JP2003043725A - Image forming method, one-component developer used for the same and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for one-component developer which is immune to thermal stress and mechanical stress exerted on the toner and by which a stable image is obtained, and oil-less fixing electrophotographic image forming method and image forming device using the toner. SOLUTION: 1. In the oil-less fixing electrophotographic image forming method, development is performed by using the one-component developer consisting of toner in which wax is dispersed and whose coefficient of dynamic friction is 0.20 to 0.45 on a condition that the speed of the developing roller of the electrophotographic image forming device is 25 to 85 cm/sec, abutting pressure by a triboelectric charge imparting member is >=30 g/cm, and the passing amount of the developer after passing the triboelectric charge imparting member is 0.02 to 0.12 g/(cm×sec) 2. The one- component developer for the oil-less fixing electrophotographic image forming method consists of the toner in which wax is dispersed and whose coefficient of dynamic friction is 0.20 to 0.45, and which is used under a developing condition that the speed of the developing roller of the electrophotographic image forming device is 25 to 85 cm/sec, the abutting pressure by the triboelectric charge imparting member is >=30 g/cm and the passing amount of the developer after passing the triboelectric charge imparting member is 0.02 to 0.12 g/(cm×sec).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming method employing oilless fixing, a one-component developer used in the method, and an image forming apparatus.

[0002]

2. Description of the Related Art An image forming method using a one-component developer in electrophotography is widely known and is used in printers, facsimiles, copying machines and the like. Recently, JP-A-60-41079
As disclosed in Japanese Patent Publication, after developing the latent image formed on the photoconductor drum with toner and transferring this to a transfer material such as plain paper, the toner remaining on the photoconductor drum is removed with a cleaner. However, the removed toner is often returned to the developing device for reuse. Further, as disclosed in Japanese Patent Laid-Open No. 7-199538,
As a toner capable of forming good image quality for a long time with little toner deterioration even in a low-temperature fixing recycling system, as a fluidity improver, there are two types of additives: an additive for increasing the charge amount and an additive for decreasing the charge amount ( A toner has been proposed in which carnauba wax or the like is added as a release agent.

[0003]

By the way, recently, many copiers are also provided with a printer function, and the output of only one copy or one print is increased. The stirring time is getting longer. In the developing device, stirring of the developer greatly affects the deterioration of the developer. The developer is pressed against the developing roller by an elastic blade or a sponge roller before being conveyed to the developing area. As a result, the temperature of the developer rises and the toner component locally adheres to the developing roller. A wax is dispersed in the oilless toner in order to secure the releasability of fixing, but when heat stress is applied to this toner, the wax is exposed on the toner surface, and the wax is excessive, and the wax is also on the developing roller surface. Will be attached. As a result, when the toner polarity is negative, an appropriate amount of triboelectrification cannot be obtained even if the wax of the same polarity adheres to the developing roller and is pressed by the triboelectrification imparting member.

Further, as an image density control system, a system is used in which the darkness of the adhered toner on the photoconductor is optically detected to control the potential related to development. As a result, when the toner charge amount decreases, the control for decreasing the developing bias is added, so that there occurs a problem that the saturated image density does not appear even though the development γ characteristic stands up to the intermediate image density range. As a result, problems such as a decrease in image density and poor sharpness occur, but the problem is particularly serious in high-speed machines.

In order to impart a proper triboelectric charging property to the toner quickly, it is necessary to set the contact pressure of the triboelectric charging member to the developing roller to 30 g / cm or more. Normally, the rotation speed of the developing roller is 1.0 to
It is used at a speed of 2.0 times. At this time, the developer passing amount of the frictional charge imparting member of the developing device is 1 cm per second.
The width is 0.02 to 0.12 g. (Developer speed 25 to 85 cm / sec, amount of developer on sleeve: 0.8 to 1.2 g / 1 cm ² ) The above problem occurs under these conditions. When the amount is less than or equal to the amount of the frictional charge imparting member, the stress of the agent is small and it is not a big problem. On the other hand, if the value is more than this value, the condition becomes worse and it becomes difficult to deal with the toner.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional technique, it is an object of the present invention to provide a toner for a one-component developer which is resistant to heat stress and mechanical stress on the toner and which can obtain a stable image.

[0007]

According to the present invention, there is provided a one-component developer comprising a wax-dispersed toner, and in an electrophotographic image forming apparatus employing an oilless fixing system, the developing roller speed for development is 25 to At 85 cm / sec, the contact pressure by the triboelectric charging member is 30 g / cm or more, and the developer passing amount after passing through the triboelectric charging member is 0.02 to 0.12.
A toner used in an electrophotographic image forming apparatus having g / (cm · sec) and having a dynamic friction coefficient of 0.20 to 0.45, an image forming method using the toner, and The above-mentioned problem can be solved by an image forming apparatus equipped with the toner.

That is, in the high-speed machine to which the present invention is applied, the contact pressure by the frictional charge imparting member is strong, and 0 is set below the increased frictional charge imparting member (the gap between the frictional charge imparting member and the developing roller). 0.02 to 0.12 g / (cm · se
Since a large amount of the developer c) passes through, the amount of heat generated by frictional heat and the like is overwhelmingly larger than in a model that does not employ such developing conditions. The present invention provides a toner in which the wax does not exude even if it is heated under the pressure of the frictional charge imparting member as described above, and by combining the toner with the high-speed machine targeted by the present invention, the toner is always stable. An image forming apparatus and an image forming method proposal capable of obtaining an image could be provided.

In the present invention, in order to suppress the exudation of the wax dispersed in the toner, it is preferable to control the wax component so that the wax component does not exist on the toner surface as much as possible. As a result of the inventors' earnest studies on means for achieving the above, if the friction coefficient of the pellet obtained by pressure-molding the toner powder falls within the range of 0.20 to 0.45, the above-mentioned problems are overcome, and the present invention is achieved. In the high-speed type electrophotographic image forming apparatus in which the contact pressure by the frictional charging member is strong,
The inventors have found that it is possible to determine that the toner does not exude the wax in the toner even when subjected to severe mechanical stress, and thus the present invention has been accomplished.

Here, the dynamic friction coefficient of the binder resin, which generally occupies most of the toner component, is about 0.5, and that of wax is about 0.1. That is, it was confirmed that when a large amount of wax was present on the toner surface, the dynamic friction coefficient was below 0.20, and when the wax was properly present on the toner surface, it was within 0.45. If the coefficient of kinetic friction exceeds 0.45, almost no wax is present on the toner surface, which causes a problem of causing fixing offset.

Rice wax or ester wax is used as the wax dispersed in the toner of the present invention. These waxes have very good dispersibility at the time of kneading the toner, and are suitable as the wax used in the present invention.

The raw material particle size of the wax dispersed in the toner of the present invention is preferably 100 to 300 μm. That is, if the particle size of the wax at the time of the raw material is controlled to be small, the wax dispersion size controlled in the toner kneading step also becomes small, so that the toner does not exude the wax even when subjected to heat stress and / or mechanical stress. Can be configured.

In the present invention, it is preferable to use the wax obtained by the spray drying method. The wax obtained by the spray-dry manufacturing method has a very uniform particle size distribution and does not contain coarse wax particles, so even if a toner is manufactured using it, the wax will be dispersed uniformly in the toner. This is a preferable condition for the toner of the present invention. Conventionally, the raw material particle diameter of a general wax is around 600 μm, but when the wax is used for very normal kneading, the wax dispersion diameter at the time of dispersion may exceed 10 μm. When the material is pulverized / classified to be made into a toner, most of the toner particles are composed of a wax component, so that the developer of the present invention cannot be said to be in a preferable state. Further, when the average particle diameter of the wax is 100 μm or less, the dispersed diameter in the toner becomes small, and the low temperature fixing property and the offset property deteriorate. The dispersed diameter of the wax in the toner is obtained by image analysis of a photographic image of the wax particles taken by a transmission scanning electron microscope of the toner using an image analyzer Luzex IIIU (manufactured by Nireco).

The toner of the present invention has a circularity of 0.
It is preferably 94 or more. That is, it is preferable that the toner is composed of a toner having a high circularity. The toner of the present invention can maintain high fluidity when used as a one-component developer by adopting a configuration in which the circularity of the toner is 0.94 or more, and the toner can be developed by the developing sleeve as in the image forming apparatus of the present invention. Even if the agent is transported at high speed, the fluidity is high, so stress is not easily received under the doctor.

A feature of the present invention is that the loose apparent density of the toner is 0.3 or more. The loose apparent density of the toner represents the tightness (density) of the toner that has been allowed to stand. When the additives and the like are attached to the surface of the toner, the fluidity of the powder as a powder is improved, the particles are easily tightened, and the density is increased. Therefore, the fact that the loosening apparent density is large means that the surface of the toner is sufficiently covered with the inorganic fine powder. With this structure, the surface of the toner is sufficiently protected by the inorganic fine powder, so that the structure is also less susceptible to stress under the frictional charge imparting member. As the external additive having a high toner surface protection effect, alumina having a Mohs hardness of 9 is mentioned, and the overwhelming hardness protects the toner surface from stress. On the other hand, even when the inorganic fine powder treated with silicone oil is used, it has been found that the releasing property peculiar to silicone oil has the effect of protecting the toner surface from mechanical stress.

The toner of the present invention preferably has an aggregation degree of 30% or less. The cohesion of the toner means the adhesive force between the toner particles, and the large cohesion means that the surface of the toner contains many wax components. Here, when the cohesion exceeds 30%, a large amount of wax component is present on the toner surface, and when used in the high speed machine of the present invention, the wax component of the toner easily contaminates the developing roller surface, The triboelectrification property as a developer is deteriorated, resulting in a decrease in developing ability and frequent background stains.

In the toner of the present invention, the organometallic compound is zirconium and an aromatic compound selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids and aromatic polycarboxylic acids. Preference is given to using organozirconium compounds which are coordinated and / or bound. It is considered that zirconium ions cause metal cross-linking of the wax component even if only a small amount of the above compound is contained, and it is considered that the wax component itself deteriorates so as not to contaminate the developing roller itself.

The toner of the present invention is preferably combined with a polymerized toner. The characteristics of the polymerized toner are that the wax is easily included, resulting in a high friction coefficient and a high circularity due to the absence of a crushing interface. Since the external additive is applied to the place where the circularity is high, the fluidity is very good, so it can be said that the toner is the most suitable for the toner of the present invention.

The image forming apparatus of the present invention preferably has a developing roller surface coated with a silicone resin. The characteristic of the silicone resin is its good releasability, and the developing roller is less likely to be contaminated. It is also preferable that an aminosilane coupling agent is present on the surface of the developing roller. The aminosilane coupling agent has good adhesiveness to the surface of the developing roller, and also has a characteristic that it is less likely to cause background stains because it provides a proper charge amount to the toner due to the positive polarity of the amino group. ing. In the image forming apparatus of the present invention, the development gap is preferably 0.05 to 0.2 mm. Further, it is more preferably 0.05 to 0.10 mm. In the present invention, the developing roller speed is 25 to
Since the target is a high-speed machine of 85 cm / sec, if the developing gap is less than 0.05 mm, the stress when passing the developer through the gap becomes too large and the developer is apt to deteriorate. On the other hand, the development gap is 0.
If it exceeds 2 mm, the amount of developer passing through the developing area becomes too large, and the surface of the photoconductor is likely to be damaged and deteriorated.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically by way of embodiments. As the wax component used in the present invention, it is preferable to use carnauba wax, rice wax, synthetic ester wax, and a mixture thereof. Particularly, it is preferable to use rice wax and / or synthetic ester wax. The carnauba wax is a natural wax obtained from the leaves of carnauba palm, but a low acid value type desorbed free fatty acid is particularly preferable because it can be uniformly dispersed in the binder resin. Rice wax is a natural wax obtained by refining crude wax produced in a dewaxing or wintering process when refining rice bran oil extracted from rice bran. The synthetic ester wax is synthesized from a monofunctional linear fatty acid and a monofunctional linear alcohol by an ester reaction. These wax components are used alone or in combination. The amount of the wax component added is preferably 0.5 to 10 parts by weight.

As the binder resin used in the toner of the present invention, all conventionally known resins can be used. For example, styrene, poly-α-stillstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene. -Styrene such as maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer -Based resin (styrene or styrene-substituted homopolymer or copolymer), polyester resin, epoxy resin, vinyl chloride resin, rosin-modified maleic acid resin,
Phenol resin, polyethylene resin, polypropylene resin, petroleum resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyrate resin and the like can be mentioned. These resins can be used alone or in combination of two or more.
The method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization can be used.

Further, as the external additive for the toner of the present invention,
Inorganic fine particles can be preferably used. The inorganic fine particles have a primary particle diameter of preferably 5 mμ to 2 μm, more preferably 5 mμ to 500 mμ, and BE
The specific surface area according to the T method is preferably 20 to 500 m ² / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5% by weight of the toner, and particularly 0.0
It is preferably from 1 to 2.0% by weight.

Specific examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, and the like.
Mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengulas, antimony trioxide, magnesium oxide,
Examples thereof include zirconium oxide, parium sulfate, barium carbonate, calcium carbonate, silicon carbide and silicon nitride. Of these, alumina is preferred.

In addition, high-molecular fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, polycondensation system of methacrylic acid ester and acrylic acid ester copolymer, silicone, benzoguanamine and nylon, heat Polymer particles made of a curable resin may be used.

Such an external additive, that is, a fluidizing agent, can be surface-treated to increase its hydrophobicity and prevent deterioration of fluidity characteristics and charging characteristics even under high humidity. For example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, a silicone oil, an organic titanate-based coupling agent, an aluminum-based coupling agent and the like can be mentioned as preferable surface treatment agents.

To add the fluidizing agent to the above toner, a mixer such as a super mixer or a Henschel mixer is used.

The developer of the present invention may contain a charge control agent, if necessary. All known charge control agents can be used, for example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdic acid chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine modified (Including quaternary ammonium salts), alkylamides, phosphorus alone or compounds,
Examples include simple substances or compounds of tungsten, fluorine-based activators, salicylic acid metal salts, and salicylic acid derivative metal salts.

Specifically, the Nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, and the salicylic acid metal complex. E-8
4, E-89 (above, manufactured by Orient Chemical Industry Co., Ltd.) of a phenol-based condensate, TP-302, TP-415 (above manufactured by Hodogaya Chemical Industry Co., Ltd.) of a quaternary ammonium salt molybdenum complex, quaternary ammonium Salt copy charge PSY
VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt N
EG VP2036, Copy Charge NX VP43
4 (above, manufactured by Hoechst), LRA-901, a boron complex LR-147 (manufactured by Nippon Kalit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, other sulfonic acid groups, carboxyl groups, quaternary Examples thereof include polymer compounds having a functional group such as ammonium salt.

(Measurement method of each characteristic) 1. Toner surface friction coefficient The surface friction coefficient is measured using a fully automatic friction and wear analysis device manufactured by Kyowa Interface Science Co., Ltd., which is obtained by applying a load of 6 t / cm ² to a toner having a mass of 3 g to make a disk-shaped pellet having a diameter of 40 mm. At this time, a 3 mm stainless ball point contactor is used as the contactor.

2. Wax raw material particle size There are a measuring method using a vibration screen and a measuring method using a laser. An example of the laser method is shown below. Device: Horiba Seisakusho, LA-920 Conditions: Circulation rate 5-7 ml / sec, dispersion medium methanol

3. Circularity flow type particle image analyzer (Flow Particle)
The measurement method using the Image Analyzer will be described below. The measurement of the toner, the toner particles and the external additive by a flow type particle image analyzer is performed, for example, by a flow type particle image analyzer FPIA-1 manufactured by Toa Medical Electronics.
000 can be used for measurement. The measurement removes fine dust through the filter, resulting in 1
Underwater measurement range of 0-3cm ³ (e.g., a circle equivalent diameter 0.
A few drops of a nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.) are added to 10 ml of water having a particle number of 60 μm or more and less than 159.21 μm) of 20 or less, and 5 mg of a measurement sample is further added. Sonic disperser (STM UH-
50), the dispersion treatment is performed for 1 minute under the condition of 20 kHz and 50 W / 10 cm ³ and further, the dispersion treatment is performed for a total of 5 minutes, and the particle concentration of the measurement sample is 4000 to 8000 particles / 10c.
The particle size distribution of particles having a circle equivalent diameter of 0.60 μm or more and less than 159.21 μm is measured using a sample dispersion of m ³ (for particles in the circle equivalent diameter range for measurement). The sample dispersion is a flat and flat transparent flow cell (thickness: about 20).
0 μm) flow path (which spreads along the flow direction). A strobe and a CCD camera are mounted on opposite sides of the flow cell to form an optical path that intersects and passes through the thickness of the flow cell. While the sample dispersion is flowing, the strobe light is 1/30 to obtain an image of the particles flowing through the flow cell.
Irradiation is performed at intervals of seconds, so that each particle is captured as a two-dimensional image having a certain area parallel to the flow cell. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The equivalent circle diameter of 1200 or more particles can be measured in about 1 minute, and the number based on the equivalent circle diameter distribution and the proportion (number%) of particles having a prescribed equivalent circle diameter can be measured. The results (frequency% and cumulative%) are 0.06 as shown in Table 1.
It can be obtained by dividing the range of −400 μm into 226 channels (divided into 30 channels for one octave). In actual measurement, the equivalent circle diameter is 0.60 μm or more 1
Particles are measured in the range of less than 59.21 μm.

4. Looseness apparent density Measured with a powder tester PT-N type (manufactured by Hosokawa Micron).

5. Particle size distribution Coulter counter TA-II and Coulter Multisizer II (both manufactured by Coulter Co.)
Can be given. The measuring method is described below. First,
0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is an about 1% NaCl aqueous solution prepared using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter, Inc.) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is about 1 to 3 with an ultrasonic disperser.
A dispersion treatment is performed for a minute, and the volume and number of toner particles or toner are measured by the measuring device using a 100 μm aperture as an aperture to calculate a volume distribution and a number distribution. From the obtained distribution, the weight average particle diameter (Dw) and the number average particle diameter of the toner can be obtained. As a channel, 0 to less than 1.26 μm; 1.26 to
Less than 1.59; 1.59 to less than 2.00; 2.00
Less than 2.52 μm; less than 2.52 to 3.17 μm;
17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6.35 to 8.00
Less than μm; 8.00 to less than 10.08 μm; 10.08
~ 12.70 μm; 12.70 ~ 16.00 μm; 16.00 ~ 20.20 μm; 20.20-2
Less than 5.40 μm; 25.40 to less than 32.00 μm;
16 channels of 32.00 to less than 40.30 μm are used, and particles having a particle size of 2.00 μm or more and less than 40.30 μm are targeted.

6. Aggregation Degree The aggregation degree is measured as follows. The measuring device is
Using Hosokawa Micron's powder tester, set the accessory parts on the vibrating table in the following procedure. (A) Vibro chute (b) Packing (c) Space ring (d) Fluid (3 types) Top>Middle> Bottom (e) Osaver Ever fix with a knob nut and operate the vibrating table. The measurement conditions are as follows. Screen opening (top) 75 μm Screen opening (middle) 45 μm Screen opening (bottom) 22 μm Swing scale 1 mm Sampling amount 10 g Vibration time 30 seconds After measurement, determine the degree of aggregation from the following calculation.

[Equation 1] The sum of the above three calculated values is defined as the aggregation degree (%).
That is, aggregation value (%) = (a) + (b) + (c).

(Image Forming Apparatus) FIG. 1 shows an example of the image forming apparatus of the present invention. On the electrophotographic photoreceptor or electrostatic recording dielectric, which is an electrostatic latent image carrier that has been uniformly charged in advance,
An electrostatic latent image is formed by exposure means such as an optical system that scans a semiconductor laser, which is modulated by pixel information. As a developing device for developing this electrostatic latent image, for example, a developer is transferred onto the electrostatic latent image carrier from a developer carrier which has a predetermined minute gap in a developing region facing the electrostatic latent image carrier. It is known that the electrostatic latent image is developed by transferring and applying the electrostatic latent image. The developed image is transferred to the transfer material by the transfer means. The transfer material onto which the toner image has been transferred is separated from the electrostatic latent image carrier and sent to a fixing means such as a known heating fixing device (not shown), where the toner image is fixed to the transfer material. The transfer material that has passed through the fixing unit is discharged to the outside of the image forming apparatus.

As shown in FIG. 1, the developing device 10 is installed so as to face a drum-shaped electrophotographic photosensitive member which is an image carrier of the developing device and rotates in the direction of the arrow, that is, the photosensitive drum 1. An electrostatic latent image is formed on the surface by a known electrostatic latent image forming means 20 including a charger and an exposing means. As the exposing means, a means for projecting an optical image of an original, an optical system for scanning a laser beam modulated by a recorded image signal, or the like is adopted, and the latent image formed on the photosensitive drum 1 is developed by the developing device 10. And a toner image is formed. The obtained toner image is transferred to a transfer material such as paper by a known transfer unit 30 including a transfer charger and the like. The transfer material onto which the toner image has been transferred is separated from the photosensitive drum 1 and sent to a known fixing unit (not shown). Therefore, the toner image is fixed on the transfer material.

The toner remaining on the photosensitive drum 1 after the transfer is removed by a known cleaning means 40 using a cleaning blade. The cleaning blade has a hardness of about 65 ° (JISA), is fixed to a blade holder made of a steel plate, and comes into contact with the photosensitive drum 1 with a penetration amount of 0.5 to 1 mm for cleaning.

The developing device 10 contains an insulating one-component developer 11 containing no carrier particles in a developing container 12. The developer 11 is mainly composed of an insulating toner, and preferably, silica fine powder is slightly added externally. The silica fine powder is added externally for the purpose of controlling the triboelectric charge of the toner so as to increase the image density and obtain an image with less roughness. For example, it is known to externally add vapor phase production silica (dry silica) and / or wet production silica (wet silica) to the toner.

The one-component developer, that is, the toner 11 is taken out of the container 12 by the non-magnetic developing roller 14 which is a developer carrying member and which rotates in the direction of the arrow and is made of aluminum, stainless steel or the like, and a developing area facing the photosensitive drum 1. It is transported to 13. In the developing area 13, the photosensitive drum 1 and the developing roller 14 face each other with a minute gap of 300 μm therebetween, but a desired minute gap was set in the following experiment.
In the developing area 13, the toner 11 is transferred and applied to the electrostatic latent image on the photosensitive drum 1, and the electrostatic latent image is developed as a toner image. When magnetic toner is used, a magnet may be installed inside the developing roller.

Here, the triboelectric charging member installed before being conveyed to the developing area 13 will be described. The thickness of the developer layer 11 a on the developing roller 14 is controlled by the elastic blade 16. The elastic blade 16 is made of an elastic material such as urethane rubber and has a thickness of 1 to 1.5 mm,
The free length is about 10 mm, the contact pressure is about 30 g / cm,
It is fixed to a steel plate holder and abuts on the developing roller 14. This blade 16 forms a thin developer layer 11 a on the developing roller 14. Further, the frictional charge imparting member is not limited to this elastic blade, and may be an elastic roller capable of forming an equivalent contact pressure.

As described above, non-contact development is performed in the developing device shown in FIG. That is, the development area 13
Since the thickness of the toner layer 11a conveyed to the toner is smaller than the minute gap between the developing roller 14 and the photosensitive drum 1, the toner 11
Flies over the air gap from the developing roller 14 and the photosensitive drum 1
To reach. Then, in order to improve the developing efficiency at that time, and to form a developed image having a high density and being clear and suppressing the background stain, a developing bias voltage containing an AC component is applied to the developing roller 14 from the bias power source 50.

In this embodiment, when a latent image having a dark portion potential of -700 V and a light portion potential of -150 V is subjected to reversal development with negatively charged toner, the developing bias voltage has a DC component of-.
550V, AC component has peak-to-peak voltage of 1.
A rectangular wave voltage of 0 kV and a frequency of 3.0 kHz was used. Due to the bias voltage, the electric field in the direction in which the toner 11 is transferred from the developing roller 14 to the photosensitive drum 1 and the electric field in the direction in which the toner 11 is reversely transferred to the developing roller 14 act alternately. As a result, a good developed image can be obtained. The toner 11 is mainly composed of the developing roller 14.
It is charged to the polarity that develops the electrostatic latent image by friction with.
As the toner 11, the toners 1 to 12 were prepared and prepared as follows.

[0043]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. The parts here are based on weight.

[0044] (Example 1)   Toner 1:     Polyester resin (Mw: 6000,       Tm105 ° C, acid value 28mgKOH / g) 90 parts     Polyester resin (Mw: 80,000,       Tm 143 ° C., acid value 20 mg KOH / g) 10 parts     Carnauba wax (melting point 82 ° C, volume average particle size 590 μm) 5 parts     8 parts of carbon black (# 44: Mitsubishi Kasei)     3,5-Di-tert-butyl iron salicylate 2 parts

The mixture having the above composition was sufficiently agitated and mixed in a Henschel mixer, heated and melted at a temperature of 90 to 100 ° C. for about 30 minutes by a roll mill, and cooled to room temperature, and the obtained kneaded product α was jet-milled. After crushing and classifying with a wind classifier,
To 100 parts of this toner base particle, silica (R97
4, 1.0 parts of Nippon Aerosil Co., Ltd. and 0.5 parts of titania (T805 Nippon Aerosil Co., Ltd.) were added, and after stirring and mixing with a Henschel mixer, the particles of large particle size were removed through a mesh, and the particles shown in Table 1 were added. Toner 1 having a diameter distribution was obtained. In Table 1, CH is a channel and N is a particle count number. Dynamic friction coefficient 0.28, circularity 0.91, loose apparent density 0.33 g / cm ³ , cohesion 33%, wax average dispersion diameter 1.4 μm

[0046]

[Table 1]

(Embodiment 2) Toner 2: Toner 1 is prepared by rolling a roll mill to 110-1.
Toner 2 was obtained in the same manner except that it was heated and melted at a temperature of 20 ° C. Dynamic friction coefficient 0.20, circularity 0.91,
Loose apparent density 0.33 g / cm ³ , cohesion 33%,
Wax average dispersion diameter 1.6 μm

(Example 3) Toner 3: Toner 1 was used, which was 130 to 1 with a roll mill.
Toner 3 was obtained in the same manner except that it was heated and melted at a temperature of 40 ° C. Dynamic friction coefficient 0.15, circularity 0.91,
Loose apparent density 0.32 g / cm ³ , aggregation degree 34%,
Wax average dispersion diameter 2.0 μm

[0049] (Example 4)   Toner 4:     Polyester resin (Mw: 6000,       Tm105 ° C, acid value 28mgKOH / g) 90 parts     Polyester resin (Mw: 80,000,       Tm 143 ° C., acid value 20 mg KOH / g) 10 parts     Rice wax (melting point 78 ° C, volume average particle size 480 μm) 5 parts     8 parts of carbon black (# 44: Mitsubishi Kasei)     3,5-Di-tert-butyl iron salicylate 2 parts

The mixture having the above composition was sufficiently agitated and mixed in a Henschel mixer, heated and melted at a temperature of 90 to 100 ° C. for about 30 minutes by a roll mill, and cooled to room temperature, and then the obtained kneaded product β was jet-milled. After crushing and classifying with a wind classifier,
To 100 parts of this toner base particle, silica (R97
4, 1.0 parts of Nippon Aerosil Co., Ltd. and 0.5 parts of titania (T805 Japan Aerosil Co., Ltd.) were added, and after stirring and mixing with a Henschel mixer, large particles were removed through a mesh to obtain Toner 4. . Dynamic friction coefficient 0.29,
Roundness 0.91, loose apparent density 0.34 g / c
m ³ , cohesion 32%, wax average dispersion diameter 1.2 μm

(Example 5) Toner 5: Polyester resin (Mw: 6000, Tm 105 ° C, acid value 28 mgKOH / g) 90 parts Polyester resin (Mw: 80,000, Tm 143 ° C, acid value 20 mgKOH / g) 10 parts Carnauba wax (Melting point 79 ° C., volume average particle size 150 μm) 5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei Co.) 8 parts 3,5-di-tert-butyl iron salicylate 2 parts The mixture having the above composition is sufficiently stirred in a Henschel mixer. After carrying and mixing, roll mill at a temperature of 90 to 100 ° C for about 30
After heat-melting for 1 minute and cooling to room temperature, the obtained kneaded product γ is pulverized and classified by a jet mill and an air classifier, and 1.0 part of silica (R974 manufactured by Nippon Aerosil Co., Ltd.) is added to 100 parts of the toner base particles. And Titania (manufactured by Nippon Aerosil Co., Ltd., T805) were added, and after stirring and mixing with a Henschel mixer, large particles were removed through a mesh to obtain Toner 5. Dynamic friction coefficient 0.32, circularity 0.92, loose apparent density 0.35 g / cm ³ , cohesion 31%, wax average dispersion diameter 0.3 μm

Example 6 Toner 6: Toner 6 was obtained in the same manner as Toner 1, except that a mechanical mill turbo mill was used instead of the jet mill in Toner 1. Dynamic friction coefficient 0.28, circularity 0.94, loose apparent density 0.40 g / cm ³ , cohesion 30%, wax average dispersion diameter 1.4 μm

(Example 7) Toner 7: In Toner 1, the additive was formulated such that 1.0 part of silica (R974, manufactured by Nippon Aerosil Co., Ltd.) and alumina (RFY-C;
Toner 7 was obtained in the same manner as Toner 1, except that 0.5 part was added. Dynamic friction coefficient 0.28, circularity 0.91, loose apparent density 0.38
g / cm ³ , aggregation degree 31%, wax average dispersion diameter 1.4
μm

(Example 8) Toner 8 Toner 1, the additive was formulated such that 2.0 parts of silica (R974, manufactured by Nippon Aerosil Co., Ltd.) and titania (T805, manufactured by Nippon Aerosil Co., Ltd.) were used per 100 parts of toner base particles. Toner 8 was obtained in the same manner as Toner 1 except that 0.5 part was added. Dynamic friction coefficient 0.2
8, roundness 0.91, loose apparent density 0.36g / c
m ³ , cohesion 25%, wax average dispersion diameter 1.4 μm

(Example 9) Toner 9: Polyester resin (Mw: 6000, Tm 105 ° C, acid value 28 mgKOH / g) 90 parts Polyester resin (Mw: 80,000, Tm 143 ° C, acid value 20 mgKOH / g) 10 parts Carnauba wax (Melting point 79 ° C., volume average particle size 150 μm, spray dry manufacturing method) 3 parts Carbon black (# 44: manufactured by Mitsubishi Kasei) 8 parts 3,5-di-tert-butylsalicylic acid zinc salt 2 parts A mixture of the above composition After thoroughly stirring and mixing in a Henschel mixer, roll mill at a temperature of 90 to 100 ° C for about 30
After heat-melting for 1 minute and cooling to room temperature, the resulting kneaded product was pulverized and classified by a jet mill and an air classifier, and 1.0 part of silica (R976, manufactured by Nippon Aerosil Co., Ltd.) was used for 100 parts of the toner base particles. Then, 0.5 part of titania (T805, manufactured by Nippon Aerosil Co., Ltd.) was added, and the mixture was stirred and mixed with a Henschel mixer, and then large-sized particles were removed through a mesh to obtain Toner 9. Dynamic friction coefficient 0.39, circularity 0.92,
Loose apparent density 0.37 g / cm ³ , aggregation degree 28%,
Wax average dispersion diameter 0.3 μm

(Example 10) Toner 10: Toner 1 was prepared by adding 100 parts of toner base particles to silicone oil-treated silica (R976 is dimethyl silicone oil-treated product) per 100 parts of toner base particles.
0 parts and titania (T805, manufactured by Nippon Aerosil Co., Ltd.)
Toner 10 was obtained in the same manner as Toner 1, except that 0.5 part was added. Dynamic friction coefficient 0.30, circularity 0.
91, loose apparent density 0.41 g / cm ³ , cohesion degree 3
4%, wax average dispersion diameter 1.4 μm

[0057] (Example 11)   Toner 11:     Polyester resin (Mw: 6000,       Tm105 ° C, acid value 28mgKOH / g) 90 parts     Polyester resin (Mw: 80,000,       Tm 143 ° C., acid value 20 mg KOH / g) 10 parts     Carnauba wax (melting point 82 ° C, volume average particle size 580 μm) 3 parts     8 parts of carbon black (# 44: Mitsubishi Kasei)     Zirconium salt of 3,5-di-t-butylsalicylic acid 1 part

The mixture having the above composition was sufficiently agitated and mixed in a Henschel mixer, heated and melted at a temperature of 90 to 100 ° C. for about 30 minutes by a roll mill, and cooled to room temperature. After pulverizing and classifying with a classifier, 1.0 part of silica (R974 manufactured by Nippon Aerosil Co., Ltd.) and 0.5 part of titania (manufactured by T805 Nippon Aerosil Co., Ltd.) are added to 100 parts of toner, stirred and mixed with a Henschel mixer, and then passed through a mesh. Toner 1 with large particles removed
Got 1. Dynamic friction coefficient 0.27, circularity 0.92, loose apparent density 0.33 g / cm ³ , cohesion 32%, wax average dispersion diameter 1.3 μm

(Embodiment 12) Toner 12: Toner 9 has a heating and melting temperature of 80 to 80.
Toner 12 was obtained in the same manner as Toner 9 except that the temperature was changed to 90 ° C. Dynamic friction coefficient 0.44, circularity 0.91, loose apparent density 0.37 g / cm ³ , cohesion 29%, wax average dispersion diameter 1.0 μm

Example 13 Toner 13: A monomer composition uniformly dissolved or dispersed according to the following formulation was suspension polymerized in a dispersion medium system in which a suspension stabilizer was dispersed in water. . To 100 parts of the obtained polymer particles, silica (R974, manufactured by Nippon Aerosil Co., Ltd.) was added.
0 parts and titania (T805, manufactured by Nippon Aerosil Co., Ltd.)
0.5 part was added, and after stirring and mixing with a Henschel mixer, large particles were removed through a mesh, and Toner 13 was obtained. Dynamic friction coefficient 0.44, circularity 0.98, loose apparent density 0.49 g / cm ³ , cohesion 8%, wax average dispersion diameter 0.3 μm

[0061] [Black toner prescription]     Styrene 150 parts     Butyl acrylate 50 parts     Chromium complex of di-tert-salicylic acid 2 parts     Initiator (V-601, Wako Pure Chemical Industries, Ltd.) 10 parts     Paraffin wax (melting point 155 ° F, manufactured by Nippon Seiro Co., Ltd.) 5 parts     20 parts of carbon black (Regal 400R, manufactured by Cabot)     Aluminum [AL-M, Ajinomoto Co.] 0.6 part

Example 14 The experiment machine was set to the developing conditions shown in Table 2, and Toner 1 was set in the experiment machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

(Example 15) The experiment machine was set to the developing conditions shown in Table 2, and Toner 2 was set in the experiment machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

Comparative Example 1 The experimental machine was set to the developing conditions shown in Table 2, and Toner 3 was set in the experimental machine to obtain 300
A durability test of K sheets was carried out. The results are shown in Table 2.

(Example 16) The experiment machine was set to the developing conditions shown in Table 2, and Toner 4 was set in the experiment machine to obtain 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

Example 17 The experiment machine was set to the developing conditions shown in Table 2, the toner 5 was set in the experiment machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

Example 18 The experiment machine was set to the developing conditions shown in Table 2, the toner 6 was set in the experiment machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

(Example 19) The experimental machine was set to the developing conditions shown in Table 2, and Toner 7 was set in the experimental machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

Example 20 The experimental machine was set to the developing conditions shown in Table 2, the toner 8 was set in the experimental machine, and 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

(Example 21) The experiment machine was set to the developing conditions shown in Table 2, and Toner 9 was set in the experiment machine to obtain 30
A durability test of 0K sheets was performed. The results are shown in Table 2.

Example 22 The experimental machine was set to the developing conditions shown in Table 2, the toner 10 was set in the experimental machine, and 3
A durability test of 00K sheets was carried out. The results are shown in Table 2.

(Example 23) The experimental machine was set to the developing conditions shown in Table 2, the toner 11 was set in the experimental machine, and 3
A durability test of 00K sheets was carried out. The results are shown in Table 2.

(Example 24) The experimental machine was set to the developing conditions shown in Table 2, the toner 12 was set in the experimental machine, and 3
A durability test of 00K sheets was carried out. The results are shown in Table 2.

(Example 25) On the surface of the developing roller 15,
Spray the following mixed solution to give a coat thickness of 0.3 μm.
Adjusted to. Silicone resin (trade name: SR2410, manufactured by Toray Dow Corning Silicone Co., Ltd.) 600 parts Toluene 400 parts Aminosilane (trade name: SH6020, manufactured by Toray Dow Corning Silicone Co., Ltd.) 10 parts Titanium oxide fine powder 12 parts The developing roller Was assembled in the apparatus of FIG. This experimental modified machine was set to the developing conditions shown in Table 2, Toner 1 was set in the experimental modified machine, and a durability test of 300K sheets was carried out. The results are shown in Table 2.

(Example 26) The experimental machine (before modification) was set to the developing conditions shown in Table 2, the toner 13 was set in the experimental machine (before modification), and the durability test of 300K sheets was carried out. . The results are shown in Table 2.

[Table 2] * Soil pollution rank: 1-10 grade evaluation. Rank 6 or higher is an acceptable level. Rank 10 is a state where there is no background stain. * Development roller contamination degree: After the completion of evaluation of 300K sheets, the development roller was removed and only the toner was blown off from the development roller. The degree of coloring on the surface of the developing roller thus obtained was measured with a Macbeth densitometer.

As is clear from Table 2, according to the present invention, the developing roller has very little stain, and the obtained image has little background stain and high density.

[0077]

INDUSTRIAL APPLICABILITY The present invention is a toner for a one-component developer which is resistant to heat stress and mechanical stress on the toner and can obtain a stable image, an oilless fixing electrophotographic image forming method and image formation using the toner. Equipment could be provided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an oilless fixing electrophotographic image forming apparatus.

[Explanation of symbols]

1 photosensitive drum 10 Imaging device 11 Insulating one-component developer containing no carrier particles 11a developer layer 12 Development container 13 Development area 14 Non-magnetic developing roller 15 Developing roller 16 elastic blade 20 electrostatic latent image forming means 30 transfer means 40 cleaning 50 bias power supply

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 5/56 C08K 5/56 C08L 91/06 C08L 91/06 101/00 101/00 G03G 9/087 G03G 15/00 9/097 303 15/00 15/08 501D 303 501Z 15/08 501 504A 506A 504 507L 506 9/08 384 507 346 (72) Inventor Fumihiro Sasaki 1-3-6 Nakamagome, Ota-ku, Tokyo F-Term (Reference) in Ricoh Co., Ltd. AF02W AG00W BB03W BB12W BC03W BC04W BC05W BC06W BC07W BC09W BC11W BD03W BE06W CC03W CD00W CE00W CF00W CJ00 W CK02W DA037 DE076 DE096 DE106 DE116 DE136 DE146 DE186 DE236 DJ006 DJ016 DJ036 DJ056 EZ008 FA086 FD016 FD097 GS00

Claims (21)

[Claims] 1. A dynamic friction coefficient in which wax is dispersed is 0.2.
Using a one-component developer consisting of toner of 0 to 0.45 and an electrophotographic image forming apparatus for oilless fixing, the developing roller speed of the apparatus is 25 to 85 cm / sec, and the contact pressure by the frictional charge imparting member is set. Is 30 g / cm or more, and the developer passing amount after passing through the triboelectrification imparting member is 0.02.
An image forming method comprising developing at 0.12 g / (cm · sec). 2. A developer after the developing roller speed of the oilless fixing electrophotographic image forming apparatus is 25 to 85 cm / sec, the contact pressure by the frictional charge imparting member is 30 g / cm or more, and the frictional charge imparting member is passed. Passing amount is 0.02-0.1
A one-component developer comprising a toner having a dynamic friction coefficient of 0.20 to 0.45 in which wax is dispersed, which is used under a developing condition of 2 g / (cm · sec). 3. The one-component developer according to claim 2, wherein rice wax and / or ester wax is used as the wax dispersed in the toner. 4. The raw material particle diameter of the wax used in the toner is 100 to 300 μm.
Alternatively, the one-component developer described in 3. 5. The one-component developer according to claim 2, wherein the wax is obtained by a spray-dry manufacturing method. 6. The wax dispersed in the toner has an average dispersion diameter of 0.1 to 0.8 μm, which is 2 to 5
The one-component developer according to any one of 1. 7. The one-component developer according to claim 2, wherein the toner has a circularity of 0.94 or more. 8. The one-component developer according to claim 2, wherein the loose apparent density of the toner is 0.3 or more. 9. The one-component developer according to claim 2, wherein the toner has an aggregation degree of 30% or less. 10. The one-component developer according to claim 2, wherein inorganic fine particles are present on the toner surface. 11. The one-component developer according to claim 2, wherein a silicone oil component is present on the toner surface. 12. A one-component developer according to claim 11, wherein the silicone oil component is based on an inorganic fine powder surface treatment agent. 13. The toner is a negative triboelectrifying toner having at least a binder resin, a colorant, a wax and an organometallic compound, wherein the organometallic compound is zirconium, an aromatic diol, an aromatic hydroxycarboxylic acid, and an aromatic compound. 3. The negative triboelectrifying compound according to claim 2, wherein the organozirconium compound is coordinated and / or bonded with an aromatic compound selected from the group consisting of a monocarboxylic acid and an aromatic polycarboxylic acid. toner. 14. The one-component developer according to claim 2, wherein the toner is granulated by a polymerization method. 15. An image forming apparatus equipped with the one-component developer according to claim 2. 16. The image forming apparatus according to claim 15, wherein the developing roller is covered with a silicone resin. 17. The image forming apparatus according to claim 16, wherein the silicone resin contains fine metal oxide powder. 18. The image forming apparatus according to claim 16, wherein the silicone resin contains an aminosilane coupling agent. 19. The development gap is 0.05 to 0.2 mm.
The image forming apparatus according to any one of claims 15 to 18, wherein 20. The image density control method is a method of controlling the image density by detecting the density of the toner adhered on the photoconductor and controlling the developing bias. 20. The image forming apparatus according to any one of 1 to 19. 21. The image forming apparatus according to claim 15, wherein an AC component is present in the developing bias.