JPS6337357A - Toner for dry heat fixing - Google Patents

Abstract

PURPOSE:To obtain the titled toner capable of preventing a hot offset and having a improved durability, without hindering various properties of the titled toner such as fluidity, etc., by incorporating a fine particle of polypropylene which is modified with carboxylic acid at an end-group of the molecule to the toner contg. a binding resin and a coloring matter. CONSTITUTION:The fine particle of the polypropylene which is modified with the carboxylic acid at the end-group of the molecule is the polypropylene homopolymer which does not contain a functional group and is modified with the carboxylic group at the end-group of the molecule, and has an acid value of 0.1-50 (KOH mg/g) and a number molecular weight of 500-20,000. The compounding amount of said fine particle is 0.1-5pts.wt., preferably 0.2-2pts.wt. per 100pts.wt. of the toner. Thus, as the fine particle of the low mol.wt. polypropylene which is modified with the carboxylic acid at the end-group of the molecule is added to the toner, so that the polypropylene exists on the surface of the toner, the titled toner capable of displaying immediately the hot-offset preventing effect by heating it at the time of fixing, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dry heat roller constant wear toner that prevents pot offset and has good heat fixability.

[Prior art] In electrophotography, an electrostatic latent image formed on a photoreceptor by charging and exposure is developed with a developer containing toner to form a toner image, and then transferred to a transfer sheet and further fixed. Ru.

Thermal fixing method is conventionally known as a fixing method, but in this method, the toner particles transferred onto the transfer sheet 1 are permanently fixed using a heated roller made of silicone, Teflon, etc. has the disadvantage of easily causing this 1-system hot offset. This phone 1~
- Off-sera 1- is a phenomenon in which when toner in a molten state comes into contact with a roller, the toner adheres to the roller surface, and this adhered toner adheres to the transfer sheet as the roller rotates.

As a method to solve this problem, a method has been proposed in which 2 to 10 weight parts of low-molecular weight polypropylene are kneaded into the toner per 100 weight parts of the toner base (see Japanese Patent Laid-Open No. 49-65231'?3). In this case, the polypropylene is exposed and aligned on the toner surface due to heating in the fixing section, so there is sufficient separation!・The prevention effect is 19%. If a large amount of low molecular weight polypropylene is mixed in to achieve this effect, the fluidity of the toner will drop significantly, making it unsuitable for practical use.

As a way to solve this 1) Kaimei 57-168253
In this issue, a method was devised in which fine powder of low-molecular omega-polypropylene was added to ordinary toner particles, but in this method, the low-molecular-weight polypropylene present on the surface of the toner particles was exposed to the surface of the carrier due to the heat and pressure caused by stirring the developer. This also has disadvantages in that so-called spent occurs, in which the developer is fused to the surface of the developing sleeve, and the durability of the developer is shortened.

[[1] The present invention is aimed at solving the above-mentioned conventional drawbacks, and firstly, it prevents hot offset and improves durability without impeding various properties such as toner fluidity. The present invention provides a dry heat fixing agent with improved properties.

[Structure] The present invention is a toner for dry heat fixing, which is characterized in that fine polypropylene powder whose ends are modified with carboxylic acid is added to a toner containing a binder resin and a colorant.

The fine powder of polypropylene modified with carboxylic acid at the terminal end used in the present invention is obtained by modifying the terminal end of a polypropylene homopolymer with no functional group with a carboxyl group, and has an acid value of 0.1 to 50 (0.1 m(]/ ll]) Preferably, those having a molecular weight of 0.5 to 10 (0.11 mg/c+) are used, and those having a molecular weight of 500 to 20,000, preferably 1,500 to 1000 are used.

The particle size of the polypropylene fine powder modified with carboxylic acid at the terminals is 5 μm or less, preferably 0.05 to 1.0 μm, and the amount added is 0.1 to 5 parts by weight, preferably 0.05 parts by weight, per 100 parts by weight of the toner. It is 2 to 2 parts by weight.

In the present invention, instead of kneading polypropylene into the toner as in the conventional method, a low molecular weight polypropylene fine powder whose ends are modified with carboxylic acid is added to the toner particles so that the polypropylene is present on the toner surface. , the hot offset prevention effect is immediately exerted by heating during fixing. Therefore, compared to kneading, it has a faster effect, requires less use, and does not impair the fluidity of the toner.

In addition, since this polypropylene is modified with a carboxylic acid at the terminal end, it firmly adheres to the i~ Lunar surface and does not migrate to the carrier surface or the sleeve surface, so that Spen 1~ does not occur.

Examples of the binder resin used in the present invention include polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, and styrene-chloride copolymer. Vinyl copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-edyl acrylate copolymer, styrene- butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate ester copolymer, styrene-methacrylate copolymer, styrene-methacrylate Styrene such as ethyl acid copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α-methyl chloroacrylate copolymer, and styrene-acrylonitrile-acrylic ester copolymer system resin (styrene or a monopolymer or copolymer containing a styrene substitute), vinyl chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenyl resin, epoxy resin, polyester resin, low molecular weight polyethylene, There are low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, Kane resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, etc., but these resins are not limited to single use, but can also be used in combination of two types. The above can also be used together.

Moreover, these manufacturing methods are not particularly limited, and any of tetramorphic polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.

Further, any coloring agent may be used as long as it is uniformly dispersed in the binder resin, and the color thereof is not particularly limited. Specifically, black colorants include carbon black, acetylene black, titanium black, etc., blue colorants include cobalt blue, phthalocyanine blue, cyanine blue, etc., and red colorants include red colorant, cadmium red, cadmium red, etc.
pigment red, solvent red, etc. Yellow coloring agents include chrome yellow, lyonol yellow, cadmium yellow, benzine yellow, permanent yellow, etc. Green coloring agents include chrome green, chromium oxide, malachite green, lyonol green, etc. Other colorants such as orange, purple, and white may also be used. Furthermore, a polarizing agent and the like can be added as necessary.

To disperse these colorants in the binder resin, the colorant and binder resin may be dispersed in advance using a mixer or the like, and then kneaded using a pressure kneader 1 heated Niki roll or the like.

Thereafter, it is cooled and solidified, and then crushed and classified to obtain toner particles.

Examples of the present invention will be described below.

Example 1 A toner having an average particle size of 10 μm was prepared using the following recipe. (Units are heavy parts) Polystyrene homopolymer (Esso, Picolastic [)-125) 90 parts Carbon black (Mitsubishi Kasei) 10 parts Next, fine polypropylene powder modified with carboxylic acid at the terminal (number average molecular weight 3500. Value 5.2
, average particle size 0.7μ) per 100 parts of the above toner.
The toner of the present invention was obtained by adding 100% and mixing in a Henschel mixer.

For comparison, the toners with the above formulation were (1) polypropylene-free toner (2) normal polypropylene (molecular ff 13500.
! Toner (3) in which O1 (addition amount: 2 parts) was kneaded during kneading.
An ordinary polypropylene fine powder (molecular ff 13,500, acid value O1 average particle size 0.7 μm, addition amount 2 parts) was prepared.

Using the above four types of toner, the hot offset generation temperature and the spen! - The amount of toner was measured. The results are shown in the table below. In the above test, the pot offset generation temperature was determined using a copying machine (■ Ricoh,
FT4040) to create an unfixed image. At this time, the amount of toner adhesion is controlled to be 1.0 mg/Cm2. This sample was passed between a 40φ Teflon roller and a 40φ silicone rubber roller at a rotational speed of 15 Or, p, m to determine the temperature at which hot offset begins to occur.

For the amount of Spen l-toner, 97 parts by weight of carrier (100 micron iron oxide powder) and 3 parts by weight of toner were placed in a 100 ml stainless steel pot and stirred for 24 hours. Then, it was calculated using the following formula.

Spent toner mother = ([(Carrier weight after blow-off) - (+- Chitria weight after dissolving toluene)] / Carrier weight after blow-off 1) X 100 From the above test results, the toner of the present invention is excellent in both hot offset property and spent property. I understand that.

Example 2 A toner with an average particle size of 10 μm was prepared using the following recipe.

Styrene-n-butyl methacrylate copolymer 92 parts Metal road salt type dye 1 part Carbon black #600 (Mitsubishi Kasei) 7 parts 3.0, average particle size 0.5 μm) was added to 100 parts of the above toner in an amount of 4 parts and mixed in a Henschel mixer to obtain toners 1 to 1 of the present invention.

For comparison, the toner with the above formulation (1) polypropylene-free toner (2) normal polypropylene (molecular ff 112,000
, M1+IIi O1 additionffl'18fs) was kneaded during kneading (3) normal polypropylene fine powder (
An additive toner (molecules m12,000, acid value O1, average particle size 0.5μ, addition amount 4 parts) was prepared.

The following measurements were performed using the above four types of toner.

As described above, it can be seen that the toner of the present invention has excellent hot offset properties and spent properties.

Example 3 A toner having an average particle size of 7.0 μm was prepared using the following recipe.

90 parts of unsaturated polyester 10 parts of carbon black #40 (Mitsubishi Kasei) Next, fine powder of polypropylene whose terminals were modified with carboxylic acid (number average molecular weight: 5300
．． The above toner 100 (acid value 5.2, average particle size 0.3μ)
0.5 parts to 1.0 parts of the mixture was added and mixed in a Henschel mixer to obtain the toner of the present invention. Also, for comparison, (1) a toner with no addition of polypropylene (2) a toner in which ordinary polypropylene (molecular 15300, M value O1 addition amount: 0.5 part) was kneaded during kneading (3) ordinary polypropylene of the toner with the above formulation for comparison. Fine powder (molecule fi5300, acid f+
IIi O1 average particle size 0.3μ, addition amount 0.5 parts) Additive toner was prepared.

The following measurements were performed using the above four types of toner.

As described above, it can be seen that the toner of the present invention has excellent hot offset properties and spent properties.

[Effects] The toner of the present invention prevents hollow 1 to offset, prevents spent, without impairing various properties such as fluidity.
A dry heat fixing toner with improved durability is produced.

Claims (2)

[Claims] (1) A toner for dry heat fixing, characterized in that fine polypropylene powder modified with carboxylic acid at the end is added to a toner containing a binder resin and a colorant. (2) The acid value of the polypropylene fine powder is 0.1 to 50 (K
The toner for dry heat fixing according to claim (1), which has a number average molecular weight of 500 to 20,000 in terms of OHmg/g).