toner

Abstract

To provide toner which has superior heat-resistant storage stability, low-temperature fixability, and filming properties.SOLUTION: Toner contains at least a crystalline polyester resin and a partially hydrogenated petroleum resin, in which the partially hydrogenated resin has a hydrogenation rate of 30-70%, and a content of the partially hydrogenated petroleum resin with respect to the toner is 1-15 mass%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to toner.

Background Art

[0002] Conventionally, in electrophotographic devices, electrostatic recording devices, etc., an electrostatic latent image or a magnetic latent image is visualized by an electrostatic latent image developing toner (also referred to as "toner" in the present invention). For example, in the electrophotographic method, an electrostatic latent image is formed on a photoreceptor, and then the electrostatic latent image is developed using toner to form a toner image. The toner image is usually transferred onto a recording medium such as paper and then fixed by a method such as heating.

[0003] In recent years, the development of toner considering the impact on the environment has been demanded. Therefore, the requirement for achieving both low-temperature fixing property and heat-resistant storage property of toner has been increasing. This is to achieve energy saving by reducing the energy required for fixing.

[0004] As a method for achieving both low-temperature fixing property and heat-resistant storage property of toner, a toner using a petroleum resin as a resin component has been proposed. Among them, a technique of using a hydrogenated petroleum resin (also referred to as "hydrogenated petroleum resin" in the present invention) and a styrene-based resin in combination is already known. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 9-222751), in an electrostatic charge image developing toner obtained by adding a hydrogenated petroleum resin to a resin containing 5 to 50% by weight of a tetrahydrofuran-insoluble component, an electrostatic charge image developing toner characterized in that the tetrahydrofuran-insoluble component content of the toner is 1 to 20% by weight is disclosed. In a specific embodiment, a toner using a hydrogenated petroleum resin and a styrene-acrylic resin in combination is disclosed.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the toner described in Patent Document 1 above, while exhibiting sufficient heat resistance and low-temperature fixation properties, had the problem of poor dispersibility and consequently poor filming performance.

[0006] Therefore, the object of the present invention is to provide a toner with excellent heat resistance, low-temperature fixability, and filming properties. [Means for solving the problem]

[0007] The above problem is solved by the following configuration 1). 1) A toner containing at least a crystalline polyester resin and a partially hydrogenated petroleum resin, The hydrogenation rate of the aforementioned partially hydrogenated petroleum resin is 30-70%, and The content of the partially hydrogenated petroleum resin in relation to the toner is 1 to 15% by mass. The glass transition temperature of the aforementioned partially hydrogenated petroleum resin is 70-90°C. The weight-average molecular weight of the aforementioned partially hydrogenated petroleum resin is 2000-4000. The toner is characterized by containing Fischer-Tropsch wax. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a toner with excellent heat resistance for storage, low-temperature fixation, and filming properties. [Brief explanation of the drawing]

[0009] [Figure 1] This is an example of a 1H-NMR spectrum used to calculate the hydrogenation rate of hydrogenated petroleum resins. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described further below. The configuration of the present invention is as described in 1) above, but preferred embodiments of the present invention include the following 2) to 5).

[0011] 2) The toner according to 1) above, characterized in that the toner further contains a hydrocarbon wax. This configuration allows for further improvement in filming capabilities.

[0012] 3) The toner according to 1) or 2) above, characterized in that the glass transition temperature of the partially hydrogenated petroleum resin is 70-90°C. This configuration allows for further improvement of low-temperature fixation and heat-resistant storage properties.

[0013] 4) The toner according to any one of 1) to 3) above, characterized in that the weight-average molecular weight of the partially hydrogenated petroleum resin is 2000-4000. This configuration allows for further improvement of low-temperature fixation and heat-resistant storage properties.

[0014] 5) The toner according to any one of 1) to 4) above, characterized in that the hydrogenation rate of the partially hydrogenated petroleum resin is 40-60%. This configuration allows for even greater filming capabilities.

[0015] <Crystalline polyester resin> The crystalline polyester resin is obtained using a polyhydric alcohol and a polyhydric acid or its derivative, such as a polyhydric carboxylic acid, a polyhydric carboxylic acid anhydride, or a polyhydric carboxylic acid ester. In this invention, crystalline polyester resin refers to a resin obtained using a polyhydric alcohol and a polyhydric carboxylic acid such as a polyhydric carboxylic acid, polyhydric carboxylic acid anhydride, or polyhydric carboxylic acid ester, or a derivative thereof, as described above. Modified polyester resins, such as the prepolymer and resins obtained by crosslinking and / or stretching the prepolymer, do not belong to the category of crystalline polyester resin.

[0016] The presence or absence of crystallinity in the crystalline polyester resin used in this invention can be confirmed by a crystallographic X-ray diffractometer (e.g., X'Pert Pro MRD, Philips). The measurement method is described below. First, crush the target sample with a mortar to create sample powder, and uniformly apply the obtained sample powder to a sample holder. Then, set the sample holder in the diffraction apparatus, perform measurement, and obtain a diffraction spectrum. When the full-width at half maximum of the peak with the largest peak intensity among the peaks obtained in the range of 20° < 2θ < 25° of the obtained diffraction peaks is 2.0 or less, it is determined to have crystallinity. The measurement conditions for X-ray diffraction are described below. 〔Measurement conditions〕 Tension kV: 45kV Current: 40mA MPSS Upper Gonio Scanmode: continuos Start angle: 3° End angle : 35° Angle Step:0.02° Lucident beam optics Divergence slit : Div slit 1 / 2 Difflection beam optics Anti scatter slit: As Fixed 1 / 2 Receiving slit : Prog rec slit

[0017] -Polyhydric alcohol- The polyhydric alcohol is not particularly limited and can be appropriately selected according to the purpose. For example, diols and polyhydric alcohols with three or more hydroxyl groups can be mentioned.

[0018] Examples of the diol include saturated aliphatic diols. Examples of the saturated aliphatic diol include linear saturated aliphatic diols and branched saturated aliphatic diols. Among these, linear saturated aliphatic diols are preferred, and linear saturated aliphatic diols having 2 to 12 carbon atoms are more preferred.

[0019] Examples of saturated aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanediol. Among these, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred because they exhibit high crystallinity in the crystalline polyester resin and excellent sharp-melt properties.

[0020] Examples of trivalent or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used individually or in combination of two or more.

[0021] -Polyhydric carboxylic acids- The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples include divalent carboxylic acids and trivalent or higher carboxylic acids.

[0022] Examples of the aforementioned divalent carboxylic acids include saturated aliphatic dicarboxylic acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, superiric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid; and further, their anhydrides and lower (1-3 carbon atoms) alkyl esters.

[0023] Examples of the carboxylic acids with a valency of 3 or higher include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, and their anhydrides and lower (1-3 carbon atoms) alkyl esters.

[0024] Furthermore, the polycarboxylic acid may include, in addition to the saturated aliphatic dicarboxylic acid and aromatic dicarboxylic acid, a dicarboxylic acid having a sulfonic acid group. In addition, the polycarboxylic acid may also include, in addition to the saturated aliphatic dicarboxylic acid and aromatic dicarboxylic acid, a dicarboxylic acid having a double bond. These may be used individually or in combination of two or more.

[0025] The crystalline polyester resin is preferably composed of a linear saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and a linear saturated aliphatic diol having 2 to 12 carbon atoms. In other words, it is preferable that the crystalline polyester resin has constituent units derived from saturated aliphatic dicarboxylic acids having 4 to 12 carbon atoms and constituent units derived from saturated aliphatic diols having 2 to 12 carbon atoms. This is preferable because it exhibits high crystallinity and excellent sharp melt properties, thus providing excellent low-temperature fixability.

[0026] There are no particular restrictions on the melting point of the crystalline polyester resin, and it can be appropriately selected depending on the purpose, but it is preferably between 60°C and 80°C. This melting point range improves the heat resistance and low-temperature fixing properties of the toner.

[0027] There are no particular restrictions on the molecular weight of the crystalline polyester resin, and it can be appropriately selected according to the purpose. However, from the viewpoint that a sharp molecular weight distribution and low molecular weight resins have excellent low-temperature fixation properties, and that a high proportion of low molecular weight components reduces heat resistance, it is preferable that the soluble content of orthodichlorobenzene in the crystalline polyester resin is such that, as measured by GPC, the weight-average molecular weight (Mw) is 3,000 to 30,000, the number-average molecular weight (Mn) is 1,000 to 10,000, and the Mw / Mn ratio is 1.0 to 10. Furthermore, it is preferable that the weight-average molecular weight (Mw) is 5,000 to 15,000, the number-average molecular weight (Mn) is 2,000 to 10,000, and the Mw / Mn ratio is 1.0 to 5.0.

[0028] There are no particular restrictions on the acid value of the crystalline polyester resin, and it can be appropriately selected depending on the purpose. However, from the viewpoint of affinity between paper and resin, a value of 5 mg KOH / g or more is preferred, and 10 mg KOH / g or more is more preferred, in order to achieve the desired low-temperature fixation. On the other hand, to improve high-temperature offset resistance, a value of 45 mg KOH / g or less is preferred.

[0029] There are no particular restrictions on the hydroxyl value of the crystalline polyester resin, and it can be appropriately selected depending on the purpose. However, in order to achieve the desired low-temperature fixability and good electrostatic properties, a value of 0 mg KOH / g to 50 mg KOH / g is preferred, and 5 mg KOH / g to 50 mg KOH / g is more preferred.

[0030] The molecular structure of the crystalline polyester resin can be confirmed by NMR measurements in solution or solid state, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurements, etc. A simpler method is infrared absorption spectroscopy, which can be used to determine the structure at 965±10 cm⁻¹. -1 or 990±10cm -1 One method involves detecting crystalline polyester resins that exhibit absorption based on δCH (out-of-plane bending vibration) of olefins.

[0031] There are no particular restrictions on the content of the crystalline polyester resin, and it can be appropriately selected depending on the purpose, but it is preferably 5.0% to 15.0% by mass, and more preferably 6.5% to 10.0% by mass, relative to the total amount of toner.

[0032] <Partially hydrogenated petroleum resin> Partially hydrogenated petroleum resins are resins obtained by reducing petroleum resins by partially adding hydrogen to the unsaturated bonds remaining in the resin. Petroleum resins are obtained from petroleum-based unsaturated hydrocarbons, which are refined petroleum-based unsaturated hydrocarbons obtained by the production of ethylene, acetylene, propylene, etc., during naphtha cracking. Examples include C5-C6 aliphatic petroleum resins made from C5-C6 aliphatic hydrocarbons, C5-C6 aromatic petroleum resins made from C6-C8 aromatic hydrocarbons, aliphatic-aromatic polymerized petroleum resins made from both aliphatic and aromatic hydrocarbons, petroleum resins mainly made from dicyclopentanediene, and petroleum resins mainly made from higher olefins. Particularly noteworthy are hydrogenated petroleum resins mainly made from C6-C8 aromatic hydrocarbons, and using these improves heat resistance and storage properties.

[0033] For hydrogenating petroleum resins, any general reduction method can be used, but catalytic reduction is particularly common. Specifically, heavy metal catalysts such as nickel, palladium, and platinum are used, at 150-250°C and 30-50 kg / cm³. 2 This reduction method involves directly reacting hydrogen with petroleum oils and fats under high temperature and pressure, adding hydrogen to the unsaturated double bonds of petroleum resins.

[0034] The hydrogenation rate of the partially hydrogenated petroleum resin used in this invention is 30-70%. If the hydrogenation rate falls outside this range, the effects of this invention cannot be achieved. A more preferable hydrogenation rate for the partially hydrogenated petroleum resin is 40-60%. The hydrogenation rate can be measured by the method described in the examples. The hydrogenation rate can be controlled by changing the reaction pressure during the reduction reaction.

[0035] The glass transition temperature of the partially hydrogenated petroleum resin used in this invention is preferably 70-90°C. This configuration further enhances low-temperature fixability and heat resistance. The glass transition temperature can be controlled by changing the reaction pressure during the reduction reaction. The aforementioned glass transition temperature is the glass transition temperature at the second heating step in the endothermic curve measured using a differential scanning calorimeter.

[0036] <<Method for measuring glass transition temperature (Tg)>> The glass transition temperature (Tg) in this invention can be measured, for example, using a DSC system (differential scanning calorimeter) ("Q-200", manufactured by TA Instruments). Specifically, the glass transition temperature of the target sample can be measured by the following procedure. First, approximately 5.0 mg of the target sample is placed in an aluminum sample container, which is then placed on a holder unit and set in an electric furnace. Next, under a nitrogen atmosphere, the sample is heated from -80°C to 150°C at a heating rate of 10°C / min (first heating pass). After that, it is cooled from 150°C to -80°C at a cooling rate of 10°C / min, and then heated again to 150°C at a heating rate of 10°C / min (second heating pass). During both the first and second heating passes, a differential scanning calorimeter ("Q-200", manufactured by TA Instruments Inc.) is used to measure the DSC curve. From the obtained DSC curves, the analysis program in the Q-200 system can be used to select the DSC curve for the first heating cycle and determine the glass transition temperature of the target sample during the first heating cycle. Similarly, the DSC curve for the second heating cycle can be selected to determine the glass transition temperature of the target sample during the second heating cycle.

[0037] The weight-average molecular weight of the partially hydrogenated petroleum resin used in this invention is preferably 2000-4000. This embodiment allows for further improvement of low-temperature fixability and heat resistance. The weight-average molecular weight can be controlled by changing the reaction time during the reduction reaction. The weight-average molecular weight is the polystyrene-based molecular weight measured by gel permeation chromatography (GPC) using o-dichlorobenzene as the developing solvent.

[0038] The partially hydrogenated petroleum resin used in the present invention can be produced, for example, by polymerizing a cyclopentadiene compound and a vinyl aromatic compound, as described above. By controlling the reaction time, polymers with varying molecular weights can be produced. The obtained polymers can then be hydrogenated in the presence of a hydrogenation catalyst to produce partially hydrogenated petroleum resins. Furthermore, by changing the pressure in the presence of a hydrogenation catalyst, hydrogenated petroleum resins with varying Tg and hydrogenation rates can be produced.

[0039] There are no particular restrictions on the content of the partially hydrogenated petroleum resin, and it can be appropriately selected depending on the purpose, but it is preferably 1% to 15% by mass, and more preferably 5% to 15% by mass, relative to the total amount of toner.

[0040] <Other ingredients> In addition to the components described above, the toner of the present invention may contain known resins, waxes, colorants, charge control agents, external additives, fluidity enhancers, cleaning properties enhancers, magnetic materials, and the like. In particular, using wax is preferable from the perspective of further improving filming performance.

[0041] Examples of waxes include plant-based waxes such as carnauba wax, cotton wax, and wood wax; animal-based waxes such as beeswax and lanolin; mineral-based waxes such as ozokerite and cerucine; and petroleum waxes such as paraffin, microcrystalline, and petrolatum.

[0042] In addition to these natural waxes, other examples include Fischer-Tropsch wax, synthetic hydrocarbon waxes such as polyethylene and polypropylene, and synthetic waxes such as esters, ketones, and ethers.

[0043] Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons may be used; homopolymers or copolymers of polyacrylates such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate, which are low molecular weight crystalline polymer resins (for example, copolymers of n-stearyl acrylate and ethyl methacrylate); and crystalline polymers having long alkyl groups in their side chains may also be used.

[0044] Among these, hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax are preferred.

[0045] There are no particular restrictions on the wax content, and it can be appropriately selected depending on the purpose, but it is preferably 5.0% to 10.0% by mass relative to the total toner.

[0046] The method for producing the toner of the present invention is not particularly limited. For example, known kneading and grinding methods or dissolution and suspension methods can be employed.

[0047] There are no particular restrictions on the weight-average particle size of the toner of the present invention, and it can be appropriately selected depending on the purpose, but it is preferably 5.0 μm or more and 6.0 μm or less.

[0048] The toner of the present invention can be used as a developer and may contain other components as appropriate, such as a carrier, if necessary. The developer may be a one-component developer or a two-component developer.

[0049] The toner of the present invention can be applied to known image forming apparatuses and image forming methods. The image forming apparatus comprises at least an electrostatic latent image carrier, electrostatic latent image forming means, and developing means, and may further include other means as needed. The image forming method comprises a charging step, an exposure step, a developing step, a primary transfer step, a secondary transfer step, a fixing step, and a cleaning step, and may further include other steps as needed. [Examples]

[0050] The present invention will be further described below with reference to examples, but the present invention is not limited to the following examples. No. Note that "parts" below refers to parts by mass. Also, the examples... 1、9、 The number 10 indicates a reference example not included in the present invention. 1、9、 Let's set it to 10.

[0051] The partially hydrogenated petroleum resin used in the examples was produced by the following manufacturing method. Partially Hydrogenated Petroleum Resin A: First, the hydrogenation raw material was prepared by polymerization of a cyclopentadiene compound and a vinyl aromatic compound. Specifically, 100 parts by mass of dicyclopentadiene, 100 parts by mass of styrene, and 200 parts by mass of xylene were charged into a 1-liter autoclave, and the polymerization reaction was carried out at 260°C for 6 hours. After that, the solvent and low molecular weight polymer were removed by depressurization and reduced pressure, and 300 parts by mass of ethylcyclohexane was added to the remaining 100 parts by mass of resin and dissolved to obtain the hydrogenation raw material. Next, the above-mentioned hydrogenation material was subjected to hydrogenation treatment using a tubular reactor. Specifically, a tubular reactor filled with a nickel catalyst containing 30% by weight of copper and chromium (carrier: diatomaceous earth, Ni metal loading: 45% by weight) is used to add the hydrogenated raw material obtained above, along with hydrogen in a ratio of 2.5 parts by weight per 100 parts by weight of petroleum resin in the hydrogenated raw material, at a weight space velocity (WHSV) of 0.6 hr. -1 Partially hydrogenated petroleum resin A was obtained by continuously flowing the mixture under conditions of a pressure of 4 MPa·G and a temperature of 200°C. Partially Hydrogenated Petroleum Resin B: Partially hydrogenated petroleum resin B, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin C: Partially hydrogenated petroleum resin C, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin D: Partially hydrogenated petroleum resin D, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin E: Partially hydrogenated petroleum resin E, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially hydrogenated petroleum resin F: Partially hydrogenated petroleum resin F, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin G: Partially hydrogenated petroleum resin G, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin H: Partially hydrogenated petroleum resin H, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin I: Partially hydrogenated petroleum resin I, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin J: Partially hydrogenated petroleum resin J, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A. Partially Hydrogenated Petroleum Resin K: Partially hydrogenated petroleum resin K, as shown in Table 1, was prepared by varying the reaction time with the catalyst, the amount added, the pressure, and the temperature, using the same procedure as for A.

[0052] The hydrogenation rate (%), glass transition temperature (Tg), and weight-average molecular weight (Mw) of each of the partially hydrogenated petroleum resins mentioned above are shown in Table 1 below.

[0053] [Table 1]

[0054] The hydrogenation rate of partially hydrogenated petroleum resin A was calculated using proton NMR. Details are shown below. Approximately 0.1 g of the sample was mixed with 0.7 ml of deuterated chloroform (CDCl3), and after confirming that it had dissolved, it was placed in a φ5 mm NMR tube and used as the sample for NMR measurement. Measuring device: JEOL ECX-500 FT-NMR Measurement temperature: room temperature 1 H-NMR measurement conditions Measurement nucleus = 1H (500MHz), data points = 64K, observation width = 17ppm, number of integrations = 64 Measurement pulse = single pulse.jxp, 45° pulse, Relaxation Delay 5 seconds, offset = 8 ppm As shown in Figure 1, the hydrogenation rate of partially hydrogenated petroleum resin A was calculated as the ratio of the spectral area of ​​the aromatic ring signal before hydrogenation (between 6.5-7.5 ppm) to the spectral area of ​​the aromatic ring signal after hydrogenation (between 1.0-2.0 ppm). The hydrogenation rate of other hydrogenated petroleum resins is calculated in the same manner as above.

[0055] Furthermore, the waxes used in the examples are as follows: Wax A: FT Wax (Fischer-Tropsch Wax FNP-0090, manufactured by Nippon Seiro Co., Ltd.) Wax B: Carnauba wax (manufactured by Toyo Chem Co., Ltd.)

[0056] (Example 1) —Preparation of toner matrix particles— Amorphous polyester resin 69 parts Crystalline polyester resin (melting point 60-80°C, Mw 5500-6500) 8 parts (Method for producing the crystalline polyester resin) Fumaric acid and 1,6-hexanediol were placed in a 5L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple so that the OH / COOH ratio of the fumaric acid and 1,6-hexanediol was 0.9. The mixture was reacted with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours, then the temperature was raised to 200°C and the reaction was continued for 3 hours, followed by a reaction at a pressure of 8.3 kPa for 2 hours to obtain the crystalline polyester used in the examples. 5 parts of the above wax A Carbon black (Mitsubishi Chemical Corporation #44) 11 parts Azo iron compound (T-77 manufactured by Hodogaya Chemical Industry Co., Ltd.) 1 part The above portion of hydrogenated petroleum resin A, 10 parts

[0057] The toner raw materials obtained according to the above formulation were pre-mixed using a Henschel mixer (manufactured by Mitsui Miike Chemical Machinery Co., Ltd., FM20B), and then melted and kneaded at 120°C in a twin-screw kneader (manufactured by Ikegai Co., Ltd., PCM-30). The resulting kneaded material was rolled to a thickness of 2.7 mm using rollers, cooled to room temperature in a belt cooler, and then coarsely ground to 200 μm to 300 μm in a hammer mill. Next, it was finely ground using a supersonic jet pulverizer LabJet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an airflow classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd., MDS-I) while appropriately adjusting the louver opening so that the weight-average particle size was 5.8 ± 0.2 μm, to obtain the toner matrix particles of Example 1.

[0058] —Creation of toner particles— To 100 parts by mass of the above toner matrix particles, hydrophobically treated silica (11 parts by mass) and hydrophobically treated titanium oxide (20.03 parts by mass) were stirred and mixed in a Henschel mixer to prepare an externally treated toner. 5% by mass of the externally treated toner and 95% by mass of the coating ferrite carrier were uniformly mixed at 48 rpm for 5 minutes using a tarbler mixer (manufactured by Willy e Bakkofen (WAB)) to prepare a toner developer. Using an image forming apparatus with the toner developer, the low-temperature fixability, heat resistance, and filming properties were evaluated according to the evaluation method described below.

[0059] <Evaluation of low-temperature fixation> The aforementioned [toner developer] was placed in a Ricoh Co., Ltd. copier (RICOH MPC 6003) and an image was printed. The amount of toner developer applied was 0.4 mg / cm². 2 The solid image was printed onto paper (Ricoh Type 6200) through exposure, development, and transfer processes. The fixing line speed was 256 mm / second. The fixing temperature was sequentially set at 5°C increments, and the lower limit temperature at which cold offset did not occur (lower fixing temperature: low-temperature fixing performance) was measured. The NIP width of the fixing device was 11 mm.

[0060] -Evaluation Criteria for Low-Temperature Fixation- ◎: Below 120℃ ○: 120℃ or higher, but less than 125℃ △: 125℃ or higher and less than 130℃ ×: Above 130℃ A rating of "◎" or "○" indicates a passing grade.

[0061] <Evaluation of heat resistance and storage properties> Toner matrix particles were stored at 50°C for 24 hours, and the penetration depth was measured according to JIS K2235 (25°C). A VR-5610 penetration meter (Shimadzu Corporation) was used to measure the penetration depth. -Evaluation criteria for heat resistance and storage properties- ◎: 4.0mm or larger ○: 1.0 mm or more and less than 4.0 mm △: 0.5mm or more and less than 1.0mm ×: Less than 0.5mm A rating of "◎" or "○" indicates a passing grade.

[0062] <Evaluation of filming capabilities> The aforementioned toner developer was placed in a RICOH MPC 6003 copier manufactured by Ricoh Co., Ltd., and the amount of adhesion was 0.4 mg / cm². 2 The solid image was printed onto paper (Ricoh Type6200, A4 size) through exposure, development, and transfer processes, and a continuous paper-feed test of 2,000 sheets was conducted. Contamination of the latent image carrier and the contamination status were visually observed using a charging device.

[0063] -Filming capability- ○: No contamination on the latent image carrier and no filming on the charging device. △: There is slight contamination on the latent image carrier and some filming on the charging device, which may cause abnormal images to appear over time. ×: Contamination of the latent image carrier and slight filming on the charging device resulted in the early occurrence of abnormal images. A "○" or "△" rating indicates a passing grade.

[0064] The results are shown in Table 2.

[0065] (Examples 2-12 and Comparative Examples 1-4) Example 1 was repeated, except that the type and content of the partially hydrogenated petroleum resin, as well as the type of wax, were changed as shown in Table 2. The results are shown in Table 2.

[0066] [Table 2]

[0067] From the results in Table 2, it was found that the toner of the example, which contains at least a crystalline polyester resin and a partially hydrogenated petroleum resin, wherein the hydrogenation rate of the partially hydrogenated petroleum resin is 30-70%, and the content of the partially hydrogenated petroleum resin relative to the toner is 1-15% by mass, has excellent heat resistance, low-temperature fixability, and filming properties. [Prior art documents] [Patent Documents]

[0068] [Patent Document 1] Japanese Patent Application Publication No. 9-222751

Claims

1. A toner comprising at least a crystalline polyester resin and a partially hydrogenated petroleum resin, The hydrogenation rate of the aforementioned partially hydrogenated petroleum resin is 30 to 70%, and The content of the partially hydrogenated petroleum resin relative to the toner is 1 to 15% by mass. The glass transition temperature of the aforementioned partially hydrogenated petroleum resin is 70-90°C. The weight-average molecular weight of the aforementioned partially hydrogenated petroleum resin is 2000-4000. The toner is characterized by containing Fischer-Tropsch wax.

2. The toner according to claim 1, characterized in that the content of the crystalline polyester resin is 5.0% by mass to 15.0% by mass relative to the total toner.

3. The toner according to claim 1 or 2, characterized in that the hydrogenation rate of the partially hydrogenated petroleum resin is 40-60%.

Images