JP2015127739A - Toner, developer, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner that can meet, in a high-speed full-color image forming method, the further requirement for high image quality and maintain good cleanability for a long period, and a manufacturing method of the toner.SOLUTION: There is provided a toner including a binder resin and a mold release agent, where the average circularity of the toner is 0.96 to 0.99, and 10 to 50 number% of toner particles have, on the surface thereof, one or more recesses having a ratio of the width (A) to the depth (B) (A/B) of 0.3 to 0.9.

Description

  The present invention relates to a toner used for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, and an image forming apparatus and a process cartridge using the toner.

  In recent years, in the technical field of electrophotography, competition for development of color image forming apparatuses capable of high-speed image formation and high image quality is intensifying. Therefore, in order to obtain a full-color image at a high speed, a plurality of electrophotographic photosensitive members are arranged in series in the image forming method, and an image for each color component is formed on each electrophotographic photosensitive member, and is superimposed on the intermediate transfer member. Many so-called tandem systems that perform batch transfer onto a transfer material have been employed (see, for example, Patent Document 1 and Patent Document 2).

  In an image forming apparatus that repeats the process of transferring a transfer toner image formed on the surface of an electrophotographic photosensitive member to a transfer material mainly made of paper, residual toner remaining on the electrophotographic photosensitive member without being transferred to the transfer material after transfer is removed. Therefore, it is essential to remove them sufficiently each time. For this reason, various proposals have been made as cleaning means. However, a cleaning blade made of an elastic material such as urethane rubber is used to scrape the residual toner, which is simple in structure, compact and low cost. In addition, since the toner removing function is excellent, it is widely used. As a rubber material for the cleaning blade, urethane rubber that is high in hardness and rich in elasticity and excellent in wear resistance, mechanical strength, ozone resistance, and the like is generally used.

  However, in a high-speed image forming apparatus represented by on-demand printing, which has been developed in recent years, there is a tendency for wear and chipping at the tip of the cleaning blade to remarkably deteriorate. It is an issue to be established over the years.

  In addition, the high-speed image forming apparatus as described above is required to form a full-color image with higher image quality, and a developer is designed to improve the image quality. In order to meet the demand for higher image quality, particularly full-color image quality, toners are increasingly becoming smaller in particle size and are being studied to faithfully reproduce latent images. To reduce the particle size, a method for producing a toner by a polymerization method that enables the toner to be controlled to have a desired shape and surface structure has been proposed. (For example, refer to Patent Document 3 and Patent Document 4). In the polymerization toner, since the particle size distribution can be reduced in addition to the particle size control and shape control of the toner particles, the toner particles having a small particle size and a relatively uniform particle size improve the reproducibility of dots and fine lines. In addition, the pile height (image layer thickness) can be reduced, and high image quality can be expected.

However, on the other hand, it takes a long time for the polymerization process, and after completion of solidification, it is necessary to separate the solvent and toner particles, and then repeat washing and drying, which requires a lot of time, a lot of water and energy. There is.
In addition, polymerized toners can be expected to improve image quality, but some degree of modification is required for compatibility with cleaning properties and the particle size distribution is not sufficiently narrow. The current situation is that they are not fully answered.

As a method for producing a toner in place of the polymerized toner, a toner composition solution in which a toner composition is dissolved or dispersed in an organic solvent is sprayed and jetted into a gas phase to form droplets, and then the organic solvent is removed to form toner particles. Has been proposed (see Patent Document 5).
In addition, a method has been proposed in which fine droplets are formed using thermal expansion in the nozzle, and the droplets are dried and solidified to become toner (see Patent Document 6).
In addition, a method of performing the same processing using an acoustic lens has been proposed (see Patent Document 7).

However, in these methods, the number of droplets that can be ejected from one nozzle per unit time is small, and there is a problem that productivity is low, and at the same time, the spread of the particle size distribution due to the coalescence of droplets is unavoidable, The toner is not satisfactory in terms of monodispersibility, and the toner obtained by this method has a problem that it is difficult to achieve both cleaning properties because it becomes spherical due to the surface tension of the toner composition liquid.
Thus, no technology has been reported so far that can achieve high levels of cleaning performance and high image quality in the toner and the method of producing the toner.

  Therefore, the present invention has been made in view of the above-mentioned problems, and has a uniform spherical shape with a small particle size that can respond to an unprecedented further demand for higher image quality, and is also easy to clean. An object is to provide a toner having an excellent surface shape.

The feature of the present invention, which is means for solving the above problems, is as described in (1) below.
(1) In a toner containing a binder resin and a release agent, the toner has an average circularity of 0.96 to 0.99, and a width (A) and a depth (B) on the surface of the toner. A toner, wherein a ratio of toner particles having one or more concave portions having a ratio (A / B) of 0.3 to 0.9 is 10 to 50% by number.

  According to the present invention, the above-mentioned problems can be solved and the above-mentioned object can be achieved, and in a high-speed full-color image forming method, further improvement in image quality that has never been achieved by a uniform spherical shape with a small particle diameter can be achieved. It is possible to provide a toner that can satisfy the requirements and can maintain a good cleaning property for a long time due to its surface shape.

It is sectional drawing which shows the structure of a liquid column resonance droplet formation means. It is sectional drawing which shows the structure of a liquid column resonance droplet unit. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 1,2,3. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 4 and 5. It is the schematic which shows the mode of the liquid column resonance phenomenon which arises in the liquid column resonance flow path of a liquid column resonance droplet formation means. It is sectional drawing which shows another structure of a liquid column resonance droplet formation means. 1 is a schematic view of a toner manufacturing apparatus. 3 is an FE-SEM image showing a toner surface shape (needle-like or thread-like concave portion). FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus of the present invention. It is a figure which shows the width | variety (A) and depth (B) of the recessed part in a toner split surface. It is a figure which shows the shape of a recessed part typically.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated based on drawing. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. . The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

Hereinafter, characteristics of the toner used in the image forming apparatus according to the present embodiment will be described.
The toner of the present invention has an average circularity of 0.96 to 0.99, and out of 100 toner particles observed with an electron micrograph, has at least one needle-like or thread-like recess having a maximum length of 1 μm or more. Is preferably contained in an amount of 50 to 100% by number.

  When the average circularity is lower than 0.96, the image uniformity during development deteriorates and the reproducibility of dots and fine lines deteriorates. Further, the electrophotographic photosensitive member to the intermediate transfer member or the intermediate transfer member to the transfer material. The toner transfer efficiency is reduced, and uniform transfer cannot be obtained. In addition, the pile height becomes non-uniform and abnormal images such as uneven glossiness occur, and a high-level high-quality image required for on-demand printing cannot be obtained.

  In the present invention, the toner having one or more recesses having a ratio (A / B) of width (A) to depth (B) of 0.3 to 0.9 out of 100 toner particles observed by TEM. It is necessary that the ratio of particles is 10 to 50% by number. If it is less than 10% by number, the toner is originally a spherical toner having an average circularity of 0.96 to 0.99, so that the toner that passes through the nip while rotating in the nip of the cleaning blade is overwhelmingly increased. Therefore, defective cleaning occurs. If it exceeds 50% by number, the fluidity is lowered and the toner becomes difficult to be charged, so that an abnormal image such as background stains or dust is generated. Further, in order to exhibit the effect of suppressing the rotation of the concave portion in the cleaning blade nip, (A / B) needs to satisfy 0.3 to 0.9, and the toner particles have one or more concave portions outside this range. Even if the ratio is 10 to 50% by number, the same effect cannot be obtained.

It is difficult to obtain a toner particle size distribution in the above range by the conventional pulverization method or polymerization method. A toner having a particle size distribution in the above range can be obtained by a droplet granulation method to be described later. When Dv / Dn) is 1.15 or less, the toner particle size does not become non-uniform, uniform charging is obtained, toner scattering does not occur, and development robustness does not decrease due to selective development, and on demand. It is possible to obtain a high-quality image with a high level as required by printing or the like.
Although it is difficult to obtain a toner having the particle size distribution by a conventional pulverization method or polymerization method, a toner having the particle size distribution can be obtained by using a droplet granulation method described later.

Silica having a primary average particle size of 80 to 500 nm is preferably added to the surface of the toner.
When the primary average particle diameter of silica is smaller than 80 nm, the dam layer is not formed stably, so that the dam layer is easily broken, and the spacer effect cannot be obtained sufficiently, so that the non-electrostatic adhesion force of the toner particles is sufficient. Therefore, it is difficult to reduce the cleaning rate. Furthermore, when mechanical stress with time is large as in a high-speed machine, silica tends to be buried in the toner surface, so that it becomes impossible to suppress poor cleaning over a long period of time. On the other hand, when the primary average particle diameter of silica is larger than 500 nm, the silica itself easily slips through the blade nip, and the toner itself also easily slips from the starting point, resulting in poor cleaning. Further, the fluidity of the toner itself is extremely deteriorated, and the replenishment toner is not sufficiently mixed in the developer, so that it becomes easy to generate scumming.

  The ratio of the silica added is preferably 0.5 to 5 parts by mass, particularly 1 to 4 parts by mass with respect to 100 parts by mass of the toner. When the added ratio is less than 0.5 parts by mass, the spacer effect cannot be sufficiently obtained, so that the non-electrostatic adhesion force of the toner particles cannot be reduced, and cleaning failure tends to occur. On the other hand, when the amount is more than 5 parts by mass, the fluidity of the toner is deteriorated and the uniform transferability is hindered, or the amount of silica released from the toner is increased and the carrier or the photoreceptor is spent and contaminated. There is a fear.

  The carrier particle diameter is preferably 15 to 40 μm in weight average particle diameter. When the thickness is smaller than 15 μm, carrier adhesion is likely to occur in which the carrier is transferred together in the transfer step. On the other hand, if it is larger than 40 μm, carrier adhesion is unlikely to occur, but if the toner concentration is increased in order to obtain a high image density, there is a possibility that scumming is likely to occur. In addition, when the dot diameter of the latent image is small, the variation in dot reproducibility increases, and the graininess of the highlight portion may be deteriorated.

  The contact pressure of the cleaning blade to the electrophotographic photosensitive member is preferably 0.15 to 0.4 N / cm, and particularly preferably 0.18 to 0.3 N / cm. When the contact pressure is less than 0.15 N / cm, the pressure contact with the electrophotographic photosensitive member by the cleaning blade is weak, the toner blocking force is remarkably reduced, and it becomes difficult to form a dam layer, and the toner is easy to slip through. Cleaning performance cannot be realized. When the contact pressure exceeds 0.4 N / cm, a large torque is required to rotate the electrophotographic photosensitive member, and blade squeal is likely to occur. Further, the cleaning blade is bent and deformed, and the electrophotographic photosensitive member is in a so-called belly contact state, resulting in poor cleaning. Furthermore, it also promotes wear of the cleaning blade itself.

  The hardness of the cleaning blade (specified by the JIS-A hardness / JIS K6253 hardness test) is preferably 70 to 80 °, more preferably 72 to 76 °. When the hardness is less than 70 °, the cleaning blade itself is soft and easy to wear, so that toner slip occurs due to the gap caused by the wear, and the cleaning performance tends to deteriorate with time. Further, when the hardness exceeds 80 °, the cleaning blade is likely to be chipped because it is hard, and the cleaning performance tends to deteriorate with time.

  The rebound resilience (specified by the JIS K6255 rebound resilience test) of the cleaning blade is preferably 20 to 60% at 25 ° C., more preferably 30 to 50%. When the rebound resilience is less than 20%, once the toner slips through the blade nip, continuous toner slip occurs at that portion, so that cleaning failure tends to occur. If the rebound resilience exceeds 60%, the stick-slip motion in which the blade edge vibrates minutely becomes intense, causing the blade edge to become fragile, and cleaning failure tends to occur at an early stage.

The cleaning blade is made of a polyurethane material. A polyurethane is obtained by reaction of an isocyanate compound and a polyol compound.
Examples of the isocyanate compound include tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, tolidine diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate. Be

  Examples of the polyol compound include polyether polyol, polyester polyol, acrylic polyol, and epoxy polyol. In addition, as a raw material monomer constituting the acrylic polyol, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, Examples include acrylamide, N-methylol acrylamide, diacetone acrylamide, glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, and acrylonitrile.

  The image forming method of the present invention is preferably a tandem type having a plurality of electrophotographic photoreceptors, charging means, exposure means, developing means, transfer means, and cleaning means. In a so-called tandem type in which a plurality of electrophotographic photosensitive members are arranged and developed one color at a time of each rotation, a latent image forming process and a developing / transfer process are performed for each color to form a toner image of each color. . For this reason, the difference between the single-color image formation speed and the full-color image formation speed is small, and there is an advantage that it can cope with high-speed printing. By the way, the tandem type forms a toner image of each color on a separate electrophotographic photosensitive member, and forms a full color image by laminating (coloring) each color toner layer. For this reason, if there are variations in characteristics, such as different charging properties among the toner particles of each color, there will be a difference in the amount of toner developed by the toner particles of each color, and the change in the hue of the secondary color due to color superposition will increase, in other words If so, the color reproducibility is lowered.

(Toner characteristic evaluation method)
<Average circularity>
As a method for measuring the shape, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera.
The average circularity is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle.
This value is a value measured as an average circularity by a flow type particle image analyzer FPIA-3000.
As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample.
The suspension in which the sample is dispersed is obtained by performing a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10000 / μl.

  In this measurement method, it is important that the concentration of the dispersion is 5000 to 10000 / μl from the viewpoint of measurement reproducibility of average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. The amount of toner added varies depending on the particle size, and it is small for small particle sizes and needs to be increased for large particle sizes. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0.3. By adding 5 g, the dispersion concentration can be adjusted to 5000 to 10000 / μl.

<Recess>
The width (A) and depth (B) of the toner recess are measured from an image obtained by TEM observation.
FIG. 12 is a diagram showing a TEM image showing the width (A) and depth (B) of the recesses in the toner split section.
Here, for TEM observation, for example, after embedding the toner in an epoxy resin, it is sliced with an ultramicrotome (ultrasonic) to produce a toner flake, and this is adjusted with a transmission electron microscope to adjust the magnification of the microscope. By measuring the section of the microscope by expanding the field of view of the microscope until the width (A) and depth (B) of the recess can be measured from the section of the toner Extract as a sample. After the extraction, the width (A) and the depth (B) of the recesses can be obtained from these image files using, for example, image analysis software ImageJ.
As shown in FIG. 12, the width (A) of the concave portion indicates a length obtained by connecting two points on the toner outermost surface side of the concave portion with a straight line in the toner split section by TEM observation. On the other hand, the depth (B) indicates a length obtained by connecting the midpoint of the width (A) and the deepest concave portion with a straight line.
FIG. 13 is a diagram schematically showing various shapes of the recesses.
For example, as shown in FIGS. 13A to 13C, the shape of the recess only needs to satisfy the relationship that the depth (B) is longer than the width (A). As shown in f), the width (A) is not longer than the depth (B).

<Weight average particle diameter (D4), volume average particle diameter (Dv), and number average particle diameter (Dn)>
The weight average particle diameter (D4), volume average particle diameter (Dv), and number average particle diameter (Dn) of the toner are measured using a particle size measuring device (“Multisizer III”, manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm. Measured and analyzed with analysis software (Beckman Coulter Multisizer 3 Version 3.51). Specifically, 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) was added to a glass 100 ml beaker, 0.5 g of each toner was added, and the mixture was stirred with a micropartel. Subsequently, 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter) as the measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the apparatus was 8 ± 2%. In this measurement method, it is important that the concentration is 8 ± 2% from the viewpoint of the reproducibility of the particle size. Within this concentration range, no error occurs in the particle size.

(Carrier characteristics evaluation method)
<Weight average particle size>
The weight average particle diameter Dw of the carrier is calculated based on the particle diameter distribution (relationship between the number frequency and the particle diameter) of the particles measured on the basis of the number. The weight average particle diameter Dw in this case is represented by the formula (1).
Dw = {1 / Σ (nD ³ )} × {Σ (nD ⁴ )} (1)
In formula (1), D represents the representative particle size (μm) of the particles present in each channel, and n represents the total number of particles present in each channel. The channel indicates a length for equally dividing the particle size range in the particle size distribution diagram, and 2 μm is adopted in the present invention. In addition, as the representative particle size of the particles present in each channel, the lower limit value of the particle size of the particles stored in each channel was adopted.

Further, the number average particle diameter Dp of the carrier and the core material particles of the carrier is calculated based on the particle diameter distribution of the particles measured on the basis of the number. The number average particle diameter Dp in this case is represented by the formula (2).
Dp = (1 / ΣN) × (ΣnD) (2)
In formula (2), N represents the total number of particles measured, n represents the total number of particles present in each channel, and D represents the lower limit of the particle size of the particles stored in each channel (2 μm). Show.

In the present invention, a microtrack particle size analyzer model HRA9320-X100 (manufactured by Honeywell) can be used as a particle size analyzer for measuring the particle size distribution. The measurement conditions are as follows.
[1] Particle size range: 8 to 100 μm
[2] Channel length (channel width): 2 μm
[3] Number of channels: 46
[4] Refractive index: 2.42

(Toner production means)
Hereinafter, an example of toner production means used in the image forming method of the present invention will be described with reference to FIGS. The present invention is not limited to the toner production means exemplified here. The toner production means of the present invention is divided into a droplet discharge means and a droplet solidification collecting means. Each is explained below.

[Droplet discharge means]
The droplet discharge means used in the present invention is not particularly limited as long as the particle size distribution of the discharged droplets is narrow, and a known one can be used. Examples of the droplet discharge means include one-fluid nozzle, two-fluid nozzle, membrane vibration type discharge means, Rayleigh split type discharge means, liquid vibration type discharge means, and liquid column resonance type discharge means. The means is described in, for example, Japanese Patent Application Laid-Open No. 2008-292976. A Rayleigh splitting type droplet discharge means is described in, for example, Japanese Patent No. 4647506. A liquid vibration type droplet discharge means is described in, for example, Japanese Patent Application Laid-Open No. 2010-102195.

Any one of the above methods is preferably used to obtain the toner of the present invention.
In order to narrow the particle size distribution of the droplets and ensure the productivity of the toner, for example, liquid droplet resonance can be used. Droplet-like liquid column resonance forms a standing wave by liquid column resonance by applying vibration to the liquid in the liquid column resonance liquid chamber in which a plurality of discharge ports are formed. The liquid is discharged from the formed discharge port.

[Liquid column resonance ejection means]
The liquid column resonance type discharge means that discharges using the resonance of the liquid column will be described.
FIG. 1 shows a liquid column resonance droplet discharge means 11. The liquid common supply path 17 and the liquid column resonance liquid chamber 18 are included. The liquid column resonance liquid chamber 18 communicates with a liquid common supply path 17 provided on one of the wall surfaces at both ends in the longitudinal direction. The liquid column resonance liquid chamber 18 is provided on a wall surface facing the discharge port 19 and a discharge port 19 that discharges the droplet 21 to one wall surface of the wall surfaces connected to both ends. Vibration generating means 20 for generating high-frequency vibrations to form standing waves. The vibration generating means 20 is connected to a high frequency power source (not shown).

As the liquid discharged from the discharge means, a toner component-containing liquid containing a component that forms toner particles is used, but the toner component-containing liquid may be in a liquid state under the conditions for discharging.
As the toner component-containing liquid, a “toner component dissolved / dispersed liquid” in which the component of the toner to be obtained is dissolved or dispersed in a solvent may be used, or the toner component is melted. The “toner component melt” existing in the above may be used.

  The toner composition liquid 14 passes through a liquid supply pipe by a liquid circulation pump (not shown) and flows into the liquid common supply path 17 of the liquid column resonance droplet forming unit 10 shown in FIG. 2, and the liquid column resonance droplet shown in FIG. It is supplied to the liquid column resonance liquid chamber 18 of the discharge means 11. A pressure distribution is formed in the liquid column resonance liquid chamber 18 filled with the toner composition liquid 14 by the liquid column resonance standing wave generated by the vibration generating means 20. Then, the droplet 21 is discharged from the discharge port 19 arranged in a region where the amplitude of the liquid column resonance standing wave has a large amplitude and the pressure fluctuation is large and becomes an antinode of the standing wave.

  The region that becomes the antinode of the standing wave due to the liquid column resonance means a region other than the node of the standing wave. Preferably, it is a region where the pressure fluctuation of the standing wave has an amplitude large enough to discharge the liquid, and more preferably a position where the amplitude of the pressure standing wave becomes a maximum (a section as a velocity standing wave). ) To a minimum position in a range of ± 1/4 wavelength. If the region is an antinode of a standing wave, even if a plurality of discharge ports are opened, it is possible to form substantially uniform droplets from each of them, and more efficiently to discharge droplets. And clogging of the discharge port is less likely to occur.

  The toner composition liquid 14 that has passed through the liquid common supply path 17 flows through a liquid return pipe (not shown) and is returned to the raw material container. When the amount of the toner composition liquid 14 in the liquid column resonance liquid chamber 18 decreases due to the discharge of the liquid droplets 21, a suction force due to the action of the liquid column resonance standing wave in the liquid column resonance liquid chamber 18 acts, and the liquid common supply The flow rate of the toner composition liquid 14 supplied from the passage 17 increases, and the toner composition liquid 14 is replenished in the liquid column resonance liquid chamber 18. When the toner composition liquid 14 is replenished in the liquid column resonance liquid chamber 18, the flow rate of the toner composition liquid 14 passing through the liquid common supply path 17 is restored.

  Each of the liquid column resonance liquid chambers 18 in the liquid column resonance droplet discharge means 11 has a frame formed of a material having such a high rigidity that does not affect the resonance frequency of the liquid at a driving frequency such as metal, ceramics, or silicon. It is formed by bonding. Further, as shown in FIG. 1, the length L between the wall surfaces at both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 is determined based on the liquid column resonance principle as described later. Further, the width W of the liquid column resonance liquid chamber 18 shown in FIG. 2 is desirably smaller than one half of the length L of the liquid column resonance liquid chamber 18 so as not to give an extra frequency to the liquid column resonance. . Furthermore, it is preferable that a plurality of liquid column resonance liquid chambers 18 are arranged for one droplet forming unit 10 in order to dramatically improve productivity. The range is not limited, but one droplet forming unit provided with 100 to 2000 liquid column resonance liquid chambers 18 is most preferable because both operability and productivity can be achieved. In addition, for each liquid column resonance liquid chamber, a flow path for supplying liquid is connected from the common liquid supply path 17, and the common liquid supply path 17 communicates with a plurality of liquid column resonance liquid chambers 18. .

Further, the vibration generating means 20 in the liquid column resonance droplet discharging means 11 is not particularly limited as long as it can be driven at a predetermined frequency, but a form in which a piezoelectric body is bonded to the elastic plate 9 is desirable. The elastic plate constitutes a part of the wall of the liquid column resonance liquid chamber so that the piezoelectric body does not come into contact with the liquid. Examples of the piezoelectric body include piezoelectric ceramics such as lead zirconate titanate (PZT). However, since the amount of displacement is generally small, the piezoelectric body is often used by being laminated. In addition, piezoelectric polymers such as polyvinylidene fluoride (PVDF), single crystals such as quartz, LiNbO ₃ , LiTaO ₃ , KNbO _{3, and the} like can be given. Furthermore, it is desirable that the vibration generating means 20 is arranged so that it can be individually controlled for each liquid column resonance liquid chamber. In addition, a configuration in which the block-shaped vibrating member made of one material described above is partially cut in accordance with the arrangement of the liquid column resonance liquid chambers, and each liquid column resonance liquid chamber can be individually controlled via an elastic plate. desirable.

  Furthermore, the diameter of the opening of the discharge hole 19 is desirably in the range of 1 [μm] to 40 [μm]. By being 1 [μm] or more, it is possible to prevent the droplets from becoming too small and to form droplets of an appropriate size. Even in the case where the toner contains a solid fine particle such as a pigment as a constituent component of the toner, the discharge hole 19 is not clogged, and the productivity can be improved. Moreover, it can prevent that the diameter of a droplet becomes large too much because it is 40 [micrometers] or less. As a result, the toner composition liquid can be dried and solidified without significantly diluting to obtain a desired toner particle diameter of 3 to 6 μm. It may be necessary to dilute the toner composition to a very dilute solution with an organic solvent, which can reduce the amount of organic solvent used for dilution and reduce the drying energy required to obtain a certain amount of toner. Can do.

  Further, as can be seen from FIG. 2, adopting a configuration in which the discharge port 19 is provided in the width direction in the liquid column resonance liquid chamber 18 can provide a large number of openings of the discharge port 19, thereby increasing the production efficiency. Therefore, it is preferable. In addition, since the liquid column resonance frequency varies depending on the opening arrangement of the discharge port 19, it is desirable to appropriately determine the liquid column resonance frequency by confirming the discharge of the droplet.

  Although the cross-sectional shape of the discharge port 19 is described as a tapered shape such that the diameter of the opening is reduced in FIG. 1 and the like, the cross-sectional shape can be appropriately selected.

Next, the mechanism of droplet formation by the droplet formation unit in liquid column resonance will be described.
First, the principle of the liquid column resonance phenomenon that occurs in the liquid column resonance liquid chamber 18 in the liquid column resonance droplet discharge means 11 of FIG. 1 will be described. When the sound velocity of the toner composition liquid in the liquid column resonance liquid chamber is c and the drive frequency given to the toner composition liquid as a medium from the vibration generating means 20 is f, the wavelength λ at which the liquid resonance occurs is
λ = c / f (Formula 1)
Are in a relationship.

In the liquid column resonance liquid chamber 18 of FIG. 1, the length from the end of the frame on the fixed end side to the end on the liquid common supply path 17 side is L. The height h1 (= about 80 [μm]) of the end of the frame on the liquid common supply path 17 side is about twice the height h2 (= about 40 [μm]) of the communication port, and the end is closed. It is equivalent to the fixed end. In the case of such fixed ends on both sides, resonance is formed most efficiently when the length L matches an even multiple of one-fourth of the wavelength λ. That is, it is expressed by the following formula 2.
L = (N / 4) λ (Expression 2)
(However, N is an even number.)

Furthermore, the above formula 2 is also established in the case of a double-sided open end where both ends are completely open.
Similarly, when one side is equivalent to an open end with a pressure relief portion and the other side is closed (fixed end), that is, one side fixed end or one side open end, the length L is the wavelength λ. Resonance is most efficiently formed when it matches an odd multiple of a quarter. That is, N in Expression 2 is expressed as an odd number.

The most efficient drive frequency f is obtained from the above formula 1 and the above formula 2.
f = N × c / (4L) (Formula 3)
It is guided. However, in reality, since the liquid has a viscosity that attenuates the resonance, the vibration is not amplified infinitely, and has a Q value. As shown in equations 4 and 5, which will be described later, Resonance also occurs at frequencies near the highly efficient drive frequency f.

  FIG. 3 shows the shape of the standing wave of the velocity and pressure fluctuation (resonance mode) when N = 1, 2, 3 and FIG. 4 shows the standing wave of the speed and pressure fluctuation when N = 4, 5. The shape (resonance mode) is shown. Although it is originally a sparse / dense wave (longitudinal wave), it is generally expressed as shown in FIGS. The solid line is the velocity standing wave, and the dotted line is the pressure standing wave. For example, as can be seen from FIG. 3A showing the case of a fixed end with N = 1, in the case of velocity distribution, the amplitude of the velocity distribution is zero at the closed end, and the amplitude is maximum at the open end. Easy to understand. When the length between both ends in the longitudinal direction of the liquid column resonance liquid chamber is L, the wavelength at which the liquid resonates is λ, and the standing wave is most efficiently generated when the integer N is 1 to 5. . In addition, since the standing wave pattern varies depending on the open / closed state of both ends, they are also shown. As will be described later, the condition of the end is determined by the state of the opening of the discharge port and the opening of the supply side.

  In acoustics, the open end is an end at which the moving speed of the medium (liquid) in the longitudinal direction becomes zero, and conversely, the pressure becomes maximum. Conversely, the closed end is defined as an end where the moving speed of the medium becomes zero. The closed end is considered as an acoustically hard wall and wave reflection occurs. When ideally completely closed or open, a resonant standing wave of the form shown in FIGS. 3 and 4 is generated by superposition of the waves. However, the standing wave pattern also varies depending on the number of ejection ports and the opening position of the ejection ports, and the resonance frequency appears at a position deviated from the position obtained from the above equation 3. However, the stable ejection conditions can be adjusted by appropriately adjusting the driving frequency. Can be produced.

  For example, the sound velocity c of the liquid is 1,200 [m / s], the length L of the liquid column resonance liquid chamber is 1.85 [mm], wall surfaces exist at both ends, and it is completely equivalent to the fixed ends on both sides. When N = 2 resonance mode is used, the most efficient resonance frequency is derived from the above equation (2) as 324 kHz. In another example, the sound velocity c of the liquid is 1,200 [m / s], the length L of the liquid column resonance liquid chamber is 1.85 [mm], and there are wall surfaces at both ends using the same conditions as described above. Thus, when N = 4 resonance mode equivalent to the fixed ends on both sides is used, the most efficient resonance frequency is derived from the above equation (2) as 648 kHz. Thus, higher-order resonance can be used also in the liquid column resonance liquid chamber having the same configuration.

  The liquid column resonance liquid chamber in the liquid column resonance droplet discharge means 11 shown in FIG. 1 is an end that can be described as a wall that is acoustically soft due to whether the both ends are equivalent to the closed end state or the influence of the opening of the discharge port. Although it is preferable to increase the frequency, it is not limited to this and may be an open end. The influence of the opening of the discharge port here means that the acoustic impedance is reduced, and in particular, the compliance component is increased. Therefore, the configuration in which the wall surfaces are formed at both ends in the longitudinal direction of the liquid column resonance liquid chamber as shown in FIG. 3B and FIG. 4A is regarded as the resonance mode at both fixed ends and the discharge port side as an opening. This is a preferred configuration because all resonance modes at one open end can be used.

  In addition, the numerical aperture of the discharge port, the opening arrangement position, and the cross-sectional shape of the discharge port are factors that determine the drive frequency, and the drive frequency can be appropriately determined according to this. For example, when the number of discharge ports is increased, the restriction at the tip of the liquid column resonance liquid chamber, which has been the fixed end, gradually loosens, a resonant standing wave that is almost close to the open end is generated, and the drive frequency increases. In addition, the opening position of the discharge port that is closest to the liquid supply channel is a starting point, and the loose restriction condition is applied.The cross-sectional shape of the discharge port is round or the volume of the discharge port varies depending on the frame thickness. The upper standing wave has a short wavelength and is higher than the driving frequency.

  When a voltage is applied to the vibration generating means at the drive frequency determined in this way, the vibration generating means is deformed, and a resonant standing wave is generated most efficiently at the drive frequency. Further, the liquid column resonance standing wave is generated even at a frequency in the vicinity of the drive frequency at which the resonance standing wave is generated most efficiently. That is, the length between both ends in the longitudinal direction of the liquid column resonance liquid chamber is L, and the distance to the discharge port closest to the end on the liquid supply side is Le. At this time, the vibration generating means is vibrated using a drive waveform mainly composed of the drive frequency f in the range determined by the following formulas 4 and 5 using the lengths of both L and Le, and liquid column resonance is performed. It is possible to induce and discharge a droplet from the discharge port.

N × c / (4L) ≦ f ≦ N × c / (4Le) (Formula 4)
N × c / (4L) ≦ f ≦ (N + 1) × c / (4Le) (Formula 5)
The ratio of the length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber to the distance Le to the discharge port closest to the end on the liquid supply side is preferably Le / L> 0.6.

  A liquid column resonance pressure standing wave is formed in the liquid column resonance liquid chamber 18 of FIG. 1 using the principle of the liquid column resonance phenomenon described above, and the discharge port 19 disposed in a part of the liquid column resonance liquid chamber 18. In this case, droplet discharge occurs continuously. Note that it is preferable to dispose the discharge port 19 at a position where the standing wave pressure fluctuates the most, because the discharge efficiency becomes high and the device can be driven at a low voltage. Further, although one discharge column 19 may be provided for one liquid column resonance liquid chamber 18, it is preferable to arrange a plurality of discharge ports 19 from the viewpoint of productivity. Specifically, it is preferably between 2 and 100.

  By setting the number to 100 or less, the voltage applied to the vibration generating means 20 can be kept low when a desired droplet is formed from the discharge port 19, and the behavior of the piezoelectric body as the vibration generating means 20 can be stabilized. Can do. Moreover, when opening the some discharge port 19, it is preferable that the pitch between discharge ports is 20 [micrometers] or more and below the length of a liquid column resonance liquid chamber. By setting the pitch between the discharge ports to 20 [μm] or more, it is possible to reduce the probability that droplets discharged from adjacent discharge ports collide with each other to form large droplets, and the toner particle size distribution. Can be good.

  Next, the state of the liquid column resonance phenomenon occurring in the liquid column resonance liquid chamber in the droplet discharge head in the droplet forming unit will be described with reference to FIG. In the figure, the solid line drawn in the liquid column resonance liquid chamber represents the velocity distribution plotting the velocity at any measurement position from the fixed end side to the liquid common supply path side end in the liquid column resonance liquid chamber. The direction from the common liquid supply path to the liquid column resonance liquid chamber is +, and the opposite direction is −. In addition, the dotted line marked in the liquid column resonance liquid chamber indicates a pressure distribution in which the pressure value at each arbitrary measurement position between the fixed end side and the liquid common supply path side end in the liquid column resonance liquid chamber is plotted. The positive pressure is + with respect to the atmospheric pressure, and the negative pressure is-.

  Moreover, if it is a positive pressure, a pressure will be applied to the downward direction in the figure, and if it is a negative pressure, a pressure will be applied to the upward direction in the figure. Further, in the same figure, the liquid common supply path side is opened as described above, but the height of the opening where the liquid common supply path 17 and the liquid column resonance liquid chamber 18 communicate with each other (height h2 shown in FIG. 1). In comparison, the height of the frame serving as the fixed end (height h1 shown in FIG. 1) is about twice or more. For this reason, FIG. 5 shows temporal changes in velocity distribution and pressure distribution under the approximate condition that the liquid column resonance liquid chamber 18 is substantially fixed on both sides.

FIG. 5A shows a pressure waveform and a velocity waveform in the liquid column resonance liquid chamber 18 when a droplet is discharged.
In FIG. 5B, the meniscus pressure increases again after the liquid is drawn immediately after the droplet is discharged. As shown in FIGS. 4A and 4B, the pressure in the flow path in the liquid column resonance liquid chamber 18 provided with the discharge port 19 is maximum. Thereafter, as shown in FIG. 6C, the positive pressure in the vicinity of the discharge port 19 decreases, and the liquid droplet 21 is discharged in a negative pressure direction.

  As shown in FIG. 5D, the pressure in the vicinity of the discharge port 19 is minimized. From this time, the filling of the toner composition liquid 14 into the liquid column resonance liquid chamber 18 starts. Thereafter, as shown in FIG. 5E, the negative pressure in the vicinity of the discharge port 19 becomes smaller and shifts to the positive pressure direction. At this time, the filling of the toner composition liquid 14 is completed. Then, as shown in FIG. 5A again, the positive pressure in the droplet discharge region of the liquid column resonance liquid chamber 18 becomes maximum, and the droplet 21 is discharged from the discharge port 19. As described above, a standing wave due to liquid column resonance is generated in the liquid column resonance liquid chamber by high-frequency driving of the vibration generating means. And since the discharge port 19 is arrange | positioned in the droplet discharge area | region corresponded to the antinode of the standing wave by liquid column resonance which becomes a position where a pressure fluctuates the most, the droplet 21 respond | corresponds according to the period of the antinode. The ink is continuously discharged from the discharge port 19.

-Droplet solidification-
The toner of the present invention can be obtained by solidifying and then collecting the droplets of the toner composition liquid discharged into the gas from the droplet discharge means described above.

-Droplet solidification means-
To solidify, although the way of thinking varies depending on the properties of the toner composition liquid, basically any means can be used as long as the toner composition liquid can be brought into a solid state.
For example, if the toner composition solution is obtained by dissolving or dispersing a solid raw material in a volatile solvent, it can be achieved by drying the droplets in the conveying airflow after jetting the droplets, that is, volatilizing the solvent. In drying the solvent, the drying state can be adjusted by appropriately selecting the temperature, vapor pressure, gas type, and the like of the gas to be injected. Further, even if the particles are not completely dried, they may be additionally dried in a separate step after the collection as long as the collected particles maintain a solid state. Even if it does not follow the said example, you may achieve by application of a temperature change, a chemical reaction, etc.

-Means for collecting solidified particles-
The solidified particles can be recovered from the air by a known powder collecting means such as a cyclone collecting or a back filter.
FIG. 6 is a cross-sectional view of an example of an apparatus for carrying out the toner manufacturing method of the present invention. The toner manufacturing apparatus 1 mainly includes a droplet discharge means 2 and a dry collection unit 60.

The droplet discharge means 2 is connected to a raw material container 13 that stores the toner composition liquid 14 and a liquid circulation pump 15 that pumps the toner composition liquid 14. The liquid circulation pump 15 supplies the toner composition liquid 14 stored in the raw material container 13 to the droplet discharge means 2 through the liquid supply pipe 16 and further returns to the raw material container 13 through the liquid return pipe 22. The toner composition liquid 14 in the supply pipe 16 is pumped. With such a configuration, the toner composition liquid 14 is supplied to the droplet discharge means 2 as needed. The liquid supply pipe 16 is provided with a pressure measuring device P1 and the dry collection unit is provided with a pressure measuring device P2. Managed by. At this time, if the relationship of P1> P2 is satisfied, the toner composition liquid 1 may ooze out from the hole 12, and if P1 <P2, there is a possibility that gas enters the discharge means and the discharge stops. It is desirable that P1≈P2.
In the chamber 61, a descending airflow 101 created from the carrier airflow inlet 64 is formed. The droplets 21 discharged from the droplet discharge means 2 are transported downward not only by gravity but also by the transport airflow 101 and are collected by the solidified particle collecting means 62.

-Conveyance airflow-
When the ejected droplets come into contact with each other before drying, the droplets coalesce and become one particle (hereinafter, this phenomenon is called coalescence). In order to obtain solidified particles having a uniform particle size distribution, it is necessary to maintain the distance between the ejected droplets. However, the ejected droplets have a constant initial velocity, but eventually become stalled due to air resistance. The jetted droplets catch up with the stalled particles and coalesce as a result. Since this phenomenon occurs constantly, the particle size distribution is greatly deteriorated when the particles are collected. In order to prevent coalescence, it is necessary to transport the liquid droplets while solidifying the droplets while preventing the liquid droplets from decreasing in speed and preventing the coalescence by the conveying airflow 101 so that the droplets do not contact each other. Carry the solidified particles to the collection means.

For example, as shown in FIG. 1, a part of the transport airflow 101 is arranged as a first airflow in the vicinity of the droplet discharge means in the same direction as the droplet discharge direction, thereby reducing the droplet velocity immediately after the droplet discharge. Can be prevented and coalescence can be prevented. Alternatively, as shown in FIG. 7, the direction may be transverse to the ejection direction. Alternatively, although not shown, it may have an angle, and it is desirable to have an angle at which the droplets are separated from the droplet discharge means. As shown in FIG. 7, when the anti-adhesion airflow is applied from the lateral direction with respect to the droplet discharge, the trajectory may not be overlapped when the droplets are conveyed by the anti-adhesion airflow from the discharge port. desirable.
After preventing coalescence by the first air stream as described above, the solidified particles may be carried to the solidified particle collecting means by the second air stream.

It is desirable that the velocity of the first air flow is equal to or higher than the droplet jet velocity. If the speed of the anti-adhesion airflow is lower than the droplet ejection speed, it is difficult to exert the function of preventing the droplet particles, which is the original purpose of the anti-adhesion airflow, from contacting.
The property of the first air stream can be added with a condition such that the droplets do not coalesce with each other, and may not necessarily be the same as the second air stream. Further, a chemical substance that promotes solidification of the particle surface may be mixed in the anti-adhesion airflow, or may be imparted in anticipation of physical action.

  The carrier airflow 101 is not particularly limited as a state of the airflow, and may be a laminar flow, a swirl flow, or a turbulent flow. There is no particular limitation on the type of gas constituting the carrier airflow 101, and air or a nonflammable gas such as nitrogen may be used. Moreover, the temperature of the conveyance airflow 101 can be adjusted as appropriate, and it is desirable that there is no fluctuation during production. Further, a means for changing the airflow state of the carrier airflow 101 in the chamber 61 may be taken. The carrier airflow 101 may be used not only to prevent the droplets 21 from being attached to each other but also to prevent the droplets 21 from adhering to the chamber 61.

[Secondary drying]
When the amount of residual solvent contained in the toner particles obtained by the dry collection means shown in FIG. 6 is large, secondary drying is performed as necessary to reduce this. As the secondary drying, general known drying means such as fluidized bed drying or vacuum drying can be used. If the organic solvent remains in the toner, not only the toner characteristics such as heat-resistant storage stability, fixing properties, and charging characteristics will change over time. Since the organic solvent volatilizes during fixing by heating, the possibility of adverse effects on the user and peripheral equipment is increased. Therefore, sufficient drying is performed.

The toner of the present invention contains at least a binder resin, a colorant, and a release agent, and if necessary, contains a fixing aid, a charge adjusting agent, an additive, and other components.
The “toner composition liquid” used in the present invention will be described. The toner composition liquid is in a liquid state in which the above toner components are dissolved or dispersed in a solvent, or may be free from a solvent as long as it is liquid under the conditions of ejection, and a part or all of the toner components are melted. In a liquid state.
As the toner material, if the above toner composition liquid can be adjusted, the same material as that of a conventional electrophotographic toner can be used. As described above, the droplets are made into fine droplets by the droplet discharge means, and the target toner particles can be produced by the droplet solidification collecting means.

(Organic solvent)
The organic solvent is not particularly limited as long as it can dissolve the binder resin and stably disperse the dispersion such as the colorant, and can be appropriately selected according to the purpose. When collecting the toner with a cyclone, it is necessary to dry and collect the toner composition liquid in the gas phase to some extent. Therefore, a solvent that can be easily dried is preferable. From the viewpoint of drying, the boiling point of the solvent is preferably 100 ° C. or less.

  As the organic solvent, for example, ethers, ketones, esters, hydrocarbons, and alcohols are preferable, and tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), ethyl acetate, and toluene are more preferable. These may be used individually by 1 type and may use 2 or more types together.

(Binder resin)
There is no restriction | limiting in particular as binder resin, According to the objective, it can select suitably. For example, vinyl polymers such as styrene monomers, acrylic monomers, methacrylic monomers, copolymers of these monomers or two or more types, polyester polymers, polyol resins, phenol resins , Silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, terpene resin, coumarone indene resin, polycarbonate resin, petroleum resin, and the like.
As the properties of the binder resin, it is desirable that the binder resin be dissolved in a solvent.

―Molecular weight distribution of binder resin―
The molecular weight distribution of the binder resin by GPC (gel permeation chromatography) and at least one peak in the region of molecular weight of 3,000 to 50,000 are preferable from the viewpoint of toner fixing property and offset resistance. In addition, as a THF soluble component, a binder resin in which a component having a molecular weight of 100,000 or less is 60 to 100 [%] is preferable, and a binder having at least one peak in a region having a molecular weight of 5,000 to 20,000. A resin is more preferable.
Of these, polyester polymers are particularly desirable from the viewpoint of low-temperature fixability.

-Measurement method of exothermic peak temperature, melting point, and glass transition temperature (Tg)-
The heat generation peak temperature, melting point, and glass transition temperature (Tg) of the toner and each material in the present invention are measured using, for example, a DSC system (differential scanning calorimeter) (“DSC-60”, manufactured by Shimadzu Corporation). be able to.

Specifically, the exothermic peak temperature, melting point, and glass transition temperature of the target sample can be measured by the following procedure.
First, about 5.0 mg of a target sample is placed in an aluminum sample container, and the sample container is placed on a holder unit and set in an electric furnace. Next, the sample is heated from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere. Thereafter, the temperature is cooled to 0 ° C. at a temperature drop rate of 10 ° C./min from 200 ° C., and further heated to 200 ° C. at a temperature rise rate of 10 ° C./min. ) To measure the DSC curve.

  From the obtained DSC curve, using the analysis program “endothermic shoulder temperature” in the DSC-60 system, the DSC curve at the first temperature rise is selected, and the glass transition temperature at the first temperature rise of the target sample is obtained. Can do. Further, by using the “endothermic shoulder temperature”, a DSC curve at the second temperature rise can be selected, and the glass transition temperature at the second temperature rise of the target sample can be obtained.

Further, from the obtained DSC curve, the DSC curve at the first temperature rise is selected using the analysis program “peak temperature analysis program” in the DSC-60 system, and the melting point at the first temperature rise of the target sample is obtained. be able to. Further, by using the “endothermic peak temperature”, a DSC curve at the second temperature rise can be selected, and the melting point at the second temperature rise of the target sample can be obtained.
Similarly, using the “peak temperature analysis program”, a DSC curve at the first temperature drop can be selected, and the exothermic peak temperature at the first temperature drop of the target sample can be obtained.

In the present invention, the glass transition temperature at the first temperature rise when the toner is used as the target sample is Tg1st, and the glass transition temperature at the second temperature rise is Tg2nd.
Moreover, in this invention, melting | fusing point and Tg at the time of the 2nd temperature rise of each structural component are made into melting | fusing point and Tg of each object sample.

(Fixing aid)
The fixing auxiliary component in the present invention is present in the toner as an independent crystalline domain from the binder resin before being heated by the fixing unit, and is quickly melted by heating at the time of fixing, so that the binder resin It has the effect of promoting softening. Since the binder resin is not softened before fixing, it has excellent heat-resistant storage stability and has an action of softening the binder resin at the time of fixing, so that excellent low-temperature fixability can be exhibited.

Further, the fixing aid component can also exhibit a toner deforming effect. Although the reason for this is not clear, it is considered that the surface shape of the toner follows the crystal domain shape of the fixing aid due to the presence of the crystal domain of the fixing aid in the toner. Even if it is said to be deformed, since the toner surface shape changes in a form that follows the crystal domain of the fixing aid, a drastic change in the average circularity is not seen, but the recess defined in the present invention appears. The surface shape of the toner changes due to. That is, the surface shape changes while maintaining the spherical shape in appearance, thereby making it possible to achieve both high image quality and cleanability. It has been found that changing the number of toner particles having recesses according to the amount of the fixing aid is effective as one means. The amount of the fixing aid added varies depending on the type of the fixing aid, but is preferably about 5% to 30%. If it is less than 5%, a recess having a ratio (A / B) of the recess width (A) to depth (B) greater than 0.9 is likely to appear, and one or more recesses defined in the present invention are present. The ratio of the toner particles to be contained is less than 10% by number. On the other hand, if it is more than 30%, the ratio of toner particles having one or more recesses as defined in the present invention will be more than 50% or the ratio of width (A) to depth (B). Many recesses with (A / B) smaller than 0.3 will appear.
A linear alkyl fatty acid having an ester group is very effective for the modification of the toner.

Examples of the fixing aid include fatty acid esters, esters of aromatic acids such as phthalic acid, phosphoric esters, maleic esters, fumaric esters, itaconic esters, and other esters.
Preferred long-chain alkyl groups in fatty acids are more preferably C12 to C25 such as stearyl, behenyl and the like. This is because if the carbon number is smaller than C12, the effect of changing the toner is reduced, and if it is larger than C26, the low-temperature fixing property is adversely affected. Preferable specific examples include diethylene glycol stearate.
A compound having the above structure and having a melting point of 120 ° C. or lower is used as a fixing auxiliary component of the present invention. 100 ° C. or lower, more preferably 90 ° C. or lower. This is because if the melting point is higher than 120 ° C., sufficient low-temperature fixability cannot be obtained.

(Release agent)
The toner composition liquid used in the present invention contains a release agent together with a binder resin and a colorant.
There is no restriction | limiting in particular as a mold release agent, Usually used thing can be selected suitably, and can be used. For example, aliphatic hydrocarbon release agents such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin release agents, microcrystalline release agents, paraffin release agents, sazole release agents, and aliphatics such as oxidized polyethylene release agents Oxides of hydrocarbon release agents or their block copolymers, candelilla release agents, carnauba release agents, plant release agents such as wood wax, jojoba wax, and animal systems such as beeswax, lanolin, spermaceti Release agents, mineral release agents such as ozokerite, ceresin, and petrolatum, release agents based on fatty acid esters such as montanate ester release agents and caster release agents, deacidified carnauba release agents, etc. And those obtained by deoxidizing a part or all of the fatty acid esters.

The melting point of the release agent is preferably 70 to 140 [° C.] and more preferably 70 to 120 [° C.] in order to balance the fixing property and the offset resistance. If it is less than 70 [° C.], the blocking resistance may be lowered, and if it exceeds 140 [° C.], the offset resistance effect may be difficult to be exhibited.
The total content of the release agent is preferably 0.2 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

In the present invention, the temperature of the peak top of the endothermic peak of the release agent measured by DSC (differential scanning calorimetry) is defined as the melting point of the release agent.
As the DSC measuring device for the release agent or toner, it is preferable to perform measurement with a highly accurate internal heat input compensation type differential scanning calorimeter. As a measuring method, it carries out according to ASTM D3418-82. The DSC curve used in the present invention is one that is measured when the temperature is raised at a temperature rate of 10 [° C./min] after raising and lowering the temperature once and taking a previous history.

(Coloring agent)
The colorant is not particularly limited, and a commonly used colorant can be appropriately selected and used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow ( GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Iso Indolinone Yellow, Bengala, Pangdan, Lead Red, Cadmium Red, Cadmium Mercury Red, Antimony Zhu, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilli Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon , Oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine oren , Perinone orange, oil orange, cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, Ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Titanium Oxide, Zinc white, litbon and mixtures thereof can be used.
The content of the colorant is preferably 1 to 15% by mass and more preferably 3 to 10% by mass with respect to the toner.

  The colorant used in the present invention can also be used as a master batch combined with a resin. The binder resin kneaded with the master batch includes polyester resin, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and substituted polymers thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer Polymer, 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-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, Styrene-vinyl Styrene copolymers such as tilketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin Aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, and the like. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

The master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. Also, there is a method of removing the water and organic solvent components by mixing and kneading an aqueous paste containing water, which is a so-called flushing method, together with a resin and an organic solvent, and transferring the colorant to the resin side. Since the wet cake can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shearing dispersion device such as a three-roll mill is preferably used.
As the usage-amount of the said masterbatch, 2-30 mass parts is preferable with respect to 100 mass parts of binder resin.

  The resin for the masterbatch preferably has an acid value of 30 mgKOH / g or less, an amine value of 1 to 100 mgKOH / g, and a colorant dispersed therein. The acid value is 20 mgKOH / g or less, the amine value Is more preferably 10 to 50 mg KOH / g, and the colorant is dispersed and used. When the acid value exceeds 30 mgKOH / g, the chargeability under high humidity may be lowered, and the pigment dispersibility may be insufficient. Further, when the amine value is less than 1 mgKOH / g and when the amine value exceeds 100 mgKOH / g, the pigment dispersibility may be insufficient. The acid value can be measured by the method described in JIS K0070, and the amine value can be measured by the method described in JIS K7237.

  The dispersant is preferably highly compatible with the binder resin in terms of pigment dispersibility. Specific examples of commercially available products include “Ajisper PB821” and “Azisper PB822” (manufactured by Ajinomoto Fine Techno Co., Ltd.). , “Disperbyk-2001” (manufactured by Big Chemie), “EFKA-4010” (manufactured by EFKA), and the like.

(Charge control agent)
The toner of the present invention is not particularly limited as a charge control agent. However, from the viewpoint of solubility in an organic solvent, the toner of the present invention has a negative chargeability containing a polycondensate obtained by polycondensation reaction of phenols and aldehydes. A charge control agent was used.
The phenols are composed of p-alkylphenol, p-aralkylphenol, p-phenylphenol, and p-hydroxybenzoic acid ester having one phenolic hydroxyl group and hydrogen bonded to the ortho position of the hydroxyl group. Mention may be made of at least one phenolic compound selected from the group. Examples of the aldehydes include aldehydes such as paraformaldehyde, formaldehyde, paraaldehyde, and furfural.
Examples of the charge control agent that is commercially available include a charge control agent (Fujikura Kasei Co., Ltd.) containing an FCA-N type condensation polymer.

  As an additive of the toner according to the present invention, it is intended to protect the electrostatic latent image carrier / carrier, improve the cleaning property, adjust the thermal property / electric property / physical property, adjust the resistance, adjust the softening point, improve the fixing rate, etc. As various metal soaps, fluorine surfactants, dioctyl phthalate, tin oxide, zinc oxide, carbon black, antimony oxide, etc. as conductivity imparting agents, inorganic fine powders such as titanium oxide, aluminum oxide, alumina, etc. It can be added as necessary. These inorganic fine powders may be hydrophobized as necessary. In addition, lubricants such as polytetrafluoroethylene, zinc stearate, polyvinylidene fluoride, abrasives such as cesium oxide, silicon carbide, strontium titanate, anti-caking agents, white particles and black particles having opposite polarity to the toner particles, Can also be used in small amounts as a developability improver.

  These additives have a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, and other organosilicons for the purpose of charge control and the like. It is also preferable to treat with a treating agent such as a compound or various treating agents.

As the additive, inorganic fine particles can be preferably used. As said inorganic fine particle, well-known things, such as a silica, an alumina, a titanium oxide, can be used, for example.
In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.

  Such an external additive can be made hydrophobic by the surface treatment agent and prevent deterioration of the external additive itself even under high humidity. Examples of the surface treatment agent include a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, a modified silicone oil, Etc. are preferable.

  The primary particle diameter of the external additive is preferably 5 [nm] to 2 [μm], and more preferably 5 [nm] to 500 [nm]. Moreover, as a specific surface area by BET method, it is preferable that it is 20-500 [m2 / g]. The use ratio of the inorganic fine particles is preferably 0.01 to 5 [% by mass] of the toner, and more preferably 0.01 to 2.0 [% by mass].

  Examples of the cleaning property improver for removing the developer after transfer remaining on the electrostatic latent image carrier or the primary transfer medium include fatty acid metal salts such as zinc stearate, calcium stearate, stearic acid, and polymethyl methacrylate. There may be mentioned polymer fine particles produced by soap-free emulsion polymerization such as fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 [μm].

When the toner is used as a two-component developer, it may be used by mixing with a magnetic carrier, and the carrier to toner content ratio in the developer is preferably a toner concentration of 1 to 10 wt% as the developer.
As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 50 μm can be used.

  Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride And fluoro such as terpolymers of non-fluoride monomers including, and silicone resins.

Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
The toner can also be used as a one-component magnetic toner or a non-magnetic toner that does not use a carrier.

According to the present invention, there are provided a tandem type image forming apparatus and an image forming method having at least a plurality of electrophotographic photoreceptors, charging means, exposure means, and transfer means. As a result, a good full-color image can be obtained at a very high speed as compared with the one-drum type image forming apparatus.
Further, according to the present invention, the intermediate transfer means for primarily transferring the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member and then secondary transferring the toner image on the intermediate transfer member onto the recording material. An image forming apparatus having a plurality of color toner images sequentially superimposed on an intermediate transfer member to form a color image, and the color image is secondarily transferred onto a recording material in a batch to thereby prevent color misregistration. A suppressed and good image is provided. Further, the layout through the intermediate transfer member improves the degree of freedom of layout in the image forming apparatus, and achieves downsizing of the apparatus and improvement in maintainability.

(Process cartridge)
The developer of the present invention can be used in, for example, an image forming apparatus provided with a process cartridge as shown in FIG.
In the present invention, a plurality of components such as a photosensitive member, a charging unit, a developing unit, and a cleaning unit are integrally combined as a process cartridge, and the process cartridge is formed in an image forming apparatus such as a copying machine or a printer. It is configured to be detachable from the apparatus main body.

The process cartridge 71 shown in FIG. 9 includes a photoreceptor 72, a charging unit 73, a developing unit 74, and a cleaning unit 75. The operation of the process cartridge will be described below.
First, the photoconductor 72 is driven to rotate at a predetermined peripheral speed. In the rotation process, the photosensitive member 72 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the charging unit 73, and then receives image exposure light from an image exposure unit such as slit exposure or laser beam scanning exposure. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor.
The formed electrostatic latent image is then developed with toner by the developing means 74. The developed toner image is sequentially transferred by the transfer unit to the transfer material fed from the paper feeding unit between the photoconductor and the transfer unit in synchronization with the rotation of the photoconductor. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor 72 after the image transfer is cleaned by removing the transfer residual toner by the cleaning means 75, and after being further discharged, it is repeatedly used for image formation.

(Image forming device)
For example, the image forming apparatus shown in FIGS. 10 and 11 can be used as the image forming apparatus in which the image forming method of the present invention is implemented.
In FIG. 10, a main body (100) includes an image writing unit (120Bk, 120C, 120M, 120Y), an image forming unit (130Bk, 130C, 130M, 130Y), and a paper feeding unit for performing color image formation by electrophotography. (140). Based on the image signal, image processing is performed by an image processing unit (not shown), and converted into black (Bk), cyan (C), magenta (M), and yellow (Y) color signals for image formation, It transmits to an image writing part (120Bk, 120C, 120M, 120Y). The image writing unit (120Bk, 120C, 120M, 120Y) is, for example, a laser scanning optical system including a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group (none of which are shown). Yes, it has four writing optical paths corresponding to the respective color signals, and performs image writing corresponding to the respective color signals to the image forming units (130Bk, 130C, 130M, 130Y).

  The image forming unit (130Bk, 130C, 130M, 130Y) includes photoconductors (210Bk, 210C, 210M, 210Y) for black, cyan, magenta, and yellow, and photoconductors (210Bk, 210C, 210M and 210Y) are usually OPC photoreceptors. Around each of the photoconductors (210Bk, 210C, 210M, 210Y), there are charging devices (215Bk, 215C, 215M, 215Y), and laser light exposure units from the image writing unit (120Bk, 120C, 120M, 120Y). , Developing devices for respective colors (200Bk, 200C, 200M, 200Y), primary transfer devices (230Bk, 230C, 230M, 230Y), cleaning devices (300Bk, 300C, 300M, 300Y), static eliminators (not shown), etc. Is arranged. The developing device (200Bk, 200C, 200M, 200Y) uses a two-component magnetic brush developing system. An intermediate transfer belt (220) is interposed between each photoconductor (210Bk, 210C, 210M, 210Y) and the primary transfer device (230Bk, 230C, 230M, 230Y), and the intermediate transfer belt (220). The toner images of the respective colors are sequentially transferred from the respective photoconductors so as to carry the toner images on the respective photoconductors.

  In some cases, a pre-transfer charger (502) as pre-transfer charging means is disposed outside the intermediate transfer belt (220) at a position after passing the primary transfer position of the final color and before passing the secondary transfer position. It is preferable. The pre-transfer charger (502) transfers the toner image before transferring the toner image on the intermediate transfer belt (220) transferred to the photosensitive member (210) in the primary transfer portion onto a transfer sheet as a transfer material. The toner image is uniformly charged to the same polarity as the toner image.

  The toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) includes a halftone portion and a solid portion, or includes a portion where the amount of toner overlap is different. Therefore, the charge amount may vary. Further, when the discharge amount generated in the gap adjacent to the downstream side of the primary transfer portion in the movement direction of the intermediate transfer belt causes variation in charge amount in the toner image on the intermediate transfer belt (220) after the primary transfer. There is also. Such variation in the charge amount in the same toner image lowers the transfer margin in the secondary transfer portion that transfers the toner image on the intermediate transfer belt (220) onto the transfer paper. Therefore, the toner image before being transferred onto the transfer paper by the pre-transfer charger (502) is uniformly charged to the same polarity as the toner image, thereby eliminating the variation in the charge amount in the same toner image. Improving the transfer margin.

  As described above, according to this embodiment, the toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) is uniformly charged by the pre-transfer charger (502), so that intermediate Even if there is a variation in the charge amount in the toner image on the transfer belt (220), the transfer characteristics in the secondary transfer portion can be made substantially constant across the portions of the toner image on the intermediate transfer belt (220). it can. Therefore, it is possible to suppress a decrease in transfer margin when transferring to transfer paper and to stably transfer a toner image.

  In the above-described embodiment, the amount of charge charged by the pre-transfer charger (502) varies depending on the moving speed of the intermediate transfer belt (220) that is an object to be charged. For example, if the moving speed of the intermediate transfer belt (220) is slow, the time during which the same portion of the toner image on the intermediate transfer belt (220) passes through the charging region by the pre-transfer charger (502) becomes longer, so growing. Conversely, when the moving speed of the intermediate transfer belt (220) is fast, the charge amount of the toner image on the intermediate transfer belt (220) becomes small. Accordingly, when the moving speed of the intermediate transfer belt (220) changes while the toner image on the intermediate transfer belt (220) passes through the charging position by the pre-transfer charger (502), the intermediate transfer is performed. It is desirable to control the pre-transfer charger (502) according to the moving speed of the belt (220) so that the charge amount with respect to the toner image does not change midway.

  The pre-transfer charger (502) surrounds the discharge wire (502a), the grid electrode (502b) interposed between the discharge wire (502a) and the intermediate transfer belt (220), and the discharge wire (502a). And a DC high voltage having the same polarity as the charging polarity of the toner image on the intermediate transfer belt (220) to the discharge wire (502a) by the power source (803) for the pre-transfer charger (502). Is applied and corona discharge occurs.

Conductive rollers (241), (242), and (243) are provided between the primary transfer devices (230Bk, 230C, 230M, and 230Y). After the transfer paper is fed from the paper feed unit (140), it is carried on the transfer belt (500) via the registration roller pair (160), and the intermediate transfer belt (220) and the transfer belt (500) are in contact with each other. The toner image on the intermediate transfer belt (220) is transferred to the transfer paper by the secondary transfer roller (600), and a color image is formed.
Then, the transfer paper after the image formation is conveyed to the fixing device (150) by the transfer belt (500), and the image is fixed to obtain a color image. The toner on the intermediate transfer belt (220) remaining without being transferred is removed from the belt by the intermediate transfer belt cleaning device (260).

  Since the toner polarity on the intermediate transfer belt (220) before transfer onto the transfer paper is the same negative polarity as that during development, a positive transfer bias voltage is applied to the secondary transfer roller (600), and the toner is transferred. It is transferred onto paper. The nip pressure at this portion affects the transfer property and greatly affects the fixability. Further, the toner on the intermediate transfer belt (220) remaining without being transferred is discharged and charged to the positive polarity side and charged from 0 to the positive side at the moment when the transfer paper and the intermediate transfer belt (220) are separated. Note that the toner image formed when the transfer paper is jammed or in the non-image area is not affected by the secondary transfer, and of course remains in the negative polarity.

  The thickness of the photosensitive layer is 30 μm, the beam spot diameter of the optical system is 50 × 60 μm, and the light quantity is 0.47 mW. The developing process is performed with the charging (exposure side) potential V0 of the photoreceptor (black) (210Bk) being −700 V, the post-exposure potential VL being −120 V, the developing bias voltage being −470 V, that is, the developing potential 350 V. The visible image of the toner (black) formed on the photoconductor (black) (210Bk) is then transferred (intermediate transfer belt and transfer paper) and completed as an image through a fixing process. First, all the colors are transferred from the primary transfer device (230Bk, 230C, 230M, 230Y) to the intermediate transfer belt (220), and then transferred to the transfer paper by applying a bias to another secondary transfer roller (600). Transcribed.

  The positively charged toner remaining on the intermediate transfer belt (220) is cleaned by a conductive fur brush (262) to which a negative voltage is applied. The method of applying a voltage to the conductive fur brush (262) is exactly the same as that of the conductive fur brush (261) except for the polarity. The toner remaining without being transferred is also almost cleaned by the two conductive fur brushes (261) and (262). Here, toner, paper powder, talc, and the like remaining without being cleaned by the conductive fur brush (262) are negatively charged by the negative voltage of the conductive fur brush (262). The next black primary transfer is a transfer using a positive voltage, and negatively charged toner or the like is attracted to the intermediate transfer belt (220) side, so that the transfer to the photoconductor (black) (210Bk) side can be prevented.

FIG. 11 shows another example of an image forming apparatus in which the image forming method of the present invention is carried out, and is a tandem indirect transfer type electrophotographic apparatus. In the figure, (100) is a copying apparatus main body, (200) is a paper feed table on which it is placed, (300) is a scanner mounted on the copying apparatus main body (100), and (400) is an automatic document feeder mounted thereon. (ADF). The copying machine main body (100) is provided with an endless belt-shaped intermediate transfer member (10) in the center.
As shown in FIG. 11, the intermediate transfer member (10) is wound around three support rollers (14), (15), and (16) in the illustrated example so that it can be rotated and conveyed clockwise in the drawing.
In this illustrated example, an intermediate transfer body cleaning device (17) for removing residual toner remaining on the intermediate transfer body (10) after image transfer is provided on the left of the second support roller (15) among the three.

Further, among the three, the intermediate transfer member (10) stretched between the first support roller (14) and the second support roller (15) has yellow, cyan and magenta along the transport direction. The four black image forming means (18) are arranged side by side to constitute a tandem image forming apparatus (20).
An exposure device (21) is further provided on the tandem image forming device (20) as shown in FIG. On the other hand, a secondary transfer device (22) is provided on the side opposite to the tandem image forming device (20) with the intermediate transfer member (10) interposed therebetween. In the illustrated example, the secondary transfer device (22) includes a secondary transfer belt (24), which is an endless belt, spanned between two rollers (23), and the second transfer device (22) passes through an intermediate transfer member (10). 3 is pressed against the support roller (16), and the image on the intermediate transfer body (10) is transferred to the sheet.

Next to the secondary transfer device (22), a fixing device (25) for fixing the transferred image on the sheet is provided. The fixing device (25) is configured by pressing a pressure roller (27) against a fixing belt (26) which is an endless belt.
The secondary transfer device (22) described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device (25). Of course, as the secondary transfer device (22), a transfer roller or a non-contact charger may be arranged, but in such a case, it is difficult to provide this sheet conveyance function together.
In the illustrated example, a sheet is placed under such a secondary transfer device (22) and a fixing device (25) so as to record an image on both sides of the sheet in parallel with the tandem image forming device (20). A sheet inverting device (28) for inverting is provided.

Now, when making a copy using this color electrophotographic apparatus, the document is set on the document table (30) of the automatic document feeder (400). Alternatively, the automatic document feeder (400) is opened, a document is set on the contact glass (32) of the scanner (300), and the automatic document feeder (400) is closed and pressed by it.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32), and then the other contact glass (32). When a document is set on the scanner, the scanner (300) is immediately driven to travel on the first traveling body (33) and the second traveling body (34). Then, the first traveling body (33) emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body (34) and reflected by the mirror of the second traveling body (34). Then, the image is placed in the reading sensor (36) through the imaging lens (35) and the content of the original is read.

  When a start switch (not shown) is pressed, one of the support rollers (14), (15), and (16) is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. The transfer body (10) is rotated and conveyed. At the same time, the individual image forming means (18) rotates the photoreceptor (40) to form monochrome images of black, yellow, magenta, and cyan on each photoreceptor (40). Then, along with the conveyance of the intermediate transfer member (10), these monochrome images are sequentially transferred to form a composite color image on the intermediate transfer member (10).

On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers (42) of the paper feed table (200) is selectively rotated, and one of paper feed cassettes (44) provided in multiple stages in the paper bank (43). The sheet is fed out from the sheet, separated one by one by a separation roller (45), put into a sheet feeding path (46), and conveyed by a conveying roller (47) to a sheet feeding path (48) in the copying machine main body (100). Guide and stop against the registration roller (49).
Alternatively, the sheet feeding roller (50) is rotated to feed out the sheets on the manual feed tray (51), separated one by one by the separation roller (52), and placed in the manual sheet feeding path (53). ) And stop.

Then, the registration roller (49) is rotated in time with the composite color image on the intermediate transfer member (10), and the sheet is fed between the intermediate transfer member (10) and the secondary transfer device (22). The image is transferred by the next transfer device (22) and a color image is recorded on the sheet.
The sheet after the image transfer is conveyed by the secondary transfer device (22) and sent to the fixing device (25). The fixing device (25) applies heat and pressure to fix the transferred image, and then the switching claw. It is switched at (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55) and put into the sheet reversing device (28), where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then the paper discharge tray (56) is discharged by the discharge roller (56). 57) Drain up.

On the other hand, the intermediate transfer member (10) after the image transfer is removed by the intermediate transfer member cleaning device (17) to remove residual toner remaining on the intermediate transfer member (10) after the image transfer, and the tandem image forming device (20). To prepare for image formation again.
Here, the registration roller (49) is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

The present invention relates to the following toner (1), and includes the following (2) to (8) as embodiments.
(1) In a toner containing a binder resin and a release agent, the toner has an average circularity of 0.96 to 0.99, and a width (A) and a depth (B) on the surface of the toner. A toner, wherein a ratio of toner particles having one or more concave portions having a ratio (A / B) of 0.3 to 0.9 is 10 to 50% by number.
(2) The toner according to (1), wherein the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.15. .
(3) The toner according to (1) or (2), wherein silica having a primary average particle size of 80 to 500 nm is added to the surface of the toner.
(4) a droplet forming step of forming a droplet by discharging a toner composition solution in which a toner composition containing at least a binder resin, a colorant and a release agent is dissolved or dispersed in an organic solvent; The toner according to any one of (1) to (3), wherein the toner is produced through a drying process in which the droplets are dried and solidified.
(5) A developer comprising the toner according to any one of (1) to (4) and a carrier.
(6) an image carrier, a charging unit for charging the image carrier, a latent image forming unit for forming an electrostatic latent image on the image carrier, and an electrostatic latent image on the image carrier to be toner In an image forming apparatus comprising a developing means for developing by
An image forming apparatus, wherein the toner according to any one of (1) to (4) is used as the toner replenished to the developing means.
(7) The image forming apparatus according to (6), wherein a plurality of the image carriers are provided, and the toner images formed on the image carriers are sequentially transferred to a transfer medium.
(8) an image carrier, a charging unit for charging the image carrier, a developing unit for developing a latent image on the image carrier, and a cleaning unit for cleaning transfer residual toner remaining on the image carrier. The image forming apparatus including the image carrier, at least one selected from the charging unit and the cleaning unit, and the developing unit are integrally configured to be detachable from the main body of the image forming apparatus. In the cartridge, the toner used in the developing means is the toner described in any one of (1) to (4).

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, this invention is not limited to the Example and comparative example which are illustrated here. In addition, the part in an Example represents a mass part.

(Preparation of Toner 1)
[Preparation of colorant dispersion]
First, a carbon black dispersion as a colorant was prepared.
Carbon black (Rega L400; manufactured by Cabot) 18 parts and pigment dispersant 3 parts were primarily dispersed in 79 parts of ethyl acetate using a mixer having stirring blades. The obtained primary dispersion was finely dispersed by a strong shearing force using a dyno mill to prepare a secondary dispersion from which aggregates were completely removed. Furthermore, [Carbon Black Dispersion 1] was prepared by passing through a polytetrafluoroethylene (PTFE) filter (Fluorinert Membrane Filter FHLP09050, Nihon Millipore Corporation) having 0.45 μm pores and dispersing to the submicron region. .

[Synthesis of binder resin]
In a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 0.7 mol of bisphenol A propylene oxide adduct and bisphenol A ethylene oxide adduct 0. 7 mol was added as a carboxylic acid component, 1.0 mol of terephthalic acid, and tin octylate was added as an esterification catalyst, and subjected to a condensation polymerization reaction at 190 ° C. for 5 hours in a nitrogen atmosphere. Thereafter, 0.07 mol of trimellitic acid was added, the temperature was raised to 210 ° C., the mixture was reacted for 2 hours, and further reacted at 8 KPa for 1 hour to synthesize [Polyester Resin 1]. The resin had a weight average molecular weight of 23,000 and a glass transition point of 56 ° C.
The weight average molecular weight Mw was determined by measuring the THF-soluble content of the binder resin with a GPC (gel permeation chromatography) measuring device GPC-150C (manufactured by Waters). KF801-807 (manufactured by Shodex) was used for the column, and RI (refractive index) detector was used for the detector.

[Preparation of toner composition liquid]
In 676.7 parts of ethyl acetate, LW-13 as a release agent (melting point: 70.3 ° C., crystallization temperature: 64.1 ° C., a synthetic ester wax that can be dissolved in ethyl acetate at 40 ° C. by 3.6%, 20 parts of Seiki Co., Ltd., 10 parts of diethylene glycol stearate (melting point 62 ° C.) as a fixing aid, and 263.3 parts of [Polyester resin 1] as a binder resin are mixed at 40 ° C. with stirring blades Dissolved using a mixer with In the toner solution after dissolution, no pigment agglomerates, fixing aids and release agents were dissolved. Further, 100 parts of [Carbon Black Dispersion 1] were mixed and stirred for 10 minutes to prepare [Toner Composition 1].

[Preparation of toner base particles]
[Toner Composition Liquid 1] was discharged using the toner manufacturing apparatus shown in FIGS. 1, 2, and 6 by a liquid droplet ejection head using the liquid column resonance principle under the following conditions. Thereafter, the liquid droplets were dried and solidified, collected by a cyclone, and then secondarily dried at 38 ° C. for 48 hours, thereby producing [Toner Base Particles 1].

[Liquid column resonance conditions]
Resonance mode: N = 2
Length between both ends in the longitudinal direction of the liquid column resonance liquid chamber: L = 1.8 mm
Height of end of frame on liquid common supply path side of liquid column resonance liquid chamber: h1 = 80 μm
The height of the communication port of the liquid column resonance liquid chamber: h2 = 40 μm

[Toner base particle preparation conditions]
Dispersion specific gravity: ρ = 1.1 g / cm ³
Discharge port shape: perfect circle Discharge port diameter: 7.5μm
Number of discharge ports: 4 per liquid column resonance liquid chamber Minimum distance between adjacent discharge ports: 130 μm (all equally spaced)
Dry air temperature: 40 ° C
Applied voltage: 10.0V
Drive frequency: 385 kHz

  100 parts of the obtained [Toner Base Particle 1], 1.0 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 15 nm, and titanium oxide fine powder having an average particle diameter of 15 nm (isobutyltrimethoxysilane treatment) 0.5 part was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at a peripheral speed of 30 m / sec for 30 seconds and subjected to a rest for 1 cycle, and then sieved with a mesh having an opening of 35 μm [toner 1] was produced.

(Preparation of Toner 2)
In the production of [Toner 1], [Toner 2] was produced in the same manner as [Toner 1] except that the blending amount of diethylene glycol stearate in the toner composition preparation step was changed from 10 parts to 15 parts.

(Preparation of Toner 3)
In the production of [Toner 1], [Toner 3] was produced in the same manner as [Toner 1] except that the blending amount of diethylene glycol stearate in the step of preparing the toner composition liquid was changed from 10 parts to 20 parts.

(Preparation of Toner 4)
Toner 4 was prepared in the same manner as in Toner 1 except that [Binder Resin Synthesis] was changed as follows in the preparation of [Toner 1].

[Synthesis of binder resin]
In a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 0.5 mol of bisphenol A propylene oxide adduct and bisphenol A ethylene oxide adduct 0. Five moles were added as a carboxylic acid component, 0.9 mole of terephthalic acid and tin octylate as an esterification catalyst, and subjected to a condensation polymerization reaction at 190 ° C. for 5 hours in a nitrogen atmosphere. Thereafter, 0.07 mol of trimellitic acid was added, the temperature was raised to 210 ° C., the mixture was reacted for 2 hours, and further reacted at 8 KPa for 1 hour to synthesize [Polyester Resin 2]. This resin had a weight average molecular weight of 60,000 and a glass transition point of 59 ° C.

(Preparation of Toner 5)
In the production of [Toner 4], the blending amount of diethylene glycol stearate in the toner composition preparation step was changed from 10 parts to 15 parts, and silica fine powder (hexamethyldisilazane treatment) having an average particle size of 100 nm was further added as an external additive. ) [Toner 5] was prepared in the same manner as [Toner 4] except that 0.8 part was added.

(Production of Toner 6)
In the production of [Toner 5], 0.8 parts of silica fine powder having an average particle diameter of 100 nm (hexamethyldisilazane treatment) as an external additive is 0.8 parts of silica fine powder having an average particle diameter of 480 nm (hexamethyldisilazane treatment). [Toner 6] was produced in the same manner as [Toner 5] except that the toner was changed to the part.

(Production of toner 7)
In the production of [Toner 5], [Toner 6] was produced in the same manner as [Toner 5] except that the blending amount of diethylene glycol stearate in the step of preparing the toner composition liquid was changed from 15 parts to 20 parts.

(Production of toner 8)
[Toner 8] was prepared in the same manner as [Toner 5] except that 15 parts of diethylene glycol stearate was changed to 20 parts of glycerin distearate in the preparation process of toner composition. did.

(Preparation of Toner 9)
In the preparation of [Toner 1], [Toner 9] was prepared in the same manner as [Toner 1] except that 10 parts of diethylene glycol stearate in the toner composition preparation step was changed to 5 parts of ethylene glycol dibehenate (melting point: 84 ° C.). Produced.

(Production of Toner 10)
In the production of [Toner 1], [Toner 10] was produced in the same manner as [Toner 1] except that 10 parts of diethylene glycol stearate in the toner composition preparation step was changed to 10 parts of [Crystalline Polyester 1] described below. did.

-Crystalline polyester 1-
Into a 5-liter four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, 2,320 g of 1,10-decanedioic acid, 1,430 g of 1,8-octanediol, and 4.9 g of hydroquinone The mixture was reacted at 200 ° C. for 10 hours, heated to 230 ° C. and reacted for 3 hours, and further reacted at 8.3 kPa for 4 hours to obtain [Crystalline Polyester 1] (melting point 70 ° C.).

(Production of Toner 11)
[Toner 1] was prepared in the same manner as [Toner 1] except that the fixing aid in the toner composition liquid preparation step was omitted.

(Preparation of Toner 12)
[Toner 12] was produced in the same manner as [Toner 11] except that 0.8 part of silica fine powder (hexamethyldisilazane treatment) having an average particle diameter of 100 nm was further added as an external additive.
For [Toner 1] to [Toner 12] produced as described above, the constituent components of the toner are shown in Table 1, and the physical properties of the toner are shown in Table 2.

(Preparation of Toner 13)
[Toner 13] was prepared in the same manner as [Toner 1] except that the amount of diethylene glycol stearate in the toner composition preparation step was changed from 10 parts to 25 parts in the preparation of [Toner 1].

<Career>
Next, a specific example of manufacturing the carrier used for evaluation will be described. The carrier used in the present invention is not limited to these examples.
Acrylic resin solution (solid content 50% by mass) 21.0 parts Guanamin solution (solid content 70% by mass) 6.4 parts Alumina particles [0.3 μm, specific resistance 1014 (Ω · cm)] 7.6 parts Silicone resin solution 65.0 parts [Solid content 23% by mass (SR2410: manufactured by Toray Dow Corning Silicone)]
Aminosilane 1.0 part [Solid content 100% by mass (SH6020: manufactured by Toray Dow Corning Silicone)]
60 parts of toluene 60 parts of butyl cellosolve was dispersed with a homomixer for 10 minutes to obtain a blend coating film forming solution of an acrylic resin and a silicone resin containing alumina particles. A fired ferrite powder [(MgO) 1.8 (MnO) 49.5 (Fe2O3) 48.0: average particle size; 35 μm] was used as the core material, and the coating film forming solution was applied to the surface of the core material with a film thickness of 0. It was applied and dried by a Spira coater (Okada Seiko Co., Ltd.) so as to be 15 μm. The obtained carrier was baked by standing in an electric furnace at 150 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 106 μm to obtain a carrier. The measurement of the binder resin film thickness was performed by observing the cross section of the carrier with a transmission electron microscope so that the coating film covering the carrier surface could be observed. Thus, a carrier having a weight average particle diameter of 35 μm was obtained.

<Preparation of two-component developer>
Using the above [Toner 1] to [Toner 11] and the above ferrite carrier, 7 parts of toner with 100 parts of carrier are uniformly mixed and charged using a type of tumbler mixer in which the container rolls and stirs. An agent was prepared.

<Evaluation method>
The prepared developer is set in an image forming apparatus (RICOHPro C751EX manufactured by Ricoh Co., Ltd.), and in a normal temperature and normal humidity (25 ° C., 60% RH) environment, Ricoh type 6000 <70 W> paper (A4, T-th) A solid pattern with a toner adhesion amount of 0.85 ± 0.10 mg / cm 2 was output. The fixing temperature was 140 ° C.

(Cleanability)
After running 1,000 sheets and 100,000 sheets, remove the photoconductors, and collect the transfer residual toner on the photoconductor that passed through the cleaning blade with Nitto Denko's Printerac C (thickness 25 μm) and paste it on a blank sheet. Using an 938 spectrodensitometer (manufactured by X-Rite), an average value was calculated by measuring 10 IDs with an observation light source D50 and a viewing angle of 2 °.
The difference from the blank was evaluated as ◎, less than 0.005, ◯ from 0.005 to less than 0.010, Δ from 0.010 to less than 0.015, and x from 0.015 or more.
◎ and ○ indicate good cleaning properties.

(Chile, dot defect, fine line reproducibility evaluation)
Ten A4 evaluation charts for evaluating dust, dot defects, and fine line reproducibility were continuously printed after finishing 1,000 sheets and 100,000 sheets, respectively. Chile and dot defects were evaluated by observing dot images with a magnifying glass and comparing them using limit samples, and comprehensively evaluating the image quality rank of minute dots. For fine lines, the image quality rank was comprehensively evaluated by visual observation of fine line images using limit samples.
The image quality rank is 5 levels, 5 for an image with no dust and dot defects and good fine line reproducibility, and 1 for 5 levels with 1 for poor reproducibility of dust, dot defects and fine lines. It is evaluated one by one. Finally, an average value of 10 sheets is obtained as a comprehensive evaluation, and an average value of 4 or more is assumed to have good reproducibility of dust, dot defects, and fine lines.

(Solid uniformity)
After running 1,000 sheets and 100,000 sheets, A3 all-solid images were output, and the image densities at four corners and one center of A3 paper were measured. The image density was measured using a gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. under the condition of an incident angle of 60 °.
Solid uniformity = (maximum value of image density−minimum value of image density) × 100 (%)
Average image density at 5 locations
Rank 5: less than 15%
Rank 4: 15% to less than 30% Rank 3: 30% to less than 50% Rank 2: 50% to less than 70% Rank 1: 70% or more
The results of the evaluation are shown in Table 3.

1: Toner manufacturing apparatus 2: Droplet discharge means 6: Toner composition liquid supply port 7: Toner composition liquid flow path 8: Toner composition liquid discharge port 9: Elastic plate 10: Liquid column resonance Droplet discharge unit 11: Liquid column resonance Droplet discharge means 12: Air flow passage 13: Raw material container 14: Toner composition liquid 15: Liquid circulation pump 16: Liquid supply pipe 17: Liquid common supply path 18: Liquid column resonance flow path 19: Discharge port 20: Vibration generating means 21: droplet 22: liquid return pipe 23: coalescence droplet 24: nozzle angle 60: dry collection means 61: chamber 62: toner collection means 63: toner storage section 64: conveyance air flow inlet 65: conveyance air flow exhaust Exit 71 Process cartridge 72 Photoconductor 73 Charging means 74 Developing means 75 Cleaning means P1: Liquid pressure gauge P2: In-chamber pressure gauge

JP-A-7-209952 JP 2000-077551 Japanese Patent No. 3640918 JP-A-6-250439 JP 2003-262976 A JP 2003-280236 A Japanese Patent Laid-Open No. 2003-262977

Claims (8)

In a toner containing a binder resin and a release agent,
The average circularity of the toner is 0.96 to 0.99,
The ratio of toner particles having one or more recesses having a ratio (A / B) of width (A) to depth (B) of 0.3 to 0.9 on the surface of the toner is 10 to 50% by number. Toner characterized by being.   2. The toner according to claim 1, wherein the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.15.   The toner according to claim 1, wherein silica having a primary average particle size of 80 to 500 nm is added to the surface of the toner.   A droplet forming step of forming a droplet by discharging a toner composition solution in which a toner composition containing at least a binder resin, a colorant and a release agent is dissolved or dispersed in an organic solvent; and the formed droplet The toner according to claim 1, wherein the toner is produced through a drying step of drying and solidifying the toner.   A developer comprising the toner according to claim 1 and a carrier. An image carrier, charging means for charging the image carrier, latent image forming means for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image on the image carrier with toner In an image forming apparatus comprising a developing unit,
An image forming apparatus using the toner according to claim 1 as the toner replenished to the developing means.   The image forming apparatus according to claim 6, wherein a plurality of the image carriers are provided, and toner images formed on the image carriers are sequentially transferred to a transfer medium. An image comprising an image carrier, a charging unit for charging the image carrier, a developing unit for developing a latent image on the image carrier, and a cleaning unit for cleaning the transfer residual toner remaining on the image carrier. In a process cartridge used in a forming apparatus, wherein at least one selected from the image carrier, the charging unit, and the cleaning unit and the developing unit are integrated and detachable from the main body of the image forming apparatus.
The process cartridge according to claim 1, wherein the toner used in the developing unit is the toner according to claim 1.