JPH11327193A - Color toner wax - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide color toner excellent in a fixing characteristic at a low temperature without damaging transparency, in offset resistance, and in blocking resistance by containing a specified hydrocarbon wax in the toner. SOLUTION: This is a wax to be used as a separation agent mixed in an electrophotographic color toner, using as its fixing resin stylene-ester acrylate copolymer, and is composed of hydrocarbon wax having an average carbon number of 30-40. Preferably its melting point is 60-90 deg.C and its melting start temperature of DSC measured by a differential scanning calorimeter is not less than 50 deg.C. Thermal coagulation occurs in the case of average carbon number of 30 or less and the DSC melting starting temperature of 50 deg.C or less so that a powder fluidization characteristic decreases. When the hydrocarbon wax is contained in the range of 1-10 pt.wt. in 100 pts.wt. of fixing resin, transparency is not damaged and separation characteristic at the time of fixing by a heating roller is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wax as a release agent for a color toner for electrophotography.

[0002]

2. Description of the Related Art Conventionally, in electrophotographic toners for copying machines and printers, there has been a demand for speeding up the copying machine and saving energy. To cope with this, development of a toner having excellent low-temperature fixability has been demanded, and various studies have been made so far. Further, among toners for electrophotography, the hot roll fixing method has been attracting attention as an effective fixing method in that it has good thermal efficiency and can fix quickly.

However, in this method, when an image is fixed with a heating roller or the like, a so-called offset phenomenon occurs in which a part of the electrostatic toner adheres to a heating body and stains a next copy sheet. Was inevitable. In the past, various means for preventing such a phenomenon have been studied, and in practice, a method of adding a low-molecular-weight polyethylene wax, a low-molecular-weight polypropylene wax, or the like to impart toner releasability to the toner has been proposed. Used. However, when these release agents are used, there remains a problem that the transparency of the color toner is hindered and the low-temperature fixability is reduced. Also, when fixing with a heated roller, the roller surface is impregnated with silicone oil or supplied with silicone oil to improve the transparency of the color toner and eliminate the offset phenomenon. Stickiness on paper and equipment become complicated and cost increases.

Further, Japanese Patent Application Laid-Open Nos. 7-219274 and 9-2
Although 69609 and the like propose color toner itself, the fact is that the wax of the release agent has not been sufficiently studied and no attempt has been made to devise the transparency of the color toner. In view of the above problems of the prior art, an object of the invention of the present application is to provide a wax for a color toner which has good releasability and excellent transparency.

[0005]

Means for Solving the Problems In view of the above-mentioned current state of color toners, the inventors of the present application have conducted various studies on color toners having excellent releasability and transparency, and have found that hydrocarbon wax is used as an essential component. Was found to be particularly effective, and the present invention was completed.

That is, the invention of the present application is to solve the problems of the prior art, and to provide a wax as a release agent to be blended in a color toner for electrophotography using a styrene-acrylate copolymer as a fixing resin. And
Provided is a wax for electrophotographic color toner, comprising a hydrocarbon wax having an average carbon number of 30 to 40.

The invention of this application has a melting point of 60-9.
The present invention also provides the wax, wherein the wax has a melting temperature of 50 ° C. or higher at 0 ° C. and DSC by a differential scanning calorimeter. Further, the invention of this application also provides a wax for an electrophotographic color toner to be blended in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of a fixing resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application provides a wax for a color toner having the above-mentioned features. More specifically, the hydrocarbon wax of the present invention has an average carbon The number is 30-40.
More preferably, the wax is a wax having a melting point of 60 to 90 ° C. and a melting start temperature of DSC of 50 ° C. or more by a differential scanning calorimeter. Average carbon number of 30 or less and DSC
If the melting start temperature of the powder is 50 ° C. or lower, thermal aggregation occurs, and the powder fluidity decreases, which is not preferable. When the average carbon number exceeds 40, the transparency of the fixing resin is reduced.
Not preferred.

When the hydrocarbon wax is contained in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the fixing resin, transparency is not impaired, and the releasability at the time of fixing by a heating roller is improved. . Examples of such hydrocarbon waxes include paraffin wax, microcrystalline wax, Fischer-Tropsy wax, low molecular weight polyethylene wax and the like.

[0010] Specific examples of the hydrocarbon wax include paraffin wax such as HNP-1 and HNP manufactured by Nippon Seiwa.
-9 and HNP-11, and FT-0165 manufactured by Nippon Seiswa is exemplified as the Fischer Tropical wax. Each wax has an average carbon number of 30 to 40 and a melting point of 60 to 90 ° C., and is measured by DSC using a differential scanning calorimeter.
Is a wax whose melting start temperature is adjusted to 50 ° C. or higher.

The fixing resin to which the wax of the present invention is blended is a styrene / acrylate copolymer, specifically, a styrene / acrylic acid copolymer or a styrene / diethylamino / ethyl methacrylate copolymer. Styrene / butadiene / acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / glycidyl methacrylate copolymer, styrene
Examples thereof include butyl methacrylate / maleic anhydride copolymer and styrene / butyl methacrylate / acrylic acid copolymer.

The mixing ratio of the styrene / acrylate copolymer and the hydrocarbon wax is preferably 1 to 10 parts by weight of the hydrocarbon wax with respect to 100 parts by weight of the styrene / acrylate copolymer. It is said. When the amount of the hydrocarbon wax is less than 1 part by weight, the toner easily adheres to the heating roller, and when the amount is more than 10 parts by weight, the transparency of the fixing resin decreases, which is not preferable.

A coloring agent can also be compounded with the wax, and commonly used pigments can be used. Pigments include carbon black, Hansa YellowG, Hansa Yell
ow5G, Disazo Yellow, Tartrazine Yellow Lake, La
ke RedC, Carmine 6B, PhloxineRed, Quinacridone
s, Phthalocyanines, Indanthrene Blue, molybdung tungstophosphoric acid, disazo yellow, carmine 6B, copper phthalocyanine, nigrosine dye, aniline dye, chrome yellow, ultraman marine blue and the like.

[0014]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples. (Example 1) Styrene-butyl methacrylate copolymer (Hymer SBM-73F, manufactured by Sanyo Chemical Industries) 100
The hydrocarbon wax shown in Table 1 (HNP-9 average carbon number 37, melting point 75 ° C) 3
Parts by weight using a Henschel mixer at 3000 rpm
And after mixing the powder for 1 hour, use a plast mill at 150 ° C
For 1 hour. Further, the sample was subjected to vacuum degassing for one hour and cooled to obtain a sample for a transparency test. Further, 2 parts by weight of a copper phthalocyanine pigment and 2 parts by weight of a zinc salt of a salicylic acid derivative were added to the above mixture, and the mixture was added to a plastmill to give 150 parts.
And kneaded for 1 hour. After natural cooling and coarse pulverization with a cutter knife, the kneaded product was pulverized with a jet pulverizer, and a base toner having a particle diameter of 5 to 15 μ was obtained using an air classifier. Furthermore,
One part by weight of colloidal silica was added thereto and mixed with a mixer to obtain an electrostatic toner.

Next, 6 parts by weight of an electrostatic toner is mixed with 100 parts by weight of iron powder (made by Nippon Iron Powder) having a particle size of 50 to 80 μm as a carrier and developed by a conventionally known electrophotographic method. Then, the image was fixed by heating at a constant temperature of 120 ° C. with a heating roller. The print after copying was evaluated for fixability, offset phenomenon, heating roller contamination, and the like. Table 2 shows the evaluation results. (Examples 2 to 4 and Comparative Examples 1 to 4) In the same manner as in Example 1, the type of the hydrocarbon wax was changed, and toner preparation and copy tests were performed. Table 1 shows the physical properties of the hydrocarbon wax, and Table 2 shows the evaluation results.

The evaluation tests of Examples 1 to 4 and Comparative Examples 1 to 4 were performed according to the following specifications. <Transparency test> The two-component melt-kneaded product of the fixing resin and the hydrocarbon wax obtained in the examples was poured into an aluminum cup, cooled and molded to a thickness of 10 mm, and then subjected to a spectrophotometer (spectral colorimeter manufactured by Minolta). Using the CM-2022) ^.
(JIS Z 8722) was measured. The smaller the lightness L ^{*, the} better the transparency, and the larger the lightness L ^{*, the} poorer the transparency and whitening. <Blocking Test> 30 g of the electrostatic toner pulverized and classified by a jet pulverizer was placed in a 100 cc polycup, allowed to stand at 50 ° C. for 3 days, and the aggregation state of the toner at that time was evaluated by a sieving measuring instrument. <Melting start temperature of DSC> In a DSC curve measured by a differential scanning calorimeter (DSC-220 manufactured by Seiko Instruments Inc.), the temperature was raised from -30 ° C to 160 ° C at a rate of 5 ° C / min, and the melting curve at that time From this, the melting onset temperature was measured. The melting onset temperature is the intersection of the baseline and the tangent from the point of maximum displacement of the melting peak. Specific examples of the melting start temperature of DSC are shown in FIGS. <Fixability test> A real-image test was performed with the roller temperature of a commercially available electrophotographic copying machine set at 120 ° C, and the obtained fixed image was rubbed with a constant load, and the density reduction before and after rubbing was visually compared. did.

The roller temperature of a commercially available electrophotographic copying machine is set to 1
An actual test was performed at 20 ° C., and an offset test was performed. The offset was determined based on how the image was stained.

[0018]

[Table 1]

[0019]

[Table 2]

Usually, a high-crystalline release agent represented by polyethylene wax or polypropylene wax is used in a toner to improve the high-temperature offset property at the time of fixing. For OHP
The transparency of the toner image is hindered during output. On the other hand, it was confirmed that the hydrocarbon wax of the present invention had extremely excellent transparency as shown in Table 2, had no offset phenomenon to the heating roll, and had excellent low-temperature fixability.

[0021]

According to the invention of the present application, as described in detail above, by including a specific hydrocarbon wax in the toner, it is possible to impart favorable thermal characteristics to the toner. That is, it is possible to realize a color toner having excellent fixability at low temperatures, excellent anti-offset properties, and excellent blocking resistance without impairing the transparency of the color toner.

[Brief description of the drawings]

FIG. 1 is a view showing a DSC curve when a temperature of a wax as an example is raised.

FIG. 2 is a view showing a DSC curve when the temperature of wax as an example is raised.

FIG. 3 is a view showing a DSC curve when a temperature of a wax as a comparative example is raised.

Claims (4)

[Claims] 1. A wax as a release agent blended in a color toner for electrophotography comprising a styrene / acrylate copolymer as a fixing resin, wherein the wax has an average carbon number of 3.
A wax for an electrophotographic color toner, comprising 0 to 40 hydrocarbon waxes. 2. The wax for an electrophotographic color toner according to claim 1, wherein the wax has a melting point of 60 to 90 ° C. and a melting start temperature of DSC measured by a differential scanning calorimeter of 50 ° C. or more. 3. An amount of 1 to 100 parts by weight of the fixing resin.
3. The wax for an electrophotographic color toner according to claim 1, which is blended in an amount of 10 parts by weight. 4. An electrophotographic color toner comprising the wax according to claim 1.