JPS6025783B2 - Electrophotographic transfer paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic transfer paper, and more particularly to an electrophotographic transfer paper in which a specific crab light dye is coated on the surface of the base paper or is present inside the base paper.

In normal transfer electrophotography, an electrostatic tank image is formed on a selenium photoreceptor, and after this is developed with colored resin particles (toner),
A means is employed for transferring the obtained toner image onto a transfer paper (image receiving paper) and further thermally fixing the transferred image.

The transfer paper (transfer paper for electrophotography) used here is mostly plain paper. However, in addition to plain paper, there are also transparent paper (plain paper impregnated with a resin solution and dried), transparent plastic film, and matte (combined) film (transparent plastic film surface treated physically or chemically). Depending on the purpose, a matte layer is formed by coating the surface with a resin solution containing a matting agent such as silica or glass powder and drying it. By the way, as a measure to increase the image density and contrast of copies, it is possible to add a crab light dye to the transfer paper or to coat the surface of the transfer paper with a crab light dye. However, when many crab light dyes are used, it is often observed that white spots occur in the image area at high temperatures and the background density becomes high. The above-mentioned "crab light dyes that have been proposed so far" are:
Typically, it refers to crab light dyes having a chemical structure such as bis-stilbene sulfonic acid type, coumarin type, pyrazoline type, naphthalimide type, bis-benzoxazole type, and bis-styrylbiphenyl type.

The present invention was made based on the finding that when a specific waxy dye is used, a high visual whiteness and good image contrast can be obtained without the above-mentioned defects. It is.

The present invention provides an electrophotographic transfer paper characterized in that a bisaminostilbene sulfonic acid type crab light dye is internally added or coated using a size press.

To explain the present invention in more detail below, the preferable compound of the bisaminostilpenesulfonic acid type crab light dye used in the transfer paper of the present invention has the following general formula (where X is chloro, hydrogen, or lower alkyl group). Alternatively, Y represents hydrogen or a lower alkyl group, and x and Y may be the same group or different groups.

M is a cation and represents hydrogen, an alkali metal or an alkali metal. ), and those in which M is sodium are particularly preferred. In addition to the general formula mentioned above, by using a halo dye to whiten the hue of the transfer paper, the image contrast will be improved and the apparent quality of the copy will be improved. That's to be expected for some reason.

However, as mentioned above, when many crab light dyes are used in transfer paper, white spots often occur in the image area at high temperatures. The "white spots in the image area" referred to herein is a phenomenon in which the toner image is not completely transferred from the transfer drum to the transfer paper, resulting in an unclear image. According to studies conducted by the present inventors, it has become clear that there are several factors contributing to the occurrence of this white spot phenomenon.

For example, the '1' transfer paper itself absorbs moisture and its volume resistance value decreases. The volume resistivity of atoms made as transfer paper is 1×1 at 20°C, 60% RH, and 5-6% moisture.
This is about 3 pi○, and 5 at 90% RH.
×1 bi. ○Approximately skin level. In general, 5×1 BiQ guy ~ 9×
When it becomes less than 1 p○m, the whiteout phenomenon will occur,
It also occurs due to local unevenness in the base paper. ■As already mentioned, this white spot phenomenon is more likely to occur when a large amount of crab light dye is used in the transfer paper, and this phenomenon is often seen when the mirror orientation is high humidity. This is thought to be because the crab light dye used here has increased hygroscopicity for some reason. Therefore, in the present invention, by using a specific pisaminostilbene sulfonic acid type fin photodye, the above-mentioned disadvantages can be prevented, and at the same time, the objects of the present invention can be achieved.

A detailed study has not yet been made as to why such excellent effects are exhibited only when a bisamino-stilbene sulfonic acid type crab-light dye is used. However, when using the dye represented by the formula below, which has a relatively similar structure to the compound represented by the general formula above, a noticeable white spot phenomenon was observed at high humidity. It is easy to infer that this is largely dependent on the chemical structure of the photodye.

When actually manufacturing the transfer paper according to the present invention, it is a prerequisite that the paper obtained has good runnability, non-rubber properties, and copy quality in accordance with the characteristics of a transfer type electrophotographic copying machine. There needs to be. The method for manufacturing the transfer paper of the present invention is similar to that for general high-quality paper. When using crab light dye in the papermaking process, there are two methods: (i) an internal addition method in which it is added during pulp separation or beating, and an external addition method in which it is impregnated (coated) with the size press liquid in the dish size press process. be.

Among these methods (hada i), method {ii) is more advantageous because the crab light dye spreads well on the surface of the base paper and produces a white effect even when a small amount is used. The amount of crab light dye used is
Although it varies depending on the desired degree of whiteness or the type of crab light dye, about 0.3 to 1 kg of tano base paper is suitable.

An amount less than 0.3 m/lk9 of base paper is insufficient to obtain good image contrast.

As the amount of crab light dye added increases, the whiteness also increases, but 3
Evening: When the amount of raw paper exceeds 1 kg, a quenching phenomenon (a phenomenon of shifting to yellow) begins to be observed. As is clear from the above, this quenching phenomenon that shifts to the yellow side occurs when an excessive amount of dye is present. It is thought that this can be done by preventing the color development of the crab light dye that is present, and by emphasizing the yellowish color of the crab light dye itself. The pulp composition as a base paper formulation is LBKP90.
-100%, NBKPO -10% is suitable.

This pulp blending ratio is the same or almost the same as that of general high-quality paper. The raw pulp is disintegrated in a pulper, then deluxe refiner, super refiner,
Beatness level is 410-490c with Norifiner such as Jordan.
The pulp slurry is beaten into pulp slurry, and this pulp slurry is made into paper using a paper machine. Note that addition of fillers, sizing agents, sulfuric acid, paper strength enhancers, etc. is carried out in the chest after beating the pulp slurry. The amounts of these additives are 5 to 1% by weight of clay, talc, etc. as a filler, 0.5 to 4.0% by weight of anionic emulsion size as a sizing agent, based on the prepared pulp slurry.
Sulfate band 1.0-5. Approximately 5 to 1% by weight of the polyacrylamide resin as a paper strength enhancer is appropriate. The blending ratio of these various additives is determined because the copy running properties of electrophotographic transfer paper depend on the stiffness of the base paper, and the size properties, surface smoothness, etc. also depend on the base paper. It was established to meet the requirements.

Further, when the crab light dye is added for internal addition, it is preferable to add it at the time of pulp exfoliation, since the crab light dye is well fixed to the pulp fibers. The prepared pulp slurry is dehydrated in a wire part to form a fiber arrangement, further dehydrated in a press part to a moisture content of 30 to 35%, and then transferred to a dry bart for drying.

In a general paper machine, there are about 20 to 60 dry barts in a cylinder dryer, and about 2/3 from the center.
A size press processing machine is installed at the location. This size press processing machine is a device that coats the surface of the base paper, and starch, polyvinyl alcohol, etc. are used here to increase the strength of the base paper and improve sizing properties. Finally, the surface properties are improved in a calendering process, and paper (transfer paper for electrophotography) is manufactured here. As described above, the transfer paper according to the present invention is one in which a specific fueigou dye (a bisaminostilbene sulfonic acid type fueigou dye represented by the above general formula) is present in the base paper. Preferred photo dyes are those in the above general formula in which M is Na salt, and more preferred photo dyes are 4,4-bis[2-(2,5-disulfoanilino)-4-phenoxy 1,3 - Sodium 5-triazinyl-6-amino]stilbene-2-di-disulfonate.

Example 1 LBKP beaten to 460cc with a deluxe finer
9 anchors and NBKPIO portion beaten to 200 cc using a double disc finer, refined to a total fineness of 430 cc in Jordan, and the resulting paper stock was mixed with 2.0% sizing agent and 3 sulfuric acid bands. .0%, polyacrylamide 7.0%, and clay 8.0% were added and paper was made at a papermaking speed of 400/min on a Saiami paper machine to obtain a base paper (transfer paper for electrophotography) - Invention Product 11. .

Note that this was carried out in the size press step in which the Rokuko dye was added. In addition, the size press liquid is starch (oxidized starch, MS
The amount of adhesion was determined by appropriately adjusting the liquid concentration and size press pressure. The size press liquid concentration in this Example 1 was 5%.
The amount of the crab light dye deposited is about 0.4 y/lb9 on the base paper, and the crab light dye has the above general formula where M is Na, X, and Y.
was hydrogen.

Example 2 An electrophotographic transfer paper (product of the present invention 2 ) was manufactured.

Example 3 Electrophotography was carried out in exactly the same manner as in Example 1, except that the size press liquid concentration was 5%, the amount of photoluminescent dye attached was about 0.50 Tano base paper lk9, and the photoluminescent dye was used. A transfer paper (invention product 3) was produced.

Comparative Example Electrophotography was carried out in exactly the same manner as in Example 1, except that the concentration of the 1-size press liquid was 5%, the amount of crab light dye deposited was 0.35 mm/base paper lk9, and the crab light dye was used. A transfer paper (comparative product 1) was manufactured.

Comparative Example 2 The concentration of the size press liquid was 5%, the adhesion amount of the crab light dye was 0.50 mm/base paper lk9, and then electrophotographic transfer was carried out in the same manner as in Example 1 except that the light dye was used. Paper (comparative product 2) was produced.

Comparative Example 3 The concentration of the size press liquid was 5%, the amount of crab light dye attached was 0.40Tano base paper lk9, and then electrophotographic transfer was carried out in exactly the same manner as in Example 1 except that the light dye was used. Paper (comparative product 3) was manufactured.

Comparative Example 4 Plain paper was produced in exactly the same manner as in Example 1, except that no honeydew dye was added (Comparative Product 4).
).

After evaluating these six types of samples, Table 1 below shows that
The measurement results shown in Table 2 were obtained.

As is clear from these results, the contrast of the product of the present invention is whiter, clearer, and better than the product without the addition of crab light dye (comparative product 4), and even with the occurrence of white spots in solid areas, It was confirmed that it was comparable to Comparative Product 4. In addition, for image production, DT-750 (electrophotographic copying machine, KK
(manufactured by Ricoh) was used. Table-1 (20℃, 60*RH environment) *1) Reflection density using Macbeth densitometer.

*2) Sensory evaluation: Rank 5 to IK, good to bad K, selected by panelists. *3) 30℃, 90%
After being exposed to RH for 2 minutes to adjust the humidity, white spots on solid areas were graded. As you go from rank 5 to rank 1, it goes from passing through to passing out. *4) Electrical resistance measuring device manufactured by Yokogawa Electric Hada (4329A HighResistanceM)
eter). Table 12 (under an environment of 30° C. and 90% RH) Note: The evaluation methods for image density, contrast hue, white spots, and volume resistance are the same as in Table 11.

Claims (1)

[Claims] 1 The following general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ may be the same group or different groups. M is a cation and represents hydrogen, an alkali metal or an alkaline earth metal. Transfer paper for electrophotography that is coated with an adhesive or size press.