JPH11258859A - Developing method using dry non-magnetic one-component toner - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve toner fixability and durability and to charge toner satisfactorily, thereby preventing poor charging and fogging before they occur. To provide a developing method using a dry non-magnetic one-component toner. A developing sleeve (5) and a developing sleeve (5) are provided.
A dry non-magnetic one-component toner in which a layer of a dry non-magnetic one-component toner is formed on a developing sleeve 5 by a blade 4 opposed to the toner. The main component is a polyester resin in which a high molecular weight is formed, and one of the developing sleeve 5 and the blade 4 is made of metal and the other is a synthetic resin or natural rubber or a mixture thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method using a dry non-magnetic one-component toner (hereinafter simply referred to as "toner"), and more particularly, to improving the durability of the toner and improving the charging of the toner. The present invention relates to a technique for preventing fusion of toner and generation of fogging between a developing sleeve and a blade disposed opposite to the developing sleeve.

[0002]

2. Description of the Related Art A non-magnetic one-component toner is required to have a fixing property (fixing strength) that can be relatively easily melted and a durability that is thermally stable and withstands a mechanical load. Conventionally, non-magnetic one-component toners have been manufactured by mixing a colorant such as wax, carbon black and a charge control agent with a polyester resin using, for example, trimellitic acid as a crosslinking agent. However, such a toner has a problem that it is difficult to achieve both the above-described fixing property and durability. In order to satisfy such a demand, a toner using a polyester resin having a high molecular weight formed by urethane extension has been developed (for example, JP-A-63-56659).

[0003]

However, in the case of the toner using the polyester resin as described above, when both the developing sleeve and the blade are made of synthetic rubber, in particular, when one of them is formed of urethane rubber, the toner is not applied to the toner. It was found that poor charging occurred and the toner layer was not formed uniformly on the developing sleeve. Therefore, according to the present invention, not only can the toner fixability and durability be improved,
It is an object of the present invention to provide a developing method using a dry non-magnetic one-component toner capable of favorably charging a toner.

[0004]

The inventors of the present invention have conducted studies using a toner containing a polyester resin having a high molecular weight formed by urethane extension as a main binder component, and using various materials for a developing sleeve and a blade. It has been found that when one of them is a metal and the other is a synthetic resin, charging failure does not occur. It has also been found that poor charging does not occur when natural rubber or a mixture of natural rubber and synthetic resin is used in place of synthetic resin. In addition, since the polyester resin which formed a high molecular weight body by urethane extension is stronger than other polyester resins,
It was found that it is difficult for the external additive such as silica fine particles to be buried in a large number of copies, and as a result, it is difficult for the charging performance to decrease due to the decrease in fluidity.

[0005] The present invention has been made based on the above-mentioned findings, and a dry non-magnetic one-component toner in which a layer of dry non-magnetic one-component toner is formed on the developing sleeve by a developing sleeve and a blade facing the developing sleeve. In the developing method using the component toner, the dry non-magnetic one-component toner has, as a main binder component, a polyester resin having a high molecular weight formed by urethane extension, and one of a developing sleeve and a blade is made of metal and the other is made of metal. It is a synthetic resin or a natural rubber or a mixture thereof. Hereinafter, more preferred embodiments of the present invention will be described.

[0006]

DETAILED DESCRIPTION OF THE INVENTION A. Developing Device FIG. 1 is a side sectional view showing an example of a developing device for carrying out the present invention. In the figure, reference numeral 1 denotes a cylindrical photosensitive drum as an electrostatic latent image holding member, 2 denotes a hopper, 3 denotes toner,
Reference numeral 4 denotes a blade for regulating the layer thickness of the toner, 5 denotes a developing sleeve, 6 denotes a toner supply roll, and 7 denotes a stirrer. An electrostatic latent image is formed on the surface of the photosensitive drum 1 by a known electrophotographic method. The toner 3 is contained in the hopper 2, and the toner 3 is carried on the surface of the developing sleeve 5 by the blade 4 in a state where the layer thickness is regulated.
Urethane rubber is preferably used for the surface layer of the developing sleeve 5, but may be made of silicone rubber, other synthetic resin, natural rubber, or a mixture of synthetic resin and natural rubber.

A nonmagnetic austenitic stainless steel is preferably used for the blade 4, but other ferrous metals or nonferrous metals can be used. The blade 4 can be made of a magnetic metal.

In this embodiment, the developing sleeve 5 is in contact with the photosensitive drum 1, but the present invention is also applicable to a system in which the toner flies to the photosensitive drum 1 without contact. The developing sleeve 5 can be configured to apply a DC or AC voltage. Developing sleeve 5
Is carried by the rotation of the developing sleeve 5 and comes into contact with the photosensitive drum 1 having an electrostatic latent image to visualize the electrostatic latent image. The developing sleeve 5
Is made of metal such as stainless steel, the blade 4 is made of synthetic resin such as urethane rubber, natural rubber, or a mixture thereof.

B. Toner The urethane-extended polyester resin (hereinafter referred to as urethane-extended polyester resin) used in the toner of the present invention is a urethane-extended polyester resin obtained by crosslinking a base polyester resin with a diisocyanate and urethane-extending the urethane. , And then obtained by mixing with another polyester resin.

The base polyester resin is obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol. Examples of the polycarboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, aliphatic dibasic acids such as hexahydrophthalic anhydride, maleic acid,
Aliphatic unsaturated dibasic acids such as maleic anhydride, fumaric acid, itaconic acid and citraconic acid; aromatic dibasic acids such as phthalic anhydride, phthalic acid, terephthalic acid and isophthalic acid; and lower alkyl esters thereof are used. .

The polyhydric alcohols include, for example, ethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, A diol such as bisphenol A propylene oxide adduct and a triol such as glycerin, trimethylolpropane, and trimethylolethane are used.

As the polycondensation method, there are known high-temperature polycondensation,
Solution polycondensation and the like are used. The usage ratio of the polyhydric carboxylic acid and the polyhydric alcohol is generally 0.8 to 1.4, which is the ratio of the former carboxyl group to the latter hydroxyl group.
The number average molecular weight of the base polyester resin is 100
It is from 0 to 30,000, preferably from 2000 to 15,000. If the number average molecular weight is less than 1,000, the offset resistance of the toner may decrease, which is not preferable. 30,000
If the ratio exceeds the above, the viscosity of the reaction between the base polyester resin and the diisocyanate is remarkably increased, which is not preferable from the viewpoint of production, and the fixability of the toner may be lowered.

As the diisocyanate, for example, methylene diisocyanate, hexamethylene diisocyanate, isophone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate and the like are used. The use range of the diisocyanate is 0.3 to 0.9 per mole of the base polyester resin.
5 mol, especially 0.5 to 0.8 mol, is preferred. If the amount of diisocyanate is less than 0.3 mol, the offset resistance of the toner may decrease. If the amount exceeds 0.95 mol, the viscosity increases significantly during the reaction, and in some cases, the viscosity of the urethane cross-linked polyesmol resin increases and stirring may occur. This is not preferable in terms of production because it becomes impossible.

The urethane-crosslinked polyester resin as a material of the urethane-extended polyester resin can be obtained, for example, by adding diisocyanate to a base polyester resin and reacting at a temperature of 50 to 150 ° C. for several hours in the presence or absence of a solvent. . The other polyester resin is obtained by the same method as the base polyester resin, and has a number average molecular weight of 1,000 to 10,000, preferably 2,000 to 6,000. Number average molecular weight is 10
If it is less than 00, the offset resistance of the toner may decrease, and if it exceeds 10,000, the fixability may deteriorate. The polyhydric carboxylic acid and polyhydric alcohol used in the production of other polyester resins may be the same as or different from the base polyester resin.

In the urethane-extended polyester resin,
The content ratio of the urethane crosslinked polyester resin to the other polyester resin is preferably from 20:80 to 95: 5 by weight, more preferably from 30:70 to 80:20.
When the content ratio of the urethane crosslinked polyester resin is less than 20% by weight of the total of both, the offset resistance of the toner is reduced, and the content ratio of the other polyester resin is 5% of the total of both.
If the amount is less than about 10% by weight, the pulverizability in the toner production process deteriorates, which is not preferable.

The glass transition temperature of the urethane-extended polyester resin is preferably from 40 to 80 ° C., more preferably 5 to 80 ° C.
0-60 ° C is good. When the glass transition temperature is lower than 40 ° C., the blocking property of the toner may be deteriorated.
When the temperature exceeds ℃, the fixing property may be deteriorated.

The urethane-extended polyester resin is prepared by mixing a urethane-crosslinked polyester resin alone or a solution containing a urethane-crosslinked polyester resin with another polyester resin alone or a solution containing another polyester resin at a predetermined ratio in a container as required. After heating and stirring and mixing, it can be obtained by treating in a high-temperature vacuum in order to remove unnecessary solvents, residual monomers and odor due to thermal degradation.

The toner of the present invention contains a coloring agent, a charge controlling agent, and other components in addition to the urethane-extended polyester resin. Examples of the colorant include a pigment or a dye used in a toner. Pigments such as carbon black, aniline black, acetylene black,
Naphthol yellow, Hansa yellow, Rhodamine lake, Alizarin lake, Bengala, phthalocyanine blue, indanthrene blue and the like are exemplified. These pigments are used in an amount necessary and sufficient to maintain the optical density of the fixed image, and are usually added in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, per 100 parts by weight of the resin. Examples of the dye include an azo dye, an anthraquinone dye, a xanthene dye, and a methine dye. These dyes are usually added in an amount of 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the resin.

Examples of charge controlling agents include quaternary ammonium salts such as nigrosine, tributylbenzine ammonium-1-hydroxy-4-naphthosulfonic acid, tetrabutylammonium tetrafluoroborate, and lake pigments thereof, triphenylmethane dyes and the like. These lake pigments, metal salts of higher fatty acids, diorganotin borates such as dibutyl tin oxide, dioctyl tin oxide, dibutyl tin borate, dioctyl tin borate, dicyclohexyl tin borate, metal-containing complex salts or complex dyes, and functional groups are copolymerized or grafted. Positive or negative chargeable materials such as polymerized so-called resin type band control agents can be used. These can be used alone or in combination of two or more. Other components include low-molecular-weight polypropylene, release agents such as low-molecular-weight polyethylene, ferrite, magnetic agents such as magnetite, alumina,
An abrasive such as titanium oxide is used.

Preferably, silica fine particles are adhered to the toner surface. When silica fine particles are adhered to the toner surface, the silica fine particles are added in an amount of 0.1 part by weight to 100 parts by weight of toner.
It is preferably from 0.5 to 3 parts by weight. Further, it is desirable that the toner is spherical (rounded). In order to make the toner spherical, in the pulverizing step, Kryptron manufactured by Kawasaki Heavy Industries, Ltd. may be used as a pulverizer. Further, mechanical and thermal energy is applied to the classified toner particles by a reforming device using an impact force or a compressive force, for example, a hybridization device manufactured by Nara Machinery Co., Ltd., or an angmill device manufactured by Hosokawa Micron Co., Ltd. To make the toner spherical. The spheroidized toner refers to toner particles having a circularity of 0.96 to 1 in the following toner particles having a circle-equivalent particle diameter of 1.6 μm or more. Toner particles having a circularity of 0.96-1 are:
Compared to toner particles having a particle size of less than 0.96, toner fusion and fogging are less likely to occur. The circle equivalent particle diameter and circularity are
Approximately 3,000 toner particles can be obtained by measuring with a flow particle image analyzer: FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd. In this case, the circle-equivalent particle diameter is the diameter of a circle having the same area as the projected area of the toner particles, and the circularity is calculated by the following equation.

(Equation 1)

[0021]

The present invention will be described in more detail by way of examples. In the following description, “parts” means “parts by weight”. <Example 1> [Production of urethane-extended polyester resin]
Bisphenol A propylene oxide adduct 1700
Parts, diethylene glycol 150 parts, isophthalic acid 86
0 parts were charged, and polycondensation was performed at 240 ° C. while introducing nitrogen into the polymerization vessel to obtain a base polyester resin. Next, when the acid value of the base polyester resin became 5 mgKOH / g or less, the base polyester resin was cooled to 130 ° C., and xylene 2500
Parts and 100 parts of methylene diisocyanate,
The reaction was carried out at 20 ° C. for 4 hours to obtain a urethane crosslinked polyester resin.

On the other hand, bisphenol A
1400 parts of a propylene oxide adduct, 100 parts of diethylene glycol, 800 parts of isophthalic acid, and 50 parts of phthalic anhydride are charged, and 230 parts are introduced while introducing nitrogen into the polymerization vessel.
Polycondensation was performed at ℃ to obtain another polyester resin.

The urethane crosslinked polyester resin and another polyester resin were mixed in a xylene solvent at a ratio of 30:70, and the solvent was removed in a vacuum system to obtain a urethane extended polyester resin. This urethane-extended polyester resin is
Glass transition point 60.8 ° C, melting start temperature 102.0
° C and the flow softening point was 133.0 ° C.

[Production of Toner] The following materials are stirred and mixed by a super mixer, and then melt-kneaded by a twin-screw kneading extruder.
It was pulverized by a jet mill and classified by an air classifier to obtain a toner having an average particle size of 7.5 μm. To 100 parts of this toner, 0.4 part of silica fine particles (trade name: H3004, manufactured by Clariant Japan KK) was added and mixed with a Henschel mixer manufactured by Mitsui Mining Co., Ltd. to obtain a toner of an example. The circularity of this toner was 0.93.

-91 parts of the above-mentioned urethane-extended polyester resin-2 parts of polypropylene wax (trade name: Viscol 550P, manufactured by Sanyo Chemical Co., Ltd.)-5 parts of carbon black (trade name: REGAL400R, manufactured by Cabot Corporation)-Metal-containing complex dye-based electrification Control agent 2 parts (trade name: Bontron S-44, manufactured by Orient Chemical Co., Ltd.)

Next, in FIG. 1, the toner is put into a hopper 2 of a developing device in which the blade 4 is made of stainless steel and the surface layer of the developing sleeve 5 is made of urethane rubber, and a printer Phaser 540 manufactured by Sony Techtronics Co., Ltd.
And an initial image was obtained, and the charge amount was measured.
Thereafter, the developing device was taken out of Phaser 540, set in a forced stirring device, and forcedly stirred for 30 minutes at a peripheral speed of the developing sleeve 5 of 300 rpm. Next, after the developing device was set back on the printer, the image, the charge amount, and the presence or absence of blade fusion were checked, and data after forced stirring was obtained. The results are shown in Table 1. In Table 1, the charge amount is measured by a blow-off powder charge amount measuring device TB-200 manufactured by Toshiba Chemical Co., Ltd., and the charge lost at the time of sucking the toner on the surface of the developing sleeve 5 with a suction device is measured. The image density was measured by measuring a solid image with a reflection densitometer RD-914 manufactured by Macbeth.
It was measured at 1001 DP.

Example 2 The urethane cross-linked polyester resin and another polyester resin were mixed at a ratio of 40:60 in a xylene solvent, the glass transition point was 63.2 ° C., the melting onset temperature was 109.0 ° C., and the flow was softened. Point 139.0 ° C
The same toner as in Example 1 was produced except that the urethane-extended polyester resin was used. Further, development was continuously performed using this toner under the same conditions as in Example 1, and the results are also shown in Table 1. The circularity of this toner was 0.92.

Example 3 A toner was produced and developed under the same conditions as in Example 1 except that the blade of the developing device was made of urethane rubber and the developing sleeve was made of stainless steel. The results are also shown in Table 1.

Example 4 A charge controlling agent was trade name: NX-
The production and development of the toner were performed under the same conditions as in Example 3 except that 434 (manufactured by Clariant Japan) was used. The results are also shown in Table 1. The toner has a circularity of 0.1.
93.

Example 5 A toner was prepared under the same conditions as in Example 4 except that the amount of the polypropylene wax added was 1 part, and the pigment was carbon black, and the trade name was Toner Magenta E02 (manufactured by Clariant Japan). Was produced and developed, and the results are shown in Table 1. The circularity of this toner was 0.92.

Example 6 A toner was produced and developed under the same conditions as in Example 5 except that the toner was pulverized using a Kryptron manufactured by Kawasaki Heavy Industries, Ltd. in the pulverization step of the toner. The results are shown in Table 1. Also described. The circularity of this toner was 0.96.

Example 7 Production and development of a toner were performed under the same conditions as in Example 1 except that the developing sleeve of the developing device was made of silicone rubber. The results are also shown in Table 1.

(Comparative Example 1) Toner was produced and developed under the same conditions as in Example 1 except that the blade of the developing device was made of urethane rubber and the developing sleeve was made of silicone rubber. The results are also shown in Table 1.

Comparative Example 2 A general polyester resin (trade name: FC-
664, manufactured by Mitsubishi Rayon Co., Ltd.), and toner production and development were performed under the same conditions as in Example 1. The results are also shown in Table 1. The circularity of this toner was 0.92.

(Comparative Example 3) A general polyester resin (trade name: HP-
313, manufactured by Nippon Gosei Co., Ltd.), and toner production and development were performed under the same conditions as in Example 1. The results are also shown in Table 1. The circularity of this toner was 0.93.

Comparative Example 4 A toner was produced and developed under the same conditions as in Comparative Example 2 except that the toner was pulverized using a Kryptron manufactured by Kawasaki Heavy Industries, Ltd. in the pulverization step of the toner. Also described. The circularity of this toner was 0.96.

[0037]

[Table 1]

As is clear from Table 1, in the developing method of the example, the charge amount and image density hardly change even after the forced stirring for 30 minutes, and the charge characteristics are good. Also,
It can be seen that there is almost no change in the image density of the background, and the occurrence of fog is suppressed. Further, it was confirmed that no fusion of the toner to the blade occurred and the durability was good.

On the other hand, in Comparative Example 1, since the developing sleeve was made of silicone rubber and the blade was made of urethane rubber while using the same toner as in Example 1, charging failure occurred and a toner layer could not be formed. . As a cause of this, it is presumed that there is a problem in the chargeability between the urethane-extended polyester resin in the toner and the blade made of urethane rubber. In particular, when the developing sleeve is made of a non-metallic material, the charge given to the toner is significantly It is thought that it is decreasing. In Comparative Examples 2 and 3, since no urethane-extended polyester resin was used, the silica fine particles were buried in the toner particles after forcible stirring, resulting in blade fusing, resulting in fog and a decrease in image density. doing. In Comparative Example 4, fusion of the toner to the blade was relatively slight because the toner was spherical. In addition,
Even when the forced stirring was performed for 60 minutes using the toner having a circularity of 0.96 in Example 6, no problem occurred in the image density, the background density, and the blade fusion. On the other hand, in the toner of Example 1 having a circularity of 0.93,
After the forced stirring for 60 minutes, slight blade fusion occurred.

[0040]

As described above, according to the developing method using the dry non-magnetic one-component toner of the present invention, not only the fixability and the durability of the toner can be improved, but also the toner can be improved. And the occurrence of poor charging and fogging can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an example of a developing device for carrying out the present invention.

[Explanation of symbols]

 3 ... toner, 4 ... blade, 5 ... developing sleeve.

Claims (2)

[Claims] 1. A developing method using a dry non-magnetic one-component toner in which a layer of a dry non-magnetic one-component toner is formed on the developing sleeve by a developing sleeve and a blade facing the developing sleeve. The dry non-magnetic one-component toner has a polyester resin having a high molecular weight formed by urethane extension as a main binder component, and one of the developing sleeve and the blade is made of metal and the other is a synthetic resin or natural rubber or a rubber thereof. A developing method using a dry non-magnetic one-component toner, which is a mixture. 2. The developing method according to claim 1, wherein the non-magnetic one-component toner is spherical.