JPH1048876A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method improved in image characteristics, long-term durability, environmental stability (characteristics at high temp. and high humidity environment or storage characteristics). SOLUTION: An electrostatic charge latent image is developed by using a developing device 7 which has at least a developing roller to develop an electrostatic charge latent image formed on an electrostatic charge image holding body 1 with a toner 8 held by a developing roller. In this method, the developing device has such a mechanism that development is performed by bringing the toner on the developing roller on which the developer deposits while being in contact with the electrostatic charge image holding body which faces the roller. The toner has <=10μm weight average particle size, and the amt. of toner having >=12.7μm particle size is <20wt.%. When a rectangular parallelepiped circumscribed with the toner particle is supported and respective sides a, b, c thereof satisfy a>b>c, a>b=c, a=b>c or a=b=c, the average of b/a is 0.4 to 0.98 and the average of c/a is 0.3 to 0.95.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method using an electrostatic image developing toner which is applied to an electrophotographic method, an electrostatic recording method, a magnetic recording method and the like.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
(U.S. Pat. No. 3,666,363) and Japanese Patent Publication No. 43-24748 (U.S. Pat.
1,361), etc., a number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various methods. ,
Next, the latent image is developed with a toner to form a visible image, and if necessary, a toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure or the like to obtain a copy.

Various developing methods for visualizing an electrostatic latent image using toner have been known. For example, U.S. Pat.
74,063, a magnetic brush method,
The cascade developing method described in US Pat. No. 2,618,552 and the powder cloud method, fur brush developing method, liquid developing method described in US Pat. No. 2,221,776 are known. ing.

Heretofore, several developers have been proposed for the purpose of improving image quality in these developing methods.

Particularly, in recent years, the functions of image forming apparatuses using electrophotography, such as copying machines and printers, have been diversified, and there has been a demand for higher definition and higher image quality. Further, the storage environment of the toner and the cartridge filled with the toner is various, and severe storage stability is required.

Conventionally, for example, JP-A-51-3244 proposes a non-magnetic toner intended to improve image quality by defining a particle size distribution. In this toner, a toner having a particle diameter of 8 to 12 μm is mainly used,
Relatively coarse, faithful placement on the latent image is insufficient. Such a coarse toner particle, it is necessary to fill the gap between the toner particles by thickly overlapping the toner particles to form a clear image using a broad particle size distribution, the predetermined image There is also a problem that the amount of toner required to obtain the density increases.

In Japanese Patent Application Laid-Open No. 54-72054, the size of particles having an intermediate weight is as coarse as 8.5 to 11.0 μm, and there is still room for improvement as a high-resolution toner. Japanese Patent Application Laid-Open No. Sho 58-129439 proposes a non-magnetic toner having an average particle diameter of 6 to 10 μm and a maximum number of particles of 5 to 8 μm. There is a tendency that an image having little sharpness is formed.

For this reason, Japanese Patent Application Laid-Open No. 2-284151 discloses that toner particles of 5 μm or less are effective for improving the image quality such as reproducing the contour of a latent image. However, when the particle diameter is controlled in a fine direction, there is a problem that the fluidity of the toner is reduced. In addition, in toners that can be fixed at a low temperature for the purpose of energy saving and shortening of waiting time, contamination on a developing roller, a charging member, a surface material of a photoreceptor, etc. is more likely to occur as the particle diameter becomes smaller. There was a limit to use over In addition, when the particle diameter is small, unevenness of electrification is likely to occur. Further, the fine particles of the charged toner have a problem that the Coulomb force with the surface of the developing roller is increased and the toner is easily aggregated on the developing roller.

As means for solving this phenomenon, the chance of contact between the developing roller and the toner is increased by applying the toner extremely thinly on the developing roller, the magnetic toner is supported by the magnetic force, and the magnet and the toner are relatively moved. Attempts have been made to dissolve the toner particles from each other by moving them, and to cause friction with the developing roller. However, no solution has yet been obtained.

Japanese Patent Application Laid-Open Nos. 1-112253 and 2-284158 propose toners having a small particle diameter. In Japanese Patent Application Laid-Open No. 1-185653, the degree of spheroidization is specified for a toner having a size of 14 μm or less. However, it is difficult to achieve halftone or uniformity of a solid image by using only the toner. At present, it is insufficient to satisfy the demand for fine development.

In recent years, a so-called contact one-component developing method has been proposed in which development is performed by using a semiconductive developing roller or a developing roller having a dielectric layer formed on its surface to press against a photosensitive member surface layer. I have.

For example, Japan Hardcopy
A study of a contact-type one-component non-magnetic developing system has been made on pages 25 to 28 of the '89 Transactions. FUJITSU Sc
i. Tech. J. , 28,4, pp. 473-480
(December 1992) reports an outline of a printer using a one-component contact developing method. Also, JP-A-5-188765 and JP-A-5-188
No. 752 discloses a technique relating to a one-component contact developing method.

In the contact one-component developing method, since the surface of the image bearing member and the developing electrode are very close to each other, it has been pointed out that advantages such as reduction of the edge effect of development can be obtained. However, there is a problem due to the contact between the surface of the image carrier and the toner carrier, and there is a limit to the applicable range.

For example, JP-A-63-208062 discloses a glass transition point of 50 ° C. or higher and a softening point of 110 to 160.
Although an example is shown in which colorant particles and opposite polarity particles are added to particles at a temperature of ° C., this alone does not only provide a sufficiently high image quality, but also has a fixing property equal to or lower than that of the previous toner. That has been confirmed. Japanese Patent Application Laid-Open No. 2-8862 discloses an example in which the hardness of the thickness regulating member is increased in the developer. However, while the material of the thickness regulating member is limited, the developing roller and the electrostatic image holder are limited. However, contamination and scraping of the fixing member and the like have not been solved.

Another problem particularly caused by the contact between the developing roller and the electrostatic image holder is that the toner on the developing roller is pressed by the electrostatic image holder.
One of the reasons is that toner leaks toward the end. Further, on the other hand, in the case where a toner having a spherical shape is used as a means for smoothly replenishing the toner to the developing roller and a toner having excellent fluidity is used, toner leakage is particularly remarkable in an edge direction. .

As a result, not only the transfer member conveying member, the developing roller rotating gear, the driving parts such as the motor, but also the exposure device for forming an electrostatic image are contaminated to some extent.
For this reason, it has been necessary to periodically clean the inside of the developing device and replace parts.

An example using a toner supply roller is disclosed in Japanese Patent Application Laid-Open No. 4-34580. However, even when these supply rollers are used, the problems specific to contact development have not been solved.

That is, when such a developing method is used,
It is essential that the surface of the electrostatic image carrier is rubbed with the toner and the developing roller. For this reason, it causes deterioration of the toner due to long-term use, deterioration of the surface of the developing roller, deterioration of the surface of the electrostatic image carrier or wear, and the like. Deterioration remains as a problem, and the conventional technology has not sufficiently solved the problem, and a technology for improving durability characteristics has been desired.

As the developing roller used in the development of the above-mentioned method, for example, a roller obtained by treating the surface of a cylindrical molded product by electrolysis, blasting, sanding or the like so as to have a predetermined surface roughness is used. However, in this case, the toner existing near the surface of the developing roller by the regulating member has a very high charge, and is strongly attracted to the surface of the developing roller, which reduces the chance of friction between the toner and the developing roller. The toner will not be able to carry a suitable charge. Under such circumstances, sufficient development is not performed, resulting in unevenness and scattering of the image.

In order to prevent the generation of such an excessively charged toner, a method of forming a film in which a conductive fine powder such as carbon black is dispersed in a resin on the developing roller is disclosed in Japanese Patent Application Laid-Open No. HEI 11-124,087. -277265 has been proposed. Further, Japanese Patent Application Laid-Open No. 5-6089 proposes a method of forming irregularities on a metal cylindrical tube by blasting or the like and then providing a film on the surface in order to increase the surface roughness. However, sufficient dispersibility, abrasion resistance and peeling resistance of the additive have not yet been obtained.

An important one of the properties required for the toner is the fixing performance.

Various methods and apparatuses have been developed for the fixing step, but the most common method at present is a pressure heating method using a heat roller.

In the pressure heating method using a heating roller, the fixing is performed by allowing the toner image surface of the sheet to be fixed to pass through the surface of the heat roller, which is formed of a material having releasability from the toner, under pressure. Is what you do. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the heat efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers. However, in the above-mentioned method, since the surface of the heat roller and the toner image are in contact with each other under pressure in a molten state, a part of the toner image adheres and transfers to the surface of the fixing roller, thereby fouling the next sheet to be fixed ( Offset phenomenon). Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

Further, recently, instead of a heat roller, a fixing device comprising a pressing member which is in pressure contact with a heating member and which makes a recording material adhere to the heating member via a film has been put into practical use. However, since the toner surface melts, the offset phenomenon is more likely to occur, and it is necessary to prevent this.

In order to make full use of these fixing performances, it is important how to mount on the electrostatic image holder in the developing step. Generally, in order to obtain a good image, it is necessary to uniformly apply the toner to the surface of the developing roller. That is, for example, the regulating member (elastic blade) 13 is applied to the developing roller (toner carrier) 9 shown in FIG.
The toner in the toner container is conveyed by the rotation of the developing roller, and is extremely thinly and uniformly applied to the surface of the developing roller by a blade or the like. Therefore, the toner is required to have fluidity and aggregation resistance. Therefore, it is necessary to improve the properties of the toner.

Many studies have been made to improve the toner fixing performance.

For example, in order to prevent the toner from adhering to the surface of the fixing roller, the roller surface is formed of a material such as a fluororesin which is excellent in releasability from the toner, and the surface of the roller is further prevented from being offset by silicone oil or the like. It has been practiced to supply a liquid for use and coat the roller surface with a thin film of liquid. Although this method is extremely effective in preventing offset of the toner, it generates an odor by heating the offset preventing liquid,
Since a device for supplying the liquid for preventing offset is required, there is a disadvantage that the mechanism is complicated and high precision is required, so that the device is expensive.

JP-B-58-58664, JP-B-5-58664
Japanese Patent Application Laid-Open No. 7-52574 discloses a toner or a heating roller fixing method which is effective in preventing toner adhesion due to offset to a heating roller by using a low molecular weight polyalkylene. As a result,
In this method, contamination of the lower roller of the fixing device (hereinafter referred to as a pressure roller) cannot be prevented, and the heating roller fixing device has a small diameter of 40 cm or less and / or the linear speed of the heating roller fixing device is low, and is less than 150 mm / sec. In this case, the effect is small, and it is necessary to supply the anti-reoffset liquid.

Also, JP-A-52-3304, JP-A-52-3305, JP-A-57-52574, JP-A-61-138259, and JP-A-56-8
JP-A No. 7051, JP-A-63-188158, JP-A-63-113558, and the like disclose techniques containing waxes in a toner. In addition, Japanese Unexamined Patent Publication
In JP-A-166554, the glass transition point and the melt viscosity of the toner binder are specified, and in JP-A-5-241351, the condition of the peak of the molecular weight distribution is specified. In these methods, a relatively large particle diameter of 10 μm
This is effective when a large amount of the above toner is contained, but when the toner having a small particle diameter according to the invention is used,
Sufficient performance has not always been obtained.

On the other hand, when the toner particle size is reduced for the purpose of gluing more faithfully to the latent image for higher image quality,
The dispersion state of the charge control agent and the colorant greatly affects the chargeability of the toner. As a method for controlling the charge of the toner used for the electrostatic image developing toner, there are dyes, pigments, and the like, which are generally called charge control agents, and a chromium complex compound is mainly used to give a negative charge.

On the other hand, in recent years, from the viewpoint of environmental protection, the primary charging and transfer process using a corona discharge, which has been conventionally used, to the primary charging and transfer process using an electrostatic image holding member contact member are becoming mainstream. is there.

For example, JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to a contact charging method and a contact transfer method, but a conductive elastic roller is brought into contact with the electrostatic latent image holding member,
The electrostatic latent image holding member is uniformly charged while applying a voltage to the conductive roller, and then another voltage is applied to the electrostatic latent image holding member after obtaining a toner image by an exposure and development process. The transfer material is passed through the conductive roller while pressing the conductive roller, and the toner image on the electrostatic latent image holding member is transferred to the transfer material. Then, an image is obtained through a fixing process.

However, in such a roller transfer system that does not use corona discharge, the transfer member comes into contact with the electrostatic image holding member via the transfer member during transfer.
When the toner image formed on the electrostatic image holding member is transferred to a transfer material, the toner image is pressed against the transfer material, and a problem of partial transfer failure called so-called missing transfer is likely to occur.

Further, toner particles remaining on the electrostatic image carrier without being transferred onto the transfer material are removed from the electrostatic image carrier by a cleaning process.

For this cleaning step, conventionally, blade cleaning, fur brush cleaning, roller cleaning and the like have been used. In each of these methods, the transfer residual toner is mainly mechanically scraped off or dammed and collected in a waste toner container. Therefore, there has been a problem caused by such a member being pressed against the surface of the electrostatic image holder. For example, pressing the member strongly wears the electrostatic image holder to shorten its life.

From the viewpoint of the apparatus, the provision of such a cleaning apparatus inevitably increases the size of the apparatus, which has been an obstacle to downsizing the apparatus.

Further, from the viewpoint of ecology, there has been a demand for a system that does not generate waste toner in terms of effective utilization of toner.

The disclosure of a technique conventionally referred to as simultaneous cleaning or cleanerless development focuses on a positive memory, a negative memory, and the like due to the influence of residual toner on an image as disclosed in JP-A-5-2287. Was something. However, as the use of electrophotography advances, the need to transfer toner images to various transfer materials has emerged, and in this sense, it has not been satisfactory for various transfer materials.

JP-A-59-222851 and JP-A-1-185563 require means for achieving a two-component developer using a spherical toner and a spherical carrier, and the developing method differs from that of the present invention. In addition, it has been confirmed that this alone is not enough to achieve high image quality in various environments. In particular, when the toner is reduced in particle size in order to obtain high image quality, the adverse effect of charge-up due to spheroidization becomes remarkable, and contamination of the developing roller, the electrostatic image holder, the contact charging member, the fixing device, etc. Had the problem of causing Japanese Patent Application Laid-Open No. 2-51168 seeks a means for obtaining stable charging characteristics by using a spherical toner and a spherical carrier, and does not refer to a conventional toner obtained by a pulverization method. Was.

In particular, it is one of the major problems in the present invention to solve the problem of charge-up due to spheroidization, unlike the conventional idea of improving performance by merely spheroidization.

Particularly, in the cleaning step for removing the toner remaining on the electrostatic image holding member after the transfer step, a problem is likely to occur when a toner having a relatively small particle diameter is used. The reason is that, in the case of a toner having a relatively small particle diameter, a large amount of ultrafine powder components are contained in the toner, and when these are developed and adhere to the photoreceptor, a strong adhesive force is exhibited. In the step of transferring to a member,
This ultrafine powder component tends to remain on the electrostatic image carrier.
Furthermore, it is difficult to clean the electrostatic image holder by peeling off the ultrafine powder component due to its strong adhesive force.

Various methods are known for cleaning the electrostatic image holder, and blade cleaning is known as a highly efficient cleaning method. When trying to clean the ultrafine powder component by using blade cleaning, the blade contact pressure against the electrostatic image holder must be increased to prevent the superfine powder component from slipping through. In this case, since the surface of the electrostatic image holding member is more strongly rubbed by the blade or toner attached to the blade, the charging ability of the electrostatic image holding member is damaged or uneven shaving becomes a scratch on the image. And the life of the electrostatic image holder is shortened.

Further, in a toner containing a large amount of ultrafine powder components, the inorganic oxide fine particles are required to increase the cohesive force of the toner, maintain good charging characteristics and fluidity, and achieve desired high image quality and high resolution. In many cases, it is necessary to add a fluidity-imparting agent or a charge-imparting agent more than before.
When a large amount of a fluidity imparting agent such as inorganic oxide fine particles is added,
Since these enter between the electrostatic image holder and the blade, the electrostatic image holder is easily damaged and easily slipped between the blades, so that the blade contact pressure on the photoreceptor must be increased to prevent slippage. This promotes scratching and scraping of the electrostatic image holder and shortens its life.

Conventionally, since the electrostatic image carrier contains a large amount of a photosensitive material and / or a charge transporting substance, its durability has been limited in order to maintain its sensitivity and charge transporting ability. Therefore, many studies have been made on providing a protective layer made of resin or the like on the surface of the electrostatic image holder. However, due to the provision of a layer in which electric charges do not move due to the structure of the photosensitive layer, there have been problems such as an increase in residual potential and a decrease in sensitivity due to the durable use.
It is also known that this problem can be improved by reducing the thickness of the protective layer. In this case, there is a problem that the wear of the protective layer itself progresses due to repeated use of the photoconductor, and the life of the protective layer is shortened by reducing the film thickness. In order to adjust the resistance of the protective layer, attempts have been made to add conductive fine particles to the protective layer. However, even when the protective layer is provided on the outermost layer of the electrostatic image carrier, the protective layer is not damaged. If it is applied, there is a similar problem that appears as an image defect and causes cleaning failure.

In short, in order to improve the fixing performance,
When a toner that is soft to heat is used, it is difficult to satisfy durability because the toner tends to adhere to a developing roller electrostatic image holder, a contact charging member, and the like.

On the other hand, when the toner contains a large amount of low molecular weight components such as a wax component, there is a problem in chargeability, which causes problems such as a decrease in density and fog.

As described above, it is the present situation that a material having excellent image quality and satisfying all of durability, fixing property, environmental stability and the like has not yet been obtained.

[0048]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to significantly improve the disadvantages of the prior art, realize high-quality images, exhibit high developability, and maintain image formation for a long period of time. It is to provide a method.

Further, an object of the present invention is to provide a high image density and a high image density in a wide range of environments from low to high temperatures and low to high humidity.
An object of the present invention is to provide an image forming method which realizes high-quality image formation with high resolution and almost no fog, and exhibits high durability.

It is a further object of the present invention to provide an image forming method which has high image quality, high fixing performance and high offset resistance.

It is a further object of the present invention to provide an image forming method which does not cause uneven charging even when a large number of images are formed in an image forming method having a contact charging step.

Further, the object of the present invention is to prevent the contact charging member from being contaminated even when the developing system for charging the electrostatic latent image holding member using the contact charging member is used, and thus the surface resistance is not increased. An object of the present invention is to provide an image forming method which does not cause charging failure.

[0053]

According to the present invention, there is provided a developing device having at least a developing roller which rotates while carrying a toner on a surface thereof and develops an electrostatic latent image formed on an electrostatic image carrier with the toner. In the image forming method for developing an electrostatic latent image by using a developing device, the developing device comprises a developing device, which is provided with an electrostatic image holding member provided with a toner on a developing roller that adheres and transports a developer onto a surface during development. The toner has a weight average particle size of 10 μm or less, and a content of 12.7 μm or more in the particle size distribution is 20% by weight or less. When one side of each of the cuboids is imagined, a>b> c or a>
When a, b, and c are defined so that b = c or a = b> c or a = b = c, the average of b / a is equal to 0.
The present invention relates to an image forming method having a shape having a shape of 4 to 0.98 and an average of c / a of 0.3 to 0.95. Hereinafter, the “present invention 1” particularly means an invention having this configuration.

Further, according to the present invention, an electrostatic charge is provided by using a developing device having at least a developing roller which carries a toner on its surface, rotates, and develops an electrostatic latent image formed on an electrostatic image carrier with the toner. In the image forming method for developing a latent image, the developing device develops the toner while contacting the toner on a developing roller that transports the developer by attaching the developer to the surface during development. The toner has a weight average particle size of 10 μm or less, and a content of 12.7 μm or more in the particle size distribution is 20% by weight or less, and the toner has a heat absorption peak at 45 to 115 ° C. And a component having the following formula:
Hereinafter, the “invention 2” particularly means an invention having this configuration.

Further, according to the present invention, there is provided a developing device having a developing roller having at least a developing roller which rotates while supporting a toner on a surface thereof and develops an electrostatic latent image formed on an electrostatic image holder with the toner. In the image forming method for developing a latent image, the developing device develops the toner while contacting the toner on a developing roller that transports the developer by attaching the developer to the surface during development. The absolute value of the charge amount is larger at the end of the developing roller than at the center of the developing roller, and the weight average particle size of the toner is 1
0 μm or less, and the content of 12.7 μm or more in the particle size distribution is 20% by weight or less, and each side of the rectangular parallelepiped when imagining a rectangular parallelepiped to the toner is a>b>
c or a> b = c or a = b> c or a =
When a, b, and c are defined so that b = c, b / b
The average of a is 0.4 to 0.98 and the average of c / a is 0.3
The present invention relates to an image forming method having a shape of about 0.95, wherein the relationship between the shape of the toner and the charge amount satisfies the following expression. Hereinafter, the “invention 3” particularly means an invention having this configuration.

C / a × 12 + 3 ≦ | Q | ≦ c / a × 16 + 41 (| Q |: absolute value of toner charge amount)

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reason why the above object is achieved by the image forming method of the present invention is presumed as follows.

It is extremely important to make the toner particles small for forming a high-definition image.

In the conventionally used toner, the placement on the latent image is insufficient in terms of the fidelity, and unevenness occurs due to the size of the particle size. In particular, in solid images, by increasing the amount of applied toner, the unevenness in appearance was reduced, so in line images, toner scattering occurred in the transfer process and fixing process of the developing device, and image quality such as resolution was poor. Was inferior. It is a feature of the present invention to utilize the small toner particles for forming a high-definition image.

Further, in the present invention, since the toner comes into contact with the electrostatic image holder during development, faithful placement of the toner on the electrostatic image holder is achieved. That is, since the image is less likely to be disturbed by the flying toner, an image having a high resolution can be obtained. The problem at this time is that the toner, the electrostatic image holder, and the developing roller are worn out and deteriorated by fusion due to the contact, and the toner causes pressure between the electrostatic image holder and the developing roller due to the contact. This is a toner leak due to receiving. Resolving this problem is a major feature of the present invention.

That is, the fluidity of the toner is maintained by adjusting the shape of the toner optimally, or by including a component having an absorption caloric peak at 45 to 115 ° C. in the toner. And non-uniformity and disturbance of the image due to contamination of the electrostatic image holder and the like. According to this image forming method,
There is an advantage that the toner is hardly charged up and the charged state is stabilized. Further, since the absolute value of the charge amount is larger at the end of the developing roller than at the center of the developing roller, toner leakage can be prevented. Further, it is possible to reduce the difference in the environment of the toner chargeability, and the life of the electrostatic image holder, the developing roller, and the like can be extended without being affected by the difference in the environment.

In the present invention 1, one of the great effects is to solve the problem of charge-up due to the spheroidization, unlike the conventional idea of improving the performance by simply spheroidization.

In short, in the toner used in the first aspect of the invention, when a rectangular parallelepiped circumscribing the toner is imagined, each side of the rectangular parallelepiped is defined as a>b> c or a> b = c
Alternatively, when a, b, and c are defined so that a = b> c or a = b = c, the average of b / a is 0.4 to
One feature is that it has a shape of 0.98 and the average of c / a is 0.3 to 0.95.

It is important that the shape of the toner satisfies the above equation in order to obtain a high-definition image faithful to a satisfactory latent image. When the values of b / a and c / a are small with respect to the above equation,
That is, when the shape of the toner particles is flatter, the stability of the toner is lowered, and a problem occurs particularly in the point of aggregation resistance. Further, the charging is lacking in uniformity, fogging and low density due to poor charging are liable to occur, and the developing roller and the electrostatic image holder are easily contaminated.

In the present invention 2, in particular, unlike the conventional idea of improving the fixing performance using only low-molecular-weight polyethylene or polypropylene, the durability against the electrostatic image holder, the developing roller, the contact charging member and the like by contact development is improved. One of the great effects is solving the harm.

In short, one feature of the toner used in the present invention 2 is that the toner contains a component having a heat absorption peak at 45 to 115 ° C.

In particular, when the acid value of the binder resin of the toner is A and the position of the maximum endothermic peak among the components contained in the toner and having a heat absorption peak at 45 to 115 ° C. is B ° C. , 55 ≦ B−2 × A ≦ 105, a great effect is obtained.

It is important that the toner satisfies the above expression in order to obtain a high definition image and a fixing / fusing performance faithful to a satisfactory latent image.

In the above formula, when the value of B−2 × A is smaller than 55, that is, when the position of the peak of the maximum amount of absorbed heat is low and the acid value is large, the charging lacks uniformity.
Fog and low density due to poor charging are likely to occur.

When the position of the peak of the maximum amount of absorbed heat is particularly low, the stability of the toner is low, and the developing roller and the electrostatic image carrier are easily contaminated. Problematic. B-
When the value of 2 × A is larger than 105, that is, when the position of the maximum heat absorption peak is high and the acid value is low, the effect of the component having the heat absorption peak at 45 to 115 ° C. becomes small, and the fixing member is contaminated. Tends to occur.

On the other hand, in the present invention 3, since the toner on the developing roller is in contact with the electrostatic image carrier, not only the charging property with the developing roller but also the charging property with the electrostatic image carrier is important. However, this can be simulated by knowing the relationship between the two-component frictional charge and the shape of the toner, which is the method of measuring the charge Q of the present invention 3 using the used toner. Was found.

Further, in the present invention 3, unlike the conventional idea of improving the performance in the mere contact developing method, the problem of the durability against the in-machine contamination due to the contact development and the problem of the image resolution are solved. Is one of the major effects. Simply having a larger absolute value of the charge amount at the end of the developing roller than at the center of the developing roller is not sufficient in terms of the life of the electrostatic image holder, the developing roller, and the like.

In short, the developing roller used in the present invention 3 is characterized in that there is a difference between the charge amount at the center and the charge amount at the end. When the charge amount at the center is qc and the charge amount at the end is qe, 0.4 ≦ | q
e−qc | ≦ 14.5, more preferably 0.8 ≦ | q
A great effect can be obtained when e-qc | ≦ 5.6 is satisfied. Satisfying the above expression is more effective in obtaining high-definition image quality faithful to the latent image and in preventing toner leakage.

In particular, the inventors of the present invention have conducted intensive studies on the relationship between the above-described toner characteristics and the device configuration, and have found a relationship between the shape and behavior of the toner and a relationship between image quality during durability. Was.

As described above, particularly in the present invention, the contact between the electrostatic image carrier and the toner having excellent particle size distribution and shape or releasability on the developing roller provides a sharp and high resolution. A great feature is that an excellent image with less scattering of toner around the image can be obtained. Moreover, it is excellent in durability and storage stability, and is characterized in that the performance of the developing device can be maintained for a long period of time.

When the shape of the toner does not satisfy the above expression,
Alternatively, for example, the average of b / a is less than 0.4 or c / a
If the average is less than 0.3, the toner is not transferred much because the separability from the electrostatic image carrier is inferior. In particular, when the average of b / a is smaller than 0.3, the chargeability of the toner is inferior, but the fixing member is easily contaminated.

On the other hand, when the average of b / a exceeds 0.98 or when the average of c / a exceeds 0.95, the cost is high, the rise of the toner charge is deteriorated, and the saturation charge is reduced. The amount tends to be too large.

When the average of c / a is larger than 0.95, the lines around the image are slightly broken but worse. This is presumably because the fluidity of the toner is high, so that the unfixed image before the fixing step is easily disturbed and the adhesive force between the toner particles becomes unstable. Further, when the average of c / a is greater than 0.95, the fixability tends to slightly deteriorate.
Therefore, the average of b / a is 0.98 or less, and c /
The average of a needs to be 0.95 or less, preferably the average of b / a is 0.92 or less, and the average of c / a is 0.85 or less.

Although there have been reports on the use of the toner in the process of developing and transferring the toner at once and the polymerization method of forming the toner particles in a solvent in a limited form, it has been reported that the toner spheres are limited. In the above method, a conventional pulverizing means can be used. Means for achieving the toner shape in the present invention is, depending on the pulverizer, conditions, a method of melting the surface using heat,
An apparatus or the like that gradually scrapes the surface to round it is used.
In particular, when combined with the developing roller of the present invention, it is effective in improving the image quality.

The reason for this is that, in the developing method of the present invention capable of obtaining a high-definition image, since the electrostatic image carrier and the toner on the developing roller are always in contact with each other and are under pressure, the physical properties of the toner In particular, control of the shape is strictly required. By using the toner shape of the present invention,
Agglomeration resistance is increased, and problems such as agglomeration and fixation in the developing device and on the electrostatic image holder are less likely to occur. In addition, the particle size distribution is also important. If there are many coarse particles in the particle size distribution,
Since it becomes difficult to faithfully place the toner on the latent image on the electrostatic image holder, the weight average particle diameter of the toner is 10 μm.
m or less, and the content of 12.7 μm or more in the particle size distribution is 20% by weight or less in order to obtain a good image.

Further, according to the study of the present inventors, it has been found that the portion of 4 to 6 μm in the particle size distribution of the toner is important for obtaining a high definition image. However, since the portion having a size of 3.17 μm or less has a strong adhesive force to the developing roller, it is difficult to develop the image on the electrostatic image holding member, and an image defect is easily caused. So, more preferably,
When the weight average diameter D4 (μm) of the toner is 3.5 ≦ D4 ≦
9.5 and 3.17 μm in the number particle size distribution.
Those having a particle size distribution satisfying the relationship of 35-D4 × 5 ≦ N ≦ 180-D4 × 25 with respect to the abundance ratio N (number%) of particles of m or less are preferable. As a result, the chargeability and durability become more excellent, and a clearer image with less fog can be obtained.

According to the study of the present inventors, it has been clarified that the relationship with the charge amount is important for making the most of the shape of the toner. That is, in the present inventions 1 and 2, the absolute value | Q | of the charge amount of the toner is 6 mC / kg or more and 48 mC / kg in order to obtain better transfer, development and fixing properties.
The following have been found to be valid: Further, as a result of further study, when a rectangular parallelepiped circumscribing the toner is imagined, one side of each rectangular parallelepiped is defined as a>b> c or a> b = c or a = b> c or a = b = c When a, b, and c are defined so as to satisfy the following condition, it is extremely effective to satisfy the range shown in FIG. 6 (the fine hatched portion): −8 × c / a + 16 ≦ | Q | ≦ −28 × c / a + 56. It turned out to be relevant. That is, in a portion where | Q | is smaller than the hatched portion in FIG. 6, the transferability is deteriorated, and the amount of toner remaining on the drum increases. In addition, in a portion where | Q | is larger than the oblique line portion, image skipping increases, and an image lacking in sharpness tends to be formed.

In the present invention 3, for the same purpose as described above, the absolute value | Q | of the charge amount of the toner is 5 mC / kg or more and 58 mC
C / a × 12 + 3 ≦ | Q | ≦ c / a × 16 which is effective in the range shown in FIG.
It is extremely effective to satisfy +41.

In the present invention, in order to obtain a high-definition image, since the electrostatic image carrier and the toner on the developing roller are always in contact with and under pressure, the resin constituting the toner, the charge control agent, The performance of the mold is important.

One example is the control of the binder resin. That is, by controlling the existing state and the total amount of the acid contained in the binder resin of the toner, not only can improve the compatibility when a release agent such as a low-molecular weight wax is used, but also other toner components, for example, There are some which can be presumed to have a role of improving the dispersion of the colorant, the magnetic substance, the charge control agent and the like in the binder resin.

That is, by using this means to suppress aggregation of the charge controlling agent and the wax, it is possible to exhibit stable charging characteristics and maintain the blocking resistance of the toner particles while maintaining high developability. It seems to have contributed.

This has the effect of making it difficult to cause contamination on the contact charging member, the latent electrostatic image holding member, and the like. In addition, since the amount of scattered toner is small, even when the apparatus is applied to a high-speed machine, the result is that the in-machine contamination hardly occurs.

Further, according to the image forming method of the present invention, the fixability is good and the offset is hardly generated. This suggests that a component having releasability near the fixing temperature can stay on the surface of the toner, and it is inferred that the effect of anti-offset is generated.

It has also been found that when the release component is a low molecular weight wax, the fixability can be further improved.
However, when the toner does not contain a component having an absorption heat peak at 45 to 115 ° C., the developing roller, the electrostatic image holder, the contact charging member, and the like are easily contaminated, and the compatibility between the standing stability and the fixing property is improved. Becomes difficult.

Further, in the present invention, the resin composition of the toner binder resin preferably contains a component having an acid group such as a carboxyl group so that the total acid value is in the range of 0.1 to 40. If it is less than 0.1, the charge-imparting ability is low, and in a high-humidity environment, adverse effects such as fog are caused. On the other hand, if it exceeds 40, it is liable to be affected by moisture in the air, which tends to adversely affect the charging ability under high humidity. Also, the life of the developing roller tends to be shortened.

The MI of the toner is preferably in the range of 2 to 30. The reason for this is that if the MI is smaller than 2, the toner layer on the developing roller becomes slightly non-uniform, and the image quality tends to be slightly but inferior. Are likely to be present in the form of particles. If the MI is larger than 30, problems such as contamination of the contact charging member and toner adhesion to the fixing roller during thermal fixing are likely to occur. As these adjusting means, it is possible to change kneading conditions (temperature, strength) at the time of toner production, or to vary the compounding of the materials. It is also possible to use two kinds of charge control agents described below as a means.

The type of the binder resin of the toner used in the present invention is not particularly limited. For example, a homopolymer of styrene such as polystyrene and polyvinyl toluene and a substituted product thereof; a styrene-p-chlorostyrene copolymer Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile Copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene Styrene copolymers such as copolymers Coalescence; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin , Polyvinyl butyral, terpene resin, cumarone indene resin, petroleum resin and the like can be used. Further, a crosslinked styrene resin is also a preferable binder resin.

The resin composition according to the present invention may have various molecular weight distributions. Preferred binder resins have Mw of 150,000 to 300,000 in the molecular weight distribution measured by GPC. Yes, Mz is 1,000,000-1
Preferably it is 10 million. If the molecular weight is below this range, it is difficult to mix sufficiently during kneading, and the surface of the developing roller tends to deteriorate quickly. When the molecular weight is larger than this range, not only is it difficult to produce the resin, but also the pulverizability is remarkably deteriorated in producing the toner.

It is preferable that Mw / Mn is in the range of 8 to 65. If it is less than 8, the distribution is too narrow, and it is difficult to achieve both the fixing property and the adhesion resistance to the electrostatic image holder. If it exceeds 65, the distribution is wide, so that the high molecular weight component easily damages the electrostatic image holder and the low molecular weight component easily contaminates the fixing device.

The softening point temperature is preferably from 145 ° C. to 165 ° C. By being within this range, a sufficient viscosity can be obtained during kneading, and the dispersion of the toner components becomes good. As a result, stable charging performance, anti-contamination resistance of the developing roller, and anti-contamination property of the electrostatic image holder can be obtained. Because you can do it.

Further, the desirable binder resin composition preferably has a glass transition point Tg in the range of 54 to 75 ° C. When the Tg is lower than 54 ° C., it is difficult to achieve high fixing properties for a wide variety of transfer materials. 7
If the temperature is higher than 5 ° C., it is difficult to simultaneously satisfy a sufficient life of the developing roller, a sufficient life of the electrostatic charge image holding member, a storage property of the toner, and a fixing property. In particular, when the Tg is in the above range, the binder resin component can be made robust, stable charging characteristics can be obtained, and a high-quality image free from fog can be provided.

A colorant can be added to the toner. Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, and the like.
Bengala, phthalocyanine blue, induslen blue and the like. Further, for example, examples of the dye include anthraquinone dyes, xanthene dyes, methine dyes, and the like.
It is preferable to use 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 0 parts by weight.

On the other hand, a magnetic material can be contained.
For example, magnetite, ferrite, iron oxide and the like can be mentioned.

The wax preferably used in the present invention is
Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives,
Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products.

The component having a heat absorption peak at 45 to 115 ° C. used in the present invention 2 includes, for example, higher alcohols represented by the following general formula.

RY (R: hydrocarbon, Y: hydroxyl group, carboxyl group, alkyl ether group, ester group, sulfonyl group; weight average molecular weight (Mw) of RY by GPC of 3000 or less) Examples of compounds include: (a) CH ₃ (CH ₂ ) _n CH ₂ OH (n = about 20 to about 30)
_{0) (b) CH 3 (} CH 2) n CH 2 COOH (n = about 20 to about _{300) (c) CH 3 (} CH 2) n CH 2 OCH 2 (CH 2) mCH 3
(N = about 20 to about 200, m = 0 to about 100).

These compounds are derivatives of the compound (a), and the main chain is a linear saturated hydrocarbon. As long as the compound is derived from the compound (a), those other than those shown in the above examples can be used. By using the wax, the toner of the present invention can highly satisfy the fixing property at a low temperature and the anti-offset property at a high temperature.

Among the above compounds, in particular, (a) the formula (a) CH ₃ (CH ₂ ) _n CH ₂ OH (n = about 20 to about 30)
The effect is great by using the wax of which the main component is the high molecular alcohol represented by the formula (1) together with the resin of the present invention. The above wax has good slipperiness, and is particularly excellent in offset resistance.

These waxes are preferably used in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the binder resin. It is also possible to use two or more waxes in combination.

Further, in the present invention, a charge control agent may be contained in the toner as required. For example, a metal complex salt of a monoazo dye, salicylic acid, an alkyl salicylic acid, a metal complex salt of a dialkyl salicylic acid or naphthoic acid, a nigrosine-based compound, an organic quaternary ammonium salt, and the like can be used. In order to obtain the compound, a monoazo metal compound (A
Equation). Further, as a means for further stabilizing the charge, a combination use of two kinds of charge control agents of a monoazo metal compound and an oxycarboxylic acid metal compound (formula B) can be given. The reason for this is that the oxycarboxylic acid-based metal compound appropriately crosslinks the binder resin, prevents contamination of the developing roller, the contact charging member, the electrostatic image holder, and the like, and increases the allowable range for high-temperature offset. Can be On the other hand, since the monoazo metal compound contributes to further stabilization of charging, a toner having more stable characteristics can be obtained. Among the monoazo-based metal compounds, preferred are those represented by Formula (A-2). This is because the azo-based iron complex can be suitably dispersed particularly in a binder having an acid component by an intermolecular interaction.

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The toner of the present invention has environmental stability,
An inorganic fine powder or a hydrophobic inorganic fine powder may be mixed for the purpose of improving charging stability, developability, fluidity, storage stability and the like. For example, it is preferable to use silica fine powder or titanium oxide fine powder alone or in combination.

As the fine silica powder, both a so-called dry method produced by vapor phase oxidation of a silicon halide or a so-called fumed silica and a so-called wet silica produced from water glass or the like can be used. . In the case of fumed silica, a composite fine powder of silica and another metal oxide can be obtained by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the manufacturing process.

Further, the inorganic fine powder is preferably subjected to a hydrophobic treatment. The hydrophobizing treatment is applied by chemically treating with an organic silicon compound or the like which reacts or physically adsorbs with the inorganic fine powder. Examples thereof include a method in which a dry silica fine powder generated by vapor phase oxidation of a silicon halide compound is treated with a silane coupling agent, or treated with a silane coupling agent and simultaneously treated with an organosilicon compound such as silicone oil. Is mentioned.

Examples of the silane coupling agent used in the hydrophobizing treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Examples include disiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane containing a hydroxyl group.

Examples of the organosilicon compound include, for example,
Silicone oil. Preferred silicone oils are those having a viscosity of 30 to 1000 centistokes at 25 ° C., for example, dimethyl silicone oil, methylphenyl silicone oil, α-
Particularly preferred are methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

As the method of treating the silicone oil, for example, the inorganic fine powder treated with the silane coupling agent and the silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the inorganic fine powder serving as a base may be mixed. A method of spraying silicone oil on the body may be used. Alternatively, a method of dissolving or dispersing silicone oil in an appropriate solvent, adding an inorganic fine powder, mixing and removing the solvent may be used.

The toner according to the present invention may contain additives other than those described above, if necessary, and may include a charge auxiliary agent, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent, Fine particles that function as a release agent, a lubricant, an abrasive, or the like. Lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride; or abrasives such as cerium oxide, silicon carbide, and strontium titanate; and fluidity-imparting agents such as titanium oxide and aluminum oxide, especially hydrophobic ones preferable. An anti-caking agent or a conductivity-imparting agent such as, for example, carbon black, zinc oxide, antimony oxide, or tin oxide, or white and black fine particles of opposite polarity can be used in a small amount as a developability improver.

Resin fine particles, inorganic fine powder, or hydrophobic inorganic fine powder mixed with toner are
0.1 to 10 parts by weight relative to parts by weight (more preferably,
0.1 to 5 parts by weight).

To produce the toner according to the present invention, for example, the toner constituent materials are thoroughly mixed by a mixer, then melt-kneaded using a heat kneader such as a heating roll, kneader or extruder, and further cooled and solidified. Post-crushing and classification methods can be used. At this time, a method of controlling the shape of the toner according to the manufacturing apparatus and conditions can be used. For example, the crusher can be driven by mechanical impact or heat.
It is also possible to use means for causing abrasion, peeling or melting on the toner surface to form toner particles having a desired shape.

In the present invention, it is also effective that the developing roller contains at least one of carbon black, graphite, conductive metal and conductive rubber. In particular, those having an elastic layer as a material of the developing roller, for example, natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, isoprene rubber, NBR, etc. are used. It is effective when used in the form of a sponge or the like. It is also possible to provide a magnetic field generating layer, but this is not particularly necessary.

In the present invention 2, a toner supply roller for supplying toner to the developing roller may be provided. Contact and non-contact can be appropriately selected between the two rollers. An AC or DC electric field or an AC + DC electric field may be applied between these two rollers. By providing the toner supply roller, the toner can be charged smoothly, and variations in the toner layer on the developing roller can be eliminated. The material of the toner supply roller is not particularly limited, and a known material such as sponge, rubber, SUS, or a material obtained by coating these materials can be used. In some cases, in addition to the supply roller, a peeling roller having a function of once peeling off toner not used for development from the developing roller can be provided.

In particular, in the present invention, when the conductive layer of the developing roller contains particles having a number average particle diameter of 0.3 to 30 μm, good results are obtained with respect to dispersion uniformity and durability. For example, metals such as copper, nickel, silver, and aluminum, antimony oxide, tin oxide, titanium oxide,
Powders of compounds such as barium titanate and calcium titanate are exemplified. When the number average particle diameter is less than 0.3 μm, the effect of resistance adjustment is weak. When the number average particle diameter is more than 30 μm, it is difficult to obtain sufficient strength of a layer containing the particles, and the resistance is made uniform. It is difficult to carry out the charging, which is likely to cause uneven charging.

Further, it has been found that when the particles contain spherical particles having an inorganic fine powder adhered or fixed to the surface, a result with even higher durability stability can be obtained. Also,
It has been found that when the spherical particles are carbonized on the surface, particularly favorable results can be obtained in durability.

As a method for obtaining conductive spherical particles usable in the present invention, for example, a phenol resin, a naphthalene resin, a furan resin, a xylene resin, a divinylbenzene polymer, a styrene-divinylbenzene copolymer or the like is calcined. A method of carbonization and graphitization; or the surface of these resin particles is coated with a bulk meso fuse pitch by a mechanochemical method, and the coated particles are heat-treated in an oxidizing atmosphere; Examples of the method include graphitization. In addition, a method of incorporating conductive fine particles during polymerization, a method of kneading and dispersing the resin and the conductive fine particles, and then pulverizing, and a method of attaching the conductive fine particles by mechanical impact can also be used.

It is also effective to disperse these in a coating agent for the elastic layer, and generally known resins can be used as the coating resin. For example, phenol resin, epoxy resin, polyamide resin, acrylic resin, polyester resin, silicone resin, fluorine resin, styrene resin, melamine resin, polyimide resin and the like can be mentioned. The reason for this is that the effect is obtained with a small amount of addition compared to conventionally used graphite, and that it is excellent in durability because it is hard to be scraped.

It is also possible to use together with other fine particles, for example, furnace black, lamp black, thermal black, acetylene black, channel black, titanium oxide, tin oxide, zinc oxide, aluminum oxide, graphite and the like. .

Further, according to the study of the present inventors, in order to further exert the effect of the present invention, the developing roller contains a silicone resin having a high releasing effect, so that the charging ability is not impaired and the durability is improved. Has been found to be able to have. In addition, these silicone resins have an alkyl group as a substituent,
It is effective to contain at least one substituent selected from an aryl group, a modified alkyl group, a modified aryl group, a phenyl group, a modified phenyl group, an amino group and an imino group.

Further, due to the unevenness of the developing roller surface,
The effect of improving toner transportability has been found,
Ra is desirably 8.5 μm or less, and more preferably 0.1 to 6.5. If the surface roughness is less than 0.1 μm, the toner transportability may be reduced and a sufficient image density may not be obtained. If the surface roughness is more than 8.5 μm, toner that cannot be sufficiently charged due to an excessively large toner transport force may be obtained. Occurs.

It is also possible to provide blades upstream and downstream of the rotation of the developing roller with respect to the developing position. Furthermore, it is also possible to apply a voltage to these members. In the supply roller, it is also possible to combine the functions of stripping and supply. Further, it is preferable to provide a toner layer regulating member upstream of the developing section. This toner layer regulating member may be a plate-shaped member, or a rotating roller may be used. It is also preferable to charge the toner with the toner layer regulating member.

In the present invention, a contact-type charging system can be used as a charging means for charging the electrostatic image holder, and the charging member may be a fibrous brush, an elastic roller, a belt, a film, or a magnetic member. A roller in which magnetic powder is present around the roller is used, and the surface of the electrostatic image holder is directly charged while the contact band electrons are in direct contact with the electrostatic image holder.

As a desirable mode for charging the electrostatic image holder, a primary charging roller is, for example, an EPDM.
(Ethylene propylene diene rubber) A rubber roller (diameter 12 mm, contact pressure 49 N / m (50 g / cm)) whose resistance is controlled to a medium resistance by coating the roller with a nylon resin.
Can be used in contact with the electrostatic image holder.

Examples of the conductive fine particles used for resistance adjustment include metals such as copper, nickel, iron, aluminum, gold, and silver, and iron oxide, ferrite, zinc oxide, tin oxide, antimony oxide, and titanium oxide. Examples include metal oxides and conductive powders such as carbon black. The conductive fine particles used in the present invention have a volume resistance of 1 × 1.
0 ⁷ [Omega] cm is desirable following ones, the particle size is less desirable 1 [mu] m.

It is desirable that the surface roughness Ra of the charging roller is 0.1 or more and 8.0 or less. More preferably,
It is preferably 0.2 or more and 6.0 or less. When Ra is less than 0.1, the frictional force between the electrostatic image holder and the electrostatic roller increases, and the deterioration of both the electrostatic image holder and the charging roller is accelerated. Further, when Ra exceeds 8.0, even if an elastic roller is used, the line of electric force at the time of charging tends to concentrate on the convex portion of the charging roller due to the difference in pressure. It is easy to generate a hole-shaped deterioration site.

FIG. 1 is a schematic explanatory view of an image forming apparatus applied to the present invention.

The OPC photosensitive drum 1, which is an electrostatic image holding member, rotates in the direction of the arrow, and is uniformly primary charged by the charger 4. Next, the image portions are exposed by the exposure devices 5 and 6, and an electrostatic latent image is formed. The electrostatic image holder (photosensitive drum) 1 and the toner layer on the developing roller (toner carrier) 9 in FIG. 1 are set to be in contact with each other, and a DC bias is applied to the toner carrier 9 by bias applying means. Then, the image portion is developed to form a toner image on the photosensitive drum. It is also possible to use an AC bias.

The obtained toner image is transferred onto a transfer material (recording material) by a transfer roller (transfer means) 15. Although a cleaner having a cleaning blade for cleaning the toner remaining on the surface of the photoreceptor can be used, it can be collected during development in the developing unit without using it. On the other hand, the transfer material separated from the photosensitive drum 1 is supplied to a heat fixing device, and the toner image on the transfer material is heat-fixed to the transfer material. Image formation is performed by repeating the above steps. Further, an image can be formed by attaching a sponge toner application roller (not shown) to the back surface of the developing roller in the toner container 7.

In the present invention, the toner image formed on the electrostatic image holding member can be transferred to a transfer material (recording material) via an intermediate transfer member.

FIG. 8 shows an example in which the intermediate transfer member 21 is used in the present invention.

In the image forming apparatus shown in FIG. 8, toner 8 is introduced into developing device 7, and a plurality of developing devices 7 may be used for each color of toner.

In the image forming apparatus shown in FIG.
The toner image developed on the electrostatic image holder 1 is primary-transferred to the intermediate transfer member 21 in contact with the surface of the electrostatic image holder 1 by applying a transfer voltage, as in the case of the image forming apparatus shown in FIG. The toner image transferred to the intermediate transfer body 21 is transferred by a transfer roller (transfer unit) 25 to a transfer material (recording material).
The image is secondarily transferred onto the image. As for the toner image transferred onto the transfer material, the transfer material is supplied to the heat fixing device in the same manner as in the case of the image forming apparatus shown in FIG. 1, and the toner image on the transfer material is heated and fixed on the transfer material.

As the intermediate transfer member 21, a general material can be used. Preferably, the voltage applied to the transfer member 25 can be reduced by setting the volume specific resistance of the transfer material 26 smaller than the volume specific resistance of the intermediate transfer body 21, so that a good toner An image can be formed, and the winding of the transfer material 26 around the intermediate transfer body 21 can be prevented. Further, the intermediate transfer member 21
Is preferably in the range of 10 to 40 degrees. The intermediate transfer member 21 may be provided with an intermediate transfer member cleaner 22 having a cleaning member 23 for contacting the intermediate transfer member 21 and removing the toner remaining on the intermediate transfer member 21 after the transfer to the transfer material. .

Hereinafter, the contact transfer step applicable to the image forming method of the present invention will be specifically described.

In the contact transfer step, the developed image is electrostatically transferred to the transfer material while the transfer means is in contact with the electrostatic image carrier or the intermediate transfer body via the transfer material. The pressure is preferably a linear pressure of 3 g / cm or more, more preferably 20 g / cm or more.

As the transfer means in the contact transfer step, an apparatus having a transfer roller or a transfer belt is used. In the transfer roller, the conductive elastic layer is preferably made of an elastic material having a volume resistance of about 10 ⁶ to 10 ¹⁰ Ωcm, such as urethane or EPDM in which a conductive material such as carbon is dispersed, but is not particularly limited.

Further, in the present invention, it has been found that a good image can be obtained even in a DC charging or DC developing system in which charging and development are performed only by DC without using an AC electric field. The reason is that there is little aggregation between toners,
This is presumed to be because more uniform charging was achieved. Further, by using the toner of the present invention, contamination to the charging member and the like is small, and unlike the conventional image forming conditions, a high-definition image can be obtained for a long time.

When a cleaning member is used in the present invention, a blade, a roller, a fur brush, a magnetic brush, or the like can be used as the cleaning member. Further, two or more of these cleaning members may be used in combination.

Among these, blade cleaning is preferred. In blade cleaning, urethane rubber, silicone rubber, or resin having elasticity is used as a blade, or a blade made of metal or the like with a tip-shaped resin held in the tip is moved forward or backward with respect to the moving direction of the photoconductor. It is known as abutted or pressed. At this time, the contact pressure of the blade against the photoreceptor is preferably 10 g / cm or more as a linear pressure, and more preferably 15 to
50 g / cm. When the contact pressure is less than 10 g / cm in linear pressure, it is difficult to remove even the ultrafine powder component from the photoreceptor, and the ultrafine powder component slips through the blade, so that a fine scratch is formed on the tip of the blade. For example, the cleaning effect on other toner particles may be impaired, and image stains may easily occur. When fine particles such as inorganic oxides are added to the toner for the purpose of imparting fluidity or the like, the contact pressure is preferably set to 15 g / cm or more because these particles tend to promote the toner particles to slip through. Is desirable. Further, if the contact pressure is larger than 50 g / cm, the durability of the blade itself becomes a problem, and if the blade is used for a long time, an image may be stained due to defective cleaning. Is preferred. Further, a known method such as a mag brush cleaning method, a fur brush cleaning method, or a roller cleaning method may be combined with the blade cleaning method.

In some cases, 1) the transfer residual toner present on the electrostatic image holder after the transfer step is set to the opposite polarity so that the electrostatic image holder does not come into contact with the transfer material until the next transfer step. When it corresponds to a paper portion, the transfer residual toner can be returned to the developing roller via the electrostatic image holding member, or 2) a toner reuse process can be provided from a transfer residual toner collection container using a pipe with a built-in screw. is there.

Further, in the present invention, it is also possible to adopt a cleaner-less structure without using a cleaner, because the amount of transfer residual toner is small.

As the photoconductive substance of the electrophotographic photosensitive member used in the present invention, known substances can be used. For example,
An organic photoconductive substance can be mentioned, and a function-separated type in which a charge generation layer and a charge transport layer are laminated is particularly preferably used.

The photoreceptor used at this time includes a photoconductive material using an inorganic photoconductive material such as selenium, cadmium sulfide, and zinc oxide, a photoconductive polymer represented by poly-N-vinylcarbazole, And low-molecular organic photoconductive materials such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole.

Of these, a photoreceptor using an organic photoconductive substance has relatively advantages in that it is relatively inexpensive and can be produced by coating, so that a photoreceptor with extremely high productivity can be provided at a low cost. . Further, a combination of such an organic photoconductive substance with various dyes and pigments can also be used. It is also possible to provide a protective layer on the photoconductive layer in order to realize high durability. For example, in JP-A-2-93543, a protective layer which is cured by irradiation with radiation is used.
In JP-A-146047, a polycarbonate resin containing a charge transport material is used. In JP-A-3-17655, a metal or fine metal powder and a bisphenol A type polycarbonate resin are used. In JP-A-3-103741, a curable epoxy resin is used. It has been proposed. These are intended to prevent damage to the photosensitive layer and the like by covering a photosensitive layer or a necessary member for exhibiting a function as a photosensitive member. It is also preferable that these surface layers contain a fluorine compound or a silicon compound having a high releasing effect.

Next, the measuring method in the present invention will be described.

1) Method of Measuring Toner Shape Photographs of the toner are taken at an appropriate magnification using a scanning electron microscope. At this time, for the same particle, several images are taken of a screen in which the electron beam is vertically applied to the toner on the sample table and a screen in which the electron beam is horizontally applied, and a rectangular parallelepiped circumscribing one particle is drawn. Further, a, b, and c are set so that each side of the rectangular parallelepiped satisfies a ≧ b ≧ c, and a, b, and c are measured. The above operation is randomly performed for 100 particles, and the average of b / a and c / a is obtained.

2) Method of Measuring Toner Charge Amount 2.5 g of toner and a carrier (EF manufactured by Powder Tech Co., Ltd.)
V-200 / 300) 47.5 g was weighed in a 50 cm ³ polyethylene container, and the temperature was 21 to 25 ° C. and the humidity was 55 to 6
Leave for 2 days in a 3% environment. This is covered and shaken with a turbula mixer for 240 seconds, about 0.5 g is weighed, and the triboelectric charge is measured by a suction method. FIG. 4 shows a charge amount measuring apparatus according to the present invention. A sample is placed in a metal measuring container 22 having a conductive screen 23 of 500 mesh (which can be appropriately selected to a size that does not allow the passage of carrier particles) at the bottom, and a metal lid is placed. Next, suction is performed through the suction port 27 in the suction device 21 (at least the portion in contact with the measurement container 22 is an insulator), and the air volume control valve 26 is adjusted to adjust the pressure of the vacuum gauge 25 to 250 mmH ₂ O. Suction is performed for 1 minute in this state. The voltage of the electrometer at this time is defined as V (volt). Here, 28 is a capacitor whose capacity is C (μ
F). The amount of charge obtained from this is divided by the amount of toner (g) removed by suction to obtain the triboelectric charge amount (mC / k
g).

3) Molecular Weight Distribution Measurement Method In the present invention, the molecular weight distribution is measured by GPC (gel permeation chromatography) under the following conditions.

<GPC Measurement Conditions> Apparatus: GPC-150C (manufactured by Waters) Column: KF801 to 7 (manufactured by SHOdex) Temperature: 40 ° C. Solvent: THF (tetrahydrofuran) Flow rate: 1.0 ml / min. Sample: 0.1 m of a sample having a concentration of 0.05 to 0.6% by weight
l Injection Measurement is performed under the above conditions, and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

4) Method of measuring glass transition point Tg In the present invention, the glass transition point Tg of the resin is measured under the following conditions using a differential thermal analyzer (DSC measuring apparatus), DSC-7 (manufactured by PerkinElmer). did.

Sample: 5 to 20 mg, preferably 10 mg Temperature curve: Heating I (20 ° C. → 180 ° C., heating rate 10 ° C./min.) Cooling I (180 ° C. → 10 ° C., cooling rate 10 ° C./min. ) Temperature rise II (10 ° C. → 180 ° C., temperature rise rate 10 ° C./min.) The Tg measured at the temperature rise II is defined as a measured value.

Measurement method: A sample is placed in an aluminum pan, and an empty aluminum pan is used as a reference. The intersection of the line of the midpoint of the baseline before and after the endothermic peak appeared and the differential heat curve was defined as the glass transition point Tg.

5) Method for Measuring Component Having Absorption Caloric Peak at 45-115 ° C. in the Toner In the present invention, the component having an absorption calorie peak at 45-115 ° C. contained in the toner is a differential thermal analyzer (DSC) Measuring device), DSC
-7 (manufactured by PerkinElmer) under the following conditions.

Sample: 5 to 20 mg, preferably 10 mg Temperature curve: Heating I (20 ° C. → 180 ° C., heating rate 10 ° C./min.) Cooling I (180 ° C. → 10 ° C., cooling rate 10 ° C./min. ) Temperature rise II (10 ° C. → 180 ° C., temperature rise rate 10 ° C./min.) Measurement method: A sample is placed in an aluminum pan, and an empty aluminum pan is used as a reference. Among the peaks measured at the temperature rise II, the endothermic peak appearing at 45 to 115 ° C. is determined based on the baseline before and after the endothermic peak appears, and used as the measured value.

6) Method of Measuring Acid Value of Toner The acid value of the toner of the present invention was measured by a potentiometric titration method.

Apparatus: AT-400 manufactured by Kyoto Electronics Industry

7) Method of Measuring Softening Point The softening point of the present invention is measured by the ring and ball method (JIS K2406).

A test piece is melted and poured into a brass ring having an inner diameter of 15.9 mm and a depth of 6.4 mm, and is fitted by punching, molding, or the like. A steel ball of 3.5 ± 0.5 g is placed and placed in a liquid bath, and the liquid temperature is raised at 5 ° C./min. As the test piece softens, the steel ball descends, and the temperature at which the steel ball comes into contact with the plate surface 25.4 mm below the lower end of the ring is defined as the softening point.

8) Melt Index (MI) Measurement Method The melt index (MI) of the present invention is measured according to JIS K7.
Using the apparatus described in No. 210, measurement is performed by the manual cutting method under the following measurement conditions. At this time, the measured value is converted into a 10-minute value.

Measurement temperature: 125 ° C. Load: 10 kg Sample filling amount: 5 to 10 g

9) Method of Measuring Particle Size Distribution of Toner The average particle size and particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co., Ltd.). Using a counter TA-II type (manufactured by Coulter), an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC) were connected. % NaCl aqueous solution is prepared.
For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and the measurement sample is further added to 2 to 20 ml.
Add mg. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number of toner particles of 2 μm or more were measured using a 100 μm aperture as the aperture by the Coulter Counter TA-II. The volume distribution and number distribution were calculated. then,
Volume-based volume average particle diameter (Dv: median value of each channel is a representative value of a channel) and volume variation coefficient (Sv) obtained from the volume distribution according to the present invention, number-based length obtained from the number distribution Average particle size (D1) and length variation coefficient (S
1) and the weight-based coarse powder amount (1
2.7 μm or more), and the number-based fine powder amount (3.17 μm or less) determined from the number distribution.

10) Method of Measuring Center Line Average Roughness (Ra) of Developing Roller and Charging Roller Based on JIS surface roughness (B0601), a surf coder SE-3300 manufactured by Kosaka Laboratories was used. Two points in the circumferential direction = 6 points were measured, and the average was taken.

11) Method of Measuring Charge Amount (qe, qc) of Toner on Developing Roller The toner suction portion is brought close to the developing roller, and the toner on the developing roller is suctioned to measure the charge amount.

The measurement of the charge amount on the developing roller was performed using a Faraday cage shown in a perspective view in FIG. The inside (the right side of the figure) was depressurized so that the toner on the developing roller was sucked, and a toner filter 33 was provided to collect the toner. The charge amount Q / M (qe, qc) on the developing roller was calculated from the weight M of the collected toner and the charge Q directly measured by a coulomb meter.

[0171]

Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on embodiments. However, this does not limit the embodiment of the present invention. Parts in the examples are parts by weight.

Example 1 Toner Production Example 1 Styrene-n-butyl acrylate-monobutyl maleate copolymer (resin 1) 100 parts Carbon black (colorant) 5 parts Charge control agent Compound 1 shown in C-1 Part D-1 Compound 2 parts Low molecular weight polypropylene 4 parts After thoroughly mixing the above materials with a Henschel mixer, 13 parts
The mixture was mixed well with an extruder set at 0 ° C., cooled, coarsely pulverized by a cutter mill, and finely pulverized by a mechanical pulverizer. Thereafter, the particles were classified by an air classifier to obtain black toner particles.

To 100 parts of the obtained black fine powder, 1.1 parts of colloidal silica was added and mixed with a Henschel mixer to obtain Toner 1. At this time, by changing the conditions of the pulverization to the classification step, a toner having a shape and a particle size as shown in Table 3 was obtained.

[0174]

Embedded image

[0175]

Embedded image

Preparation of Developing Roller 1 As conductive spherical particles, 100 parts of spherical phenolic resin particles of 10 μm were coated with a 3 μm particle size by using a raikai machine (automatic mortar).
m or less coal-based bulk mesophase pitch powder uniformly coated, and then thermally stabilized in an oxidizing atmosphere, and then calcined at 2600 ° C. to obtain graphitized spherical conductive carbon particles. I got

Resol type phenol resin solution (containing 50% methanol) 200 parts Graphite having a number average particle diameter of 6.1 μm 45 parts Conductive carbon black 5 parts Isopropyl alcohol 130 parts Zirconia beads having a diameter of 1 mm are added to the above materials as media particles. Then, 10 parts of the above-mentioned conductive carbon particles were added to 380 parts of a dispersion obtained by a sand mill and dispersed to obtain a coating liquid.

Using this coating liquid, a spray method was used.
A conductive resin coating was formed on a roller made of urethane rubber containing 15% of carbon black to produce a developing roller 1.

Image Output Test Using the toner 1 and the developing roller 1 in a configuration shown in Table 5, in a low-temperature and low-humidity environment (15 ° C./10% RH)
Under a normal temperature and normal humidity environment (23 ° C./60% RH), an image was formed under a high temperature and high humidity environment (32.5 ° C./80% RH).
Table 6 shows the results of the image formation test.

In this example, a commercially available laser beam printer LBP-PX (manufactured by Canon) was used under the following conditions.

FIG. 1 is a schematic explanatory view of an image forming apparatus applied to the present invention.

The OPC photosensitive drum 1, which is an electrostatic image holding member, rotates in the direction of the arrow, and is uniformly charged by the charger 4 so that the dark portion potential (Vd) becomes -600V.
Next, the image portions are exposed by the exposure devices 5 and 6,
An electrostatic latent image having a bright portion potential (Vl) of -150 V is formed. The electrostatic image holder (photosensitive drum) 1 and the toner layer on the developing roller (toner carrier) 9 in FIG. 1 are set to be in contact with each other, and a DC bias (Vdc = −400 V) is applied to the toner by a bias applying unit. The image portion was developed while being applied to the body 9 to form a toner image on the photosensitive drum. In the case where an AC bias is used, (f
= 1700 Hz, Vpp = 1200 V).

The obtained toner image is transferred onto a transfer material by a transfer roller 15. The cleaner for cleaning the toner remaining on the photoreceptor surface was removed. On the other hand, the transfer material separated from the photosensitive drum 1 is subjected to a heat fixing process by a heat fixing device in order to fix a toner image on the transfer material. Image formation is performed by repeating the above steps. An image was formed by attaching a sponge toner application roller to the back of the developing roller in the toner container 7.

In Table 5, “roller charging” refers to a conductive silicon roller having a surface coated with a fluororesin.

"Contact" in Table 5 indicates the developing method in which the toner on the developing roller shown in FIGS. 1 and 2 is in contact with the electrostatic image holder, and "Non-contact" means that in FIG. 5 shows a developing method in which the toner on the developing roller and the electrostatic image holder are not in contact with each other.

Under the above setting conditions, a reprint-out test was performed on 10,000 continuous sheets while supplying the toner according to the present invention and the comparative toner at a print-out speed of 8 sheets / min. The items were evaluated.

(Evaluation of Printout Image) (1) Image Density An ordinary density paper (75 g / m ² ) for a copying machine was evaluated for the degree of maintaining the image density at the beginning and end of durability.
The image density was measured by using a “Macbeth reflection densitometer” (manufactured by Macbeth Co., Ltd.) to measure the relative density of the white background portion of the original density 0.00 with respect to the printout image. ◎ (excellent): 1.40 or more, ○ (good): 1.35 or more and less than 1.40, Δ (acceptable): 1.00 or more and less than 1.35, × (impossible): less than 1.00

(2) Image Quality (Resolution) A thin line image was printed out and its resolution was evaluated using a loupe. (Number of discriminable lines, average value of 10 places) （(very good): 7 (lines / mm) or more, （(good): 6 (lines / mm) or more, 7 (lines / m)
m), △ (acceptable): 5 (lines / mm) or more and 6 (lines / mm)
Less than, × (impossible): less than 5 (line / mm)

(3) Image fog The fog density (%) was calculated from the relationship between the whiteness of the white background portion of the printout image measured by “Reflectometer” (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper. Image fog was evaluated. The worst values in the three environments were compared.

(4) Fixing Property The fixing property was evaluated by applying a load of 50 g / cm ² , rubbing the fixed image with soft thin paper, and decreasing the image density before and after rubbing (%). ◎ (excellent): less than 5%, 〇 (good): 5% or more and less than 10%, Δ (acceptable): 10% or more and less than 20%, × (impossible): 20% or more

(5) Preservation of Toner 10 g of the toner was placed in a 50 ml polyethylene cup and placed in a constant temperature bath at 50 ° C. for 3 days to evaluate the blocking resistance of the toner at that time. ◎ (excellent): unchanged, ○ (good): slightly poor fluidity, △ (acceptable): slightly solidified, but practical, × (impossible): blocked, impractical

(6) Contamination of Charging Roller After the completion of the printout test, the effect on the durability of the charging roller was evaluated based on the state of adhesion of foreign substances to the surface of the charging roller and the results of image evaluation. ◎ (very good): almost no deposits were observed, and the image quality was comparable to the initial stage. ○ (good): almost no deposits were observed, and the change in image quality was extremely small. △ (acceptable): attached The level of kimono is extremely small and the image has no problem. × (impossible): There are many deposits and image defects occur.

(7) Developing Roller Soil After the printout test was completed, the state of adhesion of the residual toner to the developing roller surface and the effect on the printout image were examined. ◎ (very good): almost no deposits were observed, and the image quality was comparable to the initial stage. ○ (good): almost no deposits were observed, and the change in image quality was extremely small. △ (acceptable): attached Very few kimonos and no problem with the image. × (impossible): Many sticks and image unevenness

(8) Stains on the electrostatic image holder The damage of the surface of the photosensitive drum and the occurrence of sticking of the residual toner and the influence on the printout image were visually evaluated. ◎ (very good): almost no deposits were observed, and the image quality was comparable to the initial stage. Δ (good): almost no deposits were observed, and the change in image quality was extremely small. △ (acceptable): attached The level of kimono is extremely small and the image has no problem. × (impossible): There are many deposits and image defects occur

(9) Fixing Device Staining The fixing state of the residual toner on the surface of the fixing roller after the completion of the printout test was visually evaluated. ◎ (excellent): no deposits occurred, ○ (good): hardly generated, △ (acceptable): practical, × (impossible): impractical

<Examples 2 to 16 and Comparative Examples 1 to 4> The physical properties of the resins were prepared as shown in Table 1, and the toners were prepared as shown in Tables 2 and 3. The developing roller shown in Table 4 was used.

The procedure was carried out in the same manner as in Example 1 except that the developing conditions were changed as shown in Table 5, and the results shown in Tables 6 and 7 were obtained. (C-2) in Table 2 is a compound having the following structure.

[0198]

Embedded image

[0199]

[Table 1]

[0200]

[Table 2]

[0201]

[Table 3]

[0202]

[Table 4]

[0203]

[Table 5]

[0204]

[Table 6]

[0205]

[Table 7]

<Example 17> Toner Production Example 15 Styrene-n-butyl acrylate-monobutyl maleate copolymer (Resin 4) 100 parts Carbon black (colorant) 5 parts Charge control agent Compound 1 shown in C-1 Part D-1 Compound 2 Part W-1 Compound 4 After the above materials were mixed well with a Henschel mixer, 13
The mixture was mixed well with an extruder set at 0 ° C., cooled, coarsely pulverized by a cutter mill, and finely pulverized by a mechanical pulverizer. Thereafter, the particles were classified by an air classifier to obtain black toner particles.

To 100 parts of the obtained black fine powder, 1.1 parts of colloidal silica was added and mixed with a Henschel mixer to obtain Toner 15. At this time, by changing the conditions of the pulverization to the classification process, a toner having a shape and a particle size as shown in Table 10 was obtained. This toner had an endothermic peak at 92 ° C.

Preparation of Developing Roller 2 A phenol resin layer containing graphite and conductive carbon black was formed on a urethane rubber roller containing 15% of carbon black to prepare a developing roller 2.

Using the toner 15 and the developing roller 2, an image forming test was performed as shown in Table 12.
The configuration shown in Fig. 1 is used in a low temperature and low humidity environment (15 ° C / 10% R
H), image formation was performed in a normal temperature and normal humidity environment (23 ° C./60% RH), and in a high temperature and high humidity environment (32.5 ° C./80% RH). Table 13 shows the results of the image formation test.

In the present embodiment, a commercially available laser beam printer LBP-PX (manufactured by Canon) was modified.
Modified and used under the same conditions as above.

Then, a reprint-out test was performed on 10,000 continuous sheets while supplying the toner according to the present invention and the comparative toner at a print-out speed of 8 sheets / min. Items were evaluated.

<Examples 18 to 43 and Comparative Examples 5 to 7>
The physical properties of the resin were manufactured as shown in Table 8, and the toners were manufactured as shown in Tables 9, 10 and 11.

The same procedures as in Example 17 were carried out except that the developing conditions were changed as shown in Table 12, and the results shown in Tables 13 and 14 were obtained.

[0214]

[Table 8]

[0215]

[Table 9]

W-1: CH ₃ (CH ₂ ) _n CH ₂ OH; Mw
= 870, n = 47 W-2: Styrene-modified wax W-3: Low-melting paraffin wax W-4: Polypropylene wax

[0219]

[Table 10]

[0218]

[Table 11]

[0219]

[Table 12]

[0220]

[Table 13]

[0221]

[Table 14]

Example 44 Toner Production Example 38 Styrene-n-butyl acrylate-monobutyl maleate copolymer (Resin 9) 100 parts Carbon black (coloring agent) 7 parts Charge control agent Compound 1 shown in C-1 Compound shown in Part D-1 2 parts After thoroughly mixing the above ingredients with a Henschel mixer, 13
The mixture was mixed well with an extruder set at 0 ° C., cooled, coarsely pulverized by a cutter mill, and finely pulverized by a mechanical pulverizer. Thereafter, the particles were classified by an air classifier to obtain black toner particles.

To 100 parts of the obtained black fine powder, 1.1 parts of colloidal silica was added and mixed with a Henschel mixer to obtain a toner 38. At this time, the toner having the shape and particle size as shown in Table 17 was obtained by changing the conditions from the pulverization to the classification step.

Preparation of Developing Roller 3 As conductive spherical particles, 100 parts of 10 μm spherical phenol resin particles were added to a 3 μm particle size using a raikai machine (automatic mortar).
m or less coal-based bulk mesophase pitch powder uniformly coated, and then thermally stabilized in an oxidizing atmosphere, and then calcined at 2600 ° C. to obtain graphitized spherical conductive carbon particles. I got

Resol type phenol resin solution (containing 50% methanol) 200 parts Graphite having a number average particle diameter of 6.1 μm 45 parts Conductive carbon black 5 parts Isopropyl alcohol 130 parts Zirconia beads having a diameter of 1 mm are added as media particles to the above materials. Then, 10 parts of the above-mentioned conductive carbon particles were added to 380 parts of a dispersion obtained by a sand mill and dispersed to obtain a coating liquid.

Using this coating solution, a spray method
A phenol resin layer containing graphite and conductive carbon is formed on a portion of the urethane rubber roller containing 15% of carbon black except for an end portion thereof, and further,
Both ends of the developing roller were coated with a phenol resin layer having a width of about 2 cm, reducing the amount of conductive carbon to 3 parts and containing an amino-modified silicone resin, to produce a developing roller 3.

[0227] Using the image output test of the toner 38 and the developing roller 3, Table 19
The configuration shown in Fig. 1 is used in a low temperature and low humidity environment (15 ° C / 10% R
H), image formation was performed in a normal temperature and normal humidity environment (23 ° C./60% RH), and in a high temperature and high humidity environment (32.5 ° C./80% RH). Table 20 shows the results of the image formation test.

In this embodiment, a commercially available laser beam printer LBP-PX (manufactured by Canon) was modified.
Modified and used under the same conditions as above.

Then, a reprint-out test was performed on 10,000 continuous sheets while supplying the toner according to the present invention and the comparative toner at a print-out speed of 8 sheets / minute, and the obtained images were evaluated for the following items. .

(Evaluation of Printout Image) Among the evaluation items in Example 1, the image density, image quality, image fog, fixing property, charging roller stain, developing roller stain and electrostatic image holder stain were examined. The following items were also evaluated.

(1) In-machine Contamination The in-machine contamination state (under the developing roller) after the 10,000-sheet printout test was evaluated. ◎ (excellent): no toner was observed, （(good): toner was slightly present, Δ (acceptable): slightly deposited, × (impossible): large toner leakage

(2) Image Uniformity The difference between the image density at the center and the edge of the printout image was evaluated for the solid black image density and the halftone image density. ：: no difference in density (0.00 to 0.01), 、: slight difference in density (0.02 to 0.03), Δ: difference in density (0.04 to 0.05), ×: density Large difference (0.06 or more)

Preparation of Developing Roller 4 A phenol resin layer containing graphite, conductive carbon black, and an acryl-modified silicone resin was formed on the portion of the urethane rubber roller containing 18% carbon black except for the ends. Further, both ends of the developing roller were thickly coated with the same material with a width of about 2 cm using the same material, thereby producing a developing roller 4.

Preparation of Developing Roller 5 A phenol resin layer containing graphite and conductive carbon black was formed on a portion of the urethane rubber roller containing 18% of carbon black except for an end portion of the roller.
In addition, the width of about 2 cm on both ends of the developing roller,
Coating was performed with the same resin layer by further increasing the viscosity of the coating liquid, and a developing roller 5 was produced.

Preparation of Developing Roller 6 A phenolic resin layer containing graphite and conductive carbon black was formed on the portion of the urethane rubber roller containing 18% carbon black except for the ends of the roller.
In addition, the width of about 2 cm on both ends of the developing roller,
The coating was performed by increasing the viscosity of the coating solution with a phenol resin layer containing an imide-modified silicone-based resin (the thickness of the coating layer was made thinner than the central portion), and a developing roller 6 was produced.

Preparation of Developing Roller 7 A phenol resin layer containing graphite and conductive carbon black was formed on a urethane rubber roller containing 15% of carbon black.
Was prepared.

<Examples 45 to 57 and Comparative Examples 8 to 13>
> The physical properties of the resin were manufactured as shown in Table 15, and the toners were manufactured as shown in Tables 16 and 17. The developing roller shown in Table 18 was used.

The procedure was carried out in the same manner as in Example 44 except that the developing conditions were changed as shown in Table 19, and the results shown in Tables 20 and 21 were obtained.

[0239]

[Table 15]

[0240]

[Table 16]

[0241]

[Table 17]

[0242]

[Table 18]

[0243]

[Table 19]

[0244]

[Table 20]

[0245]

[Table 21]

[0246]

According to the present invention, high-definition images can be formed, and durability stability, environmental stability (high-temperature high-humidity characteristics, standing characteristics) and excellent fixing characteristics can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an example of an image forming apparatus suitable for forming an image according to the present invention.

FIG. 2 is a schematic view showing an example of an image forming apparatus suitable for forming an image according to the present invention.

FIG. 3 is a schematic diagram illustrating an example of an image forming apparatus that performs image formation excluded from the present invention.

FIG. 4 is a schematic view showing a measuring device used for measuring the charge amount of the toner in the present invention.

FIG. 5 is a schematic diagram showing a measuring device used to measure the charge amounts qc and qe of the toner on the developing roller according to the third embodiment.

FIG. 6 is a diagram illustrating a relationship between a charge amount and a shape of a toner according to the first and second embodiments of the present invention.

FIG. 7 is a diagram illustrating a relationship between a charge amount and a shape of a toner according to a third exemplary embodiment of the present invention.

FIG. 8 is a schematic diagram showing an example of another image forming apparatus suitable for forming an image according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum (latent image carrier) 4 charging roller 5 exposure device 7 developing device 8 toner 9 developing roller 13 blade 14 developing bias applying means 15 transfer roller 16 transfer material (recording material) 21 intermediate transfer member 22 intermediate transfer member cleaner 23 Cleaning Member 25 Transfer Roller (Transfer Means) 26 Transfer Material (Recording Material) 31 Toner Suction Direction on Developing Roller 32 Insulating Member 33 Toner Filter

Claims (40)

[Claims] An electrostatic latent image is formed using a developing device having at least a developing roller that rotates while supporting a toner on a surface thereof and develops the electrostatic latent image formed on the electrostatic image holder with the toner. In the image forming method for developing, the developing device develops the toner on a developing roller that adheres and transports a developer to a surface during development while contacting the toner on a developing roller provided oppositely. The weight average particle diameter of the toner is 10 μm or less, and the content of 12.7 μm or more in the particle size distribution is 20% by weight or less. A so that a>b> c or a> b = c or a = b> c or a = b = c
When b and c are defined, the average of b / a is 0.4 to 0.5.
98. An image forming method having a shape having an average c / a of 0.3 to 0.95. 2. A weight average particle size D4 (μm) of the toner.
Is 3.5 ≦ D4 ≦ 9.5, and the relationship with the abundance ratio N (number%) of the particles having a particle size of 3.17 μm or less in the number particle size distribution is as follows: 35−D4 × 5 ≦ N ≦ 180−D4 A particle size distribution satisfying × 25.
2. The image forming method according to 1., 3. The toner according to claim 1, wherein the binder resin has an acid value of 0.1 mg.
KOH / g or more and 40 mgKOH / g or less, and
The image forming method according to claim 1, wherein the softening temperature of the binder resin is 140 ° C. or more and 165 ° C. or less, and the Tg of the binder resin is 54 ° C. or more and 65 ° C. or less. 4. The developing roller includes a conductive layer, and the conductive layer has a number average particle diameter of at least 0.3 to 3 with a binder resin.
4. The image forming method according to claim 1, comprising particles having a particle size of 0 μm and a true density of 3 g / cm ³ or less. 5. The image forming method according to claim 4, wherein the particles are spherical particles having an inorganic fine powder adhered or fixed on the surface. 6. The image forming method according to claim 4, wherein the surface of the particles is carbonized. 7. When a rectangular parallelepiped circumscribing the toner is imagined, each side of the rectangular parallelepiped is defined as a>b> c or a> b.
= C or a = b> c or a = b = c, when a, b and c are defined, the average of b / a is 0.7
The image forming method according to any one of claims 1 to 6, wherein the image forming apparatus has a shape in which the average of c / a is 0.5 to 0.85 and the average of c / a is 0.5 to 0.85. 8. The binder resin of the toner has a weight average molecular weight (Mw) in a range of 150,000 to 300,000, and a value of (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 8 to 6.
5, and the melt index (MI) is 2-3.
8. The image forming method according to claim 1, wherein the value is within a range of 0. 9. An absolute value | Q | of a charge amount of the toner is 6 m.
When C / kg or more and 48 mC / kg or less, and one imaginary cuboid circumscribing the toner, one side of each cuboid is a>b> c or a> b = c or a = b> c
Alternatively, when a, b, and c are defined such that a = b = c, −8 × c / a + 16 ≦ | Q | ≦ −28 × c / a
The image forming method according to any one of claims 1 to 8, wherein +56 is satisfied. 10. The image forming method according to claim 1, wherein the toner contains a monoazo metal compound. 11. The image forming method according to claim 10, wherein the toner contains a monoazo iron complex compound. 12. The image forming method according to claim 1, wherein said toner contains a monoazo metal compound and an oxycarboxylic acid metal compound. 13. The image forming method according to claim 1, wherein the developing device does not use a waste toner container. 14. An electrostatic latent image is formed by using a developing device having at least a developing roller which rotates while carrying toner on its surface and develops the electrostatic latent image formed on the electrostatic image holder with the toner. In the image forming method for developing, the developing device develops the toner on a developing roller that adheres and transports a developer to a surface during development while contacting the toner on a developing roller provided oppositely. A component having a weight average particle size of 10 μm or less, a content of 12.7 μm or more in the particle size distribution of 20% by weight or less, and having a heat absorption peak at 45 to 115 ° C. in the toner; An image forming method comprising: 15. The image forming method according to claim 14, wherein the component having a heat absorption peak at 45 to 115 ° C. is a higher alcohol. 16. A weight average particle diameter D4 (μm) of the toner.
Is 3.5 ≦ D4 ≦ 9.5, and the relationship with the abundance ratio N (number%) of the particles having a particle size of 3.17 μm or less in the number particle size distribution is as follows: 35−D4 × 5 ≦ N ≦ 180−D4 A particle size distribution satisfying × 25.
16. The image forming method according to 4 or 15. 17. The component having a heat absorption peak at 45 to 115 ° C. contains a low molecular weight wax, and the low molecular weight wax has the following general formula RY (R: hydrocarbon, Y: hydroxyl group, carboxyl group, alkyl 17. A compound represented by the formula: ether group, ester group or sulfonyl group), and having a weight average molecular weight (Mw) of 3,000 or less as determined by gel permeation chromatography. An image forming method according to any one of the above. 18. The image according to claim 17, wherein the low molecular weight wax contains a high molecular weight alcohol represented by CH ₃ (CH ₂ ) _n OH (n = 20 to 300) as a main component. Forming method. 19. When the acid value of the binder resin of the toner is A and the position of the maximum endothermic peak among components contained in the toner and having a heat absorption peak at 45 to 115 ° C. is B ° C. The image forming method according to claim 14, wherein the image satisfies 55 ≦ B−2 × A ≦ 105. 20. The binder resin of the toner having an acid value of 0.1 m
gKOH / g or more and 40 mgKOH / g or less, the softening temperature of the binder resin is 140 ° C or more and 165 ° C or less, and the Tg of the binder resin is 54 ° C or more and 65 ° C or less. The image forming method according to claim 14. 21. The binder resin of the toner having a weight average molecular weight (Mw) in the range of 120,000 to 600,000 and a value of (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 8 to 6.
21. The image forming method according to claim 14, wherein MI is 5 and MI is in a range of 2 to 30. 22. When a rectangular parallelepiped circumscribing the toner is imagined, each side of the rectangular parallelepiped is a>b> c or a>
When a, b, and c are defined so that b = c or a = b> c or a = b = c, the average of b / a is equal to 0.
70-0.92 and the average of c / a is 0.50-0.85
3. The structure according to claim 1, wherein
2. The image forming method according to any one of 1. 23. The absolute value | Q | of the charge amount of the toner is 6
mC / kg or more and 48 mC / kg or less, and one side of each of the rectangular solids imagining a rectangular solid circumscribing the toner is a>b> c or a> b = c or a = b>
When a, b, and c are defined so that c or a = b = c, −8 × c / a + 16 ≦ | Q | ≦ −28 × c /
23. It satisfies a + 56.
The image forming method according to any one of the above. 24. The image forming method according to claim 14, wherein the toner contains a monoazo metal compound. 25. The image forming method according to claim 14, wherein the toner contains a monoazo iron complex compound. 26. The image forming method according to claim 24, wherein the toner contains a monoazo metal compound and an oxycarboxylic acid metal compound. 27. The image forming method according to claim 14, wherein said developing device does not use a waste toner container. 28. A developing device having a developing roller having at least a developing roller which rotates while supporting toner on the surface and develops the electrostatic latent image formed on the electrostatic image holding member with the toner, to form the electrostatic latent image. In the image forming method for developing, the developing device develops the toner on a developing roller that adheres and transports a developer to a surface during development while contacting the toner on a developing roller provided oppositely. The absolute value of the charge amount is larger at the end of the developing roller than at the center of the developing roller, and the weight average particle size of the toner is 10 μm or less, and the toner has a particle size distribution of 12.7 μm or more. When the amount is 20% by weight or less, and one side of each of the rectangular parallelepipeds is imagined as a rectangular solid circumscribing the toner, a>b> c or a> b = c or a = b> c or a = b = c A, so that
When b and c are defined, the average of b / a is 0.4 to 0.5.
98. An image forming method, wherein the toner has a shape having an average c / a of 0.3 to 0.95, and the relationship between the shape of the toner and the charge amount satisfies the following expression. c / a × 12 + 3 ≦ | Q | ≦ c / a × 16 + 41 (| Q |: absolute value of toner charge amount) 29. A weight average particle diameter D4 (μm) of the toner.
Is 3.5 ≦ D4 ≦ 9.5, and the relationship with the abundance ratio N (number%) of the particles having a particle size of 3.17 μm or less in the number particle size distribution is as follows: 35−D4 × 5 ≦ N ≦ 180−D4 3. It has a particle size distribution satisfying × 25.
9. The image forming method according to 8. 30. The binder resin of the toner having an acid value of 0.1 m
gKOH / g or more and 40 mgKOH / g or less, the softening temperature of the binder resin is 140 ° C or more and 165 ° C or less, and the Tg of the binder resin is 54 ° C or more and 65 ° C or less. The image forming method according to claim 28 or 29, wherein 31. The charge amount of the toner at the center of the developing roller is qc, and the charge amount of the toner at the end of the developing roller is qe.
31. The image forming method according to claim 28, wherein the following expression is satisfied. 0.4 ≦ | qe−qc | ≦ 14.5 32. The charge amount of the toner at the center of the developing roller is qc, and the charge amount of the toner at the end of the developing roller is qe.
31. The image forming method according to claim 28, wherein the following expression is satisfied. 0.8 ≦ | qe−qc | ≦ 5.6 33. When a rectangular parallelepiped circumscribing the toner is imagined, each side of the rectangular parallelepiped is defined as a>b> c or a>
When a, b, and c are defined so that b = c or a = b> c or a = b = c, the average of b / a is equal to 0.
The image forming method according to any one of claims 28 to 32, wherein the shape has a shape of 75 to 0.9 and an average of c / a is 0.75 to 0.9. 34. The toner according to claim 34, wherein the binder resin has a weight average molecular weight (Mw) in the range of 150,000 to 300,000, and a value of (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 8 to 6.
5, and the melt index (MI) is 2-3.
35. The range of 0 to 35.
The image forming method according to any one of the above. 35. The image forming method according to claim 28, wherein said toner contains a monoazo metal compound. 36. The image forming method according to claim 35, wherein the toner contains a monoazo iron complex compound. 37. The image forming method according to claim 28, wherein the toner contains a monoazo metal compound and an oxycarboxylic acid metal compound. 38. The image forming method according to claim 28, wherein said developing roller includes a conductive layer. 39. The conductive layer has at least a binder resin and a number average particle diameter of 0.3 to 30 μm and a true density of 3
The image forming method according to claim 38, characterized in that it consists of a g / cm ³ or less of the particles. 40. The image forming method according to claim 28, wherein said developing device does not use a waste toner container.