JPH11338181A - Transfer paper for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer paper for electrophotography comprising blended used-paper pulp by which running and operative properties are improved in copying machines. SOLUTION: A transfer paper for electrophotography comprising blended used paper pulp is characterized in that a difference (M1 -M2 ) between an equilibrium water content (M1 %) after moistened for 12 hours at a relative humidity of 65% and a temp. of 20 deg.C and an equilibrium water content (M2 %) before moistened is 2.5% or less and that curling after copying is 32 mm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer paper for electrophotography, and more particularly, to a transfer paper used in an electrophotographic copier for heat-fixing a toner, whereby the transferability and workability of the transfer paper are improved. The present invention relates to an electrophotographic transfer paper containing waste paper pulp.

[0002]

2. Description of the Related Art Transfer paper used in an electrophotographic copying machine is characterized by its running property and workability, especially in terms of paper dust trouble occurring at the time of copying and curling trouble of the copying paper occurring after copying. Virgin pulp has been used exclusively. In recent years, wastepaper pulp has come to be used for transfer paper for electrophotography from the viewpoint of resource depletion and environmental problems. A method of deinking waste paper pulp
As described in JP-A-52-20563 and JP-B-61-11353, improvements in the efficiency of deinking have been proposed. Further, the use of waste paper pulp for transfer paper for electrophotography is disclosed in JP-B-63-6687, JP-A-58-40556 and JP-A-59-17558. Improvements in antistatic properties, running suitability, fixing stability of toner, and the like as paper have been proposed.

[0003] However, as is well known, when used paper pulp is used as a raw material for electrophotographic transfer paper, a problem associated with recycling of used paper is that pulp fibers are exposed to oxygen in the air while the paper is used. Deterioration under the influence of heat, temperature, light, etc., subject to mechanical external force during defibration, beating, papermaking, karengu, printing, processing, etc., and sizing, coating, printing, resin processing Since the paper is degraded due to a chemical action during the application of an adhesive or the like, the obtained transfer paper has keratinized pulp fiber cells as described in the above-mentioned publications, and the pulp fiber becomes “ Because of the "curved" condition, paper powder is likely to generate paper dust and equilibrium moisture is different from that from virgin pulp, so naturally it is easy to generate curling wrinkles , Workability and running properties has a problem such inferior compared to those of the transfer paper made from only virgin pulp.

[0004]

In view of the above situation, the present inventor has used a pulp blended with waste paper pulp to change the level of paper moisture during papermaking and to obtain an electrophotographic transfer paper after transfer. As a result of intensive studies on the curl properties, wrinkle occurrence, etc., the difference between the equilibrium moisture of the paper after humidity control and the moisture of the paper before humidity control significantly affects the curl of paper, wrinkles, runnability and workability. To complete the present invention. Accordingly, an object of the present invention is to provide an electrophotographic transfer paper in which, when a transfer paper containing waste paper pulp is used in an electrophotographic copying machine, curling and wrinkles are reduced, and travelability and workability are significantly improved. To provide.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an electrophotographic transfer paper containing waste paper pulp, wherein the relative humidity is 65%.
Equilibrium moisture (M ₁₎ of paper after conditioning for 12 hours at a temperature of 20 ° C.
%) And the water content (M ₂ %) of the paper before humidity control (M ₁ −
M ₂ ) is within 2.5% and the curl after copying is 32 m
m or less, which is an electrophotographic transfer paper. In addition, the present invention provides that the content of the waste paper pulp is 60%.
The present invention relates to the transfer paper for electrophotography described above.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As waste paper for waste paper pulp used in the present invention, in addition to high quality waste paper such as newspaper waste paper and flyers, transfer paper for electrophotography, foam paper, carbonless paper,
Broken papermaking of used office paper, such as thermal recording paper, and paper is also included. As is well known, these waste papers are pulverized in a pulper with the intervention of water and dispersed in water. During the disintegration of waste paper, a deinking agent consisting of 0.1 to 0.5% by weight of caustic soda and 0.1 to 0.3% by weight of surfactant per pulp is usually added, and this deinking process requires 15 to 60 minutes. Since the pulp slurry dispersed here contains the ink carbon and the colored pigment, the pulp and the ink component are deinked by a flotation method or a washing method. In the present invention, any known method is used. Can be

However, with this treatment alone, for example, in the case of waste newspaper, the whiteness of the obtained pulp is at most 40.
Because it is as low as ~ 45% and cannot be used as a raw material for electrophotographic copying paper, it is usually bleached with an oxidizing bleach such as hydrogen peroxide or sodium peroxide to finish pulp having a whiteness of 60% or more. As an alkali source for bleaching waste paper pulp with hydrogen peroxide, caustic soda and sodium silicate are used at a fixed ratio as in the conventionally known method. Bleaching may be carried out in a pulper or separately in a bleaching tower,
Generally, a pulp concentration of 5-40% by weight of 1.
0 to 5.0% by weight hydrogen peroxide addition rate, 1.0 to 4.0% by weight
The treatment conditions are as follows: sodium hydroxide addition rate, sodium silicate addition rate of 1.0 to 3.0% by weight, temperature of 30 to 70 ° C., and holding time of 30 to 240 minutes.

In the present invention, the waste paper pulp thus obtained may be a softwood bleached kraft pulp, if desired.
The paper is made in a paper machine together with other pulp such as bleached hardwood kraft pulp, and a conventionally known paper machine can be applied as it is.

It is already known that the equilibrium water content of paper varies depending on the type of pulp, the blending ratio, the degree of beating, the presence or absence of fillers, etc., and is slightly increased by adding inorganic substances such as clay and talc. However, the transfer paper conditioned at 65% relative humidity and a temperature of 20 ° C for 12 hours has an equilibrium water content in the range of 7.8 to 9.2%. .

On the other hand, the water content of the paper before humidity control is already determined when the paper is wound on a reel during papermaking. The higher the level of the water content, the more strict the conditions for adjusting the profile of the paper must be. It becomes difficult for papermaking technology.
Lowering the paper moisture level on the reel when paper is made can ease the above-mentioned conditions of the paper profile, wet press, and calender, and can obtain apparently uniform paper quality. But sensitive to external humidity,
Particularly in a season where the relative humidity is high, curling troubles due to moisture absorption of the paper are caused, which is not preferable. For this reason, the paper moisture before humidity control is currently controlled at about 5%.

The transfer paper of the present invention has a relative humidity of 65% and a temperature of 20 ° C.
Within the difference 2.5% between the lower at 12 hours tone-moist after paper equilibrium moisture (M _1%) and humidity the paper before water (M _2%), and so preferably a 1.5 to 2.4% The papermaking conditions and the drying conditions are adjusted to determine the moisture content of the paper before humidity control. Wrinkling occurs in a copying machine in which this moisture difference is larger than 2.5%, the curl of the paper becomes extremely large, and the workability and running performance in the copying machine are undesirably deteriorated. The lower limit of the moisture difference is ideally 0, but even if the inorganic material is added to lower the equilibrium moisture level and the paper moisture on the reel is increased by making full use of papermaking technology, the moisture difference is ideal. There is a limit to maintaining the state,
In the present invention, the purpose can be sufficiently achieved if the water difference is 1.5%, so it is not necessary to forcefully reduce the water difference to 1.5% or less.

In order to obtain the transfer paper of the present invention, the papermaking conditions such as the degree of beating of the pulp, the jet wire ratio, the profile, the press, the calender and the like are adjusted, and the drying conditions include the vapor pressure in the paper machine dryer and the drying conditions. Although the ventilation method is adjusted in various ways, it is very difficult to specify these conditions numerically because there are appropriate conditions for each paper machine, but a known method is applied as it is.

[0013]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but it should be understood that the present invention is not limited by these examples.

Examples 1 to 5 and Comparative Examples 1 to 5 70% by weight of used newspaper and 30% by weight of high-quality used paper such as flyers were used as used paper for used pulp. Hunter brightness of recycled paper pulp is 68.5%, and freeness is 185 ml
CSF (Canadian Standard Freeness) mixes this waste paper pulp with free hardened bleached kraft pulp to 410 ml C.SF at a fixed ratio, and then adds the following papermaking chemicals in absolute dry weight per pulp to make papermaking paper. Created a fee. Alkenyl succinic anhydride (Fibran 81, manufactured by Oji National) 0.09% by weight Cationized starch (Kate F, manufactured by Oji National) 0.5% by weight Sulfuric acid band 0.2% by weight Light calcium carbonate (TP-121S, manufactured by Okutama Industries) 11.0% by weight

[0015] Using this stock, a fourdrinier paper machine is used to make a paper, which is then passed through a size press and a machine calender to obtain a rice tsubo of 64 g / m2.
^2. Density 0.7g / cm ³ , Moisture on paper reel 5.O
Transfer paper with a changed level in the range of ~ 7.0% was obtained. Size press chemicals include starch for size press (oxidized starch,
Oji Ace B, Oji Cornstarch) and styrene-maleic acid copolymer (Polymalon 385, Arakawa Chemical)
Used in a ratio of 5: 0.2, the amount of this mixture applied to paper is 1.0
g / m ² . 65% relative humidity of the resulting transfer paper (A ₄ size paper), to evaluate the curl and wrinkle occurrence of the copier after humidity 12 hours conditioned at a temperature 20 ° C., and the results are shown in Table 1.

[0016]

[Table 1]

[0017] The evaluation of (transfer paper evaluation) of the transfer sheet of curling and wrinkling of the copying machine occurs, manufactured by Fuji Xerox Co., Ltd. of the electrophotographic copying machine (Model: 5990, sorter with) A ₄ edition of the transfer paper in Was copied 1000 times.

(1) Curling As shown in FIG. 1, a piece of curled transfer paper is grasped by hand, and the height (L) of an arc on the opposite side is read.
The average value of the reading values of the sheets was shown. The curl increases as the height of the arc increases. (2) Wrinkles Table 1 shows the ratio of the number of wrinkles out of 150 sheets of transfer paper copied. As can be seen from Table 1, the transfer paper of the present invention, in which the difference between the equilibrium moisture of the paper after humidity control and the moisture of the paper before humidity control is within 2.5% and the curl after copying is 32 mm or less, is wrinkled. There is no occurrence and the occurrence of curl is extremely small.

[0019]

According to the present invention, in an electrophotographic transfer paper containing waste paper pulp, the difference between the equilibrium moisture of the paper after humidity control and the moisture of the paper before humidity control is adjusted to within 2.5%, and When the curl after copying is 32 mm or less, the running and workability of the transfer paper in a copying machine are improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the measurement of curl after copying a transfer sheet.

[Explanation of symbols]

 1: Curl L (mm) of transfer paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sakuyoshi Miyabayashi 1 Oji-cho, Kasugai-shi, Aichi Prefecture Oji Paper Co., Ltd. Kasugai Mill

Claims (2)

[Claims] 1. An electrophotographic transfer paper containing waste paper pulp blended at 12% under a relative humidity of 65% and a temperature of 20 ° C.
The difference (M ₁ −M ₂ ) between the equilibrium moisture (M ₁ %) of the paper after humidity control and the moisture (M ₂ %) of the paper before humidity control is within 2.5%, and after copying. An electrophotographic transfer paper having a curl of 32 mm or less. 2. The transfer paper for electrophotography according to claim 1, wherein the blending amount of the waste paper pulp is 60% or more.