JPS63309700A - Copy paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to copy paper, and more particularly to copy paper that can be used both as dry PPC paper in the electrophotographic field and as printing paper in the 11-honsha printing field.

(Conventional technology) First, the conventional technology of electrophotographic paper will be described.

As electrophotographic paper, the paper tension is 0.65 to 0.72q.
/Cm' has been proposed to reduce fixing wrinkles by self-absorbing shrinkage stress during drying and wet expansion stress during high humidity in the fixing section (Japanese Patent Laid-Open No. 17385/1985).

However, when the tension is 0.65 to 0.72 (J/cm'), the Bekk smoothness is less than 30 seconds, and some electrophotographic papers are manufactured with a smoothness in the 40 second range, but in both cases the surface roughness of the paper There are problems in that it is inferior in quality, feels rough to the touch, and has a poor texture as paper.

There is also a proposal to reduce the wet expansion stress at high humidity by setting the moisture content of paper to 5.5 to 7.0%. However, when the moisture content is as high as 5.5 to 7.0%, the amount of moisture absorbed at high humidity is small, and moisture unevenness (moisture difference) within the paper is small, which is advantageous in terms of fixing wrinkles, but as a side effect. (1) Due to dehumidification in low humidity conditions, paper curls before copying become larger and paper jams occur more often. (2) Paper curls become larger after copying due to shrinkage due to large dehumidification during heat fixing, resulting in poor running quality (jams, stock Problems arise such as poor performance (sexuality, hearing ability, etc.).

In addition, fillers (clay, talc, calcium carbonate, etc.)
There is a proposal to suppress the hygroscopicity (rate) by incorporating ~12% (weight ratio of pulp), and further suppress the bonding between mm and mm by using a filler to provide voids in the paper to reduce shrinkage and expansion forces. but,
When the amount of filler added is as high as 8 to 12%, problems arise in that paper strength (mainly stiffness, stiffness, Clark stiffness) decreases and running quality (jamming, stockability) is poor.

Furthermore, the freeness (pulp beating degree) is increased to slow down (insensitize) the moisture absorption rate of the fibers, and to provide voids between the fibers so that the wet expansion stress at high humidity can be self-absorbed. There are proposals to reduce fixing wrinkles and post-copy curl. However, when the freeness is increased, the smoothness and tightness of the paper disappear, resulting in a bulky paper that feels rough to the touch.
I'm angry.

Next, the prior art of mimeograph paper will be described.

It is no exaggeration to say that most of the paper currently produced in large quantities is made for the purpose of printing.

Printing paper is generally classified as follows.

Printing paper A: 100% high-quality academic pulp...Printing paper for books, textbooks, posters B: 70% chemical pulp medium-quality paper...Printing paper for books C: Chemical pulp 70-b Printing for telephone directory Paper D: Chemical pulp 4 overprinting, low-grade printing paper The quality required for printing paper is generally referred to as "printability" and can be roughly divided into the following two types.

Print quality: ink density, resolution, uneven printing, gloss, handling, ink stains, print workability: paper jam (printing cylinder wrapped), uneven paper output, poor paper feed (misfeed, large number of sheets) In the case of the above printing paper A, it is manufactured with emphasis on the surface properties of the paper in order to improve the resolution, printing unevenness, gloss, etc. of printed matter quality, and the physical properties of the paper include a density of 0.
．． 74Q7cm or more, air permeability 16 seconds or more, ash content 8-20
There are many papers that are relatively dense. When these printing papers are used in a mimeograph machine, the printing ink absorbs and dries at a slow rate, so if they are stacked one on top of the other, the back side will be smeared with ink from the paper underneath.

On the other hand, in the case of stencil printing paper, the air permeability is lowered to increase the printing ink absorption and drying speed, and the smoothness is also lowered to J3. Many of these papers are relatively rough, with an air permeability of 15 seconds or less and a Bekk smoothness of 30 seconds or less.However, although the printing quality of these printing papers is good, the feel of the paper is rough and rough, and There is a problem that paper dust is generated during printing.

(Purpose) The present invention has been made in view of the above points, and its purpose is to:
When used as electrophotographic paper in an electrophotographic device (dry type PPC copying machine) that has a heat roll type heat fixing unit, (1) curling after copying is small, jams, smearing, etc. are less, and running quality is improved. The purpose of the present invention is to provide paper that (2) has fewer fixing roll wrinkles (heat roll wrinkles) that occur in a copying machine.

Another purpose is that when used in a mimeograph machine as a highly white paper belonging to printing paper, (1) the back side of the paper will not be smeared with ink from the paper below even if it is stacked one after another during printing; (The ink sinks into the paper and dries up.) (2) Is the separation between the copper plate and paper good during printing, and does the ink get smeared by wrapping around the copper plate or coming into contact with the separating claw? (3) Improved paper that has less ink stains, (3) gives the impression of high-quality paper that is similar to that of high-quality paper, and has a good texture without the roughness of the paper texture like stencil paper. It is about providing.

(Structure) In order to achieve the above object, the present invention provides chemical pulp 1
00%, the following properties (a) to (g) within the basis weight range of 64 to 70 fl/m: (a) Thickness: 91 to 91μ surface (b) Density: 0.69 to 0.73 g/cm ”(c)
Beck smoothness (front) 30-55 seconds, (back) 30-55 seconds (d) Air permeability 15 seconds or less (e) Clark stiffness (side)
25Cm3/100 or more (to) ash content
4-8% (g) Moisture 4.3-5.
5%.

In a heat-fixing dry PPC copying machine with a heat roll system, after the image on the photoreceptor drum is transferred to paper,
The image is fixed by passing it through a fixing roll equipped with a heater on the image surface or both the image surface and non-image surface. At this time, the cellulose W4 on the copy paper shrinks due to water dehumidification due to the heat from the heater.At this time, if there is a moisture difference in the short and long directions of the copy paper, there will be a difference in shrinkage, resulting in uneven shrinkage. occurs.

When the shrinkage difference reaches a limit that cannot be self-absorbed inside the paper, the stress is concentrated at one location on the paper as it passes through the fixing roll, causing wrinkles coaxial with the passing direction (perpendicular to the fixing roll). From now on, we focused on the moisture difference (moisture unevenness) within a single sheet of paper in a particularly high-humidity environment, and found that paper that wrinkles in the fusing section of a copying machine has various factors such as moisture content ω, tightness, air permeability, etc. It was found that it is determined by a combination of physical properties.

Therefore, the present inventor has developed an electrophotographic paper that (1) only needs to adjust the moisture content, tightness, and air permeability to prevent fixing wrinkles, (2) satisfies curling and runnability after copying, and I came up with the idea that in order to maintain the feel of paper, it is sufficient to have a good ash content, size, and smoothness.

In addition, as mimeograph paper, (1) it only needs to satisfy air permeability, tightness, and ash content to prevent ink stains on the back side after printing, and (2) preparation during printing and separation from paper. 1, (3) Clark stiffness should be increased to avoid ink stains due to contact with separation claws.
) It has been found that in order to improve the texture of paper, it is necessary to increase the smoothness and tightness.

Next, the requirements that the copy paper of the present invention should have will be explained.

The thickness of the copy paper of the present invention is necessarily in the range of 91 to 97μ. If it is less than 91 μm, it will lose its texture as paper;
If it exceeds .mu.m, it will give the impression of thick paper, giving a bad image as paper, and the number of sheets stored in the paper feed tray will decrease.

Density (tightness) ranges from 0.69 to 0.73 C1/cm.

If it is less than 0.69 g/ci, the surface of the paper will become rough and the texture will be poor, and if it exceeds 0.73 g/, 7',
Although the paper becomes denser and feels better to the touch, (8) for electrophotography, shrinkage of fibers due to moisture absorption and dehumidification,
Self-absorption tolerance is low when expansion changes occur, and wrinkles occur in the fixing roll at high humidity. In addition, there is a problem that the rounded part of the toner causes the phenomenon of kokkuri (upper brush), which causes small irregularities on the paper. The problem is that the absorption and drying properties are low, and ink back staining occurs or becomes worse. Density 0.69-0.73CJ
/cm range (in order to achieve this, the raw material should be coarsely beaten, the pressure applied by the press section should be reduced, and the pressure applied by the calender should be reduced.

Bekk smoothness is in the range of 30 to 55 seconds (both in appearance). If it is less than 30 seconds, the surface will feel rough when touched by hand, and the texture will be poor. If it is more than 55 seconds, the pore force of the paper surface will be low, the ink absorption and drying performance will be low, and ink stains will occur on the back side. becomes terrible.

The air permeability of the copy paper of the present invention is required to be 15 seconds or less.

If the time exceeds 15 seconds, the ink absorption and drying properties of the paper for mimeograph printing will be low, and the back side of the paper will become heavily stained.

In order to reduce the air permeability to 15 seconds or less, the raw stone should be made coarser and the pressure applied at the press section should be lowered.

Clark stiffness (lateral) is 25 cmJ/100 or more.

If it is less than 25 cmJ/100, there is no "paper stiffness", so the separability from the copper plate becomes poor in mimeograph printing, and the paper wraps around the copper plate or comes into contact with the separating claw.

In order to make the Clark stiffness (lateral) 250 m3/100 or more, the basis weight should be 60 g/m or more, the raw material should be coarsely beaten,
The amount of filler added may be reduced.

Ash content is 4-8% (by weight). If it is less than 4%, the stiffness of the paper becomes high, but the surface properties deteriorate and the resolution of copied and printed images deteriorates. If it exceeds 8%, the filler will fill the voids between fibers on the surface of the paper, improving the surface properties (smoothness) of the paper and improving image quality such as resolution and ink density. As the fiber ratio decreases, the stiffness of the paper (Clark stiffness) decreases, making it easier for the copper plate to wrap during printing.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1, Comparative Examples 1 to 4 The following manufacturing recipe was used.

(A> L-BKP 100% with freeness 500C3r (B
) Internally added chemicals include talc 8% (weight ratio to pulp), rosin sizing agent 1%, sulfuric acid band 5%, surface sizing agent oxidized starch 0.5g/7rt, NaClO,2
5% Then, set the press pressure as low as possible at 10 to 40 kg/rri, and use the calender's own weight to make Fourdrinier paper.
I made paper from cardboard.

The above characteristics of the product (a), (b), (c), (d) (e)
, (F), (G) and other physical properties are shown in Table 1.
Table 2 shows the evaluation results when printed using an RPC copier and a mimeograph machine.

In addition, paper with the same composition but different physical properties was used in Comparative Example 1.2.
．． 3 as shown in Tables 1 and 2.

(Effects) As is clear from the above explanation, the copy paper of the present invention has the following effects:
When used as electrophotographic paper in an electrophotographic device (dry type RPC copying machine) that has a heat roll type heat fixing section, (1) curling after copying is small, jams, smearing, etc. are less, and running quality is satisfied. However, the number of sheets stored in the sorter is large, and (2) it exhibits excellent properties such as fewer fixing roll wrinkles (heat roll wrinkles) that occur in copying machines.

In addition, when used in a mimeograph machine as a highly white paper belonging to printing paper A, (1) the back side of the paper will not be smeared with ink from the paper below even if it is stacked one after another during printing (the ink will not be stained by the paper below). (2) The printing plate and paper are well separated during printing, and the ink does not get smeared by wrapping around the printing plate or coming into contact with the separating claw, or the ink (3) The paper does not have a rough feel like stencil paper, giving an image of high-quality paper like high-quality paper, and exhibits excellent properties such as a good texture.

Claims (1)

[Claims] Made of 100% chemical pulp, basis weight 64-70g/m^
The following characteristics (a) to (g) within the range of 2: (a) Thickness 91 to 97 μm (b) Density 0.69 to 0.73 g/cm^3 (c) Bekk smoothness (table) 30 to 55 seconds, (back) 30-55 seconds (d) Air permeability 15 seconds or less (e) Clark stiffness (side) 25cm^3/100 or more (f) Ash content 4-8% (g) Moisture 4.3-5 Copy paper characterized by comprising .5%.