JPS6362739B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an improvement in a powder development toner suitable for flash fixing in electrophotography.

(2) Background of the Technology The present inventors have already proposed a powder developing toner suitable for flash fixing in Japanese Patent Application Laid-Open No. 56-30139 and Japanese Patent Application No. 55-171970. That is, in electrophotography such as printers, facsimiles, and copiers, images developed with toner are usually fixed using a heat roll or heat oven, but when such toner is fixed by flash, low molecular weight substances are decomposes, emitting a foul odor and emitting gases that are harmful to the human body. Therefore, the toner for flash fixing (Japanese Patent Application Laid-open No. 30139/1983) generates only a small amount of gaseous low-molecular-weight substances that give off a bad odor during flash fixing. (Japanese Patent Application No. 171970).

When copying is performed using this toner, blocking of toners among themselves is prevented as described above, but toner adhesion (toner filming) to the carrier surface and the surface of the photoreceptor drum on which the latent image is formed is relatively low. This problem occurs quickly and tends to cause a decrease in image contrast, background fog, and poor toner image transfer.

(4) Purpose of the Invention An object of the present invention is to provide a toner for electrophotographic flash fixing that eliminates the above-mentioned drawbacks, prevents deterioration in copy image quality, and significantly improves the life of the carrier and photosensitive drum. .

(5) Structure and object of the invention According to the invention, 0.6 to 8% by weight of carbon, 0 to 8% by weight, based on the weight of toner particles.
5% by weight dye as colorant, 86-99.4% by weight
A toner for electrophotographic flash fixing comprising a binder resin of
This is achieved by providing an electrophotographic flash fixing toner comprising a bisphenol A/epichlorohydrin type epoxy resin at 160°C, an epoxy equivalent of 450 to 5500, a weight average molecular weight of 900 to 8250, and a degree of polymerization of 0. .

(6) Embodiments of the invention Proposed as a toner for a flash fixing method in which a toner image is irradiated with high-energy ultraviolet rays, visible light, and infrared rays to instantaneously raise the temperature of the toner to the melting temperature of the toner and fix the toner image. Special request 1977-
In No. 171970, the amount of montanic acid ester wax added was 1 to 20% by weight. In the present invention, more detailed studies were conducted to prevent the occurrence of toner filming. In other words, when the montanic acid ester wax is 1 to 5% by weight, toner tends to adhere to the surface of the photoreceptor drum, and when it is 5 to 20% by weight, the wax contained in the toner oozes out, causing wax to adhere to the surface of the photoreceptor drum. Adhesion (toner filming) occurs, and after 10,000 to 30,000 sheets have been printed, copy quality deteriorates, that is, image contrast decreases, background fogging, and toner image transfer failure occur.

These reductions in copy quality depend on the proportion of bisphenol A glycidyl ether with a degree of polymerization (n) of 0 contained in the epoxy resin rather than on the average molecular weight of the binder resin. i.e. n
=0 bisphenol A glycidyl ether is 4
Toner filming is 60000 when it exceeds weight%
This occurs after ~10,000 sheets have been printed, and filming on the carrier surface increases and a rapid decrease in the amount of charge is observed.

In order to prevent this, in the present invention, the amount of n=0 bisphenol A glycidyl ether contained in the epoxy resin is set to 4% by weight or less.
The addition amount of the montanic acid ester wax is 1% by weight or less, which is the minimum amount to prevent blocking between toner particles, and it is possible to obtain a toner for flash fixing that has a remarkable effect on the occurrence of toner filming.

Example 1 Bisphenol A/epichlorohydrin type epoxy resin containing about 3.0% by weight of bisphenol A glycidyl ether with an epoxy equivalent of about 950, a weight average molecular weight of about 1400, a melting point of about 100°C and a degree of polymerization n=0.
92.5% by weight, 5% by weight of carbon black fine powder (Black Pearls, manufactured by Kayabot Corporation), 2% by weight of Nigrosine-based dye (Nigrosine Black EX, manufactured by Orient Chemical Industry Co., Ltd.), and montanic acid ester wax (Ester Wax E, (manufactured by Hoechst) was kneaded in a kneader heated to 100°C. The molecular weight distribution of the epoxy resin used was n = 0 from the liquid chromatography chart.
The weight percentage of bisphenol A glycidyl ether was determined by calculating the proportion occupied by the peak.

Next, the kneaded product was pulverized using a jet bulbilizer, and then classified using an air classifier to obtain a toner. A printing test was conducted using the obtained toner using an F6700 laser printer (manufactured by Fujitsu). That is, the latent image was fixed by exposing it to flash light of 300 J/pulse from a xenon flash lamp. As a result, even when 200,000 copies of character prints are produced, the printed character images remain clear.
No fog formation was observed in the background area, and no toner filming occurred on the photosensitive drum.

Comparative Example Bisphenol A glycidyl ether with n=0 used in the above example is replaced with 3.0% by weight of epoxy resin.The epoxy equivalent, weight average molecular weight and melting point are the same, but bisphenol A glycidyl ether with n=0 is used instead of 3.0% by weight of epoxy resin. The composition was 90% by weight of epoxy resin with 4.9% by weight, carbon black fine powder (5% by weight), nigrosine base dye (2% by weight), and montanic acid ester wax (3% by weight) as in the example. The toner was prepared in the same manner as in the example, and a printing test was performed using a laser printer. As a result, after 20,000 copies were made, toner drum filming occurred, character images became unclear, and fog formation was observed in the background. Even in the case of the toner in which the wax content was increased to 10% by weight, a wax film was formed on the drum surface due to wax seepage after about 30,000 sheets, and the transferred image became unclear. When the wax content was less than 1% by weight, toner filming was likely to occur and the drum life was less than 10,000 sheets.

Example 2 Epoxy resin (EPOXY-A) with n=0 component 3.0% by weight used in Example 1 and n=0 used in Comparative Example
Epoxy resin with 0 component 4.9% by weight (EPOXY-B)
FIG. 1 shows toner compositions in which the amount of wax added as a base resin was varied.

For each toner produced in the same manner as in Example 1, tablets for evaluating filming properties were prepared. Filming properties were evaluated by bringing a tablet-shaped sample of powdered toner proposed in Japanese Patent Application No. 56-065515 into contact with a glass plate under a constant load, and forcing friction until the toner adhered to the surface of the glass plate. A filming tester was used to evaluate the number of times of sliding. The results are shown in FIG. With the same amount of wax added, there are fewer n=0 components
EPOXY-A toner is less prone to filming. In other words, by reducing the n=0 component, the filming resistance is significantly improved even with the addition of a small amount of wax, and compared to the number of sliding cycles before filming occurs with EPOXY-B toner without wax addition, it takes 10 times. EPOXY-A toner has improved filming resistance by 1.7 times to 17 times, and when the amount of wax added is 1% by weight, filming resistance has improved by 2.7 times to 27 times for A toner compared to 10 times for B toner. are doing. The amount of wax added is 1% by weight.
If this is done, a wax film will be formed on the drum, which is undesirable.

(7) Effects of the Invention The flash fixing toner of the present invention can suppress the generation of bad odors and harmful gases that can cause problems during fixing.
This prevents blocking, where toner particles aggregate, and prevents toner filming on the surface of the photoreceptor drum, making it possible to improve the number of continuous copies by about 10 times compared to conventional methods.

[Brief explanation of drawings]

FIG. 1 shows the composition of various toners used to explain Example 2, and FIG. 2 shows the relationship between the amount of wax added and the number of times of sliding until filming occurs.

Claims (1)

[Claims] 1 Based on the toner particle weight, 0.6-8% by weight of carbon, 0-5% by weight of dye as colorant,
Melting point 60-160℃, epoxy equivalent of 86-99.4% by weight
450-5500, weight average molecular weight 900-8250, and degree of polymerization 0/bisphenol A/with glycidyl ether content less than 4% by weight.
A toner for electrophotographic flash fixing comprising an epichlorohydrin type epoxy resin and less than 1% by weight of a montanic acid ester wax.