JP2704405B2 - Dry toner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developing toner used for development in electrophotography, electrostatic recording, and the like, and more particularly, to a dry toner for fixing a hot roll. . [Prior art] In electrophotography, an electrostatic latent image formed on a photoreceptor is usually developed with a resin powder containing a pigment, and the obtained visible image is transferred onto transfer paper, and heat, pressure and a combination thereof are used. For example, it is required to perform this fixing step at high speed and with high efficiency, and in view of these points, the hot roll fixing method is often used. In the hot roll fixing method, it is effective to lower the softening point of the binder material of the toner and lower the melt viscosity in order to perform high-speed fixing with low power consumption. With the binder polymer (binder resin) used as a binder, lowering the softening point tends to cause a decrease in fluidity due to caking during toner storage, and lowering the melt viscosity tends to cause image stains due to the offset phenomenon. Become. For this reason, a device for supplying a release agent such as silicone oil to the heat roll is provided to prevent offset, increase the glass transition point of the main binder polymer, or apply inorganic ultrafine powder such as silica to the toner surface. Conventionally, there has been proposed a method for preventing caking at the time of storage by using it as an external additive to a product. [Problems to be solved by the invention] However, in order to supply silicone oil to the hot roll,
Since a supply mechanism is required, the cost of the apparatus is inevitably increased, and maintenance of oil supply is also required. When the glass transition point of the main binder polymer is set high, the softening temperature becomes high, so that low-temperature fixing tends to be difficult. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dry toner capable of performing high-speed and efficient fixing. It is still another object of the present invention to provide a dry toner that hardly causes caking during storage. [Means and Actions for Solving the Problems] It is an object of the present invention to provide a polymer containing an atomic group of-(NHCO)-and having a number average molecular weight of 1,000 or less in a binder. To 100% by weight, and can be achieved by a dry toner for fixing with a hot roll. Conventionally, a high molecular weight resin is used as a binder material of the toner, and a pigment such as a carbon black and a charge control agent are mixed into the resin by a kneading method or the like, and finely pulverized into a toner. In this case, the binder resin holds and fixes the element materials such as pigments, and at the time of fixing, imparts a function of softening the toner by heat and pressure or a combination thereof and attaching the toner along irregularities on the paper surface. The lower the melt viscosity after softening the toner, the lower the temperature at which the toner can be fixed.However, in the case of ordinary polymer materials, the melt viscosity depends on the molecular weight. The strength and also the caking resistance during storage are likely to deteriorate. However, when a polymer having a polar group having a large cohesive energy such as an atomic group called NHCO is used as a binder, the lower limit of the molecular weight that functions as a toner binder is lower than that of a conventional polymer material. When a high molecular weight material having a low molecular weight region having a number average molecular weight of 1000 or less is used, the melt viscosity becomes extremely low and low-temperature fixing becomes possible. Substances having such an NHCO group and having a solid state at room temperature while having a low molecular weight include amide bonds, urethane bonds, urea bonds, thiourethane bonds, carbamic acid carboxylic anhydrides and the like in the molecule. Some have atomic groups, for example, the following atomic groups. NHCO, NHCOO-, NHCONH-, NHCOS-, NHCOOO-, NHCOON, NHCONHNHCONH, NHCONHCO, NHCOCHCOOR ') 2, NHCONHSO 2 R, NHCOCHCOCH 2 COOR', NHCONHR-SO 3 Na, NHCOSO 3 Na, NHCOCl. Wherein R and R ′ are an alkyl group or an aryl group. Further, in the dry toner of the present invention, a binder resin used in a conventional toner can be used in combination as a secondary binder resin. As the secondary binder resin, for example, styrene, styrenes such as parachlorostyrene, vinyl naphthalene, for example, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate,
Vinyl esters such as vinyl propionate, vinyl benzoate and vinyl butyrate, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate Methylene fatty acid carboxylic esters such as phenyl acrylate, α-methyl methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, for example, vinyl methyl ether, vinyl isobutyl ether, vinyl Vinyl ethers such as ethyl ether, for example, vinyl ketones such as vinyl methyl ketone and vinyl xyl ketone, for example, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole , Homopolymers and copolymers of vinyl monomers such as N-vinyl compounds such as N-vinylpyrrolidone and / or various polyester resins, and also carnauba waxes, montan waxes, paraffin waxes, montanic acid ester waxes It can be used in combination with various waxes such as tucks. The usage ratio of the compound having an NHCO atomic group as the main binder and the sub-binder is 5 to 100% by weight (0 to 95% by weight of the sub-binder) for the former. In the dry toner of the present invention, in addition to the above-mentioned binder, a release agent such as polyethylene wax and polypropylene wax can be used in combination, and as a coloring agent, other than ordinary carbon black, other types of pigments, A magnetic substance can be added. EXAMPLES Example 1 An excess of adipic acid was added to nonamethylene bisethylene urethane in anisole, heated to reflux at 60 ° C., cooled, and a polymer was obtained. When the molecular weight was measured by the osmotic pressure method, the number average molecular weight was 950 (this is referred to as Binder A). Further, a polymer obtained by polymerization under the same conditions with a slightly reduced amount of adipic acid had a number average molecular weight of 1200 (this is referred to as a binder B). 10% by weight of carbon black (BPL manufactured by Cabot Corporation) based on binders A and B. 15% by weight of polypropylene wax (660P manufactured by Sanyo Kasei Co., Ltd.) was added to each, kneaded and pulverized to obtain a toner having a particle size of about 10 μm (each of toner A
And B. ). These toners were mixed with a fluorine-based resin-coated carrier, and a fixing test was performed using a modified FX3500 (manufactured by Fuji Xerox Co., Ltd.). When the degree of fixation of the A and B toners at 140 ° C. was compared by rubbing with waste cloth, the toner A was much less blurred than the toner B. Example 2 In methylene chloride, hexamethylene diisodianate was added to butanediol so as to have a small amount of -NCO mole, and the mixture was heated under reflux with stirring to complete the reaction. After cooling, the precipitated polyurethane resin is over-separated,
It was dissolved in DMF and thrown into methanol for reprecipitation purification (this is referred to as binder C). The polyurethane resin residue was separated from the cooled mother liquor after the reaction by reprecipitation purification using methanol (this is referred to as binder D). The molecular weight determined by the vapor osmotic pressure method was 1760 for C and 900 for D. Binder C, D, carbon black (BPL made by Cabot Corporation) 10% by weight, polypropylene wax (660P made by Sanyo Chemical Co., Ltd.) 15% by weight was mixed, kneaded and pulverized, toner of about 12μm particle size (Toners C and D, respectively). When a fixing test was performed on these toners in the same manner as in Example 1, the fixing degree at 150 ° C. was remarkably superior to that of the D toner. [Effects of the Invention] The dry toner for fixing a hot roll of the present invention is-(NHCO)-
A low-molecular-weight polymer material (number-average molecular weight of 1000 or less) having high hardness at room temperature having an atomic group of 5 to 5 in a binder resin
It contains 100% by weight and has the characteristics that fixing can be carried out efficiently at high speed and that caking hardly occurs during storage.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Masayuki Takeda               1600 Takematsu, Minamiashigara Fuji Xerox               Takematsu Office Co., Ltd. (72) Inventor Chiaki Suzuki               1600 Takematsu, Minamiashigara Fuji Xerox               Takematsu Office Co., Ltd. (72) Inventor Ikutaro Nagatsuka               1600 Takematsu, Minamiashigara Fuji Xerox               Takematsu Office Co., Ltd.                (56) References JP-A-63-58354 (JP, A)                 JP-A-63-66564 (JP, A)                 JP-A-51-118436 (JP, A)                 JP-A-55-6343 (JP, A)                 JP-A-56-6243 (JP, A)                 JP-A-57-198466 (JP, A)                 JP-A-58-85442 (JP, A)                 JP-A-58-86557 (JP, A)                 JP-A-58-95750 (JP, A)                 JP-A-60-21054 (JP, A)                 JP-A-60-168701 (JP, A)                 JP-A-61-172154 (JP, A)

Claims (1)

(57) [Claims] A polymer material containing an atomic group of-(NHCO)-in the molecule and having a number average molecular weight of 1,000 or less in the binder is 5 to 10%.
A dry toner for fixing with a hot roll, comprising 0% by weight.