JP2007114751A - Nonmagnetic one-component developer, developing method, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-magnetic one-component developer which is stable in electrostatic charge/resistance for a long period, and can output a high-quality image, an image forming method, and an image forming apparatus. <P>SOLUTION: There are provided the electrostatic charge image developing non-magnetic one-component developer of 30 ml/min in an amount of ventilation by a powder rheometer, 100 mm/sec in the tip speed of a rotor, and 5 to 20 mJ in the amount of total energy at an approach angle -5° of the rotor, the developing method using the non-magnetic one-component developer, and the image forming method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-magnetic one-component developer, a developing method, and an image forming method for developing an electrostatic latent image in an electrophotographic method or an electrostatic recording method.

  A method of visualizing image information through an electrostatic latent image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic latent image formed on a photoreceptor by a charging and exposure process is developed with a developer containing toner, and visualized through a transfer and fixing process. Developers used for development include a two-component developer composed of a toner and a carrier, and a one-component developer used alone, such as a magnetic toner.

  The two-component development method is the most widely used method. However, the developer deteriorates due to the toner particles adhering to the carrier surface, and the developer cannot be maintained for a long time. A toner density control system to keep the density ratio of the toner constant and a mixing device to mix the newly added toner and developer into the developer are required, which increases the size of the developing device. Cheap.

The one-component toner developing method is classified into a magnetic one-component developing method using magnetic toner and a non-magnetic one-component developing method using non-magnetic toner. The magnetic one-component development system uses a developer carrier having a magnetic field generating means such as a magnet inside to hold and develop magnetic toner, and facilitates toner transport control, such as copying machines and printers. In recent years, it has been put into practical use due to its low internal contamination.
However, since the magnetic toner used in the magnetic one-component development system contains a black or brown colored magnetic material such as magnetite, it is difficult to achieve full color. Further, the magnetic one-component developing device has to include a magnet inside the developing roll, and therefore there is a limit to downsizing the developing roll, and further downsizing of the developing device due to this is limited. is there.
On the other hand, the non-magnetic one-component development method does not use a magnetic material for the toner, so it can be colored, and since a magnet is not used for the developer carrier, it is lighter, smaller, and less expensive. Is possible.

By the way, in the two-component development system, a carrier is used as a means for charging and transporting toner, and the toner and the carrier are sufficiently stirred and mixed inside the developing device, and then transported to the developer carrying member and developed. Even in use, it is possible to maintain stable charging and conveyance, and it is easy to cope with a high-speed developing device.
However, in the non-magnetic one-component development method, since there is no stable charging / conveying means like a carrier, charging / conveying defects are likely to occur during long-time use and high speed. As a result, it is difficult to obtain a stable image for a long time as compared with the two-component development method and the magnetic one-component development method, and there are still many improvement issues.

In the above situation, as a method for reducing the occurrence of fog in long-term use and stabilizing the image density, for example, it has been proposed that the ratio of the surface silanol amount and the carbon amount of the external additive be in a specific range ( For example, see Patent Document 1.) Although this method is certainly improved in terms of fog generation and density stability, for example, in an image with a large amount of toner supply such as a solid image, improvement in image density unevenness was insufficient. .
In addition, as a method for reducing the occurrence of fogging during long-term use, it has been proposed that the adhesion ratio of the external additive be in a specific range (see, for example, Patent Document 2). In this method, good developability can be maintained over a long period of time. However, even in this case, the image density unevenness improvement is insufficient for an image having a large amount of toner supply such as a solid image.
JP 2003-195558 A JP 2000-298372 A

  An object of the present invention is to provide a non-magnetic one-component developer, a developing method, and an image forming method capable of outputting a high-quality image with suppressed occurrence of uneven image density over a long period of time.

<1> Non-magnetic for developing electrostatic images with a powder rheometer, with an air flow rate of 30 ml / min, a tip speed of the rotary blade of 100 mm / sec, and a total energy amount of 5 to 20 mJ at the entrance angle of the rotary blade of -5 ° One component developer.

<2> A developer supply member adjacent to the developer carrier supplies the developer onto the developer carrier, and a layer regulating member forms a developer layer having a predetermined charge amount and layer thickness on the developer carrier. And a developing method for developing the latent image on the latent image carrier through the developer layer,
The developer is characterized in that, in a powder rheometer, the air flow rate is 30 ml / min, the tip speed of the rotor blade is 100 mm / sec, and the total energy amount at an approach angle of -5 ° of the rotor blade is 5 to 20 mJ. Development method.

<3> A charging step for charging the electrostatic latent image carrier, a latent image forming step for forming an electrostatic latent image on the surface of the charged electrostatic latent image carrier, and the electrostatic latent image using a developer containing toner. And developing a toner image on the electrostatic latent image carrier, a transfer step of transferring the toner image onto a transfer material to form an unfixed transfer image, and a transfer onto the transfer material. A fixing step of fixing the unfixed transfer image, and an image recording method comprising:
An image forming method using the non-magnetic one-component developer according to <2> in the developing step.

  According to the present invention, it is possible to provide a non-magnetic one-component developer, a developing method, and an image forming method capable of outputting a high-quality image with suppressed occurrence of uneven image density over a long period of time.

  The present inventors have examined the occurrence of image density unevenness, and measured with a powder rheometer at an air flow rate of 30 ml / min, a tip speed of the rotor blade of 100 mm / sec, and an entrance angle of the rotor blade of -5 °. In this case, it has become clear that the use of a developer having a total energy amount of 5 to 20 mJ reduces the occurrence of image density unevenness. This mechanism is not clear, but is presumed as follows.

The occurrence of the image density unevenness is considered to be related to the supply state of the non-magnetic one-component developer to the developer supply member according to the results of the examination so far. In order to support this, it is beneficial to clarify the state of developer adhesion on the surface of the developer supply member. However, the developer supply member is made of urethane sponge or the like so that the developer can be easily adhered. Therefore, it is easy for the developer to enter inside, and it is difficult to make detailed the state of adhesion of the developer. However, if the developer adheres uniformly on the surface of the developer supply member, the image density becomes uniform. Therefore, the developer on the surface of the developer supply member when the image density unevenness occurs is like a lump. It seems to have adhered in a non-uniform state. Further examination makes it possible to estimate that the developer having poor fluidity is adhered to the developer supply member as a lump because the developer tends to aggregate.
Therefore, in the case of a developer that is uniformly supplied to the surface of the developer supply member, it is estimated that the occurrence of uneven image density is reduced.

  As a result of further earnest research, the flow of the developer related to the supply to the developer supply member is 30 m / min in the air flow rate and 100 mm / sec. It has been found that there is a high correlation with the total energy amount of the developer measured at an angle of -5 °. In particular, it has been found that the occurrence of uneven image density can be suppressed when a developer having a total energy amount of 5 to 20 mJ under the measurement conditions is used.

<Development method>
FIG. 1 shows an outline of a general developing device 10 used in the developing method of the present invention.
The developing device 10 stores a non-magnetic one-component developer 12. The developer 12 is stirred by the agitator 17 so that the developer 12 uniformly adheres to the development supply member 14 and does not aggregate. The developer 12 is supplied to the developer carrier 16 by a developer supply member 14 provided inside the developing device 10. The developer 12 on the developer carrier 16 forms a developer layer having a certain thickness by a layer regulating member (blade) 18. The developer carrier 16 is rotatably supported on the outer frame of the developing device 10, and the latent image formed on the electrostatic latent image carrier 20 is developed by the rotation of the electrostatic latent image carrier 20. When reaching the position facing the carrier 16, the latent image comes into contact with the developer layer formed on the developer carrier 16 (or opposed at a certain minute interval), and is developed by the developing bias, and the latent image An image is formed on the carrier 20.

  In this method, the portion corresponding to the electrostatic latent image on the developer carrying member is consumed, but the other portions are not consumed and are collected inside the developing machine. The unconsumed developer is partly peeled off by the developer supply member, and the developer on the remaining developer carrying member passes through the layer regulating blade together with the developer newly supplied by the developer supply member, and is again layered. The

Next, the material of each member of the developing device 10 will be described.
The developer supply member 14 includes, for example, urethane sponge, conductive polypropylene, an acrylic brush, and the like.

  Examples of the developer carrier 16 include a metallic rotating cylinder and an elastic sleeve such as silicone rubber that encloses the metallic rotating cylinder. In addition, the surface of the substrate is subjected to a surface treatment such as oxidation, metal plating, polishing, or blasting in order to control the transportability and chargeability of the metal, such as aluminum, SUS, nickel, or ceramics, and the sleeve. Rigid materials such as plastic sleeves coated with a resin coating such as acrylic and phenol on these substrates and a polymer coat layer in which a charge control agent, a conductive agent, a lubricant, etc. are dispersed, and a plastic sleeve in which these are integrally molded A sleeve can be used.

  As the layer regulating member 18, a rubber elastic blade such as silicone rubber or urethane rubber, or a metal blade such as SUS, Al plate, phosphor bronze or the like can be used. In addition, the blade is coated with a resin such as acrylic, phenol, or urethane, and a resin obtained by mixing these resins with molybdenum disulfide, melamine, graphite, or silicone acrylic, or acrylic, aluminum, or Teflon (registered) (Trademark), vinyl chloride, high-density polyethylene, or a tape, or a plate such as polyoxymethylene, acrylic, or glass may be bonded.

Next, measurement of developer fluidity using a powder rheometer will be described.
When measuring the fluidity of particles, it is more influenced by many factors than when measuring the fluidity of liquids, solids, or gases. It is difficult to specify the exact fluidity of the particles. In addition, even if a factor to be measured (for example, particle size) is determined to specify fluidity, the factor actually has little effect on fluidity or only in combination with other factors. The significance of measuring the factor may arise, and even determining the measurement factor is difficult.
Furthermore, the fluidity of the powder varies significantly depending on external environmental factors. For example, in the case of a liquid, even if the measurement environment changes, the fluctuation range of the fluidity is not so large, but the fluidity of the particles is greatly influenced by external environmental factors such as humidity and the state of the flowing gas. fluctuate. It is not clear which measurement factors are affected by these external environmental factors, so even if measured under strict measurement conditions, the reproducibility of the measured values obtained is actually poor. is there.

  In addition, for the fluidity of toner particles in the developing tank, the angle of repose and the bulk density have been used as indices, but these physical property values are indirect to the fluidity, and the fluidity is quantified. It was difficult to manage.

However, since the powder rheometer can measure the total amount of energy applied from the developer to the rotor blades of the measuring machine, it can be obtained as a sum of the factors attributable to fluidity. Therefore, the powder rheometer determines the items to be measured for the developer obtained by adjusting the surface physical property values and particle size distribution as in the past, and finds and measures the optimum physical property values for each item. Without being able to measure the fluidity directly. As a result, it is possible to determine whether it is suitable as a developer used for developing an electrostatic image only by confirming whether it falls within the above numerical range with a powder rheometer. Such production management of the developer is a method that is extremely suitable for practical use as compared with the conventional method of managing with the indirect value with respect to keeping the fluidity of the developer constant. Moreover, it is easy to make measurement conditions constant, and the reproducibility of measured values is high.
That is, the method for specifying the fluidity by the value obtained by the powder rheometer is simple, accurate and highly reliable as compared with the conventional method.

  In order to prevent image density unevenness from occurring due to non-uniform adhesion to the developer supply member due to poor developer fluidity, when measured with a powder rheometer, the air flow rate is 30 ml / min, rotation It is extremely effective to make the total energy amount of the developer measured at a blade tip speed of 100 mm / sec under the condition of the entrance angle of the rotor blade of -5 ° to be 5 to 20 mJ. Developers within this range have fluidity when used for electrostatic charge image development, the developer uniformly adheres to the developer supply member, and continues to the developer carrier and latent image carrier. The developer is moved in a uniform state. As a result, image defects such as image density unevenness can be prevented.

  When the above measured value with a powder rheometer is lower than 5 mJ, the fluidity is too high, so that the developer is ejected from the vicinity of the developing carrier and the inside of the image forming apparatus may be soiled. On the other hand, when the value exceeds 20 mJ, the occurrence of image density unevenness, which is a problem of the present invention, cannot be suppressed. More preferably, the said measured value is the range of 8-18 mJ, More preferably, it is the range of 10-15 mJ.

Next, a measurement method using a powder rheometer will be described.
The powder rheometer is a fluidity measuring device that directly measures fluidity by simultaneously measuring rotational torque and vertical load obtained by rotating a rotating blade spirally in packed particles. By measuring both the rotational torque and the vertical load, the fluidity including the characteristics of the powder itself and the influence of the external environment can be detected with high sensitivity. In addition, since the measurement is performed with the particle filling state kept constant, data with good reproducibility can be obtained.

In the present invention, measurement is performed using FT4 manufactured by freeman technology as a powder rheometer. In order to eliminate the influence of temperature and humidity before the measurement, a developer that is left at a temperature of 22 ° C. and a humidity of 50% RH for 8 hours or more is used.
First, the developer is filled in a split container with an inner diameter of 50 mm (a cylinder with a height of 51 mm placed on a 160 mL container with a height of 89 mm so that it can be separated vertically) with an amount exceeding 89 mm in height. To do. After the developer is filled, the sample is homogenized by gently stirring the filled developer. This operation will be called conditioning in the following.

In conditioning, the rotating direction that does not receive resistance from the developer so as not to stress the developer in the filled state (depending on the inclination direction of the blade of the rotor blade, but with the rotor blade shown in FIG. Gently agitate the rotor blades (counterclockwise) to remove most of the excess air and partial stress and make the sample homogeneous. Specific conditioning conditions are agitation at a tip angle of 60 mm / sec with an approach angle of 5 °. At this time, the propeller-type rotor blades move downward simultaneously with the rotation, so that the tip draws a spiral, and the angle of the spiral path drawn by the propeller tip at this time is called the entry angle.
After repeating the conditioning operation four times, the container upper end of the split container is gently moved, and the developer inside the vessel is scraped off at a height of 89 mm to obtain a developer filling the 160 mL container. Such an operation is carried out because it is important to always obtain a powder having a constant volume in order to stably obtain the total energy of the present invention.

  The developer thus obtained is transferred to a 200 mL container having an inner diameter of 50 mm, a height of 140 mm, and a mesh bottom plate that can be vented. After the developer was transferred to a 200 mL container, conditioning was further performed 5 times, and then the inside of the container was raised from the bottom to a height of 110 mm to 10 mm at an entrance angle of -5 ° while flowing air at an air flow rate of 30 ml / min. Rotating torque and vertical load when rotating at a tip speed of 100 mm / sec while moving are measured. The direction of rotation of the propeller at this time is the reverse direction to the conditioning (clockwise as viewed from above). Here, the measurement is performed while flowing air at 30 ml / min in order to more closely approximate the flow state of the developer in the developing device. It is considered that aeration at 30 ml / min reproduces a steady flow state in the developing device when the developer is stirred by the agitator. In addition, in FT4 made from freeman technology, the inflow state of ventilation | gas_flowing is specified.

  Measures the rotational torque and vertical load when the rotating blade rotates at a tip speed of 100 mm / sec while moving from the filling surface H1 to H2 through the particles filled in the container at an entrance angle of -5 °. To do.

2A and 2B show the relationship between the rotational torque or the vertical load with respect to the height H from the bottom surface. FIG. 3 shows the energy gradient (mJ / mm) with respect to the height H obtained from the rotational torque and the vertical load. The area (shaded portion in FIG. 3) obtained by integrating the energy gradient in FIG. 3 is the total energy amount (mJ). In the present invention, a total energy amount is obtained by integrating a section from 10 mm to 110 mm in height from the bottom surface.
In the present invention, in order to reduce the influence of errors, the average value obtained by performing this conditioning and energy measurement operation cycle five times is defined as the total energy amount (mJ) defined in the present invention.

  As the rotor blade, a two-blade propeller type φ48 mm diameter blade shown in FIG. 4 manufactured by freeman technology is used.

  The developer used in the present invention is a one-component nonmagnetic developer as described above, and contains at least a binder resin and a colorant. In the case of a one-component developer, the developer is often synonymous with toner particles, and the toner particles contain a binder resin and a colorant as main components. The developer according to the present invention is not particularly limited as long as the above conditions are satisfied.

In order to make the total energy amount of the developer (toner particles) measured within the above conditions within the above range, (1) make the toner particle shape as spherical as possible, (2) contain in the toner particles (3) In the case of containing a wax or the like, it is finely dispersed or contained so as not to bleed out. (4) Toner particle size distribution (5) Toner particles are highly coated with an external additive, and a combination of these methods is also suitable. These conditions are applied to the developer according to the present invention more strictly than the conventional developer. However, the present invention shows that the effects of the present invention can be enjoyed in the image forming method of the present invention by using a developer corresponding to the above total energy amount range. The method and the like are not limited and can be appropriately selected and applied.
The developer (toner particles) according to the present invention can be obtained by referring to the following specific composition and production method.

The composition of the toner particles will be described.
As the binder resin contained in the developer, a known resin that can be used for the toner particles can be appropriately selected. Specifically, for example, monoolefins such as ethylene, propylene, butylene, isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; methyl acrylate, phenyl acrylate, octyl acrylate, Α-methylene aliphatic monocarboxylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether; vinyl methyl ketone, vinyl hexyl ketone And homopolymers or copolymers of vinyl ketone such as vinyl isopropenyl ketone. Among these, particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polystyrene, polypropylene, and the like. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin and the like.

The molecular weight of the binder resin varies depending on the type of resin used, but the approximate weight average molecular weight is preferably 10,000 to 30,000, more preferably 13,000 to 27,000, and 15,000. More preferably, it is ˜25,000.
The value of the said weight average molecular weight says what was measured using the gel permeation chromatography (GPC). GPC uses HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation), and column uses two TSKgel and SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm). THF (tetrahydrofuran) is used. As experimental conditions, the sample concentration is 0.5 mass%, the flow rate is 0.6 ml / min, the sample injection amount is 10 μl, the measurement temperature is 40 ° C., and an IR detector is used.

  The glass transition temperature of the binder resin is preferably 40 ° C. to 70 ° C., and more preferably 45 ° C. to 65 ° C., from the viewpoint of achieving both low-temperature fixability and heat stress resistance in the developing machine.

  The glass transition point (Tg) refers to a value determined by measurement under a temperature rising rate of 3 ° C./minute using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-50). The glass transition point is the temperature at the intersection of the extension line of the base line and the rising line in the endothermic part.

  The colorant is not particularly limited. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment Blue 15: 1, Pigment Blue 15: 3, etc. can be used.

  A charge control agent can be added to the toner particles as necessary. When a charge control agent is added to the color toner, a colorless or light-color charge control agent that does not affect the color tone is preferable. As the charge control agent, known ones can be used, but azo metal complexes, salicylic acid or alkylsalicylic acid metal complexes or metal salts are preferably used.

  Further, the toner particles can contain other known components such as an anti-offset agent such as low molecular weight polypropylene, low molecular weight polyethylene, and wax. As the above wax, paraffin wax and derivatives thereof, montan wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, and the like can be used. Derivatives include oxides, polymers with vinyl monomers, graft modified products, and the like. In addition, alcohols, fatty acids, plant waxes, animal waxes, mineral waxes, ester waxes, acid amides, and the like can be used.

However, as described above, in order to make the numerical range of the toner particles in the powder rheometer within the range specified in the present invention, it is preferable to reduce the offset preventive agent such as wax as much as possible. Although depending on the type of the anti-offset agent used, the content of the wax in the toner particles is preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 8% by mass. More preferably, the content is 1.5% by mass to 6% by mass.
Moreover, when it contains wax etc., it is suitable to make it finely disperse and to make it contain so that it may not ooze out. In the case of a kneaded and pulverized toner, for example, a graft or block copolymer containing at least one of the monomers constituting the polyolefin and the toner binder resin is used as a wax dispersion aid in the case of a kneaded and pulverized toner. It is preferable to mix the toner component. In order to encapsulate wax or the like, it is possible to prepare toner particles by including a wax or the like in the core portion as a core / shell type toner particle by a suspension polymerization method or the like, but not including a wax or the like in the shell portion. preferable.

Furthermore, inorganic fine particles can be internally added to the toner particles in order to facilitate oilless fixing. In order to obtain OHP transparency, inorganic fine particles having a refractive index smaller than that of the toner binder resin are preferable. If the refractive index is too large, the color may become cloudy even in a normal image. SiO ₂ Specific examples of the inorganic fine _{particles, TiO 2, Al 2 O 3} , CuO, ZnO, SnO 2, CeO 2, Fe 2 O 3, MgO, BaO, CaO, K 2 O, Na 2 O, ZrO 2, _{CaO · SiO 2, K 2 O} · (TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, mention may be made of BaSO _4, MgSO _4, and the like.
Of these, silica fine particles and titania fine particles are particularly preferable. The silica fine particles may contain anhydrous silica, aluminum silicate, sodium silicate, potassium silicate, etc., but it is desirable to adjust the composition so that the refractive index is 1.5 or less.

These inorganic fine particles may be previously hydrophobized. Hydrophobic treatment improves the dispersibility of the inorganic fine particles in the toner, and is more effective for the environmental dependency of charging when some of the inorganic fine particles inside the toner are exposed on the toner surface. is there. This hydrophobizing treatment can be performed by immersing inorganic fine particles in a hydrophobizing agent. Although there is no restriction | limiting in particular in a hydrophobization processing agent, For example, a silane coupling agent, a silicone oil, a titanate coupling agent, an aluminum coupling agent etc. can be used. These may be used alone or in combination of two or more. Of these, silane coupling agents are preferred.
The amount of the hydrophobizing agent used varies depending on the type of inorganic fine particles and the like, and cannot be specified unconditionally. However, a range of 5 to 50 parts by weight is usually appropriate for 100 parts by weight of the inorganic fine particles.

In the present invention, it is preferable to add an external additive to the toner particles in order to improve transferability, fluidity, cleaning properties, chargeability controllability, particularly fluidity. The external additive refers to inorganic fine particles attached to the surface of the toner core particles.
_{SiO 2, TiO 2, Al 2} O 3 as the inorganic fine _{particles, CuO, ZnO, SnO 2,} CeO 2, Fe 2 O 3, MgO, BaO, CaO, K 2 O, Na 2 O, ZrO 2, CaO · SiO ₂ , K ₂ O. (TiO ₂ ) _n , Al ₂ O ₃ .2SiO ₂ , CaCO ₃ , MgCO ₃ , BaSO ₄ , MgSO _{4 and the} like can be used. Among these, silica fine particles and titania fine particles are particularly preferable because of good fluidity.

  In the present invention, the average particle size of at least one external additive is 5 to 20 nm, preferably 5 to 16 nm, and more preferably 5 to 12 nm. When the average particle diameter of the external additive is less than 5 nm, the external additive may be embedded in the toner particle surface and may not contribute to the fluidity of the toner particle. On the other hand, when it exceeds 20 nm, the toner particles are easily released from the toner particles, not only contributing to the fluidity of the toner particles, but also free external additives are deposited in the developing device.

  The average particle diameter of the external additive can be directly measured by an electron microscope. In the case of an external additive having an average particle diameter, embedding into the toner particles and desorption from the toner particles are suppressed, so that good fluidity is exhibited and the fluidity is excellent in sustainability.

  As for the usage-amount of the said external additive, the surface coverage calculated by following formula (1) is preferably 50 to 300%, more preferably 80 to 250%, and still more preferably 100 to 200%. In the case of such a surface coverage, it is easy to prepare the toner particles so as to be within the total energy amount range of the powder rheometer according to the present invention.

In the above formula, D _N represents the average particle diameter (μm) of the toner core particles, ρ _N represents the density of the toner core particles, D _a represents the average particle diameter (nm) of the external additive, and ρ _a The density of the external additive is represented, and X represents the addition amount (% by weight) of the external additive.

  It is desirable that the surface of the inorganic fine particles of the external additive has been previously hydrophobized. This hydrophobization treatment improves the powder fluidity of the toner particles and is effective for the environmental dependence of charging. The hydrophobizing treatment can be performed by immersing inorganic fine particles in a hydrophobizing agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together. Of these, silane coupling agents are preferred.

  As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyl Triethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- (trimethylsilyl) ) Urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysila , Γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyl Examples include trimethoxysilane and γ-chloropropyltrimethoxysilane. The amount of the hydrophobizing agent used varies depending on the type of inorganic fine particles and the like, and cannot be specified unconditionally. However, a range of 5 to 50 parts by weight is usually appropriate for 100 parts by weight of the inorganic fine particles.

Further, the degree of hydrophobicity of the external additive by the hydrophobizing agent is preferably 40% to 100%, more preferably 50% to 90%, and still more preferably 60% to 90%.
The degree of hydrophobicity in the present invention is expressed by the following formula when 0.2 g of fine particles are added to 50 cc of water, stirred with a stirrer, titrated with methanol, and the methanol titration when all fine particles are suspended in a solvent is Tcc. Is defined as the degree of hydrophobicity (M).

  Hydrophobicity (M) = [T / (50 + T)] × 100 (vol.%)

  The volume average particle size of the toner particles is preferably 4 μm to 20 μm, more preferably 5 μm to 15 μm, and still more preferably 6 μm to 12 μm. When the volume average particle size of the toner particles is less than 4 μm, the fluidity is remarkably lowered, so that the developer layer is not sufficiently formed by the layer regulating member or the like, and the image may be fogged or dirtied. On the other hand, when it exceeds 20 μm, the resolution is lowered and a high-quality image may not be obtained, or the charge amount per developer unit weight is lowered, and the layer formation maintenance property of the developer layer is lowered, Fog and dirt may occur in the image.

As a method for measuring the volume average particle diameter of the toner particles, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% by weight aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant, and this is added to the electrolytic solution. Added in 100-150 ml. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute. Using the Coulter Counter TA-II type, an aperture having an aperture diameter of 100 μm is used. The particle size distribution of particles in the range of 64 μm is measured. The number of particles to be measured is 50,000.
For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size that becomes 50% cumulative is _defined as the volume average particle size D _50v .

The preferred particle size distribution of the toner particles is when the proportion of toner particles having a particle size of 4 μm or less is 40% by number or less, more preferably 30% by number or less, and even more preferably 20% by number or less. .
Similarly to the determination of the volume average particle diameter D _50v , the particle diameter that is 84% cumulative when the volume cumulative distribution is subtracted from the small particle diameter side is D _84v, and the number cumulative distribution is calculated from the small particle diameter side. When the particle diameter that is 16% is D _16p and the particle diameter that is 50% is D _50p (number average particle diameter), the coarse particle size distribution index = D _84v / D _50v is 1.25 or less. It is preferable that it is 1.20 or less. Further, the fine particle size distribution index = D _50p / D _16p is preferably 1.25 or less, and more preferably 1.20 or less.

In order to obtain toner particles having such a particle size distribution, the particle size distribution can be adjusted to a desired particle size distribution by a gravity classifier, a centrifugal classifier, an inertia classifier, or a sieve sorter. .
In particular, to obtain toner particles having the above particle size distribution, it is preferable to use an air classifier method, and it is particularly preferable to remove fine powder / coarse powder at the same time.

  When the particle size distribution of the toner particles is wider than the above range, the total energy amount by the powder rheometer described above tends to be out of the specified range. On the other hand, if the particle size distribution is to be narrower than the above range, work such as classification becomes excessive and work efficiency becomes extremely poor.

The toner particles are, for example, premixed with a binder resin and a colorant, and optionally a charge control agent, then melt-kneaded in a kneader, cooled and pulverized, and then, as described above, a vibration sieving machine or a wind sieving machine Etc., and can be produced using a kneading and pulverizing method.
Further, it can be produced by a wet spheronization method, a suspension granulation method, a suspension polymerization method, an emulsion polymerization aggregation method or the like.

  The toner particles are preferably made spherical as much as possible in order to obtain the total energy amount according to the present invention. The shape factor SF1 of the toner particles represented by the following formula (2) is preferably 120 or less, and more preferably 115 or less.

Formula (2): SF1 = (ML ² / A) × (π / 4) × 100

In the above formula (2), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.
The toner shape factor SF1 is obtained by taking an optical microscope image of toner particles dispersed on a slide glass into a Luzex image analyzer through a video camera, obtaining a maximum length and a projected area of 50 or more toners, and using the above formula (2). Therefore, it is obtained by calculating and obtaining the average value. SF1 is a true sphere as it approaches 100, and the larger the value, the greater the difference between the maximum length and the minimum length of the particles, which means that the particle becomes indefinite.

The toner particles having the toner shape factor can be obtained by heat treatment after pulverization, or by applying an emulsion polymerization aggregation method or the like.
The heat treatment method is not particularly limited, but it is preferable to perform hot air treatment (for example, SFS-03 manufactured by Nippon Pneumatic Co., Ltd.). Although the temperature and time of the heat treatment depend on the form of the heat treatment apparatus and the glass transition temperature and melting point of the binder resin in the toner, it cannot be generally stated. For example, the SF1 should be 115 or less at 300 ° C. for several minutes. Can do. Note that when the temperature is increased, the time required for setting SF1 to 115 can be shortened. On the other hand, since the toner particles are easily united, it is preferable to appropriately perform the heat treatment.

<Image forming method>
The image forming method of the present invention comprises at least a charging step for charging the electrostatic latent image carrier, a latent image forming step for forming an electrostatic latent image on the surface of the charged electrostatic latent image carrier, and the electrostatic latent image. A development step of developing the image with a developer containing toner to form a toner image on the electrostatic latent image carrier, and a transfer step of transferring the toner image onto a transfer material to form an unfixed transfer image. A fixing step of fixing the unfixed transfer image transferred onto the transfer material. The developer used in the development process is a developer having the above total energy amount.

  In the image forming method of the present invention, known techniques can be appropriately applied to the charging step, the exposure step, the development step, and the transfer step. Further, in addition to these steps, a cleaning step for removing the latent image carrier after the transfer step, a static elimination step, and the like may be performed.

  In the developing step, as in the developing device shown in FIG. 1, the developer adheres to the developer supply member and is transferred from the development supply member to the surface of the developer carrying member. The developer carrying member carrying the developer rotates to face the image carrying member, and the developer is transported to the image carrying member for development.

FIG. 5 shows an example of an image forming apparatus used in the image forming method of the present invention. In FIG. 5, the electrostatic latent image carrier 20, charging means 32 for charging the electrostatic latent image carrier 20, and the charged electrostatic latent image carrier 20 are exposed to expose the surface of the electrostatic latent image carrier 20. Latent image forming means (exposure means) 34 for forming an electrostatic latent image on the surface, developing means 10 for developing the electrostatic latent image with a developer to form a toner image, and carrying the toner image with an electrostatic latent image The image forming apparatus preferably includes a transfer unit 36 that transfers the recording material 20 from the body 20 to a recording material, and a fixing unit 38 that fixes an unfixed transfer image transferred onto the recording material.
Each of these components, that is, the electrostatic latent image carrier (electrophotographic photosensitive member) 20, the charging unit 32, the latent image forming unit 34, the transfer unit 36, the fixing unit 38, the cleaning unit, and the discharging unit (not shown). In the present invention, there is no particular limitation, and any conventionally known structure can be used without any problem. The developing means 10 shown in FIG. 5 is the developing device shown in FIG.
The charging unit 32 in FIG. 5 is a contact type charging unit, but may be a non-contact type charging unit.

The peripheral speed of the developer carrying member is preferably rotated at 150 mm / sec or more and 300 mm / sec or less, and more preferably 170 mm / sec or more and 280 mm / sec or less. When the peripheral speed of the developer carrying member is less than 150 mm / sec, it is not suitable for the recent increase in speed and is not preferable. Moreover, it is inferior in terms of high density reproducibility. On the other hand, when it exceeds 300 mm / sec, especially when applied to a small-sized developing machine, the trimmer distortion occurs due to insufficient mechanical strength of the developing machine, and the density reproducibility is caused by the unevenness of the developer on the developer carrier. Since it may be inferior, it is not preferable.
The developer supply member is preferably in the form of a roll, and the peripheral speed ratio of the developer supply member to the developer carrying member rotates from 0.7 to 1.0 in the direction opposite to the rotation direction of the developer carrying member. It is suitable, and it is more suitable that it is 0.75 or more and 0.95 or less. When the peripheral speed ratio of the developer supplying member is less than 0.7, the ability to peel off the toner on the developing roll is insufficient, and toner deterioration is likely to occur. On the other hand, if it exceeds 1.0, the developer adheres unevenly on the developer supply member and the density reproducibility may be inferior.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

<Measuring method of various characteristics>
First, methods for measuring physical properties of developers and the like used in Examples and Comparative Examples will be described.

-Shape factor-
An optical microscope image of toner particles dispersed on a nuclear slide glass is taken into an image analyzer (LUZEXIII, manufactured by Nireco) through a video camera. From the maximum length and area for 50 particles, from the above formula (2) for each particle SF1 was calculated and the average value was obtained

-Volume average particle size, particle size distribution-
When the particle diameter to be measured is 2 μm or more, a Coulter Counter TA-II type (manufactured by Beckman-Coulter) is used as a measuring device, and an electrolyte is ISOTON-II (manufactured by Beckman-Coulter). Was measured.

  As a measuring method, 10 mg of a measurement sample was added to 2 ml of a 5% by weight aqueous solution of a surfactant and sodium alkylbenzenesulfonate as a dispersant, and this was added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute. Using the Coulter Counter TA-II type, an aperture having an aperture diameter of 100 μm is used. The particle size distribution of particles in the range of 64 μm was measured. The number of particles to be measured was 50,000.

For the divided particle size range (channel), the measured particle size distribution is drawn from the small diameter side for each volume and number, and the volume average particle size is 16% cumulative for all toner particles. The cumulative number particle diameter that is 16% cumulative in diameter D _16v and number is defined as D _16p . Similarly, a particle size that is 50% cumulative in volume is defined as volume average particle size D _50v , and a particle size that is cumulative 50% in number is defined as number average particle size D _50p . Similarly, a particle size that is 84% cumulative in volume is defined as a volume average particle size D _84v , and a cumulative number particle size that is 84% cumulative in number is defined as D _84p . The volume average particle diameter is the D _50v .
For the toner particles, the proportion of particles having a particle size of 4 μm or less was determined from the particle size distribution obtained above.

-Measurement of glass transition temperature-
The glass transition point (Tg) of the binder resin was determined by measurement using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-50) under a temperature increase rate of 3 ° C./min. In addition, the glass transition point was made into the temperature of the intersection of the extended line of the base line in a heat absorption part, and a rising line.

-Measurement of weight average molecular weight-
The weight average molecular weight Mw was measured using gel permeation chromatography (GPC). GPC uses HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation), and column uses two TSKgel and SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm). THF (tetrahydrofuran) was used. As experimental conditions, the sample concentration was 0.5 mass%, the flow rate was 0.6 ml / min, the sample injection amount was 10 μl, the measurement temperature was 40 ° C., and the experiment was performed using an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

<Preparation of base toner>
(Preparation of base toner (1))
Polyester resin 95 parts (terephthalic acid / bisphenol A ethylene oxide adduct / bisphenol A propylene oxide adduct = 50/25/25 (monomer mass ratio) condensation polymer. Tg: 60 ° C., Mw: 20,000)
-Colorant 5 parts (copper phthalocyanine pigment (trade name: ECB301, manufactured by Dainichi Seika Kogyo Co., Ltd.)

The above mixture was mixed with a Henschel mixer and then melt-kneaded with an extruder. After cooling, coarsely pulverized and then finely pulverized with a jet mill, and this fine powder is further refined into fine powder and coarse powder at the cut points of 5.5 μm and 9.2 μm with an elbow jet (product number EJ-LABO, manufactured by Nittetsu Mining Co., Ltd.). The classification operation was repeated three times to obtain a base toner particle group (1) having a volume average particle size of 7.5 μm and a particle size distribution in which the proportion of the particle size of 4 μm or less is 4% by number.
The obtained base toner particle group (1) was subjected to heat treatment at 300 ° C. at a treatment rate of 50 g / hr using a hot air treatment device (SFS-01, produced by Nippon Pneumatic Co., Ltd.) manufactured in Japan Pneumatic Co., Ltd. Toner mother particles (1) were obtained. The average toner shape factor of this toner was 114.

(Preparation of base toners (2) to (5))
In the preparation of the base toner (1), the base toners (2) to (4) were prepared in the same manner except that the classification operation by the elbow jet was repeated three times and the number of times shown in Table 1 was changed. The base toner (5) was prepared in the same manner as the base toner (1) except that no heat treatment was performed in the preparation of the base toner (1). Table 1 shows the volume average particle diameter D _{50v of} the obtained base toners (2) to (5), the ratio of the particle diameter of 4 μm or less, D _84v / D _50v , D _50p / D _16p , and the shape factor SF1. Value.

[Example 1]
(Preparation of external additive toner (1))
To 100 parts by weight of the base toner particles (1), 2.5 parts by weight of silica (particle size: 7 nm, silicone oil (trade name: RY300, manufactured by Nippon Aerosil Co., Ltd.)) is mixed with a Henschel mixer, and external toner (1 )

  The total amount of energy of the externally added toner ((1) thus obtained was measured using a powder rheometer FT4 (manufactured by freeman technology) by the method described above. The total amount of energy of the externally added toner (1) was 12 mJ. Met.

[Examples 2-3]
(Preparation of externally added toners (2) to (3))
The external toner (1) of Example 1 was prepared in the same manner as in Example 2 except that the base toner particles (1) were changed to base toners (2) to (3) as shown in Table 2. Added toners (2) to (3) were prepared. Table 2 shows the total energy amounts of the obtained externally added toners (2) to (3).

[Examples 4 to 5]
External toners (4) to (5) were prepared in the same manner as in Example 1 except that the amount of silica added as an external additive was changed as shown in Table 2. did. Table 2 shows the total energy amount of the obtained externally added toners (4) to (5).

[Comparative Example 1]
A comparative external additive toner (1) was prepared in the same manner as in the preparation of the external additive toner (1) of Example 1, except that 2.5 parts by weight of the external additive was changed to 0.5 parts by weight. Produced. Table 2 shows the total energy amount of the comparative external additive toner (1) obtained.

[Comparative Example 2]
A comparative external additive toner (2) was prepared in the same manner as in the preparation of the external additive toner (2) of Example 2, except that 2.5 parts by weight of the external additive was changed to 3.5 parts by weight. Produced. Table 2 shows the total energy amount of the comparative external additive toner (2) obtained.
[Comparative Examples 3 to 4]
In the preparation of the externally added toner (1) of Example 1, the same procedure was followed except that the base toner particles (1) were changed to the base toners (4) to (5) as shown in Table 2. Externally added toners (3) to (4) were prepared. Table 2 shows the total energy amounts of the comparative external additive toners (3) to (4) obtained.

[Comparative Example 5]
Toner (1) described in Examples of Japanese Patent Application Laid-Open No. 2003-195558 was produced by the method described in the same publication, and comparative external additive toner (5) was obtained. Table 2 shows the total energy amount of the comparative external additive toner (5) obtained.

<Evaluation>
Using the externally added toners of Examples 1 to 7 and Comparative Examples 1 to 4 thus obtained, a speed ratio of the developer supply roll to the rotation speed of the developer carrier using a modified Xerox Phaser 3400B manufactured by Fuji Xerox Co., Ltd. The following copy test was conducted at 0.85 in the reverse direction and a peripheral speed of the developer carrier of 200 mm / sec.
This copy test is a solid image with an area coverage of 100% with an image density of 1.4 to 1.6 measured by a reflection densitometer X-rite 404 manufactured by X-rite in an environment of 28 ° C. and 85% RH. This was done by printing.

(Evaluation of initial image density unevenness)
10 solid images were printed continuously, and for the 10th image obtained, 10 points were equally spaced from the leading edge to the trailing edge in the sheet conveyance direction at the center of the sheet, and the image density was determined by X-rite. A density difference ΔD (maximum density−minimum density) was measured.

(Evaluation of uneven image density after long-term use)
Further, after printing 20,000 sheets, the above solid images were further printed in succession 10 sheets, and the image density unevenness was evaluated by the same evaluation method as the initial image density unevenness.

(Exposure of developer from the developer)
The developer was not ejected from the developing unit, or a sample was prepared for evaluation of uneven image density after long-term use, and then the inside of the apparatus was visually confirmed.

  As shown in Table 2, in the measurement with the powder rheometer under the above conditions, when developing using a non-magnetic one-component developer having a total energy amount of 5 to 20 mJ, the fluidity becomes good, and the image Generation of density unevenness was suppressed over a long period of time, and high-quality images were stably output. When the total energy amount was less than 5 mJ, the image forming apparatus was contaminated by the ejection from the developing device.

It is a schematic block diagram which shows an example of the developing device used for the image development method of this invention. It is a figure for demonstrating the measuring method of the total energy amount with a powder rheometer. It is a figure which shows the relationship between the vertical load and energy gradient which were obtained with the powder rheometer. It is a figure for demonstrating the shape of the rotary blade used with a powder rheometer. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus used in an image forming method of the present invention.

Explanation of symbols

10 Developer (Developing means)
12 Developer 14 Developer Supply Member 16 Developer Carrier 20 Electrostatic Latent Image Carrier 32 Charging Unit 34 Latent Image Forming Unit (Exposure Unit)
36 Transfer means 38 Fixing means

Claims (3)

  Non-magnetic single component development for electrostatic charge image development with a powder rheometer, aeration rate 30ml / min, tip speed of rotor blade 100mm / sec, total energy at rotor blade approach angle -5 ° is 5-20mJ Agent. A developer is supplied onto the developer carrier by a developer supply member adjacent to the developer carrier, and a developer layer having a predetermined charge amount and layer thickness is formed on the developer carrier by a layer regulating member. A developing method for developing a latent image on a latent image carrier via a developer layer,
The developer is characterized in that, in a powder rheometer, the air flow rate is 30 ml / min, the tip speed of the rotor blade is 100 mm / sec, and the total energy amount at an approach angle of -5 ° of the rotor blade is 5 to 20 mJ. Development method. A charging step for charging the electrostatic latent image carrier, a latent image forming step for forming an electrostatic latent image on the surface of the charged electrostatic latent image carrier, and developing the electrostatic latent image with a developer containing toner. A developing process for forming a toner image on the electrostatic latent image carrier, a transfer process for transferring the toner image onto a transfer material to form an unfixed transfer image, and the undetermined image transferred on the transfer material. A fixing step of fixing a transfer image of the wearing, and an image recording method comprising:
An image forming method using the non-magnetic one-component developer according to claim 1 in the developing step.

Images