JPS6334550A - Image forming method - Google Patents

Abstract

PURPOSE:To prevent generation of an image stain due to adhering to a toner by incorporating specific amounts of a styrene resin having an average weight mol.wt. of 0.5X10<4>-50X10<4>, a polyethylene wax grafted with a styrene monomer, and a low mol.wt. polyolefin to the toner. CONSTITUTION:The toner contains 100pts.wt. of the styrene resin having the mean weight mol.wt. of 0.5X10<4>-50X10<4>, 1-20pts.wt. of the polyethylene wax. grafted with the styrene monomer and 1-10pts.wt. of the low mol.wt. polyolefin. The styrene resin is exemplified by the polystyrene resin, the copolymer resin of the styrene or its derivatives and an another vinyl monomer. Said resin is used as the mixture of 1 kind or >=2 kinds of said resins. The average weight mol.wt. of said resin is 5,000-500,000, preferably, 10,000-300,000.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of converting an electrostatic charge image into a visible image and forming the image continuously on the front and back sides of transfer paper.

(Prior art) (Problems to be solved by the invention) Electrophotography,
There are two methods for developing electrostatically charged images in electrostatic recording images, electrostatic printing, etc.: one is a liquid development method that uses a developer in which various pigments and dyes are dispersed in an insulating organic liquid, and the other is a developer that uses a developer in which various pigments and dyes are dispersed in an insulating organic liquid. This method uses a developer consisting of a fine powder called toner in which a coloring agent is dispersed and a carrier such as iron powder or glass beads mixed therein.

The present invention relates to a method in which images are formed on both sides of a transfer paper by a magnetic brush method using a dry developer, or images are formed on one side of the transfer paper by composite copying.

In this case, composite copying is a method in which a copy is made on one side of transfer paper to form a fixed image, and then the original is changed and a copy is made again on the same side of the transfer paper to obtain a fixed image. It is used when it is desired to locally obtain a color image with color toner on a surface.

In a case where images are to be continuously formed on both sides or on one side of a transfer paper using conventional techniques, a transfer paper 1 is prepared with a toner image 2 transferred onto one side of the transfer paper as usual, as shown in Figure 1. A plurality of sheets of transfer paper 1 are placed on the paper feed table 3, and a paper feed rubber roller 4 is pressed from above and rotated in the direction of the arrow K, thereby sequentially sending out the transfer paper 1 in the direction of the arrow.

In this case, not only is the surface of the top transfer paper on the paper feed table 3 contaminated with roller dirt due to friction between the paper feed roller and the toner adhering surface, but also the surface of the plurality of transfer papers below it is stained. Also, due to the pressure from the paper feed row 4 and the weight K, the transfer paper becomes smeared due to friction between the toner adhesion surface and the transfer paper. The condition is as shown in FIG. 2, and the transfer paper IK having the toner image 2 has, for example, two parallel stripes of roller stain 5.

Further, when transferring and fixing the toner image 2B to the opposite side of the transfer paper 1 on which two toner images have been fixed on one side, for example, a fluororesin coat roller 6 is used on the upper part and a silicone resin coat is applied on the lower part, as shown in FIG. The image is heated and fixed by moving the transfer paper 1 in the direction of the arrow using the roller 7, but the disadvantage is that the two initially fixed images are transferred to the silicone-coated roller 7, causing roller stains on the transfer paper. was there.

As a countermeasure to this problem, it has been considered to provide a silicone oil supply section 8 above the fluororesin coating roller 6, as shown in the figure, to apply and fix silicone oil to the surface of the heat fixing roller.

That is, according to this method, a silicone resin film with releasable properties is formed on the surface of the toner image during the fixing of the first copy.
It exhibits mold releasability not only on the paper feed roller but also on the heat fixing roller.
Roller stains can be removed. However, in this case, it is necessary to install a silicone coating device, and this
Therefore, the configuration of the device is complicated, and the device is not cheap and compact, and its maintenance is also time-consuming.When the device is used for a long time, silicone oil accumulates on the paper feed roller, causing it to slip on the transfer paper. There were various problems such as paper feeding becoming impossible.

Also, instead of applying silicone oil, it is possible to mix low-molecular-weight oxidized polyethylene wax into the toner, but in this case, roller stains are less likely to occur, but the compatibility with the main resin is poor, and the copy image quality is reduced. There were problems such as deterioration of image quality.

(Means for Solving the Problems) The present invention has been made as a result of intensive research to solve these problems, and the outline thereof is as follows.

As a toner, the weight average molecular weight (hereinafter referred to as MW) is 0.5.
X 10' to 50 X 10' styrene resin 10
0 parts by weight, 1 to 20 parts by weight of styrenic monomer-grafted polyethylene wax, and 1 part by weight of low molecular weight polyolefin.
This is an image forming method characterized by using a toner containing up to 10 parts by weight, whereby an electrostatic latent image is developed on a photoreceptor by a magnetic brush method, and this toner image is transferred to a transfer paper, Even after repeating the heat roll fixing process twice, we were able to successfully obtain a clear image with no stains.

The constituent components of the toner used in the present invention are explained below.

Styrene resin polystyrene resin, styrene or its derivative <p-
'y lorsterene, vinyl toluenate) and other vinyl monomers (ethylene, vinyl chloride, butadiene, methyl acrylate, butyl methacrylate, acrylonitrile,
(acrylamide, N-vinylpyrrole, etc.), and one or a mixture of two or more of these may be used. Among these resins, those having a weight average molecular weight of ff1s, ooo~s, oo, ooo, and preferably an IQ of 000 to 300,000 are used in the present invention.

Examples of commercially available styrene-based resins include Sanyo Kasei Co., Ltd.'s "No-Imer-TB-1000J" product name and Gutdeyer Co., Ltd.'s "Prioride VTL" product name.

VTACL %ACL, ACJ, x Manufactured by Rough Chemical Co., Ltd. Product name "Picolastic D-150% D-125"
Examples include J.

Furthermore, even if the above-mentioned styrene resin has a MW of less than 5,000, the softening point is too low, so if it is used as a powder, the storage stability will be poor and the so-called blocking phenomenon will occur at room temperature, which is not preferable. . Also MW 50
If it exceeds 0,000, the softening point becomes too high, it becomes impossible to maintain constant low energy fixation, and the crushability is poor, so it is not preferable as a toner resin.

Styrene Monomer Grafted Polyethylene Wax> A known method can be used to graft the styrene monomer onto the polyethylene wax. For example, a method can be exemplified in which polyethylene wax is directly melted or dissolved in a solvent, and a styrene monomer is added with or without a radical initiator to graft the wax. As radical initiators, organic peroxides, organic bersesters such as benzoyl peroxide, dicumyl peroxide, di-tart-butyl peroxide, 2.5-
Dimethyl-2,5-di(peroxybenzoate)hexyne-3,1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, t
art-butyl peracetate, 2,5-dimethyl-2
,5-di(tart-butylperoxy)hexyne-3
, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylbenzony)
, tert-phthylberphenylacetate, tert
-butyl perisobutyrate, tsrt -butylperu aec-octoate, tert-butelperpiparate, cumylbelpino ζate and tert-butylbeldiethyl acetate, other azo compounds such as azobis-isobutylnitrile, dimethyl azoisoptate There is a rate. Among these, dicumyl peroxide, di-tθrt-butyl peroxide, 2,5-dimethyl-
2,5-di(tert-phthylberoxy)hexyne-
Dialkylbenzenes such as 3,2,5-dimethyl-2,5-di(tert-phthylberoxy)hexane and 1,4-bis(tert-butylperoxyisopropyl)hensen are preferred.

Low molecular weight polyolefin> Low molecular weight polyolefin is added to toner for hot roll fixing system, so MWloo・ooo
Hereinafter, preferably low molecular weight polyethylene or low molecular weight polypropylene of 20,000 to a,00 is preferred. Commercially available low molecular weight polyolefins include, for example, Allied Chemical's product name "AC Polyethylene 6A,"
617J, manufactured by Mitsubishi Kasei Corporation, product name “Viscol 550PJ”
etc., and one or a mixture of two or more of these may be used. The amount used is 1 to 10 fi parts, preferably 3 to 5 parts, from the viewpoint of imparting mold release properties and improving fluidity! ! Select within the range of quantity. If it is less than 1 part by weight, the mold releasability will be insufficient and the fluidity will not improve much, and if it exceeds 10 parts by weight, the dispersibility in the main resin will be poor, resulting in poor image quality.

Note that even if a polyolefin having a MWjQ of more than 000 is used, the offset phenomenon cannot be prevented because of its high softening point.

(Example) Example 1: Styrene-acrylic copolymer resin (manufactured by Sanyo Chemical Co., Ltd. "Himer TB-100DJ MW = 35 x 104
) 92 parts by weight, styrenic monomer-grafted polyethylene wax (“Hiwax 2” manufactured by Mikata Petrochemical Industry Co., Ltd.)
235H), 2 parts by weight of low molecular weight polypropylene ("Viscol 5oopJ" manufactured by Sanyo Chemical Co., Ltd.), and 7 parts by weight of carbon black ("Mitsubishi Carbon $4oJ" manufactured by Mitsubishi Kasei Corporation) were melted and kneaded using an extruder, then extruded using a jet mill. A toner with an average particle size of 11 μm was obtained by finely pulverizing the toner with an iron powder carrier (Kanto Denka Co., Ltd. 25).
0/400 mesh type “TK-857LJ) 1
00 parts by weight to prepare a developer.

This developer was applied to a double-sided copying machine having 58 photoreceptors, and 50,000 continuous copies were made on both sides of transfer paper. The result is the beginning of the copy and so, o o.

Image density after double-sided copying (Macbeth reflection density)
were 1.5 to 1.4 and 1.2 to 1.3, respectively, and a sufficient density was obtained, and a clear image without capri was obtained.

Further, even after copying 5Q, 000 sheets, a good image was maintained with no paper feed roller stains or fixing roller stains.

Example 2 Nis-tren-acrylic copolymer resin "Prioride ACJMW=150.0" manufactured by Gutdeyer Co., Ltd.
A developer was prepared in the same manner as in Example 1 except that 00 was used.

In this case as well, the same copying machine as in Example 1 was used to print s o, o.
When I made double-sided copies of o sheets, the image density was 1.
．． 2 to 1.3, a good image without capri was obtained, and there was no occurrence of roller stains.

Comparative example: A toner made under the same conditions as in Example 1 was used, except that oxidized polyethylene (Hiwax 2205AJ, manufactured by Mikata Petrochemicals) was blended in place of the styrene thread-grafted polyethylene wax in Example 1. o o
Double-sided copying of o sheets was performed. At that time, no roller dirt occurred, but the image was defective (clear image could not be obtained)
I woke up.

(Effects of the Invention) When the method of the present invention is used, clear images can be formed on both sides of transfer paper at high speed without causing image stains due to toner adhesion to the paper feed roller and heat fixing roller.

[Brief explanation of the drawing]

Figure g1 is a partial vertical sectional view showing the relationship between the serving table, transfer paper, and serving rubber roller, Figure 2 is a front view showing the state of dirt on the transfer paper, and Figure 3 is a partial longitudinal sectional view showing the relationship between the serving table, transfer paper, and serving rubber roller. Side view when fixing with heat 1: Transfer paper 2: Toner fixed image 3: Paper feed stand 4: Rubber roller 5: Bleeding 6: Fluorine resin roller 7: Silicone resin roller 8: Silicone oil coating layer

Claims (1)

[Claims] The electrostatic latent image on the photoconductor is developed using an electrostatic charge image developing toner using a magnetic brush method, the resulting toner image is transferred to transfer paper, and the process of fixing the toner image with a hot roll is repeated twice. In an image forming method in which images are formed on both sides of the transfer paper or images are formed on one side of the transfer paper by composite copying, the toner has a weight average molecular weight of 0.5 x 10^4.
100 parts by weight of ~50 x 10^4 styrene resin and 1 to 2 parts of styrenic monomer-grafted polyethylene wax
0 parts by weight, and 1 to 10 parts by weight of a low molecular weight polyolefin.