JPS61172155A - Positively chargeable toner - Google Patents

Abstract

PURPOSE:To reduce a change in the extent of electrostatic charge of a toner with the lapse of time and to inhibit the scattering of the toner by using a positively chargeable thermoplastic resin having positive chargeability or a positively chargeable thermoplastic resin provided with positive chargeability by adding a charge controller and a white or colorless quat. ammonium salt. CONSTITUTION:This toner contains a positively chargeable thermoplastic resin having positive chargeability or a positively chargeable thermoplastic resin provided with positive chargeability by adding a charge controller and a white or colorless quat. ammonium salt. The thermoplastic resin having positive chargeability may be a thermoplastic resin having amino groups. The charge controller for providing positive chargeability to a thermoplastic resin may be a compound having an amino group. The thermoplastic resins have preferably about 5,000-30,000 number average mol.wt., and the proper dielectric constant is >=3.0 in a dry state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to toners used for developing electrostatic latent images.

Prior Art Conventional toner for developing electrostatic latent images is produced by blending a coloring agent with a chargeable thermoplastic resin to which a charge control agent has been added as needed, cross-melting it, and then finely pulverizing it to obtain the desired shape. Those classified by size are used.

This toner produces clear developed images without fogging etc. -Rokukowo-LM is being scolded. Furthermore, it is also required that the amount of charge does not change over time, and that the amount of charge does not change significantly, such as attenuation or solidification, due to environmental changes, such as changes in humidity. This is because when the amount of charge attenuates from the initially set value and becomes smaller, toner scattering increases, causing problems such as background fog, toner scattering on blank areas, and toner stains inside the copying machine. It is.

In order to meet the above requirements, various proposals have been made regarding thermoplastic resins to be used. For example, in order to adjust the amount of charge of toner, it has been proposed to use chargeable thermoplastic resins that have various polar groups, or use chargeable thermoplastic resins that have been given chargeability by adding a charge control agent. However, the current situation is that there are still various problems.

Problems to be Solved by the Invention It is an object of the present invention to provide a positively charged toner in which the amount of charge changes less with time and is less likely to cause toner scattering.

Means for Solving the Problems The present invention uses a positively charged thermoplastic resin, or a positively charged thermoplastic resin that has been given positive chargeability by adding a charge control agent, and a white or colorless quaternary class resin. The present invention relates to a positively charged toner containing an ammonium salt.

As mentioned above, the toner mainly consists of a colorant and a thermoplastic resin, to which various additives are added or surface treatments are applied, if necessary.

In the present invention, by adding and blending a white or colorless quaternary ammonium salt as a charge amount stabilizer to the toner, the change in charge amount over time is improved, the attenuation of the charge amount is reduced, and as a result, toner scattering. It is characterized by the fact that the occurrence of such problems is significantly suppressed.

The thermoplastic resin used in the present invention is a positively charged thermoplastic resin that itself shows positive chargeability, or is a positively charged thermoplastic resin that has been given positive chargeability by adding a charge control agent. Typical examples of those exhibiting this include thermoplastic resins having amino groups. Furthermore, typical charge control agents that impart positive chargeability to thermoplastic resins include those having an amino group.

However, it is not limited to these.

Thermoplastic resins that can be used in the present invention include styrene resins, styrene-acrylic copolymer resins, polyester resins, epoxy resins, mixed resins thereof, and those having amino groups in their alkyl side chains. There is. Specifically, styrene-based resins such as polystyrene and polyvinyltoluene, and these and various acrylics,
Further examples include copolymer resins with methacrylic esters, and further include bisphenol type, rosin glycidyl ester type, and polyethylene terephthal type polyester resins.

These resins have a number average molecular weight of 5,000 to 30°000.
It is preferable that the relative dielectric constant under dry conditions is about 3.
A value of 0 or more is appropriate.

Two or more types of resins may be blended, and resins having and not having positively charged properties may be blended appropriately.

When used as a non-magnetic toner, the amount of resin blended in the toner is 60 to 99% by weight, more preferably 80 to 98% by weight, based on the total weight of the toner.

Examples of the above amino group include -NH, -NHCH3,
N(CH3)2, NHCtHs, 'N(C2H
5)! , NHCHtCHtOH,N(CtHtOH)
, -N(CH3)CH, CH, OH1, etc., and the positively charged thermoplastic resin having an amino group is a saturated or unsaturated hydrocarbon having the general formula: %1 to 8. ” can be preferably used.

If the above-mentioned resin does not have a polar group such as an amino group and does not have positive chargeability itself, or if the chargeability itself is insufficient, use a charge control agent as a positively charged resin containing a polar group such as an amino group. It is necessary to add a control agent, such as a nigrosine oil-soluble dye, to the resin to impart desired positive chargeability to the resin.

In this case, the charge control agent is 0.1-15% by weight of the total amount of resin.
, more preferably 1 to 10% by weight. Many charge control agents can function as colorants in some sense, and therefore it is difficult to add a colorant to the toner, especially if the resin already has the desired color tone due to the addition of the charge control agent. There is no need to mix them. In addition,
When the resin itself has sufficient positive chargeability, a charge control agent for the resin is not necessarily required.

The quaternary ammonium salt as a charge stabilizer used in the present invention has the general formula: and X represents a halogen, a sulfonic acid group, a sulfonic acid ester group, a sulfuric ester group, or an alkyl sulfuric ester group], and is particularly white or colorless.

The above-mentioned quaternary ammonium salts may be selected from those that do not have deliquescent properties and have low water solubility and moisture absorption.
It is preferable that the melting point (m, p,) is 100°C or higher and the decomposition point is 200°C or higher.

The amount of quaternary ammonium salt added depends on its molecular weight, but it is usually 0.1 to 0.1 of the total amount of toner! 0% by weight, more preferably 0.5 to 5% by weight. If it is less than 0.1% by weight, the effect of the present invention cannot be obtained, and if it is more than 10% by weight, the dispersibility decreases and the environmental stability worsens.

Examples of colorants that can be added as needed in the present invention include black pigments such as carbon black, such as furnace black, channel black, and acetylene black; examples of red colorants include Lysol Red, Watching Red, Carmino 6B, and Lake Red. C1 chromophthal red, etc., blue colorants include Cu-phthalocyanine, green colorants include chlorinated or brominated CU-phthalocyanines, yellow colorants include benzidine yellow, hanza, etc. yellow, chromophthal yellow, etc.

Incidentally, inorganic pigments include titanium white and zinc white for white, and iron black and cupric oxide for black pigments, but both organic and inorganic pigments can be used as long as they are non-polluting and have high coloring power. However, it is not limited to these.

The toner of the present invention may further contain other additives, such as waxes, if necessary, or may be surface-treated with ultrafine metal oxide powder.

The toner of the present invention can be formulated with a suitable carrier, for example.
It can be used as a component developer. As the carrier, resin-coated glass beads, steel balls, etc. are used when implementing the cascade development method, and ferrite, fine iron powder, or so-called binder type microcarriers are used when implementing the magnetic brush development method. Further, the toner of the present invention itself may be manufactured as an insulating magnetic toner, and a magnetic brush development method may be implemented using this as a one-component developer.

Furthermore, it may be used as a toner when carrying out an impression development method or a touch-daum development method. - Example 1 (Combination of amine charge control agent and white quaternary ammonium salt) 5 parts by weight of charge control agent (Bontron N-01: manufactured by Orient Chemical Industry Co., Ltd.) 2 parts by weight of wax (Viscol 330P: manufactured by Sanyo Chemical Co., Ltd.) (manufactured by Orient Kagaku Kogyo Co., Ltd.): 2.5 parts by weight or more of the raw materials (manufactured by Orient Chemical Industry Co., Ltd.): After thoroughly mixing 2 parts by weight or more of the raw materials in a Henschel mixer, kneading in a twin-screw kneader, cooling, and coarsely pulverizing. , then crushed and classified using a jet crusher and a wind classifier to obtain a particle size distribution of 5 to 25 μm.
, with an average particle size of 13.0 μl. After that, Aerosil R972 (Nippon Aerosil Co., Ltd. refined water-based silica)
0.2% by weight was mixed to prepare toner 1.

Example 2 (Combination of amino group-containing resin and white quaternary ammonium salt) A toner having the same particle size was produced in the same manner as in Example 1 using 2 parts by weight of Viscol 330P. This is referred to as toner 2.

Example 3 (Combination of resin having amino group and white quaternary ammonium salt) Thermoplastic styrene/amyacrylic resin: (Mn=13
．． 400. Mw/Mn= 16.5゜Amine value=4LK
OHR9/9”) 100 parts by weight Copper phthalocyanine blue (Fastogen Blue TGR: manufactured by Dainippon Ink and Chemicals Co., Ltd.): 3 parts by weight Wax (Viscol 330P: manufactured by Sanyo Chemical Co., Ltd.): 2.5 parts by weight 4th A toner having the same particle size was produced from 2 parts by weight of ammonium salt (Bontron P-51) in the same manner as in Example 1. This is referred to as Toner 3.

Example 4 (Combination of amino group-containing resin and white quaternary ammonium salt) Example 3 except that a thermoplastic styrene/amino acrylic resin with an amine value of 10 K OHM 9/9 was used.
Toner 4 having the same particle size as the toner was prepared in the same manner.

Examples 5 to 10 Toner 5 was prepared in the same manner as in Example 3, except that the amount of quaternary ammonium salt (P-51) added was changed as shown in Table 1.
I got ~10. All of these toners have the same particle size as Toner I.

Example 11 Toner 11 was prepared in the same manner as in Example 3 except that tetramethylammonium iodide salt (m, p, white at 230° C.) was used as the quaternary ammonium salt.

Toner 12 was prepared in the same manner as in Example 3, except that tetraethylammonium iodide salt (m, p, color of 200° C. or higher) was used as the quaternary ammonium salt.

Example 13 Toner 13 was prepared in the same manner as in Example 3, except that triethylbenzylammonium chloride (m, p, color of 200° C. or higher) was used as the quaternary ammonium.

Example 14 Toner 14 was prepared in the same manner as in Example 3, except that phenyltrimethylammonium iodide salt (m, p, white at 175° C.) was used as the quaternary ammonium salt.

Comparative Examples A and B (Example using a resin that does not have positive chargeability) Bontron N-01, which is the raw material used in Example 1 and is added to the resin as a charge control agent that imparts positive chargeability to the resin.
The composition was the same as in Example 1 except for , and the composition was designated as toner A.

Toner B was prepared using the same composition as in Example I except for the raw materials used in Example 1 except for Bontron N-01 and Bontron P-51.

Comparative Example CF (example without using quaternary ammonium salt) Toner CF was prepared in the same manner as in Examples 1 to 4 except that Bontron P-51 was not used.

Experimental Example 1 110 parts by weight of toner and binder type microcarrier (
Prioride ACL (00 parts by weight worn by Gutsdoyer,
200 parts by weight of Mapico Black 500 (manufactured by Titanium Industries, Ltd.), Carbon Black MA#8 (manufactured by Mitsubishi Kasei Corporation)
4 parts by weight, silica #2°O (manufactured by Nippon Aerosil Co., Ltd.)
A developer is prepared by mixing 90 parts by weight of a magnetic carrier having a composition of 2 parts by weight and an average particle size of 40 μm,
A copy image was formed on transfer paper using EP450 (manufactured by Minolta Camera Co., Ltd.). The resulting image had little fog, good texture in halftone areas, and good overall image quality. Further, there was no change even after a 30,000-sheet printing test. In addition, the amount of charge, toner scattering,
and environmental stability (attenuation rate of charge amount) were measured.

The amount of charge indicates a value determined from the results of developing a charged insulating film using toner and measuring the amount of decrease in surface potential of the film and the amount of toner attached to the film.

To check the scattering of toner, remove only the developing device from the copying machine.
When the developing device was operated for a certain period of time, toner scattered from the developing device was caught on a blank sheet of paper, and the amount of toner was visually observed and evaluated. The results were evaluated as ◎, ◯, △, and × in descending order of scattering.

The attenuation rate is the initial charge amount at room temperature and humidity, and the
Charge amount ratio (%) after storage for 2 days in an environment of 85RH%
: Represented by . Practically speaking, it is desirable that the attenuation rate is 20% or less.

The test results are shown in Table-1.

Experimental Examples 2 to 14 Developers were prepared using the toners obtained in Examples 2 to 14 in the same manner as in Experimental Example 1, and tests were conducted in the same manner as in Experimental Example 1 using the developers.

No matter which toner was used, the images had little fog, good texture in halftone areas, and were well-defined throughout the image.

Note that the results of the 30,000-sheet printing durability test of the developer using Toner 3 were good. No printing tests were conducted on other toners.

Comparative Experimental Examples A to F In the same manner as in Example I, a developer was prepared using the toners obtained in Comparative Examples A to F, and the same copying test as in Example 1 was conducted. The results obtained are shown in Table-1.

In addition, with the developer using Toner A or B, the amount of charge of the toner itself was low, and development was not possible (development density was low).
. Furthermore, when toner C-F was used, significant fogging already occurred after copying 1000 sheets, making it unusable for practical use.

Table 1 From the results of Comparative Examples A and H in Table 1, it is understood that the charge amount stabilizer used in the present invention does not have the function of imparting positive chargeability to the resin itself.

As is clear from the comparison between Examples and Comparative Examples, the charge amount stabilizer significantly improves the attenuation rate of charge amount, toner scattering, and the like.

Effects of the Invention The positively charged toner of the present invention shows little change in charge amount over time;
Excellent printing durability. Furthermore, there is no toner scattering, so background fogging is less likely to occur, and there is less toner staining on the blank portion of the copy paper and less toner staining inside the copying machine.

Claims (1)

[Claims] 1. A positively charged thermoplastic resin containing a positively charged thermoplastic resin or a positively charged thermoplastic resin that has been given positive chargeability by adding a charge control agent, and a white or colorless quaternary ammonium salt. toner.