JPH0713753B2 - Pressure fixing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic method, an electrostatic recording method, a magnetic recording method, or
The present invention relates to a toner used in an electrostatic printing method or the like, and particularly to a toner suitable for pressure fixing.

As the conventional electrophotographic method, many methods are known as described in U.S. Pat.No. 2,297,691, Japanese Patent Publication No. 42-23910, etc., but generally, a photoconductive material using a photoconductive substance is used. An electrical latent image is formed on the body by various means, then the latent image is developed with a toner, and the toner image is transferred to a transfer material such as paper, if necessary, and then a solvent, heat,
It is fixed by pressure to obtain a copy.

As a fixing method using a solvent, a method of removing the solvent after dissolving and adhering the toner, and a method of applying and fixing a resin solution called a fixing solution on the image are known. There are many items that are not suitable for use as an office machine, such as the effect of, the problem of wetting of the copy, and the time required for drying.

The fixing method using heat is the mainstream at present, and there are a method of melting and adhering the toner with a heat chamber, a method of melting the toner with a heat roller and at the same time filling the toner. However, in the fixing method using this heat, it is necessary to regulate the transfer material and the toner image so as not to cause deterioration such as deterioration or fire while maintaining a sufficient amount of heat for melting the toner. And control are likely to be complicated. In addition, the ratio of the toner image on the transfer material is usually extremely small, and since heat conduction to the transfer material and heat dissipation to the periphery of the fixing device occur, the amount of heat consumed relative to the amount of heat actually required for fixing is increased. Is extremely inefficient. In the case of a copying machine, most of the electric capacity is used for fixing, and fixing always determines the ability of the copying machine. In order to speed up the start-up of the fixing device and increase the fixing speed, fixing is necessary. It is necessary to devise to reduce the heat capacity of the part related to Also,
The effect of air humidity cannot be seen, and the lower the air humidity and the higher the humidity, the more heat is required.

On the other hand, the fixing method using pressure is to adhere the toner to the fluidized transfer material by pressure instead of heat, and pressure is static energy unlike heat and force It is only related to the action surface of and is not influenced by other external environment. As a general pressure fixing method, pressure is applied to both ends, and a member to be fixed is passed between a plurality of rolls intersecting each other. The fixing is performed almost immediately after passing through the pressure unit, and the energy required to rotate the pressure roll required for the fixing is smaller than the energy required for the thermal fixing device. The characteristic of this pressure fixing is a great advantage in terms of high-speed fixing, online / real-time fixing, and simplification of the fixing mechanism.

However, while the conventionally known pressure fixing method has the above-mentioned great merits, there are some serious drawbacks that cannot be the mainstream of the fixing method at present.

One of them is that the pressure required for fixing is generally 20 to 40 kg / cm, but in order to apply such a force, the strength of the fixing device is required to be quite strong, and the fixing device becomes large and heavy. That is, it is not preferable, and the fixing device is easy to work. In addition, the other is that it is essentially extremely difficult to apply the above pressure evenly to an image such as a transfer paper, and the transfer paper is wrinkled, the surface becomes glossy, and further it becomes transparent. It is extremely difficult to prevent such accidents. Further, the other decisive one is that the durability and stability as a toner are not enough.

When the fixing pressure becomes less than 5 kg / cm in A-4 width, there is a great merit in reducing the load on the bearing that supports the pressure roll, but even at higher pressure, the device is lightweight. There is a great deal of merits to change to Also, the linear pressure is 15 kg / c
Below m, transfer paper can be expected to have gloss and curl. When the linear pressure is 15 kg / cm or less, the fibers of the paper will not be crushed, but in this case, it is expected that the toner particles trapped between the fibers will receive the pressure necessary for fixing. become unable. In order to ensure the unevenness of the paper, it is effective to make the pressure / bottoming roll elastic, but since the area of the contact surface where pressure is applied expands, the pressure applied to the toner does not increase even with the same linear pressure. It becomes smaller and the toner is required to collapse at a lower pressure. As a substance that fixes at such a low pressure,
Long-chain compounds having a carbon chain of about C _{12 to} C _50- hydrocarbons, fatty acids, esters thereof, metal soaps, fatty alcohols, polyhydric alcohols, and metal salts thereof, chlorides thereof, fluorides, amides, bisamides and so on. However, because of the nature of these substances, the dispersion of dyes and pigments is extremely poor, and due to their softness, they are toner particles of a certain fixed particle size, and they have the stability and durability required for toners. It is difficult to maintain the property that it is present or developable. For this reason, mixing with other hard resins is carried out, but the above substances have extremely poor compatibility, and even if they are dispersed, they are liberated on the surface due to aging, so that the developability and durability are adversely affected. Will be given. Specifically, the developer carrier, the stain of the low-pressure fixing material on the developing sleeve, the aggregation of toner, the toner offset on the pressure roll of the fixing device, and the contamination on the surface of the photoconductor are notable. is there. Although it certainly adheres to the transfer paper at a low pressure, the image surface is sticky and spreads around when it is rubbed to smear the copies or leave a large number of copies stacked for a long time. If it is left, it is difficult to say that it has settled in, such as causing a set-off phenomenon.

An object of the present invention is to provide a pressure fixing toner which is excellent in developability, durability and stability and can be fixed at a low pressure.

Another object is to provide a pressure-fixing toner that does not cause fusion on the toner contact surface such as the photosensitive surface, developer carrier, developing sleeve, fixing pressure roll surface.

Still another object is to provide a pressure-fixing toner having good fixability.

Specifically, the present invention has a molecular weight of 10,000 to 10 having the following repeating unit (I).
Pressure-fixing toner containing 40 to 90 parts by weight of a ring-opening polymer of ε-caprolactone per 100 parts by weight of a binder resin. Regarding

The ring-opening polymer of ε-caprolactone is a crystalline polymer having the following repeating unit (I): It has good compatibility with various resins, especially polyolefin, and when added to various resins, it imparts plasticity and shows good adhesion to various materials. It also has excellent dispersibility for inorganic and organic pigments.

Usually, several hundreds of paraffins that can be pressure-fixed at an extremely low pressure, even polyethylene, which is a hard pressure-fixing substance, has a number average molecular weight of the order of several thousand, but is used in the present invention. The ring-opening weight part of caprolactone is
Even with a molecular weight of 10,000 to 100,000, it has a pressure fixing property comparable to that of paraffin type. Further, in the fixing, in the case of a low-pressure fixing toner containing paraffin, when the fixed image is repeatedly rubbed, the toner spreads and stains on a white background around the fixed image, whereas the ring-opening weight part of ε-caprolactone is stained. Has very little growth. The offset of the toner to the pressure fixing roll is considerably large in the case of the low pressure fixing toner containing paraffin, and is not a little observed in the polyethylene type toner, but it is very small in the case of ε-caprolactone. Further, in the case of a paraffin-based toner, when left at a high temperature, the paraffin component undergoes phase separation and is released to the surface, so that the developability deteriorates and, in the case of a fixed image, it also causes set-off. . Such a phenomenon is not limited to paraffins, and is often seen in other waxes, metal soaps, and the like having a low molecular weight. On the other hand, in the case of the ring-opening polymer of ε-caprolactone, the above-mentioned phenomenon is not observed despite the low softening point of 60 ° C.

Since the weight part of ε-caprolactone itself lacks in rigidity, it is difficult to handle when granulating and operating as toner particles by itself, and it is preferable to use it in combination with other hard particles. As the resin used in combination, known resins such as polyester resin, epoxy resin, silicone resin, polystyrene resin, acrylic resin, polyamide resin, and polyurethane resin can be widely used,
High-density polyethylene is preferably used because of its pressure-fixing property and after fixing, it imparts lubricity to the fixed image surface and resistance to rubbing.

The compounding ratio of the ring-opening polymer of ε-caprolactone in the binder resin of the pressure-fixing toner is 40 per 100 parts by weight of the binder resin.
To 90 parts by weight. When the other polymer is polyethylene, even if 60 parts by weight of polyethylene is added, the fixing pressure does not increase so much and the fixing can be performed at a pressure of about 15 kg / cm or less, and as shown in Example 3 described later, ε- Even if 90 parts by weight of the ring-opening polymer of caprolactone is blended, a good pressure-fixing toner can be prepared.

In addition to mixing, the resin may be a so-called microcapsule type toner having ε-caprolactone as a core material and a resin coating around the core material.

Further, the pressure-fixing toner of the present invention may contain various dyes and pigments and magnetic powder.

Further, the pressure-fixing toner of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder, and ferrite powder, if necessary, and used as a developer for an electric latent image.

Further, for the purpose of improving the free flowing property of the powder, it may be used by mixing with hydrophobic colloidal silica fine powder, abrasive fine particles such as cerium oxide for preventing toner sticking, and a lubricant such as stearate. it can.

The present invention will be described in detail with reference to examples.

Example 1 Polyethylene Hiwax 400P (Mitsui Petrochemical, density 0.97 g / cm ³ ) 4
0 parts by weight Poly-ε-caprolactone (trade name: PLACCEL H-1 manufactured by Daicel Chemical Industries, Mn = about 10,000) 60 parts by weight Magnetite 80 parts by weight The above materials were well mixed by a blender and then melt-kneaded at 150 ° C.

The kneaded product was allowed to cool naturally, then roughly crushed with a carter mill and then finely crushed with a jet mill. The finely pulverized product was further classified using an air classifier to obtain a toner of 5 to 20 μm. Hydrophobic colloidal silica (trade name: R-972,
0.3% by weight of Nippon Aerosil Co., Ltd. was externally added, and a transfer image was obtained by an electronic copying machine (trade name: NP-120, manufactured by Canon Inc.). The transfer paper with this image is composed of two pressure rolls that can be pressed from both ends.
After passing through a pressure fixing device using a 3 mm polyurethane roll, it showed almost perfect fixing property at a line pressure of 12 kg / cm at a speed of 125 mm / sec. The fixed image was vivid, had no fog, did not come off even with strong rubbing, and did not stain the surrounding white background. Also, fold the image,
Even if the folds were rubbed, the images did not drop out. This fixed image was applied to a blank sheet of the image, and was left at 40 ° C. for 1 week so that a weight of 4 kg was uniformly applied to the entire surface of the A-4 paper, but no transfer of the fixed image was observed.

Using this toner, continuous copying was further performed on 10,000 sheets, but the image density decreased, toner caking in the developing unit,
No fusion of toner to the sleeve or the photosensitive drum was observed.

When this toner was left at 50 ° C. for one week, there was no blocking of the toner and no change in developability.

Comparative Example 1 100 parts by weight of Hiwax Magnet 80 parts by weight of magnetite The above mixture was pulverized in the same manner as in Example 1 to obtain a toner. Image formation was carried out in the same manner as in Example 1 to check the fixing property. When the image fixed with a pressure of 35 kg / cm was folded, not only the creases but also the toner around them were partially dropped.

[Comparative Example 2] Paraffin (155 ° C) was used instead of poly-ε-caprolactone.
Example 1 was repeated except that F) was used. When the fixed image passed through a 12 kg / cm pressure roll was rubbed, the image spread and spread around the image, contaminating the white background. Also, apply this fixed image to the image with a blank sheet and
-4 Apply 4kg of load evenly over the entire surface of the paper, and
When left at 0 ° C. for one week, the paper adhered and when peeled off, 1 part of toner peeled off. Also, when left at 50 ° C for one week, the toner blocks and unravels again,
It did not show sufficient developability.

When continuous copying was performed using this toner, the developing property was significantly deteriorated after about 100 sheets, and the toner in the developing device was strongly aggregated and solidified. At this time, fusion of the toner was observed on the film on the photoconductor.

Further, this toner has a strong toner offset to the fixing roll, and even when a release agent such as silicone oil is used, offset of the toner to the fixing roll and re-offset from the roll to the transfer paper were observed.

[Example 2] Polystyrene (Brand name: Picolastik D-125, manufactured by Herki Yulesnee) 30 parts by weight Poly-ε-caprolactone (Brand name: Praxel H-4,
Daikin Chemical Industry, Mn = about 40-60,000) 70 parts by weight Magnetite 80 parts by weight The above materials are dissolved in 1000 parts by weight of toluene, sprayed and dried by a spray dryer, and then classified by a wind classifier, 20 μ of toner was obtained. 0.3% by weight of hydrophobic colloidal silica was externally added to this toner, and the same procedure as in Example 1 was performed.

The transferred image was fixed at a linear pressure of 15 kg / cm. The toner exhibited the same developability and stability as the toner of Example 1. This toner was superior in fluidity to the toner of Example 1.

[Example 3] Polyethylene (trade name: 130, manufactured by Hoechst, density 0.96 g / c
m ³ ) 10 parts by weight Poly-ε-caprolactone (trade name: Praxel H-
1) 90 parts by weight Phthalocyanine blue 5 parts by weight The above materials were thoroughly mixed with a blender, dissolved at 130 ° C, and sprayed with compressed air at 200 ° C from a two-fluid nozzle to collect fine particles. Then, using an air classifier, particles of 5 to 20 μm were obtained. This classified particles 100
20 parts by weight of a styrene-dimethylaminoethyl methacrylate (9: 1) copolymer was dissolved. Disperse in 1000 weight of MIBK, add methyl alcohol under stirring, phase-separate the styrene-dimethylmethacrylate copolymer, and add the core substance consisting of polyethylene and poly-ε-caprolactone to the styrene-dimethylaminomethacrylate copolymer. A polymer coated toner was obtained. This toner 50
gr, mixed with 300 gr ferrite particles 300 ~ 30μ particle size,
An alternating electric field by contacting a developing device having a 30φ sleeve with an alternating magnetic field inside and a doctor blade with the gap between the sleeve and the sleeve adjusted to 150μ with a photoconductor having a negative charge latent image at a gap of 350μ. Was applied between the photosensitive member and the sleeve to develop. The image obtained was clear and free from fog. The fixing pressure was 10 kg / cm. While the toner was replenished with this developing device, an image was further printed on 5,000 sheets, but there was no deterioration of the image and no fusion of the toner onto the photosensitive drum was observed.

Furthermore, even if this developer was left at 50 ° C. for one month, no change was observed in the developability.

[Comparative Example 3] The procedure of Example 3 was repeated except that caster wax was used instead of poly-ε-caprolactone. At the initial stage of continuous image formation, an image which is the same as that of the developer of Example 3 was obtained, but after about 1000 sheets, the toner and the ferrite carrier particles began to separate, and the image became thin and fogging was conspicuous. It became. At this time, a toner fusion phenomenon was observed on the photosensitive drum. When the fresh developer was left at 50 ° C for one month, a separation phenomenon between the toner and the developer was observed, and even when re-mixed, it did not mix.

Front Page Continuation (72) Inventor Satoshi Wakamiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshiaki Nakahara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naoyuki Ushiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-59-135478 (JP, A)

Claims (1)

[Claims] 1. A ring-opening polymer of ε-caprolactone having a repeating unit of the following (I) and having a molecular weight of 10,000 to 100,000 is contained in an amount of 40 to 90 parts by weight per 100 parts by weight of a binder resin. Pressure fixing toner.