HK1086353B - Toner, fixer and image forming apparatus - Google Patents

Description

Toner, fuser, and image forming apparatus

Technical Field

The present invention relates to a toner and a fixer (fixer) for developing an electrostatic latent image in electrophotography, electrophotographic recording, and electrophotographic printing, and an image forming apparatus using the toner.

Background

In the electrophotographic image forming method, a toner image is fixed onto a recording medium by passing the recording medium through a surface of a heating roller having a strippability to a toner while contacting the toner image under application of pressure, based on a heating method in which pressure is applied with the heating roller. This method has very good thermal efficiency in fusing the toner image to the recording medium because the toner image and the surface of the heating roller are in contact with each other under applied pressure, and the toner image can be fixed thereto quickly.

However, since the melted toner image is brought into contact with the heating roller under pressure, part of the toner image adheres to and transfers to the surface of the heating roller, causing a shift problem in which the adhered and transferred part of the toner image transfers again to the recording medium and contaminates the recording medium again. The offset problem is largely affected by the fixing speed and temperature.

In general, when the fixing speed is low, the surface of the heating roller has a relatively low temperature so that the amount of heat from the heating roller applied to the toner is constant regardless of the fixing speed.

In particular, in an electrophotographic full-color image forming method, a temperature difference between an uppermost layer contacting a heating roller and a lowermost layer contacting a recording medium, on which plural kinds of toners are to be laminated, becomes large when a fixing speed is high and a surface of the heating roller has a high temperature. The uppermost toner tends to have thermal offset problems. In contrast, when the heating roller has a low temperature in order to prevent the offset problem, the toner of the lowermost layer is not completely melted, resulting in a cold offset problem in which the toner is not fixed onto the recording medium and adheres to the heating roller.

There has recently been a demand for toners having a wide range of fixable temperatures usable even when the fixing speed is high or low and having good offset resistance.

On the other hand, a high-definition image with good fine line reproducibility is required. Therefore, the toner has a smaller particle diameter to improve image resolution and definition. However, the toner having a smaller particle diameter has a low fixing performance for an intermediate color image particularly when the fixing speed is high. This is because the amount of adhesion of the toner in the halftone image is small, and the toner transferred onto the concave surface of the recording medium receives less heat from the heating roller and less pressure because its convexity prevents the pressure applied to the concave surface. Further, the toner transferred onto the concave surface of the intermediate color image on the recording medium has a thin layer, and the pressure applied to the toner sheet is higher than that applied to the solid image having a thick toner layer, resulting in the occurrence of offset problems and a low-quality fixed image.

In order to produce a toner having both fixing performance and offset resistance, studies have been made on binder resins therein. Japanese patent laid-open No.5-107803 discloses a resin composition having a resin content of 10³To 7x10⁴And 10⁵To 2x10⁶A molecular weight distribution (measured by Gel Permeation Chromatography (GPC)) having at least one peak in each range.

Japanese patent laid-open Nos. 5-289399 and 5-313413 disclose methods of specifying the molecular weight of a vinyl copolymer and including a release agent such as polyethylene to impart both fixing performance and offset resistance to a toner. Japanese patent laid-open No.5-297630 discloses a method of improving the low-temperature fixability and hot offset resistance of a toner.

Japanese patent laid-open Nos. 5-053372, 6-027733, 6-075426, and 6-118702 disclose a method of widening the molecular weight of the binder resin and balancing the storage stability, fixability, and hot offset resistance of the resulting toner.

Japanese patent laid-open No.2002-372804 discloses a method of specifying the storage modulus of a toner so as to have good low-temperature fixing properties and offset resistance properties.

A conventional electrophotographic image forming apparatus includes a fixer in which pressure is applied to a heating roller including a heat source, and a recording medium on which toner is transferred passes therebetween to fix an image.

The fixing device sometimes has a shift problem in which toner on the recording medium adheres to the heating roller. The offset toner also adheres to the pressure roller and contaminates the recording medium when transferred therefrom. To prevent offset, the surface of the heating roller in the conventional fuser has been fluorinated. However, it is difficult to completely prevent the deviation due to environmental conditions and the kind of recording medium.

Some conventional fixing devices have a cleaner such as a cleaning roller that removes toner adhering to a heating roller and a pressure roller when in contact therewith. These cleaning members formed of pure metal are pressed against a heating roller and a pressure roller having improved surface peeling properties to remove toner with different surface peeling properties therebetween.

In recent years, the image forming apparatus stops supplying power to the heat source in a standby state, and does not supply power to the heating roller to have a fixable temperature until an image is formed. Therefore, it is required to improve the temperature responsiveness of the heating roller, for example, the heating roller has a thickness of 1mm to shorten the heating time to about 10 seconds to have a fixable temperature.

In this image forming apparatus, the heating roller has a small heat capacity, and has an uneven temperature distribution in the direction across the width because heat is transferred to the recording medium or an element in contact therewith and wind flows around the heating roller when fixing. In addition, the heating roller cannot have a uniform temperature on all surfaces thereof in consideration of space and cost.

When the heat roller has an uneven temperature distribution across the width direction, its fixing performance becomes unstable and offset tends to occur, and the heat roller has a shorter life due to heat aging. In Japanese patent laid-open Nos. 11-305577, 11-149180 and 2000-292981, agglomerated polymerized toner adhering to and accumulating on the cleaning member is again melted and transferred onto the recording medium to contaminate the recording medium. This is because the polymerization regulating agent having a low storage modulus adheres to the cleaning member, while the pulverized toner having a high storage modulus, which is difficult to melt, adheres thereto.

A recording medium having a very small size is more problematic than a recording medium having a maximum passable size. This is because the area where the small-sized recording medium contacts the heating roller is small, only the temperature of the small area is lowered, and the temperature sensor turns on the heat source, which unnecessarily raises the temperature of the area where the recording medium does not pass, thus causing the toner to melt on the cleaning member that cleans the area where the recording medium does not pass.

Japanese patent laid-open No.9-325550 discloses a fixing device that prevents an excessive increase in temperature of an area through which a recording medium does not pass, by blowing air to the fixing device to make the temperature distribution thereof uniform across the width direction.

Japanese patent laid-open No.9-325550 also discloses a fuser having a fan along a cleaning roller with which air is circulated to prevent the cleaning roller from having an excessively high temperature.

For these reasons, there is a need for a fuser that prevents toner from melting out of it and contaminating the image.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a fixer that prevents toner from being melted out therefrom and prevents a contaminated image, and an image forming apparatus using the same and toner used therein.

Another object of the present invention is to provide a fixer that prevents toner adhered to a cleaning member from being transferred onto a recording medium without reducing fixing performance, and an image forming apparatus using the same and toner used therein.

It is still another object of the present invention to provide a fuser that produces images with high image density and high definition, and an image forming apparatus using the fuser and a toner used therein.

These objects of the present invention, either individually or collectively, have been satisfied by the discovery that a fuser for fixing a toner including a binder resin and a colorant onto a recording medium by applying at least one of heat and pressure, the fuser including

A fixing member that fixes the toner onto a recording medium;

a pressing member that presses the toner thereon; and

a cleaning member for collecting toner from a fixing member or a pressing member onto a cleaning member,

wherein the storage modulus of the toner collected on the cleaning member is larger than that before fixing thereof.

These and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments of the invention, which is to be read in connection with the accompanying drawings.

Drawings

Various other objects, features and attendant advantages of the present invention will also be more readily appreciated as the same becomes better understood by reference to the following description when considered in connection with the accompanying drawings in which like reference characters designate like parts throughout the figures thereof and wherein:

FIG. 1 is a schematic view illustrating one embodiment of a fixer including a heating roller and a pressure roller of the present invention;

FIG. 2 is a schematic diagram illustrating one embodiment of a fuser including the fusing belt of the present invention;

FIG. 3 is a cross-sectional view illustrating one embodiment of the layer composition of the cleaning roller of the present invention;

FIGS. 4A and 4B are schematic diagrams for explaining the shapes of toners for shape factors SF-1 and SF-2;

fig. 5A to 5C are schematic views illustrating embodiments of the shape of the toner used in the present invention; and

fig. 6 is a schematic view illustrating an embodiment of an image forming apparatus of the present invention.

Detailed Description

The present invention provides a fixer and an image forming apparatus in which offset toner in the fixer is collected by a cleaning roller to prevent toner from melting out without limiting the design of the toner such as chargeability (amount of charge control agent) and fixability (amount of low molecular weight resin).

FIG. 1 is a schematic view illustrating one embodiment of a fixer including a heating roller and a pressing roller of the present invention.

The fixer 25 of the present invention includes a fixing roller (fixing roller)251 including a metal shaft formed of a metal such as stainless steel and aluminum; and an annular elastic layer covering the metal shaft, which is formed of a heat-resistant elastic material such as foam silicone rubber and liquid silicone rubber, thereby forming a nip with the pressing roller 252. The elastic layer includes a release layer on a surface thereof to improve the release properties of the transfer paper and the toner. The release layer is formed of a heat-resistant material having low surface energy such as a silicone resin, a fluorine-containing resin, and a polymer resin such as Polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). A heat source such as a halogen heater is provided in the metal shaft of the fixing roller 251 to accelerate the temperature rise thereof.

The pressing roller 252 includes a metal shaft formed of a metal such as stainless steel and aluminum; and an elastic layer of a suitable thickness covering the metal shaft, which is formed of a heat-resistant elastic material such as fluorine-containing rubber and silicone rubber. The elastic layer includes a release layer formed of a fluorine resin or the like on the surface thereof, as with the elastic layer of the fixing roller 251. The pressure roller 252 presses the fixing roller 251 by a pressing means such as a spring (not shown), and the elastic layer is elastically deformed to thereby form a nip, which presses and heats the toner therebetween for a prescribed time.

A coating roller 255 that coats oil such as silicone oil on the fixing roller 251 is provided to improve its peeling property against offset, and a cleaning roller 256 that removes toner and paper powder adhering to the fixing roller 251. A cleaning roller 257 is also provided to remove the toner from the fixing roller 251 and paper powder adhering to the pressure roller 252. Further, a temperature sensor 258 such as a thermistor detects the temperature of the fixing roller 251 or the pressing roller 252 to control a heater therein.

Fig. 2 is a schematic view illustrating an embodiment of a fuser including the fixing belt of the present invention. The fixing device 26 includes a heating roller 263, a fixing roller 261, a pressure roller 262 pressing the fixing roller 261, and a fixing belt 264 suspended between the heating roller 263 and the fixing roller 261.

Each of the fixing roller 261 and the pressing roller 262 includes a metal shaft formed of metal; and an elastic layer formed of a heat-resistant elastic material having a suitable thickness to cover the metal shaft. The elastic layer includes a peeling layer formed of a fluorine-containing resin on the surface thereof, as with the elastic layers of the fixing roller 251 and the pressing roller 252 in fig. 1. Each metal shaft includes a halogen heater. The pressure roller 262 presses the fixing roller 261 via the fixing belt 264 by a pressing means such as a spring (not shown), and the elastic layer is elastically deformed, thereby forming a nip, during which the toner is pressed and heated for a prescribed time.

The fixing belt 264 includes an endless belt base formed of a heat-resistant resin or metal. The heat-resistant resin includes polyimide, polyamideimide, polyetherketone, and the like. Metals include nickel, aluminum, stainless steel, and the like. The resin and the metal may be combined, and a belt formed of a polyimide resin on which nickel is electroformed is particularly preferably used because it has moderate strength, elasticity, and durability. The tape preferably has a thickness of not more than 100 μm. The fixing belt 264 includes an elastic layer formed of silicone rubber or the like, and a heat-resistant release layer formed of a fluorine-containing resin having a low friction coefficient when the transfer paper is brought into contact with the toner under application of pressure.

The heating roller 263 suspends and heats the fixing belt 264. Accordingly, the heating roller 263 includes a heat source such as a halogen lamp and a nichrome wire. The heating roller 263 is a thin-walled roller formed of a hollow metal cylinder made of aluminum, carbon steel, stainless steel, or the like, and an aluminum cylinder having a thickness of 1 to 4mm and good heat conductivity can have a narrow temperature distribution in its axial direction. Further, the surface of the heating roller 263 is coated with alunite to prevent abrasion of the fixed belt 264. A temperature sensor 268 formed of a thermocouple, a thermistor, or the like is provided along the circumference of the heating roller 263 passing through the fixing belt 264 to detect the temperature thereof. A temperature controller (not shown) controls the operation of the heater in the heating roller 263 according to a signal detected by the temperature sensor 268.

In fig. 1, the toner on the recording paper receives heat and pressure at a nip between a fixing roller 251 and a pressing roller 252 in the fixing device 25. Then, the toner melts, and its viscosity and elasticity decrease. At the same time, the toner expands on the recording paper with pressure and enters the fibers thereof. The recording paper then exits the nip and exits rollers 251 and 252. The low molecular weight component having a low viscosity included in the toner melts and easily penetrates into the fibers of the recording paper, and at the same time, easily separates from and adheres to the fixing roller 251 having a low elasticity. The polymer component having high viscosity and high elasticity is melted and transferred to the fixing roller 251 with its viscosity (adhesion property to the fixing roller 251) higher than that of elasticity. When the fixing roller 25 rotates and contacts another recording sheet, the transferred toner adheres thereto to thereby contaminate an image thereon. To avoid this problem, a cleaning roller is disposed through the fixing roller 251, to which silicone oil is applied or a release agent is included in the toner so that the toner does not remain thereon. However, it is difficult to completely prevent toner from remaining thereon.

Further, part of the toner is transferred from the fixing roller 251 to the pressing roller 252 having a lower temperature. When the pressure roller 252 rotates and contacts another recording sheet, the toner transferred to the pressure roller 252 adheres to the back surface thereof, thus contaminating an image thereon. To avoid this problem, the cleaning roller 257 is disposed by the pressure roller 252. The cleaning roller 257 collects the toner transferred from the fixing roller 251. However, when the fuser 25 starts operating, the toner collected on the cleaning roller 257 is sometimes melted under heat and the cleaning roller 257 is transferred to the pressure roller 252, contaminating the back surface of the recording sheet at the nip. In particular, the low molecular weight component in the toner binder resin is more easily melted out than the polymer component therein because the storage modulus of the low molecular weight component is easily changed by heating.

The toner adhering to the pressure roller 252 is collected by the cleaning roller 257 at the nip therebetween. Therefore, the toner adhering to the fixing roller 251 is collected by the cleaning roller 257, and several grams of toner are collected when 150,000 images are produced. Since the conventional toner uses a resin having a relatively high glass transition temperature of about 60 ℃ and has a high viscosity when adhering to the cleaning roller 257, the toner is difficult to melt out even when the fixer 25 and the cleaning roller 257 have a high temperature in proportion to the number of images produced. However, the low molecular weight resin that melts at a relatively low temperature melts below the fixable temperature of the toner. Therefore, the toner collected on the cleaning roller 257 is melted out therefrom, and adheres to the pressing roller 252 or the fixing roller 251 again when the pressing roller 252 or the fixing roller 251 rotates without passing the recording paper therebetween. When the recording paper passes therebetween, the recording paper is contaminated by the melted-out toner.

The cleaning roller 257 in the fixer 25 is coated with an active material that increases the energy storage modulus of the binder resin. Therefore, the toner collected on the cleaning roller 257 does not adhere to the pressing roller 252 or the fixing roller 251 when the pressing roller 252 or the fixing roller 251 rotates without passing the recording paper therebetween. This is because the storage modulus of the toner collected on the cleaning roller is larger than that of the toner before passing through the fixer, and therefore it is difficult to adhere to the pressure roller 252 even when further heated.

Further, the cleaning roller 257 in the fixer 25 may have a coating layer including an active material that increases the viscoelasticity of the binder resin in the toner. FIG. 3 is a cross-sectional view illustrating one embodiment of the layer composition of the cleaning roller of the present invention. The coating layer 257b includes only an active material or an active material and a binder resin. The coating layer 257b including only the active material becomes brittle under mechanical stress and sometimes peels off from the metal shaft. In order to prevent the coating layer 257b from being peeled off from the metal shaft, at least one binder resin is preferably included therein.

In the fixing device of the present invention, the ratio dcore (active material/binder resin) at the contact portion between the coating 257b of the cleaning roller 257 and the metal shaft and the ratio dsurface (active material/binder resin) of the surface thereof satisfy the following relationship:

d core > D surface

Even when the toner collected on the cleaning roller 257 is hardened by the crosslinking reaction, the active material diffuses from the surface of the stem 257a having the ratio D core, thereby providing another reaction opportunity. Therefore, the above relationship must be satisfied.

In the fixer 25 of the present invention, the coating layer 257b may be multi-layered, for example, the coating layer 257 b' in fig. 3 includes a first coating layer 257b and a second coating layer 257 c. The toner collected by the cleaning roller 257 is accumulated as the second coating layer 257c, and thus the coating layer 257 b' has a plurality of layers each having a different content of the active material per unit volume, in which the concentration thereof is moderately changed. The toner collected by the cleaning roller 257 reacts with the active material to prevent the toner from being melted out therefrom. This is because the binder resin in the toner crosslinked with the active material has a higher elastic modulus to prevent the toner from melting out. Further, the content of the active material in the first coating layer 257b is high, and the content in the second coating layer 257c formed by accumulating the collected toner gradually decreases. When the second layer 257c has a lower active material concentration as the collected toner increases, the active material has no greater effect and the toner melts the toner.

The ratio (α/β) of the active material content (α) per unit volume in the first coating layer 257b to the active material content (β) per unit volume in the second coating layer 257c is 1 to 200.

When the ratio (α/β) is less than 1, the diffusion speed of the active material in the second coating layer 257c is lower than that of the first coating layer 257b, and the active material has a lower chance of reacting with the toner, resulting in difficulty in preventing the toner from melting out. When the ratio (α/β) is higher than 200, the active material is less added to the toner collected on the surface of the second coating layer 257c, and the active material also has a lower chance of reacting with the toner, resulting in difficulty in preventing the toner from melting out.

The collected toner adheres to the surface of the second coating layer 257c, and the second coating layer 257c is gradually grown together with the toner. Accordingly, the second coating layer 257c may not include a fixing content of the active material, and may have a gradient thereof in a range of the ratio (α/β)1 to 200. In particular, when the fixer is used for a long time, the boundary between the binder resin in the toner and the resin in the second coating layer 257c gradually becomes indefinite and integrated. The active material also diffuses into the binder resin of the toner collected on the surface thereof and increases the elastic modulus of the binder resin, thus preventing the toner from melting out. However, when the ratio (α/β) is higher than 200, the active material is added to the collected toner at a low speed and in a small amount, resulting in difficulty in preventing the toner from melting out. In addition, the second coating layer 257c preferably includes an active material in an amount of not less than 2% by weight. When the content is less than 2% by weight, the collected toner cannot be crosslinked to increase its elastic modulus, resulting in difficulty in preventing toner fusing.

The first coating layer 257b preferably includes the active material in an amount of 0.05 to 1.0g, more preferably 0.1 to 0.3 g. When the content is less than 0.05g, the amount of the active material added to the second coating layer 257c is too small to increase the viscoelasticity of the toner, and the life of the resulting cleaning roller is short. When the content is more than 1.0g, the first coating layer 257b is thick, and the total amount of the toner collected on the cleaning roller 257 becomes low, while the first coating layer 257b is hardened and has cracks.

The second coating layer 257c preferably includes an active material in an amount of not more than 10 g. When the content thereof is more than 10g, the second coating layer 257c is thick, and wherein the active material diffused from the first coating layer 257b takes too long to prevent the toner from melting out.

As described above, in a small image forming apparatus, the first coating layer 257b and the second coating layer 257c preferably include an appropriate amount of the active material, respectively.

The active material that increases the storage modulus includes a material that is crosslinked or extended with a binder resin to increase the molecular weight. It is preferable to use a material that increases the storage modulus by crosslinking with a functional group having polarity in the binder resin. The materials to which they are crosslinked are different from amines and ketones that are crosslinked or elongated with monomers in a solvent. Specific examples of the active material that increases the storage modulus include metal compounds such as metal salts of naphthenic acids or higher fatty acids; an azo metal complex; metal salicylate or zinc salicylate; metal complexes of chromium, iron, zirconium, etc.; and chelate compounds or metal alcoholates of silicon, zirconium or aluminum. These are applied to the cleaning roller 257, cross-linked with the toner collected thereon and increase the storage modulus thereof, thereby preventing the toner from again melting out of the cleaning roller 257 and contaminating the recording paper.

Specific examples of the coating resin include, but are not limited to, polyester resins, styrene-alkyl acrylate resins, styrene-alkyl methacrylate resins, styrene-butadiene resins, styrene-acrylonitrile resins, polyurethane resins, epoxy resins, silicone resins, polyvinyl chloride, polyamide resins, phenol resins, xylene resins, and the like. The resin preferably includes functional groups that react with the active material at the ends. Functional groups that react or interact with the active material include polar groups containing heteroatoms, such as carbonyl groups, carbamate groups, urea groups, sulfonic acid groups, and the like. The use of carboxylic acids which form polyester resins is particularly preferred. Carboxylic acids readily interact with active material hydrogen bonding. In addition, carboxylic acids can be relatively easily substituted with other functional groups because they are not strongly bonded thereto, and diffuse active species.

Specific examples of the solvent for coating the resin include aromatic hydrocarbons such as toluene and xylene; poly (meth) acrylates such as methyl ethyl ketone and alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol, ethoxyethanol, butoxyethanol, and the like; nitriles such as acetonitrile; and dioxane, and the like. Preference is given to using alcohols.

The active material and the resin are dissolved and mixed in a solvent to prepare a coating liquid. Specific examples of the coating method include, but are not limited to, roll coating, blade coating, brush coating, air spray coating, and the like.

The first coating layer 257b preferably includes an active material to resin amount ratio (active material/resin) of 30 to 70% by weight/70 to 30% by weight, more preferably 40 to 60% by weight/60 to 40% by weight.

When the active material is less than 30% by weight and the resin exceeds 70% by weight, the amount of the active material is too small to react with the toner collected by the cleaning roller 257 and increase its viscoelasticity. The thicker coating layer 257 b' may compensate for the amount thereof, but the cleaning roller 257 collects less toner, resulting in a disadvantage of miniaturization of the image forming apparatus. When the active material exceeds 70% by weight and the resin is less than 30% by weight, the coating layer 257 b' becomes small in adhesive force and is fragile and liable to have cracks by an external force.

The cleaning roller 257 in the fixer 25 of the present invention is formed of a metal such as copper (e.g., SUS, brass, etc.) and aluminum, and has a roller shape with a diameter of 10 to 30 mm. Further, the cleaning roller 257 has a ten-point average roughness Rz (hereinafter referred to as "roughness Rz") of 3 to 50 μm. The surface roughness Rz can be formed by a method such as a shot blast method, a sand blast method and a liquid grinding method, and the sand blast method is particularly preferably used because of its easiness. The shape of the roller has a wide area available in the circumferential direction, and the cleaning roller 257 has a long life. The cleaning roller 257 has a diameter as small as possible that can be installed in the fuser. When the cleaning roller 257 is too large in diameter, the fuser 25 has a long warm-up time. However, the large cleaning roller 257 has a large surface area, and can collect more toner. Further, the toner collected thereon has a thinner thickness and the variation in thickness is smaller, so that the mechanical pressure and heat to the pressure roller 252 are reduced, and the resulting fixer has good stability. When the cleaning roller 257 has a too small diameter, the toner collected thereon has a thick thickness, so that mechanical pressure and heat to the pressure roller 252 are increased, causing the toner to melt. The coating liquid including the active material may be uniformly coated on the cleaning roller 257 having a prescribed roughness Rz. When Rz is small, the coating liquid self-cleaning roller 257 falls. When too large, the active material cannot stay uniformly thereon. The pressure roller 252 may have a plurality of cleaning rollers 257. The cleaning roller 257 may be in a housing together with the fixing roller 251 or separately.

The fuser of the present invention includes a pressing device that presses the cleaning roller 257 to the pressing roller 252 or the fixing roller 251. The pressing means may be in the form of a roller or plate and may be a spring. The cleaning roller 257 is spring-pressed to the pressure roller 252 to more effectively collect the toner adhering thereto.

The pressing means is movable so that the cleaning roller 257 is pressed to the pressing roller 252 under a fixing pressure even when the cleaning roller 257 has a large diameter of the collected toner.

The toner of the present invention preferably has (1) a storage modulus of 5.0x10 at 120 ℃ before heating in a fixer³To 5.0x10⁴Pa, more preferably 1.0X 10⁴To 2.0x 10⁴Pa, and (2) storage modulus at 180 ℃ of 1.0X 10³To 3.0x 10⁴Pa, more preferably 1.5X 10³To 2.5x 10³Pa。

Toners having these storage moduli have good low-temperature fixability and hot offset resistance.

When the storage modulus is lower than this range, the hot offset resistance of the resulting toner is lowered. When it is higher than this range, its low-temperature fixability is lowered.

As described above, the toner of the present invention preferably includes a metal compound that crosslinks or elongates the prepolymer when heated. The metal compound preferably includes an organometallic compound serving as a charge control agent, i.e., a metal compound of an aromatic carboxylic acid derivative, and particularly preferably a salicylic acid metal compound is used. The metal preferably has a divalent or polyvalent valence, particularly preferably Al is used³⁺. When the toner includes the metal compound in an amount of 0.5 to 6.0% by weight, the toner has a low initial charge amount variation and easily has a desired absolute charge amount at the time of development. Therefore, the resulting image quality degradation, such as blurred images and low image density, can be prevented.

The storage modulus at 120 ℃ of the toner of the present invention when collected on the cleaning member is preferably 1 to 10 of the storage modulus at 120 ℃ before passing through the fuser²And (4) doubling. When less than 1 time, the toner adheres to the pressure roller 252 or the fixing roller 251 again. When greater than 10²At double, the low-temperature fixability of the resulting toner decreases.

Further, the storage modulus at 180 ℃ of the toner of the present invention when collected on the cleaning member is preferably 1 to 10 times the storage modulus at 180 ℃ before passing through the fixer. When less than 1 time, the toner adheres to the pressure roller 252 or the fixing roller 251 again. When more than 10 times, the low-temperature fixability of the resulting toner decreases.

The difference between the storage modulus G '1 at 120 ℃ before the active material is added thereto and the storage modulus G' 2 at 120 ℃ after the active material is added thereto of the toner of the present invention for the fuser 25 satisfies the following relationship:

0＜G’2-G’1≤10,000Pa

in addition to the fixing conditions of the fixer 25, the thermal properties of the toner also affect the toner fusing. In particular, its storage modulus largely affects its fixing and fusing. The larger the storage modulus, the faster the toner returns to normal even when deformed. Therefore, the large storage modulus can prevent toner offset and prevent toner from melting out when collected on the cleaning roller 257. However, when the storage modulus is too large, its minimum temperature at which fixing is possible deteriorates.

The difference between the storage modulus G 'of the toner at 120 ℃ before the active material is added thereto and the storage modulus G' at 120 ℃ after the active material is added thereto satisfies the following relationship:

0＜G’2-G’1

the storage modulus G' 1 of the toner at 120 ℃ before the active material is added thereto is preferably at least 5,000 to 20,000 Pa. In addition, the difference G '2-G' 1 is less than or equal to 10,000 Pa. The greater the storage modulus at 120 ℃ after addition of the active material to the toner, the stiffer the toner. The difference G '2-G' 1 ≦ 10,000Pa prevents the collected toner from damaging the surfaces of the pressing roller 252 and the fixing roller 251.

In the present invention, viscoelasticity is measured by RheoStress RS50 available from HAAKE GmbH under the following conditions: 1g of sample was fixed to the parallel plates at a frequency of 1Hz, a temperature of 80 to 210 ℃, a deformation of 0.1 and a temperature rise rate of 2.5 ℃/min.

The binder resin included in the toner of the present invention is preferably a polyester resin having an acid value of 1.0 to 50.0 KOHmg/g. This is because the polyester resin having an acid value of 1.0 to 50.0KOH mg/g is more effective in preventing the toner from adhering to the pressure roller 252 or the fixing roller 251 again. When the amount is less than 1.0KOH mg/g, such an effect cannot be produced. When more than 50.0KOH mg/g, the low-temperature fixability of the resulting toner decreases.

The content of the charge control agent depends on the kind of the binder resin used, whether or not an additive is added, and the toner manufacturing method (such as a dispersion method) used, and is not particularly limited. However, the content of the charge control agent is generally 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the binder resin included in the toner. When the content is too high, the toner has a large amount of electric charge, and thus the electrostatic force of the developing roller attracting the toner is increased, resulting in deterioration of the fluidity of the toner and the image density of the toner image.

The charge control agent and the release agent may be kneaded under heating together with the pigment master batch and the resin. Further, the charge control agent may be added to the toner component when dissolved or dispersed in an organic solvent, and is preferably fixed to the toner matrix.

The toner of the present invention comprising 0.5 to 6.0% by weight of a salicylic acid metal compound as a charge control agent has a low initial charge amount variation and easily has a desired absolute charge amount at the time of development. Accordingly, degradation of the resulting image quality, such as a blurred image and low image quality, can be prevented. When less than 0.5% by weight, thermal offset tends to occur and the resultant toner charge amount tends to vary. When more than 6.0% by weight, the low-temperature fixability of the resulting toner decreases.

The fuser of the present invention includes a feeder 259 that feeds an active material to the cleaning roller 257. The feeder 259 is preferably a feed roll that contacts the pressure roll 252. The feed roller 259 has a brush formed of resin fibers, and wipes off the compacts 260 of the active material with the brush and causes the active material to adhere to the pressing roller 252. Then, the active material adheres to the toner surface transferred from the heating roller to the pressure roller 252, and is collected together with the toner by the cleaning roller 257. The toner thus collected reacts with the active material and is cross-linked to have a higher storage modulus, and is firmly fixed to the cleaning roller 257. The toner having a higher storage modulus does not melt and adheres again to the pressure roller 252, thus contaminating the recording sheet.

The toner for the fixer of the present invention is prepared by a pulverization method and a polymerization method such as a suspension polymerization method, an emulsion dispersion polymerization method, an emulsion flocculation method and an emulsion association method, but the method is not limited thereto.

The pulverization method includes mixing a resin, a pigment or dye as a colorant, a charge control agent, and other additives with a mixer such as a HENSCHEL mixer to prepare a mixture; kneading the mixture with a heating kneader such as a batch type two-roll mill, a BUMBURY mixer, a continuous twin-shaft extruder and a continuous single-shaft extruder to prepare a kneaded mixture; spreading and cooling the kneaded mixture under an applied pressure to prepare a spread and cooled mixture; shearing and pulverizing the spread and cooled mixture to prepare a pulverized mixture; pulverizing the pulverized mixture with a pulverizer such as a jet mill and a mechanical pulverizer to thereby prepare a pulverized mixture; classifying the pulverized mixture by a classifier using a circulating air stream or Coanda effect, thereby producing particles having a prescribed particle diameter; and externally adding an inorganic particulate material to the particles having the prescribed size, thereby preparing a toner.

The polymerization process includes crosslinking and/or extending a toner component including a polymer having active hydrogen atoms, a polyester resin, a colorant, and a release agent in an aqueous medium in the presence of a particulate resin, thereby preparing a toner.

The toner used in the fuser of the present invention includes wax as a releasing agent. The state of presence of the wax in the toner greatly affects the releasing property thereof at the time of fixing, and when the wax is finely dispersed in the toner and is present in a large amount near the surface thereof, the toner has good releasing property. The wax is particularly preferably dispersed with its major axis not greater than 1 μm. When wax is present in the toner as described above, offset toner on the fixing roller 251 and toner collected by the cleaning roller 257 contacting the pressure roller are reduced.

Specific examples of the wax include known waxes such as polyolefin waxes, e.g., polyethylene wax and polypropylene wax; long chain hydrocarbons such as paraffin and sasol wax; and waxes including carbonyl groups. Among these waxes, waxes including a carbonyl group are preferably used, and specific examples thereof include polyester alkylates (polyester alkylates) such as carnauba wax, montan wax, trimethylolpropane behenate, pentaelislihol tetrabenate, pentaelislihol diacetylehenate, glycerol behenate, and 1, 18-octadecanediol distearate; polyalkanol esters such as tristearyl trimellitate and distearyl maleate; polyamide alkylates such as ethylenediamine behenamide; polyalkylamides such as tristearylamide trimellitate; and dialkyl ketones such as distearyl ketone. Among these waxes including carbonyl groups, polyester alkylate is preferably used. The waxes useful in the present invention generally have a melting point of from 40 to 160 deg.C, preferably from 50 to 120 deg.C, more preferably from 60 to 90 deg.C. Waxes having a melting point of less than 40 ℃ have an adverse effect on their high-temperature storage properties, and waxes having a melting point of more than 160 ℃ tend to cause cold offset of the resulting toner when fixed at low temperatures. Further, the wax has a melt viscosity of 5 to 1,000cp, more preferably 10 to 100cp, when measured at a temperature 20 ℃ higher than the melting point. The wax having a melt viscosity higher than 1,000cp makes it difficult to improve hot offset resistance and low-temperature fixability of the resultant toner. The content of the wax in the toner is preferably 0 to 40% by weight, more preferably 3 to 30% by weight.

The toner used in the fuser of the present invention includes a charge control agent. The charge control agent fixed to the surface of the toner can improve the charging performance of the toner. When the charge control agent is fixed onto the toner surface, the amount and state of its presence can be stabilized, and the charging performance of the toner can be stabilized accordingly. In particular, the toner of the present invention has good charging performance when a charge control agent is included.

Specific examples of the charge control agent include any known charge control agent such as nigrosine dyes, triphenylmethane dyes, metal complex dyes including chromium, chelate compounds of molybdic acid, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus and compounds including phosphorus, tungsten and compounds including tungsten, fluorine-containing activators, metal salts of salicylic acid, salicylic acid derivatives, and the like.

The content of the charge control agent depends on the kind of the binder resin used, regardless of whether an additive is added and the method of manufacturing the toner used (such as a dispersion method), and is not particularly limited. However, the content of the charge control agent is generally 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the binder resin included in the toner. When the content is too high, the toner has a large amount of electric charge, and thus the electrostatic force of the developing roller attracting the toner is increased, resulting in deterioration of the fluidity of the toner and the image density of the toner image. The charge control agent and the toner may be kneaded together with the pigment master batch and the resin under heating, or may be added to the toner components while being dissolved and dispersed in an organic solvent.

The toner used in the fuser of the present invention may have an average circularity of not less than 0.94. The toner having an average circularity of not less than 0.94 has good dot reproducibility and transferability. When the average circularity is less than 0.94 and away from the spherical shape, the resulting toner does not have sufficient transfer performance, and it is difficult to produce a high-definition image. The circularity of the toner is determined by dividing the circumference of a circle having an area equal to the area of the optically detected projected image by the actual circumference of the toner particles. Specifically, the circularity of the toner was measured by a flow-through particle image analyzer FPIA-2000 available from SYSMEX CORPORATION. The specific measurement method comprises adding 0.1-0.5 ml of surfactant (preferably alkylbenzene sulfonic acid) as dispersant, dispersing in 100-150 ml of water, wherein impurities in the water are removed in advance; adding 0.1-0.5g of toner to the mixture; dispersing the mixture including the toner with an ultrasonic disperser for 1 to 3 minutes, thereby preparing a dispersion liquid including a toner having a concentration of 3,000 to 10,000 pieces/. mu.l; and measuring the shape and distribution of the toner with the above-described measuring instrument.

The toner has an average volume particle diameter (Dv) of 3.0 to 8.0 μm, and a ratio (Dv/Dn) of the average volume particle diameter (Dv) to a number average particle diameter (Dn) thereof is 1.00 to 1.40. The toner having such particle diameter and particle diameter distribution has good thermal stability, low-temperature fixability and hot offset resistance, and particularly produces a full-color image having good gloss. Generally, the smaller the toner particle diameter, the more advantageous it is for producing high-resolution and high-quality images. However, transferability and cleanability of the toner are more disadvantageous. When the toner has an average volume particle diameter smaller than the range of the present invention, the toner is melt-adhered to the surface of the carrier in the two-component developer and reduces the chargeability of the carrier when stirred for a long time in the image developer. When used in a one-component developer, the toner tends to form on the charging roller, and the toner tends to fuse with elements such as blades to form a thin toner layer. The toner having a volume average particle diameter larger than the range of the particle diameter of the present invention causes difficulty in producing high-resolution and high-quality images, and at the same time, when the toner is consumed and added to a developer, the variation in particle diameter thereof becomes large in many cases.

When Dv/Dn is greater than 1.40, the charge amount distribution of the resulting toner becomes wide, and the image thus produced has low resolution. The average particle diameter and particle size distribution of the toner can be measured by a Coulter counter TA-II and a Coulter Multisizer II, available from Beckman Coulter, Inc. In the present invention, an interface (from Nikkaki biology co., Ltd.) and a personal computer PC9801 (from NEC Corp.) that produced the digital and volume distributions were connected to a Coulter Multisizer II to measure the average particle size and particle size distribution. The toner of the present invention preferably has a shape factor SF-1 of 100 to 180 and a shape factor SF-2 of 100 to 180.

Fig. 4A and 4B are schematic diagrams illustrating the shape of the toner for explaining the shape factors SF-1 and SF-2.

The shape factor SF-1 represents the circularity of the toner, and is determined according to the following formula (1):

SF-1＝{(MXLNG)²/AREA}x(100π/4) (1)

where MXLNG represents the absolute maximum length of the particle and AREA represents its projected AREA.

When SF-1 approaches 100, the shape of the toner approaches a sphere, and the toner comes into contact with other toners and photoreceptors at one point. Therefore, the toners rarely adhere to each other and have high fluidity. When SF-1 is greater than 180. The resulting toner has an amorphous form, and its developing property and transfer property are lowered.

SF-2 represents the shape unevenness of the toner, specifically, the square of the circumferential length (PERI) of the projected image AREA on the two-dimensional plane is divided by the image AREA (AREA) and multiplied by 100 π/4, so that SF-2 is determined as the following formula (2).

SF-2＝{(PERI)²/AREA}x(100π/4) (2)

When SF-2 is close to 100, the toner surface has low concavity and convexity and is smooth. The surface of the toner preferably has moderate unevenness, thereby having better cleaning performance. However, when SF-2 is more than 180, the unevenness is so conspicuous that the toner spreads on the resulting image.

The form factor was measured by photographing the toner with a scanning electron microscope (S-800) available from Hitachi, ltd. and analyzing the photographed image of the toner with an image analyzer Luzex III available from NIRECO corp.

The toner used in the fixer of the present invention has an almost spherical shape, which can be explained as follows.

Fig. 5A to 5C are schematic views illustrating the shape of the toner of the present invention. In FIGS. 5A to 5C, the minor axis r₂And the main shaft r₁Ratio of (r)₂/r₁) Preferably 0.5 to 1.0, thickness r₃And the minor axis (r)₂) Ratio of (r)₃/r₂) Preferably 0.7 to 1.0. When the ratio (r)₂/r₁) Below 0.5, the resulting toner far from the truly spherical shape has high cleanability, but is poor in dot reproducibility and transferability. When the ratio (r)₃/r₂) Below 0.7, the resulting toner in a nearly flat shape is not scattered as an amorphous toner, but does not have as high transferability as a spherical toner. Especially when the ratio (r)₃/r₂) At 1.0, the resultant toner becomes a rotary body having the main axis as the rotation axis, and its fluidity is improved. r is₁、r₂And r₃The measurement was performed by observing the toner with a Scanning Electron Microscope (SEM) and photographing the toner under changing the observation angle.

The toner used in the fixer of the present invention is preferably prepared by crosslinking and/or elongating a toner component in which at least a polymer capable of reacting with a compound having an active hydrogen atom, a polyester resin, and a colorant are dispersed in an organic solvent in an aqueous medium. The toner components and the method of preparing the toner will be explained below. The wet polymerization method will be explained, however, the toner may also be prepared by a dry melting and kneading method.

The modified polyester resin in the present invention includes polyester resins in which, in addition to monomer units containing alcohol and/or acid functionality, there are also monomer units having a functional group other than an acid or alcohol group that can form an ester bond; and a polyester resin in which a plurality of resin components having different structures are bonded to each other with covalent bonds, electrovalent bonds, or the like.

For example, a polyester resin having a functional group such as one or more isocyanate groups reactive with an acid group and/or a hydroxyl group at a terminal thereof, wherein the terminal is further modified or elongated with a compound including an active hydrogen atom, may be used. Further, a polyester resin having a terminal reactive with a compound including a plurality of hydrogen atoms, such as a urea-modified polyester resin or a urethane-modified polyester resin, may be used. Further, such polyester resins may be used: the polyester resin has reactive groups such as one or more double bonds in its backbone, which double bond free radical polymerization renders it to have a grafted component (i.e., carbon-to-carbon bonding), or wherein the double bonds are cross-linked with each other, such as a styrene-modified polyester resin or an acrylic-modified polyester resin.

It is also possible to use a polyester resin copolymerized in its main chain with a resin having a different composition or reacted with a resin having a different composition through a carboxyl group or a hydroxyl group at the terminal of the polyester resin, for example, a polyester resin copolymerized with a silicone resin having a terminal modified with a carboxyl group, a hydroxyl group, an epoxy group or a mercapto group, such as a silicone-modified polyester resin. Modified polyester resins are explained in more detail below.

724 parts of an adduct of bisphenol A with 2mol of ethylene oxide, 200 parts of isophthalic acid, 70 parts of fumaric acid and 2 parts of dibutyltin oxide were mixed and reacted in a reactor comprising a cooling tube, a stirrer and a nitrogen inlet tube at ordinary pressure and 230 ℃ for 8 hours. Then, after the mixture was decompressed to 10-15mm Hg (absolute pressure) and reacted for 5 hours, 32 parts of phthalic anhydride was added and reacted for 2 hours at 160 ℃. Next, 200 parts of styrene, 1 part of benzoyl peroxide and 0.5 part of dimethylaniline dissolved in ethyl acetate were reacted with the mixture at 80 ℃ for 2 hours, and the ethyl acetate was distilled and removed, thereby preparing a polystyrene graft-modified polyester resin having a weight average molecular weight of 92,000.

Specific examples of the urea-modified polyester resin (i) include a reaction product of a polyester prepolymer (a) having an isocyanate group and an amine (B). The polyester prepolymer (A) is formed by reacting a polyester having active hydrogen atoms, which is formed by polycondensation of a polyol (1) and a polycarboxylic acid (2), with a polyisocyanate (3). Specific examples of the group including an active hydrogen include a hydroxyl group (e.g., alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Particularly preferably, alcoholic hydroxyl groups are used.

As the polyol (1), there can be used a diol (1-1) and a polyol (1-2) having 3 or more valences, and it is preferred to use only (1-1) or a mixture of (1-1) with a small amount of (1-2). Specific examples of the diol (1-1) include alkylene glycols such as ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 4-butanediol and 1, 6-hexanediol; alkylene ether glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polybutylene ether hexanediol; alicyclic diols such as 1, 4-cyclohexanedimethanol and hydrogenated bisphenol A; bisphenols such as bisphenol a, bisphenol F and bisphenol S; adducts of the above alicyclic diols with alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide; and adducts of the above bisphenols with alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide. In particular, alkylene glycols having 2 to 12 carbon atoms and adducts of bisphenols with alkylene oxides are preferably used, and mixtures thereof are more preferably used. Specific examples of the polyhydric alcohol (1-2) having 3 or more valences include polyvalent aliphatic alcohols having 3 to 8 or more valences, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and sorbitol; phenols having 3 or more valences such as trisphenol PA, phenol novolac, cresol novolac; and adducts of the above polyphenols with 3 or more valences with alkylene oxides.

As the polycarboxylic acid (2), dicarboxylic acid (2-1) and polycarboxylic acid (2-2) having 3 or more valences can be used. It is preferred to use (2-1) alone, or a mixture of (2-1) with a small amount of (2-2). Specific examples of the dicarboxylic acid (2-1) include alkylene dicarboxylic acids such as succinic acid, adipic acid and sebacic acid; alkenylene dicarboxylic acids such as maleic acid and fumaric acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. Particular preference is given to using alkenylene dicarboxylic acids having from 4 to 20 carbon atoms and aromatic dicarboxylic acids having from 8 to 20 carbon atoms. Specific examples of the polycarboxylic acid (2-2) having 3 or more valences include aromatic polycarboxylic acids having 9 to 20 carbon atoms such as trimellitic acid and pyromellitic acid. The polycarboxylic acid (2) may be formed by reacting one or more polyols (1) with one or more anhydrides or lower alkyl esters of the above acids. Suitable preferred lower alkyl esters include, but are not limited to, methyl, ethyl and isopropyl esters.

The polyol (1) and the polycarboxylic acid (2) are mixed in such a manner that the equivalent ratio ([ OH ]/[ COOH ]) between the hydroxyl group [ OH ] and the carboxyl group [ COOH ] is generally from 2/1 to 1/1, preferably from 1.5/1 to 1/1, more preferably from 1.3/1 to 1.02/1.

Specific examples of the polyisocyanate (3) include aliphatic polyisocyanates such as butylene diisocyanate, hexylene diisocyanate and 2, 6-diisocyanate methylhexanoate; alicyclic polyisocyanates such as isophorone diisocyanate and cyclohexylmethane diisocyanate; aromatic diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate; aromatic aliphatic diisocyanates such as α, α, α ', α' -tetramethylxylylene diisocyanate; isocyanurates; the above polyisocyanates blocked with phenol derivatives, oximes and caprolactams; and combinations thereof.

The polyisocyanate (3) and the polyester are mixed in such a manner that the equivalent ratio ([ NCO ]/[ OH ]) between the isocyanate group [ NCO ] and the polyester having a hydroxyl group [ OH ] is generally from 5/1 to 1/1, preferably from 4/1 to 1.2/1, more preferably from 2.5/1 to 1.5/1. When [ NCO ]/[ OH ] is more than 5, the low-temperature fixability of the resulting toner decreases. When [ NCO ] has a molar ratio of less than 1, the urea content in the ester of the modified polyester decreases, and the heat offset resistance of the resulting toner decreases. The content of the constituent component in the polyester prepolymer (a) having a polyisocyanate group at the terminal thereof is 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. When the content is less than 0.5% by weight, the hot offset resistance of the resulting toner is lowered, and further, the heat resistance and low temperature fixability of the toner are also lowered. In contrast, when the content is more than 40% by weight, the low-temperature fixability of the resulting toner is reduced.

The number of isocyanate groups included in the molecule of the polyester prepolymer (a) is at least 1, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. When the amount of isocyanate groups is less than 1/molecule, the molecular weight of the modified polyester (i) decreases, and the hot offset resistance of the resulting toner decreases.

Specific examples of the amine (B) include diamine (B1), polyamine (B2) having three or more amino groups, aminoalcohol (B3), aminothiol (B4), amino acid (B5), and blocked amine (B6) in which the amino group in amines (B1) to (B5) is blocked. Specific examples of the diamine (B1) include aromatic diamines such as phenylenediamine, diethyltoluenediamine and 4, 4' -diaminodiphenylmethane; alicyclic diamines such as 4, 4 '-diamino-3, 3' -dimethyldicyclohexylmethane, diaminocyclohexane and isophoronediamine; aliphatic diamines such as ethylenediamine, butanediamine, hexamethylenediamine, and the like. Specific examples of the polyamine (B2) having three or more amino groups include diethylenetriamine, triethylenetetramine. Specific examples of aminoalcohols (B3) include ethanolamine and hydroxyethylaniline. Specific examples of the aminothiol (B4) include aminoethylthiol and aminopropylthiol. Specific examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Specific examples of the blocked amine (B6) include ketimine compounds prepared by reacting one of the amines (B1) to (B5) with ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; oxazoline compounds, and the like. Among these amines (B), diamines (B1) and mixtures in which diamines (B1) are mixed with a small amount of polyamine (B2) are preferably used.

If desired, the molecular weight of the modified polyester (i) may optionally be controlled with an elongation reaction catalyst. Specific examples of the elongation reaction catalyst control include monoamines such as diethylamine, dibutylamine, butylamine, and laurylamine; and blocked amines, i.e. ketimine compounds prepared by blocking the above monoamines.

The mixing ratio (i.e., the ratio [ NCO ]/[ NHx ]) of the content of the prepolymer (A) having an isocyanate group to the amine (B) is 1/2 to 2/1, preferably 1.5/1 to 1/1.5, more preferably 1.2/1 to 1/1.2. When the mixing ratio is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) decreases, resulting in a decrease in the hot offset resistance of the resulting toner. The modified polyester (i) may include a urethane bond as well as a urea bond. The molar ratio of urea linkages to urethane linkages (urea/urethane) is from 100/0 to 10/90, preferably from 80/20 to 20/80, more preferably from 60/40 to 30/70. When the content of the urea bond is less than 10%, the hot offset resistance of the resulting toner is lowered.

The improved polyesters of the invention have a major peak molecular weight of 1,000 to 10,000, preferably 2,000 to 8,000. When the component having a molecular weight of less than 1,000 is increased, the heat stability retaining property of the resulting toner is lowered. When the component having a molecular weight of more than 10,000 is increased, the low-temperature fixability of the resulting toner is decreased. Although depending on the toner components, the modified polyester includes 1 to 10% by weight, more preferably 3 to 6% by weight, of a polymer having a molecular weight of not less than 30,000. When the content is less than 1% by weight, the resulting toner does not have sufficient hot offset resistance, and when it is more than 10% by weight, the gloss and transparency of the resulting toner are sometimes reduced.

The toner including the polyester resin containing Tetrahydrofuran (THF) -insoluble matter in an amount of 1 to 25% by weight is further improved in hot offset resistance. Further, the toner improves image quality degradation caused by ultrafine toner particles generated by stress generated with a developing roller, a toner charging roller, a layer thickness regulating blade, and a triboelectric charging blade, and a fluidizing agent buried on the toner surface upon agitation in an image developer. However, the THF-insoluble matter adversely affects the gloss and transparency of the colored toner, and although the hot offset resistance thereof is improved, an amount of 1 to 10% by weight thereof sometimes works.

In the present invention, the unmodified polyester resin (ii) may be used in combination with the modified polyester resin (i) as the toner binder resin. The use of the modified polyester resin (ii) in combination with the modified polyester resin is more preferable than the use of the modified polyester resin alone because the low-temperature fixability and gloss of a full-color image of the resultant toner are improved. Specific examples of the unmodified polyester (ii) include polycondensation products of the polyol (1) and the polycarboxylic acid (2), which are similar to the modified polyester resin (i), and preferably used components similar to those used therefor. In view of the low-temperature fixability and hot offset resistance of the resulting toner, the modified polyester resin (i) and the unmodified polyester resin (ii) are preferably partially soluble in each other. Therefore, the modified polyester resin (i) and the unmodified polyester resin (ii) preferably have similar compositions. When the unmodified polyester resin (ii) is used in combination, the weight ratio ((i)/(ii)) of the modified polyester resin (i) to the unmodified polyester resin (ii) is from 5/95 to 80/20, preferably from 5/95 to 30/70, more preferably from 5/95 to 25/75, most preferably from 7/93 to 20/80. When the modified polyester resin (i) has a weight ratio of less than 5%, the resulting toner has poor hot offset resistance, and is difficult to have heat stable retainability and low temperature fixability.

The unmodified polyester resin (ii) preferably has a peak molecular weight of 1,000 to 20,000, preferably 1,500 to 10,000, more preferably 2,000 to 8,000. When less than 1,000, the heat stability retaining property of the resulting toner is lowered. When more than 10,000, its low-temperature fixability decreases. The unmodified polyester resin (ii) preferably has a hydroxyl value of not less than 5mg KOH/g, more preferably 10 to 120mg KOH/g, most preferably 20 to 80mg KOH/g. When less than 5, the resulting toner is difficult to have heat stable retaining property and low temperature fixability. The unmodified polyester resin (ii) preferably has an acid value of 10 to 30mg KOH/g, so that the resulting toner tends to be negatively charged and has better fixability. When more than 30mg KOH/g, the chargeability of the resulting toner is sometimes reduced, and an image having background dirt is produced particularly when used under high-humidity and high-temperature environments. .

In the present invention, the unmodified polyester resin (ii) preferably has a glass transition temperature (Tg) of 35 to 55 ℃, more preferably 40 to 55 ℃. The resulting toner can have heat-stable retention and low-temperature fixability. The dry toner including the unmodified polyester resin (ii) and the modified polyester resin (i) has better heat stable retention than the known polyester toner, despite the low glass transition temperature.

In the present invention, the toner binder resin has a storage modulus of 10,000dyne/cm²Preferably having a temperature (measured at a frequency of 20Hz (TG')) of not less than 100 deg.C, more preferably 110 to 200 deg.C. When less than 100 ℃, the hot offset resistance of the resulting toner decreases. The toner binder resin preferably has a temperature of not higher than 180 ℃, more preferably 90 to 160 ℃ at a viscosity of 1,000 poise (T η). When higher than 180 ℃, the low-temperature fixability of the resulting toner decreases. That is, TG' is preferably higher than T η in view of low-temperature fixability and hot offset resistance of the resulting toner. In other words, the difference between TG 'and T.eta. (TG' -T.eta.) is preferably not less than 0 ℃, more preferably not less than 10 ℃, still more preferably not less than 20 ℃. The maximum value of the difference is not particularly limited. In view of the heat-stable retaining property and low-temperature fixability of the resultant toner, the difference (TG '-T η) between TG' and T η is preferably 0 to 100 ℃, more preferably 10 to 90 ℃, most preferably 20 to 80 ℃.

As the releasing agent and the charge control agent, known releasing agents and charge control agents can be used as needed.

Inorganic particulate materials are preferably used as external additives. The inorganic particulate material preferably has a primary particle diameter of 5 μm to 2 μm, more preferably 5 μm to 500 μm. Further, the inorganic particulate material preferably has a specific surface area of 20 to 500m²In terms of/g (measured by the BET method). The toner of the present invention preferably includes 0.01 to 5.0% by weight, more preferably 0.01 to 2.0% by weight, of the inorganic particulate material. Specific preferred examples of suitable inorganic particulate materials include silica, titanium oxide, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, sand-lime, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like. In addition, polymer particle materials such as polystyrene formed by soap-free emulsion polymerization, suspension polymerization or dispersion polymerization, methacrylate or acrylate copolymers, silicone resins, benzoguanamine resins, condensation polymerization particles such as polymer particles of nylon and thermosetting resins may also be used.

The surface treatment agent can increase the hydrophobicity of these external additives and prevent the resulting toner from being lowered in fluidity and chargeability even under high humidity. Any desired surface treatment agent may be used depending on the nature of the treated particle of interest. Specific preferred examples of the surface treatment agent include silane coupling agents, silylation agents, silane coupling agents having an alkyl fluorine group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils.

The toner of the present invention further includes a cleaning performance improving agent for removing the developer remaining on the photoreceptor and the first transfer medium after transfer. Specific examples of the cleaning performance improving agent include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid; and polymer particles such as polymethyl methacrylate particles and polystyrene particles prepared by a soap-free emulsion polymerization method. The polymer particles have a rather narrow particle size distribution, preferably with a volume average particle size of 0.01 to 1 μm.

Specific examples of the colorant used in the present invention include any known dyes and pigments such as carbon black, nigrosine dyes, black iron oxide, naphthol yellow S, hansa yellow (10G, 5G and G), cadmium yellow, yellow iron oxide, loess, chrome yellow, titanium yellow, polyazo yellow, oil yellow, hansa yellow (GR, a, RN and R), pigment yellow L, benzidine yellow (G and GR), permanent yellow (NCG), sulfide fast yellow (5G and R), tartrazine lake, quinoline yellow lake, Anthrazane yellow BGL, isoindolinone yellow, red iron oxide, red lead, lead orange, cadmium red, mercury red, antimony, permanent red 4R, para-red, scarlet, para-chloro-ortho-nitroaniline red, lithofast scarlet G, brilliant fast scarlet, brilliant scarlet BS, permanent red (F2R, F4R, FRL and F4RH), fast red B, brilliant scarlet G, and brilliant scarlet G, Lithorubin GX, permanent red F5R, brilliant carmine 6B, pigment scarlet 3B, purplish red 5B, toluidine Maroon, permanent purplish red F2K, Helio purplish BL, purplish red 10B, BON Maroon Light, BON Maroon Medium, eosin lake, rhodamine lake B, rhodamine lake Y, alizarin lake, thioindigo B, thioindigo red, oil red, Maroon, pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perynone orange, oil orange, cobalt blue, cyan blue, basic blue lake, malachite blue lake, Victoria blue lake, metallo-free phthalocyanine blue, fast sky blue, indanthrene blue (RS and BC), indigo, ultramarine blue, anthraquinone blue, manganese violet B, methyl violet anthraquinone, cobalt lake, cobalt violet, zinc violet, chrome violet, zinc violet oxide green B, zinc violet green, zinc violet, zinc oxide, zinc violet, zinc oxide, zinc violet, Green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, lithopone, and the like. These materials may be used alone or in combination. The concentration of the colorant in the toner is preferably 1 to 15% by weight, more preferably 3 to 10% by weight, based on the total weight of the toner.

When combined with a resin, the colorant used in the present invention may be used in the form of a pigment masterbatch, if desired. Specific examples of resins for use in or in combination with the pigment masterbatch include the modified and unmodified polyester resins described above; styrene polymers and substituted styrene polymers such as polystyrene, poly (p-chlorostyrene), and polyvinyltoluene; styrene copolymers such as styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-alpha-chloromethyl methyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-ethylene-propylene copolymer, styrene-ethylene-butylene copolymer, styrene-ethylene-propylene copolymer, styrene-ethylene-butylene copolymer, Styrene-maleic acid copolymers and styrene-maleic acid ester copolymers; and other resins such as polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane resin, polyamide resin, polyvinyl butyral resin, acrylic resin, rosin, modified rosin, terpene resin, aliphatic or cycloaliphatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin and the like. These resins may be used alone or in combination. The master batch for the toner of the present invention is generally prepared by mixing and kneading the resin and the colorant under application of shear stress. In this case, the interaction of the colorant with the resin may be enhanced with an organic solvent. Further, a flush method in which an aqueous slurry including a colorant is mixed with an organic solvent of a resin to transfer the colorant to a resin solution, and then an aqueous liquid and the organic solvent are separated and removed may be preferably used, because the resulting wet cake of the colorant can be used as it is. Of course, a dry powder prepared by drying the wet cake may also be used as the colorant. In this case, a three-roll mill is preferably used to knead the mixture under the application of high shear stress.

The dry toner of the present invention can be prepared by, but is not limited to, the following method.

The aqueous medium may comprise water alone and a mixture of water and a solvent miscible with water. Specific examples of the solvent include alcohols such as methanol, isopropanol and ethylene glycol; dimethylformamide; tetrahydrofuran; cellosolves such as methyl cellosolve; and lower ketones such as acetone and methyl ethyl ketone.

For the method of stably producing a dispersion formed from the prepolymer (a) and the unmodified polyester resin (ii) in an aqueous medium, it is preferable to use a method comprising adding toner components formed from the prepolymer (a) and the unmodified polyester resin (ii) to an aqueous medium and dispersing them under application of shear stress. In preparing the dispersion, the prepolymer (a), the unmodified polyester resin (ii), and other toner components (hereinafter referred to as toner materials) such as a colorant, a pigment master batch, a release agent, a charge control agent, and the like may be added to the aqueous medium at the same time. However, it is preferred that the toner materials be premixed and then added to the aqueous medium. Furthermore, the method is simple. Other toner materials such as colorants, release agents, charge control agents, and the like, need not be added to the aqueous dispersion prior to forming the particles, and may be added after the particles are prepared in the aqueous medium. For example, the colorant may be added to the colorant-free particles by known dyeing methods after they have been formed.

The dispersion method is not particularly limited, and a low-speed shearing method, a high-speed shearing method, a rubbing method, a high-pressure jet method, an ultrasonic method, or the like can be used. Among these methods, the high-speed shearing method is preferably used because particles having a particle diameter of 2 to 20 μm can be easily prepared. At this time, the particle diameter (2 to 20 μm) means the particle diameter of the particles including the liquid. When a high-speed shear type disperser is used, the rotation speed is not particularly limited, but the rotation speed is usually 1,000 to 30,000rpm, preferably 5,000 to 20,000 rpm. The dispersing time is not particularly limited, but is usually 0.1 to 5 minutes. The temperature during dispersion is generally from 0 to 150 ℃ C (under pressure), preferably from 40 to 98 ℃. When the temperature is relatively high, the modified polyester (i) or the prepolymer (a) can be easily dispersed because the resulting dispersion has a low viscosity.

The content of the aqueous medium is usually 50 to 2,000 parts by weight, preferably 100 to 1,000 parts by weight, based on 100 parts by weight of the toner component comprising the prepolymer (a) and the unmodified polyester resin (ii). When the content is less than 50 parts by weight, the dispersion of the toner component in the aqueous medium is unsatisfactory, and thus the resulting mother toner particles do not have a desired particle diameter. In contrast, when the content is more than 2,000, the production cost is increased. It may be preferred to use a dispersant to prepare a stable dispersion comprising particles having a narrow particle size distribution.

The urea-modified polyester can be prepared from the prepolymer (A) by adding the amine (B) to the aqueous dispersion medium before or after the toner components are dispersed in the aqueous medium. The urea-modified polyester is preferably formed on the surface of the resultant toner, and may have a concentration gradient in the inside thereof.

Specific preferred examples of the dispersant for emulsifying and dispersing the oil phase in the aqueous medium in which the toner components have been dispersed include anionic surfactants such as alkylbenzenesulfonates, α -olefin sulfonates, and phosphates; cationic surfactants such as amine salts (e.g., alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives and imidazolines), and quaternary ammonium salts (e.g., alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, and benzethonium chloride); nonionic surfactants such as fatty acid amide derivatives, polyhydric alcohol derivatives; and amphoteric surfactants such as alanine, dodecylbis (aminoethyl) p-hydroxyphenylglycine, bis (octylaminoethyl) p-hydroxyphenylglycine and N-alkyl-N, N-dimethylammonium betaine. The surfactant having a fluoroalkyl group can produce a dispersion having good dispersibility even when a small amount of the surfactant is used. Specific examples of the anionic surfactant having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonylglutamate, sodium 3- { omega-fluoroalkyl (C6-C11) oxy } -1-alkyl (C3-C4) sulfonate, { omega-fluoroalkanoyl (C6-C8) -N-ethylamino } -1-propane sulfonate, sodium fluoroalkyl (C11-C20) carboxylic acid and metal salts thereof, perfluoroalkyl (C4-C12) sulfonic acid and metal salts thereof, perfluorooctylsulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfoneamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -salt of N-ethylsulfonyl p-hydroxyphenylglycine, And (C) a monoperfluoroalkyl (C6-C16) ethyl phosphate.

Specific examples of commercially available products of these surfactants having a fluoroalkyl group include SURLONS-111, S-112 and S-113, manufactured by Asahi Glass Co., Ltd.; FRORARD FC-93, FC-95, FC-98 and FC-129, manufactured by Sumitomo 3M Ltd.; UNIDYNE DS-101 and DS-102, manufactured by Daikin Industries, Ltd.; MEGAFACE F-110, F-120, F-113, F-191, F-812, and F-833, manufactured by Dainippon Ink and Chemicals, Inc.; ect EF-102, 103, 104, 105, 112, 123A, 306A, 501, 201, and 204, manufactured by Tohchem Products co., ltd.; FUTARGENT F-100 and F150, manufactured by Neos, etc.

Specific examples of cationic surfactants that can disperse the oil phase including the toner components into water include primary, secondary, and tertiary amines having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfoneamidopropyltrimethylammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Specific examples of commercially available products thereof include SURLON S-121 (available from Asahi Glass Co., Ltd.); FRORARD FC-135 (available from Sumitomo 3M Ltd.); UNIDYNE DS-202 (available from Daikin industries, Ltd.); MEGAFACE F-150 and F-824 (available from Dainippon Ink and Chemicals, Inc.); ECTOP EF-132 (available from Tohchem Products Co., Ltd.); FUTARGENT F-300 (available from Neos), and the like.

Further, inorganic compound dispersants which are hardly soluble in water, such as tricalcium phosphate, calcium carbonate, titanium oxide, silica gel, hydroxyapatite and the like, can also be used.

In addition, the toner components may be stably dispersed in water with a polymeric protective colloid. Specific examples of such protective colloids include polymers and copolymers prepared using, for example, the following monomers: acids (e.g., acrylic acid, methacrylic acid, α -cyanoacrylic acid, α -cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, and maleic anhydride), acrylic monomers having a hydroxyl group (e.g., β -hydroxyethyl acrylate, β -hydroxyethyl methacrylate, β -hydroxypropyl acrylate, β -hydroxypropyl methacrylate, γ -hydroxypropyl acrylate, γ -hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, N-methylolacrylamide, and N-methylolmethacrylamide), vinyl alcohols and ethers thereof (e.g., vinyl methyl ether, vinyl ethyl ether, and vinyl propyl ether), esters of vinyl alcohol with compounds having a carboxyl group (i.e., vinyl acetate, vinyl propionate, and vinyl butyrate); acrylamides (such as acrylamide, methacrylamide and diacetoneacrylamide) and methylol compounds thereof, acid chlorides (such as acrylic acid chloride and methacrylic acid chloride), and monomers having a nitrogen atom or alicyclic rings (such as vinylpyridine, vinylpyrrolidone, vinylimidazole and aziridine) having a nitrogen atom. In addition, polymers such as polyoxyalkylene compounds (e.g., polyethylene oxide, polypropylene oxide, polyethylene oxide alkylamine, polypropylene oxide alkylamine, polyethylene oxide alkylamide, polypropylene oxide alkylamide, polyethylene oxide nonylphenyl ether, polyethylene oxide laurylphenyl ether, polyethylene oxide stearylphenyl ester and polyethylene oxide nonylphenyl ester), and cellulose compounds such as methyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose can also be used as the polymer protective colloid.

When an acid such as calcium phosphate or a material dissolved in a base is used as the dispersant, the calcium phosphate is dissolved with an acid such as hydrochloric acid and washed with water to remove the calcium phosphate from the toner particles. In addition to this method, it can also be removed by enzymatic hydrolysis.

When a dispersant is used, the dispersant may remain on the surface of the toner particles. However, in view of charging properties of the resultant toner, the dispersant is preferably washed and removed after the prepolymer is elongated and/or crosslinked with an amine and/or elongated.

Further, in order to reduce the viscosity of the dispersion medium including the toner component, a solvent that can dissolve the prepolymer (a) or the unmodified polyester resin (ii) may be used because the resulting particles have a narrow particle size distribution. The solvent is preferably volatile and has a boiling point below 100c, in view of the ease with which it can be removed from the dispersion after formation of the particles. Specific examples of such solvents include, but are not limited to, toluene, xylene, benzene, carbon tetrachloride, dichloromethane, 1, 2-dichloroethane, 1, 2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and the like. These solvents may be used alone or in combination. Among these solvents, aromatic solvents such as toluene and xylene are preferably used; and halogenated hydrocarbons such as dichloromethane, 1, 2-dichloroethane, chloroform and carbon tetrachloride. These solvents are added in an amount of 0 to 300 parts by weight, preferably 0 to 100, more preferably 25 to 70 parts by weight, based on 100 parts by weight of the prepolymer (A) used. When the solvent is used for preparing a particle dispersion, the solvent is removed therefrom under normal pressure or reduced pressure after subjecting the particles to an elongation reaction and/or a crosslinking reaction of the prepolymer with the amine.

The time of the elongation and/or crosslinking reaction depends on the isocyanate structure of the prepolymer (A) and the activity of the amine (B), but is generally 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally from 0 to 150 ℃ and preferably from 40 to 98 ℃. Furthermore, known catalysts such as dibutyltin laurate and dioctyltin laurate can be used.

To remove the organic solvent from the emulsified dispersion, a method of gradually raising the temperature of the whole dispersion to completely remove the organic solvent in the liquid droplets by evaporation may be used. Further, a method of spraying the emulsified dispersion into air, completely removing the water-insoluble organic solvent from the liquid droplets to thereby form toner particles, and removing the water dispersant by evaporation may also be used. For the dry air, atmospheric air, nitrogen, carbon dioxide gas, gaseous objects in which combustion gas is heated, and particularly various air streams heated to have a temperature not lower than the boiling point of the solvent used are generally used. The spray dryer, the belt dryer and the rotary kiln can sufficiently remove the organic solvent in a short time.

When the emulsified dispersion is washed and dried while maintaining its broad particle size distribution, the dispersion can be classified to have a desired particle size distribution.

Cyclone separators, decanters, centrifuges, and the like can remove particles in the dispersion liquid. The powder remaining after the dispersion liquid is dried may be classified, but in view of efficiency, it is preferable to classify the liquid. The undesirable fine and coarse particles can be recycled into the kneading process to form particles. The fine and coarse particles may be wet when recycled.

The dispersing agent is preferably removed from the dispersion liquid, more preferably at the same time as the above-mentioned classification is performed.

Heterogeneous particles such as release agent particles, charge control agent particles, fluidized particles, and colorant particles can be mixed with the dried toner powder. The heterogeneous particles can be prevented from being released from the composite particles by fixing and fusing them to the surfaces of the composite particles by applying mechanical stress to the mixed powder.

Specific methods include a method of applying an impact force to the mixture with a blade rotating at a high speed, a method of throwing the mixture into a high-speed fluid and accelerating the mixture to cause particles thereof to collide with each other or composite particles thereof to collide with a collision plate, and the like. Specific examples of devices include ONG MILL available from Hosokawa Micron corp, modified I-type MILL with lower pulverizing gas pressure available from Nippon Pneumatic mfg.co., ltd., hybrid System available from Nara Machinery co., ltd, krypton System available from Kawasaki heavy industries, ltd, automatic mortar, and the like.

The toner of the present invention can be used for a two-component developer in which the toner is mixed with a magnetic carrier. The content of the toner is preferably 1 to 10 parts by weight per 100 parts by weight of the carrier. Suitable carriers for the two-component developer include, but are not limited to, known carrier materials such as iron powder, ferrite powder, magnetite powder, and magnetic resin carriers, which have a particle size of about 20 to about 200 μm. The carrier may be coated with a resin. Specific examples of such resins for coating on the carrier include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin and epoxy resin. Further, vinyl or vinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins, styrene-acrylic copolymers, halogenated olefin resins such as polyvinyl chloride resins, polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene resins, vinylidene fluoride-acrylate copolymers, vinylidene fluoride-vinyl fluoride copolymers, copolymers of tetrafluoroethylene, vinylidene fluoride and other monomers not including a fluorine atom, and silicone resins may be used. A conductive powder may be optionally included in the toner. Specific examples of these conductive powders include, but are not limited to, metal powders, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably not more than 1 μm. When the particle diameter is too large, it is difficult to control the resistance of the resulting toner.

The toner of the present invention can also be used as a one-component magnetic or non-magnetic developer without a carrier.

To improve the flow property, preservation property, developability, and transfer property of the resultant developer, an inorganic particulate material such as hydrophobic silica fine powder may be added thereto. Known powder mixers including a jacket, which preferably can control the internal temperature, can be used to mix the external additive and the developer. The external additive may be added gradually to the mixer or during mixing to vary the stress history applied to the external additive. Of course, the number of revolutions of the mixer, the rotational speed, the mixing time and the mixing temperature can be varied. A large stress is initially applied to the external additive and then a relatively small stress is applied thereto, or vice versa. Specific examples of the mixer include a V-type mixer, a rocking mixer, a Loedge mixer, a Nauter mixer, and a Henschel mixer.

Fig. 6 is a schematic diagram illustrating an embodiment of an image forming apparatus of the present invention, in which a copying machine 100 includes a paper feeder 200, a scanner 300 thereon, and A Document Feeder (ADF)400 on the scanner.

The copying machine 100 includes a tandem-type image forming apparatus 20 including four image forming apparatuses 18 in parallel, including means for performing electrophotographic processes such as charging, developing, and cleaning around a photoreceptor 40 as a latent image carrier. Above the tandem-type image forming apparatus 20, an irradiator 21 is provided which irradiates the photoreceptor 40 with a laser beam based on image information, thereby forming a latent image thereon. The intermediate transfer belt 10 formed of an endless belt is disposed facing each photoreceptor 40 in the tandem-type image forming apparatus 20. A transfer device 62 that transfers the toner images of the respective colors formed on the photoreceptors 40 onto the intermediate transfer belt 10 is disposed facing the photoreceptors 40 via the intermediate transfer belt 10.

A second transfer device 22, which simultaneously transfers the toner image overlaid on the intermediate transfer belt 10 onto the transfer sheet from the sheet feeder 200, is provided below the intermediate transfer belt 10. The secondary transfer device 22 includes an endless secondary transfer belt 24 running under tension between two rollers 23, which is pressed to the supporting roller 16 via the intermediate transfer belt 10, thereby transferring the toner image thereon to a transfer sheet. A fixer 25 that fixes the toner image onto the transfer sheet is disposed beside the second transfer device 22. The fixer 25 includes an endless fixing belt 26 and a pressure roller 27 pressed to the fixing belt 26.

The second transfer 22 also transfers the transfer sheet having the transferred image onto the fixing device 25. The second transfer 22 may include a transfer roller and a non-contact charger, in which case the second transfer 22 may have difficulty in conveying the transfer paper.

In the present embodiment, a reverser 28 that reverses transfer paper to record images on both sides thereof is located below the second transferer 22 and the fixer 25, in parallel with the tandem-type image forming apparatus 20.

The developer including the toner of the present invention is used in the image developer 4 in the image forming apparatus 18. The image developer 4 carries and conveys the developer to a position facing the photoreceptor 40 by a developer carrier, thereby developing a latent image thereon under application of an alternating electric field. The alternating electric field activates the developer, limits the charge amount distribution of the toner and improves the developing performance thereof.

The image developer 4 and the photoreceptor 40 may be process cartridges that are separable from the image forming apparatus. The process cartridge may include a charger and a cleaner in addition to the developer and the photoreceptor.

The image forming apparatus operates as follows.

First, an original is first placed on an original table 30 of the ADF400, or on a contact glass 32 of the scanner 300 after the ADF400 is opened, and the ADF is closed to compact the element.

When a start switch (not shown) is pressed, the scanner 300 operates immediately to run a first rotor (runner)33 and a second rotor 34 after the original on the original table 30 is conveyed onto the contact glass 32 and while the original is on it. The first rotor 33 emits light from a light source and reflects reflected light from the original to the second rotor 34. The second rotor 34 reflects the light to a reading sensor 36 with a mirror by an imaging lens 35, thereby reading image information.

When a start switch (not shown) is pressed, a drive motor (not shown) rotates one of the support rollers 14, 15, and 16, and the other two rollers rotate in unison with the rollers driven by the motor, thereby driving the intermediate transfer belt 10. At this time, each image forming device 18 rotates and forms the monochrome images of black, yellow, magenta and cyan formed thereon, and each monochrome image is sequentially transferred onto the intermediate transfer belt 10 to form a composite color image thereon.

When a start switch (not shown) is pressed, a paper feed roller 42 of the paper feeder 200 is selectively rotated, thereby picking up transfer papers from a multi-stage paper feed cassette 44, separating the transfer papers one by a separation roller 45, and transferring the transfer papers to a paper feed path 46. The transfer roller 47 guides the transfer sheet to a sheet feed path 48 in the copying machine 100 while the transfer sheet is stopped against a resist roller 49.

Alternatively, the paper feed roller 50 rotationally picks up the transfer paper on the manual feed tray 51. The separation roller 52 separates the transfer sheets one by one and transfers the transfer sheet to the paper feed path 53, the transfer sheet stopping against the same resist roller 49.

Then, the resist roller 49 is rotated in time when the composite image is formed on the intermediate transfer belt 10, thereby transferring the transfer sheet to the gap between the intermediate transfer belt 10 and the secondary transferer 22 which transfers the composite image onto the transfer sheet.

The transfer sheet having the transferred image is transferred onto the fixing device 25 by the second transfer device 22. After the toner image is fixed to the transfer sheet under pressure and heat, the transfer sheet is switched by the switching pickup 55, and the transfer sheet is conveyed onto the conveying tray 57 by the conveying roller 56. As another mode, the switching pickup 55 switches the transfer sheet to the inverter 28, which inverts the transfer sheet and guides the transfer sheet to the transfer position again so as to transfer the image on the back surface thereof, and the transport rollers 56 transport the transfer sheet onto the transport tray 57.

The intermediate transfer belt 10 removes residual toner remaining thereon after the transfer with an intermediate transfer belt cleaner 17 and is ready for forming another image by the tandem type image forming apparatus 20.

The present invention has been described in general terms, with a further understanding obtained by reference to certain specific examples provided herein for purposes of illustration only and not limitation. In the following description of the examples, numerical values represent weight parts unless otherwise specified.

Examples

Preparation example 1

[ Synthesis of modified polyester resin (A-1) ]

358 parts of an adduct of bisphenol A with 2mol of ethylene oxide, 381 parts of an adduct of bisphenol A with 2mol of propylene oxide, 200 parts of isophthalic acid, 127 parts of terephthalic acid and 2 parts of dibutyltin oxide were mixed and reacted at 230 ℃ for 8 hours under normal pressure in a reactor comprising a cooling tube, a stirrer and a nitrogen inlet tube. The mixture was then decompressed to 10 to 15mm Hg (absolute pressure) and reacted for 5 hours, thereby preparing a polyester prepolymer having a hydroxyl value of 25 and an acid value of 0.9. The polyester prepolymer was cooled to a temperature of 80 ℃. 364 parts of ethyl acetate and 98 parts of isophorone diisocyanate were added thereto, and the mixture was reacted at 110 ℃ for 2 hours, thereby preparing an ethyl acetate solution having a solid content of 75% of a modified polyester resin (A-1), the modified polyester resin (A-1) having a weight average molecular weight (Mw) of 12,000 and 1.29% by weight of NCO.

Preparation example 2

[ Synthesis of blocked amine (B) ]

30 parts of isophorone diamine and 70 parts of methyl ethyl ketone were mixed at 50 ℃ for 5 hours in a reactor equipped with a thermometer and a stirrer, thereby preparing a blocked amine (B).

Preparation example 3

[ Synthesis of Low molecular weight polyester ]

229 parts of an adduct of bisphenol A with 2mol of ethylene oxide, 529 parts of an adduct of bisphenol A with 3mol of propylene oxide, 208 parts of terephthalic acid, 46 parts of adipic acid and 2 parts of dibutyltin oxide were subjected to polycondensation at ordinary pressure and 230 ℃ for 8 hours in a reactor comprising a cooling tube, a stirrer and a nitrogen inlet tube. Then, the mixture was depressurized to 10 to 15mm Hg and reacted for 5 hours, 44 trimellitic anhydride was added thereto and the mixture was reacted at 180 ℃ for 1.8 hours under normal pressure, thereby producing [ low molecular weight polyester 1 ]. The [ low molecular weight polyester 1] had a number average molecular weight of 2,500, a weight average molecular weight of 6,700, a peak molecular weight of 5,000, a Tg of 43 ℃ and an acid value of 25.

Preparation example 4

[ synthetic carbon Black Master batch resin ]

1,200 parts of water, 540 parts of carbon black PRINTEX 35 (available from Degussa A.G, having a DBP oil absorption of 42ml/100mg and a pH of 9.5), 1,200 parts of [ low molecular weight polyester 1] were mixed by means of a kneader under pressure. After kneading the mixture through a two-roll mill having a surface temperature of 150 ℃ for 30 minutes, the mixture was rolled, cooled, and pulverized with a mill, thereby preparing a carbon black master batch resin.

[ Synthesis of mother toner particles (1) ]

100 parts of a carbon black master batch resin, 50 parts of an ethyl acetate solution having a concentration of 10% carnauba wax (which has an average particle diameter of 0.5 μm by wet dispersion with a ball mill), and 70 parts of ethyl acetate were stirred in a beaker until uniformly dispersed, thereby preparing a mixture. Then, 20 parts of the modified polyester resin (a-1) ethyl acetate solution and 1.2 parts of the blocked amine (B) were mixed with the mixture, thereby preparing a liquid having a solid content concentration of 50% comprising the resin and the colorant (1). Next, 560 parts of water, 3.6 parts (solid content only) of an aqueous dispersion of particulate polymethyl methacrylate (PB-200H, available from Kao Corporation) and 3 parts of sodium dodecylnaphthalenesulfonate were added to a liquid including a resin and a colorant (1), and mixed by TK homo mixer (available from TOKUSHU KIKA KOGYO co., LTD.) at 12,000rpm and 25 ℃ for 1 minute, thereby preparing an emulsified dispersion (X).

100 parts of the emulsified dispersion (X) was charged into a stainless steel flask equipped with a helical ribbon type 3-stage stirring blade, and while stirring the emulsified dispersion (X) at 60rpm, ethyl acetate therein was removed under reduced pressure (10kPa) at 25 ℃ for 6 hours to have a concentration of 8%, thereby preparing an emulsified dispersion (Y-1).

10 hours after the preparation of the emulsified dispersion (Y-1), 1.9 parts of carboxymethylcellulose (CELLOGENHH, available from DAI-ICHI KOGYO SEIYAKU CO., LTD.) was added thereto to thicken it. Then, the emulsified dispersion had a viscosity of 6,000 mPas. Then, while stirring the emulsified dispersion at 300rpm, ethyl acetate was removed therefrom under reduced pressure (10kPa) to have a concentration of 3%. Further ethyl acetate was removed therefrom at 60rpm to have a concentration of 1%.

100 parts of the emulsified dispersion was centrifuged to prepare a cake, and 60 parts of water was added thereto to conduct centrifugation again, and this process was repeated 5 times. Then, the final cake was dried at 35 ℃ for 48 hours, thereby preparing mother toner particles (1).

Next, 100 parts of the mother toner particles (1) and 0.4 part of a charge control agent BONTRONX-11 (available from Orient Chemical Industries, Ltd.) were mixed by a Q-type mixer (available from Mitsui miningco., Ltd.) having a turbine blade peripheral speed of 50 m/sec, and the mixing operation included 5 cycles of 2-minute mixing (10 minutes in total) and 1-minute suspension.

Then, 0.5 parts of hydrophobic silica H2000 (available from clariant (japan) K.K.) was mixed at a circumferential speed of 15 m/sec, which mixing operation included 5 cycles of 30 seconds mixing and 1 minute pause, thereby preparing a black toner.

[ preparation example of the Carrier ]

The following materials were mixed and dispersed for 20 minutes by a homogenizer, thereby preparing a coating liquid. The coating liquid was applied to 1,000 parts of spherical magnetite having a particle size of 50 μm by a fluidized bed coater to prepare a magnetic carrier A.

Silicone resin (OrganoLinear siloxane) 100

Toluene 100

Gamma- (2-aminoethyl) aminopropyltrimethoxysilane 5

Carbon Black 10

4 parts of the black toner and 96 parts of the magnetic carrier a were mixed by a ball mill to prepare a two-component developer 1.

Example 1

For the fixer, a fixer available from imagio NEO451 from Ricoh Company, ltd. was used, and MY RECYCLE 100W was set therein to perform a copy test. The cleaning roller was formed of aluminum having a diameter of 10mm and a surface smoothness Rz of 10 μm, a coating liquid in which an active material BONTRON X-11 available from Orient Chemical Industries, Ltd. for increasing the storage modulus (viscoelasticity) of a toner was dissolved in toluene was applied with a brush to the surface of the cleaning roller having a longitudinal length of 300mm and dried to have a dry weight of 0.07g per one cleaning roller.

Example 2

The process of the copy test in example 1 was repeated except that the coating liquid was applied and dried on the cleaning roller to have a dry weight of 0.15g per cleaning roller.

Comparative example 1

The process of example 1 for the copy test was repeated except that the coating liquid was not applied and dried on the cleaning roller.

Thermal offset estimation

Whether the toner was melted out from the cleaning roller to the fixed image was visually observed. The a4 chart having an image area of 6% was continuously copied on both sides of the transfer paper.

O: without heat offset

And (delta): thermal offset was observed

X: the transfer paper is wound and jammed around the cleaning roller

TABLE 1

In example 1, it was judged as "O" until 50,000 images (25,000 images) were produced, and it was judged as "Δ" when 150,000 images were produced, and in example 2, it was judged as "O" until 150,000 images were produced. In comparative example 1, Δ was given when 50,000 images were produced and x was given when 65,000 images were produced, and then the evaluation was stopped.

In comparative example 1, the storage modulus of the toner impurities collected by the cleaning roller was measured when 65,000 images were produced, and in examples 1 and 2, the storage modulus of the toner impurities collected by the cleaning roller was measured when 150,000 images were produced.

Example 3

The procedure of example 1 for the reprographic test was repeated except that [ low molecular weight polyester 1] was added to the coating liquid as a binder resin, the coating liquid was applied to a cleaning roller and dried so that the active material had a dry weight of 0.07g and the binder resin had a dry weight of 0.02g per cleaning roller.

Example 4

The process of example 1 for the reprographic test was repeated except that [ low molecular weight polyester 1] was added to the coating liquid as a binder resin, the coating liquid was applied to a cleaning roller and dried so that the active material had a dry weight of 0.07g and the binder resin had a dry weight of 0.07g per cleaning roller.

Evaluation of exfoliation

Whether the active material was peeled off from the cleaning roller was visually observed. Even when the active material is peeled therefrom, the production of the image is continued until the fixed image is contaminated.

The evaluation results of examples 1,3 and 4 and comparative example 1 are given in table 2.

TABLE 2

Example 5

[ Synthesis of organic particle resin emulsion ]

683 parts of water, 11 parts of a sodium salt of an adduct of sulfuric ester and ethylene oxide methacrylate (ELEMINOL RS-30, available from Sanyo Chemical Industries, Ltd.), 83 parts of styrene, 83 parts of methacrylic ester, 110 parts of butyl acrylate and 1 part of ammonium persulfate were mixed in a reactor including a stirrer and a thermometer, and the mixture was stirred at 400rpm for 15 minutes, thereby preparing a white emulsion therein. The white emulsion was heated to a temperature of 75 ℃ and reacted for 5 hours. Then, 30 parts of an aqueous solution of ammonium persulfate having a concentration of 1% was added thereto and reacted at 75 ℃ for 5 hours, thereby preparing [ particle resin dispersion liquid 1] of a vinyl resin (a copolymer of styrene-methacrylate-butyl acrylate-sulfuric acid ester and a sodium salt of an adduct of ethylene oxide methacrylate). The volume average particle diameter of the [ particle resin dispersion liquid 1] was measured by LA-920 and found to be 0.10. mu.m. The portion [ the particulate resin dispersion liquid 1] is dried to separate the resin component therefrom. The resin component had a Tg of 57 ℃.

[ preparation of aqueous phase ]

990 parts of water, 80 parts of [ particle resin dispersion liquid 1], 40 parts of an aqueous solution of sodium dodecyldiphenylether disulfonate having a concentration of 48.5% (eleminiol MON-7 available from sanyo chemical Industries, Ltd.) and 90 parts of ethyl acetate were mixed and stirred to prepare an emulsion, i.e., [ aqueous phase 1 ].

[ Synthesis of Low molecular weight polyester ]

220 parts of an adduct of bisphenol A with 2mol of ethylene oxide, 561 parts of an adduct of bisphenol A with 3mol of propylene oxide, 218 parts of terephthalic acid, 48 parts of adipic acid and 2 parts of dibutyltin oxide were reacted in a reactor comprising a cooling tube, a stirrer and a nitrogen inlet tube at normal pressure and 230 ℃ for 8 hours. Then, after the mixture was depressurized to 10 to 15mm Hg and reacted for 5 hours, 45 parts of trimellitic anhydride was added thereto and the mixture was reacted at 180 ℃ for 2 hours under normal pressure, thereby producing [ low molecular weight polyester 1 ]. The [ low molecular weight polyester 1] had a number average molecular weight of 2,500, a weight average molecular weight of 6,700, a Tg of 43 ℃ and an acid value of 25mg KOH/g.

[ Synthesis of prepolymer ]

682 parts of an adduct of bisphenol A with 2mol of ethylene oxide, 81 parts of an adduct of bisphenol A with 2mol of propylene oxide, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride, and 2 parts of dibutyltin oxide were reacted at 230 ℃ for 7 hours under normal pressure in a reactor comprising a cooling tube, a stirrer, and a nitrogen inlet tube. Then, the mixture was decompressed to 10 to 15mm Hg and reacted for 5 hours, thereby producing [ intermediate polyester 1 ]. The [ intermediate polyester 1] had a number average molecular weight of 2, 100, a weight average molecular weight of 9,500, a Tg of 55 ℃, an acid value of 0.5 and a hydroxyl value of 49.

Next, 410 parts of [ intermediate polyester 1], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate were reacted at 100 ℃ for 5 hours in a reactor comprising a cooling tube, a stirrer, and a nitrogen inlet tube, thereby preparing [ prepolymer 1 ]. This [ prepolymer 1] included 1.53% by weight of free isocyanate.

[ Synthesis of ketimine ]

170 parts of isophorone diamine and 75 parts of methyl ethyl ketone were reacted at 50 ℃ for 5 hours in a reactor comprising a stirrer and a thermometer, thereby preparing [ ketimine compound 1 ]. The [ ketimine compound 1] has an amine value of 418.

[ Synthesis of Master batch ]

40 parts of carbon black REGAL 400R (available from Cabot Corp.), 60 parts of a binder resin (i.e., polyester resin RS-801 having an acid number of 10, Mw 20,000 and Tg 64 ℃), and 30 parts of water were mixed by a HENSCHEL mixer, thereby preparing water-impregnated pigment agglomerates. It was kneaded for 45 minutes by a two-roll mill having a surface temperature of 130 ℃, spread under pressure, cooled, and pulverized by a pulverizer, thereby preparing [ master batch 1] having a particle size of 1 mm.

[ preparation of oil phase ]

378 parts of [ low molecular weight polyester 1], 100 parts of carnauba wax and 947 parts of ethyl acetate were mixed in a reaction vessel including a stirrer and a thermometer. The mixture was heated to a temperature of 80 ℃ with stirring. After 5 hours at 80 ℃ the mixture was cooled to 30 ℃ over 1 hour. Then, 500 parts of [ master batch 1] and 500 parts of ethyl acetate were added to the mixture, and mixed for 1 hour to thereby prepare [ material solution 1 ].

1,324 parts of [ material solution 1] were transferred to another vessel and carbon black and paraffin were dispersed therein 3 times by a bead mill (Ultra ViscoMill from IMECS co., LTD.) under the following conditions:

the liquid feeding speed is 1kg/hr

The disk peripheral speed is 6 m/sec, and

zirconia balls having a diameter of 0.5mm were filled to 80% by volume.

Next, 1,324 parts of an ethyl acetate solution having a concentration of 65% of [ low molecular weight polyester 1] was added to [ material solution 1], and the mixture was stirred once with a bead mill under the same conditions to prepare [ pigment and wax dispersion liquid 1 ]. The [ pigment and wax dispersion liquid 1] had a solid content concentration of 50%.

[ emulsification ]

648 parts of [ pigment and wax dispersion liquid 1], 154 parts of [ prepolymer 1] and 6.6 parts of [ ketimine compound 1] were mixed in a vessel by a TK-type homogenizer (available from Tokushu Kika Kogyo Co., Ltd.) at 5,000rpm for 1 minute. 1,200 parts of [ aqueous phase 1] was added to the mixture and mixed by a TK-type homogenizer at 13,000rpm for 20 minutes, thereby preparing [ emulsion slurry 1 ].

[ deformation ]

1,000 parts of [ emulsified slurry 1] was mixed by a TK-type homogenizer (available from Tokushu Kika Kogyo Co., Ltd.) at 2,000rpm for 1 hour including 1,365 parts of ion-exchanged water and 35 parts of carboxymethylcellulose CMC DAICEL-1280 (available from DAICEL CHEMICAL INDUSTRIES, LTD.) to prepare [ texturized slurry 1 ].

[ removal of solvent ]

This [ deformation slurry 1] was charged into a vessel including a stirrer and a thermometer, and the solvent was removed therefrom at 30 ℃ for 8 hours, and the slurry was aged at 45 ℃ for 4 hours, thereby preparing [ dispersion slurry 1 ].

[ washingDrying]

After preparing a filter cake by filtering [ dispersion slurry 1] under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake and mixed by a TK-type homogenizer at 12,000rpm for 10 minutes, and the mixture was filtered.

Then, 100 parts of a 10% aqueous solution of sodium hydroxide was added to the filter cake and mixed by a TK-type homogenizer at 12,000rpm for 10 minutes under application of ultrasonic vibration, and the mixture was filtered under reduced pressure. Ultrasonic alkali washing (two ultrasonic alkali washing) is carried out again.

Next, 100 parts of 10% hydrochloric acid was added to the filter cake and mixed by a TK-type homogenizer at 12,000rpm for 10 minutes, and then the mixture was filtered.

300 parts of ion-exchanged water was added to the filter cake and mixed by a TK-type homogenizer at 12,000rpm for 10 minutes, and then the mixture was filtered. This operation was repeated again to prepare filter cake 1. The filter cake 1 was dried at 45 ℃ for 48 hours by an air dryer and sieved through a sieve having 75 μm openings, thereby preparing wood toner particles 1.

Then 100 parts of the mother toner particles 1 and 0.3 part of a charge control agent bontronon E-84 available from origin Chemical Industries, ltd. were mixed by means of a Q-type mixer available from Mitsui Mining co., ltd. where the peripheral speed of the turbine blades thereof was 50 m/sec. The mixing operation included 5 cycles of 2 minutes mixing (10 minutes total) and 1 minute pause.

Further, 0.5 parts of hydrophobic silica H2000 (available from clariant (japan) K.K.) was mixed at a peripheral speed of 15 m/sec, which operation included 5 cycles of 30 seconds of mixing and 1 minute pause, thereby preparing toner 1.

Low temperature fixing property

A 6200 type paper from Ricoh Company, Ltd was placed in imagio NEO450 (from Ricoh Company, Ltd.) of a cleaning roller with a cleaning pressure roller, with the fuser modified to perform the copy test. The fixing roller temperature at which the image density after scraping with the liner is not less than 705 is the lowest fixable temperature. The required temperature is not higher than 170 ℃. The minimum fixable temperature is no more than 170 ℃ and is o. X at a temperature of more than 170 ℃.

Hot offset resistance

The fixing roller temperature at which thermal offset occurs is the thermal offset temperature. The hot offset temperature was O at 220 ℃ or higher. X at a temperature of less than 220 ℃.

Toner fusing

The toner did not melt and contaminate the image even when 100,000 images were produced, and was marked as o; the toner melted and stained the image when 100,000 images were produced and was recorded as x.

Image quality

Defect transfer and image degradation (specifically, background contamination) were comprehensively evaluated. Black solid images were produced to visually observe the extent of defect transfer after 50,000 images were produced by imagio NEO450, available from Ricoh Company, ltd. In the blank image development, imagio NEO450 available from Ricoh Company, ltd. was turned off after 50,000 images were thus produced after development on a tape to allow the developer to be transferred to the photoreceptor. The difference in image density between the tape and the virgin tape was measured by a 938 spectrodensitometer available from X-Rite, inc. Good image quality was good and defective image quality was x.

The toner 1 has a storage modulus G '15, 600 before the active material is added thereto, and a storage modulus G' 29, 100 after the active material is added thereto. The difference was 3,500. The low-temperature fixability, hot offset resistance, image quality, toner fusion of toner 1 were all ≈ o. The fixing roller is not damaged.

This application claims priority to and includes subject matter related to Japanese patent applications 2004-272595, 2004-272161, 2004-226198 and 2004-271385, which were filed at 9/17/2004, 8/2/2004, 9/17/2004, respectively, the entire contents of each of which are incorporated herein by reference.

Having now fully described the invention, it will be apparent to those skilled in the art that many changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth.

Claims (31)

1. A fixer that fixes toner including a binder resin and a colorant onto a recording medium by applying at least one of heat and pressure, comprising:

a fixing member configured to fix toner onto a recording medium;

a pressing member fitted to press the toner thereon;

a cleaning member provided to collect the toner from the fixing member or the pressing member onto the cleaning member, and

a feeder configured to feed an active material to the cleaning member, wherein the active material is a material that reacts with the toner to increase a storage modulus of the toner on the cleaning member, the active material being a metal compound,

wherein the storage modulus of the toner collected on the cleaning member is larger than that before fixing thereof.

2. The fuser of claim 1, further comprising a pressing member configured to press the cleaning member against the fusing member.

3. The fuser of claim 1, further comprising a controller configured to control a nip width between the fusing member and the cleaning member.

4. The fuser of claim 1, wherein the fusing member is a fusing roller and the pressing member is a pressing roller.

5. The fuser of claim 1, wherein the fusing member is a fusing belt extending and suspended over a plurality of rollers, the pressing member is a pressing roller, and the cleaning member is a cleaning roller.

6. The fuser of claim 5, wherein the cleaning roller has a ten-point average roughness Rz3 to 50 μm.

7. The fuser of claim 1, wherein the toner has a storage modulus of 5.0x10 at 120 ℃ prior to heating in the fuser³To 5.0X10⁴Pa, storage modulus at 180 ℃ of 1.0X 10³To 3.0X 10⁴Pa。

8. The fixer according to claim 1, wherein a difference between a storage modulus G '1 of the toner at 120 ℃ before the active material is added thereto and a storage modulus G' 2 at 120 ℃ after the active material is added thereto satisfies the following relationship:

0＜G’2-G’1≤10,000Pa。

9. the fuser of claim 1, wherein the storage modulus at 120 ℃ of the toner collected on the cleaning member is from 1 to 100 times the storage modulus at 120 ℃ prior to heating in the fuser.

10. The fuser of claim 1, wherein the storage modulus at 180 ℃ of the toner collected on the cleaning member is from 1 to 10 times the storage modulus at 180 ℃ prior to heating in the fuser.

11. The fixer according to claim 1, wherein the binder resin includes a polyester resin having an acid value of 1.0 to 50.0 mgKOH/g.

12. The fuser of claim 1, wherein the toner comprises a charge control agent.

13. The fixer according to claim 12, wherein the charge control agent is a salicylic acid metal complex included in the toner in an amount of 0.5 to 6.0% by weight.

14. The fuser of claim 1, wherein the toner further comprises a release agent.

15. The fuser of claim 1, wherein the toner further comprises a metal compound that undergoes an elongation or crosslinking reaction on the prepolymer upon receiving heat.

16. The fuser of claim 15, wherein the metal compound is a salicylic acid metal complex.

17. The fuser of claim 1, wherein the toner has an average circularity of not less than 0.94.

18. The fuser of claim 1, wherein the toner is prepared by:

dissolving or dispersing a polyester resin, a compound having active hydrogen, a polymer having a group capable of reacting with the compound having active hydrogen, a colorant, and a release agent in an organic solvent to prepare a toner component; and

the toner component is dispersed in an aqueous medium to perform at least one of an elongation reaction and a crosslinking reaction on the toner component.

19. The fuser of claim 1, wherein the toner is prepared by:

mixing and kneading a polyester resin, a compound having an active hydrogen, a polymer having a group capable of reacting with the compound having an active hydrogen, a colorant, and a release agent under heating to thereby prepare a kneaded mixture; and

the kneaded mixture was cooled and pulverized.

20. The fixer according to claim 1, wherein the toner has a volume average particle diameter (Dv) of 3.0 to 8.0 μm, and a ratio (Dv/Dn) thereof to a number average particle diameter (Dn) is 1.00 to 1.40.

21. The fuser of claim 1, wherein the toner has a shape factor SF-1 of from 100 to 180 and a shape factor SF-2 of from 100 to 180.

22. The fixer according to claim 1, wherein the toner has a spindle shape in which a major axis particle diameter (r) of the toner₁) With its minor axis particle size (r)₂) Ratio of (r)₂/r₁) 0.5 to 1.0, and the thickness (r) of the toner₃) With its minor axis particle size (r)₂) Ratio of (r)₃/r₂) Is 0.7 to 1.0.

23. The fuser of claim 1, wherein the charger is a charging roller.

24. The fuser of claim 1, wherein the cleaning member comprises a coating layer comprising:

an active material that increases the storage modulus of the binder resin; and

a resin for a coating material, which is capable of forming a coating,

wherein the coating layer is multi-layered.

25. The fixer according to claim 24, wherein a ratio dcore (active material/binder resin) at a contact portion of the coating layer of the cleaning member with the metal shaft and a ratio dsurface (active material/binder resin) of the surface thereof satisfy the following relationship:

d core > D surface.

26. The fuser of claim 24 or 25, wherein the coating layer comprises at least:

a first coating layer overlying the metal shaft of the cleaning member; and

a second coating layer overlying the first coating layer,

wherein the first coating layer includes an active material in an amount per unit weight greater than the second coating layer.

27. The fixer according to claim 26, wherein the first coating layer includes a Reactive Material (RM) and a Coating Resin (CR), and a content (RM/CR) thereof is 30% to 70%/70% to 30% by weight.

28. The fixer according to claim 24, wherein the coating resin has a functional group reactive with the active material at an end thereof.

29. The fuser of claim 28, wherein the functional group is a carboxylic acid.

30. An image forming apparatus comprising:

an image carrier;

a charger configured to charge an image carrier;

an irradiator configured to irradiate an image carrier to form an electrostatic latent image thereon;

an image developer equipped for developing an electrostatic latent image with toner to form a toner image thereon;

a transfer device equipped for transferring a toner image onto a recording member;

a cleaner equipped to remove toner remaining on an image carrier; and

a fixing device equipped for fixing a toner image onto a recording member,

wherein the fixer is a fixer according to any one of claims 1 to 29.

31. A process cartridge detachable from the image forming apparatus of claim 30, comprising an image carrier; and at least one of a charger, an image developer, and a cleaner.