JP3538790B2 - Method of storing developer and container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in an electrophotographic image forming method of a copying machine, a printer or the like, and more particularly to a method of preserving a developer using a polyester resin as a toner.

[0002]

2. Description of the Related Art Conventionally, electrophotographic image forming methods have been widely used not only for copying machines but also for various printers and the like. This image forming method can be roughly classified into a method using a so-called two-component developer composed of a toner and a carrier, and a method using a one-component developer composed only of a toner without using a carrier. A two-component developer using a mixture of a carrier and a toner is widely used because it can easily generate a charge and the charge amount can be easily controlled.

As a resin used for the toner, a polyester resin is widely used from the viewpoint of fixability. Since the polyester resin has a carboxyl group or an ester group, the polyester resin has good adhesiveness to paper, and has good fixing characteristics without occurrence of offset.

However, since the polyester resin has many residues of acid components and ester groups in the molecule, the adsorption of water is higher than that of the styrene-acryl resin. As a result, when a two-component developer is prepared by mixing a toner and a carrier and stored for a long period of time before use, leakage of electric charges held due to fluctuations in moisture in various transportation or storage environments may occur. This may cause a decrease in the charge amount and fog or the like may occur in an initial image during use. Also,
There is also a problem that the toner is liable to cause blocking due to plasticization by moisture.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a two-component developer comprising a toner and a carrier, which maintains a stable charge amount even during long-term storage, and reduces image defects such as fog. To provide a developer storage container and a storage method that do not cause odor.

[0006]

The object of the present invention is achieved by adopting the following constitution.

[1] In a method for preserving a developer comprising a toner comprising a carrier, at least a resin and a colorant, the resin has an acid value of 30 to 80 KOH mg / g and a saponification value of 300 to 700 KOH mg / g. A certain polyester resin, and the developer has a water vapor transmission rate of 3.0 (c
c / m ² ) A method for preserving a developer, wherein the developer is housed in a packaging material formed of a film-like member having a thickness of 10 to 500 μm.

[2] A carrier and at least an acid value of 3
0-80 KOHmg / g, saponification value 300-700 KO
A container for storing a developer in which a toner composed of a polyester resin of Hmg / g and a colorant is mixed, and is made of a material having a water vapor transmission rate of 3.0 (cc / m ² ) or less and a film thickness of 1
A developer storage container formed of a film member having a thickness of from 0 to 500 μm.

The inventors of the present invention have conducted intensive studies and have found that a toner using a polyester resin has a high water-absorbing property for an acid group existing as a residue and an ester group existing in a molecule. It has been found that even when stored in a cut-off state, moisture accumulates and a large amount of charge leakage occurs. In order to eliminate the influence of moisture, it was found that it was necessary to reduce not only the permeability of air but also the permeability of water vapor, and the present invention was completed.

Hereinafter, the configuration of the present invention will be described more specifically.

Specification of water vapor transmission rate and packaging conforming thereto
Material In the present invention, the water vapor transmission rate indicates the amount of permeated water vapor per unit area when the film thickness is 30 μm when left in an environment of 40 ° C. and 90% RH for 24 hours. This water vapor transmission rate is determined by ASTM F-382 or JIS Z-020.
It is measured by the method shown in FIG.

As a material for blocking air permeability, a vinylidene chloride resin is preferably used.

Further, it is preferable that these resins are used after being formed into a film. As a reason for this, it is possible to increase the film thickness and form and use a container such as a so-called bottle, but when the container is disposed after the developer is installed in the machine, the volume of industrial waste increases and However, there are problems such as an increase in cost as a container, which is not preferable.

When used as a film, the resin preferably has a thickness of 10 to 150 μm. If the thickness is less than this, the blocking effect is reduced, and if the thickness is large, the flexibility of the film is reduced, and there is a problem that it is difficult to use. Furthermore, it is also a preferable embodiment to use a film laminated with a polypropylene film or a polyethylene film instead of using the resin alone. In other words, when vinylidene chloride resin is used, the material itself has a high triboelectric charging property, and the triboelectric charging with the material occurs after the developer is filled, and the charge amount of the developer is changed. Have. Therefore, by using a film laminated with a low-polarity resin such as polypropylene or polyethylene, it is possible to reduce the influence of the triboelectricity of the container on the developer. When this lamination is performed, the film thickness on one side is preferably 10 to 50 μm. Lamination may be performed not only on the surface in contact with the developer but also on both surfaces. The total film thickness including the lamination is 20 to 150 μm, preferably 50 to 100 μm.

Further, the airtightness may be enhanced by laminating aluminum or the like. However, in this method, a metal material and a resin material are mixed, so that
There is a possibility that it may become an obstacle when reusing waste in recent years, and the configuration of laminating with the above-described resin is more preferable.

Structure of Polyester Resin The polyester resin of the present invention has an acid value of 30 to 80 KOH.
mg / g is preferable, and 40 to 70 KOH mg / g is particularly preferable. Furthermore, the saponification value is 300-700 KOHmg.
/ G, preferably 400 to 600 KOH mg / g.
Is preferred.

Here, the saponification value indicates the number of milligrams of potassium hydroxide required to saponify 1 g of a sample, and indicates the so-called amount of ester groups present in the molecule. When the amount is small, the amount of the ester group is small, and the adhesiveness to paper is reduced. On the other hand, when the saponification value is too large, the amount of the so-called polar group is too large and the charge cannot be stably held.

The acid value indicates the number of milligrams of potassium hydroxide necessary for neutralizing the carboxyl group present in 1 g of the sample, and indicates the so-called amount of the carboxyl group existing at the terminal or the like. If this amount is small, the adhesiveness to paper decreases, and the fixability decreases. On the other hand, if it is excessive, it means that the molecular weight is low, and the offset property is reduced.

These saponification values and acid values are determined according to JIS K 00
It can be measured by the method specified in No. 70.

In order to constitute these resins, polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene Glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,4-cyclohexanediol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol,
Dihydric alcohols such as bisphenol A and hydrogenated bisphenol A, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,2 4-butanetriol, 1,2,5-
Pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl1,2,4-butanetriol, trimethylolethane, trimethylolpropane,
Polyhydric alcohols such as trihydric or higher alcohols such as 1,3,5-trihydroxymethylbenzene, and maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid acid,
Succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecylsuccinic acid, n-dodecenylsuccinic acid, isododecylsuccinic acid, isododecenylsuccinic acid,
2 such as n-octylsuccinic acid and n-octenylsuccinic acid;
Carboxylic acids or their anhydrides, 1,2,2
4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-
Hexanetricarboxylic acid, 1,3, -dicarboxyl-
2-methyl-2-methylenecarboxypropane, 1,
Trivalent or higher carboxylic acids such as 2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octenetetracarboxylic acid, pyromellitic acid, and empole trimer or acid anhydrides thereof Can be formed by a polycondensation reaction with polyvalent carboxylic acids shown in (1).

Further, by using a monomer having three or more valences,
It may be crosslinked. In this case, the chloroform-insoluble content is preferably 0.5 to 20% by weight.

The chloroform-insoluble matter can be measured by the following method.

The sample was pulverized, and 5.00 g of the sample passed through a 40-mesh sieve was added to radiolite (#) as a filter aid.
700) 5.00 g are added and these are placed in a 150 ml container. Then, 100 g of chloroform is added, and the sample is sufficiently rotated in a ball mill stand for 5 hours or more to be dissolved in chloroform. Thereafter, filter paper (No. 2) having a diameter of 7 cm was placed in the pressure filter, and 5.00 was placed thereon.
g of radiolite is pre-coated uniformly, and the contents in the container are poured into a filter paper tightly adhered with a small amount of chloroform, followed by filtration. The vessel is further washed with 100 ml of chloroform to remove any residue on the wall. After the filtration is completed, the residue on the filter paper is washed with 100 ml of chloroform, and the filtration is repeated. The filter paper and the residue thereon and the radiolite are all vacuum dried on aluminum foil. The conditions are 80 to 100 ° C. and 100 mmHg for 10 hours. The total weight Ag of the dried product obtained by the above operation is measured, and the chloroform-insoluble matter (% by weight) is calculated from the following equation.

Chloroform insoluble matter (%) = (A-weight of filter paper-weight of radiolite) /5.00×100 Further, the softening point of the resin is preferably 95 to 170 ° C. This softening point can be measured with a Koka flow tester. The glass transition temperature of the resin is 50 to
Those at 80 ° C. are preferred. This glass transition temperature can be measured by a differential scanning calorimeter, and specifically, DSC-
7 (manufactured by Pekin Elmer).
The temperature is measured when the temperature is raised from room temperature to 100 ° C. at a rate of 10 ° C./min, then cooled, and the temperature is raised again under the same condition. The maximum length between the extension of the baseline and the peak from the baseline to the peak apex is measured. The point of intersection with the tangent line indicating the slope is shown as the glass transition temperature.

Structure of Toner Basically, a known structure can be used other than the resin. That is, the colorant is not particularly limited, and various conventionally known materials are used. For example, carbon black, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, macalite green oxalate, lamp black, rose bengal, and the like. Can also be used.
The content of these colorants is preferably 0.5 to 20% by weight in the toner.

Examples of other additives include charge control agents such as salicylic acid derivatives and azo metal complexes, and quantitative improvers such as low molecular weight polyolefins and kaunauba wax. Further, it is desirable to externally add inorganic fine particles such as silica, and the fine particles are preferably subjected to a hydrophobic treatment with a silane coupling agent or the like.

Structure of Carrier The carrier is not particularly limited, but any of iron powder, ferrite, magnetite and those coated with resin can be used.

The carrier preferably has a specific gravity of 3 to 7, a weight average diameter of 20 to 150 μm, and more preferably 30 to 65 μm. As the resin for coating the carrier, a styrene resin, an acrylic resin, a styrene-acryl resin, or the like can be used. From the viewpoints of durability and developability, it is preferable to coat the resin with a carrier to a thickness of 1.0 μm to 5.0 μm in terms of average film thickness. The average thickness is Microtrack SR
A Based on the weight average particle diameter of the carrier core measured by MK-II (manufactured by Nikkiso Co., Ltd.), assuming that the carrier core is a true sphere, the volume is calculated from the weight by the specific gravity of the carrier core and the coating material. Can be calculated.

The method of coating the resin is not particularly limited. A method in which fine resin particles are electrostatically adhered in a dry manner and then a mechanical impact force is applied to form a film, and a method in which the fine particles are adhered and then heated. And a method in which the resin is melted and coated, or a method in which the resin is dissolved in a solvent and applied and dried.

[0030]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.

(Production Example of Developer Storage Container) Storage Container 1: Vinylidene chloride film (film thickness = 25 μm)
A 0 μm polypropylene film was laminated to obtain a film having an overall thickness of 85 μm. The film was heat-sealed to form a developer storage container. This is referred to as “storage container 1”. The water vapor transmission rate of this film is 0.7 cc / m ² in terms of 30 μm.

Storage container 2 Both sides of vinylidene chloride film (film thickness = 35 μm)
A 5 μm high-density polyethylene film was laminated to obtain a film having an overall thickness of 85 μm. The film was heat-sealed to form a developer storage container. This is referred to as “storage container 2”. The water vapor transmission rate of this film is 0.7 cc / m ² in terms of 30 μm.

Preservation container 3 A vinylidene chloride film (film thickness = 15 μm)
A 0 μm polypropylene film was laminated to obtain a film having a total thickness of 75 μm. The film was heat-sealed to form a developer storage container. This is referred to as “storage container 3”. The water vapor transmission rate of this film is 1.2 cc / m ² in terms of 30 μm.

Storage container 4 2 on both sides of vinylidene chloride film (film thickness = 15 μm)
A 0 μm polypropylene film was laminated to obtain a film having an overall thickness of 55 μm. The film was heat-sealed to form a developer storage container. This is referred to as “storage container 4”. The water vapor transmission rate of this film is 1.8 cc / m ² in terms of 30 μm.

Comparative Storage Container 1 A developer storage container was formed by heat sealing using a high-density polyethylene film (film thickness = 80 μm). This is referred to as “comparison storage container 1”. The water vapor transmission rate of this film was 3.3 cc / 30 μm.
m ² .

Developer Preparation Example 1 Acid value = 70 KOHmg / g, Saponification value = 590 KOHmg
/ G, Tg = 69 ° C., softening point = 146 ° C., 100 parts of a polyester resin prepared from neopentyl glycol, ethylene glycol, terephthalic acid, and 1,2,4-benzenetricarboxylic anhydride having a chloroform-insoluble content of 2%. , 10 parts of carbon black and 3 parts of low molecular weight polypropylene (number average molecular weight = 3300) were mixed, ground, crushed and classified, and then 1.0% by weight of hydrophobic silica was added. An 8.3 μm toner was obtained. Next, the mixture was mixed with a ferrite carrier having a volume average particle diameter of 65 μm coated with a styrene-acryl resin to prepare a developer having a toner concentration of 6%. This is referred to as “Developer 1”.

Developer Preparation Example 2 Acid value = 59 KOHmg / g, Saponification value = 460 KOHmg
/ G, Tg = 64 ° C., softening point = 148 ° C., chloroform-insoluble content = 5% neopentyl glycol, ethylene glycol, 1,2-propylene glycol, succinic acid,
100 parts of a polyester resin prepared from terephthalic acid and 1,2,4-benzenetricarboxylic anhydride, 10 parts of carbon black, and 3 parts of low molecular weight polypropylene (number average molecular weight = 2600) were mixed, kneaded, pulverized, After classification, 1.0% by weight of hydrophobic silica was added to obtain a toner having a volume average particle size of 8.2 μm. Next, the mixture was mixed with a ferrite carrier having a volume average particle diameter of 65 μm coated with a styrene-acryl resin to prepare a developer having a toner concentration of 6%. This is referred to as “Developer 2”.

Developer Preparation Example 3 Acid value = 71 KOHmg / g, Saponification value = 620 KOHmg
/ G, Tg = 67 ° C., softening point = 143 ° C., chloroform-insoluble matter = 5% neopentyl glycol, ethylene glycol, succinic acid, terephthalic acid, 1,2,4-anhydride
100 parts of a polyester resin prepared from benzenetricarboxylic acid, 10 parts of carbon black, and 3 parts of low molecular weight polypropylene (number average molecular weight = 4600) were mixed, kneaded, pulverized, and classified. .
By adding 0% by weight, a toner having a volume average particle size of 8.1 μm was obtained. Next, the mixture was mixed with a ferrite carrier coated with a styrene-acrylic resin and having a weight average particle diameter of 65 μm to prepare a developer having a toner concentration of 6%. This is designated as “Developer 3”.

( Evaluation ) The above-mentioned "developer 1" to "developer 3"
Was placed in the above-mentioned "storage container 1" to "storage container 4" and "comparison storage container 1", and sealed by heat sealing. Then, it was stored in an environment of 40 ° C. and 90% RH for 30 days, and the change in charge amount before and after the storage and the presence or absence of image defects in image printing, particularly fog generated in the image were evaluated. In addition, the printing evaluation was performed using a Konica Copier, Konica U-BIX.
Normal temperature and normal humidity environment (23 ° C / 50% RH) using 6192
Was carried out. The results are shown in the table below.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

Although there is no problem in the combination of the developers 1 to 3 with the storage containers 1 to 4 in the present invention, there is a problem in both the charge amount and the fog in the combination with the comparative storage container 1 outside the present invention. You can see that.

[0044]

According to the present invention, in a two-component developer comprising a toner and a carrier, the developer can maintain a stable charge amount even during long-term storage, and does not generate image defects such as fog. Containers and storage methods can be provided.

Continuation of the front page (72) Inventor Yoshiaki Kobayashi Konica Corporation, 2970 Ishikawa-cho, Hachioji-shi, Tokyo (56) References JP-A-7-49587 (JP, A) JP-A-6-278775 (JP, A) JP-A-5-113688 (JP, A) JP-A-6-130566 (JP, A) JP-A-6-118788 (JP, A) JP-A-6-278740 (JP, A) 308783 (JP, A) JP-A-61-227048 (JP, A) JP-A-2-302445 (JP, A) Japanese Utility Model Laid-Open No. 1-76219 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08-9/087 B65D 81/18-81/30

Claims (2)

(57) [Claims] In a method for preserving a developer comprising a carrier, a toner comprising at least a resin and a colorant, the resin has an acid value of 30 to 80 KOHmg / g and a saponification value of 30.
0-700 KOHmg / g polyester resin and the developer has a water vapor transmission rate of 3.0 (cc / m
² ) A method for storing a developer, wherein the developer is stored in a packaging material formed of a film-like member having a thickness of 10 to 150 μm. 2. A carrier having an acid value of at least 30 to 8
0KOHmg / g, saponification value 300-700KOHmg
/ G is a container for storing a developer in which a toner comprising a polyester resin and a colorant is mixed, and a material having a water vapor transmission rate of 3.0 (cc / m ² ) or less and a film thickness of 10 to 10 cc / m ² is used.
A developer storage container formed of a 150 μm film-shaped member.