JPH05249728A - Developer for electrostatic image development - Google Patents

Abstract

(57) [Summary] [Structure] Resin 100 in toner used for start developer
A toner for developing an electrostatic charge image, wherein the content of polyalkylene is more than 100 parts by weight of the resin in the replenishing toner. [Effects] Especially, the occurrence of initial fog and the change of copy image are stable with a small number of continuous copies, and the copy image, image density, fog, etc. are consistently good from beginning to end, and the heating roller is less contaminated. Image formation showing sufficient fixing property is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for developing an electrostatic charge image used for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method or the like.

[0002]

2. Description of the Related Art In a developing process, a developer used in an electronic copying machine or the like is once attached to an image carrier such as a photoconductor on which an electrostatic charge image is formed, and then a photoconductor is used in a transferring process. After being transferred from the sheet to the transfer sheet, it is fixed on the copy sheet surface in the fixing step. At that time, as a developer for developing the electrostatic charge image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer not requiring a carrier (magnetic toner, non-toner). Magnetic toner) is known.

Toners contained in the developer include positively chargeable toners and negatively chargeable toners. Conventionally, as those imparting chargeability to positively chargeable toners, nigrosine dyes, quaternary ammonium salts have been used. For example, a charge control agent as an additive to a toner or a coating agent that imparts a predetermined chargeability to a carrier is known, while a charge control agent such as a metal-containing azo dye is used to impart a negative chargeability. Inorganic oxides such as finely divided silica and carrier coating agents are known.

[0004]

In the past, it has been known that a toner contains a polyalkylene such as low molecular weight polypropylene in order to prevent an offset phenomenon during fixing. (Japanese Patent Publication No. 52-3304
However, the conventional toner containing polyalkylene as a release agent is not preferable in terms of image quality stability when continuously copied and printed for a long time, and durability of the developer. I was not always completely satisfied.

That is, for example, when copying with a two-component developer composed of a toner and a carrier, a toner using a polyalkylene having a too low molecular weight has an excellent effect of preventing an offset phenomenon in fixing, but the toner The deterioration of the fluidity of the ink causes the streak to be noticeable on the black solid part and the black or white parts to be noticeably chipped at the leading edge or the trailing edge, resulting in poor copy image quality. Copying defects are likely to occur due to the filming phenomenon that adheres to the photoconductor, and the toner unevenly rising property is deteriorated due to the accumulation of wax ubiquitous toner in the developer, which makes image changes large and unstable. However, there was a problem in that the image quality deteriorates and defects occur during continuous copying.

Further, a toner using polyalkylene having an excessively high molecular weight cannot obtain a sufficient effect for preventing an offset phenomenon in fixing. Therefore, if the amount of polyalkylene added is excessively increased, the same problem as described above occurs. there were. As a method of partially solving such a problem, Japanese Patent Publication No. 58-586.
No. 64, Japanese Patent Publication No. 57-52574, Japanese Patent Publication No. 2
It is proposed to use a specific polyalkylene in combination with a specific resin and other requirements in Japanese Patent Application Laid-Open No.-6055, Japanese Patent Publication No. 38945/1990.

However, even with such a method, the toner characteristics are not sufficient, and there are the following problems. That is, in general, when using a copying machine, etc., when the start developer is set in the copying machine and the number of copies is continuously piled up, the toner being developed is consumed, and the amount of consumed toner is equal. In this case, the replenishment toner is supplied in accordance with the above, but at this time, the change of the copy image is likely to be large, and especially the fog which is the stain on the white background portion is high in the initial period, and the change is also likely to be large. There was a problem. As a result of earnest studies to solve the above problems, the inventors of the present invention usually differed in the amount of alkylene in the toner for start phenomenon agent and the toner for replenishment, which use exactly the same composition in consideration of productivity and the like. The inventors have found that a phenomenon agent which suppresses the initial fog at a low level and has a small change in the copy image can be obtained, and has reached the present invention. That is, the object of the present invention is to develop an electrostatic charge image which is stable particularly with little occurrence of initial fog and copy image change during continuous copying of a large number of sheets, excellent image quality, little change in image quality over time, and excellent charging characteristics. To provide a developer for use. Another object of the present invention is to provide a developer for electrostatic charge image development, which has high image density, good stability, little toner scattering, little image stain such as fog, and excellent life stability. is there.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is, therefore, that the polyalkylene content (Ws) in the toner used as the starting developer is higher than the polyalkylene content (Wf) in the replenishing toner. It is easily achieved by a developer for electrostatic charge development characterized in that Furthermore, the polyalkylene content in the toner described above preferably satisfies the following relationship, and is easily achieved by the developer for developing an electrostatic charge image.

## EQU00004 ## Ws-Wf.gtoreq.0.2 parts by weight, 1.ltoreq.Ws.ltoreq.10 parts by weight, 0.8.ltoreq.Wf.ltoreq.9.8 parts by weight As the resin component usable in the present invention, a toner for developing an electrostatic charge image is used. Various known materials suitable for the above can be used. For example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer. , Styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-acrylic acid Phenyl copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, and styrene-phenyl methacrylate copolymer) Union), styrene-α-black Styrene resins such as methyl acrylate copolymers and styrene-acrylonitrile-acrylic acid ester copolymers (styrene or homopolymers containing styrene substitutes), vinyl chloride resins, rosin-modified maleic acid resins, phenols Resin, epoxy resin, polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, polycarbonate resin, etc. Particularly preferred resins and the like for use in the invention include styrene resins, saturated or unsaturated polyester resins and epoxy resins.

The above-mentioned resins are not limited to being used alone, but may be used in combination of two or more kinds. Further, if necessary, a resin having a molecular weight design having one or two or more peaks of molecular weight, a crosslinking agent, etc. Can also be used as a crosslinked resin. The colorant used in the present invention is not particularly limited as long as it is conventionally used, and any appropriate pigment or dye can be used. For example, titanium oxide, zinc white, alumina white, calcium carbonate, navy blue, carbon black, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dyes and pigments, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl methane dyes. , Anthraquinone dye, monoazo and disazo dyes and pigments are used alone or in combination with a colorant corresponding to the color of the toner. The content of the colorant may be an amount sufficient to color the toner so that a visible image can be formed by development, and for example, 1 to 20 parts by weight with respect to 100 parts by weight of the resin.
It is preferable to use parts by weight.

Examples of the polyalkylene used in the present invention include polypropylene, polyethylene, polybutene, polyhexene, ethylene-propylene copolymer, ethylene-
Butene copolymers and the like are listed, but polypropylene and polyethylene are particularly effective. The following are typical examples of commercially available polyalkylenes. □ Sanyo Chemical Industry Co., Ltd .: Sun wax series (131
-P, 151-P, 161-P, 165-P, E-25
0P, LEL-250P, LEL-400P, LEL-
800P, etc.), Viscol series (330-P, 55
0-P, 660-P, TS-200, etc.) and the like. □ Hoechst Japan KK: Hoechst wax series (PE520, PE130, PE190, PP230,
PP690 etc.) etc. □ Mitsui Petrochemical Industry Co., Ltd .: PP wax series (N
P055, NP105, NP805, NP505, etc.),
High wax series (RX210S, RX310S,
410P, 420P, 320P, 210P, 4400
G, etc.) etc. □ Eastman Chemical Japan Co., Ltd .: Epollen series (N10, N11, N14, N15, N20, N2
1, E10, E14, E15, E43, C10, C1
3, C15, C17, etc.) etc.

Weight average molecular weight (Mw) of polyalkylene
Is preferably 1,000 to 40,000, more preferably 2000 to 30000 in weight average molecular weight (Mw), and approximately 2 to 4 in weight average molecular weight (Mw) / number average molecular weight (Mn). If the weight average molecular weight is less than 1,000, the effect of preventing offset of fixing is obtained, but the image quality such as the streak in the black solid portion of the toner and the lack of image is poor, and a high image density cannot be stably obtained, and This is not preferable because filming occurs easily. Weight average molecular weight is 400
When it is higher than 00, the image quality and the image stability are excellent, but the offset prevention effect in fixing is not sufficiently obtained, which is not preferable. The molecular weight and the molecular weight distribution are measured by a high temperature gel permeation chromatography method (hereinafter referred to as GPC), which may be slightly different depending on the measurement conditions, but can be measured, for example, under the following conditions. That is, O-dichlorobenzene (added with 0.1% ionol) was used as a solvent at a temperature of 1350 ° C., and 1 m / min was used.
at a flow rate of 1 l and a sample solution having a concentration of 0.1% by weight is added to 400
Inject μl and measure. Further, in measuring the molecular weight of the sample, a polystyrene-converted value is used from a calibration curve prepared using a monodisperse polystyrene standard sample. The column to be used is not limited,
For example, there is A-80M manufactured by Showdex.

The melting point of the polyalkylene is preferably 100 to 180 ° C., more preferably 120 to 160 ° C., determined from the peak position temperature of the endothermic pattern of thermal analysis (differential thermal analyzer, differential scanning calorimeter, etc.). .. If the toner has a high melting point of 180 ° C. or higher, the polyalkylene is not sufficiently melted even when heated when the toner is manufactured by a kneading machine and the like, the compatibility and dispersibility in the resin are deteriorated, and the minimum fixing of the toner The temperature deteriorates, which is not preferable. If the toner has a low melting point of 100 ° C. or less, it is not preferable because the shear of kneading is less likely to occur when the toner is manufactured by a kneader and the dispersibility of the colorant and other internal additives is deteriorated. The polyalkylene content in the toner varies depending on the resin component used, the colorant, the fixing mechanism, etc., but in the heating roller fixing method, the resin content is generally 100%.
0.5 to 20 parts by weight is preferable with respect to parts by weight, and further 0.
Amounts of about 8 to 10 parts by weight are preferable, and if less than 0.5 parts by weight, the effect of preventing offset in fixing becomes small, and 2
If it exceeds 0 parts by weight, the fluidity and charging property of the toner are adversely affected, resulting in poor image quality and poor image stability, which is not preferable.

In the present invention, the polyalkylene content represents the amount of polyalkylene used in parts by weight relative to 100 parts by weight of the resin used in the toner, and is supplemented with the polyalkylylene content (Ws) in the toner for the starting developer. Of polyalkylene content (Wf) in toner for toner is Ws> Wf
It is an essential condition that the relationship of
s-Wf ≧ 0.2 parts by weight, 1 ≦ Ws ≦ 10 parts by weight, 0.
It is preferable that the relationship of 8 ≦ Wf ≦ 9.8 is satisfied.
Other than the above relational expressions, the fog level is particularly high at the initial stage of continuous copying or the like, which is not preferable. Two or more kinds of polyalkylene in the toner may be used in combination, and in that case, the total weight of the polyalkylene may satisfy the above relationship. In addition to the above-mentioned polyalkylene, a small amount of paraffin wax, higher fatty acid, fatty acid amide, metal soap, etc. may be added. In addition, in order to adjust the chargeability of the toner, in the case of a positively chargeable toner, a known charge control agent such as a nigrosine dye, a quaternary ammonium salt, a triaminotriphenylmethane compound, an imidazole compound, a negative charge In the case of a hydrophilic toner, a known charge control agent such as a metal-containing azo dye, a metal salicylate compound and a metal alkylsalicylate compound may be added in an appropriate amount. The addition amount is preferably about 0.05 to 10 parts by weight with respect to 100 parts by weight of the resin.

The present invention effectively works when a positively chargeable charge control agent is used, and further, JP-B-1-54694,
It works more effectively when using the quaternary ammonium salt-based charge control agent described in JP-B-1-54695, JP-B-1-54696 and the like. Further, on the surface of the toner particles, for the purpose of improving the fluidity of the toner, the aggregation resistance, adjusting the toner resistance, and controlling the charging property, titania, silica, alumina, inductive titania-antimony-tin compound, magnetite, ferrite, hydrothalisite. It is also possible to add metal oxide fine powders such as the above and organic fine powders such as an acrylic resin, individually or as a mixture. Toner particles 1
About 0.01 to 5 parts by weight is preferable with respect to 00 parts by weight. When the toner of the present invention is used in a two-component developer, it may be used as a mixture with a magnetic carrier, and the content ratio of carrier to toner in the developer is preferably 100: 1 to 10 parts by weight. The magnetic carrier has a particle size of 20 to 2
Iron powder, ferrite powder, magnetite powder of about 00 μm,
A conventionally known carrier such as a magnetic resin carrier can be used. Further, those whose surface is coated with a known silicone resin, acrylic resin, fluorine resin, or a mixture of these resins can be preferably used.

The present invention works effectively when a developer obtained by mixing a positively charged toner and a carrier coated with a fluororesin or a silicone resin is used, and the positively charged toner and the silicone resin are mainly coated. It works more effectively when a developer mixed with a carrier is used. The toner of the present invention is a magnetic one-component toner containing magnetism such as magnetite, which is a one-component developer that does not use a carrier,
Alternatively, it can be used as a non-magnetic one-component toner containing no magnetic substance. As the method for producing toner particles, various conventional toner production methods can be applied,
For example, as a general example, first, a resin, a colorant, a wax, a charge control agent, etc. are uniformly dispersed and mixed by a known mixer,
Next, the mixture may be melt-kneaded with a closed kneader or a single-screw or twin-screw extruder, cooled, pulverized, and classified. In recent years, a single-screw or twin-screw extruder is mainly used because of its superiority such as continuous production of kneaders. For example, KTK twin-screw extruder manufactured by Kobe Steel, TEM extruder manufactured by Toshiba Machine Co., Ltd.,
KCK twin screw extruder, Ikegai Ironworks PC
An M-type twin-screw extruder, a bus kneader manufactured by Bus Co., and the like are preferable. In addition,
To obtain toners having different polyalkylene contents, two types of toners having different compositions may be manufactured. The average particle diameter of the toner is preferably 3 to 20 μm. Further, when the toner is externally added, the classified toner and the external additive may be mixed by stirring with a high-speed stirrer or the like, and if necessary, the type of the external additive used for the start developer toner and the replenishment toner, The addition amount may be different. The start developer can be prepared by mixing and stirring the toner and carrier obtained in the above steps with a ball mill, a V-type mixer or the like for a predetermined time.

[0016]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, simply "parts" means "parts by weight".

<Example 1>

[Table 1] Replenishment for start -Styrene / n-butyl acrylate copolymer resin 100 parts 100 parts (flow softening point 130 ° C, glass transition point 62 ° C) -Colorant carbon black □ MA-7 5 parts 5 parts (Mitsubishi Kasei Co., Ltd.)-Polyalkylene low molecular weight polypropylene 4 parts 3 parts (Mw = 14000) -Charge control agent Bontron P51 2 parts 2 parts (Orient Chemical Co. quaternary ammonium salt) Start toner and replenishment toner are each the above composition. Was mixed with a continuous twin-screw extruder, pulverized, and classified to obtain a black toner having an average particle size of 10 μm. To 100 parts of this black toner, 0.2 part of silica powder (R972 manufactured by Nippon Aerosil Co., Ltd.) was externally added by a Henschel mixer to obtain a toner A for start and a toner B for replenishment. 4 parts of the obtained toner A and 100 parts of a ferrite powder carrier having an average particle size of 100 μm and surface-coated with a methylsilicone-containing resin were mixed and stirred to prepare a starting developer A.

Next, with respect to this developer A, an organic photoconductor is used as a photoconductor, and a fixing device is composed of silicon rubber coated with a thin layer of Teflon resin, and a heater lamp is mounted inside the roller. It is a fixing machine composed of a lower pressure roller, and the fixing temperature is set to 190 ° C without supplying a releasing liquid such as silicone oil.
Using a copier with a copy speed of 50 sheets / min, a temperature of 23-2
100,000 under the condition of 5 ° C. and humidity of 50 to 60% RH
0 live-action test was performed. The replenishment toner used in the actual shooting test is the toner B described above. As a result of the live-copy test, from the initial stage to 100,000 copies, the uniformity of the black portion of the copy was good, the chipping was good, the image density was high and stable, and there was no increase in the fog that is the stain on the white background portion of the copy. The toner and the developer were excellent in durability performance with almost no contamination due to toner scattering. Further, the fixing roller was hardly stained, and neither the front side nor the back side of the fed paper was stained at all.

<Example 2>

[Table 2] Replenishment for start -Styrene / n-butyl acrylate copolymer resin 100 parts 100 parts (flow softening point 130 ° C, glass transition point 62 ° C) -Colorant carbon black MA-7 5 parts 5 parts (Mitsubishi Kasei)・ Polyalkylene Low molecular weight polypropylene 3 parts 3 parts (Mw = 14000) ・ Polyalkylene low molecular weight polypropylene 1 part None (Mw = 8500) ・ Charge control agent Bontron P51 2 parts 2 parts (Orient Chemical Co. quaternary ammonium) Salt) Starting toner C is the same as in Example 1 except that the starting toner and the replenishing toner are mixed in the above composition.
A starting developer C and a replenishment toner D were prepared by using, and 100,000 actual copying tests were carried out. As a result of the actual copying test, even from the initial stage to 100,000 copies, the uniformity of the black portion of the copy was good, the chipping was good, the image density was high and stable, and there was no increase in the fog that was a stain on the white portion of the copy. The toner and the developer were excellent in durability performance with almost no contamination due to toner scattering.
Further, the fixing roller was hardly soiled, and the passed paper was not soiled at all on the front and back sides.

<Example 3>

[Table 3] Replenishment for start -Styrene / n-butyl acrylate copolymer resin 100 parts 100 parts (flow softening point 130 ° C, glass transition point 62 ° C) -Colorant carbon black MA-7 5 parts 5 parts (Mitsubishi Kasei)・ Polyalkylene low molecular weight polypropylene 2 parts 2 parts (Mw = 14000) ・ Polyalkylene low molecular weight polyethylene 2 parts 1 part (Mw = 4000) ・ Charge control agent Bontron P51 2 parts 2 parts (Orient Chemical Co., Ltd. grade 4) Ammonium salt) Starting toner E was prepared in the same manner as in Example 1 except that the starting toner and the replenishing toner were mixed in the above composition.
A starting developer E and a replenishment toner F were prepared using the above, and an actual copying test was conducted on 100,000 sheets. As a result of the actual copying test, even from the initial stage to 100,000 copies, the uniformity of the black portion of the copy was good, the chipping was good, the image density was high and stable, and there was no increase in the fog that was a stain on the white portion of the copy. The toner and the developer were excellent in durability performance with almost no contamination due to toner scattering.
Further, the fixing roller was hardly soiled, and the passed paper was not soiled at all on the front and back sides.

Comparative Example 1 Using the toner B of Example 1 and the starting developer G prepared in the same manner as in Example 1 and the replenishment toner B of Example 1 in the same manner as 100,000.
A live-action photo test was performed. As a result of the live-copy test, even from the initial stage to 100,000 copies, the uniformity of the black portion and the chipping were good, and the image density was almost stable.
The fog up to about 0 sheets was high, and the fog decreased after 5000 sheets, which was not preferable. It should be noted that the fixing roller was scarcely soiled, and neither the front side nor the backside of the fed paper was soiled at all.

Comparative Example 2 Using the toner F of Example 3, the starting developer H prepared in the same manner as in Example 3 and the replenishment toner F of Example 3 were similarly used to obtain 100,000.
A live-action photo test was performed. As a result of the live-copy test, even from the initial stage to 100,000 copies, the uniformity of the black portion and the defect were good, and the image density was almost stable.
Fog up to about 0 sheets was slightly high, and fog decreased after 2000 sheets, which was not preferable. It should be noted that the fixing roller was scarcely soiled, and neither the front side nor the backside of the fed paper was soiled at all.

[0023]

EFFECT OF THE INVENTION By using the developer for developing electrostatic image of the present invention, the occurrence of fog at the beginning and the change of copy image are small and stable even when copying a large number of sheets in succession, and the copy is consistent from beginning to end. An image is formed with good image quality, image density, fog, etc., and with less stain on the heating roller, and with sufficient fixing performance, which provides a great industrial advantage.

Claims (4)

[Claims] 1. A polyalkylene content (W _S parts by weight) relative to 100 parts by weight of a resin in a toner used as a start developer, and a polyalkylene content (W _f parts by weight) relative to 100 parts by weight of a resin in a replenishing toner. A developer for developing an electrostatic charge image, which is characterized by being more than 2. The electrostatic charge image developing developer according to claim 1, wherein the polyalkylene content in each toner according to claim 1 satisfies the relationship of the following formula (I). [Equation 1] W _S −W _f ≧ 0.2 parts by weight (I) 3. The polyalkylene content in the toner used in the start developer according to claim 1, is represented by the following formula (I
The developer for developing an electrostatic charge image according to claim 1, wherein the relationship of I) is satisfied. [Equation 2] 1 ≦ W _f ≦ 10 parts by weight (II) 4. The developer for developing an electrostatic charge image according to claim 1, wherein the content of polyalkylene in the replenishing toner according to claim 1 satisfies the relationship of the following formula (III). [Equation 3] 0.8 ≦ W _S ≦ 9.8 parts by weight (III)