JPH11344835A - Color toner for developing electrostatic image, and developer and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a yellow color toner for developing electrostatic image superior in transparency of an OHP image even in oilless fixation, less liable to a hue change of the transmission color and superior also in light resistance by incorporating a vinyl polymer synthesized using a specified monomer as a bonding resin and at lest a specified compd. as a colorant. SOLUTION: This yellow color toner contains a vinyl polymer synthesized, using at least one of a monomer represented by formula I and a monomer represented by formula II as a bonding resin and at least a compd. represented by formula III as a colorant. In the formulae, R1 -R8 are each H, halogen or the like, R9 -R12 are each H or 1-6C chain or cyclic alkyl, R13 and R14 are each H, 1-19C alkyl or the like, X and Y are each 1-6C chain alkylene or the like, (n) is an integer of 1-5, and (m) is an integer of 3-20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner and a developer for developing an electrostatic image used in an electrophotographic color copying machine, a color printer, electrostatic recording, electrostatic printing, and the like, and image formation using the same. It is about the method.

[0002]

2. Description of the Related Art In general, in an electrophotographic method, a photosensitive member having a photosensitive layer made of a photoconductive material is provided with a uniform electrostatic charge, and is then subjected to image exposure to electrostatically charge the surface of the photosensitive member. A latent image is formed, this electrostatic latent image is developed with a developer to form a toner image, and the obtained toner image is transferred to a transfer material such as paper, and then fixed by heating or pressure fixing to copy. An image is formed. As the photoconductor, a selenium photoconductor, an organic photoconductor, an amorphous silicon photoconductor, or the like is used.

As a developer used for developing an electrostatic latent image formed on the surface of a photoreceptor, a one-component developer and a two-component developer are generally known. Usually, the one-component developer is composed of a magnetic toner in which a magnetic material or the like is dispersed in a binder resin,
The two-component developer is composed of a toner and a carrier composed of magnetic particles.

A two-component developer is excellent in fluidity and triboelectricity as compared with a one-component developer, is capable of forming a high-quality image, and is used more frequently than a one-component developer.

In recent years, the colorization of documents, images, and the like has rapidly progressed, and there is an urgent need to improve the quality of color images. One of the requirements for high quality color images is O
HP (overhead projector) image transparency.

Conventionally, in order to improve the transparency of an OHP image, a technique of reducing light scattering on the image surface by smoothing (glossing) the image surface has been used.

However, the conventional method has a problem that it is difficult to distinguish characters in a business document or the like because the image surface is glossy.

Further, it is necessary to lower the melt viscosity of the toner in order to smooth the surface of the fixed toner, and it is necessary to apply a large amount of oil to the fixing roller in order to improve the hot offset resistance during fixing. there were. This leads to an increase in size, complexity and cost of the device.

On the other hand, in the case of a non-glossy image, a document or the like is very easy to read, but there is a problem that transparency of the OHP image is inferior due to much light scattering on the image surface. However, in the case of a non-gloss image design, there is an advantage that the hot offset resistance can be satisfied by the wax having a high melt viscosity of the toner. Therefore, only a small amount of oil is applied to the fixing roller (oil-less fixing), and the apparatus can be reduced in size, simplified, and reduced in cost.

Further, in the conventional toner, an insoluble pigment is mainly used as a colorant, and dispersed particles of several tens to several hundreds of nm are formed. There is also a problem that the transparency of the OHP image is inferior due to scattering.

For example, C.I. described in JP-A-2-210363 and JP-A-62-157051. I. Pi
gment Yellow 12, 13, 14, 16,
Disazo pigments such as C.17 and C.I. I. Pigment Yellow
When a toner using a pigment such as ow 185 is used, the pigment is insoluble and easily aggregates to form secondary and tertiary particles to form dispersed particles of several tens to several hundreds of nm. And the change in the hue of the transmitted color is a problem. As a countermeasure, pigments are used in advance as a coloring material processed by a flushing method or a masterbatch method. I can't escape.

On the other hand, when a dye is used as the colorant, the transparency of the OHP image is excellent because the dye is sufficiently dissolved in the toner resin particles, and the change in the hue of the transmitted color is small. It is difficult to maintain the color tone of an image for a long time. C.I. described in JP-A-3-276161. I. SOLVENT YELLOW 16
2, C.I. described in JP-A-2-207274. I. DIRECTYELLOW 160;
C.-207273. I. SOL
Dyes such as VENT YELLOW 112 are known, but OHP images of toners using these dyes have high transparency and little change in hue, but are inferior to pigments in light resistance and maintain stable performance for a long time. Can not.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an oil which can be reduced in size because the hot offset resistance does not decrease due to the low melt viscosity of the toner and a large amount of oil is not applied. A yellow toner for developing an electrostatic image with excellent transparency of an OHP image, a small change in the hue of a transmitted color, and excellent light fastness even under a low fixing condition;
An object of the present invention is to provide a developer and an image forming method using the same.

[0014]

The object of the present invention is achieved by adopting the following constitution.

(1) An electrostatic image containing, as a binder resin, a vinyl polymer synthesized using at least one of a monomer represented by the following general formula (a) and a monomer represented by the following general formula (b): A color toner for developing an electrostatic image, which comprises at least the following compound (c) as a coloring agent.

[0016]

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[0017] In the formula (a), each R ₁ to R ₈ represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or an aryl group, R ₉ And R ₁₀ each represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, and X represents a chain alkylene group having 1 to 6 carbon atoms, a polymethylene group, or a carbon atom having 2 to 6 carbon atoms. A chain or cyclic alkylidene group of 6 or a mere bond, Y is a chain alkylene group having 1 to 6 carbon atoms, a polymethylene group, a chain or cyclic alkylidene group having 2 to 10 carbon atoms,
Represents an aryl-substituted alkylidene group, a sulfonyl group, a sulfide group or —O—, or represents a mere bond. n represents an integer of 1 to 5.

In the general formula (b), R ₁₁ and R ₁₂ each represent a hydrogen atom or a chain or cyclic alkyl group having 1 to 6 carbon atoms, and R ₁₃ and R ₁₄ each represent a hydrogen atom or a carbon atom. Represents a substituted or unsubstituted alkyl group, cycloalkyl group or aryl group having 1 to 10 atoms (R ₁₃ and R ₁₄ may be the same or different, and R ₁₃ and R ₁₄ To form a ring). m represents an integer of 3 to 20.

(2) A developer prepared by mixing the color toner for developing an electrostatic image described in (1) and a carrier.

(3) An image forming method for forming a color image by charging, exposing, and developing using the color toner for developing an electrostatic image described in (1).

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The toner colorant for electrostatic image development of the present invention comprises C.I. I. SOLVENT Y
ELLOW 93 is used in an amount of 0.01 to 15 parts by weight, preferably 1.0 to 10 parts by weight, based on 100 parts by weight of the binder resin.

In the toner for developing an electrostatic image of the present invention, a main polymerization component composed of various vinyl monomers is used in combination with at least one of a specific bifunctional acrylic compound and a bifunctional methacrylic compound. A vinyl polymer having a crosslinked structure obtained by copolymerization with a crosslinkable component is contained as a binder resin.

When the obtained polymer is used as a binder resin for a toner, the vinyl monomer as the main polymerizable component is
It is preferable that the styrene-based monomer or the acrylate or methacrylate monomer be used as a main component so that the toner can reliably obtain necessary basic characteristics such as charging characteristics and pulverizability.

Specific examples of the styrene monomer include styrene, o-methylstyrene, p-methylstyrene and α-methylstyrene.
Methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-ter-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, P-chlorostyrene, 3,4-dichlorostyrene and the like.

Specific examples of the acrylate or methacrylate monomers include methyl acrylate, ethyl acrylate, propyl acrylate and n-acrylate.
Butyl, isobutyl acrylate, n-octyl acrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl acrylate, methyl methacrylate,
In addition to acrylic acid or methacrylic alkyl esters such as ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, and stearyl methacrylate, 2-chloroethyl acrylate, acrylic Phenyl acrylate, methyl α-chloroacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, glycidin methacrylate, bisglycidyl methacrylate, polyethylene glycol dimethacrylate, methacryloxyethyl phosphate, etc. Can be mentioned.

Among these, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like are particularly preferably used.

In the present invention, a vinyl monomer other than those described above can be used as a main polymerization component or a part of a crosslinkable component. Specific examples thereof include acrylic acid, methacrylic acid, and α-ethylacrylic acid. Unsaturated dicarboxylic acids such as crotonic acid, fumaric acid, maleic acid, citraconic acid, itaconic acid and monoester derivatives and diester derivatives thereof; monoacryloyloxyethyl succinate, monomethacryloyloxyethyl succinate, monofumarate Acryloyloxyethyl ester fumaric acid monomethacryloyloxyethyl ester, acrylonitrile, methacrylonitrile, acrylamide and the like can be mentioned.

In the present invention, the polymer constituting the binder resin of the toner is formed from a bifunctional acrylic compound and a bifunctional methacrylic compound represented by the following general formulas (a) and (b). At least one selected is introduced as a crosslinkable component.

[0030]

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[0031] In the formula (a), each R ₁ to R ₈ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or an aryl group, R ₉ And R ₁₀ each represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, and X represents a chain alkylene group having 1 to 6 carbon atoms, a polymethylene group, or a carbon atom having 2 to 6 carbon atoms. A chain or cyclic alkylidene group of 6 or a mere bond, Y is a chain alkylene group having 1 to 6 carbon atoms, a polymethylene group, a chain or cyclic alkylidene group having 2 to 10 carbon atoms,
Represents an aryl-substituted alkylidene group, a sulfonyl group, a sulfide group or —O—, or represents a mere bond. n represents an integer of 1 to 5.

In the general formula (b), R ₁₁ and R ₁₂ each represent a hydrogen atom or a chain or cyclic alkyl group having 1 to 6 carbon atoms, and R ₁₃ and R ₁₄ each represent a hydrogen atom or a carbon atom. Represents a substituted or unsubstituted alkyl group, cycloalkyl group or aryl group having 1 to 10 atoms (R ₁₃ and R ₁₄ may be the same or different, and R ₁₃ and R ₁₄ To form a ring). m represents an integer of 3 to 20.

In the above, examples of the substituent include an alkyl group such as a methyl group and an ethyl group, a halogen atom such as a chlorine atom and a fluorine atom, a hydroxyl group, a silyl group, a siloxy group,
Refers to an aryl group such as a phenyl group.

When a crosslinkable monomer having n of 6 or more in the general formula (a) is used, in the obtained polymer, a segment formed by the crosslinkable monomer is excessively soft-segmented, so that sufficient mechanical strength as a binder resin is obtained. Can not be obtained.

Further, when a crosslinkable monomer having m of 2 or less in the general formula (b) is used, in the polymer obtained, the brittleness is manifested without the segment formed by the crosslinkable monomer becoming a sufficient soft segment. , M is 21 or more, a sufficient mechanical strength cannot be obtained due to excessive soft segmentation.

The proportion of the crosslinkable component represented by the general formula (a) and / or the general formula (b) is from 0.1 to 10% by weight, preferably from 0.3 to 6% by weight based on the obtained polymer. weight%
It is. If the proportion is less than 0.1% by weight, a sufficient effect by the crosslinkable component may not be obtained. If the proportion is more than 10% by weight, the obtained polymer may have too high a degree of crosslinking, so There is a possibility that the fluidity becomes low and good low-temperature fixability of the toner cannot be obtained.

Examples of the compound represented by the general formula (a) include the following.

[0038]

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[0039]

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[0040]

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[0041]

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Examples of the compound represented by formula (b) include the following.

[0043]

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[0044]

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In the binder resin of the toner of the present invention, when an unsaturated carboxylic acid such as acrylic acid or methacrylic acid is contained as a copolymer component, the mechanical strength of the toner is improved and the stability of image density is improved. It is more preferable because it improves. The amount used is preferably 2 to 10% by weight of the whole polymer. If the use amount is less than 2% by weight, the effect of adding the acid component is small and the improvement in mechanical strength is not recognized, and the effect of improving the change in image density becomes insufficient.
When the amount is more than 10% by weight, the mechanical strength is improved, and the change in image density is improved. However, the obtained polymer itself is hard, so that a suitable fixing property cannot be obtained, and good visibility is obtained. Images may not be obtained.

The polymer constituting the binder resin in the toner of the present invention may have an ion-crosslinked structure. In order to introduce an ionic cross-linking structure, a polyvalent metal compound may be reacted, whereby an ionic cross-linking structure is formed by a coordination bond (ion bond) between a carboxyl group of a vinyl polymer and a metal ion. . Here, as preferred polyvalent metal compounds, for example, acetates and oxides of alkaline earth metals and zinc group metals can be mentioned. The amount used is 0.5% by weight or less of the whole polymer,
It is preferably 0.5 part by weight or less based on 100 parts by weight of the vinyl binder resin. If the amount is more than 0.5% by weight, the resulting polymer has too high a degree of crosslinking, so that the toner has a low fluidity at the time of melting and thus has poor fixability, and a good image is obtained. It may not be possible to get it.

The polymer of the binder resin in the present invention desirably has a transition temperature (Tg) of 45 ° C. or higher, since non-aggregation is obtained in the toner. Polymerization methods for producing such polymers include suspension polymerization, emulsion polymerization,
Solution polymerization, bulk polymerization and the like can be used.

The toner of the present invention may contain a polyolefin. Specific examples of the polyolefin include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, 3-methyl-1-butene, 3-methyl-2-pentene, and 3-propyl-5-methyl-2. Polymers of olefin monomers such as -hexene or copolymers of these olefin monomers with acrylic acid, methacrylic acid, vinyl acetate and the like can be mentioned, and polypropylene is particularly preferable.

The polyolefin is contained in the toner in an amount of 0.5 to 1%.
It is preferred to be added at a ratio of 0% by weight, especially 1 to 5% by weight. If it is less than 0.5% by weight, the fixing strength of the toner,
There is a tendency that the fixing characteristics such as offset in the heat roll fixing method are inferior. On the other hand, if it exceeds 10% by weight, the fluidity of the toner tends to be inferior, so that the image quality is deteriorated due to poor flow of the developer, and the toner or the developer stays in the container. Is easy to occur.

A fluidizing agent can also be added to the toner. For example, inorganic oxides such as silica (SiO ₂ ) or titania (TiO ₂ ) having a hydrophobic surface, silicon carbide (Si)
Inorganic fine particles such as C), metal soap of zinc stearate,
Other known materials can be used.

In the toner of the present invention, a conventionally known charge control agent can be used, but a colorless or white toner is preferably used for color toner particles. Specific examples of such preferred charge control agents include zinc salts of salicylic acid derivatives.

As a developing method, a one-component developing method using only the toner of the present invention as a developer or a two-component developing method by mixing with a carrier can be used. However, it is more preferable to use the two-component developer in a two-component development system because the chargeability is stable and the color purity is not reduced because the toner is used as a color toner.

In this case, the carrier used is iron,
Although an uncoated carrier composed of only magnetic material particles such as ferrite and magnetite may be used, it is more preferable to use a resin-coated carrier in which the surface of the magnetic material particles is coated with a resin or the like. The average particle diameter of these carriers is usually 30 to 150 μm in volume average particle diameter.

In the development, non-contact development is also performed.
It can also be used for contact development.

Further, the image forming method can be used without any particular limitation. However, since it is usually used in a color image forming method, as a typical example, charging, exposure and development are repeated to form a plurality of different colored hues. An example of an image forming method in which an image obtained by superimposing a toner image using an agent is formed on a photoconductor and the image is collectively transferred to a fed image support will be described below.

FIG. 1 shows a cross-sectional structure of a color printer which is an example of an apparatus according to an image forming method used in the present invention. In this color printer, toner images of respective colors sequentially formed on a photosensitive drum (image carrier) are superimposed, and then transferred once on a recording sheet by a transfer unit to form a color image. Is a color image forming apparatus that separates from an image bearing member surface.

In the figure, reference numeral 10 denotes a photosensitive drum serving as an image carrier, which is formed by applying an OPC photosensitive member (organic photosensitive member) on a drum substrate, and is grounded and driven to rotate clockwise in the figure. 12 is a scorotron charger, a uniform charging of the V _H the photosensitive drum 10 peripheral surface, is given by a corona discharge by a grid and the corona discharge wire which is the potential held in the V _G. Prior to charging by the scorotron charger 12, in order to eliminate the history of the photoconductor up to the previous printing, exposure is performed by a PCL (pre-charging static eliminator) 11 using a light emitting diode or the like, and the peripheral surface of the photoconductor is neutralized. deep.

After the photosensitive drum 10 is uniformly charged, the image exposure means 13 performs image exposure based on the image signal. The image exposing means 13 is a device which uses a laser diode (not shown) as a light emitting light source, rotates a polygon mirror 131, an fθ lens 132, a cylindrical lens 133, and bends an optical path by a reflection mirror 134 to perform main scanning.
A latent image is formed by this and the rotation (sub-scan) of the photosensitive drum 10. In this example, the character portion is exposed,
An inverted latent image is formed such that the character portion has a lower potential _VL .

Around the periphery of the photosensitive drum 10, developing devices 14 (14Y) each containing a developer containing a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier are provided. , 14M, 14C, and 14K). First, the developing sleeve 14 for developing the first yellow color has a built-in magnet and rotates while holding the developer.
1 is performed. The developer is a carrier in which ferrite is magnetic material particles and an insulating resin is coated around the magnetic material particles. A colorant (compound (c) is yellow), a charge controlling agent, and a colorant corresponding to the color are mainly composed of a vinyl polymer resin. , And a toner to which titanium oxide and the like are added.
The developer is applied onto the developing sleeve 141 by the layer forming means.
It is regulated to a layer thickness (developer) of 00 to 600 μm and transported to the development area.

[0060] As 0.2~1.0mm gap is greater than the layer thickness (developer) to the developing sleeve 141 in the developing zone between the photosensitive drum 10, the DC bias of the AC bias and V _DC of V _AC during which It is superimposed and applied. V _DC and V _H, for charging the toner are the same polarity, the toner given the opportunity to leave from the carrier by V _AC and V
It does not adhere to the _VH portion having a higher potential than DC, but adheres to the _VL portion having a lower potential than _VDC , thereby performing visualization (reversal development).

After the visualization of the first color is completed, the image forming process for the magenta of the second color is started, and the scorotron charger 1 is again activated.
2, and a latent image based on the image data of the second color is formed by the image exposure unit 13.

Again, a portion of the photoconductor having a potential of _VH over the entire peripheral surface of the photoconductor drum 10 where no image of the first color is formed, a latent image similar to that of the first color is formed and development is performed. is carried out, 1 again part for developing image to the portion where there is the color, the latent image of V _M 'by the charge possessed by the shading of the toner itself by the toner adhering the first color is formed, V
Developing in response to the potential difference between the _DC and V _M 'is performed. In the overlapping portion of the first color image and the second color image, development of the first color is performed by V
_When the latent image of _L is formed, the balance between the first color and the second color is lost, so that the exposure amount of the first color is reduced and V _H > V _M >
In some cases, the intermediate potential may be V _L.

For the third color cyan and the fourth color black, the same image forming process as that for the second color is performed.
A visual image of four colors is formed on the zero circumference.

On the other hand, the half moon roller 16
One sheet of recording paper (image support) P carried out via the printer is temporarily stopped, and is fed to the transfer area by the rotation of the sheet feed roller 17 when the timing of transfer is adjusted.

In the transfer area, a transfer roller 18 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing, and the fed image support P is sandwiched to transfer the multicolor image at once. Is done.

Next, the image support P is almost neutralized by the separation brush 19 brought into a pressure contact state at the same time, is separated from the peripheral surface of the photosensitive drum 10, and is conveyed to the fixing device 20, where the heat roller (upper roller) 201 and the pressure roller (Lower roller) 20
After the toner is welded by heating and pressurizing of 2, the toner is discharged to the outside of the apparatus via the discharge roller 21. Note that the transfer roller 18 and the separation brush 19 are retracted and separated from the peripheral surface of the photosensitive drum 10 after passing through the image support P to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 10 from which the image support P has been separated removes and cleans the residual toner by pressing the blade 221 of the cleaning device 22 and receives the charge by the PCL 11 and the charge by the charger 12 again to form the next image. Enter the formation process. The blade 221 is moved immediately after cleaning the surface of the photoconductor,
Evacuate from the surrounding surface.

[0068]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

(1) Preparation of Binder Resin Toluene is put into a separable flask equipped with a thermometer, a stirrer, a nitrogen gas inlet tube, and a falling condenser, and nitrogen gas is introduced from the gas inlet tube to clean the inside. After the atmosphere was activated, the mixture was heated in an oil bath and heated to the reflux temperature of toluene. Next, the amount of each monomer shown in Table 1 (parts by weight) was added to 100 parts by weight of toluene, and a mixture in which 4 parts by weight of di-t-butyl peroxide as a polymerization initiator was dissolved was added dropwise. Solution polymerization was carried out while obtaining a high molecular weight polymer.

Next, in a flask having the high molecular weight polymer solution, each monomer and additive containing a crosslinkable component shown in Table 1 were added in an amount shown in Table 1 to 1,000 parts by weight of toluene, and polymerization was started. Solution polymerization was carried out while dropwise adding a mixture in which 40 parts by weight of di-t-butyl peroxide as an agent was dissolved. After completion of the dropwise addition, the mixture was aged for 5 hours while stirring the reaction system at a temperature at which toluene was boiling to obtain a low molecular weight polymer.

Next, zinc oxide was added as a metal oxide in the amount shown in Table 1 or not, and the reaction was carried out at reflux temperature for 2 hours while stirring the reaction system. Thereafter, toluene was removed under reduced pressure while gradually raising the temperature of the reaction system to 180 ° C., and further cooled, and the resulting solid was pulverized to obtain a crosslinked vinyl polymer.

In the above, the monomers used for preparing the high molecular weight polymer are styrene (St), methyl methacrylate (MMA) and butyl acrylate (BA), and the monomers used for preparing the low molecular weight polymer are styrene. (St), methyl methacrylate (MMA), butyl acrylate (BA) and methacrylic acid (MAA), and the metal oxide is zinc oxide (ZnO).

[0073]

[Table 1]

(2) Production of Toner 100 parts by weight of the crosslinked vinyl polymer, 8 parts by weight of the coloring agent shown in Table 2, 100 parts by weight of the resin, and 5 parts by weight of polypropylene were mixed with a Henschel mixer. Then, the mixture was melt-kneaded with a twin-screw extruder, cooled and solidified, and crushed, and then, a colored particle having a volume average particle size of 8.5 μm was obtained using a particle collision type fine powder crusher and an airflow classifier. . For 100 parts by weight of the colored particles, 0.5 parts by weight of hydrophobic silica "R-972" (manufactured by Nippon Aerosil Co., Ltd.) and 1.0 parts by weight of hydrophobic titania "T-805" (manufactured by Nippon Aerosil Co., Ltd.) And toners of the present invention (T1 and T2) and comparative toners (H1 to H4) by mixing with a Henschel mixer.

Here, comparative toners H1, H2 and H4
Does not contain a crosslinkable component consisting of a specific bifunctional acrylic compound or bifunctional methacryl compound.

[0076]

[Table 2]

(3) Preparation of carrier 40 g of copolymer fine particles of styrene / methyl methacrylate = 4/6, specific gravity 5.0, weight average diameter 45 μm, 100
1960 g of Cu-Zn ferrite particles having a saturation magnetization of 62 emu / g when an external magnetic field of 0 Oe is applied
Was charged into a high-speed stirring type mixer and mixed at a product temperature of 30 ° C. for 15 minutes, and then the product temperature was set at 105 ° C. and the mechanical impact force was 3
It was repeatedly applied for 0 minutes and cooled to prepare a carrier.

(4) Preparation of Developer 558 g of the above carrier and 42 g of each toner were mixed for 20 minutes using a V-type mixer to prepare a developer for a real test.

(5) Evaluation of Characteristics <Evaluation Apparatus and Evaluation Conditions> In the embodiment, a color copying machine Konica 902 manufactured by Konica Corporation was used as an image forming apparatus.
8 using a modified machine. The main remodeling points and main conditions of the device are as follows.

[0080] photosensitive member surface potential = -550 V DC bias = -250 V AC bias _{= V pp: -50~-450V Dsd} ( Distance developing sleeve and the photosensitive member) = Normal heat roller fixing device used as 300μm fixing device It was used. That is, a hollow aluminum roller having a diameter of 30 mm and a thickness of 5 mm coated with PFA is used as the upper roller, and has a heat source for heating at the center.

<Image Forming Test> In the test, a reflection image (image on paper) and a transmission image (OHP image) are formed on paper and OHP by the above-described image forming method using the developer using the yellow toner of the present invention. The evaluation was performed by the following method. Note that the toner adhesion amount is 0.7 ± 0.
The evaluation was performed in the range of 05 (mg / cm ² ).

Hue change: Macbeth Color Eye 7000
(Macbeth) and the hue and O of the reflected image on paper
The hue difference of the transmission image of the HP image was measured and compared. A smaller hue change absolute value means a smaller hue change.

Light resistance: After performing an exposure test for 7 days using “Xenon Long Life Weather Meter” (Xenon Arc Lamp, 70000 lux, 44.0 ° C.) manufactured by Suga Test Instruments Co., Ltd., Macbeth Color Eye 7000 (Macbeth Co., Ltd.) The color difference from the image before the test was measured according to the above method, and the comparison was performed. The smaller the color difference, the better the light resistance.

<Evaluation Results> The above results are shown in Table 3.

[0085]

[Table 3]

As is evident from Table 3, it is clear that the use of the color toner of the present invention can provide an OHP image having high light resistance and little change in hue. On the other hand, it can be seen that the comparative toner cannot simultaneously satisfy the light fastness and the hue change of the OHP image.

[0087]

According to the present invention, a yellow toner for developing an electrostatic image with excellent transparency of an OHP image, a small change in the hue of a transmitted color, and excellent light fastness even under oilless fixing is provided. An image forming method using the same can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a color printer for explaining an image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor drum (image carrier) 11 PCL (pre-charging static eliminator) 12 scorotron charger 13 image exposure unit 14, 14Y, 14M, 14C, 14K developing unit 15 paper feed cassette 18 transfer roller (transfer unit) 19 separation brush (Separation unit) 20 Fixing device 22 Cleaning device P Recording paper (image support)

Claims (3)

[Claims] 1. An electrostatic image developer containing, as a binder resin, a vinyl polymer synthesized using at least one of a monomer represented by the following general formula (a) and a monomer represented by the following general formula (b): A color toner for developing an electrostatic image, comprising at least the following compound (c) as a coloring agent. Embedded image In the general formula (a), R _{1 to} R ₈ each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or an aryl group;
₉ and R ₁₀ each represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, and X represents 1 to 1 carbon atom.
6 represents a chain alkylene group, a polymethylene group, a chain or cyclic alkylidene group having 2 to 6 carbon atoms, or a simple bond; Y represents a chain alkylene group having 1 to 6 carbon atoms; Group, having 2 to 1 carbon atoms
0 chain or cyclic alkylidene group, aryl-substituted alkylidene group, sulfonyl group, sulfide group or-
O- or a mere bond. n is 1 to 5
Represents an integer. In the general formula (b), R ₁₁ and R ₁₂ are each:
Represents a hydrogen atom or a chain or cyclic alkyl group having 1 to 6 carbon atoms, and R ₁₃ and R ₁₄ are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or Represents an aryl group (R ₁₃ and R ₁₄
May or may not be the same, and furthermore, R ₁₃ and R ₁₄
May combine with each other to form a ring). m is 3 to 20
Represents an integer. 2. A developer prepared by mixing the color toner for developing an electrostatic image according to claim 1 with a carrier. 3. An image forming method for forming a color image by charging, exposing and developing using the color toner for developing an electrostatic image according to claim 1.