JP3403848B2 - Paint composition, developing device, and method of manufacturing developing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition, and more particularly to a coating composition which suppresses / prevents gelation and prolongs usable time.

[0002]

2. Description of the Related Art As is well known, paints are applied to the surface of various base materials in order to impart aesthetics, weather resistance, stain resistance or corrosion resistance, and are widely used in various fields. There is. And, of this kind of paint (paint composition),
For example, a one-pack type coating composition obtained by using a thermoplastic elastomer such as a polyester elastomer or a vinyl elastomer as a resin component and dissolving the resin component in an organic solvent basically causes a chemical reaction to form a coating film. Not accompanied.
Therefore, in general, the paint is easy to prepare and handle, and the storage stability is relatively good. In addition, as the thermoplastic elastomer, a resin such as a styrene-based elastomer, an olefin-based elastomer, a polyamide-based elastomer, a urethane-based elastomer, or a copolymer composed of two or more of them may be used as a resin, depending on the use or the mode of use. A coating composition as a component is also known.

Further, in a developing device provided with a mechanism for developing an electrostatic latent image formed on a latent image holding member with toner carried on a developing roller arranged facing the latent image holding member. The developing roller is made of an elastomer such as urethane or nylon. This structure is excellent in mechanical strength, but has a problem that the characteristics deteriorate with time. For example, the toner adheres to the surface of the developing roller, causing a decrease in the amount of charge of the toner, which causes a problem of image deterioration.

[0004]

As described above, the thermoplastic elastomer has relatively good storage stability because it does not undergo a chemical reaction at the time of forming a coating film. In some cases, it easily gels. For example, in the case of a coating composition using a fluoroelastomer as a resin component, gelation is observed after standing for several tens of hours at room temperature (room temperature), and gelation occurs after standing for several hours at a low temperature of about 10 ° C. It occurs and its use is substantially constrained. That is, since the coating film of the fluorine-based elastomer has excellent weather resistance and stain resistance, it is used, for example, for building structural materials such as roofs and bridges that are exposed directly to the outside air, or developing rollers for copying machines that are easily exposed to ozone and the like. It is expected to be applied to applications. However, a coating composition containing a fluoroelastomer as a resin component starts gelation in a relatively short time after its preparation, making it difficult to form a uniform coating film. In the case of a product, the agglomeration of the pigment makes it more difficult to form the uniform coating film, and the usable time is short.

In any case, the storage stability of the coating composition, the uniformity of the coating film, etc. are strongly demanded from the practicality when the coating composition is used as an exterior / coating agent for a structural base material. However, in this respect, it is difficult to say that the conventional coating composition is sufficiently satisfactory even when the resin component is a thermosetting resin or even when it is a thermoplastic elastomer.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a coating composition in which gelation of the composition after standing at room temperature is suppressed and the usable time thereof is significantly increased. .

It is another object of the present invention to provide a developing device equipped with a developing roller that does not deteriorate in characteristics even when used for a long time, and a method of manufacturing the developing device.

[0008]

A coating composition according to the present invention comprises a fluorine-based elastomer as a main component and a polyvinyl pigment.
A coating composition prepared by using a resin component containing loridone and an organic solvent component as components, wherein
Polyvinylpyrrolidone occupies 01 to 50 mass%.

[0009]

The present invention has been accomplished on the basis of the following logic and experiment / examination. That is, it is considered that the gelation phenomenon in the polymer solution is generally caused by the particles (molecules) in the solution being entangled with each other and having a three-dimensional net-like or honeycomb-like structure. Based on this reasoning, a substance that inhibits the entanglement of molecular chains in the polymer solution may coexist. From such a viewpoint, the inventors of the present invention have made extensive studies, and as a result, in a coating composition including a fluorine-based elastomer and an organic solvent that dissolves the fluorine-based elastomer as an essential component, a predetermined amount of polyvinylpyrrolidone. As a resin component, when further mixed and dissolved, it was confirmed that the gelation phenomenon of the coating composition is easily suppressed / prevented, and that it functions as a stable coating composition after preparation, and the present invention has been achieved. Is.

More specifically, polyvinylidene fluoride,
Examples thereof include polyvinylidene fluoride, hexafluoropropylene-tetrafluoroethylene-vinylidene fluoride copolymer, modified fluororesin, polystyrene, poly-p-chlorostyrene, and polymers of styrene such as polyvinyltoluene or a substitution product thereof. Then, of these organic binders, the present invention is particularly effective when the main resin component is an organic binder that is hardly soluble in an organic solvent.

In the present invention, polyvinylpyrrolidone having a bond represented by the following formula --CO--N = in the molecule was particularly effective for preventing gelation. Here, the degree of polymerization of the nitrogen-containing vinyl polymer is at most about 200,000, preferably about 100 to 80,000, in consideration of solubility. The composition ratio of the nitrogen-containing vinyl polymer is 0.01 to 50% by mass in the resin component containing the organic binder of the coating composition, preferably
The amount is 0.1 to 10% by mass, more preferably 0.5 to 5% by mass. The composition ratio of the nitrogen-containing vinyl polymer is 0.01% by mass.
If it is less than 50% by weight, the effect of addition and blending is not recognized, and if it exceeds 50% by mass, the strength of the coating film formed tends to be deteriorated.

In the coating composition according to the present invention, examples of the organic solvent for dissolving the resin component include ketones such as methyl ethyl ketone, acetone and methyl isobutyl ketone, ethers such as methyl ethyl ether and diethyl ether, benzene and toluene. , Aromatic solvents such as xylene, aliphatic solvents such as n-hexane and heptane, esters such as ethyl acetate, alcohols such as methanol, ethanol and isopropyl alcohol,
Examples thereof include halogen solvents such as carbon tetrachloride, trichloroethylene, and dichloroethane, or a mixture of two or more kinds. Furthermore, in the coating composition according to the present invention, the organic binder, the nitrogen-containing vinyl polymer,
And the organic solvent is an essential component, but if necessary, a surface regulator, an ultraviolet absorber, a thickener, a dye, a pigment,
Conductive powder, metal powder, deterioration inhibitor, precipitation inhibitor, etc. may be added as appropriate. Then, in preparing the coating composition according to the present invention, a dispersing device such as a three-roller, an attractor, a ball mill, a sand mill, a paint shaker, and a nanomizer can be used.

Although the coating composition according to the present invention varies depending on its use or application amount, the following use modes are generally adopted. That is, the surface of the structural base material made of plastics, rubbers, metals, ceramics, or the like is subjected to cleaning treatment or etching treatment (roughening) as needed, and further coupling agent or After surface treatment with a chelating agent, etc., air spray, airless spray, electrostatic spray, shower coat, dip coating, roll coating, brush coating, etc.

Particularly, when the coating composition of the present invention is used for forming the surface layer of the developing roller of the developing device, a fluorine-based elastomer is effective as the organic binder. Here, since the fluorine-based elastomer does not adhere to the toner or the like, the life of the developing roller is remarkably improved as compared with the case where urethane or the like is used. And
Examples of the fluorine-based elastomer include fluorosilicone rubber, fluorophosphazene rubber, vinylidene fluoride, hexafluoropropylene, hexafluoropropylene-tetrafluoroethylene-vinylidene fluoride copolymer, hexafluoroethylene-tetrafluoroethylene-vinylidene fluoride. Examples thereof include copolymers.

In the developing roller provided in the developing device according to the present invention and the manufacturing thereof, the developing roller surface (outer peripheral surface)
The resin layer provided in 1 is formed by using a coating composition containing the fluorine-based elastomer as a main component and a nitrogen-containing vinyl polymer in a range of 0.01 to 50 mass% k. Specifically, it can be formed by applying it on the surface of the developing roller substrate by a dipping method, a spray coating method, a roll coating method, or the like and drying it. In addition, the rolling thickness of the resin layer formed by coating and drying is 5% in order to secure sufficient mechanical strength.
It is at least μm, preferably at least about 30 μm.

[0017]

The coating composition according to the present invention contains a nitrogen-containing vinyl polymer as a resin component in addition to the organic binder (resin) which constitutes the main coating film forming component. Although its action is not always clear, gelation of the organic binder, which is the main component of the resin component, is effectively inhibited, and the storage stability after preparation is significantly improved. And, the gelation-inhibiting effect of this organic binder means the formation of a uniform and smooth surface coating film,
In combination with the fact that a protective film having a good exterior appearance can be formed, it can be said that this will contribute to further expansion of the application field of this type of coating composition.

For example, the fluorine-based elastomer has a smooth surface, so that the adhesion of toner on the surface of the developing roller can be easily prevented. That is, since the developing roller surface is in a state of easily maintaining cleanliness, it is possible to provide a stable image for a long period of time.

[0019]

【Example】

Example 1 First, a thermoplastic T-630 (trade name: Daikin Kagaku kk) as a fluorine-based elastomer (organic binder)
Manufactured), polyvinylpyrrolidone (nitrogen-containing vinyl polymer),
And methyl ethyl ketone (organic solvent) was prepared as a component. Next, each of these compositional components was weighed out in proportions (mass ratios) as shown in Table 1 to obtain 5 including the comparative example.
Various types of coating compositions were prepared. The coating composition should be prepared by dissolving the organic binder in an organic solvent while heating and holding it at 70 ° C, then adding a nitrogen-containing vinyl polymer and holding and dissolving at the temperature for 6 hours. Went by.

Table 1 also shows the properties (dissolved state) of the coating composition immediately after the preparation and the results of observation and evaluation such as the gel generation state when left at room temperature after the preparation.
In the case of Comparative Example b, a precipitate was recognized and the coating film formed was highly uneven, and the function as a paint was almost lost.

Table 1 Example Comparative Example A B C a b Organic binder 10 10 10 10 10 Organic solvent 120 120 120 120 120 Nitrogen-containing vinyl polymer 0.1 1 2 0 12 Dissolved state Good Good Good Good Precipitate Gelation Time (hr) 80 No gel formation after 1 month 10 − As can be seen from Table 1, the coating composition of Comparative Example a showed gelation after 10 hours of standing at room temperature, whereas the coating composition of Example A The composition showed gelation after 80 hours, and in the case of the coating compositions of Examples B and C, gelation did not occur even after 1 month, and in the case of each of Examples, the preservability was good. (Storability) is improved. In the above examples, urethane elastomer or polyamide elastomer was used instead of the fluorine-based elastomer (organic binder), and polyvinylcarbazole was used instead of polyvinylpyrrolidone.
The coating composition was prepared under the same conditions, and the properties (dissolved state) of the coating composition immediately after preparation and the state of gel generation when the composition was left at room temperature after preparation were also observed and evaluated.

Example 2 First, a thermoplastic T-630 (trade name: Daikin Kagaku kk) as a fluoroelastomer (organic binder)
Manufactured), polyvinylpyrrolidone (nitrogen-containing vinyl polymer),
Methyl ethyl ketone (organic solvent) and conductive carbon powder # 3050B (trade name: manufactured by Mitsubishi Kasei kk) were prepared as composition components. Next, each of these composition components was weighed in proportions (mass ratios) shown in Table 2 to prepare five types of coating compositions including comparative examples. The coating composition was prepared by dissolving the organic binder in an organic solvent while heating and holding at 70 ° C., adding a nitrogen-containing vinyl polymer, and holding and dissolving at the temperature for 6 hours. To room temperature, and at this point, conductive carbon powder was added and the mixture was dispersed in a homogenizer.

Table 2 also shows the properties (dissolved state) of the coating composition immediately after the preparation and the results of observation and evaluation such as the gel generation state when left at room temperature after the preparation.
In the case of Comparative Example d, a precipitate was recognized, and the coating film formed was highly uneven, and the function as a paint was almost lost.

Table 2 Examples Comparative Example D EF cd Organic binder 10 10 10 10 10 Organic solvent 120 120 120 120 120 Nitrogen-containing vinyl polymer 0.1 1 2 0 12 Conductive carbon powder 1 1 1 1 1 Dissolved Condition Good Good Good Good Precipitate Gelation time (hr) 701 No gel formation after 1 month 8--As can be seen from Table 1 above, gelation was observed after 8 hours at room temperature in the coating composition of Comparative Example c. On the other hand, the coating composition of Example D showed gelation after 70 hours, and the coating compositions of Examples E and F did not show gelation even after 1 month, In each of the examples, the preservability (storability) is improved. In the above examples, urethane elastomer or polyamide elastomer was used instead of the fluorine-based elastomer (organic binder), and polyvinylcarbazole was used instead of polyvinylpyrrolidone.
The coating composition was prepared under the same conditions, and the properties (dissolved state) of the coating composition immediately after preparation and the state of gel generation when the composition was left at room temperature after preparation were also observed and evaluated.

The present invention is not limited to the above embodiments, but various modifications can be made without departing from the spirit of the invention. For example, as the organic binder, a thermoplastic resin is used as one resin component in the examples, but the storage stability can be further improved even when a thermosetting resin such as an epoxy resin is used as one resin component.

Embodiment 3 This embodiment is for a developing device and will be described with reference to FIGS. 1 and 2.

FIG. 1 is a cross-sectional view showing the main structure of the developing device. 1 is a toner container, 2 is toner contained in the toner container 1, 3 is a toner agitator, and 4 is toner developing device. The toner supply roller supplies the roller 5. Reference numeral 6 denotes a toner layer regulating member whose tip end is pressed against the outer peripheral surface of the developing roller 5 by a spring 6a, and controls the toner layer carried on the outer peripheral surface of the developing roller 5 so as to control the latent image holding member (photosensitive drum). ) It is designed to supply 7 sides.
Further, 8 is a latent image holder 7 charged by a charger 9.
An exposure device for exposing a surface to form a desired electrostatic latent image, and 10 is a contact sheet with the developing roller 5 to form a toner image (development of the electrostatic latent image) on the surface of the latent image carrier 7 on a recording sheet. This is a cleaning unit that collects the residual toner remaining on the surface of the latent image holding member 7 after the transfer by the transfer device 11 to the above, and also contributes to cleaning of the surface of the latent image holding member 7. In FIG. 1, 12 is a recovery blade, 13 is a protective resistor, 14 is a DC power source, and the developing roller 5 and the toner supply roller 4 are connected via the protective resistor 13.
Bypass is applied between and. FIG. 2 is a perspective view showing the structure of the developing roller 5 included in the developing device. 5c is a stainless steel shaft, and 5b is concentrically arranged on the outer peripheral surface of the stainless steel shaft 5c. The urethane rubber layer 5a is a resin layer having a film thickness of 30 μm, which is mainly composed of a fluorine elastomer and is concentrically arranged on the outer peripheral surface of the urethane rubber layer 5b and contains a nitrogen-containing vinyl polymer. That is, this resin layer 5a was applied to the coating composition E exemplified in Example 2 by zipping the developing roller base body provided with the urethane rubber layer 5b and then applying it with a drier.
It was formed by drying for 20 minutes. The surface resistance of the developing roller 5 was 1 × 10 ⁵ Ω · cm.

Image development was carried out by setting the above developing device under the following conditions.

As the toner (developer) 2, 92 parts by weight of polyester resin, 4 parts by weight of carbon, 2 parts by weight of low molecular weight polypropylene, 2 parts by weight of metal-containing dye, 0.5 parts of silica as an external additive.
A non-magnetic one-component toner having a deposition average particle size of 10 μm composed of parts by weight was used. Further, the rotation of the latent image carrier (photosensitive drum) 7 is set to 50 mm / s, and the surface of the latent image carrier 7 is charged to a uniform surface potential (+500 V) by corona discharge from the charger 9. After that, after the image information is recorded (latent image formation) on the surface of the latent image holder 7 by the laser beam as the exposure device 8, the surface speed is changed.
The developing roller 5 rotated at 100 mm / s and applied with +200 V was pressed against the surface of the latent image holding member 7 for development. After transferring the developed toner image onto the recording paper by the transfer device 11,
Heat fixed.

In the image after the transfer, the line image was clear and the solid image was a uniform and high-density image. Also, 5
The 10,000 images after the life test were also clear images with no deterioration and maintaining the initial state. Furthermore, extremely good images were obtained even under high temperature and high humidity conditions.

[0031]

As described above, according to the coating composition of the present invention, even when the fluoroelastomer as the organic binder component is relatively difficult to dissolve in the organic solvent, precipitation or gelation occurs. Is suppressed or prevented, and storability is significantly improved. For example, it is possible to easily form a fluoroelastomer paint that has been difficult to use as a coating film because it has poor properties such as weather resistance and stain resistance but is hardly soluble in various organic solvents. Especially In other words, by improving the solubility of the coating composition according to the present invention, or improving / improving the storability of the solution, it becomes possible to form a practical protective coating film that more effectively utilizes the characteristics of the fluoroelastomer component.

Further, by using such a coating composition for forming the resin layer on the surface of the developing roller of the developing device, excellent weather resistance and stain resistance can be imparted to the developing roller.
It is possible to provide a developing device capable of forming a stable image for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration example of a main part of a developing device according to the present invention.

FIG. 2 is a perspective view showing a configuration example of a main part of a developing roller included in the developing device according to the present invention.

[Explanation of symbols]

5 ... Development roller 5a ... Resin layer 5b containing fluorine-based elastomer as a main component and containing nitrogen-containing vinyl polymer ... Urethane-based rubber layer 5c ... Stainless steel shaft

Front page continuation (72) Inventor, Yasushi Masatsugu Komukai Toshiba Town, Saiwai-ku, Kawasaki City, Kanagawa Prefecture, Toshiba Research & Development Center Co., Ltd. (56) Reference JP-A-6-282101 (JP, A) JP-A-4-204677 (JP, A) JP-A-60-151823 (JP, A) JP-A-58-68230 (JP , A) JP-A-7-72721 (JP, A) JP-A-1-108270 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 5/00-201/10 C08L 39/06 G03G 9/087 G06G 15/06 G03G 15/08

Claims (3)

(57) [Claims] 1. A fluorine-based elastomer as a main component, Po
A coating composition prepared a resin component and an organic solvent component as component comprising polyvinyl pyrrolidone, Poribinirupiro 0.01 to 50% by weight of the resin component
A coating composition characterized by being occupied by redone . 2. A developing device comprising a latent image holding member and a developing roller which is disposed so as to face the latent image holding member, wherein the surface of the developing roller base is made of a fluoroelastomer as a main component, and polyvinylpyrrolidone is used. 0.01 to 50% by mass
The developing device is characterized in that a resin layer is included in the range. 3. A latent image bearing member, in the manufacturing method of the developing apparatus comprising a developing roller which is disposed to face the latent image holding member, a fluorine-based Elastica on the developing roller substrate surface
Toma as the main component and polyvinylpyrrolidone 0.01
A method for producing a developing device, which comprises applying a coating composition containing a resin component and an organic solvent contained in an amount of ˜50% by mass, and drying the coating composition.