JP5354274B2 - Toner, developer using the toner, process cartridge, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner that responds to a low temperature fixing system, shows good offset resistance and forms high quality images having good sharpness for a long period of time without contaminating a fixing device or images, and to provide a developer using the toner, a toner container, a process cartridge and an image forming method. <P>SOLUTION: The toner contains at least a polyester resin as a binder resin, a colorant, a release agent and a fixing assistant component, wherein the fixing assistant component is a dibasic acid ester compound prepared by esterification of a divalent carboxylic acid and a monohydric aliphatic alcohol, the number of carbon atoms in the divalent carboxylic acid is &ge;2 and &le;6, and the melting point of the dibasic acid ester compound is &ge;60&deg;C and lower than 100&deg;C. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, and the like, a developer using the toner, a container containing toner, a process cartridge, and an image forming method.

Image formation by electrophotography, electrostatic recording, electrostatic printing, etc. is generally performed on an electrostatic latent image on an electrostatic latent image carrier (hereinafter also referred to as “photosensitive member” or “electrophotographic photosensitive member”). The electrostatic latent image is developed with a developer to form a visible image (toner image), and then the visible image is transferred onto a recording medium such as paper and fixed to obtain a fixed image. It is performed by a series of processes.
Examples of the developer include a one-component developer using a magnetic toner or a non-magnetic toner alone, and a two-component developer composed of a toner and a carrier.

  As a fixing method in the electrophotographic method, a heating heat roller method in which a heating roller is directly pressed against a toner image on a recording medium and fixed is widely used from the viewpoint of energy efficiency. The heating heat roller system requires a large amount of power for fixing. Therefore, various studies have been made to reduce the power consumption of the heating roller from the viewpoint of energy saving. For example, a method is generally used in which the output of the heater for the heating roller is weakened when the image is not output and the output of the heater is increased to increase the temperature of the heating roller when the image is output.

  However, in this case, in order to raise the temperature of the heating roller to the temperature necessary for fixing from the sleep time, a waiting time of about several tens of seconds is required, and this waiting time becomes a stress for the user. In addition, when the image is not output, it is desired to suppress power consumption by completely turning off the heater. In order to achieve these requirements, it is necessary to lower the fixing temperature of the toner itself and lower the fixing temperature of the toner when it can be used.

  The toner used in the developer is required to have excellent low-temperature fixability and storage stability (blocking resistance) with the development of electrophotographic technology, and has been generally used as a binder resin for toner. Various attempts have been made to use a polyester resin having a higher affinity with a recording medium or the like than a styrene-based resin and excellent in low-temperature fixability. For example, a toner containing a linear polyester resin that defines physical properties such as molecular weight (see Patent Document 1), a toner containing a non-linear cross-linked polyester resin using a rosin as an acid component (see Patent Document 2), Etc. have been proposed.

  In recent years, in order to further increase the speed and energy saving of the image forming apparatus, the conventional binder resin for toner is still insufficient for the market demand, shortening the fixing time in the fixing process, and Due to the lowering of the heating temperature by the fixing means, it is very difficult to maintain a sufficient fixing strength.

  A toner containing a polyester resin using a rosin as in Patent Document 2 is excellent in low-temperature fixability and excellent in pulverization, and thus has an advantage of improving toner productivity in the pulverization method. Further, by using 1,2-propanediol, which is a branched chain alcohol having 3 carbon atoms, as the alcohol component, the low-temperature fixability is improved while maintaining the offset resistance as compared with the alcohol having 2 or less carbon atoms. This is effective in preventing a decrease in storage stability accompanying a decrease in glass transition temperature as compared with branched chain alcohols having 4 or more carbon atoms. By using such a polyester resin as a binder resin for toner, it is possible to fix at a low temperature and to improve the storage stability.

  However, the demand for energy saving tends to become more and more severe in the future, and the use of a polyester resin with excellent low-temperature fixability tends to improve the low-temperature fixability compared to the conventional one. It is difficult to sufficiently meet the demand for energy saving only by using it.

  In recent years, attempts have been made to improve low-temperature fixability by introducing a fixing auxiliary component into toner (see Patent Document 3). Patent Document 3 proposes a toner that achieves both heat-resistant storage stability and low-temperature fixability by allowing a fixing auxiliary component to be present as a crystalline domain in the toner. However, in recent years, with the speeding up of machines, it is desirable that toners satisfy high demands for energy saving as well as high durability. At present, it is difficult to sufficiently meet these demands, and further improvements are made. The reality is that development is desired.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is compatible with a low-temperature fixing system, has good offset resistance, does not contaminate the fixing device and the image, and can form a high-quality image with good sharpness over a long period of time. Another object of the present invention is to provide a developer using the toner, a container containing toner, a process cartridge, and an image forming method.

The present invention is solved by the following (1) to (18).
(1) "at least, a binder resins, a colorant, a releasing agent, a toner comprising a fixing auxiliary component, wherein the includes a polyester resin binder resin as a main component, the fixing auxiliary component A dibasic acid ester compound obtained by esterifying a divalent carboxylic acid and a monovalent aliphatic alcohol, wherein the divalent carboxylic acid has 2 to 6 carbon atoms, and the dibasic acid ester compound has a melting point of 60. Toner having a temperature of not lower than 100 ° C. and lower than 100 ° C. ”;
(2) “The toner according to item (1), wherein the acid value of the dibasic acid ester compound is 0.1 mgKOH / g or more and less than 100 mgKOH / g”;
(3) “The toner according to (1) or (2), wherein the divalent carboxylic acid is adipic acid”;
(4) “Toner according to any one of (1) to (3) above, wherein the monohydric aliphatic alcohol is a linear saturated aliphatic alcohol”;
(5) “The toner according to item (4), wherein the linear saturated aliphatic alcohol has 10 to 24 carbon atoms”;
(6) “The toner according to any one of (1) to (5) above, wherein the releasing agent is a hydrocarbon wax having a melting point of 60 ° C. or higher and lower than 90 ° C.”;
(7) The toner according to any one of (1) to (6) above, wherein at least one acid value of the polyester resin is 5 mg KOH / g or more and less than 40 mg KOH / g. ";
(8) “The toner according to item (7), wherein the acid value of at least one or more of the polyester resins is further 10 mgKOH / g or more and less than 30 mgKOH / g”;
(9) “The toner according to (7) or (8) above, wherein at least one hydroxyl value of the polyester resin is 5 mgKOH / g or more and less than 100 mgKOH / g”;
(10) “At least one kind of hydroxyl value of the polyester resin is further 20 mgKOH / g or more and less than 60 mgKOH / g,” in any one of the above items (1) to (9) Described toner ";
(11) The Tg of at least one kind of polyester resin contained in the toner is 55 ° C. or higher and lower than 80 ° C. toner";
(12) “Polyester resin after adding 10 parts by weight of a fixing aid to 90 parts by weight of the polyester resin and heating at 150 ° C. with a glass transition temperature of at least one polyester resin contained in the toner as Tgr. The toner according to any one of the above items (1) to (11), wherein the following formula, Tgr−Tgr ′> 10 ° C.
(13) The toner according to any one of (1) to (12), wherein the content of the fixing auxiliary component in the toner is 3% by weight or more and less than 20% by weight. ;
(14) "The toner according to any one of (1) to (13) above, wherein the toner is produced in an aqueous medium";
(15) "Developer comprising the toner according to any one of (1) to (14)";
(16) “Toner-containing container filled with the toner according to any one of items (1) to (14)”;
(17) “At least a latent electrostatic image bearing member and developing means for developing a latent electrostatic image formed on the latent electrostatic image bearing member with toner to form a visible image, A process cartridge removable from the main body of the forming apparatus, wherein the toner is the toner according to any one of items (1) to (14);
(18) “An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, and a developing step of developing the electrostatic latent image with toner to form a visible image; An image forming method including at least a transfer step of transferring the visible image to a recording medium and a fixing step of fixing the transfer image transferred to the recording medium, wherein the toner is the item (1) to An image forming method comprising the toner according to any one of Items (14).

According to the present invention, conventional problems can be solved, low-temperature fixing systems are compatible, offset resistance is good, fixing devices and images are not contaminated, and high-quality images with good sharpness are obtained. It is possible to provide a toner that can be formed over a long period of time, a developer using the toner, a container containing the toner, a process cartridge, and an image forming method.

It is a figure which shows an example of the image forming apparatus of this invention. It is a figure which shows the other example of the image forming apparatus of this invention. FIG. 3 is a diagram showing a tandem developing device of FIG. 2. It is a figure which shows an example of the process cartridge of this invention.

(toner)
The toner of the present invention contains at least a binder resin, a release agent, and a fixing auxiliary component, and further contains other components as necessary.

<Fixing auxiliary component>
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.

[Dibasic acid ester compound]
The dibasic acid ester compound of the present invention has the following structure in which a divalent carboxylic acid having the following structural formula and a monovalent aliphatic alcohol are esterified.

(Divalent carboxylic acid)
Fumaric acid: HOOC- (CH2) n-COOH
n = 0 or more and 4 or less

(Monohydric aliphatic alcohol)
R1-OH
R1: Saturated or unsaturated carbon hydrogen group

[Dibasic acid ester compound]
R2-COO-R1-COO-R3
R2-COO-R1-COOH
R1: a linear carbon hydrogen group having 0 to 4 carbon atoms R2: a saturated or unsaturated carbon hydrogen group R3: a saturated or unsaturated carbon hydrogen group

A compound having the above structure and having a melting point of 60 to 100 ° C. is used as a fixing auxiliary component of the present invention. Preferably it is 75-100 degreeC, More preferably, it is 75-95 degreeC. When the melting point is lower than 60 ° C., the heat resistant storage stability of the toner is deteriorated. When the melting point is higher than 100 ° C., the low-temperature fixability cannot be sufficiently obtained.
The dibasic acid ester compound may be esterified with a plurality of types of monohydric aliphatic alcohols, and the dibasic acid ester may be either a diester or a monoester, or a mixture thereof.

  The dibasic acid ester compound used as a fixing auxiliary component in the present invention contains an ester group and a carboxyl group as polar groups, so that it has moderate compatibility with the polyester resin that is the main component of the toner (the binder resin and the complete phase at the time of toner production). It melts into a single phase and precipitates in the toner particles as a crystalline domain, but has a compatibility that melts quickly by heating during toner fixing and softens the binder resin quickly) It is possible to exhibit low-temperature fixability by rapidly melting and softening the binder resin quickly. In addition, by using a divalent carboxylic acid having 2 to 6 carbon atoms and a monovalent aliphatic alcohol, the sharp melt property of the dibasic acid ester compound is improved. By softening the binder resin quickly, Low temperature fixability can be exhibited.

  Of the linear divalent carboxylic acids, adipic acid or fumaric acid is preferable, and adipic acid is more preferable. Since adipic acid has 6 carbon atoms and fumaric acid has 4 carbon atoms, it has excellent compatibility with the polyester resin, which is the main component of the toner. By quickly softening, low temperature fixability can be exhibited.

  In addition, when these divalent carboxylic acids having 2 to 6 carbon atoms and a linear aliphatic alcohol are used, the crystallinity of the dibasic ester compound is improved, so that the heat resistant storage stability is excellent, and further in the developing machine. Since a robust toner can be obtained against stress such as stirring, a high-quality image can be obtained over a long period of time.

  Of the linear monohydric aliphatic alcohols, saturated aliphatic alcohols are preferable, and further, the number of carbon atoms is preferably 10 or more and 24 or less. By using saturated aliphatic alcohol, crystallinity is improved, heat-resistant storage stability is excellent, and a robust toner can be obtained against stress such as stirring in the developing machine. Can be obtained. Examples of linear monohydric aliphatic alcohols include dodecanoic alcohol, lauryl alcohol, palmityl alcohol, stearyl alcohol, eicosane alcohol, and behenyl alcohol.

  When the number of carbon atoms is less than 10, the crystallinity of the dibasic acid ester compound is lowered and the heat resistant storage stability may be inferior. When the number of carbon atoms is larger than 24, compatibility with the polyester resin is deteriorated, and sufficient low-temperature fixability may not be obtained.

  Moreover, it is preferable that the acid value of a dibasic acid ester compound is 0.1 mgKOH / g or more and less than 100 mgKOH / g. When the acid value is less than 0.1 mg KOH / g, the compatibility with heating to the polyester resin is not sufficient, and thus the effect for low-temperature fixing may not be sufficiently obtained. On the other hand, when the hydroxyl value is 100 mgKOH / g or more, there is a risk that the charging characteristics of the toner at high temperature and high humidity are deteriorated.

  The acid value was measured using a potentiometric automatic titrator DL-53 Titrator (manufactured by METTLER TOLEDO), electrode DG113-SC (manufactured by METTLER TOLEDO) and analysis software LabX Light Version 1.000.000. The At this time, the apparatus is calibrated using a mixed solvent of 120 ml of toluene and 30 ml of ethanol, the measurement temperature is 23 ° C., and the measurement conditions are as follows.

Still
Speed [%] 25
Time [s] 15
EQP titration
Titrant / Sensor
Titrant CH3ONa
Concentration [mol / L] 0.1
Sensor DG115
Unit of measurement mV
Predispensing to volume
Volume [mL] 1.0
Wait time [s] 0
Titrant addition Dynamic
dE (set) [mV] 8.0
dV (min) [mL] 0.03
dV (max) [mL] 0.5
Measurement mode Equilibrium controlled
dE [mV] 0.5
dt [s] 1.0
t (min) [s] 2.0
t (max) [s] 20.0
Recognition
Threshold 100.0
Steppes jump only No
Range No
Tendency None
Termination
at maximum volume [mL] 10.0
at potential No
at slope No
after number EQPs Yes
n = 1
comb. termination conditions No
Evaluation
Procedure Standard
Potential 1 No
Potentialial 2 No
Stop for revaluation No

Specifically, the measurement is performed as follows based on the measurement method described in JIS K0070-1992. First, 0.5 g of a sample is added to 120 ml of toluene and dissolved by stirring at room temperature (23 ° C.) for about 10 hours, and then 30 ml of ethanol is added to obtain a sample solution. Next, by titrating with a pre-standardized 0.1N potassium hydroxide alcohol solution, a titration amount X [ml] is obtained, and an acid value is obtained from the following equation.
However, N is a factor of the alcohol solution of 0.1N potassium hydroxide.

The fixing auxiliary component exists as a crystalline domain in the toner, and has a characteristic of being compatible with the resin when heated.
In order to confirm that the fixing auxiliary component has crystallinity, the crystalline retention state (compatible or incompatible) can be measured from an X-ray diffraction chart.

  Specifically, whether the auxiliary fixing component has crystallinity in the toner can be confirmed by a crystal analysis X-ray diffractometer (manufactured by X'Pert MRDX'Pert MRD Phillips). First, a fixing auxiliary component alone is ground in a mortar to prepare a sample powder, and the obtained sample powder is uniformly applied to a sample holder. Thereafter, a sample holder is set in the diffractometer and measurement is performed to obtain a diffraction spectrum of a fixing auxiliary component. Next, toner powder is applied to the holder, and measurement is performed in the same manner. It is possible to identify the fixing auxiliary component contained in the toner from the diffraction spectrum of the fixing auxiliary component obtained in advance. Moreover, in the said apparatus, the change of the diffraction spectrum at the time of changing temperature with an attached heating unit is measurable. Using the same unit, it is possible to determine the proportion of compatible and incompatible components in the resin before and after heating of the fixing auxiliary component by changing the peak area of the X-ray diffraction spectrum derived from the fixing auxiliary component at room temperature and 150 ° C. The larger the rate of change of the peak area derived from the auxiliary fixing component before and after the heating, the more the compatibilization with the toner resin proceeds by the heating at the time of fixing.

  The dispersion diameter of the fixing auxiliary component is, for example, preferably 10 nm to 3 μm, more preferably 50 nm to 1 μm, in the maximum direction. When the dispersion diameter is less than 10 nm, the heat-resistant storage stability may be inferior due to an increase in the contact surface area between the fixing auxiliary component and the binder resin. When the dispersion diameter exceeds 3 μm, Insufficient compatibility with the binder resin may result in poor low temperature fixability.

  The method for measuring the dispersion diameter of the fixing auxiliary component is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the toner is embedded in an epoxy resin and cut into ultrathin sections of about 100 nm. After dyeing with ruthenium, observation is performed with a transmission electron microscope (TEM) at a magnification of 10,000 times, a photograph is taken, and the photograph is evaluated to observe the dispersion state of the fixing auxiliary component. The diameter can be measured. In order to identify the fixing auxiliary component and the release agent in the toner, the toner is obtained by confirming in advance the contrast difference obtained by dyeing the fixing auxiliary component and the release agent in the same manner with ruthenium tetroxide. It can be identified by the contrast difference between the fixing auxiliary component and the release agent.

  In the present invention, the glass transition temperature of the polyester resin is Tgr, and the glass transition temperature of the polyester resin after adding 10 parts by mass of the fixing aid to 90 parts by mass of the polyester resin and heating at 150 ° C. is Tgr ′. In this case, ΔTg = Tgr−Tgr ′> 10 ° C. is preferably satisfied, and ΔTg = Tgr−Tgr ′> 15 ° C. is more preferable.

  Here, the glass transition temperature (Tgr) of the polyester resin and the glass transition temperature (Tgr ′) of the polyester resin when 10 parts by mass of the fixing auxiliary component are added are, for example, a DSC system (differential scanning calorimeter) (“DSC− 60 ", manufactured by Shimadzu Corporation).

  First, about 5.0 mg of a polyester resin was placed in an aluminum sample container, and the sample container was placed on a holder unit and set in an electric furnace. Subsequently, it heated from 20 degreeC to 150 degreeC with the temperature increase rate of 10 degree-C / min in nitrogen atmosphere. Thereafter, the sample is cooled from 150 ° C. to 0 ° C. at a temperature decrease rate of 10 ° C./min, and further heated to 150 ° C. at a temperature increase rate of 10 ° C./min, and a differential scanning calorimeter (“DSC-60”, manufactured by Shimadzu Corporation) Thus, the DSC curve was measured. From the obtained DSC curve, using the analysis program in the DSC-60 system, the shoulder of the DSC curve at the second temperature rise can be selected, and the glass transition temperature (Tgr) of the polyester resin can be calculated.

  Further, the glass transition temperature (Tgr ') of the polyester resin when 10 parts by mass of the auxiliary fixing component is added can be measured in the same manner.

  First, 0.5 mg of a fixing auxiliary component and 4.5 mg of a polyester resin were placed in an aluminum sample container, and the sample container was placed on a holder unit and set in an electric furnace. Subsequently, it heated from 20 degreeC to 150 degreeC with the temperature increase rate of 10 degree-C / min in nitrogen atmosphere. Then, it cooled to 0 degreeC from 150 degreeC with the temperature-fall rate of 10 degree-C / min, and also heated to 150 degreeC with the temperature increase rate of 10 degree-C / min, and measured the DSC curve with the differential scanning calorimeter. From the obtained DSC curve, using the analysis program in the DSC-60 system, the shoulder of the DSC curve at the second temperature increase was selected, and the glass transition temperature (Tgr) of the polyester resin when the fixing auxiliary component was added. ') Can be calculated.

  In the present invention, the binder resin contains a polyester resin because good low-temperature fixability can be obtained. The molecular weight, constituent monomers, and the like of the polyester resin can be appropriately selected according to the purpose. The binder resin may further contain a resin other than the polyester resin. Examples of resins other than polyester resins include homopolymers or copolymers such as styrene monomers, acrylic monomers, and methacrylic monomers, polyol resins, phenol resins, silicone resins, polyurethane resins, and polyamides. Resins, furan resins, epoxy resins, xylene resins, terpene resins, coumarone indene resins, polycarbonate resins, petroleum resins and the like may be mentioned, and two or more may be used in combination.

  The polyester resin is obtained by dehydration condensation of a polyhydric alcohol and a polycarboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol A And divalent alcohols obtained by adding cyclic ethers such as ethylene oxide and propylene oxide to the above. In order to crosslink the polyester resin, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. It is preferable to use a trivalent or higher alcohol together.

  Examples of the polyvalent carboxylic acid include benzene dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid or anhydrides thereof, alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid or anhydrides thereof, and maleic acid. Unsaturated dibasic acids such as acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid and mesaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Basic acid anhydride, trimet acid, pyrometic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxylic acid -2-methyl-2-methylenecarboxypropane, tetrakis (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, anhydrides thereof, partial lower alkyl esters and the like. .

  In the present invention, the polyester resin preferably has an acid value of 5 to 40 mgKOH / g, and more preferably 10 to 30 mgKOH / g. When the acid value is less than 5 mgKOH / g, the affinity with paper, which is the main recording medium, is lowered, so that the low-temperature fixability may be lowered, and negative chargeability is difficult to obtain, and the formed image May deteriorate. Further, when the acid value is less than 5 mgKOH / g, the compatibility with the dibasic acid ester compound, which is a fixing auxiliary component in the present invention, may be inferior, so that sufficient low-temperature fixability may not be obtained. . On the other hand, when the acid value exceeds 40 mgKOH / g, the image may be deteriorated by being easily influenced by the environment in an environment such as high temperature and high humidity or low temperature and low humidity.

  In the present invention, the polyester resin preferably has a hydroxyl value of 5 to 100 mgKOH / g, more preferably 20 to 60 mgKOH / g. When the hydroxyl value is less than 5 mgKOH / g, the affinity with paper, which is the main recording medium, is lowered, so that the low-temperature fixability may be lowered, and the negative chargeability is hardly obtained and formed. The image may be deteriorated. In addition, when the hydroxyl value is less than 5 mgKOH / g, the compatibility with the fatty acid amide compound which is a fixing auxiliary component in the present invention may be inferior, and thus sufficient low-temperature fixability may not be obtained. . On the other hand, when the hydroxyl value exceeds 100 mgKOH / g, the image may be deteriorated under the environment of high temperature and high humidity, low temperature and low humidity, and the like.

  The polyester resin preferably has at least one peak in the molecular weight range of 3000 to 50000 in the molecular weight distribution of the component soluble in THF from the viewpoint of toner fixing property and offset resistance. More preferably, it has at least one peak in the 20000 region. Furthermore, the component of the polyester resin soluble in THF preferably has a content of a component having a molecular weight of 100000 or less of 60 to 100% by weight. The molecular weight distribution of the polyester resin is measured by gel permeation chromatography (GPC) using THF as a solvent.

  The binder resin preferably has a glass transition temperature (Tg) of 55 to 80 ° C., more preferably 60 to 75 ° C., from the viewpoint of toner storage stability. When the Tg is in the above range, the stability at high temperature storage is excellent, and the effect of softening the binder resin by the fixing auxiliary component of the present invention is sufficiently large.

  There is no restriction | limiting in particular as said mold release agent, Although it can select suitably according to the objective, The low melting-point mold release agent whose melting | fusing point is 60-90 degreeC is preferable. The low melting point release agent, when dispersed with the resin, effectively acts as a release agent between the fixing roller and the toner interface, thereby preventing oilless (a release agent such as oil on the fixing roller). Even if it is not applied), the hot offset property is good. In particular, in the present invention, it is assumed that the fixing roller temperature is used at a preset temperature lower than that of the conventional one by fixing the toner at a low temperature by introducing a fixing auxiliary component, so that it is necessary to exhibit releasability at a lower temperature. Therefore, a release agent having a melting point of 90 ° C. or higher is preferably used. In addition, when the melting point of the release agent is less than 60 ° C., the high-temperature storage stability of the toner may be inferior, and the obtained image may be deteriorated.

  Examples of the waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cercin; paraffin and micro wax And natural waxes such as petroleum waxes such as crystallin and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax, and polypropylene; synthetic waxes such as esters, ketones, and ethers; Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, and chlorinated hydrocarbons; low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n -Polyacrylate homopolymer or copolymer such as lauryl methacrylate (eg, n-stearyl acrylate-ethyl methacrylate copolymer); crystalline polymer having a long alkyl group in the side chain, etc. Good.

These may be used alone or in combination of two or more.
Among the release agents, as the release agent of the present invention, hydrocarbon waxes such as paraffin, polyethylene, microcrystalline, and polypropylene are preferable. Since the hydrocarbon wax has low compatibility with the fatty acid amide compound which is a fixing auxiliary component of the present invention, it can act independently without impairing the functions of each other, so that sufficient low temperature fixability can be obtained. Can be obtained.

  The colorant can be appropriately selected from known dyes and pigments according to the purpose. 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, Isoindolinone Yellow, Bengala, Lead Red, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para red Parachloroorthonitroaniline red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, 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, Pigment Scarlet 3B, Bordeaux 5B, Tolujing 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 , Pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue rake, peacock blue rake, Victoria blue rake, metal free phthalocyanine blue, phthalocyanine blue, fast sky blue , Indanthrene Blue (RS, BC), Indigo, Ultramarine, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian , Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Examples include green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, ritbon, and the like.

  The content of the colorant in the toner material is preferably 1 to 15% by weight, and more preferably 3 to 10% by weight. If the content is less than 1% by weight, the coloring power of the toner may be reduced. If the content exceeds 15% by weight, poor dispersion of the pigment in the toner will occur. The characteristics may be degraded.

  The colorant may be used as a master batch combined with a resin. Examples of such resins include polyesters, styrene or substituted polymers thereof, styrene copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, and epoxy resins. , Epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax 2 or more types may be used in combination.

  Examples of the polymer of styrene or a substituted product thereof include polystyrene, poly (p-chlorostyrene), and polyvinyl toluene. Examples of the styrene copolymer include styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer. Copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic copolymer Acid butyl copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene- Acrylonitrile-indene copolymer, steel Down - maleic acid copolymer, styrene - maleic acid ester copolymers and the like.

  The master batch can be manufactured by applying a high shear force and mixing or kneading the resin and the colorant. At this time, it is preferable to add an organic solvent in order to enhance the interaction between the colorant and the resin. Also, the so-called flushing method is preferable in that the wet cake of the colorant can be used as it is, and there is no need to dry it. The flushing method is a method in which an aqueous paste containing water of a colorant is mixed or kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove water and the organic solvent. For mixing or kneading, for example, a high shear dispersion device such as a three-roll mill can be used.

  The toner of the present invention can further contain a charge control agent, inorganic fine particles, a cleaning improver, a magnetic material, and the like.

  Examples of the charge control agent include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts). ), Alkylamide, simple substance or compound of phosphorus, simple substance or compound of tungsten, fluorine-based surfactant, metal salt of salicylic acid, metal salt of salicylic acid derivative, and the like.

  Commercially available products may be used as the charge control agent. For example, bontron 03 of nigrosine dye, bontron P-51 of quaternary ammonium salt, bontron S-34 of metal-containing azo dye, oxynaphthoic acid metal complex E-82, E-84 of salicylic acid metal complex, E-89 of phenol-based condensate (above, manufactured by Orient Chemical Co., Ltd.), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, Hodogaya) Chemical Industry Co., Ltd.) Quaternary ammonium salt copy charge PSY VP2038, Triphenylmethane derivative copy blue PR, Quaternary ammonium salt copy charge NEG VP2036, Copy charge NX VP434 (above, Hoechst), LRA-901 LR-147 which is a boron complex (manufactured by Nippon Carlit), copper lid Examples thereof include polymer compounds having functional groups such as Russianine, perylene, quinacridone, azo pigments, sulfonic acid groups, carboxyl groups, and quaternary ammonium bases.

  The content of the charge control agent in the toner composition is, for example, preferably 0.1 to 10% by weight, and more preferably 0.2 to 5% by weight with respect to the binder resin. If the content is less than 0.1% by weight, the charge controllability may not be obtained. If the content exceeds 10% by weight, the chargeability of the toner becomes too large and the effect of the main charge control agent is reduced. As a result, the electrostatic attraction force with the developing roller increases, which may lead to a decrease in toner fluidity and a decrease in image density.

The inorganic fine particles are used as an external additive for imparting fluidity, developability, chargeability and the like to the toner. Examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth, Examples thereof include chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
The inorganic fine particles preferably have a primary particle size of 5 nm to 2 μm, more preferably 5 to 500 nm.

The content of the inorganic fine particles in the toner is preferably 0.01 to 5.0% by weight, and more preferably 0.01 to 2.0% by weight.
The inorganic fine particles are preferably surface-treated with a fluidity improver. As a result, the hydrophobicity of the inorganic fine particles is improved, and a decrease in fluidity and chargeability can be suppressed even under high humidity. Examples of the fluidity improver include, for example, 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, and modified silicone oil. Is mentioned. Silica and titanium oxide are preferably surface-treated with a fluidity improver and used as hydrophobic silica and hydrophobic titanium oxide.

  The cleaning property improver is used to facilitate removal of toner remaining on the photoreceptor and the primary transfer medium after transfer. Examples of the cleaning improver include fatty acid metal salts such as zinc stearate and calcium stearate, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and preferably have a volume average particle size of 0.01 to 1 μm.

  Examples of the magnetic material include iron powder, magnetite, and ferrite. The magnetic material is preferably white from the viewpoint of the color tone of the toner.

  The toner of the present invention is excellent in low-temperature fixability and offset resistance, and can form a high-quality image over a long period of time. Therefore, the toner of the present invention can be used in various fields, and is particularly preferably used for image formation by electrophotography.

-Toner production method-
The method for producing the toner is not particularly limited and can be appropriately selected according to the purpose from conventionally known toner production methods. For example, a kneading / pulverizing method, a polymerization method, a dissolution suspension method, The spray granulation method etc. are mentioned. Among these, the dissolution suspension method and the polymerization method generated in an aqueous medium are particularly preferable because the fixing auxiliary component and the polyester resin are easily formed in an incompatible state during toner production.

-Kneading and grinding method-
In the kneading and pulverizing method, for example, a toner material containing at least a binder resin, a release agent, and a fixing auxiliary component is melt-kneaded, and the obtained kneaded material is pulverized and classified, whereby the base material of the toner is obtained. A method for producing particles.

  In the melt kneading, the toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, a KTK type twin screw extruder manufactured by Kobe Steel, a TEM type extruder manufactured by Toshiba Machine Co., Ltd., a twin screw extruder manufactured by Casey Kay Co., Ltd., a PCM type twin screw extruder manufactured by Ikegai Co., Ltd. Used. This melt-kneading is preferably performed under appropriate conditions that do not cause the molecular chains of the binder resin to be broken. Specifically, the melt kneading temperature is determined with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

  In the pulverization, the kneaded product obtained by the kneading is pulverized. In this pulverization, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.

In the classification, the pulverized product obtained by the pulverization is classified and adjusted to particles having a predetermined particle diameter. The classification can be performed, for example, by removing the fine particle portion with a cyclone, a decanter, a centrifuge, or the like.
After the pulverization and classification are completed, the pulverized product is classified into an air stream by centrifugal force or the like, and toner base particles having a predetermined particle diameter can be produced.

  Next, the external additive is externally added to the toner base particles. By mixing and stirring the toner base particles and the external additive using a mixer, the surface of the toner base particles is coated while being crushed. At this time, it is important from the viewpoint of durability that the external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the toner base particles.

-Polymerization method-
As a method for producing a toner by the polymerization method, for example, a toner material containing a modified polyester resin capable of at least urea or urethane bond, a release agent, and a fixing aid is dissolved or dispersed in an organic solvent. Then, the solution or dispersion is dispersed in an aqueous medium, subjected to a polyaddition reaction, the solvent of this dispersion is removed and washed.

  Examples of the modified polyester resin capable of being bonded with urea or urethane include, for example, polyester prepolymer having an isocyanate group obtained by reacting a carboxyl group or a hydroxyl group at a terminal of a polyester with a polyvalent isocyanate compound (PIC). Can be mentioned. The modified polyester resin obtained by crosslinking and / or extending the molecular chain by the reaction of this polyester prepolymer and amines can improve the hot offset property while maintaining the low temperature fixability.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane). Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; And those blocked with oxime, caprolactam, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The ratio of the polyvalent isocyanate compound (PIC) is preferably 5/1 to 1/1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group, 4/1 to 1.2 / 1 is more preferable, and 2.5 / 1 to 1.5 / 1 is more preferable.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having the isocyanate group is preferably 1 or more, more preferably 1.5 to 3 on average, and 1.8 to 2.5 on average. Is more preferable.

  Examples of amines (B) to be reacted with the polyester prepolymer include a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4), an amino acid (B5). ), B1 to B5 amino groups blocked (B6), and the like.

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-). Dimethyl dicyclohexyl methane, diamine cyclohexane, isophorone diamine, etc.); aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine.

  Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline.

  Examples of the amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.

  Examples of the blocked B1-B5 amino group (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). . Among these amines (B), B1 and a mixture of B1 and a small amount of B2 are particularly preferable.

  The ratio of the amines (B) is equivalent to the equivalent ratio [NCO] / [NHx of the isocyanate group [NCO] in the polyester prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (B). ] Is preferably 1/2 to 2/1, more preferably 1.5 / 1 to 1 / 1.5, and still more preferably 1.2 / 1 to 1 / 1.2.

  According to the method for producing a toner by the polymerization method as described above, a toner having a small particle diameter and a spherical shape can be produced at low cost with little environmental load.

  The developer of the present invention has the toner of the present invention, but may further have a component such as a carrier, and may be used as a one-component developer composed of toner, a two-component developer composed of toner and carrier, or the like. However, it is preferable to use a two-component developer in the high-speed printer and the like corresponding to the recent improvement in information processing speed from the viewpoint of improving the service life. Such a developer can be used in various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

  When the developer of the present invention is used as a one-component developer, there is little fluctuation in the particle size of the toner even if the balance of the toner is performed, and the blade for filming the toner on the developing roller and thinning the toner The toner can be prevented from being fused to a member such as the above, and good and stable developability can be obtained even in the long-term use (stirring) of the developing device.

  In addition, when the developer of the present invention is used as a two-component developer, even if the toner balance over a long period of time is performed, there is little fluctuation in the particle size of the toner, and good and stable even with long-term stirring in the developing device. Developability is obtained.

  The content of the carrier in the two-component developer is preferably 90 to 98% by weight, and more preferably 93 to 97% by weight.

  The carrier is not particularly limited, but preferably has a core material and a resin layer covering the core material.

  Examples of the core material include 50 to 90 emu / g manganese-strontium (Mn—Sr) -based material, manganese-magnesium (Mn—Mg) -based material, and two or more of them may be used in combination. In terms of securing image density, it is preferable to use a highly magnetized material such as iron powder (100 emu / g or more) or magnetite (75 to 120 emu / g) as the core material. In addition, a copper-zinc (Cu-Zn) system (30 to 80 emu / g) is used as a core material in that it can weaken the hitting of the photoconductor in which the toner is in a spiked state, and is advantageous in improving the image quality. It is preferable to use a weakly magnetized material such as

  The core material preferably has a volume average particle size (D50) of 10 to 150 μm, more preferably 20 to 80 μm. If D50 is less than 10 μm, fine particles increase in the particle size distribution of the carrier, so that the magnetization per particle may decrease and carrier scattering may occur. On the other hand, if D50 exceeds 150 μm, the specific surface area of the carrier may decrease and toner scattering may occur. As a result, the reproducibility of the solid portion may be deteriorated particularly in a full color with many solid portions.

  Examples of the material of the resin layer include amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, polyester resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoro Ethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, terpolymer of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomer Examples thereof include fluoroterpolymers such as polymers, silicone resins, and the like, and two or more of them may be used in combination.

  Examples of the amino resin include urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Examples of the polyvinyl resin include acrylic resin, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, and polyvinyl butyral. Examples of polystyrene resins include polystyrene and styrene-acrylic copolymers. Examples of the halogenated olefin resin include polyvinyl chloride. Examples of the polyester-based resin include polyethylene terephthalate and polybutylene terephthalate.

  Moreover, a resin layer may contain conductive powder etc. as needed. Examples of the conductive powder material include metals, carbon black, titanium oxide, tin oxide, and zinc oxide. The conductive powder preferably has an average particle size of 1 μm or less. When the average particle size exceeds 1 μm, it may be difficult to control the electric resistance.

  The resin layer is formed by, for example, preparing a coating solution by dissolving a silicone resin or the like in a solvent, and then applying the coating solution to the surface of the core material by a known coating method, followed by drying and baking. Can do. Examples of the application method include a dipping method, a spray method, and a brush coating method. Examples of the solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, celsol butyl acetate and the like. Furthermore, the baking method may be either an external heating method or an internal heating method, for example, a method using a fixed electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, or the like, or using a microwave. Methods and the like.

  The content of the resin layer in the carrier is preferably 0.01 to 5.0% by weight. If the content is less than 0.01% by weight, a uniform resin layer may not be formed on the surface of the core material. If the content exceeds 5.0% by weight, the resin layer becomes too thick and the carriers are formed. Particles may be generated and a uniform carrier may not be obtained.

  The developer of the present invention can be suitably used for image formation by various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

The developer container of the present invention contains the developer of the present invention, but the container is not particularly limited and can be appropriately selected from known ones, but has a container body and a cap. Etc.
In addition, the size, shape, structure, material, etc. of the container body are not particularly limited, but the shape is preferably cylindrical, etc., spiral irregularities are formed on the inner peripheral surface, and by rotating, It is particularly preferable that the developer as the contents can move to the discharge port side, and that some or all of the spiral irregularities have a bellows function. Furthermore, the material is not particularly limited, but is preferably one having good dimensional accuracy. For example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, Examples thereof include resin materials such as polyacetal resin.

  Since the developer container is easy to store and transport and has excellent handleability, the developer container can be detachably attached to a process cartridge, an image forming apparatus, etc., which will be described later, and used for replenishing the developer.

The image forming method of the present invention preferably has at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, more preferably a cleaning step. You may have a process, a recycling process, a control process, etc.
The image forming apparatus of the present invention preferably includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit, and further includes a cleaning unit. Preferably, it may have, for example, a static elimination means, a recycling means, a control means, etc. as necessary.

  The image forming method of the present invention can be carried out using the image forming apparatus of the present invention, the electrostatic latent image forming step using an electrostatic latent image forming unit, and the developing step using a developing unit. The transfer step can be performed using a transfer unit, the fixing step can be performed using a fixing unit, and the other steps can be performed using other units.

  The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image carrier such as a photoconductive insulator or a photoconductor. The material, shape, structure, size and the like of the electrostatic latent image carrier are not particularly limited and can be appropriately selected from known ones, but the shape is preferably a drum shape. Examples of the photoreceptor include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Among these, an amorphous silicon photoconductor is preferable because of its long life.

The electrostatic latent image is formed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it like an image, and can be formed using electrostatic latent image forming means. The electrostatic latent image forming means includes, for example, a charger that applies a voltage to the surface of the electrostatic latent image carrier and uniformly charges it, and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise. Have at least.
The charger is not particularly limited. For example, a known contact charger including a conductive or semiconductive roll, brush, film, rubber blade, etc., non-contact charging using corona discharge such as corotron and scorotron. A vessel or the like can be used.

  The exposure device is not particularly limited as long as it can be exposed like an image to be formed on the surface of the electrostatic latent image carrier charged by the charger. For example, a copying optical system, a rod lens array system, a laser optical Various exposure devices such as an optical system and a liquid crystal shutter optical system can be used. In addition, you may employ | adopt the light back system which performs imagewise exposure from the back surface side of an electrostatic latent image carrier.

  The developing step is a step of developing the electrostatic latent image with the developer of the present invention to form a toner image, and the visible image can be formed using a developing unit. The developing means is not particularly limited as long as it can be developed with the developer of the present invention. For example, a developing device that contains the developer of the present invention and can apply toner to the electrostatic latent image in a contact or non-contact manner. A developing device equipped with the developer container of the present invention is preferable. The developing device may be either a dry developing method or a wet developing method, and may be either a single color developing device or a multicolor developing device. For example, the developer of the present invention may be obtained by friction stirring. Examples include a stirrer to be charged and a rotatable magnet roller. In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. The magnet roller is disposed in the vicinity of the electrostatic latent image carrier, and a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted by the electrostatic latent image carrier. Move to the surface. As a result, the electrostatic latent image is developed with toner, and a toner image is formed on the surface of the electrostatic latent image carrier. The developer housed in the developing device is the developer of the present invention, but may be a one-component developer or a two-component developer.

  The transfer step is a step of transferring the toner image to a recording medium by charging the electrostatic latent image carrier on which the toner image is formed using, for example, a transfer charger, and transferring the image using a transfer unit. be able to. At this time, the transfer step preferably includes a primary transfer step of transferring the toner image onto the intermediate transfer member and a secondary transfer step of transferring the toner image transferred onto the intermediate transfer member onto the recording medium. The transfer process includes a primary transfer process in which a toner image of two or more colors, preferably a full color toner, is used to transfer a toner image of each color onto an intermediate transfer member to form a composite toner image, and on the intermediate transfer member. It is more preferable to have a secondary transfer step of transferring the formed composite toner image onto a recording medium.

  The transfer unit includes a primary transfer unit that transfers a toner image onto an intermediate transfer member to form a composite toner image, and a secondary transfer unit that transfers the composite toner image formed on the intermediate transfer member onto a recording medium. It is preferable. The intermediate transfer member is not particularly limited, and examples thereof include an endless transfer belt. The transfer means (primary transfer means and secondary transfer means) preferably has at least a transfer device that charges and separates the toner image formed on the electrostatic latent image carrier on the recording medium side. The transfer means can have one or more transfer devices.

Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited, and can be appropriately selected from known recording media (recording paper).

  The fixing step is a step of fixing the toner image transferred to the recording medium, and can be fixed using a fixing unit. When two or more color toners are used, the toner may be fixed each time the toner of each color is transferred to the recording medium, or the toner of all colors may be transferred to the recording medium and fixed in a stacked state. Also good. The fixing unit is not particularly limited, and a known heating and pressing unit can be used. Examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt. At this time, heating temperature is 80-200 degreeC normally. If necessary, for example, a known optical fixing device may be used together with the fixing unit or instead of the fixing unit.

  The neutralization step is a step of neutralizing by applying a neutralization bias to the electrostatic latent image carrier, and the neutralization can be performed using a neutralization unit. The neutralization means is not particularly limited as long as a neutralization bias can be applied to the electrostatic latent image carrier. For example, a neutralization lamp can be used.

  The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier and can be cleaned using a cleaning unit. The cleaning means is not particularly limited as long as the toner remaining on the electrostatic latent image carrier can be removed. For example, a magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, brush cleaner, web A cleaner or the like can be used.

  The recycling step is a step of recycling the toner removed in the cleaning step to the developing unit, and can be recycled using the recycling unit. The recycling unit is not particularly limited, and a known transport unit or the like can be used.

  A control process is a process of controlling each process, and can be controlled using a control means. The control means is not particularly limited as long as the operation of each means can be controlled. For example, a sequencer, a computer, or the like can be used.

  FIG. 1 shows an example of an image forming apparatus of the present invention. The image forming apparatus (100A) includes a photosensitive drum (10) as an electrostatic latent image carrier, a charging roller (20) as a charging unit, an exposure device (not shown) as an exposure unit, and a developing unit. A developing device (40), an intermediate transfer member (50), a cleaning device (60) having a cleaning blade as a cleaning means, and a static elimination lamp (70) as a static elimination means.

The intermediate transfer member (50) is an endless belt, is stretched by three rollers 51 arranged on the inner side thereof, and can move in the direction of the arrow. A part of the three rollers (51) also functions as a transfer bias roller capable of applying a predetermined transfer bias (primary transfer bias) to the intermediate transfer member (50).
Further, a cleaning device (90) having a cleaning blade is disposed in the vicinity of the intermediate transfer member (50). Further, a transfer roller (80) as a transfer means capable of applying a transfer bias for transferring (secondary transfer) the toner image onto the recording paper (95) is disposed to face the intermediate transfer member (50). Has been.
Further, around the intermediate transfer member (50), a corona charger (52) for applying a charge to the toner image on the intermediate transfer member (50) includes a photosensitive drum (10) and the intermediate transfer member (50). ) And the contact portion between the intermediate transfer member 50 and the recording paper (95).
A developing device (40) for each color of black (K), yellow (Y), magenta (M), and cyan (C) includes a developer container (41), a developer supply roller (42), a developing roller ( 43).

  In the image forming apparatus (100A), the photosensitive drum (10) is uniformly charged by the charging roller (20), and then the exposure light L is imaged onto the photosensitive drum (10) by an exposure apparatus (not shown). Exposure is performed to form an electrostatic latent image. Next, the electrostatic latent image formed on the photosensitive drum (10) was developed by supplying a developer from the developing device (40) to form a toner image, and then applied from the roller (51). The toner image is transferred (primary transfer) onto the intermediate transfer member (50) by the transfer bias. Further, the toner image on the intermediate transfer member (50) is given a charge by the corona charger (52) and then transferred (secondary transfer) onto the recording paper (95). The toner remaining on the photosensitive drum 10 is removed by the cleaning device (60), and the photosensitive drum (10) is once discharged by the discharging lamp (70).

FIG. 2 shows another example of the image forming apparatus of the present invention. The image forming apparatus (100B) is a tandem color image forming apparatus, and includes a copying apparatus main body (150), a paper feed table (200), a scanner (300), and an automatic document feeder (ADF) (400). Have.
The copying machine main body (150) is provided with an endless belt-like intermediate transfer member (50) at the center. The intermediate transfer member (50) is stretched around the support rollers (14), (15) and (16), and can rotate in the direction of the arrow.

A cleaning device (17) for removing toner remaining on the intermediate transfer member (50) is disposed in the vicinity of the support roller (15). The intermediate transfer member (50) stretched by the support roller (14) and the support roller (15) is provided with four image forming units (18, yellow, cyan, magenta, and black) along the transport direction. ) Are arranged in parallel with each other, and a tandem developing device (120) is arranged. As shown in FIG. 3, the image forming means (18) for each color includes a photosensitive drum (10), a charging roller (20) for uniformly charging the photosensitive drum (10), and a photosensitive drum (10). A developing device (40) for developing a toner image by developing the electrostatic latent image formed on the toner with a developer of each color of black (K), yellow (Y), magenta (M), and cyan (C); A transfer roller (80) for transferring the toner image onto the intermediate transfer member (50), a cleaning device (60), and a static elimination lamp (70).
An exposure device (30) is disposed in the vicinity of the tandem developing device (120). The exposure device (30) exposes the exposure light L on the photosensitive drum (10) to form an electrostatic latent image.

  Further, a secondary transfer device (22) is arranged on the opposite side of the intermediate transfer member (50) from the side where the tandem developing device (12) is arranged. The secondary transfer device (22) includes a secondary transfer belt (24), which is an endless belt stretched between a pair of rollers (23), and a recording sheet conveyed on the secondary transfer belt (24). The intermediate transfer members (50) can contact each other.

A fixing device (25) is arranged in the vicinity of the secondary transfer device (22). The fixing device (25) includes a fixing belt (26) that is an endless belt, and a pressure roller (27) that is arranged to be pressed against the fixing belt (26).
In addition, a reversing device (28) for reversing the recording paper in order to form images on both sides of the recording paper is disposed in the vicinity of the secondary transfer device (22) and the fixing device (25).

  Next, full color image formation (color copy) in the image forming apparatus (100B) will be described. First, a document is set on the document table (130) of the automatic document feeder (ADF) (400) or the automatic document feeder (400) is opened and the document is placed on the contact glass (32) of the scanner (300). Is set and the automatic document feeder (400) is closed. Next, 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 contact glass ( 32) When an original is set on the scanner (300), the first traveling body (33) and the second traveling body 34 travel immediately. At this time, light from the light source is irradiated by the first traveling body (33), and reflected light from the document surface is reflected by the mirror in the second traveling body (34) and read through the imaging lens (35). Light is received by the sensor (36). Thus, a color original (color image) is read, and image information of each color of black, yellow, magenta, and cyan is obtained.

  Further, after the electrostatic latent image of each color is formed on the photosensitive drum (10) based on the obtained image information of each color by the exposure device (30), the electrostatic latent image of each color is developed for each color. Development is performed with the developer supplied from the container (40), and a toner image of each color is formed. The formed toner images of the respective colors are sequentially transferred (primary transfer) on the intermediate transfer body (50) that is rotated and moved by the support rollers (14), (15), and (16). ) To form a composite toner image.

In the paper feed table (200), one of the paper feed rollers (142) is selectively rotated to feed the recording paper from one of the paper feed cassettes (144) provided in multiple stages in the paper bank (143) for separation. Each sheet is separated by a roller (145), sent to a paper feed path (146), transported by a transport roller (147), guided to a paper feed path (148) in the copier body (150), and a registration roller (49 ) And stop. Alternatively, the recording paper on the manual feed tray (54) is fed out, separated one by one by the separation roller (58), put into the manual feed path (53), and abutted against the registration roller (49) and stopped. The registration roller (49) is generally used while being grounded, but may be used in a state where a bias is applied in order to remove paper dust from the recording paper.
Then, the registration roller (49) is rotated in time with the composite toner image formed on the intermediate transfer member (50), and the recording paper is placed between the intermediate transfer member (50) and the secondary transfer device (22). The composite toner image is transferred (secondary transfer) onto the recording paper.

  The recording paper on which the composite toner image has been transferred is conveyed by the secondary transfer device (22) and sent out to the fixing device (25). In the fixing device (25), the composite toner image is fixed on the recording paper by being heated and pressed by the fixing belt (26) and the pressure roller (27). Thereafter, the recording paper is switched by the switching claw (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55), reversed by the reversing device (28) and guided again to the transfer position, and after the image is formed on the back surface, it is ejected by the ejection roller (56) and ejected by the ejection tray ( 57) Stacked on top.

  The toner remaining on the intermediate transfer member (50) after the composite toner image is transferred is removed by the cleaning device (17).

  The process cartridge of the present invention is detachably molded in various image forming apparatuses, and includes an electrostatic latent image carrier that carries an electrostatic latent image, and an electrostatic latent image carried on the electrostatic latent image carrier. And at least developing means for forming a toner image by developing with the developer of the present invention. The process cartridge of the present invention may further include other means as necessary.

  The developing means includes at least a developer container that contains the developer of the present invention and a developer carrier that carries and conveys the developer contained in the developer container. The developing means may further include a regulating member or the like for regulating the thickness of the developer carried.

  FIG. 4 shows an example of the process cartridge of the present invention. The process cartridge (110) includes a photosensitive drum (10), a corona charger (52), a developing device (40), a transfer roller (80), and a cleaning device (90).

  Examples of the present invention will be described below, but the present invention is not limited to the examples. As described above, the method for producing the toner of the present invention is not particularly limited. In the examples, the result of producing the toner using the dissolution suspension method, which is one of the underwater granulation methods, will be described. In addition, a part means a weight part.

(Synthesis of polyester resin A)
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 67 parts of a 2-mole adduct of bisphenol A, 84 parts of a 3-mole adduct of bisphenol A, 274 parts of terephthalic acid and 2 parts of dibutyltin oxide are added. And allowed to react at 230 ° C. for 10 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15 mmHg for 6 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2300, a weight average molecular weight (Mw) of 7000, a glass transition temperature (Tg) of 65 ° C., an acid value of 20 mgKOH / g, and a hydroxyl value of 40 mgKOH / g. there were.

(Synthesis of polyester resin B)
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 77 parts of 2-molar addition product of ethylene oxide of bisphenol A, 74 parts of 3-mole addition product of propion oxide of bisphenol A, 289 parts of terephthalic acid and 2 parts of dibutyltin oxide And allowed to react at 230 ° C. for 8 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15 mmHg for 5 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2100, a weight average molecular weight (Mw) of 5600, a glass transition temperature (Tg) of 62 ° C., an acid value of 35 mgKOH / g, and a hydroxyl value of 95 mgKOH / g. there were.

(Synthesis of polyester resin C)
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 82 parts of a 2-mole addition product of ethylene oxide of bisphenol A, 69 parts of a 3-mole addition product of propion oxide of bisphenol A, 294 parts of terephthalic acid and 2 parts of dibutyltin oxide are added. And allowed to react at 230 ° C. for 8 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15 mmHg for 5 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2100, a weight average molecular weight (Mw) of 5600, a glass transition temperature (Tg) of 60 ° C., an acid value of 45 mgKOH / g, and a hydroxyl value of 105 mgKOH / g. there were.

(Synthesis of polyester resin D)
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 60 parts of bisphenol A ethylene oxide 2 mol adduct, 92 parts of bisphenol A propion oxide 3 mol adduct, 265 parts terephthalic acid and 2 parts dibutyltin oxide are added. And allowed to react at 230 ° C. for 8 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15 mmHg for 5 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2100, a weight average molecular weight (Mw) of 5600, a glass transition temperature (Tg) of 68 ° C., an acid value of 5 mgKOH / g, and a hydroxyl value of 5 mgKOH / g. there were.

(Synthesis of polyester resin E)
Into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 55 parts of ethylene oxide 2 mol adduct of bisphenol A, 97 parts of propion oxide 3 mol adduct of bisphenol A, 260 parts of terephthalic acid and 2 parts of dibutyltin oxide are added. And allowed to react at 230 ° C. for 8 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15 mmHg for 5 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2100, a weight average molecular weight (Mw) of 5600, a glass transition temperature (Tg) of 70 ° C., an acid value of 3 mgKOH / g, and a hydroxyl value of 3 mgKOH / g. there were.

(Synthesis of styrene-acrylic resin)
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 300 parts of ethyl acetate, 200 parts of styrene, 100 parts of acrylic monomer and 5 parts of azobisisobutylnitrile were added, and the temperature was 60 ° C. (atmospheric pressure). ) For 8 hours. Next, 200 parts of methanol was added and stirred for 1 hour, and then the supernatant was removed and dried under reduced pressure to synthesize styrene-acrylic resin A. The obtained styrene-acrylic resin A had Mw of 20000 and Tg of 60 ° C.

(Synthesis of dibasic acid ester compounds)
Each divalent carboxylic acid shown in Table 1 and each monohydric alcohol component shown in Table 1 together with a catalyst, fatty acid and alcohol are put in a reaction vessel at a molar ratio shown in Table 1, and esterified at 240 ° C. in a nitrogen stream. Reaction was conducted to synthesize dibasic acid ester compounds having physical properties shown in Table 1.

(Production of master batch)
1000 parts of water, DBP oil absorption 42 ml / 100 g, pH 9.5 carbon black Printex 35 (Degussa) 540 parts and 1200 parts of polyester resin A were mixed using a Henschel mixer (Mitsui Mining). did. Next, the obtained mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then rolled and cooled, and pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to prepare a master batch.

(Preparation of aqueous medium)
Aqueous medium was prepared by mixing and stirring 306 parts of ion-exchanged water, 265 parts of a 10% by weight suspension of tricalcium phosphate, and 0.2 part of sodium dodecylbenzenesulfonate, and dissolving them uniformly.

  In a beaker, 80 parts of polyester resin A and 100 parts of ethyl acetate were put and dissolved by stirring. Next, 5 parts of the dibasic acid ester compound (1) listed in Table 1, 5 parts of paraffin wax (HNP-11 melting point 77 ° C., manufactured by Nippon Seiki Co., Ltd.) and 10 parts of master batch were added as a release agent. Ultraviscomil (manufactured by Imex) was used for 3 passes under the condition that the feeding speed was 1 kg / hour, the peripheral speed of the disk was 6 m / second, and 80% by volume of zirconia beads having a particle diameter of 0.5 mm were filled. A material solution was prepared.

  Add 150 parts of an aqueous medium into a container, add 100 parts of toner material solution while stirring at 12,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and mix for 10 minutes to prepare an emulsified slurry. did.

  In a Kolben equipped with a stirrer and a thermometer, 100 parts of an emulsified slurry was charged, and the solvent was removed at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min to obtain a dispersed slurry.

  After filtering 100 parts of the dispersion slurry under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, followed by mixing at 12000 rpm for 10 minutes using a TK homomixer, followed by filtration. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered three times. To the obtained filter cake, 10 parts by weight of 10% by weight hydrochloric acid was added, mixed at 12000 rpm for 10 minutes using a TK homomixer, and then filtered. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice to obtain a filter cake.

  The obtained filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and sieved with a 75 μm mesh to obtain base particles.

  100 parts of base particles and 1.0 part of hydrophobic silica H2000 (manufactured by Clariant Japan) as an external additive are mixed for 30 seconds at a peripheral speed of 30 m / sec using a Henschel mixer (manufactured by Mitsui Mining). After 5 cycles of a 1 minute rest treatment, the mixture was sieved with a mesh of 35 μm to obtain a toner. The dispersion diameter of tetraglycerin hexabehenate in the toner was 0.2 μm.

Except for using the polyester resin B instead of the polyester resin A, the same as in Example 1 (including the point that the dibasic ester is dispersed so as to have a dispersion diameter of 0.2 μm), the examples 2 toner was obtained.

  A toner of Example 3 was obtained in the same manner as in Example 1 except that the polyester resin C was used instead of the polyester resin A.

  A toner of Example 4 was obtained in the same manner as in Example 1 except that the polyester resin D was used instead of the polyester resin A.

  A toner of Example 5 was obtained in the same manner as in Example 1 except that the polyester resin E was used instead of the polyester resin A.

  A toner of Example 6 was obtained in the same manner as in Example 1, except that the dibasic acid ester compound (2) shown in Table 1 was used instead of the dibasic acid ester compound (1).

  A toner of Example 7 was obtained in the same manner as in Example 1 except that the dibasic acid ester compound (3) shown in Table 1 was used instead of the dibasic acid ester compound (1).

  A toner of Example 8 was obtained in the same manner as in Example 1, except that the ester compound (4) shown in Table 1 was used instead of the dibasic acid ester compound (1).

  A toner of Example 7 was obtained in the same manner as in Example 1, except that the dibasic acid ester compound (5) shown in Table 1 was used instead of the dibasic acid ester compound (1).

  A toner of Example 8 was obtained in the same manner as in Example 1, except that the ester compound (6) shown in Table 1 was used instead of the dibasic acid ester compound (1).

  A toner of Example 9 was prepared in the same manner except that carnauba wax (WA-05, melting point: 86 ° C., manufactured by Toa Kasei Co., Ltd.) was used instead of paraffin wax as a release agent.

(Comparative Example 1)
A toner of Comparative Example 1 was obtained in the same manner as in Example 1 except that the addition amount of the ester compound (1) was 0 part.

(Comparative Example 2)
A toner of Comparative Example 4 was obtained in the same manner as in Example 1, except that the dibasic acid ester compound (7) shown in Table 1 was used instead of the dibasic acid ester compound (1).

(Comparative Example 3)
A toner of Comparative Example 5 was obtained in the same manner as in Example 1 except that the dibasic acid ester compound (8) shown in Table 1 was used instead of the dibasic acid ester compound (1).

(Comparative Example 4)
A toner of Comparative Example 5 was obtained in the same manner as in Example 1 except that styrene acrylic resin A was used instead of polyester resin A.

As described above, toners of Examples 1 to 11 and Comparative Examples 1 to 4 were prepared. Table 2 shows the resin, dibasic acid ester compound, and release agent used for each toner.

(Creation of carrier)
To 100 parts of toluene, 100 parts of silicone resin organostraight silicone, 5 parts of γ- (2-aminoethyl) aminopropyltrimethoxysilane and 10 parts of carbon black are added and dispersed with a homomixer for 20 minutes. Was prepared. Using a fluidized bed type coating apparatus, a resin layer coating solution was applied to the surface of 1000 parts of spherical magnetite having an average particle size of 50 μm to prepare a carrier.

(Development of developer)
Using a ball mill, 5 parts of toner and 95 parts of carrier were mixed to prepare a developer.
(Evaluation method and evaluation results)
The following evaluation was performed using the obtained developer. The evaluation results are shown in Table 3.

<Fixing temperature limit>
As a fixing roller, type 6200 paper (manufactured by Ricoh) is set using a device in which the fixing unit of the copying machine MF-200 (manufactured by Ricoh) using a Teflon (registered trademark) roller is modified, and the temperature of the fixing roller is set. The copy test was conducted with the change in increments of 5 ° C. The minimum fixing roller temperature at which the residual ratio of the image density after rubbing the fixed image with a pad becomes 70% or more was defined as the minimum fixing temperature. The lower limit fixing temperature is preferably low because power consumption can be suppressed. If it is 135 ° C. or lower, it is at a level causing no problem in practical use.

<Hot offset generation temperature>
The silicone oil application mechanism was removed from the fixing unit of the tandem type color electrophotographic apparatus Imagio Neo C350 (manufactured by Ricoh Co., Ltd.) and remodeled to an oilless fixing system, and tuned so that the temperature and linear velocity could be adjusted. Using this tandem color electrophotographic apparatus, adjustment was made so that 0.85 ± 0.3 mg / cm ² of toner was developed. Fixing the obtained image by changing the temperature of the fixing roller in increments of 5 ° C., measuring the fixing temperature at which hot offset occurs (offset generation temperature), and fixing without causing hot offset The maximum value of the roller temperature was defined as the upper limit of fixing temperature. The fixing upper limit temperature is preferably high because the margin for offset resistance increases, and if it is 190 ° C. or higher, there is no problem in practical use.

<Transfer rate>
Using an image forming apparatus MF2800 (manufactured by Ricoh Co., Ltd.), a black solid image of 15 cm × 15 cm having an average image density of 1.38 or more is formed with a Macbeth reflection densitometer, and the formula Transfer rate [%] = (on recording paper) Amount of toner transferred to toner / amount of toner developed on photoconductor) × 100
From this, the transfer rate was determined. A transfer rate of 90% or more was evaluated as ◎, a transfer rate of 80% or more and less than 90% was evaluated as ◯, a transfer rate of 70% or more and less than 80% was determined as Δ, and a transfer rate of less than 70% was determined as ×.

<Transfer unevenness>
A black solid image was formed using an image forming apparatus MF2800 (manufactured by Ricoh), and the presence or absence of transfer unevenness of the obtained image was visually observed to evaluate transfer unevenness. In addition, there is no transfer unevenness and ◎ is a very good level, ○ there is no transfer unevenness and there is no problem in actual use ○, there is a little transfer unevenness, but at a level that can be actually used The determination was made as Δ for a certain case, x for a transfer unevenness and a practically problematic level as ×.

<Cover>
Using a tandem color electrophotographic apparatus imagio Neo 450 (manufactured by Ricoh Co., Ltd.) having a cleaning blade in contact with the photosensitive member and a charging roller, black solid and white solid at intervals of 1 cm in a direction perpendicular to the rotation direction of the developing sleeve. After outputting 10,000 A4 horizontal charts (image pattern A), a blank image was output and the presence or absence of fogging was visually evaluated. In addition, it determined as the thing which does not have fogging as (circle) and the thing with fogging as x.

<Filming>
Using the image forming apparatus MF2800 (manufactured by Ricoh Co., Ltd.), the photoreceptor after forming 10,000 images is visually inspected to evaluate whether toner components, mainly a release agent, are fixed to the photoreceptor. did. It should be noted that the case where the toner component is not firmly fixed to the photoconductor is confirmed as ◯, the toner component is fixed to the photoconductor, but the level which is not a problem in practice is Δ, the toner component onto the photoconductor is The sticking was confirmed, and a practically problematic level was evaluated as x.
Moreover, the following evaluation was performed using the obtained toner. The evaluation results are shown in Table 3.

<Heat resistant storage stability>
A 50 ml glass container is filled with toner, left in a thermostatic bath at 50 ° C. for 24 hours, then cooled to 24 ° C., and the penetration is measured by a penetration test (JIS K2235-1991). Evaluated. In addition, it judged as (circle), what was 15 mm or more and less than 25 mm as (circle), what was 5 mm or more and less than 15 mm (triangle | delta), and what was less than 5 mm x. At this time, the greater the penetration, the better the heat-resistant storage stability. When the penetration is less than 5 mm, there is a high possibility that a problem will occur in use.

  From Table 3, the toners of the examples are obtained by using the polyester resin having excellent low-temperature fixability and the dibasic acid ester compound having the above-mentioned moderate compatibility with the polyester resin as a fixing auxiliary component. It turns out that it is excellent in property. Furthermore, since a dibasic acid ester compound that can exist as an independent crystal domain in the toner is used, the result is excellent transferability, no image fogging and filming, and high quality over a long period of time. An image can be formed.

The toner of Comparative Example 1 corresponds to the toner obtained by removing the fixing auxiliary component from the toner of Example 1, and therefore the low temperature fixing property was inferior.

  Since the toner of Comparative Example 2 has a high melting point of the dibasic acid ester compound and a low hydroxyl value of the ester compound, it is inferior in compatibility with the polyester resin and sharp melt property at low temperature, so that it has sufficient low-temperature fixability. The result was not obtained.

  In the toner of Comparative Example 3, since the melting point of the dibasic acid ester compound was low and the hydroxyl value of the ester compound was high, the transferability and heat resistant storage stability were deteriorated, resulting in image fogging and filming.

  Since the toner of Comparative Example 4 uses a styrene acrylic resin, sufficient low-temperature fixability cannot be obtained compared to the polyester resin, and the compatibility with the auxiliary auxiliary component is inferior to that of the styrene acrylic resin. The result was not obtained.

  From the above, it can be seen that the toners of the examples are compatible with the low-temperature fixing system, have good offset resistance, and hardly contaminate the fixing device and the image. Furthermore, it can be seen that the toner of the example can form a high-quality toner image over a long period of time.

DESCRIPTION OF SYMBOLS 10 Photosensitive drum 18 Image forming means 20 Charging roller 22 Secondary transfer device 24 Secondary transfer belt 25 Fixing device 30 Exposure device 40 Developer 50 Intermediate transfer body 52 Corona charger 60 Cleaning device 70 Static elimination lamp 80 Transfer roller 90 Cleaning device 100A, 100B Image forming apparatus 110 Process cartridge 120 Tandem developer

JP 2004-245854 A JP-A-4-70765 JP 2006-208609 A (closest publication)

Claims (18)

At least, a binder resins, a colorant, a releasing agent, a toner comprising a fixing auxiliary component comprises a polyester resin wherein the binder resin as a main component, the fixing auxiliary component, the divalent carboxylic It is a dibasic acid ester compound obtained by esterifying an acid and a monohydric aliphatic alcohol, wherein the divalent carboxylic acid has 2 to 6 carbon atoms, and the dibasic acid ester compound has a melting point of 60 ° C to 100 ° C. Toner characterized by being less than.   The toner according to claim 1, wherein an acid value of the dibasic acid ester compound is 0.1 mgKOH / g or more and less than 100 mgKOH / g.   The toner according to claim 1, wherein the divalent carboxylic acid is adipic acid.   The toner according to claim 1, wherein the monohydric aliphatic alcohol is a linear saturated aliphatic alcohol.   The toner according to claim 4, wherein the linear saturated aliphatic alcohol has 10 to 24 carbon atoms.   6. The toner according to claim 1, wherein the release agent is a hydrocarbon wax having a melting point of 60 ° C. or higher and lower than 90 ° C.   The toner according to claim 1, wherein at least one acid value of the polyester resin is 5 mg KOH / g or more and less than 40 mg KOH / g.   The toner according to claim 7, wherein at least one acid value of the polyester resin is 10 mgKOH / g or more and less than 30 mgKOH / g.   9. The toner according to claim 7, wherein at least one hydroxyl value of the polyester resin is 5 mgKOH / g or more and less than 100 mgKOH / g.   The toner according to claim 1, wherein at least one hydroxyl value of the polyester resin is 20 mgKOH / g or more and less than 60 mgKOH / g.   11. The toner according to claim 1, wherein Tg of at least one polyester resin contained in the toner is 55 ° C. or higher and lower than 80 ° C. 11.   The glass transition temperature of at least one polyester resin contained in the toner is Tgr, and 10 parts by weight of a fixing aid is added to 90 parts by weight of the polyester resin and heated at 150 ° C. The toner according to claim 1, wherein Tgr ′ satisfies the following formula: Tgr−Tgr ′> 10 ° C.   13. The toner according to claim 1, wherein the content of the fixing auxiliary component in the toner is 3% by weight or more and less than 20% by weight.   The toner according to claim 1, wherein the toner is produced in an aqueous medium.   A developer comprising the toner according to claim 1.   A toner-filled container filled with the toner according to claim 1.   The image forming apparatus main body includes at least an electrostatic latent image carrier and developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a visible image. A process cartridge which is detachable, wherein the toner is the toner according to claim 1.   An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, a developing step of developing the electrostatic latent image with toner to form a visible image, and the visible image 15. The image forming method comprising at least a transfer step of transferring the toner image to a recording medium and a fixing step of fixing the transferred image transferred to the recording medium, wherein the toner is according to any one of claims 1 to 14. An image forming method comprising toner.

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