JP2002182465A - Image forming method and device, and one-component and two-component developer used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner free from being stuck to or granulated on a developer carrier, internal walls of a developer carrying path and a developer storage part with which developer directly contacts, and also free from image irregularity, a black stripe and fogging due to the above phenomenon, and to provided an image forming method and an image forming device using the toner. SOLUTION: In this image forming method, the temperature of the developer carrying path and the developer storage part in the image forming device is made equal to or lower than the glass transition temperature of toner resin constituting developer, and the surface roughness Rz1 of the developer carrier is set to 1 to 50 μm, and the surface roughness Rz1 and Sm1 of the developer carrier and toner number average particle size of developer (dt) satisfy the following relation: Sm1/Rz1>=2 and Rz1>dt/4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming method and an image forming apparatus used for a copying machine, a printer, and the like, and a one-component or two-component developer used for the same.

[0002]

2. Description of the Related Art At present, in an image forming apparatus used for a copying machine, a printer or the like, an electrostatic latent image developing system mainly using an electrophotographic method is very often used.

[0003] The reasons for this are that the performance is stable even during long-term use with high speed and high image quality, and that color images can be formed. However, the level of performance required for the electrostatic latent image development system is high, and it is increasing year by year, and research and development for satisfying the demand are being actively conducted.

The electrophotographic image forming method of the Carlson method, which is a typical example of the electrostatic latent image developing method, will be described. After uniformly charging an electrophotographic photosensitive member, the charge is erased imagewise by exposure. An electrostatic latent image is formed, the electrostatic latent image is developed and visualized with toner, and then the toner is transferred to a recording medium such as paper (also referred to as a recording material, a transfer material, an image support, etc.) and then fixed. To complete the image formation. In recent years, not only technical studies for each of these steps but also inventions having configurations in which techniques of these several steps are appropriately combined are increasing.

[0005] The most important issue in these studies is to further improve the image quality, but despite the development trends described above, sufficient results have not yet been achieved.

The conventionally used pulverized toner has an irregular shape and a wide particle size distribution, and therefore has a wide charge amount distribution. There is a limit in improving the reproducibility of dot shapes and fine lines and the sharpness of edge portions. However, it has been difficult to meet the recent demand for higher image quality.

On the other hand, the polymerized toner produced by the polymerization method has a uniform shape and particle size distribution, exhibits stable development and transfer characteristics, and is clearly an effective means for achieving high image quality. It has come. However, if the particle size or volume is reduced for higher image quality, the heat capacity and mechanical strength of the toner itself are reduced, and the toner is broken or fused or adhered in the developer transport path or the storage portion, and image fogging is caused. Or transfer failure or increase in the torque of the transfer system or packing.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned problems and to stably obtain high-quality images.

That is, an object of the present invention is to provide a developer carrier which is in direct contact with a developer, which is a major problem in the development of an image forming method and an image forming apparatus capable of obtaining a high-quality and stable copy image for a long period of time. Provided is a toner which does not cause image fusion, black streaks, and fogging based on toner fusion to the developer transport path and the inner wall of the developer accommodating portion and granulation there, and an image forming method and an image forming apparatus using the same. It is in.

[0010]

As a result of intensive studies by the inventors, it has been found that the object of the present invention can be attained by adopting one of the following constitutions.

[1] The electrostatic latent image formed on the electrostatic latent image carrier is developed by using a developer layer carried on the developer carrier to be visualized, and the visualized image is recorded. After the image is transferred to the medium, the image on the recording medium is passed through a fixing device to fix the image on the recording medium, and the developer remaining on the electrostatic latent image carrier after the transfer is removed by a cleaning device. The temperature of the developer conveying path and the developer accommodating portion in the apparatus is controlled to be equal to or lower than the glass transition temperature of the toner resin constituting the developer, and the developer carrier surface roughness Rz1
Is 1 to 50 μm, and the surface roughness Rz1 of the developer carrying member and S
m1 and the developer toner number average particle diameter dt have the following relationship.

Sm1 / Rz1 ≧ 2, Rz1> dt / 4 [2] A toner constituting the developer is manufactured by a polymerization method, the coefficient of variation of the shape factor of the toner is 16% or less, and the number in the number particle size distribution is The image forming method according to [1], wherein the coefficient of variation is 27% or less.

[3] A toner constituting the developer is produced by a polymerization method, and the toner is composed of toner particles having no corners.
The image forming method according to [1], wherein the number is 0% or more and the number variation coefficient in the number particle size distribution is 27% or less.

[4] A toner constituting the developer is produced by a polymerization method, and the toner has a shape factor of 1.2 to 1.
6. The image forming method according to [1], wherein the toner particles in the range of 6 are 65% by number or more and the variation coefficient of the shape coefficient is 16% or less.

[5] The method for forming an image according to any one of [1] to [4], wherein the toner comprises a toner and a carrier, and has a number average particle diameter of 3 to 8 μm. Two-component developer.

[6] A one-component developer which is used in the image forming method according to any one of [1] to [4] and has a toner number average particle diameter of 3 to 8 μm. .

[7] The electrostatic latent image formed on the electrostatic latent image carrier is developed by using a developer layer carried on the developer carrier to be visualized, and the visualized image is recorded. In an image forming method for transferring an image on a recording medium to a fixing device for fixing the image on the recording medium, and removing a developer remaining on the electrostatic latent image carrier after the transfer by a cleaning device, the image forming apparatus The surface roughness Rz2 of the developer conveying path and the inner wall of the developer accommodating portion in which the developer in the container is in direct contact is set to be equal to or less than の of the toner number average particle diameter, and the developer carrier surface roughness Rz1 Wherein the developer carrying member surface roughness Rz1 and Sm1 and the developer toner number average particle diameter dt have the following relationships.

Sm1 / Rz1 ≧ 2, Rz1> dt / 4 [8] A toner constituting the developer is manufactured by a polymerization method, the coefficient of variation of the shape factor of the toner is 16% or less, and the number in the number particle size distribution is The image forming method according to [7], wherein the coefficient of variation is 27% or less.

[0019]

[9] A toner constituting the developer is manufactured by a polymerization method, and the toner is formed by using toner particles having no corners.
The image forming method according to [7], wherein the number is 0% or more and the number variation coefficient in the number particle size distribution is 27% or less.

[10] A toner constituting the developer is produced by a polymerization method, and the toner has a shape factor of 1.2 to 1.2.
The image forming method according to [7], wherein the number of toner particles in the range of 1.6 is 65% by number or more and the variation coefficient of the shape coefficient is 16% or less.

[11] The image forming method according to any one of [7] to [10], wherein the toner comprises at least a toner and a carrier, and has a number average particle diameter of 3 to 8 μm. Two-component developer.

[12] A one-component developer which is used in the image forming method according to any one of [7] to [10] and has a toner number average particle diameter of 3 to 8 μm. .

[13] It has an electrophotographic photosensitive member, a charger, an image exposure device, and a developing device, and has a toner number average particle diameter of 3 to 8 μm.
An image forming apparatus, wherein an image is formed by using the image forming method according to [1] or [7] using the developer described in [1].

The surface roughness Rz in the present invention is defined by JIS
It is the ten-point average roughness in the standard, and the average elevation of the top of the sample cross-sectional curve of the reference length L and the bottom of the valley of the depth from the first to fifth This is the average altitude interval. Sm is Sm in the ISO standard, and the roughness curve of the evaluation length N times the sampling length is expressed by N
It is the arithmetic mean value of the average interval Sm 'of the interval of the unevenness (the width of a pair of adjacent peaks and valleys) for each section.

As described above, it is effective to use a small-diameter polymerized toner produced by a polymerization method in order to improve image quality. As will be described in detail later, for example, the coefficient of variation of the shape coefficient is set to 16% or less, and the coefficient of number variation of the number particle size distribution is set to 27% or less. That is, the weight is uniform, the corners are round, and the particle size distribution is sharp. The legal toner is less likely to be destroyed than the pulverized toner, generates less fine powder, and can prevent the occurrence of image fogging and the occurrence of contamination in the apparatus due to toner scattering.

However, the developer granules due to toner fusing and sticking, which are likely to be generated by using a small-diameter toner, cause transfer failure, increase in torque of a transport system, and a packing problem. In order to prevent this, it is important that the temperature of the developer conveying path and the developer accommodating portion in the image forming apparatus be equal to or lower than the toner glass transition temperature, that is, the temperature is not increased until the toner softens. is there.

Alternatively, the surface roughness Rz2 of the developer conveying path and the developer accommodating portion where the developer in the image forming apparatus comes into direct contact is set to be not more than の of the toner particle diameter.
In other words, it is also important to prevent the toner from being fused or fixed by allowing the toner to move smoothly without being caught by the wall and staying.

However, these techniques are still insufficient for maintaining good characteristics over a long period of time, and the present inventors have conducted further studies and reached the present invention.

That is, as a measure for preventing the toner from being fused to the developer carrier, the surface roughness Rz1
And Sm1 and the developer toner average particle diameter dt,
It was found that it was necessary to satisfy the following relational expression.

That is, Sm1 / Rz1 ≧ 2, Rz1> dt
/ 4 and Rz1 = 1 to 50 μm, preferably 1 to
Set to 30 μm. As a result, it was possible to prevent the toner from being fused to the developer carrying member (developing sleeve) and secure the transport performance of transporting the developer to the developing area.

1. Influence of Temperature in Image Forming Apparatus The study conditions were as follows.

Developer and Image Forming Apparatus Toner is a spherical polymerized toner (styrene-acrylic, having a number average particle diameter of 3, 6.5, 8, 9, 10 μm) and an irregular pulverization method. A toner (styrene-acryl type having a number average particle diameter of 3, 6.5, 8, 9, 10 μm) was used.

As the carrier, a ferrite carrier (silicone resin coat) having a volume particle size of 60 μm was used. The toner concentration is 4.5% by mass.

The image forming apparatus used in the experiment was a Konica 7065 modified machine (monochrome digital copier / printer) manufactured by Konica, 600 dpi, laser beam diameter main scanning 55 μm / sub scanning 80 μm, a toner recycling mechanism from the cleaning device to the developing device. It is equipped with.

The experimental environment was 20 ° C. and 50% RH. FIG. 1 shows a configuration diagram of an image forming apparatus as an experimental device for confirming effects of the present invention.

The temperature of the developer conveying path and the temperature of the developer accommodating portion are not shown, but a suction fan for introducing outside air into the image forming apparatus and an exhaust fan for discharging warm air inside the apparatus are installed. ON / OFF and air flow adjustment, and furthermore, the control was set by installing the apparatus body in the environment control room.

The surface roughness of the developer transport path and the wall of the developer accommodating portion can be changed by sandblasting conditions. Although not shown, the developing device and the cleaning device are connected by a toner recycling pipe. Note that, in practice, the experiment was performed first from the smaller toner particle size.

In the figure, reference numeral 1 denotes a photosensitive member (electrostatic latent image carrier);
Is a charging device, 3 is an exposure optical device, 4 is a developing device (developing device), 5 is a transfer device, 6 is a separating device, 7 is a fixing device (fixing device), 8 is a cleaning device, 9 is a paper feed cassette,
1 is a developer carrier, 71 is a heating roller, 72 is a pressure roller, 81 is a cleaning blade, 82 is a toner guide roller, and P is a paper passage path (recording medium passage path).

Further, in this experiment, the surface roughness Rz2 of the developer transporting path and the inner wall of the developer accommodating portion where the developer in the image forming apparatus is in direct contact is 1/1/1 of the toner number average particle diameter under any condition. 2 or less.

Evaluation items: At the start and after 10,000 copies of an A4 printing rate 5% original. A) Image quality characteristics: Isolated dot (1 dot) reproducibility, non-printing area fog, sharpness of solid black edge portion (mainly Scan direction 10
0 mm x 50 mm patch in the sub-scanning direction) b) Granule generation status: presence or absence of transfer nuisance (determined based on full solid black and full halftone image output of A3), c) Fusion bonding status: increase in torque in developer transport path Judgment was made based on the presence and absence of packing.

First, the temperature during copying in the image forming apparatus was measured. FIG. 2 shows a change in the temperature in the cleaning device depending on the copy time. In the experiment, the temperature of the developer conveyance path and the temperature of the other portions in the developer accommodating portion were equal to or lower than the above.

The horizontal axis represents the copy time, the vertical axis represents the temperature in the cleaning device, the number average toner particle diameter is 6.5 μm, and the glass transition temperature Tg of the toner used in the experiment is 55 ° C. The temperature was 57 ° C. (detection was confirmed by image output and an increase in drive system torque).

When the temperature inside the machine is increased (each fan OF
In F), the temperature reached not lower than the glass transition temperature of the toner after 60 minutes, and the toner was fused and fixed. On the other hand, when the internal temperature is lowered (each fan is ON), the saturation is stabilized at a temperature lower than the fusion-fixing temperature of 42 ° C. after 90 minutes without any trouble, and the temperature of the developer transport path and the developer storage portion is lowered. The effect was confirmed.

Thereafter, an experiment of 10,000 continuous copies was carried out in the same manner by changing the type of toner. The results are shown in Table 1 below, and the experimental results are shown in Table 2 below the glass transition temperature of the toner.

In the table, ◎ means extremely good, means that there is no practical problem, Δ means that the problem is somewhat bad in practical use, and × means extremely bad.

[0046]

[Table 1]

[0047]

[Table 2]

From Table 1, it can be seen that below the glass transition temperature of the toner, if the toner particle size is in the range of 3 to 8 μm, the image quality is good even after 10,000 copies, and there is no increase in driving torque or packing. This indicates that neither generation of granules nor fusion bonding was caused. It can also be seen that the polymerized toner and the pulverized toner have better characteristics.

It can be seen that the toner particles having a particle diameter of 9, 10 μm have a problem in the reproducibility of isolated dots from the beginning. Further, a toner having a toner particle diameter of 2 μm or less is not practically preferable because it is difficult to charge the toner, and it is conceivable that toner scattering is increased and a respiratory system of humans may be adversely affected.

On the other hand, as is apparent from Table 2, under the condition that the temperature exceeds the glass transition temperature of the toner, 1
The characteristics after 10,000 copies are extremely poor, indicating that continuous copying at a temperature equal to or higher than the glass transition temperature of the toner is extremely problematic. In comparison between the polymerized toner and the pulverized toner, the polymerized toner was more deteriorated in characteristics.

2. Influence of the surface roughness Rz2 of the developer conveying path and the wall of the developer accommodating part The experiment environment was maintained at 20 ° C. and 50% RH, and the temperature in the image forming apparatus was adjusted to 42 ° C. The effect was evaluated in accordance with "Influence of temperature in image forming apparatus".

When Rz2 is less than half of the toner number average particle diameter, the results shown in Table 3 below were obtained.

[0053]

[Table 3]

In this case, if the particle size of the toner is 3 to 8 μm, the image quality is good even after 10,000 copies, no generation of granules or fusion and fixation of the toner occurs, and the overall characteristics are as follows. The polymerization toner was more favorable.

Table 4 shows the results under the condition that Rz2 exceeds ト ナ ー of the toner number average particle diameter in the same manner.

[0056]

[Table 4]

In this case, it can be seen that the characteristics such as the reproducibility of isolated dots and the occurrence of fogging after 10,000 copies are extremely deteriorated. In addition, torque increase and packing were observed, indicating that granules were generated.

3. Developer carrier surface roughness Rz1 and Sm
The relationship between 1 and the number average particle diameter dt of the toner is as follows. The test conditions are as follows: the polymerization toner is used, the temperature in the image forming apparatus is 42 ° C. The diameter was set to 1/2 or less. Otherwise, the results of 50,000 actual copies taken according to the test conditions are shown in Table 5 below.

[0059]

[Table 5]

The relationship between the developer carrier surface roughness Rz1 and Sm1 and the toner number average particle diameter dt is Sm1 / Rz1 ≧
2. Those satisfying the relationship of Rz> dt / 4 have good image quality even after 50,000 copies, and it can be seen that the toner can be prevented from being fused and fixed to the developer carrying member.

On the other hand, Sm1 / Rz1 <2, Rz ≦
It can be seen that in the range of dt / 4, toner fusing and fixing occur before 50,000 copies, and the image quality becomes poor.

The method of displaying the characteristics was in accordance with Table 1 above.

[0063]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing the toner used in the present invention is not particularly limited, and is not limited to the following. However, toners which can be preferably used are those produced by a so-called polymerization method. (Usually referred to as a polymerization toner).

Specifically, the monomer is emulsion-polymerized in a suspension produced by a suspension polymerization method or in a liquid to which an emulsion of necessary additives is added to produce fine polymer particles. , An organic solvent, a coagulant, etc., and can be produced by association. A method of preparing by mixing and associating with a dispersion liquid such as a release agent or a colorant necessary for the composition of the toner at the time of association, or dispersing a toner component such as a release agent or a colorant in a monomer. And then emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

The aqueous medium in the present invention means a medium containing at least 50% by mass of water.

That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic dispersion Various constituent materials are dissolved or dispersed in the polymerizable monomer by a machine or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an aqueous medium containing a dispersion stabilizer into oil droplets of a desired size as a toner using a homomixer, a homogenizer, or the like. Thereafter, the stirring mechanism is moved to a reaction device, which is a stirring blade described later, and heated to cause the polymerization reaction to proceed. After completion of the reaction, the toner of the present invention is prepared by removing the dispersion stabilizer, filtering, washing and drying.

As described above, a method for preparing the toner of the present invention by associating or fusing resin particles in an aqueous medium can also be preferably used. Although this method is not particularly limited, for example, JP-A-5-265252 and JP-A-6-329
947 and JP-A-9-15904. That is, a method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or a plurality of fine particles composed of a resin and a colorant, particularly, after dispersing these in water using an emulsifier, the critical aggregation concentration At the same time as adding the above flocculant and salting out, the formed polymer itself is heated and fused at a temperature equal to or higher than the glass transition temperature to gradually form a fused particle, thereby gradually growing the particle size. At this point, a large amount of water was added to stop the growth of the particle diameter, and the surface was smoothened by heating and stirring to control the shape. The toner of the invention can be formed. Here, an organic solvent infinitely soluble in water may be added together with the coagulant.

Regardless of which method is used, the one used as the polymerizable monomer constituting the resin is styrene, o-
Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,
4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-ter
t-butylstyrene, pn-hexylstyrene, p-
n-octylstyrene, pn-nonylstyrene, p-
Styrene such as n-decylstyrene, pn-dodecylstyrene or a styrene derivative, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylate Octyl, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and other methacrylate derivatives, methyl acrylate, ethyl acrylate, isopropyl acrylate, N-butyl acrylate, t-butyl acrylate,
Acrylate derivative such as isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc .; olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride Vinyl halides such as vinyl bromide, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl methyl ketone , Vinyl ethyl ketone, vinyl hexyl ketone, and other vinyl ketones, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, and other N-vinyl compounds, vinyl naphthalene, vinyl pyridine, and other vinyl compounds Acrylonitrile, methacrylonitrile, there are acrylic acid or methacrylic acid derivatives such as acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a polymerizable monomer constituting the resin in combination with one having an ionic dissociation group. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, and fumaric acid. Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl methacrylate, 3
-Chloro-2-acid phosphooxypropyl methacrylate and the like.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate,
Polyfunctional vinyls such as neopentyl glycol diacrylate can be used to form a crosslinked resin.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As the oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo or diazo polymerization initiators such as nitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide , Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-
Examples include peroxide-based polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in a side chain. .

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, and calcium sulfate. , Barium sulfate,
Bentonite, silica, alumina and the like can be mentioned. Further, a surfactant generally used as a surfactant such as polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as a dispersion stabilizer.

The resin excellent in the present invention preferably has a glass transition point of 20 to 90 ° C. and a softening point of 8 ° C.
The thing of 0-220 ° C is preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Furthermore, these resins have a number average molecular weight (Mn) of 10 as measured by gel permeation chromatography.
00 to 100000, weight average molecular weight (Mw) 200
Those having 0 to 1,000,000 are preferred. Further, as a molecular weight distribution, Mw / Mn is 1.5 to 100, particularly 1.8.
-70 are preferred.

The flocculant to be used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, a salt of an alkali metal such as sodium, potassium, and lithium, and as a divalent metal, for example, a salt of an alkaline earth metal such as calcium and magnesium, or a divalent metal such as manganese or copper Salt,
Examples include salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Can be.
These may be used in combination.

It is preferable to add these coagulants at a concentration higher than the critical coagulation concentration. The critical aggregation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which aggregation occurs when a coagulant is added. This critical aggregation concentration is
It varies greatly depending on the emulsified component and the dispersant itself. For example, Seizo Okamura et al.
7, 601 (1960), edited by The Society of Polymer Science, Japan, and the like, and a detailed critical aggregation concentration can be determined.
As another method, a desired salt is added to the target particle dispersion at a different concentration, the 、 (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can also ask.

The addition amount of the coagulant of the present invention may be not less than the critical coagulation concentration, but is preferably 1.2 to the critical coagulation concentration.
It is better to add it at least twice, more preferably at least 1.5 times.

The solvent which is infinitely soluble means a solvent which is infinitely soluble in water, and in the present invention, a solvent which does not dissolve the formed resin is selected.
Specifically, methanol, ethanol, propanol,
Examples thereof include alcohols such as isopropanol, t-butanol, methoxyethanol and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferred.

The amount of the solvent to be dissolved infinitely is 1 to 100% by volume based on the polymer-containing dispersion to which the flocculant is added.
Is preferred.

In order to homogenize the shape, it is preferable to prepare a colored particle, and after the filtration, a slurry in which water is present in an amount of 10% by mass or more based on the particle is fluidized and dried. Those having a polar group in the polymer are preferred. It is considered that the reason for this is that the existing water exerts an effect of slightly swelling the polymer in which the polar group is present, so that it is particularly easy to make the shape uniform.

The toner of the present invention contains at least a resin and a colorant, but may also contain a releasing agent or a charge control agent as a fixing property improving agent, if necessary. Further, an external additive composed of inorganic fine particles, organic fine particles, and the like may be added to the toner particles containing the resin and the colorant as main components.

As the colorant used in the toner of the present invention, carbon black, magnetic substance, dye, pigment and the like can be arbitrarily used. As the carbon black, channel black, furnace black, acetylene black, and the like can be used.
Thermal black, lamp black and the like are used. Ferromagnetic metals such as iron, nickel, and cobalt as magnetic materials,
Alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but show ferromagnetism by heat treatment, such as manganese-copper-
An alloy of a type called a Heusler alloy such as aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, 79, 81, 82, 93, 98, 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like, and a mixture thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122,
139, 144, 149, 166, 177,
178, 222, C.I. I. Pigment Orange 3
1, 43, C.I. I. Pigment Yellow 14, 1
7, 93, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60
And the like, and a mixture thereof can also be used. Although the number average primary particle size varies depending on the type,
The thickness is preferably about 10 to 200 nm.

As a method of adding a coloring agent, a method of adding polymer particles prepared by an emulsion polymerization method at the stage of aggregating by adding an aggregating agent to color the polymer, or a stage of polymerizing a monomer. And a method of adding a coloring agent to obtain colored particles. When the colorant is added at the stage of preparing the polymer, it is preferable to use the colorant after treating the surface with a coupling agent or the like so as not to inhibit the radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000) or low molecular weight polyethylene as a fixing property improving agent may be added.

The charge control agents are also various known ones.
What can be dispersed in water can also be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof.

The particles of the charge controlling agent and the fixability improving agent have a number average primary particle diameter of 10 to 500 in a dispersed state.
It is preferable to set it to about nm.

A suspension polymerization toner in which a toner component such as a colorant is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner. By controlling the flow of the medium in the reaction vessel, the shape of the toner particles can be controlled. That is, when a large number of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is made turbulent, and the polymerization proceeds to be present in the aqueous medium in a suspended state. When the oil droplets are gradually polymerized, the oil droplets become soft particles, and when the oil droplets collide, the coalescence of the particles is promoted, and particles with an irregular shape are obtained. . When spherical toner particles having a shape factor smaller than 1.2 are to be formed, spherical particles can be obtained by using a medium flow in the reaction vessel as a laminar flow to avoid collision of the particles. By this method, the distribution of the toner shape can be controlled within the range of the present invention.

Further, in the toner of the present invention, more effects can be exhibited by adding and using fine particles such as inorganic fine particles and organic fine particles as external additives.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania and alumina. Further, it is preferable that these inorganic fine particles have been subjected to a hydrophobic treatment with a silane coupling agent or a titanium coupling agent. preferable. The degree of the hydrophobic treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is to evaluate the wettability to methanol. In this method, inorganic fine particles to be measured are added to 50 ml of distilled water placed in a beaker having a capacity of 200 ml.
Weigh 2 g and add. Methanol is slowly dropped from a burette whose tip is immersed in the liquid until the whole of the inorganic fine particles becomes wet while being slowly stirred. When the amount of methanol required to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following equation.

Degree of hydrophobicity = (a / (a + 50)) × 100 The amount of the external additive added is 0.1 to 5.
0 mass%, preferably 0.5 to 4.0 mass%. Various external additives may be used in combination.

The shape factor of the toner of the present invention is represented by the following equation, and indicates the degree of roundness of toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter is defined as the parallel line when a projected image of a toner particle on a plane is sandwiched between two parallel lines. Means the width of the particle at which the distance between the particles becomes maximum. The projection area refers to the area of the projected image of the toner particles on the plane.

In the present invention, the shape factor can be determined by taking a photograph obtained by enlarging the toner particles by 2000 times with a scanning electron microscope, and referring to the “SCCANNING” based on the photograph.
The measurement was performed by analyzing a photographic image using "IMAGE ANALYZER" (manufactured by JEOL Ltd.). In this case, the shape factor of the present invention was measured by using the above formula using 100 toner particles.

The variation coefficient of the shape factor of the toner of the present invention is calculated from the following equation. Coefficient of variation = (S / K) × 100 (%) (where S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.) Is preferably 16% or less, more preferably 14% or less.

The number particle size distribution represents the relative frequency of toner particles with respect to the particle size.
It represents the median diameter in the number particle size distribution.

The number variation coefficient in the number particle size distribution of the toner is calculated from the following equation. Number variation coefficient = (S / Dn) × 100 (%) (where S represents the standard deviation in the number particle size distribution, and D
n indicates a number average particle size (μm). The number variation coefficient of the toner of the present invention is preferably 27% or less, more preferably 25% or less.

In the present invention, the toner particles having the shape factor in the range of 1.2 to 1.6 are preferably at least 65% by number, more preferably at least 70% by number.
That is all.

The method for controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of adding a toner particle in a solvent that does not dissolve a toner to give a swirling flow, etc. Thus, there is a method in which a toner having a shape factor of 1.2 to 1.6 is prepared, and is added to a normal toner so as to fall within the range of the present invention. Also, controlling the overall shape at the stage of preparing a so-called polymerization toner,
There is a method in which a toner whose shape factor is adjusted to 1.2 to 1.6 is similarly added to a normal toner to adjust.

Among the above-mentioned methods, polymerization toners are preferable because they are simple as a production method, and are superior in surface uniformity as compared with pulverization toners.

In order to uniformly control the shape factor of the toner and the variation coefficient of the shape factor without variation in lots, the toner particles are being formed in a process of polymerizing, fusing, and controlling the shape of resin particles (polymer particles). The proper process end time may be determined while monitoring the characteristics of the toner particles (colored particles).

The term "monitoring" means that a measuring device is incorporated in-line and the process conditions are controlled based on the measurement result. That is, for example, in the case of a polymerization toner formed by incorporating measurement of shape and the like inline and assembling or fusing resin particles in an aqueous medium, the shape and particle size are sequentially measured in a process such as fusing. Is measured, and the reaction is stopped when the desired shape is obtained.

Although the monitoring method is not particularly limited, a flow type particle image analyzer FPIA-
2000 (manufactured by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field to constantly monitor and measure the shape and the like, and stop the reaction when the desired shape and the like are obtained.

The number particle size distribution and the number variation coefficient of the toner of the present invention are measured by Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter). In the present invention, a Coulter Multisizer was used by connecting an interface (manufactured by Nikkaki Co., Ltd.) for outputting a particle size distribution and a personal computer. The aperture used in the Coulter Multisizer is 100 μm and the aperture is 2 μm.
The number of the toners was measured to calculate the particle size distribution and the average particle size.

The toner particles having no corners according to the present invention are toner particles having substantially no projections on which electric charges are concentrated or projections which are easily worn by stress. The particles are called cornerless toner particles.
That is, as shown in FIG.
When a circle having a radius R of L / 10 is rolled in while being in contact with the periphery of the toner particle at one point, a corner is formed when the circle does not substantially extend outside the toner. No toner particles. The case where the protrusion does not substantially protrude means that the protrusion where the protruding circle exists is one or less. Further, the major axis of the toner particle refers to the width of the particle at which the interval between the parallel lines becomes maximum when the projected image of the toner particle on the plane is sandwiched between two parallel lines.

The measurement of the toner having no corner was performed as follows. First, a photograph in which toner particles are enlarged by a scanning electron microscope is taken, and further enlarged to obtain a photographic image of 15,000 times. Next, the presence or absence of the corners is measured for this photographic image. This measurement was performed for 100 toner particles.

In the toner of the present invention, the proportion of toner particles having no corners is preferably at least 50% by number, more preferably at least 70% by number. When the ratio of toner particles having no corners is 50% by number or more, generation of fine particles due to stress with a developer conveying member or the like is eliminated,
It is possible to prevent the presence of toner that is excessively adherent to the surface of the developer transport member, to suppress contamination of the developer transport member, and to sharpen the charge amount. In addition, the amount of toner particles that are easily worn or broken and the number of toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stabilized, and good image quality can be formed over a long period of time.

The method for obtaining a toner having no corners is not particularly limited. For example, as described above, as a method of controlling the shape coefficient, a method of spraying toner particles into a hot air flow, a method of repeatedly applying mechanical energy by an impact force in a gas phase, or a method of dissolving a toner It can be obtained by adding to a solvent that does not contain and giving a swirling flow.

In a polymerization toner formed by associating or fusing resin particles, the surface of the fused particles has many irregularities at the stage of stopping the fusion, and the surface is not smooth. By adjusting the conditions such as the temperature, the number of rotations of the stirring blade, and the stirring time, toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, when the rotation speed is higher than the glass transition temperature of the resin particles and the number of rotations is high, the surface becomes smooth and a toner having no corners can be formed.

The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. When toner particles are formed by a polymerization method, the particle diameter can be controlled by the concentration of the coagulant, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.

Next, regarding the numerical values according to the present invention, the numerical values of conventionally known toners will be described for reference. This value differs depending on the manufacturing method.

In the case of the pulverized toner, the shape factor is from 1.2 to
The ratio of the 1.6 toner particles is about 60% by number. The variation coefficient of the shape factor is about 20%. Further, in the pulverization method, in order to reduce the particle size while repeating crushing, the toner particles have many corners, and the ratio of toner particles having no corners is 30% by number or less. Therefore,
In order to obtain a rounded toner having no corners and a uniform shape, it is necessary to perform a process of forming a spherical shape by heat or the like as described above as a method of controlling the shape coefficient. In addition, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after the pulverization is performed once, and the classification operation needs to be further repeated to reduce the number variation coefficient to 27% or less. There is.

In the case of the toner obtained by the suspension polymerization method, the toner is conventionally polymerized in a laminar flow, so that substantially spherical toner particles are obtained. For example, in the toner described in JP-A-56-130762, The proportion of toner particles having a coefficient of 1.2 to 1.6 is about 20% by number, the variation coefficient of the shape coefficient is also about 18%, and the proportion of toner particles having no corners is also about 85% by number. Further, as described above in the method for controlling the number variation coefficient in the number particle size distribution, mechanical shearing is repeated for a large oil droplet of a polymerizable monomer to reduce the oil droplet to a size of a toner particle. Therefore, the distribution of oil droplet diameters is widened, and the particle size distribution of the obtained toner is wide, and the number variation coefficient is as large as about 32%. Therefore, a classification operation is required to reduce the number variation coefficient. .

Polymerized toners formed by associating or fusing resin particles are described in, for example,
In the toner described in Japanese Patent No. 186253, the proportion of toner particles having a shape factor of 1.2 to 1.6 is 60% by number.
The variation coefficient of the shape coefficient is about 18%, and the ratio of toner particles without corners is about 44% by number. The ratio of toner particles without corners is about 55% by number. Further, the particle size distribution of the toner is wide, and the coefficient of number variation is 30%. To reduce the coefficient of number variation, a classification operation is usually required.

Further, the developing method that can be used in the present invention is not particularly limited, and either a one-component developing method or a two-component developing method can be used. You can do it. Among them, a non-magnetic one-component developing method using a one-component developer or a method of mixing with a magnetic carrier to perform a magnetic two-component development as a two-component developer is preferable. As a carrier used for magnetic two-component development, a mixture of spherical iron powder particles, ferrite particles, and magnetite particles having a diameter of 30 to 100 μm is used.

[0116]

According to the present invention, a developer carrying member and a developer which come into direct contact with the developer, which are a major problem in the development of an image forming method and an image forming apparatus capable of obtaining a high quality and stable copy image for a long period of time. It is possible to provide a toner that does not cause image fusion, black streaks, and fogging based on toner fusion to the transport path and the inner wall of the developer accommodating portion and granulation there, and an image forming method and an image forming apparatus using the toner. I can do it.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to the present invention.

FIG. 2 shows a temperature change during copying in the cleaning device.

FIG. 3 is a diagram illustrating toner particles having no corners.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor (electrostatic latent image carrier) 2 charging device 3 exposure optical device 4 developing device (developing device) 5 transfer device 6 separation device 7 fixing device (fixing device) 8 cleaning device 9 paper feed cassette 41 developer carrier 71 Heating Roller 72 Pressure Roller 81 Cleaning Blade 82 Toner Guide Roller P Paper Passing Path (Recording Medium Passing Path)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toru Yamaguchi 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AB06 EA05 EA10 FA01 FA05 2H077 AD06 BA08 DA18 DB25 EA01 EA11 FA01 GA02

Claims (13)

[Claims] An electrostatic latent image formed on an electrostatic latent image carrier is developed using a developer layer carried on the developer carrier to develop an image, and the visualized image is recorded on a recording medium. In the image forming method, an image on the recording medium is passed through a fixing device to fix the image on the recording medium, and a developer remaining on the electrostatic latent image carrier after the transfer is removed by a cleaning device. The temperature of the developer conveying path and the developer accommodating portion is set to be equal to or lower than the glass transition temperature of the toner resin constituting the developer, and the surface roughness Rz1 of the developer carrier is set to 1 to 5
An image forming method, wherein the developer carrying member surface roughness Rz1 and Sm1 and the developer toner number average particle diameter dt have the following relationship. Sm1 / Rz1 ≧ 2, Rz1> dt / 4 2. The method according to claim 1, wherein the toner constituting the developer is produced by a polymerization method, the coefficient of variation of the shape factor of the toner is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less. The image forming method according to claim 1, wherein 3. A toner constituting a developer is produced by a polymerization method, wherein the toner has 50% by number or more of toner particles having no corners, and has a number variation coefficient of 2 in a number particle size distribution.
2. The image forming method according to claim 1, wherein the content is 7% or less. 4. A toner constituting a developer is manufactured by a polymerization method, wherein the toner has a shape factor in a range of 1.2 to 1.6, the number of toner particles is 65% by number or more, and the shape factor varies. 2. The image forming method according to claim 1, wherein the coefficient is 16% or less. 5. An image forming method according to claim 1, comprising at least a toner and a carrier,
A two-component developer, wherein the toner has a number average particle size of 3 to 8 μm. 6. A developer used in the image forming method according to claim 1, wherein the toner has a toner number average particle diameter of 3%.
A one-component developer having a thickness of from 8 to 8 μm. 7. An electrostatic latent image formed on an electrostatic latent image carrier is developed using a developer layer carried on the developer carrier to form a visualized image, and the visualized image is recorded on a recording medium. After the image is transferred to the image forming apparatus, the image on the recording medium is passed through a fixing device to fix the image on the recording medium, and the developer remaining on the electrostatic latent image carrier after the transfer is removed by a cleaning device. The surface roughness Rz2 of the developer transfer path and the inner wall of the developer accommodating portion where the developer directly contacts is set to be equal to or smaller than 1/2 of the toner number average particle diameter, and the developer carrier surface roughness Rz1 is reduced. An image forming method, wherein the surface roughness Rz1 and Sm1 of the developer carrier and the number average particle diameter dt of the developer toner have the following relationships. Sm1 / Rz1 ≧ 2, Rz1> dt / 4 8. A toner comprising a developer produced by a polymerization method, wherein the coefficient of variation of the shape factor of the toner is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less. The image forming method according to claim 7, wherein 9. A toner constituting a developer is produced by a polymerization method, wherein the toner has at least 50% by number of cornerless toner particles, and has a number variation coefficient of 2 in the number particle size distribution.
The image forming method according to claim 7, wherein the content is 7% or less. 10. A toner constituting a developer is produced by a polymerization method, wherein the toner has a shape factor in the range of 1.2 to 1.6, the toner particles are 65% by number or more, and the shape factor is varied. The image forming method according to claim 7, wherein the coefficient is 16% or less. 11. A two-component developing method for use in the image forming method according to claim 7, comprising at least a toner and a carrier, wherein the number average particle diameter of the toner is 3 to 8 μm. Agent. 12. The one-component developer according to claim 7, wherein the toner has an average particle diameter of 3 to 8 μm. 13. An electrophotographic photosensitive member, a charger, an image exposure device,
An image forming apparatus comprising: a developing device; and a developer having a toner number average particle diameter of 3 to 8 μm, and forming an image using the image forming method according to claim 1.