JP5358972B2 - Image forming method and toner for developing electrostatic image corresponding to gloss level - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which a visualized image is made entirely mat or glossy without uneven glossiness under the request of lower-temperature heat fixing, and to provide an electrostatic charge image developing toner corresponding to glossiness. <P>SOLUTION: The image forming method includes heat-fixing on a recording material a visualized image formed from a toner including a binder resin, a colorant and a wax, wherein the heat fixing temperature is 100-180&deg;C, and the crystal size of the crystalline wax is controlled by imparting heat energy to the visualized image heat-fixed at the temperature, whereby glossiness is changed. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an image forming method such as electrophotography, electrostatic printing, and magnetic recording and a toner for developing an electrostatic charge latent image used in this method, and more specifically, a visible image formed with toner is used. The present invention relates to an image forming method in which glossiness is changed by applying heat energy after heat-fixing on a recording material, and an electrostatic charge image developing toner used in this method.

Recently, technology for obtaining color image prints (also called printing) using electrophotography has been developed, and various copiers, printers, facsimiles and other image forming devices have been marketed. Yes.
In order to obtain a color image print, such an image forming apparatus uses, for example, document image information (including information such as letters, numbers, symbols, pictures, and photographs) by means of document reading means such as blue, green, and red. The color separation filter performs color separation, converts the image data obtained corresponding to each color separation filter into digitized electronic data, and stores it in storage means such as a memory.

  Thereafter, the image bearing member (also referred to as a photosensitive member or a photosensitive drum) is sequentially exposed by the exposure unit based on the image data converted into electronic data, and the electrostatic latent image formed on the photosensitive member by the developing unit. Are developed in order with toners such as yellow (Y), magenta (M), cyan (C), and black (K), which are complementary colors of the color separation filter, to form a toner image. The formed three-color or four-color toner images are transferred and transferred onto a recording material such as a sheet of transfer paper by a transfer separation unit, and fixed by applying a predetermined heat (heat amount) and pressure by a fixing device. A series of operations are performed to be discharged out of the machine.

  Recent color printing by image forming equipment has become possible to form high-quality images with high definition and good reproducibility such as intermediate colors, so that high-quality image quality equivalent to that of photographs and printing is required. Therefore, attention is also paid to the glossiness or glossiness of an image (also simply referred to as gloss), which has not been considered much by conventional image forming apparatuses dedicated to monochrome printing.

  In other words, a full-color image formed on a recording material such as transfer paper with toner greatly changes the sensory atmosphere of the image depending on the presence or absence of gloss on the image surface, and includes, for example, photographs and paintings. In the case of forming a color print, there has been a demand for an image forming apparatus that can arbitrarily select the degree of gloss of an image in consideration of the user's preference and the balance with the gloss of the recording material itself.

In view of this, the present applicant, when the toner contains a wax, when the toner on the recording material such as transfer paper is given a sufficient amount of heat, the wax contained in the toner is melted and the toner is melted. Since the surface of the colorant (also referred to as a colorant) is covered and the surface becomes smoother, if it can be rapidly cooled and kept in this state, a more beautiful glossy image than the image using only the toner can be obtained. Focusing on the results obtained, a technique for changing the gloss by controlling the cooling time after fixing has been developed and proposed previously (see Patent Document 1).
On the other hand, recently, from the viewpoint of energy saving, the thermal energy given to the toner at the time of fixing tends to be small, and it is requested that the glossiness when this toner is heat-fixed at low temperature corresponds to the user's preference. Yes.
In order to respond to such a request, the present inventors examined the above-mentioned prior proposal technique.

The previously proposed technology is as follows.
(1) When the gloss mode is selected, the transfer paper immediately after passing through the fixing device has a high temperature of about 160 ° C., which is close to the fixing temperature, and the transfer paper detection means detects the leading edge of the transfer paper. At the S0 time, all the cooling fans of the air blowing means are started to operate, and the cooling is rapidly performed from about 160 ° C. to 70 ° C. or less during the S1 time. And solidify in a state where the surface is smooth.
(2) When the semi-gloss mode is selected, the state of covering the toner pigment in the process of solidifying the melted wax cannot be maintained completely, resulting in slight unevenness on the surface. Then, after the air blowing means starts operating at S0 time so as to be in a semi-glossy state, control is performed to gradually cool so that it becomes 70 ° C. or less at S2 time.

That is, in the semi-gloss mode, control is performed so as to reduce the number of operating cooling fans of the air blowing means, and control is performed so that the cooling effect is slightly reduced compared to that in the gloss mode.
(3) In the non-glossy mode, the blowing means is operated in S0 time, and is controlled to be gradually cooled to 70 ° C. or less in about S3 time. The wax is solidified in a state where the wax is scattered on the toner pigment so that the surface becomes uneven and is not glossy.
It is a technology.

According to the researches of the present inventors, according to such a previously proposed technique, there is a risk of uneven gloss in the case of low-temperature heat fixing, and in particular, the overall gloss is made non-glossy or glossy while being uniform gloss. Proved difficult.
JP 2006-098461 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming method capable of making the entire gloss of a visible image non-glossy or glossy without a gloss unevenness under a request for low-temperature heat fixing, and for developing an electrostatic image corresponding to the gloss level. To provide toner.

The present invention for solving the above problems has the following configuration.
1. In an image forming method in which a visible image formed with a toner containing a binder resin, a colorant, and a wax is heat-fixed on a recording material,
The heating and fixing temperature is 100 to 180 ° C., and the visible image heat-fixed at this temperature is kept at a temperature equal to or lower than the melting point temperature of the crystalline wax contained in the toner, and is applied to the recording material . heat transfer (the recording material was pinched and conveyed unless transfer heat.), radiation or by the application of thermal energy by convection, by controlling the crystal size of the crystalline wax, images formed Ru changing the glossiness A method ,
The image forming method, wherein the crystalline wax has a melting point of 60 to 90 ° C.

2 . 2. The image forming method as described in 1 above, wherein the heat retention or heating time for applying thermal energy is 10 to 20 minutes.

3 . 3. The image forming method according to 1 or 2 above, wherein the application of thermal energy is performed in a heating chamber provided at a subsequent stage of a fixing device for heating and fixing the visible image on the recording material.

According to the first aspect of the present invention, since the crystal size of the crystalline wax is controlled by applying thermal energy to the heat-fixed visible image, the glossiness of the entire visible image can be reduced without gloss. It can also be glossy.
Further , by adopting a simple thermal energy applying means such as heat retention or heating, the problems of the present invention can be solved, and development of equipment such as a copying machine is easy.

According to the invention described in 1 above, it is possible to control the degree of gloss more stably under low temperature heat fixing by regulating the melting point of the crystalline wax, and development of equipment such as a copying machine is easy. is there.
According to the invention described in the 2, as shown in Table 2 in the Examples below, insulation or heating time, object of the present invention is achieved when the 2.
According to the third aspect of the present invention, as shown in paragraph [0027], it is given as a specific example of the thermal energy applying means.

FIG. 1 is an explanatory diagram showing an example of an image forming apparatus used in an image forming method using toner according to the present invention.
This image forming apparatus is a tandem color image forming apparatus having a configuration in which four sets of image forming units 100Y, 100M, 100C, and 100Bk are provided along an intermediate belt 14a that is an intermediate transfer member.

  Each of the image forming units 100Y, 100M, 100C, and 100Bk is formed by forming a photoconductive layer made of a conductive layer and an organic photoreceptor (OPC) on the outer peripheral surface of a cylindrical base, and a driving source (not shown) Photoconductor drum 10Y comprising a photoconductor drum 10Y, 10M, 10C, 10Bk that is rotated counterclockwise by the power from the motor or following the intermediate belt 14a and the conductive layer is grounded, and a scorotron charger. Charging that is arranged in a direction orthogonal to the moving direction of 10M, 10C, and 10Bk and that gives a uniform potential to the surfaces of the photosensitive drums 10Y, 10M, 10C, and 10Bk by corona discharge having the same polarity as the toner. The photosensitive drums 10Y, 10M, 10C, and 10B by means 11Y, 11M, 11C, and 11Bk and a polygon mirror, for example. Exposure means 12Y for forming a latent image by performing image exposure on the surface of the uniformly charged photoreceptor drums 10Y, 10M, 10C, and 10Bk by scanning in parallel with the rotation axis of 12M, 12C, 12Bk and rotating developing sleeves 131Y, 131M, 131C, 131Bk, and developing means 13Y, 13M, for conveying the toner held thereon to the surfaces of the photosensitive drums 10Y, 10M, 10C, 10Bk 13C and 13Bk.

  Here, the image forming unit 100Y forms a yellow toner image, the image forming unit 100M forms a magenta toner image, and the image forming unit 100C forms a cyan toner image. According to the image forming unit 100Bk, a black toner image is formed.

  In such an image forming apparatus, the toner images of the respective colors formed on the photoconductive drums 10Y, 10M, 10C, and 10Bk of the image forming units 100Y, 100M, 100C, and 100Bk are transferred at the same timing. A color toner image is formed by sequentially transferring and superimposing on the material P by the transfer means 14Y, 14M, 14C, and 14Bk, and is transferred onto the transfer material P in a batch by the secondary transfer means 14b and separated. After being separated from the intermediate belt 14 a by 16 and fixed in the fixing device 17, it passes through the thermal energy applying means A and is finally discharged out of the apparatus from the discharge port 18.

The thermal energy applying means A used in the present invention is configured to retain or heat the heat-fixed visible image by heat transfer (except when the recording material is nipped and transported) , radiation, and convection . Any one is acceptable.
The thermal energy applying means may be provided at any position as long as it is subsequent to the fixing device. For example, the thermal energy applying means is provided in a passage of a recording material such as a transfer material between the fixing device and the discharge port 18.

The thermal energy application device, a heating chamber for heat insulation or heat against the recording material is provided, in the heating chamber, provided with a heating plate for performing heat transfer on the recording material or is passed through the heating plate above (recording material the sandwiching transported unless transfer heat.), or provided with a heat source for performing radiation for recording material, configuration and the like to or provided with a heating fan for performing convection for the recording material.
The heat source preferably uses electricity, and may be provided with a unique heat source that is used only for the thermal energy application unit, or may be configured to use exhaust heat obtained from any of the image forming apparatuses.

According to the study by the present inventors, the glossiness under low temperature heat fixing of 100 to 180 ° C. is determined by the fact that the surface of the visible image with the heat-fixed toner is coated with crystalline wax. It was important, and it was found that it would be effective if the crystal size of the crystalline wax covering the surface could be controlled. Depending on the crystal size of the crystalline wax, the surface roughness of the visible image by the heat-fixed toner varies greatly, and this surface roughness corresponds to the glossiness, that is, if the crystal of the crystalline wax is large. For example, if the surface roughness is large and gloss is not uneven and the crystal wax is small, if the crystal of the crystalline wax is small, the surface roughness is small and gloss is not uneven and the crystalline wax is It was found that the surface roughness is intermediate and the surface is semi-glossy with no gloss unevenness if the crystal size is intermediate between the above and the above.
In the present invention, the surface of the visible image is preferably coated with a crystalline wax to form a wax layer, more preferably 90% or more. The thickness of the wax layer is preferably 0.5 to 3 μm.

(Crystalline wax)
As the wax used for the toner in the present invention, a known crystalline wax can be used, and those having a melting point of 60 to 90 ° C. are particularly preferably used.
This is because the crystallization temperature of the wax correlates with the melting point of the wax, and by controlling the wax melting point within the above range, the controllability of the crystallization of the wax is enhanced at the fixing temperature of the present invention.

  Examples of the crystalline wax include polyolefin waxes such as polyethylene wax, long-chain hydrocarbon waxes such as paraffin wax and sazol wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, and trimethylolpropane. Tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, Ester wax such as tristearyl trimellitic acid, distearyl maleate, behenyl behenate, stynyl stearate, ethylenediamine dibehenyl amide, tri Such as amide-based waxes such as slit acid tristearyl amide.

A particularly preferably used wax is a combined system of a wax having a linear molecular structure such as paraffin wax and monoester wax and a wax having a branched chain structure such as microcrystalline wax. The proportion of the combined wax is preferably 2 to 60% of the wax containing a branched chain structure.
The amount of these waxes used is 1 to 20% by mass, preferably 3 to 10% by mass, based on the binder resin. If it is less than 1% by mass, the effect of preventing offset is insufficient, and if it exceeds 20% by mass, transferability and durability are deteriorated.

[Size of crystalline wax]
The size of the crystalline wax, that is, the crystal diameter is preferably 10 to 70 μm.
The size of the wax is measured using a laser microscope Vk-9510 (manufactured by Keyence Co., Ltd.) as a measuring instrument, taking a photograph 1000 times as large as the crystal diameter. The maximum length between any two points) is measured, and the number average value is taken as the average particle diameter.

[Average roughness on the image]
The average roughness on the image is represented by Rz and is preferably 1.5 to 1.0 μm.
As a measuring method of Rz, a wax crystal is observed using a laser microscope Vk-9510 (manufactured by Keyence Corporation), and a surface roughness on an arbitrary 2000 μm straight line in a field of view is measured by '94 JIS Rz / Rzjis to measure a ten-point average roughness. Measurement is performed as Rz according to the method.

[Glossiness of image]
As a method for measuring the glossiness of an image, a gloss meter “GMX-203” (manufactured by Murakami Color Research Laboratory Co., Ltd.) was used according to JIS Z 8741, and a 75 ° measuring square was selected and measured. The adhesion amount of the image to be measured is 12.0 ± 0.5 mg, and the transfer material is CF paper (manufactured by Konica Minolta Business Technologies). The glossiness is an average value of five points at the center and four corners of the measurement image.

The size of the crystalline wax crystal corresponding to the glossiness required by the user is determined in advance by the relationship between the crystalline wax crystal size and the surface roughness, and the relationship between the crystalline wax crystal size and glossiness of the visible image. And copying apparatus having thermal energy application means and control means based on this data may be designed.
The visible toner image according to the present invention as set forth in claims 1 to 9 can solve the problems of the present invention. On the other hand, the image forming method according to the previously proposed technique which is excellent in controlling the degree of gloss is as shown in a comparative example described later. The problem of the present invention cannot be solved under low temperature heat fixing of 100 to 180 ° C.

Hereinafter, the present invention will be described in further detail.
[Binder resin]
When the toner particles constituting the toner according to the present invention are produced by a pulverization method, a dissolution suspension method, or the like, a styrene resin, a (meth) acrylic resin, a styrene- ( (Meth) acrylic copolymer resins, vinyl resins such as olefin resins, polyester resins, polyamide resins, carbonate resins, polyethers, polyvinyl acetate resins, polysulfones, epoxy resins, polyurethane resins, urea resins, etc. Various known resins can be used. These can be used alone or in combination of two or more.

  In addition, when the toner particles constituting the toner according to the present invention are produced by suspension polymerization, miniemulsion polymerization aggregation, emulsion polymerization aggregation, or the like, the polymerizable unit for obtaining each resin constituting the toner is obtained. Examples of the monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2 , 4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, etc. Or styrene styrene derivative; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methacrylate Methacrylic acid such as isopropyl acid, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate Acid ester derivatives; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic acid Acrylic ester derivatives such as lauryl and phenyl acrylate; olefins such as ethylene, propylene, and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride Vinyl halides such as vinyl and vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl Vinyl ketones such as ketones; N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Vinyl compounds such as vinyl naphthalene and vinyl pyridine; Acrylic acids such as acrylonitrile, methacrylonitrile and acrylamide Or a vinyl-type monomer, such as a methacrylic acid derivative, can be mentioned. These vinyl monomers can be used alone or in combination of two or more.

  Moreover, it is preferable to use combining what has an ionic dissociation group as a polymerizable monomer. The polymerizable monomer having an ionic dissociation group has, for example, a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group, and specifically includes acrylic acid, methacrylic acid, maleic acid. Acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate And 3-chloro-2-acid phosphooxypropyl methacrylate.

  Furthermore, as a polymerizable monomer, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl A binder resin having a crosslinked structure can also be obtained using a polyfunctional vinyl such as glycol diacrylate.

[Surfactant]
When the toner particles constituting the toner according to the present invention are produced by a suspension polymerization method, a miniemulsion polymerization aggregation method or an emulsion polymerization aggregation method, the surfactant used for obtaining the binder resin is particularly limited. Sulfonate (sodium dodecylbenzene sulfonate, sodium arylalkylpolyether sulfonate), sulfate ester salt (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salt ( Ionic surfactants such as sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate and the like can be exemplified as suitable ones. Also, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester, etc. Nonionic surfactants can also be used. These surfactants are used as an emulsifier when a toner is obtained by an emulsion polymerization method, but may be used for other processes or purposes.

(Polymerization initiator)
When the toner particles constituting the toner according to the present invention are produced by suspension polymerization, miniemulsion polymerization aggregation or emulsion polymerization aggregation, the binder resin can be polymerized using a radical polymerization initiator.

  In the case of using the suspension polymerization method, an oil-soluble radical polymerization initiator can be used. Examples of the oil-soluble polymerization initiator include 2,2-azobis- (2,4-dimethylvaleronitrile) and 2,2-azo. Azo or diazo such as bisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile), 2,2-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile Polymerization initiators, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide , Lauroyl peroxide, 2,2-bis Examples thereof include peroxide polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in the side chain. .

  In the case of using the miniemulsion polymerization aggregation method or the emulsion polymerization aggregation method, a water-soluble radical polymerization initiator can be used, and the water-soluble radical polymerization initiator includes persulfates such as potassium persulfate and ammonium persulfate. Azobisaminodipropane acetate, azobiscyanovaleric acid and its salt, hydrogen peroxide and the like.

[Chain transfer agent]
It is generally used for the purpose of adjusting the molecular weight of the binder resin when the toner particles constituting the toner according to the present invention are produced by suspension polymerization, miniemulsion polymerization aggregation or emulsion polymerization aggregation. Chain transfer agents can be used.

  The chain transfer agent is not particularly limited. For example, mercaptans such as n-octyl mercaptan, n-decyl mercaptan, tert-dodecyl mercaptan, n-octyl-3-mercaptopropionate, terpinolene, carbon tetrabromide And α-methylstyrene dimer and the like are used.

[Colorant]
As the colorant constituting the toner according to the present invention, a known inorganic or organic colorant can be used. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

Examples of the colorant for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.
The above colorants can be used alone or in combination of two or more.

  The addition amount of the colorant is preferably 1 to 30% by mass, and more preferably 2 to 20% by mass with respect to the whole toner.

  As the colorant, a surface-modified one can also be used. As the surface modifier, conventionally known ones can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents and the like can be preferably used.

  In the present invention, the above crystalline wax is used as the wax, but as other waxes, solid silicone wax, higher fatty acid higher alcohol, montan ester wax, polypropylene wax and the like are within the range not impairing the effects of the present invention. Can be mixed and used.

[Flocculant]
When the toner particles constituting the toner according to the present invention are produced by the mini-emulsion polymerization aggregation method or the emulsion polymerization aggregation method, examples of the aggregation agent used for obtaining the binder resin include alkali metal salts and alkaline earth metals. Mention may be made of salts. Examples of the alkali metal constituting the flocculant include lithium, potassium, and sodium, and examples of the alkaline earth metal constituting the flocculant include magnesium, calcium, strontium, and barium. Of these, potassium, sodium, magnesium, calcium, and barium are preferable. Examples of the counter ion (anion constituting the salt) of the alkali metal or alkaline earth metal include chloride ion, bromide ion, iodide ion, carbonate ion and sulfate ion.

[Charge control agent]
The toner particles constituting the toner according to the present invention may contain a charge control agent as necessary. Various known compounds can be used as the charge control agent.

[Particle size of toner particles]
The particle diameter of the toner according to the present invention is preferably 3 to 8 μm in terms of the median diameter (D ₅₀ ) based on the number. When the toner particles are formed by a polymerization method, the particle size is controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself in the above-described toner manufacturing method. can do.

When the median diameter (D ₅₀ ) on the basis of the number is 3 to 8 μm, reproducibility of fine lines and high image quality of the photographic image can be achieved, and the amount of toner consumption is compared with the case where a large particle size toner is used. Can be reduced.

[Average circularity of toner particles]
The toner according to the present invention preferably has an average circularity represented by the following formula (3) of 0.930 to 1.000 for the individual toner particles constituting the toner from the viewpoint of improving transfer efficiency. More preferably, it is 0.950-0.995.
Equation (3); Average circularity = circumference of circle obtained from equivalent circle diameter / perimeter of particle projection image

(External additive)
The toner according to the present invention can be used by adding a so-called external additive for the purpose of improving fluidity, chargeability and cleaning property. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania and alumina, and these inorganic fine particles are preferably hydrophobized with a silane coupling agent or a titanium coupling agent. . As the organic fine particles, spherical particles having a number average primary particle diameter of about 10 to 2000 nm can be used. As the organic fine particles, polymers such as polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer can be used.

  The addition ratio of these external additives is preferably 0.1 to 5.0% by mass in the toner, and more preferably 0.5 to 4.0% by mass. In addition, various external additives may be used in combination.

[Toner Production Method]
The method for producing the toner according to the present invention is not particularly limited. As described above, the pulverization method, suspension polymerization method, miniemulsion polymerization aggregation method, emulsion polymerization aggregation method, dissolution suspension method, polyester molecule Examples of the method for producing the toner according to the present invention include an aqueous method in which a surfactant having a concentration equal to or lower than a critical micelle concentration called a miniemulsion method is dissolved. A dispersion solution is prepared by forming a droplet of a polymerizable monomer solution obtained by dissolving a release agent in a polymerizable monomer in a medium and forming oil droplets (10 to 1000 nm) using mechanical energy. It is preferable to use a method in which a water-soluble polymerization initiator is added to the obtained dispersion and the binder resin fine particles obtained by radical polymerization are associated (aggregated / fused) to obtain a toner.

  The reason for this is that since the polymerization is performed in the oil droplets, the toner particles are surely included in the binder resin in the toner particles, and therefore, until the fixing process is performed in the fixing device, that is, This is because it is considered that generation of a vaporizing component for the release agent is suppressed until heat is applied.

  In this miniemulsion polymerization aggregation method, instead of adding a water-soluble polymerization initiator, or while adding the water-soluble radical polymerization initiator, the oil-soluble radical polymerization initiator is added to the monomer solution. It may be added inside.

  As a method for producing the toner according to the present invention, the binder resin fine particles formed when the miniemulsion polymerization aggregation method is used may have a structure of two or more layers made of binder resins having different compositions. In this case, a polymerization initiator and a polymerizable monomer are added to a dispersion of the first resin particles prepared by a mini-emulsion polymerization process (first stage polymerization) according to a conventional method, and this system is polymerized (first process). Two-stage polymerization) can be employed.

As an example of the case of using the miniemulsion polymerization aggregation method as a method for producing the toner according to the present invention,
(1) Polymerizable monomer by dissolving or dispersing a crystalline wax as a release agent, a colorant and, if necessary, a toner particle constituent material such as a charge control agent in a polymerizable monomer as a binder resin. Dissolution / dispersion step for obtaining a solution (2) Polymerization step in which a polymerizable monomer solution is converted into oil droplets in an aqueous medium and a dispersion of binder resin fine particles is prepared by the miniemulsion method (3) The binder resin fine particles are aqueous Aggregation / fusion process for salting out, agglomerating and fusing in a medium to form agglomerated particles (4) Aging process for aging the agglomerated particles with thermal energy to adjust the shape and obtaining a dispersion of toner particles (5) Cooling step for cooling the dispersion of toner particles (6) Filtration / washing step for separating the toner particles from the cooled dispersion of toner particles and removing the surfactant from the toner particles (7) Washing Dry to dry the treated toner particles It comprised the step of adding an external additive to the step (8) the dried toner particles.

Hereinafter, each step will be described.
(1) Dissolution / dispersion step;
This step is a step of preparing a polymerizable monomer solution by dissolving or dispersing toner particle constituent materials such as a crystalline wax as a release agent and a colorant in the polymerizable monomer.

As the addition amount of the release agent, the content of the crystalline wax as the release agent in the finally obtained toner is preferably 1 to 30% by mass, more preferably 5 to 20% by mass. The amount is in the range.
In the polymerizable monomer solution, an oil-soluble polymerization initiator described below and / or other oil-soluble components can be added.

(2) polymerization step;
In a preferred example of this polymerization step, the above polymerizable monomer solution is added to an aqueous medium containing a surfactant having a concentration equal to or lower than the critical micelle concentration, and oil droplets are formed by applying mechanical energy. Then, a polymerization reaction is performed in the oil droplets by radicals from the water-soluble radical polymerization initiator. In the aqueous medium, resin particles may be added as core particles.

  In this polymerization step, binder resin fine particles containing a crystalline wax as a release agent and a binder resin are obtained. The binder resin fine particles may be colored or may not be colored. The colored binder resin fine particles can be obtained by polymerizing a monomer composition containing a colorant. Further, when using binder resin fine particles that are not colored, a dispersion of colorant fine particles is added to the dispersion of the binder resin fine particles in the aggregation step described later, and the binder resin fine particles and the colorant fine particles are added. Can be made into toner particles.

  Here, the “aqueous medium” means that the main component (50% by mass or more) is made of water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, are particularly preferable.

  The method of dispersing the polymerizable monomer solution in the aqueous medium is not particularly limited, but a method of dispersing by mechanical energy is preferable, and as a disperser for dispersing oil droplets by mechanical energy. Although there is no particular limitation, for example, “CLEAMIX”, an ultrasonic disperser, a mechanical homogenizer, a manton gourin, a pressure homogenizer, and the like can be given. The dispersed particle diameter is 10 to 1000 nm, preferably 30 to 300 nm.

  Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited, and the stirring device “CLEARMIX” (M Technique Co., Ltd.) equipped with a rotor that rotates at high speed. Product), an ultrasonic disperser, a mechanical homogenizer, a manton gourin, a pressure homogenizer, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 30 to 300 nm.

(3) Aggregation / fusion process;
In the agglomeration / fusion process, a dispersion of colorant fine particles is added to the dispersion of binder resin fine particles obtained by the above polymerization step if the binder resin fine particles are not colored. The resin particles are salted out, aggregated and fused together with the colorant particles in an aqueous medium. In the middle stage of the aggregation / fusion process, binder resin fine particles having different resin compositions can be added and aggregated.

  In the agglomeration / fusion step, internal additive particles such as a charge control agent may be fused together with the binder resin fine particles and the colorant fine particles.

  A preferred agglomeration / fusion method is to add a salting-out agent comprising an alkali metal salt and / or an alkaline earth metal salt in a water-based medium in which the binder resin fine particles and the colorant fine particles are present to a critical aggregation concentration or higher. Addition as a flocculant, and then proceed to salting out by heating to a temperature above the glass transition temperature of the binder resin fine particles and above the melting peak temperature of the crystalline wax as the release agent to be used At the same time, the coagulation and fusion are performed.

  In this aggregation / fusion process, it is necessary to quickly raise the temperature by heating, and the temperature raising rate is preferably 1 ° C./min or more. The upper limit of the rate of temperature rise is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid salting-out, aggregation and fusion.

  Furthermore, after the dispersion of the binder resin fine particles and the colorant fine particles reaches a temperature equal to or higher than the glass transition temperature and equal to or higher than the melting peak temperature of the crystalline wax as a release agent, the temperature of the dispersion is maintained for a certain time. Therefore, it is important to continue salting out, aggregation and fusion. As a result, toner particle growth (aggregation of binder resin fine particles and colorant fine particles) and fusion (disappearance of the interface between the particles) can be effectively advanced, and the durability of the finally obtained toner can be improved. Can be improved.

  The dispersion of the colorant fine particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant fine particles is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for dispersing the colorant fine particles is not particularly limited, but is preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gourin or a pressure homogenizer, a sand grinder, a Getzmann mill, or a diamond fine mill. Media type dispersers.

  The colorant fine particles may be surface-modified. Specifically, by dispersing the colorant fine particles in a solvent, adding the surface modifier to the dispersion, and heating the system. After the reaction, and after the reaction is completed, the colorant fine particles are separated by filtration, washed and filtered with the same solvent, and then dried to obtain the colorant fine particles treated with the surface modifier.

(4) Aging process;
The aging step is preferably performed by thermal energy (heating).
Specifically, by heating and stirring a system containing aggregated particles, toner particles are adjusted by adjusting the heating temperature, stirring speed, and heating time until the shape of the aggregated particles reaches a desired average circularity. .

  In this ripening step, the toner particles may be used as core particles, and binder resin fine particles may be further added to adhere and fuse to the core particles, thereby obtaining a core-shell structure. In this case, it is preferable that the glass transition temperature of the binder resin fine particles constituting the shell layer is higher by 20 ° C. or more than the glass transition temperature of the binder resin fine particles constituting the core particle.

  In addition, the binder resin fine particles used in the agglomeration / fusion process described above are a resin (hydrophilic resin) made of a polymerizable monomer having an ionic dissociation group, which will be described later, and a polymerization without an ionic dissociation group. In the case of being configured to contain a resin (hydrophobic resin) that uses only a hydrophilic monomer as a raw material, in this aging step, the hydrophilic resin is on the surface of the aggregated particles, and the hydrophobic resin is on the aggregated particles. The toner particles having a core-shell structure can be formed by orienting to the inner side of the toner.

(5) cooling step;
This cooling step is a step of cooling the toner particle dispersion. The cooling rate in the cooling process is 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

(6) Filtration and washing process;
In this filtration / washing step, a filtration process is performed in which the toner particles are solid-liquid separated from the dispersion of the toner particles cooled to a predetermined temperature in the above step and filtered, and the filtered toner particles (cake-like aggregate) And a cleaning treatment for removing the deposits such as a surfactant and a salting-out agent and the alkali agent used in the aging step.

  Here, the washing treatment is performed by washing with water until the electric conductivity of the filtrate reaches 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche, and a filtration method using a filter press, and are not particularly limited.

(7) drying step;
In this step, the washed toner cake is dried to obtain dried toner particles. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like. The moisture of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less. In addition, when the toner particles subjected to the drying treatment are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(8) External processing step;
In this step, an external additive is added to the dried toner particles as necessary. As a mixing device used for adding the external additive, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used.

(Developer)
The toner according to the present invention may be used as a magnetic or non-magnetic one-component developer, or may be mixed with a carrier and used as a two-component developer. When the toner according to the present invention is used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner is used. Any of which can be used. In the case where the toner according to the present invention is used as a two-component developer, the carrier may be a conventionally known metal such as iron, ferrite, or magnetite, or an alloy of such metal with a metal such as aluminum or lead. Magnetic particles made of a material can be used, and ferrite particles are particularly preferable. As the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a resin-dispersed carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

  The coating resin constituting the coat carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluorine-containing polymer resins. Moreover, it does not specifically limit as resin which comprises a resin dispersion type carrier, A well-known thing can be used, For example, a styrene-acrylic-type resin, a polyester resin, a fluororesin, a phenol resin etc. can be used.

  A preferable carrier is a coated carrier coated with a styrene-acrylic resin-based resin as a coating resin from the viewpoint of prevention of detachment of external additives and durability.

The median diameter (D ₅₀ ) based on the volume of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The median diameter (D ₅₀ ) based on the volume of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. it can.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Production Example 1 of resin particle dispersion]
(First stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device was charged with a solution prepared by dissolving 8 g of sodium dodecyl sulfate in 3 L of ion-exchanged water and stirred at a stirring speed of 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C. After the temperature rise, a solution in which 10 g of potassium persulfate was dissolved in 200 g of ion-exchanged water was added, the temperature was again set to 80 ° C., 480 g of styrene, 250 g of n-butyl acrylate, 68.0 g of methacrylic acid and n-octyl-3- Polymeric monomer solution containing 16.0 g of mercaptopropionate was added dropwise over 1 hour, then polymerized by heating and stirring at 80 ° C. for 2 hours, and resin particle dispersion containing resin particles (1h) A liquid (1H) was prepared.

(Second stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device was charged with a solution prepared by dissolving 7 g of sodium polyoxyethylene-2-dodecyl ether sulfate in 800 ml of ion-exchanged water and heated to 98 ° C. 260 g of the above resin particle dispersion (1H), 245 g of styrene, 120 g of n-butyl acrylate, 1.5 g of n-octyl-3-mercaptopropionate, 180 g of paraffin wax, “HNP-190” (Nippon Seiki Co., Ltd.) 9 g, melting point 80 ° C.) 9 g, “HNP-11” (manufactured by Nippon Seiki Co., Ltd., melting point 64 ° C.) 78 g of a polymerizable monomer solution dissolved at 90 ° C. is added, and mechanical dispersion having a circulation path A dispersion liquid containing emulsified particles (oil droplets) was prepared by mixing and dispersing for 1 hour using a machine “CREARMIX (manufactured by M Technique)”.
Next, an initiator solution in which 6 g of potassium persulfate was dissolved in 200 ml of ion-exchanged water was added to this dispersion, and the system was heated and stirred at 82 ° C. for 1 hour to polymerize the resin particles (1 hm ) Containing resin particle dispersion (1HM) was prepared.

(3rd stage polymerization)
A solution prepared by dissolving 11 g of potassium persulfate in 400 ml of ion-exchanged water was added to the above resin particle dispersion (1HM), and styrene 435 g, n-butyl acrylate 130 g, methacrylic acid 33 g and n were added at a temperature of 82 ° C. -A polymerizable monomer solution consisting of 8 g of octyl-3-mercaptopropionate was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain a resin particle dispersion A containing resin particles a. When the particle diameter of the resin particles a in the resin particle dispersion A was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 150 nm. Moreover, it was 45 degreeC when the glass transition point temperature of this resin particle a was measured. The obtained resin particle dispersion was designated as resin particle dispersion 1.

[Production Example 2 of resin particle dispersion]
The release agent of the resin particle dispersion 1 is changed to 9 g of “HNP-0190” (manufactured by Nippon Seiki Co., Ltd., melting point 80 ° C.) and 78 g of “FNP-0090” (manufactured by Nihon Seiki Co., Ltd., melting point 87.9 ° C.). Otherwise, a resin particle dispersion 2 was obtained in the same manner.

[Production Example 1 of Colorant Fine Particle Dispersion]
While stirring a solution obtained by dissolving 90 g of sodium dodecyl sulfate in 1600 ml of ion-exchanged water, 420 g of carbon black “Regal 330R” (manufactured by Cabot) is gradually added, and then a stirrer “Clearmix” (M Technique Co., Ltd.). A dispersion liquid Q of colorant fine particles was prepared. The particle diameter of the colorant fine particles in the dispersion liquid Q of the colorant fine particles was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), and the volume-based median diameter was 110 nm. It was.

[Production Example 2 of Colorant Fine Particle Dispersion]
420 g of carbon black was added to C.I. I. A dispersion R of fine colorant particles was prepared in the same manner as in Production Example 1 of a fine particle dispersion, except that Pigment Yellow 74 was replaced with 310 g. When the particle diameter of the colorant fine particles in the colorant fine particle dispersion R was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 150 nm. It was.

[Production Example 3 of Colorant Fine Particle Dispersion]
420 g of carbon black was added to C.I. I. A dispersion S of colorant fine particles was prepared in the same manner as in Production Example 1 of a dispersion of colorant fine particles, except that Pigment Red 122 was replaced with 310 g. When the particle diameter of the colorant fine particles in the colorant fine particle dispersion S was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the volume-based median diameter was 150 nm. It was.

[Production Example 4 of Colorant Fine Particle Dispersion]
420 g of carbon black was added to C.I. I. A dispersion T of colorant fine particles was prepared in the same manner as in Production Example 1 of a dispersion of colorant fine particles, except that Pigment Blue 15 was replaced with 310 g. The particle diameter of the colorant fine particles in the colorant fine particle dispersion T was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), and the volume-based median diameter was 150 nm. It was.

[Production Example 1 of Toner Particles]
300 g of resin particle dispersion 1 in terms of solid content, 1400 g of ion-exchanged water, and 120 g of dispersion liquid Q of colorant fine particles are placed in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device. Then, a solution prepared by dissolving 3 g of sodium polyoxyethylene-2-dodecyl ether sulfate in 120 ml of ion-exchanged water was added, the liquid temperature was adjusted to 30 ° C., and the pH was adjusted to 10 by adding a 5N aqueous sodium hydroxide solution. . Next, an aqueous solution in which 35 g of magnesium chloride was dissolved in 35 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring, and the temperature was raised after holding for 3 minutes. The particle growth reaction was continued while maintaining the temperature at 90 ° C. In this state, the particle size of the associated particles is measured with “Coulter Multisizer III”, and when the desired particle size is reached, an aqueous solution in which 150 g of sodium chloride is dissolved in 600 ml of ion-exchanged water is added to increase particle growth. Further, the fusion between the particles was allowed to proceed until the average circularity was 0.965 as measured by “FPIA-2100” by stirring and heating at a liquid temperature of 98 ° C. as a fusion process. Thereafter, the solution was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 4.0, and stirring was stopped.

  The toner particles generated in the above process are solid-liquid separated with a basket-type centrifuge “MARK III model number 60 × 40” (manufactured by Matsumoto Kikai Co., Ltd.) to form a wet cake of toner particles. The basket-type centrifuge was washed with ion exchange water at 45 ° C. until the electric conductivity of the filtrate reached 5 μS / cm, and then transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). The toner particles were obtained by drying until the mass was reached.

  To the toner particles, 1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size = 20 nm) are added and mixed with a Henschel mixer. Toner 1Bk composed of toner particles 1Bk was produced. Note that the shape and particle size of these toner particles did not change depending on the addition of hydrophobic silica and hydrophobic titanium oxide.

Example
[Production Example 2 of Toner Particles]
A toner 2Bk was produced in the same manner as in Toner Particle Production Example 1 except that the resin particle dispersion 1 was changed to the resin particle dispersion 2.

(Developer adjustment)
Next, a ferrite carrier having a volume average particle size of 50 μm coated with a silicone resin was mixed with each of the prepared toners to prepare “Developers 1 and 2” having a toner concentration of 6%.

(Evaluation)
Evaluation was performed using a commercially available color multifunction peripheral “bizhubPRO C450” (manufactured by Konica Minolta Business Technologies) as an evaluation machine using an apparatus improved so that an image after fixing passes on a hot plate.
Regarding the comparative example which does not use a hot plate, the following evaluation conditions shall be followed.

As the conditions of the hot plate serving as the thermal energy application means, as shown in Table 1, the set temperature and passage time on the hot plate can be adjusted to levels 1 to 3, and the image glossiness is adjusted. Each of the developers 1 and 2 was mounted on an evaluation machine, the thermal energy was applied as shown in Table 2, the following evaluation was performed, and the controllability of glossiness without glossiness unevenness was evaluated. The results are also shown in Table 2.
The wax crystal diameter and surface roughness shall be in accordance with the above-described measurement method.

(Comparative Example 1)
In the image forming method of Example 3, the cooling fan is used as a cooling means without applying thermal energy application means after the fixing step, and the speeds are 60 ° C./min, 45 ° C./min, and 30 ° C./min as shown in Table 2, respectively. An image was formed in the same manner except that it was cooled in step 1 to obtain an image. Although the glossiness can be controlled to some extent, it is a result that uneven glossiness occurs.

(Comparative Example 2)
In the image forming method of Example 3, the fixing temperature was changed to adjust the glossiness, and after the fixing step, the image was formed in the same manner except that it was left to room temperature without applying thermal energy application means to obtain an image. It was. Although the glossiness unevenness was acceptable, controllability from no gloss to high gloss could not be obtained even if the fixing temperature was greatly changed due to poor controllability of gloss.

(Glossiness)
As for the glossiness of the fixed image, a superposed solid pattern is output from a multicolor toner having a toner adhesion amount of 12.5 ± 0.5 g / m ² , and a gloss meter “GMX-203” (Murakami Color Technology) is applied according to JIS Z 8741. Using a laboratory), a 75 ° measuring square was selected and measured. The glossiness is an average value of five points at the center and four corners of the measurement image.

The adhesion amount of the image to be measured is 12.0 ± 0.5 mg, and the transfer material is CF paper (manufactured by Konica Minolta Business Technologies).
It should be noted that if the gloss level difference was 10 or more in the gloss mode and the non-gloss mode, it was determined that the gloss level could be changed sufficiently.

(Glossiness unevenness)
A superimposed solid pattern was produced with multicolor toner having a toner adhesion amount of 12.5 ± 0.5 g / m ² , and the state of uneven gloss was visually evaluated.
○: The difference between the maximum glossiness and the minimum glossiness is hardly known;
Δ: There is a slight difference between the maximum glossiness and the minimum glossiness, but there is no practical problem;
X: The difference between the maximum glossiness and the minimum glossiness is clear, and there are practical problems.

  The present invention can be widely used in image forming methods such as electrophotography, electrostatic printing, and magnetic recording.

Explanatory drawing which shows an example of the image forming apparatus used for the image forming method by the toner of this invention.

Explanation of symbols

10Y, 10M, 10C, 10Bk Photosensitive drum 11Y, 11M, 11C, 11Bk Charging means 12Y, 12M, 12C, 12Bk Exposure means 13Y, 13M, 13C, 13Bk Developing means 131Y, 131M, 131C, 131Bk Developing sleeve 14a Intermediate belt 16 Separating means 17 Fixing device 18 Discharge port 100Y, 100M, 100C, 100Bk Image forming unit A Thermal energy applying means P Transfer material

Claims (3)

In an image forming method in which a visible image formed with a toner containing a binder resin, a colorant, and a wax is heat-fixed on a recording material,
The heating and fixing temperature is 100 to 180 ° C., and the visible image heat-fixed at this temperature is kept at a temperature equal to or lower than the melting point temperature of the crystalline wax contained in the toner, and is applied to the recording material . heat transfer (the recording material was pinched and conveyed unless transfer heat.), radiation or by the application of thermal energy by convection, by controlling the crystal size of the crystalline wax, images formed Ru changing the glossiness A method ,
The image forming method, wherein the crystalline wax has a melting point of 60 to 90 ° C. 2. The image forming method according to claim 1, wherein the heat retention or heating time for applying thermal energy is 10 to 20 minutes. 3. The image forming method according to claim 1, wherein the application of thermal energy is performed in a heating chamber provided at a subsequent stage of a fixing device for heating and fixing the visible image on the recording material.

Images