JP2003270837A - Electrostatic image developing toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic latent image developing toner which does not cause such problems as an increase of toner consumption, fusion bonding of a toner to a developing roller and a developing blade, etc., wear of a developing roller by toner and lowering of image density of an intermediate color tone and stably gives good developed image quality over a prolonged period of time and to provide an image forming method. <P>SOLUTION: The electrostatic image developing toner contains toner particles having a sphericity of ≥0.75 and comprising a colorant and a binder resin based on a polyester resin comprising at least a propylene oxide adduct of bisphenol A and fumaric acid as monomer components and having a number average molecular weight (Mn) of 3,000-7,000, a weight average molecular weight (Mw) of 21,000-27,000, an Mw to Mn ratio of 3-9, a peak molecular weight of 8,000-12,000 in its molecular weight distribution and an acid value of ≤12. The image forming method includes a step for developing an electrostatic latent image formed on an electrostatic latent image carrier with such a toner. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner used for developing an electrostatic latent image formed by electrophotography and the like, and an image forming method using the toner.

[0002]

2. Description of the Related Art In an image forming system using an electrophotographic technique, an electrostatic latent image is generally formed on a photoconductor containing a photoconductive material, and then the latent image is developed with a developer called toner, and then the latent image is developed. The toner image is transferred to a recording material such as paper and fixed. As the toner, a toner in which a colorant (pigment or dye) is dispersed in a thermoplastic resin binder resin and then pulverized to a desired particle size is used.

By the way, in recent years, the definition of copied / printed images has become higher in definition, and the copying / printing speed has become faster. Accordingly, there has been a strong demand for improvement of image stability in continuous printing and the like. Therefore, various attempts have been made to stabilize the image, such as improvement of the developing method, selection of members used in the developing machine, and improvement of toner characteristics. In particular, it is known that toner characteristics greatly affect the improvement and maintenance of image quality, and many methods have been tried to improve this.

[0004] For example, selection of an additive to be added to the binder resin and optimization of the addition amount are typical. That is, in this method, it is general practice to add a charge control agent to the toner, for example, in order to control the chargeability thereof, or to mix a release agent such as wax in order to prevent an offset phenomenon at the time of fixing. Therefore, it is intended to improve the toner characteristics and stabilize the image by properly selecting the kind and the addition amount of these additives.

[0005]

However, in such a conventional method, the continuous printing causes a gradual increase in the amount of toner consumed (which is considered to occur due to insufficient compatibility between the binder resin and the additive). The toner particles and wax separated from the toner particles are fused to the developing roller and the developing blade, and streaks and spots appear on the image.
There is a problem that the developing roller wears and the image changes, especially the image density in the intermediate tone decreases, and a toner giving excellent image stability has not been obtained yet.

As described above, the image characteristics and the image stability are affected not only by the toner characteristics but also by the members used in the developing machine. That is, image characteristics such as image density and background fog in which toner is printed on the non-printed portion are greatly influenced by the layer thickness of the toner layer formed on the developing roller. The layer thickness of the toner layer is affected by various factors such as the toner supply amount to the developing roller, the material of the developing roller and the developing blade, as well as the toner characteristics. Therefore, in order to control the toner layer thickness and improve the image characteristics, it is necessary to consider both the toner and the developing device.

The present invention has been made in view of the above conventional circumstances, and increases the toner consumption amount, the fusion of the toner to the developing roller and the developing blade, the abrasion of the developing roller due to the toner, and the image of the intermediate tone. An object of the present invention is to provide a toner for developing an electrostatic latent image and an image forming method which can stably provide good development image quality over a long period of time without causing a problem such as a decrease in density.

[0008]

In order to achieve the above object, the invention according to claim 1 has a number average molecular weight (Mn) of 3000 to 7000, which comprises at least a bisphenol A propylene oxide adduct and fumaric acid as monomer components. , Weight average molecular weight (Mw) 21000 to 27,000, weight average molecular weight (M
w) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8000 to 12000, binder resin mainly composed of polyester resin having acid value of 12 or less, and colorant, and having sphericity A toner for developing an electrostatic latent image, which comprises toner particles having a particle size of 0.75 or more.

According to a second aspect of the invention, in the electrostatic latent image developing toner according to the first aspect, the sphericity of the toner particles is 0.
The toner for electrostatic latent image development is characterized in that it is 75 to 1.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the electrostatic latent image developing toner described above, the toner particles are
Further, a non-oxidizing polypropylene wax having a weight average molecular weight (Mw) of 2000 to 5000, an ester wax having an acid value of 10 or less, a carnauba wax having an acid value of 10 or less, and a weight average molecular weight (Mw) of 600 to 1500. An electrostatic image developing toner comprising at least one selected from the group of paraffin wax.

In order to achieve the above object, the invention according to claim 4 has a number average molecular weight (Mn) of 3000 to 7,000 and a weight average molecular weight of at least bisphenol A propylene oxide adduct and fumaric acid as monomer components. (Mw) 21,000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8,000 to 12000, binder resin mainly composed of polyester resin having an acid value of 12 or less, and coloring An electrostatic latent image formed on a latent electrostatic image bearing member is developed with an electrostatic latent image developing toner containing a toner particle having a sphericity of 0.75 or more. An image forming method characterized by including steps.

According to a fifth aspect of the present invention, in the image forming method according to the fourth aspect, the developing is performed by a developing roller having at least an outermost layer made of conductive rubber, a developing blade mainly made of metal, and a toner on the developing roller. And a toner supply roller for supplying toner to the developing roller and a toner control blade disposed near the toner supplying roller for controlling the amount of toner supplied to the developing roller together with the toner supplying roller. Image forming method.

In the electrostatic latent image developing toner and the image forming method having the above-mentioned constitution, the amount of toner consumed for development is stable even in long-term continuous printing, and the toner for the developing roller and the developing blade in the developing machine is stable. No problem such as fusing and abrasion of the developing roller due to toner occurs, and further, a good image can be stably obtained without lowering the density of the intermediate tone.

Particularly, when the sphericity of the toner particles is 0.75 to 1, or the toner particles are further a non-oxidizing polypropylene wax having a weight average molecular weight (Mw) of 2000 to 5000 and an acid value of 10 or less. Ester wax, acid value
When the carnauba wax of 10 or less and at least one kind selected from the group of paraffin waxes having a weight average molecular weight (Mw) of 600 to 1500 are contained, in the image forming method, development is performed at least in the outermost layer from a conductive rubber. When the one-component developing machine equipped with the developing roller is used, the above effect becomes more remarkable.

In the present specification, the number average molecular weight, the weight average molecular weight and the peak molecular weight are values calculated by styrene conversion using the GPC (gel permeation chromatography) method, and the acid value is 10 mg of a sample in 50 ml of toluene.
It is a value calculated from the consumption amount by dissolving in, and titrating with a previously evaluated N / 10 potassium hydroxide / alcohol solution using a mixed indicator of 0.1% bromthymol blue and phenol red. The sphericity is a value obtained by dividing the shortest diameter of toner particles by the longest diameter, and is a value measured by a multi-image analyzer manufactured by Beckman Coulter. The multi-image analyzer measures the number of particles and the particle size distribution based on the electric resistance method, and at the same time, uses a signal generated at the moment when the particles pass through the pores as a timing to photograph a particle image.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The toner for developing an electrostatic latent image of the present invention contains at least a bisphenol A propylene oxide adduct and fumaric acid as monomer components, and has a number average molecular weight (Mn).
3000 to 7,000, weight average molecular weight (Mw) 21000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8,000 to 12000, mainly polyester resin with an acid value of 12 or less And a binder resin,
And toner particles containing a colorant.

The sphericity of the toner particles is 0.75 or more,
It is more preferably 0.75 to 1. When the sphericity of the toner particles is less than 0.75, it becomes difficult to maintain the image density, especially the image density of the intermediate tone.

In the present invention, as the binder resin,
It is essential to use the specific polyester resin as described above, and if the number average molecular weight (Mn) or the weight average molecular weight (Mw) is smaller than the above range, the particles are separated from each other in the spheroidizing step of the toner particles described later. As a result of agglomeration and adhesion of toner particles to the device, the required sphericity cannot be obtained. Conversely, the number average molecular weight (Mn) or the weight average molecular weight (M
If w) is larger than the above range, the colorant and other additives are not well dispersed, and the charging characteristics of the resulting toner deteriorate. In addition, weight average molecular weight (Mw) / number average molecular weight (M
If n) is out of the above range or the peak molecular weight in the molecular weight distribution is out of the above range, it causes a high temperature / low temperature offset at the time of fixing. Further, if the acid value is larger than the above range, fogging or the like occurs at high temperature and high humidity. In the present invention, particularly, the number average molecular weight (Mn) 4000 to 5000, the weight average molecular weight (Mw) 23000 to 25000, and the weight average molecular weight (M
w) / number average molecular weight (Mn) 4.6 to 6.25, peak molecular weight in the molecular weight distribution of 9000 to 10000, and acid value of 9 to 11.5 are preferably used polyester resins.

Specific examples of the polyester resin used in the present invention include polyoxypropylene (2,
2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl)
Polycondensation of fumaric acid with one or more of propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and the like, and further with these components, fumaric acid and radical polymerization Examples thereof include those obtained by adding a reactive monomer component such as styrene or a derivative thereof and performing both polymerization reactions in parallel in the same container.

A toner using such a polyester resin as a binder resin is suitable as a full-color toner because it has excellent heat-melting property and transparency, and also has excellent dispersibility of additives. These effects are fully expressed. Further, the deterioration in the developing machine is small, and the image stability in long-term continuous printing can be improved.

In the present invention, as the binder resin,
One or more known thermoplastic synthetic resins and natural resins conventionally used as binder resins for toner may be used in combination with the above polyester-based resin. Examples of such resin include styrene resin, acrylic resin, styrene-acrylic resin, olefin resin, diene resin, polyester resin, polyamide resin, epoxy resin, silicone resin, phenol resin. , Petroleum resin, urethane resin and the like.

Next, as the colorant used in the present invention, known pigments and dyes can be used,
For example, carbon black, phthalocyanine blue, azo lake pigment, quinacridone pigment and the like can be mentioned. The content of the colorant is usually 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the binder resin.

The toner particles of the present invention ensure the releasability of the recording material from the fixing member at the time of toner fixing, and
(A) Weight average molecular weight (Mw) of 2000 to 5000 in order to prevent fusion of the toner to the developing roller and the developing blade for forming the toner layer thereon and abrasion of the developing roller.
Non-oxidizing polypropylene wax, (b) ester wax having an acid value of 10 or less, (c) carnauba wax having an acid value of 10 or less, and (d) weight average molecular weight (Mw)
It is preferable to contain at least one selected from the group of paraffin waxes of 600 to 1500. The weight average molecular weight of the non-oxidized polypropylene wax (a) (M
When w) is less than 2000, it becomes compatible with the binder resin and deteriorates the resin properties, so that a good image cannot be obtained. On the other hand, when the weight average molecular weight (Mw) exceeds 5,000, the dispersibility in the binder resin becomes poor and the above effects cannot be sufficiently obtained. Further, when the acid value of the ester wax of (b) and the carnauba wax of (c) exceeds 10, fogging occurs in the image, and the effect is particularly large at high temperature and high humidity. Further, if the weight average molecular weight (Mw) of the paraffin wax of (d) is less than 600, the paraffin wax is compatible with the binder resin to deteriorate the resin properties and a good image cannot be obtained. On the other hand, when the weight average molecular weight (Mw) exceeds 1500, the dispersibility in the binder resin becomes poor and the above effects cannot be sufficiently obtained. The content of these waxes is usually 0.05 to 10 with respect to 100 parts by weight of the binder resin.
Parts by weight, preferably 0.5-5 parts by weight.

In the present invention, one or more known waxes conventionally used as a releasing agent for toner may be used in combination within a range that does not impair the effects of the present invention. Examples of such waxes include polyethylene wax, rice wax, and Fischer-Tropsch wax.

In addition, in the toner for developing an electrostatic latent image of the present invention, a charge control agent for controlling the charging property of the toner, a resin for dispersion for enhancing the dispersibility of the colorant, and a flow of the toner, if necessary. You may make it contain a fluidizing agent etc. for improving a property. As the charge control agent, boron benzoyl complex, phenol condensation type calixarene, zinc salicylate metal complex, chromium salicylate metal complex, aluminum salicylate metal complex, etc. Can be used. The content of this charge control agent is usually 0.01 to 20 parts by weight, preferably 100 parts by weight of the binder resin, preferably
0.5 to 5 parts by weight.

In the toner particles of the present invention, the above-mentioned binder resin, colorant, and other additives to be added as required are mixed by a mixer such as a Henschel mixer or a ball mill, and then the mixture is heated on a roll. Nida,
It is melt-kneaded by a kneader such as an extruder, cooled and solidified, then pulverized and classified to obtain toner base particles having a particle diameter of several μm to several tens of μm, and the obtained toner base particles are heat-treated. It can be manufactured by spheroidizing to a desired sphericity.

For the heat treatment for spheroidizing, it is preferable to use an apparatus in which the toner particles are momentarily brought into contact with a hot air stream of high temperature and the surface thereof is melted to be spheroidized. Examples of such a heat treatment device include a surfusing system manufactured by Nippon Pneumatic Co., Ltd. In order to obtain toner particles having a sphericity of 0.75 or more using such an apparatus, it is preferable to control the hot air temperature in the range of 80 to 500 ° C, and more preferably 150 to 400 ° C. If the temperature is too high, the toner particles will fuse together, and if too low, the spheroidization will not proceed.

In the present invention, a metal such as alumina, silica, zinc oxide, titanium oxide or iron oxide is added to the surface of the toner particles thus obtained for the purpose of enhancing the fluidity and further controlling the charging property. One or more kinds of oxide fine particles may be externally added.

Next, an image forming method of the present invention using such an electrostatic latent image developing toner will be described. The image forming apparatus used in the image forming method of the present invention is not particularly limited as long as it uses a developing method using a one-component non-magnetic toner, and particularly, an image as shown in FIG. 1 or FIG. It is preferable to use a forming device.

That is, FIGS. 1 and 2 are schematic configuration diagrams showing an example of an image forming apparatus suitable for the image forming method of the present invention. FIG. 1 shows an image provided with a one-component non-contact developing machine. An example of the image forming apparatus, and FIG. 2 is an example of an image forming apparatus including a one-component contact type developing machine. It should be noted that in these figures, common parts are denoted by the same reference numerals, and redundant description is omitted. Further, in these examples, a photoconductor is used as the electrostatic latent image carrier.

In these figures, 10 is a photosensitive drum on the surface of which an electrostatic latent image is formed.
0 is driven to rotate clockwise in the figure.

Further, reference numeral 20 is a developing machine for developing the electrostatic latent image formed on the photosensitive drum 10, and
On the developing roller 21 and at least the outermost layer of which is a conductor layer, which are arranged to face each other in a non-contact (FIG. 1) or contact (FIG. 2) state and are driven to rotate counterclockwise in the figure. And a developing blade 22 for forming a toner layer. The developing blade 22 is in contact with the developing roller 21 at a flat portion near the center from the free end, but the free end may be lightly pressed into contact with the developing roller 21. In the present invention, it is preferable that at least the outermost layer is made of conductive rubber as the developing roller 21, and the developing blade 22 is made of metal or a part thereof (a contact portion with the developing roller 21). )
It is preferable to use a resin or rubber adhered only to. A developing bias voltage is applied to the conductor layer on the surface of the developing roller 21.

The developing machine 20 is also provided with a toner filling section 23. In the toner filling section 23, a stirring device 24 for stirring the toner, a toner supply roller 25 for supplying the toner onto the developing roller 11 by rotation, A toner control blade 26 that controls the amount of toner supplied to the developing roller 21 is provided.

The toner filled in the toner filling section 23 is
The toner supply roller 25 and the toner control blade 26 control the amount of the toner to be supplied to the developing roller 21, and the developing blade 22 regulates the amount of the toner, and the toner passes through the contact portion between the developing blade 22 and the developing roller 21. Is charged and the developing roller 21
A charged toner layer having a uniform thickness is formed on the surface of the. The toner layer formed on the surface of the developing roller 11 develops the electrostatic latent image formed on the photosensitive drum 10.

1 and 2, further, 30 is
An intermediate transfer member 40, which is in contact with the photosensitive drum 10 and is driven to rotate in the opposite direction in synchronism with the photosensitive drum 10, is a fixing device for fixing the toner image transferred from the intermediate transfer member 30 onto a recording sheet (not shown). is there.

The toner image formed on the photosensitive drum 10 by being developed by the developing device 20 is transferred onto a recording paper (not shown) through the intermediate transfer member 30 and fixed by the fixing device 40.

Although not shown, the image forming apparatus is provided with a device for forming an electrostatic image on the photosensitive drum 10, a mechanism for supplying and conveying recording paper, and the like. ing.

In the above-mentioned image forming method using the toner for electrostatic latent image development of the present invention, the amount of toner used does not increase even during long-term continuous use, and the toner is fused to the developing blade or developing roller. Wear and abrasion of the developing roller are also suppressed. Further, the reduction of the image density of the intermediate tone is also prevented. Thereby, it is possible to stably obtain a high quality image for a long period of time.

Although the above-mentioned image forming apparatus is of a type in which the toner image is transferred onto the recording paper via the intermediate transfer body, it may be of a type in which the toner image is directly transferred without passing through the intermediate transfer body. In addition, the developing machine configured as above is
The image forming apparatus provided with the base is useful as an apparatus for forming a full-color image using the toner for developing an electrostatic latent image of the present invention.

[0040]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. In the following description, "part"
Indicates "parts by weight".

Example Polyester resin obtained by polycondensing bisphenol A propylene oxide adduct and fumaric acid (number average molecular weight Mn4427, weight average molecular weight Mw24349, weight average molecular weight Mw / number average molecular weight Mn5.5, in molecular weight distribution Peak molecular weight of 9963, acid value of 9.9) 100 parts, magenta pigment Pigment Red 57: 1 3 parts, polypropylene wax (weight average molecular weight Mw 3000, softening point 145 ° C) 3 parts, boron benzyl acid complex 1 part as a charge control agent. After adding and thoroughly mixing with a Henschel mixer, they were melt-kneaded with a twin-screw extrusion kneader. The obtained kneaded product was roughly pulverized with a speed mill, the pulverized product was finely pulverized with a jet pulverizer, and then classified with a wind power classifier to obtain toner particles having a volume average particle size of 10 μm. Then, the toner particles were heated to 400 by a heat treatment device SFS-03 (trade name) manufactured by Nippon Pneumatic Co., Ltd.
Heat treatment was performed at a temperature of ° C. The sphericity of the obtained toner particles was 0.798. To 100 parts of this toner particle, silica powder
1.0 part was added and mixed in a Henschel mixer to produce magenta toner particles.

Instead of magenta pigment, yellow pigment Pigment Yellow 12 and cyan pigment Pigment Blue 15
Particles of yellow toner, cyan toner and black toner were obtained in the same manner as above except that and carbon black were used. The sphericity of each toner particle after the heat treatment was 0.801 for yellow toner particles, 0.790 for cyan toner particles, and 0.806 for black toner particles.

The above-mentioned toner particles of four colors are converted into a one-component non-contact type developing device having the structure shown in FIG. 1 (developing roller: aluminum roller coated with conductive silicone rubber, developing blade: blade made of phosphor bronze, photoconductor). The separation distance between the drum and the developing roller is 150 μm) Each developing machine of the full-color image forming apparatus equipped with four units is filled respectively, and the negatively charged electrostatic image for each color formed on the photosensitive drum is sequentially developed. A full-color toner image was formed on the intermediate transfer member, and this image was transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured by using a color difference meter. As a result, magenta was 0.59, yellow was 0.87, cyan was 0.45, and black was 0.74. Was obtained. Further, when a full-color image having a printing rate of 5% was continuously printed while appropriately replenishing the recording paper and toner, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. Paper
When the total consumption of each toner per sheet was examined, it was 210 mg in the initial stage and 215 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. In addition, when we printed a halftone with a printing rate of 50% to check the density of the intermediate tone, the image density was 0.73 for magenta, 0.70 for yellow, and 0.80 for cyan.
A black density of 0.74 provided sufficient density. After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

A full-color image forming apparatus having four one-component contact type developing devices (developing roller: aluminum roller coated with conductive silicone rubber, developing blade: blade made of phosphor bronze) having the structure shown in FIG. The same effects as in Example 1 were also observed when full-color images were printed by filling each of the developing machines with four color toner particles prepared in the same manner as in Example 1.

That is, when the background stain (fogging level) of the obtained image was measured using a color difference meter, magenta
0.50, yellow 0.53, cyan 0.57, black 0.53
, A clear image with very little fog was obtained. Further, when a full-color image having a printing rate of 5% was continuously printed while appropriately replenishing the recording paper and toner, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. Examining the total consumption of each toner per sheet of paper, 210 mg in the initial stage, 215 mg after continuous printing of 10,000 sheets,
The toner consumption was stable. Moreover, when a halftone with a printing rate of 50% was printed to check the density of the intermediate tone, the image density was 0.79 for magenta, 0.77 for yellow, 0.77 for cyan, and 0.71 for black, and sufficient density was obtained. .
After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

On the other hand, in the image forming apparatus having the same structure as that used in the above embodiment except that the developing roller is an aluminum roller coated with a phenol resin containing carbon fine particles and conductive graphite, the above embodiment is used. 1
When a full-color image is printed by applying four color toner particles prepared in the same manner as above, the image background stain (fogging level) measured by a color difference meter is 0.52% for magenta, 0.55% for yellow, and 0.55% for cyan. Is 0.53%, black is 0.57, and a clear image is obtained. Also, the result of printing halftone with a printing rate of 50% to check the density of intermediate tones shows that the image density is magenta 0.73, yellow 0.75, and cyan. Was 0.77 and black was 0.74, which was a sufficient density. However,
In continuous printing of color images with a printing rate of 5% while replenishing the recording paper and toner appropriately, streaks start to appear on the image from about 5000 sheets, and after continuous printing of 10,000 sheets, the surface of the developing blade and developing roller is visually inspected. As a result of observation at
It was confirmed that the toner adhered to the developing blade. The total consumption of each toner per sheet was stable at 220 mg in the initial stage and 211 mg after continuous printing of 10,000 sheets.

Example 2 Four color toner particles of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 1 except that ester wax (acid value 4.5) was used in place of polypropylene wax. did. The sphericity of each toner particle after heat treatment is
0.800, yellow toner particles were 0.809, cyan toner particles were 0.790, and black toner particles were 0.799. The obtained four-color toner particles are filled in each developing machine of a full-color image forming apparatus equipped with four one-component non-contact type developing machines as in the case of Example 1, and formed on the photosensitive drum. The formed negatively charged electrostatic images for each color were sequentially developed to form a full-color toner image on the intermediate transfer body, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured by using a color difference meter. As a result, magenta was 0.77, yellow was 0.60, cyan was 0.79, and black was 0.54. Was obtained. Further, when a full-color image having a printing rate of 5% was continuously printed while appropriately replenishing the recording paper and toner, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. Paper
When the total consumption of each toner per sheet was examined, it was 224 mg in the initial stage and 230 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. In addition, when we printed a halftone with a print rate of 50% to check the density of the intermediate tone, the image density was 0.69 for magenta, 0.72 for yellow, and 0.75 for cyan.
Black was 0.70, and a sufficient density was obtained. After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Example 3 Toner particles of four colors of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 1 except that carnauba wax (acid value 6.6) was used in place of polypropylene wax. did. The sphericity of each toner particle after the heat treatment was measured with an image analyzer manufactured by Beckman Coulter Inc., and was 0.803 for magenta toner particles, 0.799 for yellow toner particles, 0.801 for cyan toner particles, and 0.801 for black toner particles. there were.

The obtained toner particles of four colors were filled in each developing machine of a full-color image forming apparatus equipped with four one-component non-contact type developing machines as in the case of Example 1, and the photosensitive drums were charged. The negatively charged electrostatic image for each color formed above was sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured using a color difference meter. As a result, magenta was 0.58, yellow was 0.54, cyan was 0.60, and black was 0.49. Was obtained. Further, when a full-color image having a printing rate of 5% was continuously printed while appropriately replenishing the recording paper and toner, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. Paper
When the total consumption of each toner per sheet was examined, it was 216 mg in the initial stage and 220 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. In addition, when a halftone with a print rate of 50% was printed to check the density of intermediate tones, the image density was 0.77 for magenta, 0.75 for yellow, and 0.76 for cyan.
A black density of 0.72 provided sufficient density. After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Example 4 Toner particles of four colors of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 1 except that paraffin wax (weight average molecular weight Mw1060) was used in place of polypropylene wax. Prepared. The sphericity of each toner particle after the heat treatment was measured with an image analyzer manufactured by Beckman Coulter Inc., and was 0.808 for magenta toner particles, 0.796 for yellow toner particles, 0.799 for cyan toner particles, and 0.792 for black toner particles. there were.

The obtained toner particles of four colors were filled in respective developing machines of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to those in Example 1, and the photosensitive drums were charged. The negatively charged electrostatic image for each color formed above was sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured by using a color difference meter. As a result, magenta was 0.58, yellow was 0.57, cyan was 0.68, and black was 0.63. Was obtained. Further, when a full-color image having a printing rate of 5% was continuously printed while appropriately replenishing the recording paper and toner, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. Paper
When the total consumption of each toner per sheet was examined, it was 206 mg in the initial stage and 209 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. In addition, when we printed a halftone with a printing rate of 50% to check the density of the intermediate tones, the image density was 0.73 for magenta, 0.69 for yellow, and 0.78 for cyan.
A black density of 0.72 provided sufficient density. After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Comparative Example 1 As a binder resin, a polyester resin obtained by polycondensing a bisphenol A propylene oxide adduct and phthalic acid (number average molecular weight Mn3317, weight average molecular weight M
w123166, weight average molecular weight Mw / number average molecular weight Mn 37.
1, magenta toner in the same manner as in Example 1 except that the peak molecular weight in the molecular weight distribution was 8999 and the acid value was 0.5).
For yellow toner, cyan toner and black toner
Four color toner particles were prepared. The sphericity of each toner particle after the heat treatment is 0.806 for magenta toner particles, 0.811 for yellow toner particles, and 0.807 for cyan toner particles.
The black toner particles were 0.803.

The obtained toner particles of four colors were filled in respective developing machines of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to those in Example 1, and the photosensitive drums were charged. The electrostatic images of the respective colors formed above were sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured using a color difference meter. As a result, magenta was 0.58, yellow was 0.55, cyan was 0.55, and black was 0.53. Was obtained. However,
Furthermore, the printing rate is 5 while replenishing the recording paper and toner appropriately.
% After continuously printing 10000 full-color images, the background stain (fogging level) of the image was measured using a color difference meter. Magenta was 3.55, yellow was 2.89, and cyan was 4.2.
8, black was 4.50, and the fog on the recording paper increased.
The total consumption of each toner per sheet is 220 mg in the initial stage.
However, it increased to 415 mg after continuous printing of 10,000 sheets. On the other hand, when printing halftone with a printing rate of 50% and measuring the image density, magenta was 0.77, yellow was 0.80,
Cyan was 0.73 and black was 0.75, which were sufficient densities. After continuous printing of 10,000 sheets, the developing blade and the roller surface of the developing roller were visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Comparative Example 2 Four color toner particles of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 1 except that the heat treatment step was not performed on the toner particles. The sphericity of each toner particle after the heat treatment was 0.700 for magenta toner particles, 0.699 for yellow toner particles, 0.695 for cyan toner particles, and 0.697 for black toner particles.

The obtained four-color toner particles are filled in each developing machine of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to those in Example 1, and the photoreceptor drum is charged. The electrostatic images of the respective colors formed above were sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured using a color difference meter. As a result, magenta was 0.56, yellow was 0.53, cyan was 0.58, black was 0.55, and a clear image with very little fog was obtained. Was obtained. Further, when a full-color image with a printing rate of 5% was continuously printed on 10,000 sheets while replenishing the recording paper and toner appropriately, an image comparable to the initial one was obtained even after continuous printing of 10,000 sheets. The total consumption of each toner per sheet is 2
17 mg, 222 mg after continuous printing on 10,000 sheets, and the toner consumption was stable. However, when the halftone with a print rate of 50% was printed and the image density was measured, magenta was 0.44,
Yellow was 0.46, cyan was 0.47, and black was 0.41, which was not a sufficient density. On the other hand, after continuous printing of 10,000 sheets, the roller surface of the developing blade and the developing roller was visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Comparative Example 3 Toner particles of four colors of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 2 except that the heat treatment step was not performed on the toner particles. The sphericity of each toner particle was 0.669 for magenta toner particles, 0.680 for yellow toner particles, 0.672 for cyan toner particles, and 0.672 for black toner particles.

The obtained toner particles of four colors were filled in respective developing machines of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to those in Example 1, and the photosensitive drums were charged. The electrostatic images of the respective colors formed above were sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured using a color difference meter. As a result, magenta was 0.47, yellow was 0.45, cyan was 0.54, and black was 0.51. Was obtained. Further, when replenishing the recording paper and toner appropriately, a full-color image with a printing rate of 5% was continuously printed on 10,000 sheets. Even after continuous printing of 10,000 sheets, an image comparable to the initial one was obtained (10000). Image background stain (fog level) after continuous printing on one sheet: magenta 0.50, yellow 0.48, cyan 0.55, black 0.53). The total consumption of each toner per sheet was 209 mg in the initial stage and 213 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. However, when a halftone with a print ratio of 50% was printed and the image density was measured, the density was 0.39 for magenta, 0.45 for yellow, 0.43 for cyan, and 0.48 for black, which were not sufficient. On the other hand, after continuous printing of 10,000 sheets, the roller surface of the developing blade and the developing roller was visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Comparative Example 4 Toner particles of four colors of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 3 except that the heat treatment step was not performed on the toner particles. The sphericity of each toner particle was 0.697 for magenta toner particles, 0.698 for yellow toner particles, 0.691 for cyan toner particles, and 0.689 for black toner particles.

The obtained toner particles of four colors were filled in respective developing machines of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to those in Example 1, and the photosensitive drums were charged. The electrostatic images of the respective colors formed above were sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured using a color difference meter. As a result, magenta was 0.56, yellow was 0.55, cyan was 0.60, and black was 0.52. Was obtained. Further, when replenishing the recording paper and toner appropriately, a full-color image with a printing rate of 5% was continuously printed on 10,000 sheets. Even after continuous printing of 10,000 sheets, an image comparable to the initial one was obtained (10000). Image background stain (fog level) after continuous printing on one sheet: magenta 0.57, yellow 0.54, cyan 0.58, black 0.50). The total consumption of each toner per sheet was 206 mg in the initial stage and 226 mg after the continuous printing of 10,000 sheets, and the toner consumption was stable. However, when halftone with a printing rate of 50% was printed and the image density was measured, the density was 0.38 for magenta, 0.39 for yellow, 0.39 for cyan, and 0.35 for black, which were not sufficient. On the other hand, after continuous printing of 10,000 sheets, the roller surface of the developing blade and the developing roller was visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

Comparative Example 5 Four color toner particles of magenta toner, yellow toner, cyan toner and black toner were prepared in the same manner as in Example 4 except that the heat treatment step was not performed on the toner particles. The sphericity of each toner particle was 0.697 for magenta toner particles, 0.698 for yellow toner particles, 0.700 for cyan toner particles, and 0.695 for black toner particles.

The obtained toner particles of four colors were filled in respective developing machines of a full-color image forming apparatus equipped with four one-component non-contact type developing machines similar to the case of Example 1, and the photosensitive drums were charged. The electrostatic images of the respective colors formed above were sequentially developed to form a full-color toner image on the intermediate transfer member, and this image was further transferred and fixed on a recording paper.

The background stain (fogging level) of the obtained image was measured by using a color difference meter. As a result, magenta was 0.66, yellow was 0.62, cyan was 0.69, and black was 0.70. Was obtained. Further, when replenishing the recording paper and toner appropriately, a full-color image with a printing rate of 5% was continuously printed on 10,000 sheets. Even after continuous printing of 10,000 sheets, an image comparable to the initial one was obtained (10000). Image background stain (fog level) after continuous printing on one sheet: magenta 0.66, yellow 0.60, cyan 0.65, black 0.68). The total consumption of each toner per sheet was 215 mg in the initial stage and 230 mg after continuous printing of 10,000 sheets, and the toner consumption was stable. However, when a halftone with a print ratio of 50% was printed and the image density was measured, the density was 0.45 for magenta, 0.40 for yellow, 0.44 for cyan, and 0.46 for black, which were not sufficient. On the other hand, after continuous printing of 10,000 sheets, the roller surface of the developing blade and the developing roller was visually observed, but neither fusion of the toner to the developing blade nor abrasion of the developing roller was confirmed.

[0071]

As described above, according to the present invention,
Even in long-term continuous printing, the amount of toner consumed for development is stable, and there are no problems such as fusion of toner to the developing roller or developing blade in the developing machine and abrasion of the developing roller due to toner. It is possible to stably obtain a good image without lowering the image density.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus used in an image forming method of the present invention.

FIG. 2 is a schematic configuration diagram showing another example of an image forming apparatus used in the image forming method of the present invention.

[Explanation of symbols]

10 ... Photosensitive drum 20 ... Developing machine 21 ...
Developing roller 22 ... Developing blade 23 ... Toner filling section 25 ... Toner supply roller 26 ... Toner control blade 30 ... Intermediate transfer body 40 ... Fixing device

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[Procedure amendment]

[Submission date] March 26, 2002 (2002.3.2)
6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Electrostatic image developing toner and image forming method

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION The present invention provides an electrostatic used for developing an electrostatic image formed by electrophotography or the like
The present invention relates to an image developing toner and an image forming method using the same.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art In an image forming system using electrophotography, generally, an electrostatic image is formed on a photoconductor containing a photoconductive material, and then the electrostatic image is developed with a developer called toner, and then the electrostatic image is developed. The toner image is transferred to a recording material such as paper and fixed. As the toner, a toner in which a colorant (pigment or dye) is dispersed in a thermoplastic resin binder resin and then pulverized to a desired particle size is used.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The present invention has been made in view of the above conventional circumstances, and increases the toner consumption amount, the fusion of the toner to the developing roller and the developing blade, the abrasion of the developing roller due to the toner, and the image of the intermediate tone. A static image that gives good development image quality over a long period of time without the problem of density loss
An object of the present invention is to provide a toner for image development and an image forming method.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In order to achieve the above object, the invention according to claim 1 has a number average molecular weight (Mn) of 3000 to 7000, which comprises at least a bisphenol A propylene oxide adduct and fumaric acid as monomer components. , Weight average molecular weight (Mw) 21000 to 27,000, weight average molecular weight (M
w) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8000 to 12000, binder resin mainly composed of polyester resin having acid value of 12 or less, and colorant, and having sphericity An electrostatic image developing toner comprising toner particles of 0.75 or more.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The invention according to claim 2 is the static according to claim 1.
In electro- development toner, the sphericity of toner particles is 0.75
The toner for electrostatic image development is characterized in that

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The invention according to claim 3 is the invention according to claim 1 or 2.
In the electrostatic image developing toner described above, the toner particles further include a non-oxidative polypropylene wax having a weight average molecular weight (Mw) of 2000 to 5000, an ester wax having an acid value of 10 or less, and an acid value of 10 or less. An electrostatic image developing toner containing carnauba wax and at least one selected from the group of paraffin wax having a weight average molecular weight (Mw) of 600 to 1500.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In order to achieve the above object, the invention according to claim 4 has a number average molecular weight (Mn) of 3000 to 7,000 and a weight average molecular weight of at least bisphenol A propylene oxide adduct and fumaric acid as monomer components. (Mw) 21,000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8,000 to 12000, binder resin mainly composed of polyester resin having an acid value of 12 or less, and coloring An electrostatic image developing toner containing a toner particle having a sphericity of 0.75 or more, which is formed on an electrostatic image bearing member.
An image forming method comprising a step of developing an electrostatic image .

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

In the electrostatic image developing toner and the image forming method having the above-mentioned constitution, the amount of toner consumed for the development is stable even in the long-term continuous printing, and the toner on the developing roller or the developing blade in the developing machine is kept stable. Problems such as fusing and abrasion of the developing roller due to toner do not occur, and the density of the intermediate tone does not decrease, and good images can be stably obtained.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The electrostatic image developing toner of the present invention has a number average molecular weight (Mn) of at least bisphenol A propylene oxide adduct and fumaric acid as monomer components.
Mainly polyester resin of 00 to 7000, weight average molecular weight (Mw) 21000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight in molecular weight distribution of 8000 to 12000, and acid value of 12 or less And toner particles containing a binder resin and a colorant.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

In addition, in the electrostatic image developing toner of the present invention, a charge control agent for controlling the charging property of the toner, a dispersing resin for enhancing the dispersibility of the colorant, and a fluidity of the toner are added, if necessary. You may make it contain a fluidizing agent etc. for raising. As the charge control agent, boron benzoyl complex, phenol condensation type calixarene, zinc salicylate metal complex, chromium salicylate metal complex, aluminum salicylate metal complex, etc. Can be used. The content of this charge control agent is usually 0.01 to 20 parts by weight, preferably 100 parts by weight of the binder resin, preferably
0.5 to 5 parts by weight.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Next, an image forming method of the present invention using such an electrostatic image developing toner will be described. The image forming apparatus used in the image forming method of the present invention is not particularly limited as long as it uses a developing method using a one-component non-magnetic toner, and particularly, an image as shown in FIG. 1 or FIG. It is preferable to use a forming device.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

That is, FIGS. 1 and 2 are schematic configuration diagrams showing an example of an image forming apparatus suitable for the image forming method of the present invention. FIG. 1 shows an image provided with a one-component non-contact developing machine. An example of the image forming apparatus, and FIG. 2 is an example of an image forming apparatus including a one-component contact type developing machine. It should be noted that in these figures, common parts are denoted by the same reference numerals, and redundant description is omitted. Further, in these examples, a photoconductor is used as the electrostatic image carrier.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

In these figures, 10 is an electrostatic charge on the surface.
A photosensitive drum on which an image is formed.
Are rotated clockwise in the figure.

[Procedure Amendment 16]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Reference numeral 20 denotes a developing device for developing the electrostatic image formed on the photosensitive drum 10, which is provided on the photosensitive drum 10.
A developing roller 21 which is disposed opposite to each other in a non-contact (FIG. 1) or contact (FIG. 2) state and is driven to rotate counterclockwise in the figure, at least the outermost layer of which is a conductor layer, and toner on the developing roller 21 And a developing blade 22 for forming a layer. The developing blade 22 is in contact with the developing roller 21 at a flat portion near the center from the free end, but the free end may be lightly pressed into contact with the developing roller 21. In the present invention, it is preferable that at least the outermost layer of the developing roller 21 is made of conductive rubber, and the developing blade 22 is made of metal,
Alternatively, it is preferable to use a resin or rubber stuck to only one part (contact part with the developing roller 21) thereof.
A developing bias voltage is applied to the conductor layer on the surface of the developing roller 21.

[Procedure Amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

The toner filled in the toner filling section 23 is
The toner supply roller 25 and the toner control blade 26 control the amount of the toner to be supplied to the developing roller 21, and the developing blade 22 regulates the amount of the toner, and the toner passes through the contact portion between the developing blade 22 and the developing roller 21. Is charged and the developing roller 21
A charged toner layer having a uniform thickness is formed on the surface of the. The toner layer formed on the surface of the developing roller 11 develops the electrostatic image formed on the photosensitive drum 10.

[Procedure 18]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

In the above-mentioned image forming method using the toner for electrostatic image development of the present invention, the amount of toner used does not increase even during long-term continuous use, and the toner is fused to the developing blade or developing roller. Also, abrasion of the developing roller is suppressed. Further, the reduction of the image density of the intermediate tone is also prevented. Thereby, it is possible to stably obtain a high quality image for a long period of time.

[Procedure Amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

Although the above-mentioned image forming apparatus is of a type in which the toner image is transferred onto the recording paper via the intermediate transfer body, it may be of a type in which the toner image is directly transferred without passing through the intermediate transfer body. In addition, the developing machine configured as above is
The image forming apparatus provided with the base is useful as an apparatus for forming a full-color image using the toner for electrostatic image development of the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 504 G03G 9/08 331 507 15/08 507E 507L F term (reference) 2H005 AA01 AA06 AA15 AA21 CA08 CA13 CA14 EA06 EA10 FA07 2H077 AB03 AB14 AC04 AD02 AD06 AD13 AD17 AD23 AE03 EA13 EA15 EA16 FA12 FA22 FA25 GA03

Claims (5)

[Claims] 1. A monomer component containing at least bisphenol A propylene oxide adduct and fumaric acid.
Number average molecular weight (Mn) 3000 to 7,000, weight average molecular weight (M
w) 21,000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight 80 in molecular weight distribution
For electrostatic image development, characterized in that it contains a toner resin containing 00 to 12000, a polyester resin having an acid value of 12 or less as a main component, and a colorant, and having a sphericity of 0.75 or more. toner. 2. The toner for developing an electrostatic latent image according to claim 1, wherein the sphericity of the toner particles is 0.75-1. 3. The toner particles further include a non-oxidizing polypropylene wax having a weight average molecular weight (Mw) of 2000 to 5000, an ester wax having an acid value of 10 or less, a carnauba wax having an acid value of 10 or less, and a weight average. Molecular weight (M
W) contains at least one selected from the group of 600 to 1500 paraffin waxes.
Or the toner for developing an electrostatic image according to 2. 4. A monomer component containing at least bisphenol A propylene oxide adduct and fumaric acid.
Number average molecular weight (Mn) 3000 to 7,000, weight average molecular weight (M
w) 21,000 to 27,000, weight average molecular weight (Mw) / number average molecular weight (Mn) 3 to 9, peak molecular weight 80 in molecular weight distribution
A toner for electrostatic image development containing a toner resin having a sphericity of 0.75 or more, containing a binder resin mainly composed of a polyester resin having an acid value of 12 or less and an acid value of 12 or less. An image forming method comprising a step of developing an electrostatic latent image formed on a latent image carrier. 5. A developing roller, at least the outermost layer of which is made of conductive rubber, a developing blade mainly made of metal, a toner supply roller for supplying toner to the developing roller, and a toner supply roller arranged close to the developing roller. 5. The image forming method according to claim 4, wherein the image forming method is carried out by using a one-component developing machine equipped with a toner supply roller and a toner control blade for controlling the amount of toner supplied to the developing roller.