JPH0954454A - Method for preserving developer and vessel therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a developer preserving vessel and to provide a preserving method by which a two-component developer consisting of a toner and a carrier maintains a stable quantity of electric charges and does not cause image defects such as fog even in preservation over a long period of time. SOLUTION: When a developer consisting of a carrier and a toner consisting essentially of a resin and a colorant is preserved, the resin is polyester resin having 30-80mgKOH/g acid value and 300-700mgKOH/g saponification value and the developer is housed in a packing material formed with a filmlike member having <=3.0cc/m<2> steam permeability and 10-150μm film thickness.

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 such as a copying machine or a printer, and more particularly to a method of storing a developer using a polyester resin as a toner.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic image forming method has been widely used in various printers as well as copying machines. This image forming method can be roughly classified into a system using a so-called two-component developer composed of a toner and a carrier, and a system using a one-component developer composed of only a toner containing no carrier. The two-component developer, which is used by mixing the carrier and the toner, is widely used because it can easily generate the charge and the charge amount can be easily controlled.

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

However, since this polyester resin has a large number of acid component residues and ester groups in the molecule, it has a higher water adsorption compared to the styrene-acrylic resin. As a result, when a two-component developer is prepared by mixing a toner and a carrier and stored for a long period before use, there is a risk of leakage of the retained charges due to various transportation or fluctuations in water in the storage environment. May occur, causing a decrease in the amount of charge and causing fog or the like in the initial image during use. Also,
There is also a problem that the toner is likely to cause blocking due to plasticization due to water.

[0005]

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

[0006]

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

[1] A method of storing a developer comprising a carrier, a toner comprising at least a resin and a colorant, wherein the resin has an acid value of 30 to 80 KOHmg / g and a saponification value of 300 to 700 KOHmg / g. It is a polyester resin and has a water vapor transmission rate of 3.0 (c
c / m < ² >) or less, and a method for storing a developer, characterized by storing in a packaging material formed of a film-shaped member having a film thickness of 10 to 500 [mu] m.

[2] Carrier and at least an acid value of 3
0-80KOHmg / g, saponification value 300-700KO
A container for storing a developer in which a toner composed of a Hmg / g polyester resin and a colorant is mixed, the 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-shaped member having a thickness of 0 to 500 μm.

As a result of earnest studies, the present inventors have found that toner using a polyester resin has a large adsorptivity of water to acid groups existing as a residue and ester groups existing in the molecule, so that so-called air permeation is prevented. It was found that even when stored in a shut-off state, water accumulates and a large charge leak phenomenon occurs. In order to eliminate the influence of this moisture, it was found that it is necessary to reduce the permeability of water vapor, not just the air permeability, and the present invention has been completed.

The structure of the present invention will be described in more detail below.

Regulations of water vapor transmission rate and packaging conforming thereto
Material In the present invention, the water vapor transmission rate refers to the amount of water vapor transmission 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 permeability is ASTM F-382 or JIS Z-020.
It is measured by the method shown in 8.

Vinylidene chloride resin is preferably used as a material for blocking air permeability.

Further, it is preferable that these resins are used after being formed into a film. The reason for this is that it is possible to increase the film thickness and mold and use a container such as a so-called bottle, but when the container is discarded after the developer is installed in the machine, the bulk of the industrial waste becomes large. However, there is a problem that the cost of the container increases, which is not preferable.

When used as a film, the film thickness of this resin is preferably 10 to 150 μm. When the thickness is less than this, the blocking effect is reduced, and when the thickness is large, the flexibility as a film is reduced, and there is a problem that it is difficult to use. Furthermore, it is also a preferable mode to use a film laminated with a polypropylene film or a polyethylene film, instead of the resin alone. That is, when a vinylidene chloride resin is used, the material itself has a high triboelectric charging property, and after charging the developer, triboelectric charging with the material occurs, which causes a problem of changing the charge amount of the developer. Have Therefore, by using a film laminated with a resin having low polarity such as polypropylene or polyethylene, it is possible to reduce the influence of the triboelectric chargeability of the container on the developer. The film thickness for this lamination is preferably 10 to 50 μm on one side. Further, the laminate may be applied not only to the surface in contact with the developer but also to both surfaces. The total film thickness including the laminate is 20 to 150 μm, preferably 50 to 100 μm.

Further, the airtightness may be enhanced by laminating aluminum or the like for use. However, in this method, since the metal material and the resin material are mixed,
There is a possibility that it will become an obstacle when reusing wastes in recent years, and it is preferable to laminate with the above-mentioned resin.

Composition 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 is preferred, especially 400-600 KOHmg / g
Is preferred.

Here, the saponification value indicates the number of milligrams of potassium hydroxide necessary for saponifying 1 g of the 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 excessively large, the amount of so-called polar groups becomes excessive and the electric charge cannot be stably held.

The acid value is the number of milligrams of potassium hydroxide necessary for neutralizing the carboxyl groups present in 1 g of the sample, and is the amount of the carboxyl groups present at the so-called terminals. If this amount is small, the adhesiveness to paper decreases, and the fixability decreases. On the other hand, when the amount is too large, it means that the molecular weight is low, and the offset property is deteriorated.

These saponification values and acid values are JIS K 00.
It can be measured by the method specified in 70.

To form 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,
Bivalent 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-naphthalenetricarnoic 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 empol trimer, or acid anhydrides thereof. It can be formed by a polycondensation reaction with a polyvalent carboxylic acid shown in.

By using a trivalent or higher valent monomer,
It may be crosslinked. In this case, the chloroform-insoluble content is preferably set to 0.5 to 20% by weight.

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

The sample was finely pulverized, and 5.00 g of the sample passed through a 40-mesh sieve was used as a filter aid for radiolite (#
700) 5.00 g and add these to 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, a 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 uniformly precoated, and the contents in the container are poured into a filter paper tightly adhered with a small amount of chloroform, followed by filtration. The container is further washed with 100 ml of chloroform so that there is no 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 content (%) = (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 by a Koka type 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) or the like.
It is measured when the temperature is raised from room temperature to 100 ° C under the condition of 10 ° C / min, then cooled, and the temperature is raised again under the same conditions. It is the maximum between the extension line of the baseline and the peak apex. The intersection with the tangent line indicating the slope is shown as the glass transition temperature.

Constitution of Toner Basically known constitution can be used for constitution other than resin. That is, the colorant is not particularly limited, and various conventionally known materials are used. Examples include 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. Mixtures of can also be used.
The content of these colorants in the toner is preferably 0.5 to 20% by weight.

Other additives include, for example, charge control agents such as salicylic acid derivatives and azo metal complexes, low molecular weight polyolefins, quantification improving agents such as kauna wax. In addition, it is desirable to externally add inorganic fine particles such as silica, and the existing fine particles are preferably subjected to a hydrophobic treatment with a silane coupling agent or the like.

The carrier constituting the carrier is not particularly limited, but any of iron powder, ferrite, magnetite and resin-coated ones 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 that coats the carrier, a styrene resin, an acrylic resin, a styrene-acrylic resin, or the like can be used. From the viewpoint of durability and developability, it is preferable to coat the resin with a thickness of 1.0 μm to 5.0 μm in terms of average film thickness. The average film thickness is Microtrack SR
Based on the weight average particle diameter of the carrier core measured by AMK-II (manufactured by Nikkiso Co., Ltd.), the carrier core is assumed to be a true sphere, and the volume is calculated from the weight by the specific gravity of the carrier core and the coating material. Can be calculated by

The method for coating the resin is not particularly limited, and a method of electrostatically adhering the resin fine particles by a dry method and then applying a mechanical impact force to form a film, a method of applying a heat after attaching the fine particles Any of a method of applying and melting to coat the resin, a method of dissolving the resin in a solvent and coating and drying the resin may be used.

[0030]

The present invention will be described in detail below with reference to examples, but the 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 3 on both sides of vinylidene chloride film (film thickness = 25 μm)
A 0 μm polypropylene film was laminated to obtain a film having a total film thickness of 85 μm. The developer storage container was formed by heat sealing using this film. This is referred to as "storage container 1". The water vapor permeability of this film is 0.7 cc / m ² in terms of 30 μm.

Storage container 2 2 on both sides of vinylidene chloride film (film thickness = 35 μm)
A 5 μm high-density polyethylene film was laminated to obtain a film having a total film thickness of 85 μm. The developer storage container was formed by heat sealing using this film. This is referred to as "storage container 2". The water vapor permeability of this film is 0.7 cc / m ² in terms of 30 μm.

Storage container 3 3 on both sides of vinylidene chloride film (film thickness = 15 μm)
A 0 μm polypropylene film was laminated to obtain a film having a total film thickness of 75 μm. The developer storage container was formed by heat sealing using this film. 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 a total film thickness of 55 μm. The developer storage container was formed by heat sealing using this film. This is referred to as "storage container 4". The water vapor permeability 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 is 3.3 cc / in terms of 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., chloroform insoluble matter = 2%, and 100 parts of a polyester resin prepared from neopentyl glycol, ethylene glycol, 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 = 3300) were mixed, kneaded, crushed and classified, and then 1.0 wt% of hydrophobic silica was added to obtain a volume average particle size of 8.3 μm toner was obtained. Next, a styrene-acrylic resin-coated ferrite carrier having a volume average particle size of 65 μm was mixed 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 matter = 5% neopentyl glycol, ethylene glycol, 1,2-propylene glycol, succinic acid,
100 parts of polyester resin prepared from terephthalic acid and 1,2,4-benzenetricarboxylic acid anhydride, 10 parts of carbon black and 3 parts of low molecular weight polypropylene (number average molecular weight = 2600) are mixed, kneaded, crushed, After classification, 1.0% by weight of hydrophobic silica was added to obtain a toner having a volume average particle diameter of 8.2 μm. Next, a styrene-acrylic resin-coated ferrite carrier having a volume average particle size of 65 μm was mixed 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-anhydrous
100 parts of 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, ground and classified, and then 1 part of hydrophobic silica was mixed. ．
0% by weight was added to obtain a toner having a volume average particle size of 8.1 μm. Next, a styrene-acrylic resin-coated ferrite carrier having a weight average particle size of 65 μm was mixed to prepare a developer having a toner concentration of 6%. This is referred to as “Developer 3”.

( Evaluation ) "Developer 1" to "Developer 3"
Was put into the above-mentioned "storage container 1" to "storage container 4" and "comparison storage container 1" and sealed by heat sealing. Then, the film was stored in an environment of 40 ° C. and 90% RH for 30 days, and the change in the charge amount before and after the storage and the presence or absence of image defects in image printing, especially the fog generated in the image were evaluated. In addition, the print evaluation is performed by Konica U-MIX, a copying machine manufactured by Konica Corporation.
Using 6192, normal temperature and normal humidity environment (23 ° C / 50% RH)
Was carried out. The results are shown in the table below.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

There is no problem in the combination of the developers 1 to 3 with the storage containers 1 to 4 in the present invention, but in the combination with the comparative storage container 1 outside the present invention, both the charge amount and the fogging occur. I understand.

[0044]

EFFECTS OF THE INVENTION According to the present invention, a two-component developer comprising a toner and a carrier retains a stable charge amount even during long-term storage and does not cause image defects such as fog. A container and a storage method can be provided.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiaki Kobayashi 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company

Claims (2)

[Claims] 1. A method for storing a developer comprising a carrier and a toner comprising at least a resin and a colorant, wherein the resin has an acid value of 30 to 80 KOHmg / g and a saponification value of 30.
The polyester resin is 0 to 700 KOHmg / g, and the developer has a water vapor transmission rate of 3.0 (cc / m).
² ) A method for storing a developer, which is characterized in that it is stored in a packaging material formed of a film-shaped member having a film thickness of 10 to 150 μm. 2. A carrier and at least an acid value of 30-8.
0KOHmg / g, saponification value 300-700KOHmg
Is a container for storing a developer in which a toner composed of a polyester resin and a colorant of 1 / g is stored, 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 is used.
A developer storage container, which is formed of a film-shaped member having a thickness of 150 μm.