JPS593445A - Electrophotographic developer - Google Patents

Abstract

PURPOSE:To obtain efficient triboelectricity, by sticking molten fine powder of a fluorine-containing polyacrylate to the surface of particles prepd. by dispersing a colorant into a binder resin. CONSTITUTION:Fine powder of a fluorine-contg. polyacrylate is represented by the formula in which R1 is methyl, ethyl, propyl, or halogen, R2 is CnH2n+1 with >=2H substd. for >=2 F or F and Cl, and n is an integer of 1-18. It is melted and stuck to the surface of particles prepd. by dispersing a colorant into a binder resin. it is desirable that said polymer has a particle diameter <=1/10 of that of said particles and the softening point or m.p. of said polymer is 80-160 deg.C.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] Is the present invention an electrostatic latent image of electrophotography or electrostatic recording? The present invention relates to a developer used for visualization, and more specifically to a one-component developer that does not use a carrier.

[Prior art and its problems]

Conventionally, as a developing method for electrophotography, for example, I'l
- No. 2.874.063, No. 2.618.552.

A number of developing methods are known, such as the magnetic brush method, the cascade method, the powder cloud method, and the fur brush method described in Japanese Patent No. 2.221.776 and No. 2.902.974.

Among these developing methods, two-component magnetic brush developing methods and cascade developing methods using toner and carrier as living organisms are generally put into practical use.

All of these developing devices are relatively stable and can easily produce images of excellent image quality.

However, despite these excellent features, is it a two-component developer? Common disadvantages of using it? have.

That is, the gold toner acquires a triboelectric charge due to the mutual friction between the toner and the carrier, but after long-term use, the surface of the carrier becomes contaminated with the toner composition, making it impossible to obtain a sufficient charge. The mixing ratio of carrier and carrier must be adjusted within a specified range, but for long-term use vC
L may fluctuate and deviate from the specified range.Furthermore, iron powder or glass beads with oxidized surfaces are used as carrier materials, and this may mechanically damage the surface of the photoreceptor. Issues such as:

In order to avoid such drawbacks, a one-component developer consisting only of toner is used as a developer. Various developing methods have been proposed.

In particular, many development methods using what is generally called a magnetic toner, which has magnetism as a toner, have been proposed, and U.S. Pat.
A developing method based on No. et al. has been put into practical use.

In the development method using these magnetic toners, since magnetic toners with relatively low resistivity are used, the developed image on the electrostatic latent image? Electrostatic transfer to a support member such as plain paper is difficult, especially in a humid atmosphere F, and sufficient transfer cannot be obtained.

Furthermore, magnetic powder that is magnetically sensitive? There are drawbacks such as the inability to obtain color toner because it is contained in a large amount.

That drawback? Does the toner not contain any magnetic powder to eliminate high resistivity? Recently, developing methods using toners having the above-mentioned properties have been attracting particular attention.

For example, U.S. Patent No. 2.895.847, U.S. Pat.
52.012, etc., and Special Publication No. 41-9475. Tokuko Showa 4
Touchdown method described in 5-2877, % Kosho 54-3624, etc.! Various developing methods based on the impression method and the jumping method have been proposed.

However, in order to carry out this complicated development method, toners used in conventional two-component systems were used;
- There are various problems with the component system.

For example, as disclosed in Japanese Patent Application Laid-Open No. 53-3237, the toner's hygroscopicity causes a decrease in charging efficiency, a decrease in developing ability, and aggregation of the toner. In addition to this, - component-based magnetic powder? Free non-magnetic toner 4'! There are some problems.

First, in the jumping development method disclosed in Japanese Patent Application Laid-Open No. 55-18657, etc., the toner must be efficiently charged by friction with a developer carrier, so-called sleeve.
Conventional toners are not always sufficient. Further, in color toners, polarity control agents having coloring properties such as dyes cannot be used.

Second, is the development method disclosed in JP-A-52-143831 using toner? It must be applied extremely thinly and uniformly onto the developer carrier.

To meet this difficult requirement, it is desirable that the toner has good fluidity and does not agglomerate, but there is no casing that is sufficient.

As a means to improve fluidity and eliminate aggregation, Japanese Patent Publication No. 54-16219. Some improvements have been made in adding or containing hydrophobic silica to sea urchins, as described in Japanese Patent Publication No. 54-20344, etc., but this is not sufficient.

In other words, when hydrophobic silica is externally added to the toner described in Japanese Patent Publication No. 54-16219, the hydrophobic silica separates from the toner and accumulates on the developer carrier during long-term use, causing negative effects on development. give. In addition, as described in Japanese Patent Publication No. 54-20344, when hydrophobic silica is added, a large amount of hydrophobic silica is contained in order to show the effect, which causes problems in color reproduction, especially in the case of color toner. .

The third problem is the adhesion of the toner composition to the developer carrier during long-term use, ie, so-called filminking.

For example, JP-A-55-113071. Jitsukai 55-89
This phenomenon is especially noticeable in the toner coating method and toner charging method as disclosed in No. 13, and has become a major problem. Note that when filming occurs, phenomena such as ghost images occur.

As a means to completely solve this problem,
There is a method of adding polytetrafluoroethylene to the sea urchin described in Section 4, but as mentioned above, as with the addition of hydrophobic silica, the polytetrafluoroethylene separates over a long period of use, and furthermore, the developer It was not a perfect solution as it adhered to the supporting material.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks of conventional electrophotographic developers and single-component developers, the first of which is:
The purpose of the present invention is to provide a developer that can achieve efficient triboelectric charging.

The second is good fluidity and cohesion? The purpose is to provide a developer that does not cause any damage.

The third objective is to provide a developer that does not cause filming on developer carriers, photoreceptors, etc. The fourth objective is to provide a developer that is not environmentally dependent.

The fifth objective is to provide a developer that is compatible with a -component nonmagnetic development method.

[Summary of the invention]

The electrophotographic developer of the present invention consists of particles in which a colorant is dispersed in a binder resin.
■～ is hydrogen, methyl, ethyl, propyl or halogen,
lζ is Cn14. . +1 hydrogen atom is replaced with 2 or more fluorine atoms or chlorine and fluorine atoms, and n is 1 to
It is an integer of 18.

This is an electrophotographic developer in which a fine powder of a fluorine-containing acrylic ester polymer shown in the formula is completely fused.

Furthermore, the particle size of the fine powder of the fluorine-containing acrylic acid ester polymer is less than or equal to the particle size of the particles in which the colorant is dispersed in the binder resin, and the softening of the fluorine-containing acrylic acid ester polymer Point or melting point is 80°C ~ 16
It is a developer for electrophotography with a temperature range of 0 DEG C., and is particularly suitable for a non-magnetic developing method using a component.

The entire manufacturing process of the present invention will be explained in detail.

Various thermoplastic resins are used as the binder resin in the electrophotographic developer (hereinafter referred to as toner) of the present invention.

For example, various styrene resins and various acrylic resins.

Various epoxy resins, vinyl chloride, vinyl acetate, polyvinyl butyral, vinylidene chloride, phenolic resin, 71
/ Inic acid resin, Coumaron resin, polycarbonate resin・
Examples include nylon resin, polyester resin (b) asphalt, dumble, etc. or copolymers thereof, polyether resin, polyurethane resin (t) and cellulose resin.

1fc, the melting point or softening point of these binder resins is 60
It is good to have a temperature in the range of °C to 200 °C, preferably 80 °C.
A range of 160°C to 160°C is preferable.

As the coloring agent used in the present invention, what is generally called a dye or pigment or various types of carbon black are used, and in some cases, a mixture of the above-mentioned coloring agents or magnetic powder is used.

For example, phthalocyanine blue, nigrosine, carmine red,
Various basic dyes 9 anthraquinone dyes.

Examples include azo dyes.

Further, as a color developer, a benzine-based yellow organic pigment is preferable as a yellow developer, specifically Color Intex Number 21090.
．． 21095.21100 etc. are preferable. Preferred magenta developers include quinawadrin-based magenta growth pigments and tardamine-based magenta organic pigments. Further, as the cyan developer, a phthalocyanine-based blue organic pigment is preferable.

Thus, the total amount of colorant for the binder resin described above is about 1-5%.
Add 0% by weight for general mixing and pulverization.

After going through the granulation process of classification, electron particles having an average particle size of about 10 μm, for example, are created by dispersing a coloring agent in a binder resin.

For example, double-arm kneaders and co-kneaders are used for cross-conducting.

Three rolls, etc. are used for pulverization, such as a Noonmar mill, a jet mill, a ball mill, and for one classification, a wind classifier, a sieve, etc. are used.

Next, the entire process of fusing fine powder of a fluorine-containing acrylic acid ester polymer to the surface of the prepared particles will be explained.

First, a fine powder of a fluorine-containing acrylic ester polymer is prepared.

To exemplify several methods for production, the first is the most common method of pulverization, in which the above-mentioned special mill, jet mill, ball mill, etc. are used for pulverization.

The second method is to dissolve it in a suitable solution, such as toluene or ethyl cellosolve, and then spray dry it. However, this method requires the use of a solvent. There are many problems associated with solvents such as recovery.
Undesirable.

The third method is mechanochemical, which is known as one of the surface treatment methods for powder. (Reference Koishi et al. Shikizai 51 (9)
, 511-519 (1978)) To use this method, first, a polymer of a fluorine-containing acrylic ester is prepared using appropriate means such as full sphere transfer granulation. The particles of the coloring agent dispersed in the binder resin mentioned above are placed in a ball mill pot and stirred for an appropriate period of time to disperse the colorant into the entire binder resin. The treatment step is completed by adhering to the surface of the dispersed particles.

This method is an effective method that can omit the entire mixing step, which will be described later, and can easily produce fine particles, and is preferred as the method for producing the electrophotographic developer of the present invention.

Next, a step of adhering the fine powder of the fluorine-containing acrylic ester polymer obtained by the first and second methods above to the surface of particles in which a colorant is dispersed in a binder resin. It is.

For this process, for example, a ball mill, a Kooningplender! Various mixers such as a Henschel mixer are used.

This process can be done by dispersing the coloring agent in the binder resin and mixing it with the fixed particles and the fine particles of the fluorine-containing acrylic ester polymer, which will give the best adhesion. In order to achieve this, it is preferable that the particle size of the fine powder of the fluorine-containing acrylic ester polymer is less than or equal to the particle size of the particles in which the colorant is dispersed in the binder resin.

O For example, since the particles created above are about 10 μm, 1
A fine powder of a fluorine-containing acrylic ester polymer having a size of 1 μm or less is used.

The reason for this is that it becomes easier to adhere electrostatically,
It is conceivable that the fine powder is mechanically embedded into the surface of the particles.Furthermore, setting the number to 1 or more may increase the price of the developer. It doesn't work.

By the way, is there a coloring agent in the binder resin? This is a step of fusing the fine powder of the fluorine-containing acrylic ester polymer adhering to the surface of the dispersed particles.

This process includes, for example, the inventors of the present invention [U.S. Pat.
It can be made by using the method for spheroidizing thermoplastic particles and the spheroidizing apparatus thereof, which are described in No. 5 and others.

For example, if the softening point of the fluorine-containing acrylic ester polymer is 600 to 200°C, the temperature of the hot air jetted from the heat exchanger is 2200'C to 600°C.
As 0.1~5m8Δnin, 01
~2 m'/min air volume r 0.01~2 Kf/
While blowing in a dispersion air stream with a particle dispersion concentration of 1 to 1000 fAnB at a pressure of cm', fine particles of a fluorine-containing acrylic ester polymer were applied to the surface of particles in which a colorant was dispersed in a binder resin. Can fuse powder.

Using such a method and apparatus, it is possible to fuse a fluorine-containing acrylic ester polymer having a softening point or melting point of up to 200°C.

If the fluorine-containing acrylic ester polymer has a softening or melting point of 60°C or higher, it is not recommended because it will cause agglomeration during storage in an electrophotographic device. It's not right.

However, it is possible to fuse even if the softening point or melting point of the fluorine-containing acrylic ester polymer is 200°C or higher. For this purpose, any binder resin containing a colorant having a melting point or softening point in the range of 60 DEG to 200 DEG C. may be used. Then, the binder resin is melted and a fused and spherical developer is obtained. The most desirable thing is
It is preferable that the softening point or melting point of the binder resin containing the fluorine-containing acrylic ester polymer and the coloring agent is in the range of 60° to 200° C., and that the values are approximately the same.

If this method is selected, a developer which is spherical and has a smooth surface can be obtained.

However, the fluorine-containing acrylic used in the present invention,
hydrogen, methyl, ethyl, propyl or halogen, crane is C11], n + □ hydrogen atoms are replaced with 2 or more, fluorine atoms or chlorine and fluorine atoms, where n is 1 to 1
It is an integer of 8.

This is shown in .

u/

Polypentadecafluorooctyl methacrylate Polypentadecafluorooctyl acrylate! Polypeptafluoroisoglobyl methacrylate t polyhebutafluoroisopropyl acrylate, polymonochlorohexafluoropropyl methacrylate, polytrifluoroether α-chloroacrylate 9 polyhexafluorobutyl methacrylate, polydimethyltetrafluoropropyl methacrylate, and the like.

〔Effect of the invention〕

According to the electrophotographic developer of the present invention, ■Efficient frictional charging can be obtained.

■Good fluidity and no agglomeration.

■No filming occurs on the developer carrier, photoreceptor, etc.

■No environment dependence.

- Compatible with non-magnetic current method for acid components.

(2) It is easy to form a thin layer of the developer on the developer carrier.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to Examples.

Example 1 Styrene-n-butyl methacrylate copolymer (Sanyo Kasoko Kogyo Hymer SBM-73) 90 X Okibe and carbon black (Mitsubishi Kasei MA-100) 10
After blending for about 10 minutes using a heavy TM and YT mixer, the mixture was kneaded for about 3 hours using a double-arm kneader.

After cooling, it was roughly crushed with a hammer mill and classified using a jet mill to obtain colored particles with an average particle size of 12 μm.The colored particles are now used as a two-component developer! It is fully usable.

Next, a polymer of fluorine-containing acrylic ester (Toshi,
Polytrifluoroethyl α-chloro 7-trifluoride) All of the mixture was spray-dried to create a fine powder of 1 μm or less.

1 g of this was added to the colored particles and applied to the warning blender to completely adhere the fine powder of the fluorine-containing acrylic ester polymer to the surface of the colored particles.

Next, a thermoplastic particle spheroidizing device was heated with hot air at a temperature of 40°C.
0°C, hot air, t 1 m'/min p particle emitted air i
pressure of 0.1 K1i/cm'', wind [10,3 m'/m
in + IIC setting L s particle dispersion concentration 110P/m
The developer of the present invention was obtained by spheroidizing and simultaneously fusing a fine powder of a fluorine-containing acrylic ester polymer to the surface of the colored particles.

Developer gold plow-off zone foot measuring device of the present invention [Electrophotography 16. (1977) 52. Journal of the Society of Electrostatics 4 (1980)
134 etc.] using Obi 1! As a result of investigating the characteristics, it is approximately 32μc
I got pregnant because of the fast start-up of /p-1.

For comparison, when the colored particles mentioned above were examined in the same manner, the rise was also slow at about 12 μc/fr. This is shown in Figure 1.

Next, when the fluidity was measured by adding the angle of repose, it was found that the developer a of the present invention had an angle of 33°, whereas the colored particles b had a p1 fluidity of 40°, which was significantly improved.

In addition, storage test [Developer 2074 was put in a wide-mouth 100al' polyethylene bottle, pinked several dozen times, and packed at 60°.
As a result of conducting a test to check the agglomeration state of the developer by placing it in a constant temperature bath for 24 hours, the developer of the present invention did not cause any aggregation, whereas the colored particles agglomerated and formed blocks. .

When we investigated the environmental dependence of the fluidity of the above charging characteristics, the developer of the present invention showed no change at all, but the above colored particles showed a decrease in band tt in humid conditions (80%R) 1 or more). The angle of repose also increased.

FIG. 2 is a schematic diagram of a one-component non-magnetic developing device, in which 1 is a developer carrier, 2 is a stirring blade, 3 is a hopper, 4 is a bias power source, 5 is an elastic blade, and 6 is a developer.

On the opposite side of the developing device 11Vc is placed a photosensitive body 8 having a latent image on its surface. The conditions for the device are a latent image of 15 oov and a bias of +200V.

Photoreceptor peripheral speed 12Qm/Sec, developer carrier peripheral speed 8
At 0 m/see, the gap between the photoreceptor 7 and the developer carrier 1 is 200 μm.

When the developer of the present invention was put into the above-mentioned developing device and tested, an extremely uniform thin layer was easily obtained, and uniform charging was achieved by utilizing the friction between the elastic blade 5 and the developer carrier L. A high-quality image with almost no Capri density unevenness was obtained.

Further continuous development? The result was approximately 100°000
No filming occurred on the developer carrier and the g-photo element even though the operation VC%1 was performed more than once. When the same procedure was performed on the colored particles, a uniform thin layer could not be obtained, and [%] was not sufficient, resulting in low-quality images with many uneven density, image omissions, fog, etc. After about 10,000 operations, filming was also observed.

Example 2 30 parts by weight of Boristine 1/N (Esso Petrochemical D-150) and styrene-butadiene copolymer (Nippon Zeon 2)
007J) and 10 parts by weight of carbon black (Colombian Raven 40) in a mixer.
After mixing, the mixture was passed through three rolls 3 to 5 times and kneaded.

After cooling, the mixture was coarsely crushed using a hammer mill and classified using a Type 1 mill (Japan Pneumatic) to obtain colored particles with an average particle size of 10 μm.

These colored particles are for heat roll fixing and have a softening point of 200°C.
This shows the above (ring & ball method).

When the charging characteristics and fluidity were measured in the same manner as in Example 1, the amount of charging was low at about 8 μC, and the angle of repose was 450, indicating very poor fluidity.

Next, the colored particles were coated with hydrophobic silica (Japan Axo
Sil R972) Th 1. As a result of adding 0% and applying a warning blender to improve the fluidity in the conventional manner, the angle of repose was 350, which was used as a comparative sample 7j.

Therefore, the developer of the present invention could be prepared using the above-mentioned colored particles.

First, a polymer of 7-containing acrylic ester (Daikin Industries, Ltd., polydimethyltetrafluoroglobulin methacrylate, softening point tso'c) was granulated to form beads of about 5 m.

The beads of the fluorine-containing acrylic ester polymer and the colored particles were placed in a ball mill and stirred for about 48 hours, and then taken out and sieved to remove all the beads of the fluorine-containing acrylic ester polymer, and the particles were mechanochemically removed. Fluorine acrylic acid ester polymer fine powder was attached to the surface of the colored particles.

Next, in the same manner as in Example 1, a fine powder of a fluorine-containing acrylic ester polymer was melted at a hot air temperature of 1550'c in a thermoplastic particle spheroidizing device and fused to the surface of the colored particles to form the developer of the present invention. However, in this example, the developer is not spherical but has an irregular shape.

Therefore, the characteristics of the developed developer of the present invention were evaluated in Example 1.
As a result of measurement in the same manner as above, the charge amount was 24 μC, the angle of repose was 34°, there was no environmental dependence, stable and good images were obtained, and no filming was observed.

On the other hand, with a comparative sample containing hydrophobic silica, a good paint was obtained with good fluidity at the beginning, but after about 1000 repetitions, a ghost image began to appear, and the capri also became larger, and gradually The image density decreases and it becomes impossible to develop after about 2000 times.

It was observed that hydrophobic silica was detached and accumulated on the developer carrier, and this detached silica is thought to be the cause.

Furthermore, as a comparative sample, we also investigated a case in which only fine powder of fluorine-containing acrylic ester polymer was attached without heat treatment, but the above-mentioned hydrophobic silica was added and the result was the same as in the next case.Example 3 Styrene-acrylic Copolymer resin (Sanyo Kasei TB 10
00) 90 parts by weight and 7 talocyanine blue organic pigment C,
1,74260 (Dainippon Ink First Genple)
5007) A 20-layer vertical section was kneaded using a pressurized kneader, pulverized and classified into two parts to obtain cyan particles with an average particle size of 15 μm.

About 0.2% by weight of fluorine-containing acrylic acid ester (Daikin Industries, Ltd. polyhexafluorobutyl methacrylate) fine powder in this cyan particle? When the developer of the present invention was fused, a cyan developer with good charging characteristics of 28 μc/fr and fluidity (angle of repose of 30°) was obtained. When developed in the same manner as in Example 1, it was transparent. Sexy 1
A high quality color image was obtained.

Although the present invention has been described above based on examples, the present invention can also be used as a good one-component magnetic developer by incorporating magnetic powder into colored particles, and furthermore, it can be used as a carrier, etc. ? It is also sufficient as a two-component developer. Copolymers of fluorine-containing acrylic esters and other general polymers [e.g. acrylic esters/methacrylic esters, styrene, vinyltoluene, α-
Those with vinyl groups such as methylstyrene 177? Also available.

[Brief explanation of drawings]

Charging characteristics in Figure 1? The comparative diagram shown in FIG. 2 is a sectional view of a main part of a developing device based on a one-component non-magnetic developing method in which the developer of the present invention is used.

Claims (1)

[Claims] Or halogen, CnH1n+, in which two or more hydrogen atoms are replaced with fluorine atoms, or chlorine and fluorine atoms, where n is an integer of 1 to 18. An electrophotographic developer characterized in that fine powder of a polymer of a fluorine-containing acrylic ester represented by the following formula is completely fused. (2) O% pestle claim, characterized in that the particle size of the fine powder of the fluorine-containing acrylic ester polymer is one or less of the particle size of the particles in which the colorant is dispersed in the binder resin. The electrophotographic developer according to item 1. (3) Electrophotography according to claims 1 and 2, characterized in that the polymer of the fluorine-containing acrylic ester has a softening point or melting point in the range of 60°C to 200°C. developer.