JPS59162561A - Transfer paper for electrophotography - Google Patents

Abstract

PURPOSE:To improve copy quality by incorporating a specific amount of ash contents in transfer paper which is used for the electrophotography of a positive- polarity tower development system. CONSTITUTION:The transfer paper used for the electrophotography of the positive-polarity toner development system contains <=4wt% ash contents. Thus, the ash contents are specified to prevent the formation of a flocculate of paper powder and toner and the opposite-polarity electrostatically charge of the toner resulting from the negative charge of paper powder components in the transfer paper, specially, a filler in the paper due to friction, contacting, separation, etc., as to the toner or carrier. Consequently, a copy of high quality free of the fogging of the background and fine absence of a copy image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transfer paper used in electrophotography, particularly in electrophotography using a positive polarity toner development method.

Conventional technology Electrophotography using a positive polarity toner development method uses a two-layer photoreceptor (
A method of forming a negative electrostatic latent image using a functionally separated photoreceptor), a polyvinyl carbazole organic photoreceptor, a zinc oxide photoreceptor, a cadmium sulfide photoreceptor, etc., a method of forming a positive electrostatic latent image using a Se-based photoreceptor, etc. There is a method of forming an electrostatic latent image and performing reversal development.

When conventional electrophotographic transfer paper using a negative toner development method is used in such an electrophotographic copying machine using a positive toner development method, paper dust adhering to the photoconductor may not be sufficiently cleaned during the toner image transfer process. When cleaning toner is reused, paper dust gets mixed into the developer, causing background fog and the like, resulting in poor copy quality.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a transfer paper for electrophotography, particularly of a normal toner development system, which can eliminate the drawbacks of the conventional transfer paper and provide good copy quality.

Structure of the Invention In general, the main characteristics required of electrophotographic transfer paper are copy quality and runnability (no paper jams, single double feed, etc.).

It has transferability, fixability, etc.

In the conventional electrophotographic method using negative polarity toner development method,
Various measures have been taken for transfer paper to improve copy quality.

For example, to maintain an appropriate copy image density and prevent background (blank paper) stains.

The surface electrical resistance of the transfer paper (
JIS C-2111) to io'~1010Ω(
The humidity (R, H,) is 65 degrees, and the temperature is 20 degrees Celsius. Furthermore, in order to improve the sharpness of the copy image area, surface irregularities are reduced and the smoothness of the transfer paper (according to JIS P-8119) is set to 20 seconds or more. Furthermore, if the transfer paper partially absorbs moisture and swells or curls, the closeness between the photoreceptor of the copying machine and the transfer paper decreases during transfer, resulting in a decrease in copy image density and partial omission of copies. To prevent this, the water content of the paper is set to 4.5 to 5.5 inches, and the paper is wrapped in moisture-proof wrapping paper to prevent moisture absorption and desorption during storage.

That is, in the case of conventional electrophotographic paper using a negative polarity toner development method, various measures as described above are taken in order to obtain satisfactory copies.

However, in electrophotography using positive polarity toner development method,
If paper manufactured by Fuji Xerox Co., Ltd. or other PPC paper for which the above-mentioned measures have been taken are used, the background will become smudged and fine white spots will appear in the copied image area, making it impossible to obtain satisfactory copies.

The present inventors investigated the cause of this through various experiments, and found that the paper dust components of conventional electrophotographic transfer paper, especially the filler in the paper, caused friction with the toner or carrier.

It was discovered that this is because aggregates of paper powder and toner are formed due to negative band 'IL due to contact and separation, and toner of opposite polarity increases, and based on this knowledge, the present invention was completed. did.

In other words, with conventional transfer paper, paper dust generated from the surface and cut surface of the transfer paper that adheres to the photoreceptor during the toner image transfer process, mainly filler powder such as talc and kaolin, and some fine fibers, The toner may not be cleaned or may be mixed into the developer by reusing toner after cleaning. These mixed materials become negatively charged due to friction, contact, and separation with the toner and carrier.
Aggregates with toner of positive polarity (generally have weak opposite polarity)
or increase reverse polarity toner, causing background smudges and small gaps in copied images. It was also found that fillers such as talc and kaolin have the greatest effect among paper powders. FIG. 1 shows the relationship between the contents of talc and kaolin in transfer paper and copy quality. Figure 1 shows 1 tsubo weight 649/yr? The ratio of filler was varied in the transfer paper, and copies were made using a copying machine using a positive polarity toner development system, and the copy quality after 10,000 copies was plotted against the ratio of filler. In the figure, A on the vertical axis indicates a state in which there are no background stains and small omissions in the copied image, B indicates a state in which there are some background stains and/or small omissions in the copied image, but there is no practical problem. C means that the background is dirty and/or the copied image has some small omissions (but it can be used depending on the purpose); D means that the background is dirty and/or the copied image has many small omissions and cannot be used. .

From the results shown in FIG. 1, it is clear that when talc and kaolin are used as fillers, the copy quality is good if the content is 4 to 5% by weight or less. A similar tendency is observed for the level of copy quality with other fillers, and the copy quality varies slightly depending on the type of filler, but in any case, the typical basis weight is 64f/rr? It has become clear that copy quality with no practical problems can be obtained with transfer paper having an ash content of 4% by weight or less according to JISP-8128. However, the high-quality paper including electronic copying machine paper and printing paper currently used in electronic copying machines is talc 1 and clay.

Fillers such as calcium carbonate are added at 6% by weight or more, and the ash content of these papers is also at least 5.5% by weight, so there is no paper that can be satisfactorily used for electrophotography using positive polarity toner development. There wasn't.

That is, 1 the present invention has an ash content of 4 according to JISP-8128.
By using electrophotographic transfer paper using a positive polarity toner development method, the defects of conventional transfer paper can be eliminated and good copy quality can be obtained. In addition, the ash content is 4
By weight% or less, the properties required for electrophotographic transfer paper other than copy quality are almost the same as paper for electrophotographic copying machines using the conventional negative polarity toner development method (it has been confirmed that there are no problems in practical use). has been done.

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

Examples 1 to 5 and Comparative Examples 1 to 3 L-BKP (hardwood bleached kraft pulp, freeness 450CC), N-BKP at the blending ratios shown in Table 1.
(Softwood bleached kraft pulp, freeness 480CC)
and GP (kraft pulp, freeness 65 CC) and filler on a Fourdrinier paper machine for 430-450 m.
5 types of paper (Examples 1 to 5) were made at a paper speed of /”,
Oxidized starch LfIn as a surface sizing agent? and 0.1f/nl of sodium chloride were applied and cut using a LENOX automatic cutting machine. The ash content of the transfer paper made in this way according to JISP-8128l is measured,
Paper quality (1 tsubo weight.

Table 1 shows the smoothness of both sides and the copy quality after copying 10,000 copies using a positive toner development type copying machine. In addition, as a comparative example, three commercially available papers (PPC paper from Company B, high-quality paper from Company B,
C? Table 1 also shows the results of similar measurements performed on 1mPPC medium-quality paper.

Effects of the Invention As described above, the electrophotographic transfer paper using the positive toner development method of the present invention has an ash content of 4% by weight or less, and this transfer paper reduces background fog and A high-quality copy can be obtained without causing small omissions in the copied image.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the filler content in the transfer paper and the copy quality after copying the 10,000th copy using a positive polarity toner development type copying machine. Fig. 1 Transcription of moth trends (medium weight 2)

Claims (1)

[Claims] An electrophotographic transfer paper for positive polarity toner development, characterized in that its ash content (according to JISP-8128) is 4% by weight or less.