JP2001013712A - Nonmagnetic one-component toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce rotational torque of a developing roller and a photoreceptor or the like, to prevent ununiform rotation and to prevent the occurrence of a jitter image by sticking fine fluororesin powder, silicone oil treated fine silica powder and fine alumina powder to the surface of a toner. SOLUTION: Fine fluororesin powder, silicone oil treated fine silica powder and fine alumina powder are stuck to the surface of a toner to obtain the objective nonmagnetic one-component toner. The used silica has a polydimethylsiloxane group or the like on the surface by silicone oil treatment. The particle diameter of the silica is preferably 0.008-0.02 μm. The fluidity of the toner is improved, an amount of the toner supplied to a developing roller is increased and sufficiently high image density is obtained without causing surface fogging. The amount of the treated silica is preferably 0.8-1.6 pts.wt., particularly preferably 1.0-1.4 pt.wt. based on 100 pts.wt. toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a one-component developing apparatus having a toner layer thickness regulating blade in a copying machine, a printer or the like, and more particularly, to a toner fusion to a toner layer thickness regulating blade. By preventing toner filming on the photosensitive drum and reducing the driving torque of the developing roller, images such as jitter images (horizontal stripes corresponding to the number of gear teeth for driving the developing roller), image white streaks, and background fogging are obtained. The present invention relates to a non-magnetic one-component toner capable of maintaining good development characteristics even after repeated use without causing a problem.

[0002]

2. Description of the Related Art In recent years, a copying machine or a printer has been required to have a function as an image output device from a computer in addition to a normal copying function, and has specifications such as space saving, energy saving, light weight, colorization, and simple configuration. For this reason, non-magnetic one-component development has been used. Since non-magnetic one-component development does not use a magnetic carrier unlike two-component development, a developing roller and, in order to give a triboelectric charge to the toner and form a magnetic brush having a uniform thickness,
At least a toner layer thickness regulating blade which has elasticity and is in contact with the developing roller is required. The non-magnetic one-component toner obtains a triboelectric charge by friction with the developing roller and the regulating blade, and the thickness of the layer is regulated by the regulating blade. Usually, hydrophobic silica fine powder is dispersed and attached to the surface of the toner in order to improve fluidity and chargeability. However, in one-component development, stress is applied particularly between the layer thickness regulating blade and the developing roller, so that toner aggregates adhere and grow on the toner surface side of the blade due to repeated use for a long period of time, and the aggregates become toner. In order to prevent the formation of a thin layer, the toner layer is not formed in a streak shape on the developing roller from the agglomerate as a starting point, resulting in image white streaks. Further, there is a problem that the rotation torque to the developing roller increases due to the contact of the regulating blade with the developing roller, and jitter occurs in the image due to the uneven rotation of the developing roller. Furthermore, in the case of the contact developing method in which the developing roller contacts the photoconductor, or in the case where another roller for replenishing toner is connected to the developing roller, the rotational torque is further increased, so that the jitter phenomenon is further deteriorated. Become. As a countermeasure against this, against the increase in rotational torque,
Although the driving force of the driving motor and the strength of the driving system may be increased, advantages of one-component development such as energy saving and weight reduction are hindered. In addition, since a large-diameter magnetic carrier such as in two-component development is not used, the cleaning effect on the toner layer is insufficient, and toner filming is likely to occur when the toner layer is repeatedly used for a long period of time. In one-component contact development in contact with the toner, toner filming on the photoconductor becomes a serious problem. Furthermore, due to repeated use for a long period of time, the surface of the developing roller is easily contaminated with toner components, and as described above, toner adheres to the toner surface side of the toner layer thickness regulating blade. This is sufficient, and background fogging is likely to occur. Further, when the toner fluidity is reduced, the image density is poor due to a decrease in the amount of toner supplied to the developing roller,
Background fogging occurs. To deal with these problems, efforts have been made from the toner side to solve the problems, especially by using fine powders other than silica.However, fundamental measures have not yet been taken. It is.

[0003]

SUMMARY OF THE INVENTION The present invention is an art for solving the above-mentioned problems of the prior art. That is, the first object of the present invention is to reduce the rotational torque between the developing roller and the photoreceptor in a one-component developing device including at least the developing roller and a toner layer thickness regulating blade that comes into contact with the developing roller. It is intended to provide a non-magnetic one-component toner in which a jitter image is eliminated by eliminating the problem. A second object of the present invention is to provide a non-magnetic one-component toner in which white streaks and background fog are eliminated by eliminating toner aggregation and adhesion on the toner surface side of the toner layer thickness regulating blade. is there.

A third object of the present invention is to provide a non-magnetic one-component toner capable of eliminating a decrease in image density and a background fog by eliminating toner filming on a photosensitive member and a developing roller. Further, a fourth object of the present invention is to provide a non-magnetic one-component toner in which a sufficient toner supply is ensured by eliminating poor toner fluidity to reduce image density reduction and background fog. Further, a fifth object of the present invention is to provide a long-term repeated use,
An object of the present invention is to extend the life of a developing device including a toner and a photoconductor without causing the above-described problems of the related art.

As a result of repeated improvements to achieve the above object, the present inventors have developed a non-magnetic one-component toner in which a fine powder of fluororesin, a fine powder of silica, and a fine powder of alumina are adhered to the toner surface. The object of the invention was achieved and the invention was completed.

[0006]

According to the first aspect of the present invention, there is provided a non-magnetic one-component toner used in a developing device having at least a developing roller and a toner layer thickness regulating blade abutting on the developing roller. The present invention is characterized in that fine particles of a fluororesin, fine particles of silica treated with silicon oil and fine particles of alumina are adhered to the surface of the toner. According to a second aspect of the present invention, in the non-magnetic one-component toner according to the first aspect, the silicon oil-treated silica fine powder has a polydimethylsiloxane group on a surface thereof, and an addition amount per 100 parts by weight of the toner is 0.8. ~ 1.6 parts by weight.

According to a third aspect of the present invention, in the non-magnetic one-component toner according to the first aspect, the alumina fine powder is selected from fused alumina and high-purity alumina, and the added amount per 100 parts by weight of the toner is 0.1. ~ 0.6 parts by weight. According to a fourth aspect of the present invention, there is provided the non-magnetic one-component toner according to the first aspect, wherein the fluororesin fine powder toner 1
It is characterized in that the amount added per 100 parts by weight is 0.2 to 1.0 part by weight.

[0008]

According to the present invention, since the fluorine resin fine powder on the toner surface acts as a lubricant, the load between the developing roller and the regulating blade and the load between the developing roller and the photosensitive drum can be reduced. Generation of jitter due to rotation unevenness of the system can be prevented. Further, since the silicon oil-treated silica fine powder on the toner surface can maintain the fluidity of the toner better than the hydrophobic silica produced by the usual silane compound, the toner is prevented from aggregating and adhering to the toner layer thickness regulating blade, and the image white streak is reduced. As a countermeasure, it also has a high negative charging property, so that the negative charging property of the toner can be maintained and the background fog can be eliminated. Further, the alumina fine powder on the toner surface has a high polishing effect. By actively polishing filming of the drum and the developing sleeve and fusion of the toner to the blade, the image density is reduced by the filming and the background is reduced. Fogging was eliminated. Here, the inventors, in particular,
It was found by electron microscopic observation that the silicon oil-treated silica was able to disperse the alumina fine powder that easily aggregated better than the conventional hydrophobic silica. From this, it was newly found that secondary defects such as scratches on the photoreceptor due to abrasive alumina fine powder could be effectively prevented. The silicon oil-treated silica and the alumina fine powder may be separately added to the toner, or may be previously dispersed and then added to the toner and dispersed.

As described above, the present invention eliminates jitter images by reducing friction with a fluorine-based resin fine powder, increases fluidity with a silicon oil-treated silica fine powder, and improves image whiteness and background fog by increasing negative chargeability. , Eliminates image density reduction,
Filming could be eliminated by adding a polishing effect using alumina fine powder. The combination of the above three types of fine powder is important,
If any one of them is missing, the effect of the missing component is essentially lost, so that the object of the present invention cannot be achieved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The silica used in the present invention has a polydimethylsiloxane group or the like on the surface by silicon oil treatment. In the present invention, the particle size of the silica is preferably 0.008 to 0.02 μm. By setting the particle size of the silicon oil-treated silica to 0.008 to 0.02 μm, the fluidity of the toner is improved, the toner supply amount to the developing roller is increased, and the background fog does not occur.
A sufficient image density can be obtained. The addition amount of silica treated with silicon oil per 100 parts by weight of toner is 0.8 to 1.6.
Part by weight is preferable, and 1.0 to 1.4 part by weight is particularly preferable. 0.8 ~ addition amount of silicon oil treated silica particles
When the content is 1.6 parts by weight, the background fogging is improved, and when the content is 1.0 to 1.4 parts by weight, the problem is solved.
If the amount is less than 0.8 part by weight, the effect of improving the fluidity of the toner is insufficient. If the amount exceeds 1.6 parts by weight, the dispersion of silica becomes poor, so that the image density defect and the background fog occur relatively early. As a result, the effect of extending the life of the developing device including the toner is shortened.

In the present invention, the particle size of the alumina is 0.2 to 0.2.
0.7 μm is preferred. By using alumina having a particle size of 0.2 to 0.7 μm, drum filming and toner fusion to a blade are prevented. The amount of the alumina particles added per 100 parts by weight of the toner is preferably 0.1 to 0.6 parts by weight, and particularly preferably 0.15 to 0.4 parts by weight. Drum filming and image white streaks were improved by adjusting the amount of added alumina to 0.1 to 0.6 parts.
The problem is solved by using parts by weight. When the amount is less than 0.1 parts by weight, the effect of preventing toner fusion is insufficient, and drum filming and white stripes occur relatively early. If the amount exceeds 0.6 parts by weight, the image density decreases relatively early.

The fluororesin fine powder used in the present invention includes fine powders of homopolymers and copolymers of fluorine-containing monomers such as polytetrafluoroethylene, trifluoroethylene, vinylidene fluoride and fluoroethylene. Powders or fine powders of a copolymer of a fluorine-containing monomer and another ethylene-based monomer can be used. The effects of the invention are not particularly limited to the molecular weight and melting point of the fluororesin fine powder. In the present invention, the particle size of the fluororesin fine powder is 1 to
12 μm is preferred. By using a fine powder of fluororesin having a particle diameter of 1 to 12 μm, image jitter is improved.
The addition amount of the fluororesin fine powder per 100 parts by weight of the toner is preferably 0.2 to 1.0 part by weight, particularly preferably 0.3 to 0.6 part by weight. By adjusting the amount of addition to 0.2 to 1.0 part by weight, the image jitter is improved.
The problem is solved by setting it to 0 parts by weight. If the amount is less than 0.2 parts by weight, the image jitter may exceed 1.0 parts by weight, and drum filming may occur relatively early.

In the present invention, as the toner particles to which each fine powder adheres to the surface, any known toner conventionally used in dry development can be used. Such a toner is produced by dispersing a colorant and, if necessary, a release agent, a charge control agent, a small amount of magnetic powder and the like in a fixing resin. Examples of the fixing resin for toner used in the present invention include polystyrene, poly-α-methylstyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl acetate copolymer, and styrene-maleic acid copolymer. Polymers, styrene-acrylate copolymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, etc.), styrene-methacrylate copolymer ( Styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer),
Styrene-based resins (homopolymers or copolymers containing styrene or styrene substituents) such as styrene-α-methyl methyl acrylate copolymer and styrene-acrylonitrile-acrylate copolymer, ethylene-ethyl acrylate Examples thereof include a polymer, an ethylene-vinyl acetate copolymer, a rosin-modified maleic acid resin, an epoxy resin, and a polyester resin. These may be used alone or as a mixture of two or more.

Examples of the release agent for toner (offset preventing agent) used in the present invention include aliphatic hydrocarbons, aliphatic metal salts, higher fatty acids, fatty acid esters or partially saponified products thereof, silicone oil, Various waxes can be mentioned. Among them, the weight average molecular weight is 1000-1
Aliphatic hydrocarbons of about 0000 are preferred. Specifically, low molecular weight polyethylene, low molecular weight polypropylene,
One or a combination of two or more of paraffin wax, a low-molecular-weight olefin polymer composed of olefin units having 4 or more carbon atoms is suitable. As the colorant for the toner used in the present invention, besides carbon black, a color pigment and a color dye which can be used for ordinary color toners can be used. As the carbon black, channel black, gas furnace black, oil furnace black, thermal black, acetylene black and the like are used. As the colorant for color, an azo-based pigment, a benzidine-based pigment (for yellow toner), a quinacridone-based pigment (for magenta toner), a copper phthalocyanine-based pigment (for cyan toner), and the like are used.

As the charge control agent for controlling the negative charge used in the present invention, various metal-containing organic complexes are used, but even if an acidic group is introduced into the fixing resin without using the charge control agent. Good. Other external treatment agents that are appropriately added include hydrophobic silica, titanium oxide, vapor phase alumina, magnetite,
A metal oxide such as cerium oxide may be used, or various resin fine powders may be used.

[0016]

[Evaluator] A printer having a printing speed of 5 sheets (A4) / min by the following non-magnetic one-component developing system was used as a copying machine. The photoreceptor drum used had a laminated photoreceptor layer comprising a polycarbonate resin layer on the surface and a butyral resin layer having an azo pigment dispersed in the lower layer provided on the surface of an aluminum tube having a diameter of 20 mm. A main charger as a charging unit, an image exposure device, a developing device, a transfer charger as a transfer unit, and a cleaning device having a cleaning blade are arranged along the rotation direction of the photoconductor. The photoreceptor is -7 by corona discharge of main charge.
After being uniformly charged to 00 V, exposure operation is performed with a laser beam modulated by an image signal to attenuate to -100 V in a development area to form an electrostatic latent image corresponding to the image exposure. The developing device has a thickness of 0.2 mm for a developing roller having a diameter of 15 mm made of urethane rubber in which carbon or the like is dispersed.
Stainless steel blade is pressed. A developing bias voltage of -400 V is applied to the developing roller. The fixing unit is of a hot roll type. The surface of the upper roller to which the toner contacts is coated with Teflon, a halogen lamp is built in, and the surface temperature is controlled to 170 ° C. The lower roller is made of silicone rubber.

[0017]

[Toner Production Example] 100 parts by weight of polyester resin (Tm 135 ° C., Tg 60 ° C.) 4 parts by weight MA-100 (carbon black manufactured by Mitsubishi Chemical) NP055P (low molecular weight polypropylene manufactured by Mitsui Chemicals) 3 parts by weight Bontron S34 (manufactured by Orient Chemical Co., Ltd.) Charge control agent) 2 parts by weight From the above materials, go through the process of mixing (Henschel mixer) → kneading (biaxial extruder) → coarse grinding (hammer mill) → fine grinding (jet mill) → classification (wind classifier) Toner particles having an average particle diameter of 9.5 μm (median diameter measured by a Coulter counter) were obtained.

As silicon oil-treated silica fine powder,
A hydrophilic silica fine powder having an average particle diameter of 0.014 μm was subjected to a hydrophobic treatment with dimethyl silicone oil to use a powder having a polydimethylsiloxane group on the surface.
R974 (mean diameter 0.012) was used as comparative silica.
μm, containing a dimethylsilyl group on the surface, manufactured by Nippon Aerosil Co., Ltd.). As an alumina fine powder, an average particle diameter of 0.
6 μm fused alumina fine powder was used. Tetrafluoroethylene fine powder having an average diameter of 4 μm was used as the fluorine-based resin fine powder. Here, the particle size of each fine powder in the present invention is a primary particle size visually determined by an electron microscope photograph.

With respect to 100 parts by weight of the obtained toner particles, according to Tables 1, 2, and 3 of Examples described later,
Each of the fine powders was added and mixed at a high speed using a Henschel mixer to produce a product toner. The results of a print test performed by an evaluation tester are also shown in Tables 1, 2 and 3. "Parts" in the table means "parts by weight".

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

Example 1 Good quality was obtained through 10,000 prints.

[0024]

Example 2 At the end of 10,000 sheets, slight image dirt due to filming was observed, but within the practical range, and good quality was obtained in other cases.

[0025]

Example 3 Good quality was obtained through 10,000 prints.

[0026]

Example 4 Good quality was obtained through 10,000 prints.

[0027]

Example 5 At the end of printing 10,000 sheets, white streaks, background fogging, and image jitter were slightly observed, but were within the practical range, and good quality was obtained in other cases.

[0028]

[Embodiment 6] At the end of printing 10,000 sheets, both the image white streak and the background fog quality have not reached the practical level. Good quality was obtained for 5,000 prints.

[0029]

Seventh Embodiment At the end of printing 10,000 sheets, the quality of background fogging has not reached a practical level. Good results were obtained for 5,000 prints.

[0030]

Eighth Embodiment At the end of printing 10,000 sheets, the quality of image stains due to filming has not reached a practical level. For 5,000 prints, a quality that was practically acceptable was obtained.

[0031]

Ninth Embodiment At the end of printing 10,000 sheets, the image density is too low to reach a practical level. With respect to 5,000 prints, practically no problematic quality was obtained.

[0032]

Embodiment 10 At the end of printing 10,000 sheets, the quality of image jitter has not reached a practical level. With respect to 5,000 prints, practically no problematic quality was obtained.

[0033]

Embodiment 11 At the end of printing 10,000 sheets, the quality of image stains due to filming has not reached a practical level. For 5,000 prints, a quality that was practically acceptable was obtained.

[0034]

[Comparative Example 1] At the end of printing 1,000 sheets, the test was stopped because quality defects such as image white streaks, background fogging and filming occurred.

[0035]

[Comparative Example 2] At the end of the printing of 1,000 sheets, the test was stopped because a quality defect of the jitter image occurred.

[0036]

[Comparative Example 3] The test was stopped because quality defects such as low image density, background fog, and white image streaks occurred at the end of printing 1,000 sheets. Also, image black streaks due to drum scratches were observed.

[0037]

[Comparative Example 4] At the end of the printing of 1,000 sheets, the test was stopped because quality defects such as white stripes and background fogging occurred. Also, image black streaks due to drum scratches were observed.

[0038]

According to the present invention, fine particles of fluorine resin, fine particles of silica treated with silicon oil, and fine particles of alumina are adhered to the surface of a toner for non-magnetic one-component development, and image jitter is eliminated by reducing friction with the fluorine resin fine powder. In addition, white fluid lines, background fogging, and image density reduction were eliminated by increasing the fluidity and increasing the negative chargeability of the silicon oil-treated silica fine powder, and the filming was eliminated by imparting a polishing effect using the alumina fine powder. In particular, the silicon oil-treated silica disperses the alumina fine powder in a state close to the primary particle diameter, thereby preventing drum damage. 1

Claims (4)

[Claims] 1. A non-magnetic one-component toner for use in a developing device having at least a developing roller and a toner layer thickness regulating blade abutting on the developing roller, wherein the surface of the toner particles has a silica fine powder treated with silicon oil. Non-magnetic one-component toner obtained by adhering alumina fine powder and fluorine resin fine powder. 2. The silicon oil-treated silica fine powder has a polydimethylsiloxane group on its surface.
2. The non-magnetic one-component toner according to claim 1, wherein the amount added per 0 part by weight is 0.8 to 1.6 parts by weight. 3. The method according to claim 1, wherein the alumina fine powder is selected from fused alumina and high-purity alumina, and the amount added is 0.1 to 0.6 parts by weight per 100 parts by weight of the toner. 3. The non-magnetic one-component toner according to 2. 4. The non-magnetic material according to claim 1, wherein the amount of said fluorine resin fine powder is 0.2 to 1.0 part by weight per 100 parts by weight of the toner. Component toner.