JPH025070A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To improve cleanability and to prevent melting or filming of a toner to the surface of a photosensitive body by mixing >=2 kinds of resins which have the peak values of the mol.wt. distribution within the same range, are nearly the same in the form of the mol.wt. distribution and are different in acid value as a binder resin. CONSTITUTION:A coloring agent is dispersed in the mixture composed of the resin which has respectively >=1 peak values of the low mol.wt. distribution in 1X10<3>-5X10<4>-5X10<7> ranges and has <=13 acid value and the resin which has respectively >=1 peak values of the mol.wt. distribution in the same ranges as the above-mentioned ranges and has >=30 acid value. The charge of the toner remaining and sticking on the photosensitive body in a developing stage is, therefore, rapidly attenuated in the cleaning stage and the Coulomb force of the electrostatic latent image and the toner at the time of the cleaning is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a toner for developing electrostatic images, and more particularly to a toner having improved cleaning properties and moisture resistance, and excellent fixing properties.

(Prior art and its problems) Conventionally, in a copying machine using an electrophotographic method, an electrostatic latent image formed on a photoreceptor having a photosensitive layer containing an inorganic or organic photoconductive substance is processed by a dry developing method. Various powder toners containing colorants, binder resins, etc. are used for visualization.

In the electrophotographic method, an electrostatic latent image formed on the photoreceptor by charging and exposure to light is developed with the I-toner, and the toner image formed on the electrostatic latent image is transferred to a support such as transfer paper. At the same time, the electrostatic latent image is visualized by fixing the toner image on the support by a fixing means such as a heating roller or a pressure roller. Further, after the toner image is transferred to the support, the remaining toner on the photoreceptor is scraped off by a cleaning blade in order to clean the toner remaining on the photoreceptor. In addition, as a photoreceptor that has high sensitivity in the visible light region, has excellent durability and abrasion resistance, and is compatible with high-speed copying, we have developed a photoreceptor (hereinafter referred to as a-3i photoreceptor) that has a photosensitive layer made of amorphous silicon. ) has been proposed. The surface potential of this photoreceptor largely depends on the film thickness of the photoreceptor layer, and when the film thickness is increased in order to increase the surface potential, crystal growth becomes significant and the uniformity of the surface of the photoreceptor decreases. Therefore, in the case of a-3i bad exposure, the thickness of the photosensitive layer should be adjusted within a range that does not impair the uniformity of the photoconductor surface.
For example, although the film thickness of the photosensitive layer is usually set to about 5 to 60 μm, even with such a film thickness, not only is it easy for unevenness such as pinballs to occur in the photosensitive layer, but also a-
3i photons are generally used with low surface potentials and are highly affected by environmental humidity. In view of the above points, a toner containing a specific polyester having a glass transition point of 50 to 70°C and exhibiting low humidity properties has been proposed as a toner for the a-3i photoreceptor exhibiting a low surface potential. (Japanese Unexamined Patent Publication No. 61-28477).

Although the above-mentioned toner has excellent moisture resistance and triboelectric charging properties, when applied to A-3I photoreceptor with a thicker photoreceptor layer, the toner fuses to the photoreceptor because the surface of the photoreceptor layer is particularly uneven. Then, it gradually grows, resulting in so-called toner filming.

More specifically, the adhesion force between the photoreceptor and toner is greatly influenced by the Coulomb force due to the surface potential of the electrostatic latent image on the photoreceptor and the amount of charge on the toner. mainly depends on the amount of electricity of the toner. Therefore, in an image forming apparatus using the electrophotographic method, when the cleaning process is repeatedly performed, pressure from the cleaning blade and frictional heat between the surface of the photoreceptor and the cleaning blade are applied to the toner adhered to the photoreceptor due to Coulomb force. Coupled with the non-uniformity of the a-3i photoreceptor surface and the large amount of charge of the toner, the cleaning properties of the toner deteriorate, and the toner fuses to the photoreceptor.
This not only shortens the life of the toner and thus the developer, but also causes black spots of the toner on the copied image, deteriorating the quality of the copied image. Furthermore, since the surface potential of the a-3i photosensitive material is low, so-called image blurring is likely to occur particularly in the dark areas of a copied image (and it is difficult to form a clear copied image).

Furthermore, in order to improve the cleaning properties of the toner, an a-3i toner for bad sensitivity has been proposed, which is made by adding fine powder of strontium titanate to l-toner containing polyester (Japanese Patent Laid-Open No. 61-278861). Public bulletin). Although this toner has improved cleaning properties, there is a problem in that the cleaning properties of the toners are not sufficient in toners containing resins other than polyester.

In addition, a-3i photoreceptor is often used in high-speed copying machines because of its durability and abrasion resistance, and toner for aSi photoreceptors is required to be capable of rapid fixing in addition to the above-mentioned cleaning properties. It is necessary for the toner to melt rapidly at a low temperature, penetrate and adhere to the transfer material, and maintain good fixing properties such that the molten toner exhibits cohesive properties and does not transfer to the fixing roller.

(Objective of the Invention) The present invention has been made in view of the problems and demands of the prior art described above, and has excellent cleaning properties even when using the A-3i photoreceptor, and can be applied to the surface of the photoreceptor. A toner for electrostatic image development that does not cause toner fusion or filming, and therefore does not cause smudges on copied images, and is capable of rapid fixing, suitable for high-speed copying, and capable of forming clear images over a long period of time. The purpose is to provide

(Means for solving the problem) One or more peak values of the molecular weight distribution are set in the ranges of 1 x 103 to 5 x 104 and 5 XIO' to 5 XIO'.
For electrostatic image development, in which a colorant is dispersed in a mixture of a resin having an acid value of 13 or less, and a resin having an acid value of 30 or more, each having one or more peak values in the molecular weight distribution in the same range as above. The purpose of the invention is achieved by the toner.

(Function) The toner of the present invention uses, as a binder resin, a mixture of two or more resins having different acid values, which have peak values of molecular weight distribution in the same range, have almost the same form of molecular weight distribution, and have different acid values. Features. As mentioned above, in the toner cleaning process, the charge of the toner remaining on the photoconductor during the developing process is quickly attenuated in the cleaning process, and the Coulomb force between the electrostatic latent image and the toner during cleaning is reduced ( This is necessary in order to prevent fusion of 1-hener to the photoreceptor and 1-hener filming.

Through experiments and the like, the present inventors have found that a toner having a relaxation time of 5 to 20 mm-5 ec at a frequency of 100 kHz is useful in reducing the adhesion force of the toner during cleaning. Therefore, in order to suppress humidity dependence and an abnormal increase in toner charge amount, we adjusted the toner relaxation time by changing the blending amount of carbon black as a colorant in a resin with an acid value of 20 or less. Although satisfactory results were obtained regarding cleaning properties, the toner mixed with the carbon blank required to obtain the desired relaxation time significantly increased the viscosity of the molten toner during fixing, resulting in poor fixing properties. Especially when the toner penetrates into the transfer material in a short period of time during high-speed copying, the fixing rate decreases and fixing failure occurs.

Therefore, the present inventors further investigated and found that when an appropriate amount of resin with an acid value of 30 or more is blended with a resin with an acid value of 13 or less,
By adjusting the amount of carbon black, the relaxation time of the toner was reduced to within the range of 5 to 20 mm-5 ec, and the viscosity of the molten toner was not increased, resulting in excellent developability and cleaning performance, as well as excellent fixing performance. It was discovered that a 1-ner can be obtained.

Furthermore, a feature of the present invention is that the molecular weight distribution of each resin having a different acid value is determined by the peak value of the molecular weight distribution determined by Körpermien Yos chromatography (GPC).
1 or more in the ranges of O3~5x104 and 5XIO'~5XlO7, and the two resins have substantially the same molecular weight distribution.

In other words, one of the peaks in the molecular weight distribution is IXl, 03-5
By being within the range of XIO', fixing properties and cleaning properties are further improved. The peak of the molecular weight distribution is 1×10
If it is not in the range of 3 to 5
Polymers that do not fall in the range of ' to 5

Toner made of resin that has peaks in the two molecular weight regions mentioned above has high hardness and a moderately low melt index value, so it does not easily adhere to the photoreceptor, has good cleaning properties, and can be fixed at low temperatures. The toner melts quickly and the cohesive force of the toner is maintained during melting.
Excellent fixing properties can be obtained. In addition, although the present invention is a mixture of two types of resin, each has a similar molecular weight distribution form, so the melt mixture is uniformly mixed, and the toner produced is different from the characteristics of each particle. becomes less.

As for the mixing ratio of the resins having different acid values, it is generally preferable that the weight ratio of the resin having an acid value of 30 or more to the resin having an acid value of 13 or less is 10=1 to 1:1, particularly 8 to 2. If a large amount of resin with an acid value of 30 or more is added beyond the above range, the moisture resistance of the toner will deteriorate and image deterioration at high temperatures will become significant.

Furthermore, if the blending ratio of the resin with an acid value of 30 or more is less than the above range, there will be no effect in reducing the relaxation time.
Cleanability deteriorates.

Mixing within the above range results in excellent moisture resistance and short relaxation time and good cleaning properties.

The above resins include styrene polymers, acrylic polymers, styrene-acrylic polymers, polyethylene, chlorinated polyethylene, polypropylene, olefin polymers such as ionomers, polyvinyl chloride, polyester,
Examples include various polymers such as polyamide, polyurethane, epoxy resin, diallylphthale-1 resin, silicone resin, ketone resin, polyvinyl butyral resin, phenol resin, lysine-modified phenol resin, xylene resin, rosin-modified maleic acid resin, and rosin ester.

Among these, styrene polymers, acrylic polymers, or styrene-acrylic polymers, particularly styrene-acrylic polymers, are preferred because they are easy to control in terms of crushability and molecular weight distribution.

The above-mentioned polymers preferably have a softening point of generally 50 to 200°C, particularly 70°C to 170°C.

In addition, in order to control the charge of the toner, the above-mentioned toner may contain a charge control agent, such as an oil-soluble dye such as nigrosine dye, oil black, or soubiron black, or manganese such as nantenic acid, salicylic acid, octylic acid, fatty acid, or resin acid. , iron, cobalt, nickel, lead, zinc, cerium, calcium,
Those containing 0.1 to 5% by weight of metal soaps such as metal salts, metal-containing azo dyes, pyrimidine compounds, alkyl salicylic acid metal chelates, etc. are preferred.

In addition, the above-mentioned toner may contain offset preventing agents, such as various waxes such as low molecular weight polypropylene, low molecular weight polyethylene, and paraffin wax, and olefin monomers having 4 or more carbon atoms, in order to prevent the toner from adhering to the fixing roller. It is preferable to contain 0.5 to 15% by weight of a low molecular weight olefin polymer, fatty acid amide, silicone oil, etc.

Furthermore, although the present invention is suitable for toners that use carbon black as a colorant, it can also be applied to toners that use known colorants that are responsible for the conductivity and coloring properties of toners.

These colorants include Lamp Black, Chrome Yellow, Hanzai Elo, Henjijin Yellow, Suren Yellow G, -)-Norin Yellow, Permanent Orange GTR, Pyrazolone Orange, Hulcan Orange, Watch Young Red, Permanent Ret, and Brilliant Carmine 3B. , Brilliant Carmine 6B, Dupont Oil Red, Pyrazolone Red, Lysol Red, Rhodamine B Lake, Lakelet, Rose Hengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Loride, Futa l: I Cyanine Blue, Tsuku I Cocyanine Green , Malachite Clean Oxale = 1, pigments such as C,1,5olvent Ye
low 60, C, l5olvent Red
Examples include oil-soluble dyes such as 27, C, 1,5olvent Blue 35, and the like. These colorants may be used individually or in a mixture of two or more.

These colorants are generally 3 to 20% by weight per toner.
In particular, 6 to 15% by weight is preferably used.

The toner having the above composition may have an appropriate hardness, but in order to prevent deformation due to stress during cleaning, prevent toner from adhering to the photoreceptor, and improve cleaning properties, the toner has a Vickers hardness. Those having 12 or more are preferred.

When the Vickers hardness is less than 12, the toner tends to fuse to the photoreceptor during cleaning.

Further, when the toner is a magnetic toner, a magnetic substance can be contained together with or in place of the colorant. The above-mentioned magnetic material may be any material that exhibits magnetism or is magnetizable; for example, ferrite, magnetite, iron, cobalt, nickel, manganese, or other ferromagnetic metals or alloys, or these metals. Examples include compounds containing the following. These magnetic substances have an average particle size of 0.1 to 1 μm, and when mixed together, the amount of these magnetic substances is generally 5 to 70 parts by weight, preferably 20 to 50 parts by weight, per 100 parts by weight of resin. Parts by weight are used.

Further, the toner having the above composition may have an appropriate tart index value, but in order to prevent the toner from fusing to the photoreceptor due to heat during curing, etc.
It is preferable that the melt index at a temperature of 150° C. and a load of 2160 g is 5 to 20 g/10 minutes. If the melt index is less than 5 g/10 minutes, the toner will be too hard and will not have sufficient fixing properties, and if it exceeds 20 g/l 0 minutes, the toner will be deformed during cleaning and will tend to fuse, resulting in insufficient cleaning properties. .

The toner preferably has an average particle size of generally 3 to 30 μm, particularly 5 to 20 μm.

In addition, in order to reduce the electrostatic adhesion of the toner to the photoconductor and further improve the cleaning performance of the toner, positively chargeable fine powder and negatively chargeable fine powder are added to the powder toner containing the above-mentioned materials. Preferably, it is added externally. Examples of the positively chargeable fine powder include talc, kaolin, barium sulfate, aluminum silicate, calcium silicate,
It may be titanium oxide, calcium carbonate, antimony trioxide, magnesium oxide, zinc oxide, zirconium oxide, etc., aluminum oxide, pressurized fine powder treated with silicone oil having amino groups, especially silicone having amino groups. Hydrophobic silica treated with oil,
Preferably, those selected from the group consisting of acrylic resins. In addition, the positively charged fine powder may have an appropriate particle size within a range that does not damage the photoreceptor, but the average particle size of the acrylic resin fine powder is 100 to 250 μm, and the average particle size is 100 to 250 μm. Preferably, the average particle size is about 5 to 100 μm, particularly about 10 to 30 μm.

Moreover, as a preferable negatively chargeable fine powder, for example, hydrophobic silica is exemplified. The negatively chargeable fine powder may have an appropriate particle size, but preferably has an average particle size of about 5 to 100 μm, particularly about 10 to 30 μm.

Further, the weight ratio of positively chargeable fine powder to negatively chargeable fine powder can be used at an appropriate ratio depending on the particle size of each fine powder. ), especially 1:5
It is preferable to use it in a ratio of 2.5:1 to 2.5:1 (parts by weight).

If the ratio of the positively chargeable fine powder to the negatively chargeable fine powder exceeds the above range, it will be difficult to suppress adhesion of toner to the photoreceptor and improve cleaning performance.

The fine powder consisting of the positively chargeable fine powder and the negatively chargeable fine powder having the above proportions can be added in an appropriate amount to the powder toner, but it ranges from 0.01 to 1 part by weight per 100 parts by weight of the powder. Preferably, it is added. Addition amount of fine powder is 0
If the amount is less than 1 part by weight, it is difficult to improve the cleaning properties of the (-ner), and if it exceeds 1 part by weight, the photoreceptor is likely to be damaged.

Note that when the above-mentioned positively charged voltage fine powder and negatively charged fine powder are added to powder toner, the positively charged fine powder and the negatively charged fine powder are combined by Coulomb force. It is thought that the adhesive force between the toner and the photoreceptor is weakened, and the cleaning properties of the toner are improved. Furthermore, the addition of the fine powder improves the fluidity of the toner or developer, improving the charging characteristics and image characteristics of the toner.

In addition to protecting the photoreceptor, fatty acid metal salts such as zinc stearate, aluminum stearate, etc. may be added externally to prevent deterioration of developer properties. The above fatty acid metal salt is generally o, ooi per 100 parts by weight of toner.
It is preferable to add 1 to 1 part by weight, particularly 0.005 to 0.5 part by weight.

Further, in order to improve the fluidity of the toner, the surface of the toner may be treated with a compound having low surface tension such as a silane coupling agent, silicone, or a fluorine compound.

The toner of the present invention is useful as either a one-component developer or a two-component developer. - When used as a component developer, the toner containing the above magnetic material alone is used as a developer,
When used as a two-component developer, an uncoated carrier such as glass beads, oxidized or unoxidized iron powder, or ferrite, or a magnetic material such as iron, nickel, cobalt, or ferrite is combined with an acrylic polymer or a fluorine-based polymer. A coated carrier coated with a polymer such as polyester is used, and usually 5
It has a particle size of 0 to 2000 μm.

Further, when a developer consisting of the above toner and carrier is used, the toner concentration is 2 to 15% by weight.

Further, as the electrostatic latent image carrier, selenium, selenium-
Photoreceptors having an inorganic photoconductive layer such as tellurium, zinc oxide, cadmium sulfide, amorphous silicon, etc., photoreceptors having an organic photoconductive layer containing a charge generating substance and a charge transporting substance, electrostatic recording paper, etc. Can be used. Further, the toner for developing an electrostatic latent image can be used by a conventionally customary developing method, for example.
- When the developer is a component developer, it is developed by a bristle brush method, a magnetic flage method, or a powder cloud development method, and when it is a two-component developer, it is developed by a cascade development method, a magnetic brush development method, or the like.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

(Example 1) As a binder resin, the molecular weight distribution curve determined by GPC, as shown in FIG. 1(a), was 9. 3. Peak value (molecular weight, 1.3 XIO') in the region of OXIO2 to 3.9 x 10'.
9 XIO'~1. 75 parts by weight of a styrene-acrylic copolymer (manufactured by Mitsui Toatsu Chemical Co., Ltd.) having a peak value (molecular weight, 6.2 Xl05) in the region of IXIO3 and an acid value of 13, as shown in FIG. In the molecular weight distribution curve by GPC shown in 4. The peak value (molecular weight, 1.4 XIO') in the region of OXIO2 to 3.8 XIO' and 3.8 Xl
The peak value (molecular weight, 2
．． 6 x 105) and an acid value of 30 (manufactured by Mitsui Toatsu Chemical Co., Ltd.) and carbon black (Monarch) as a coloring agent.

700, manufactured by Cabot Corporation) 6 parts by weight, polypropylene as an anti-offset agent (trade name: Viscol 550P,
2 parts by weight (manufactured by Sanyo Chemical Co., Ltd.), and a negative polar dye (Spiron Black T RH1 manufactured by Hodogaya Chemical Co., Ltd., trade name) as a charge control agent. After melting and dispersing 0 parts by weight using a heated roll mill, the particles are coarsely pulverized and classified to obtain an average particle size of 5 to 2.
A powder toner of 0 μm was prepared.

To 10 parts by weight of I~Luna obtained above, 25% by weight of polymethyl methacrylate fine powder as positively chargeable fine powder and hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil) as negatively chargeable fine powder were added. 0.4 part by weight of fine powder consisting of 75% by weight of R972) was added and mixed. In addition, the above toner 4
．． A component developer was prepared by uniformly mixing 5 parts by weight of ferrite carrier and 95.5 parts by weight of a ferrite carrier having an average particle size of 50 to 120 μm in a ball mill.

In addition to examining the characteristics of the toner obtained above, a copying machine (manufactured by Sanda Kogyo Co., Ltd., DC=55
Image output and 60,000-sheet durability test (at 25°C, 160% normal temperature and humidity, and at 35°C, 185% high temperature and high humidity) using a modified 85-inch machine, 55 A4 horizontal sheets per minute). The image characteristics etc. were investigated. In addition, the surface temperature of the fixing roller was adjusted from 110°C to 5'C in the high-speed copying machine mentioned above and a low-speed copying machine capable of copying 20 sheets per minute (manufactured by Sanda Kogyo Co., Ltd., model DC-2055). One by one, the transfer paper with the transferred image is passed through and fixed, and the adhesive tape is pressed against the formed fixed image and then peeled off. The fixing rate was determined by measuring the image density of the subsequent fixed image using a reflection densitometer (manufactured by Tokyo Juishoku Co., Ltd.), and the temperature at which the fixing rate was 90% or more was determined.

The results of each test are shown below.

Toner relaxation time (at 100KHz) is 16mm-5e
c, and the copied image was clear. In addition, in a printing durability test, at room temperature and humidity, good images were continuously obtained through 60,000 sheets without toner filming on the photoreceptor drum or black streaks on the copied images. . Furthermore, under high temperature and high humidity conditions, the cleaning performance decreased slightly after 40,000 sheets were printed, but this was not a problem.

Regarding fixing performance, the fixing rate on a 55 sheets/minute machine was 90.
% or more is 170'C, and 20 sheets/
The minimum temperature at which the fixation rate in the separator is 90% or more is 16
0°C, and it was confirmed that the image was fixed quickly at a low temperature even during high-speed copying.

(Example 2) A toner was prepared in the same manner as in Example 1 except that 80 parts by weight of the resin with an acid value of 3 and 20 parts by weight of the resin with an acid value of 30 were used.

The relaxation time of this toner was 19 mm-sec, and the copied image was clear. In the printing durability test, good images were obtained through 60,000 sheets even at room temperature and humidity as well as at high temperature and high humidity.
No black streaks were observed on the image. Regarding fixing performance, the lowest temperature at which the fixing rate is 90% or more in a 55 sheets/minute machine is 170°C, and the lowest temperature at which the fixing rate is 90% or more in a 20 sheets/minute machine is 160°C. It was confirmed that even during high-speed copying, the image was fixed quickly at low temperatures.

(Example 3) A toner was prepared in the same manner as in Example 1 except that 60 parts by weight of the resin having an acid value of 13 and 40 parts by weight of the resin having an acid value of 30 were used.

The relaxation time of this toner is 11. The copying time was 5 mm-sec, and the copied image was clear. In the printing durability test, the
Under normal humidity, good image formation could be performed through 60,000 copies without toner filming on the photoreceptor or black streaks on the copied images.

At the same temperature and high humidity, the cleaning performance decreased after 30,000 sheets were printed, but this was not a problem. Further, image fogging was observed after 50,000 sheets were printed, but it was within an appropriate range. In addition, the fixability is 55
The minimum temperature is 70°C for a fixation rate of 90% or more in a sheet/minute machine, and a fixation rate of 90% in a 20 sheets/minute machine.
% or more was 160° C., and it was confirmed that fixing was rapid at low temperatures.

(Comparative Example 1) In the same manner as in Example 1, except that 100 parts by weight of the resin having an acid value of 30 was used, and the resin having an acid value of 13 was not used, samples 1 to 1 were obtained.

The relaxation time of this toner was 9 mm-sec, and a clear image was obtained. In the printing durability test, at room temperature and humidity, the image characteristics and cleaning properties were good through 60,000 sheets, and good images were obtained without toner filming on the photoreceptor or black streaks on the copied image. It was done. Under high temperature and high humidity conditions, after the number of sheets exceeded 10,000, image fogging became severe and images lacked sharpness. Furthermore, the deterioration progressed with continued copying, and when the number of copies exceeded 40,000, toner scattering became severe and the degree of defective images became even more severe. Regarding fixing performance, the fixing rate on a 55 sheets/minute machine was 90.
% or higher is 170°C, and the lowest temperature at which the fixing rate is 90% or higher in a 20 sheets/minute machine is 160°C.
°C, and it was confirmed that the film was fixed quickly at low temperatures.

(Comparative Example 2) A toner was prepared in the same manner as in Example 1 except that 100 parts by weight of the resin having an acid value of 13 was used and the amount of carbon black added was 15 parts by weight.

The relaxation time of this toner was 15 mm, sec, and a clear image was obtained. In the printing durability test, it was possible to form good images without toner filming on the photoreceptor or black streaks on the copied images through 60,000 copies at room temperature and humidity. Further, even under high temperature and high humidity conditions, after the number of sheets exceeded 40,000 sheets, although there was a slight decrease in cleaning performance, it was not a problem and satisfactory results were obtained.

Regarding fixing performance, the lowest temperature at which the fixing rate is 90% or higher in a 55 sheets/minute machine is 190°C, and the lowest temperature at which the fixing rate is 90% or higher in a 20 sheets/minute machine is 190°C.
75°C, which increases the minimum fixing temperature especially in high-speed copying machines, requires considerable thermal energy to obtain a fixing rate of 90% or more, and requires lowering the viscosity of the molten toner. Understood.

(Comparative Example 3) A toner was prepared in the same manner as in Example 1 except that 100 parts by weight of the resin having an acid value of 13 was used and the amount of carbon blank added was 6 parts by weight.

The relaxation time of this toner was 30 mm-sec, and a clear image was obtained. In printing durability tests, toner filming occurred on the photoreceptor drum and black streaks appeared on images after 10,000 sheets were printed at room temperature and under high temperature and high humidity conditions. When copying work was continued, the black streaks grew and image deterioration progressed. 2 more
After the number of images exceeded 5,000, the entire image became blackish.

Regarding fixing performance, the lowest temperature at which the fixing rate is 90% or higher in a 55 sheets/minute machine is 170°C, and the lowest temperature at which the fixing rate is 90% or higher in a 20 sheets/minute machine is 170°C.
The temperature was 60°C, and the fixing properties were good.

(Comparative Example 4) A toner was prepared in Example 1 using 92 parts by weight of the resin having an acid value of 13 and 8 parts by weight of the resin having an acid value of 30.

The relaxation time of this toner was 23 m5 ec, and the copied image was clear. In printing durability tests, toner filming occurred on the photoreceptor drum after printing more than 15,000 sheets at room temperature and under high temperature and high humidity, and by the time the sheets exceeded 20,000 sheets, images began to deteriorate. Black streaks occurred. When copying work was continued, the black streaks grew and image deterioration progressed.

Furthermore, after more than 30,000 images were taken, the sharpness of the images began to deteriorate, and the images became completely blackish.

Regarding fixing performance, the lowest temperature at which the fixing rate is 90% or higher in a 55 sheets/minute machine is 170°C, and the lowest temperature at which the fixing rate is 90% or higher in a 20 sheets/minute machine is 170°C.
60"C, and it was confirmed that it was fixed quickly at low temperature.

(Comparative Example 5) As a binder resin, the molecular weight distribution curve determined by GPC shown in FIG. A peak (Ii! (molecular weight, 1.3
The amount of carbon black added was 13 parts by weight to 100 parts by weight of a styrene-acrylic copolymer (manufactured by Mitsui Toatsu Co., Ltd.) having a molecular weight of 2°7 x 105) and an acid value of 17, and the rest was Example 1. A toner was prepared in the same manner.

The relaxation time of this toner is 18. A clear copy image was obtained in 5 m sec. In the printing durability test, it was possible to form a good image without toner filming on the photoreceptor or black streaks on the copied image through 60,000 sheets at room temperature. Furthermore, under high temperature and high humidity conditions, a slight decrease in cleaning performance was observed after 20,000 sheets were printed. Furthermore, after 40,000 copies were printed, image fogging occurred and the images lacked brightness. As for fixing performance, the lowest temperature at which the fixing rate is 90% or more in a 55 sheets/minute machine is 190'C, and the lowest temperature at which the fixing rate is 90% or more in a 20 sheets/minute machine is 170'C. In copying machines, the minimum fixing temperature has increased to 90
It takes a lot of energy to achieve a retention rate of more than %,
It has been found that it is necessary to reduce the viscosity of the fused toner.

The results of the above Examples and Comparative Examples are shown in Table-1. In the table, parts represent parts by weight.

(Hereinafter, blank space) (Effects of the Invention) According to the present invention, a toner with a relaxation time that provides good cleaning performance can be obtained without adding a large amount of carbon black, and it is possible to prevent the toner from fusing and filming on the photoreceptor. It is possible to form a clear image without causing toner black spots or image deletion on the copied image. Furthermore, since the toner of the present invention has excellent environmental resistance and good melting properties, it can be quickly fixed at low temperatures in a high-speed copying machine even under adverse environments, and can form clear copied images.

[Brief explanation of the drawing]

FIGS. 1(a), 1(b) and 2nd are diagrams showing the molecular weight distribution of the binder resins of Examples and Comparative Examples by gel permeation chromatography.

Claims (2)

[Claims] (1) The peak value of the molecular weight distribution is 1 x 10^3 to 5 x 10
A resin with an acid value of 13 or less that has one or more acid values in the range of ^4 and 5 x 10^4 to 5 x 10^7, and an acid value that has one or more peak values of the molecular weight distribution in the same range as the above range. A toner for developing an electrostatic image, in which a colorant is dispersed in a mixture with a resin having a particle size of 30 or more. (2) Electrostatic image development according to claim 1, characterized in that the mixing ratio of the resin having an acid value of 13 or less and the resin having an acid value of 30 or more is 1:1 to 10:1. toner.