JPS5857103B2 - dry developer powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure fixable dry developer powder used in electrophotography, electrostatic printing, electrostatic recording, magnetic printing, and the like.

The pressure fixing method uses a means of passing the recording material carrying the developer powder image between a pair of pressure-loaded rollers and fixing it. It can be used immediately after turning on the switch, and does not pollute the environment. There are no problems such as this (and it is said to be advantageous in that everything is fixed completely when operated continuously at high speed.

However, the dry developer powder (
Developer powder (sometimes simply referred to as developer powder) is unsatisfactory because it causes various troubles either by itself or during the manufacturing process.

For example, JP-A-48-71648, JP-A-48-
The microcapsule toner powder disclosed in Japanese Patent No. 75032 is limited by both the triboelectric charging tendency of its coating resin with carrier particles and the manufacturing technology.

To overcome these drawbacks of the dry developer powder for pressure fixing, a developer powder composed of a wax component, a thermoplastic resin, a magnetic powder, and a colorant has been proposed.

According to this method, image density and storage stability can be satisfied, but the wax component and thermoplastic resin undergo phase separation during the manufacturing process of the developer powder, making it impossible to obtain the developer powder by easy means. There are some dislikes.

An object of the present invention is to provide a dry developer that can be easily and inexpensively produced, has excellent fixing properties and provides high image density, can be usefully and safely applied to high-speed copying or printing equipment, and has good storage stability. The purpose is to provide powder.

That is, the present invention comprises 95 to 70 parts by weight of a wax having a melting point of about 35 to 160'C, and 5 to 30 parts by weight of a filler having an average particle size of 5 microns or less, and having a particle size of 0.1 to 2. 5μ
This is a dry type developer powder containing 25 to 75% by weight of the magnetic material based on the total weight of the developer powder.

The developer powder of the present invention can contain a colorant.

The wax component used in the present invention preferably has a melting point in the range of about 35 to 160°C in order to impart good fixing properties to the toner, and all known wax components can be used, but examples include paraffin wax. , crystalline waxes, natural or synthetic aliphatic waxes such as carnauba wax, montan wax, ceresin wax and sugarcane wax, fatty acids such as palmitic stearate and behenic acid, fatty acids such as lithium stearate, aluminum stearate, barium stearate, zinc palmitate, etc. Metal salts, amide hydroxy waxes such as N(β-hydroxyethyl)-ricinolamide, N-N'-ethylene-bis-ricinolamide, N・N'-ethylene-bis-1,2-hydroxystearylamide, ethylene homo Examples include polymers, dicyclohexyl phthalate, diphenyl phthalate, hydroxystearic acid, and ethylene glycol monohydroxystearate.

Two or more of these wax components may be used at the same time, but the appropriate amount is 95 to 70 parts by weight based on the filler.

Further, as the magnetic material used in the present invention, for example, iron powder,
Examples include triiron tetroxide powder, iron sesquioxide powder, chromium powder, chromium dioxide powder, and nickel powder.

Two or more of these magnetic substances may be used at the same time, but the appropriate amount thereof is 25 to 75% by weight of the total weight of the developer powder.

In addition, the particle size of these magnetic substances is suitably about 0.10 to 2.5 microns.

If a toner is prepared by simply dispersing a magnetic material in the wax component described above, the toner will cause phenomena such as aggregation and bridging, and the fixed toner image will easily come off when rubbed with a finger.

This phenomenon occurs because the hardness of the wax component is lower than that of the thermoplastic resin normally used in heat fixing toners.

However, by adding a filler such as Mg or Ca carbonate, oxide, hydroxide, or silicate having an average particle size of 5 μm or less, such undesirable phenomena can be prevented.

Therefore, in the present invention, these fillers are present in an amount of 5 to 30 parts by weight based on the Fuchs component.

If the amount is less than 5 parts by weight, the effect will be poor, and on the contrary, developer powder added in excess of 30 parts by weight will not be fixed.

Examples of these fillers include calcium carbonate, magnesium carbonate, magnesium hydroxide, barium sulfate, calcium sulfate, magnesium oxide, talc, magnesium silicate, and calcium silicate, with magnesium carbonate and calcium carbonate being particularly preferred.

These are particularly preferable because they are mixed with other components in a heated molten state during the production of the developer powder of the present invention, and do not undergo any decomposition or change in quality even when pulverized.
This is probably because it does not deteriorate the electrostatic properties of the obtained developer powder.

The filler contained is effective in maintaining the shape of the produced developer powder and preventing agglomeration.

The developer powder composed of the wax component, filler, and magnetic material described above has a considerable image density, but if a developer powder with even higher density is desired, a coloring agent may be added. Bye.

Coloring materials include conventional pigments or dyes used in the art, such as carbon black, aniline black, channel black, acetylene black,
Examples include pigments such as lamp black, dyes such as Victoria Blue, Furnal Blue, permanent flutners, and nigrosine bases.

The blending amount of these colorants is 2 to 10% of the total weight of the developer powder.
It is appropriate to account for % by weight.

Further, in order to further improve the fluidity of the developer powder as described above, it is preferable to attach fine particulate inorganic pigments to the surface.

Accordingly, another aspect of the present invention includes 95 to 70 parts by weight of a wax having a melting point of about 35 to 160°C, and 5 to 30 parts by weight of a filler having an average particle size of 5 μm or less, and further contains 95 to 70 parts by weight of a wax having a melting point of about 35 to 160° C. .1
It is a dry developer powder with a particle size of 1 to 30μ, which is made by attaching a fine particulate inorganic pigment to the surface of a powder containing a magnetic material of ~2.5μ in a ratio of 25 to 75% by weight based on the total weight of the powder. .

Inorganic pigments used here include, for example, titanium oxide, silicon oxide (silica), molybdenum oxide, zinc oxide,
Examples include carbon black and talcum powder, and the particle size thereof is 0.1 μ or less, preferably 0.01 μ or less.

The developer powder of the present invention is as described above, but in order to actually produce it, a predetermined amount of wax components, fillers,
The magnetic material and, if necessary, a coloring material are mixed, and this is melt-kneaded at 150 to 170°C with a hot roll mill, then cooled, crushed with a hammer mill, and further finely crushed with a jet mill to obtain a particle size of 1 to 30μ. All you have to do is get it.

Alternatively, the powder thus obtained may be mixed with an inorganic pigment powder in an atmosphere slightly lower than the melting point of the wax component used therein, and excess inorganic pigment powder may be removed using, for example, an air classifier.

In this case, the pigment fine powder is firmly attached to the surface of the powder containing wax and filler.

In addition, the amount of adhered pigment powder is the total weight excluding it 1
A suitable amount is 0.5 to 2 parts by weight per 00 parts.

The developer powder of the present invention thus obtained fully satisfies the intended purpose.

Next, examples and comparative examples will be shown.

Note that all parts are parts by weight.

Comparative example Aluminum stearate 100 parts Iron oxide
A mixture of 100 parts and 20 parts of carbon black was melted in a heated roll mill at 150-170°C for 30 minutes.

After cooling, this was coarsely pulverized with a hammer mill and further finely pulverized with a jet mill to produce a comparative developer powder having an average particle size of 18 μm.

When copying was carried out using this developer powder in a commercially available zinc oxide type pressure fixing copying machine, it was observed that the fixed image smeared when rubbed with a finger.

Example 1 Ammonium stearate 80 parts iron oxide
A compound consisting of 100 parts carbon black, 20 parts, and 20 parts calcium carbonate was subjected to the same operation as in the comparative example to obtain a developer powder (product 1 of the present invention) having an average particle size of 15/J.

Next, this was also subjected to copying in the same manner.

On the other hand, a developer powder - comparative product A- was prepared using 20 parts of iron oxide instead of 20 parts of calcium carbonate in the above formulation (ie, 120 parts of iron oxide), and was subjected to copying in the same manner as in the comparative example.

Furthermore, in the above formulation, 100 parts of calcium carbonate was used instead of 100 parts of iron oxide (i.e., 12 parts of calcium carbonate was used).
0 parts) Developer powder - Comparative product B- was prepared.

Next, after uniformly scattering this developer powder (comparative product B) on the sheet, it was positively charged by corona discharge, and a zinc oxide photoreceptor having a latent image was brought into contact with it to develop it.
The pressure was established.

Next, a blank sheet of paper was placed on top of each developed image (copy image), and a 3 kg press rod with a rubber tip fixed on top of the sheet was placed on top of each developed image (copy image).
Press down with a pressure of c4, pull the image-bearing photoreceptor (image-bearing recording material) while fixing the position of the white paper against the press rod, and measure the toner transferred onto the white paper (transferred toner) with a Macbeth fist meter. When the fixing properties were investigated, the results shown in Table 1 were obtained.

From this, it was confirmed that the image fixing properties of the developer powder of this example were excellent.

Example polyethylene wax 80 parts iron oxide
A mixture consisting of 100 parts spirit black, 5 parts magnesium oxide, and 20 parts was subjected to the same operation as in the comparative example to obtain a developer powder (inventive product 2) having an average particle size of 18 μm.

Next, this was also subjected to copying in the same manner.

On the other hand, developer powder - comparative product C- was prepared using 20 parts of iron oxide instead of 20 parts of magnesium oxide in the above formulation (ie, 120 parts of iron oxide), and was subjected to copying in the same manner as in the comparative example.

Additionally, a comparative developer powder was prepared using 100 parts of magnesium oxide instead of 100 parts of iron oxide in the above formulation (i.e., 120 parts of magnesium oxide).

Next, this comparative product was subjected to pressure fixing in the same manner as comparative product B in Example 1.

Subsequently, the fixability of each developed image (copied image) was examined in the same manner as in Example 1, and the results shown in Table 2 were obtained.

From this, it was confirmed that the image fixing properties of the developer powder of this example were excellent.

Example 3 1.5 parts of carbon black (particle size 0.02.z) was added to 100 parts of the developer powder obtained in Example 2 and mixed in a ball mill at about 150°C to coat the surface with inorganic Another developer powder was made that had pigment attached to it.

This developer powder showed no agglomeration at all.

Further, the fixed image obtained using the same showed good results as in Example 1.

Claims (1)

[Claims] 1 Wax 95-70 having a melting point of about 35-160°C
part by weight, and 5 to 30 parts by weight of filler with an average particle size of 5 μ or less, and 25 to 75 weight % of magnetic material with a particle size of 0.1 to 2.5 μ based on the total weight of the developer powder. A dry developer powder with a particle size of 1 to 30 μm. 2 Wax 95~ with a melting point of about 35~160'C
70 parts by weight, 5 to 30 parts by weight of filler with an average particle size of 5 μ or less, and a magnetic material with a particle size o of 1 to 2.5 μ in a proportion of 25 to 75 weight % based on the total weight of the powder. A dry developer powder having a particle size of 1 to 30 μm and having a finely divided inorganic pigment attached to the surface of the powder.