manner as in Example 5.
The paper was made with a fourdrinier paper machine and passed through a size press and a machine calender to obtain recording paper having a moisture content of 3.5% when opened and a basis weight of 90 g / m ² . The CD expansion / contraction ratio of the obtained recording paper is 0.
The water absorption was 44%, the water absorption was 0.72%, and the fiber orientation ratio was 1.10. Further, as shown in Table 2, the incidence rate of missing images on the second side under a high temperature and high humidity environment was in the range of 5% or more and less than 10%.

(Comparative Example 6) In the stock preparation of Example 7, the blending ratio of LBKP was adjusted to 50% and dry pulp was adjusted to 50%.
%, Except that the stock was adjusted in the same manner as in Example 7.
It is made with a Fourdrinier paper machine, passed through a size press and a machine calender, and opened at a moisture content of 6.1% and weighed at 104 g / m ^2.
Recording paper was obtained. The obtained recording paper had a CD expansion / contraction ratio of 0.48%, a water absorption ratio of 0.59%, and a fiber orientation ratio of 1.3.
It was 5. Further, as shown in Table 2, the rate of occurrence of missing images on the second side under a high temperature and high humidity environment was 10% or more.

(Comparative Example 7) In the stock preparation in Example 7, the blending ratio of LBKP was 60% and the dry pulp was 40%.
%, Except that the stock was adjusted in the same manner as in Example 7.
It is made with a twin wire paper machine, passed through a size press and machine calender, and opened with a moisture of 6.2% and a basis weight of 10
4 g / m ² of recording paper was obtained. CD of recording paper obtained
The expansion ratio was 0.45%, the water absorption was 0.65%, and the fiber orientation ratio was 1.15. Further, as shown in Table 2, the rate of occurrence of missing images on the second side under a high temperature and high humidity environment was 10% or more.

[0052]

According to the present invention, there is provided an information recording sheet which is excellent in the suitability for double-sided full-color copying without the loss of the second-side image and the image quality trouble at the time of double-sided copying in a full-color copying machine / printer by adopting the above configuration. Enabled.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a change in heat roll temperature during continuous copying and a rate of occurrence of missing images on a second surface.

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[Procedure amendment]

[Submission date] March 27, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording sheet capable of obtaining a high-quality image on both sides when printing on both sides of an electrophotographic copying machine or a printer, and having no image loss.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION To solve the above problems, the present inventors have intensively studied to prevent image loss during double-sided full-color copying, particularly image loss on the second side during double-sided copying under high temperature and high humidity. The image missing was caused by a copy machine with a high continuous copy speed (sheets / minute), especially when a low image density original consisting of characters etc. was used on the first side and the image was It was confirmed that the problem occurred remarkably at the trailing edge of the paper when using an original having, and it was particularly likely to occur on several sheets immediately after the start of copying.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

In the present invention, the water absorption isPaper moisture content
4. 0~ 6. 0% Paper, 30 ° C, 85% RH
Measure the increase in paper weight immediately after opening the package
Then, it is calculated from the following equation. Water absorption (%) = (paper weight after 30 seconds-immediately after opening the package
(Weight of paper) 用紙 (weight of paper immediately after opening packaging) The method of reducing the water absorption is to use a dry paper such as LBKP.
For addition of internal sizing agent and surface sizing agent in addition to compounding
Therefore, it is also possible.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Waste paper pulp and woodfree paper that have been dissociated from unprinted waste paper, such as paper cuts, waste paper, and trimmed waste paper generated in bookbinding, printing factories, cutting mills, etc. , High quality coated paper, medium quality paper, medium quality coated paper, flat paper, letterpress, intaglio printing, etc., and electrophotographic method, thermal transfer method, ink jet recording method, used paper printed with carbon paper, etc., and aqueous, Oil-based ink, pulp (DIP), or the like, obtained by disintegrating waste paper or newspaper waste paper written with a pencil or the like and then deinking can also be used. Also, pulp treated with non-wood fibers such as bagasse, kenaf, bamboo, and rice leaf as raw materials can be used.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

[0034]

[Table 1]

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

(Example 4) In the stock preparation of Example 1, the blending ratio of LBKP was set to 40% and the dry pulp was adjusted to 60%.
%, And ASA is neutral rosin size (Arakawa Chemical Co., Ltd.
A recording paper having a moisture content at the time of opening of 5.3% and a basis weight of 90 g / m ² was obtained in the same manner as in Example 1 except that KS767) was used. The recording paper obtained had a CD expansion / contraction rate of 0.40%, a water absorption rate of 0.58%, and a fiber orientation ratio of 1.15. The dihedral th partial deletion in a high-temperature and high-humidity environment is not observed as shown in Table 1, there was no other quality problems.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

Example 5 The same procedure as in Example 2 was carried out except that the blending of LBKP was stopped and the dry pulp was changed to 100% in the preparation of the stock material in Example 2.
Thus, a recording paper having a basis weight of 90 g / m ² was obtained. The recording paper obtained had a CD expansion / contraction ratio of 0.35%, a water absorption ratio of 0.41%, and a fiber orientation ratio of 1.10. The dihedral th partial deletion in a high-temperature and high-humidity environment is not observed as shown in Table 1, there was no other quality problems.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

[0045]

[Table 2]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaru Kato 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. (72) Inventor Harumi Watanabe 1-10-6, Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. In the formula company

Claims (4)

[Claims] 1. The paper moisture content immediately after opening is 4.0 to 6.0.
%, The CD expansion / contraction rate is 0.45% or less, and 30 ° C.
An information recording sheet characterized by having a water absorption of 0.6% or less 30 seconds after opening immediately in an 85% RH environment. 2. The recording paper according to claim 1, wherein the dry pulp contains at least 50% of the total pulp weight.
Information recording paper described. 3. The information recording sheet according to claim 1, wherein the fiber orientation ratio of the recording sheet is 1.30 or less. 4. An information recording sheet, wherein the information recording sheet according to claim 1 is used for double-sided printing.