JPH0636122B2 - Filter for copying machine cleaning roll - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dust collecting filter. In particular, it relates to a filter attached to a cleaning roll of a copying machine.

<Prior Art> Generally, the function of a cleaning roll of a copying machine mainly has the following two points.

(1) Removal of toner remaining on the heating / pressurizing roll of the copying machine (roll cleaning) (2) Application of a leveling agent (for example, silicon-based smoothing agent) to the heating / pressurizing roll of the copying machine. The characteristics required of the cleaning roll for use are as follows.

(1) To remove the toner remaining on the cleaning roll (cleanability) (2) A small amount of a smoothing agent can be evenly applied to the surface of the cleaning roll (uniform coating property) (3) The operating temperature during copying Can withstand a long period of time (heat resistance and durability) (4) Abrasion resistance (5) Friction resistance (6) Oil absorption The cleaning roll conventionally used to satisfy these required characteristics is made of hollow aluminum. A metal pipe coated with felt made of heat-resistant fluorine-based fiber or wholly aromatic polyamide-based fiber is used. The smoothing agent is applied to the cleaning roll by injecting a small amount of the smoothing agent into a part of the felt and using diffusion, or by injecting the smoothing agent into the hollow part of the metal pipe and then through the holes provided in the pipe. Spread the smoothing agent on the surface. The uniform diffusion of the smoothing agent is carried out during the heat and pressure rotation of the cleaning roll. The heat pressure rotation may be performed at a high temperature of 160 to 220 ° C. Further, a cleaning roll coated with a film-like material is used instead of the felt, but the removability of the residual unnecessary toner and the uniform coating property of the smoothing agent are not good.
In addition, felt made of short fibers is used. For example, a felt made of fluorine-based fiber is used. Although it is excellent in surface smoothness, abrasion resistance, abrasion resistance, heat resistance, etc., it has a strong water repellency and oil repellency, and therefore has a poor effect of removing unnecessary toner remaining on the cleaning roll. Also, for the same reason, the diffusion of the smoothing agent between the short fibers constituting the felt is not good. Furthermore, the felt made of wholly aromatic polyamide fiber has many excellent points such as abrasion resistance, abrasion resistance, heat resistance, oil absorption, and removability of unnecessary residual toner. The uniform application property of the agent is insufficient. Further, it is still not sufficient in terms of eliminating the fiber fluff on the surface of the cleaning roll (felt surface) and maintaining the uniformity (smoothness) of the contact surface.

Also, as a cleaning roll that collects residual unnecessary toner by using electric charging, "electret such as perfluoroalkoxy or fluoroethylene propylene has been electret-treated with corona irradiation, ion beam irradiation, etc. A dust collecting filter for a second dust collecting device of a cleaning device of a copying machine, characterized in that the fibers are formed into a cotton shape "
(Japanese Patent Laid-Open No. 59-228277) is disclosed, but in this case, the electret property imparted to the fiber is halved by injecting and diffusing the smoothing agent into the cleaning filter, and However, its sustainability is lost and sufficient effects cannot be expressed, and the intended purpose cannot be achieved.

The present invention has been earnestly studied under such a background, and an object thereof is to solve the above-mentioned problems, that is, to reduce monofilament fluff that is scattered on the filter surface and improve surface smoothness. That is, the diffusibility of the smoothing agent is made good to improve the uniform coating property, and the performance (cleaning durability) capable of continuously removing the unnecessary residual toner adhering to the surface of the cleaning roll is provided.

<Structure of Invention> The present invention has been made to solve the above problems. That is, the present invention is a "filter for a copying machine cleaning roll characterized in that an aramid resin film is scattered on the surface of a fiber structure and has an air permeability of 3 to 25 cc / cm ² / sec". Here, the fibrous structure is a woven or knitted fabric, a non-woven fabric, a net-like product, or a laminated body formed by combining these. An aramid resin is an aramid resin that is soluble in at least 1% by weight or more in a solvent, and is polymetaphenylene isophthalamide, polyparaphenylene terephthalamide, wholly aromatic polyamideimide, aromatic diamine / aromatic dicarboxylic acid chloride / aliphatic. Diamine / aliphatic dicarboxylic acid chloride copolymer or the following repeating unit (1)
To (3) aromatic polyamide [Wherein Ar ₁ and Ar ₂ may be the same or different, and the aromatic carbocyclic residue having the bonding chains extending in the coaxial direction or the parallel axis direction, Ar ₃ and Ar ₄ may be the same or different. , A paraphenylene group and a metaphenylene group. R _{1 to} R ₄ may be the same or different and each represents an alkyl group having 5 or less carbon atoms and a hydrogen atom. ] As a solvent capable of dissolving at least 1% by weight of wholly aromatic polyamide, for example, N-methyl-2-pyrrolidone, N,
Examples thereof include N-dimethylformaldehyde, N, N-dimethylacetamide, hexamethylphosphoramide, tetramethylurea, N-methyl-caprolactam and N-methyl-piperidine.

To disperse the aramid resin coating on the surface of the fiber structure, for example, the following is performed. First, a wholly aromatic polyamide resin is dissolved in any of the above solvents, and further a known water repellent, a plasticizer, a stabilizer, a softening agent, and the like are mixed in an appropriate amount as necessary to prepare a blended solution (dope), After impregnating or coating each part or the whole of the fiber structure with the dope, it is dry-coagulated or wet-coagulated to disperse the aramid resin coating on the surface of the fiber structure.

The air permeability of the fiber structure having the aramid resin coating scattered on the surface is in the range of ^{3 to} 25 cc / cm ² / sec. Breathability is 3
If it is less than cc / cm ² / sec, the performance (cleaning property) for removing the residual toner adhering to the cleaning roll is insufficient and not practical. If the air permeability exceeds 25 cc / cm ² / sec, it will be difficult to evenly disperse the smoothed material when the smoothing agent is applied to the treated fiber structure (felt, for example).

The fiber structure can be coated with the aramid resin by coating using a known method, for example, a coating machine such as a knife coater, a reverse roll coater or a gravure coater. Also in the case of coating by impregnation, a known method such as a dipping method or a spray method is used.
In this way, the fiber structure impregnated with the aramid dope is immediately immersed in water or a mixed solution consisting of a solvent miscible with water to coagulate the aramid resin, and if necessary, a vacuum dehydrator, Preliminary dehydration is performed using a nip roll or the like, and then dried using a chute dryer, a non-touch dryer, a tenter or the like.

In the case of the dry coagulation method, the same type of explosion-proof dryer as described above is used, and the temperature is relatively low, for example, from 50 to 60 ° C. to a high temperature region where the used fiber material is not thermally deteriorated, for example, from 150 to 200 ° C. gradually. It is desirable to carry out a temperature rising heat treatment and dry. When the impregnated or coated fiber structure is heat-treated from the beginning at a high temperature, the solvent evaporates rapidly and it is difficult to form a uniform film.Therefore, the drying temperature is appropriately set within 30 to 30 seconds within the divided temperature range of 50 to 200 ° C. It is preferable that the resin is coagulated by allowing the solvent to evaporate by allowing the resin to pass through for about 30 mm. The fiber structure coated with the aramid resin can be cut to an appropriate size as it is, and then wound around the pipe for rolls to be used, but in order to obtain better characteristics, it is further subjected to a heat and pressure treatment. Then, it is desirable to improve the adhesiveness and adhesion between the constituent fibers of the fibrous structure and the coating formed on the surface thereof, and to impart surface smoothness and flexibility.

Also, for the purpose of streamlining the process, etc., first, a woven or knitted fabric composed of felt-like structures or short fibers is cut into an appropriate size, which is previously wound into a single layer or multiple layers to form a hollow pipe. And a mixed solution (dope) prepared by the same method as described above, that is, a wholly aromatic polyamide-based resin in at least 1 part thereof.
Wet or dry coagulation after impregnating or coating a solution (dope) dissolved in a solvent of not less than wt% to form an aramid resin coating on the surface of the pipe-shaped fiber structure and reduce surface fluff as much as possible May be smoothed. In this case, the surface fluff, the air permeability and the diffusivity of the smoothing agent can be controlled by adjusting the viscosity of the dope to be used, the impregnation time and the coating amount. Usually, the air permeability is preferably 3 to 25 cc / cm ² / It is preferable to control to sec. Also,
Furthermore, after the pipe-shaped fiber structure is inserted into an iron core or the like, the surface of the pipe-shaped fiber structure is heated and pressure-treated to form an adhesive property between the aramid resin coating film and the constituent fibers formed on the surface of the pipe-shaped fiber structure. The adhesion and the smoothness and the air permeability may be controlled at the same time. The heating and pressurizing conditions at this time are such that the heating roll temperature is about 160 to 350 ° C. and the linear pressure is 1 to 35 kg / cm depending on the processing speed, purpose of use, and various necessary characteristics. The heating and pressurizing means is usually carried out by passing the pipe-shaped fiber structure through an iron core or the like, then pressing it against a heating roll and rotating it. However, the heating and pressurizing means is not limited to this method, and any means can achieve the original purpose. The method may be used, for example, a method in which the pipe-shaped fiber structure is passed through an iron core or the like by a hot plate press and then sandwiched and rolled. This heat treatment process partially softens the aramid-based resin to increase the degree of adhesion with the fiber structure, and at the same time, the fiber structure itself is thermally and thermally set when it is at a high temperature, and has excellent heat stability. Further, heat durability, surface smoothness, and flexibility are imparted, and heat resistance and ventilation stability are improved, so that a suitable fiber structure can be obtained by a cleaning roll for a copying machine. Further, when it is necessary to further increase the stability to heat, curing may be performed at a temperature and for a time within a range that does not impair various properties of the fiber structure.

As described above, the cleaning filter for a copying machine of the present invention is wet-coagulated or impregnated with the aramid resin dope after impregnating or coating the fiber structure, or after impregnating or coating the fiber structure formed into a pipe shape. It is completed by forming an aramid resin coating on the surface of the fiber structure by dry coagulation. The resulting cleaning roll filter for a copying machine of the present invention (a polymethaphenylene isophthalamide resin dispersed in a felt-like material;
Example 2, which is scattered on a woven fabric; Example 5) and a surface enlarged plan view of a filter (Comparative Example 1) in which no resin is scattered are shown as FIGS. 1, 2 and 3.

<Effects of the Invention> The cleaning roll filter of the present invention has abrasion resistance,
It has abrasion resistance, oil absorption, chemical resistance, etc., but has the following effects.

(1) High performance of removing the residual toner adhering to the cleaning roll (cleaning property) (2) The cleaning roll surface can be uniformly coated with a small amount of smoothing agent (uniform coating property) (3) High heat-resistant dimensional stability <Examples> Next, the present invention will be described based on Examples. The method for evaluating the characteristics of the product of the present invention is as follows.

1) Cleaning action (removal of residual unnecessary toner) A mirror-finished flat plate (30 cm x 40 cm) is placed horizontally, and about 8 to 10 g of toner liquid for a copying machine is dropped on it and applied by brush, and then the product of the present invention is applied. The product cut into 20 cm x 1 cm was placed on the flat plate, and a flat plate with a constant load (load: 6 g / cm ² ) of the same size as the sample was placed on the flat plate and then moved horizontally at a constant speed to remove the toner liquid. The state on the mirror flat plate after removing is visually judged. The judgment is as follows.

(1) When the whole is uniformly removed → ○ (2) When a small amount of toner remains on a part of the plate → △ (3) Toner liquid remains in spots or lines on the plate in some places → × 2) Ventilation characteristics Measure according to JIS L-1079.

The test used a Frazier type breathability tester.

3) Diffusivity of smoothing agent (coating property) Measure according to JIS L-1079A method.

However, liquid silicone leveling agent is used instead of water.

4) Heat stability Stability is judged by the air permeability and the rate of change of thickness after heat-treating the material at 200 ° C for 24 hours. Either or both of the characteristics (1) Change rate of less than 15% compared to before heat treatment → ○ (2) Change rate of 15% to less than 40% compared to before heat treatment → △ (3 ) A rate of change of 40% or more compared to before heat treatment → × 5) Thickness Measure according to JIS L-1079.

A compression elasticity tester (Maeda type) was used as the tester.

Examples 1 and 2, Comparative Example 1 Polymetaphenylene isophthalamide was dissolved in NN-dimethylacetamide, and the solution concentration was adjusted to 15% by weight (solid content ratio).

On the other hand, a felt-like material having a basis weight of about 450 g / m ² was prepared using aramid-based fibers, and the fiber structure was impregnated with the aramid-based resin dope by a pad method and then about 20 to 150 kg / cm with a nip roll. After squeezing under the linear pressure of, and adjusting the pickup amount to about 60 to 120% by weight,
Approximately 0.5 to 1 in hot air atmosphere classified into ℃, 150 ℃, 170 ℃
It was dried for 0 minutes and semi-finished. In Example 2, immediately after the pickup amount was adjusted, the sample was immersed in running water for about 5 to 20 minutes,
Wet solidified, then about 20-150Kg / cm with nip roll
After squeezing under the linear pressure of 130 ° C to 170 ° C in a hot air atmosphere until it is completely dried, the temperature is further 240 ° C with a calender roll, the clearance is 0.5 to 0.8 mm, and 150
A semi-finished product was obtained by heating and pressing under a linear pressure of Kg / cm. Table 1 shows the results obtained by measuring the obtained finished product (semi-finished product) by the above-mentioned evaluation method. In fact, this semi-finished product has an appropriate width,
Cut it into lengths and wind it on a perforated hollow iron pipe,
Commercialized as a roll for copiers.

For reference, the results of evaluation of the same felt before impregnation with the aramid resin dope are shown in Table 1 as Comparative Example 1. From Table 1, it is clear that the product of the present invention has improved cleaning action and heat resistance stability while maintaining proper air permeability and diffusibility of the smoothing agent.

Example 3 and Comparative Example 1 Example 3 was prepared in the same manner as in Example 1 using a knife coater on one side of the same felt-like material as in Example 1, and the solution concentration was 20% by weight (solid content ratio). After applying the aramid resin dope adjusted to about 60 g / m ² in terms of solid content, 130
Approximately 0.5 to 1 in hot air atmosphere classified into ℃, 150 ℃, 170 ℃
It was dried for 0 minutes. Thereafter, a calender roll was used to heat and pressurize at a temperature of 280 ° C., a clearance of 0.5 to 0.8 mm, and a linear pressure of 100 Kg / cm to make a semi-finished product. Table 1 shows the measurement results of the obtained semi-finished products by the above-mentioned evaluation method.

For reference, the evaluation results of the same felt before coating with the aramid resin dope are shown in Table 1 as Comparative Example 1. From Table 1, the product of the present invention has an appropriate breathability,
It is apparent that other properties are improved while maintaining the smoothing agent diffusibility.

Example 4, Comparative Example 2 In Example 4, the felt-like material composed of polyester short fibers was impregnated with the aramid resin dope used in Example 1 by the pad method, and then the nip roll was used for about 20 to 15
Squeezing under a linear pressure of 0 kg / cm, the pickup amount is about 60 to 120
Immediately after adjusting to wt%, soak in running water for about 5 to 20 minutes, wet solidify, then about 10 to 150 Kg with nip rolls
Table 1 shows the results of measurement by the above-described evaluation method for the coating completed by drying completely in a hot air atmosphere set at 130 to 160 ° C. under a linear pressure of / cm. It is clear that various properties of the product of the present invention are improved as compared with Comparative Example 3 before being treated with the aramid resin dope.

Example 5 and Comparative Example 3 Example 5 is a woven fabric composed of aramid short fibers and having a basis weight of about 300 g / m ² . A hollow metal pipe (pipe for cleaning roll of copier) having small holes in the direction perpendicular to the length direction is cut into a suitable size so that the woven cloth has two layers in a spiral shape. And after winding so that the surface after winding is as flat as possible, it was dipped in the aramid resin dope used in Example 1 and then this was pressed between the upper and lower two plates. After rolling with a pinch to adjust the pickup amount to about 50 to 65% by weight, it was dried for about 0.5 to 10 minutes in a hot air atmosphere divided into temperatures of 130 ° C, 150 ° C, and 170 ° C. Further, this was rolled by sandwiching it between two plates, which were heated and pressurized at 240 ° C and 2 Kg / cm, and the surface was smoothed. The measured results are shown in Table 1. The physical properties were measured by cutting the coating and removing the pipe-shaped metal core.

For comparison, resin treatment and woven fabric before processing,
The results of the same evaluation are shown in Table 1 as Comparative Example 1. It can be seen from Table 1 that the product of the present invention is superior in respect of various other properties required as a cleaning roll for a copying machine while maintaining appropriate ventilation properties and smoothing agent diffusibility.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged plan view of the surface of the present invention (Example 2), and FIG. 2 is an enlarged plan view of the surface of another embodiment (Example 5) of the present invention. FIG. 4 is an enlarged plan view of the surface of a filter (Comparative Example 1) in which an aramid resin is not scattered and coated. 1 is a fiber, 2 is an aramid resin coating, 3 is a warp, and 4 is a weft.

Claims (1)

[Claims] 1. A filter for a copying machine cleaning roll, characterized in that an aramid resin coating is scattered on the surface of a fiber structure and has an air permeability of 3 to 25 cc / cm ² / sec.