JP3145649B2 - Plastic filters for photo developing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic filter for a photographic developing device, and more particularly to a plastic filter for a photographic developing device for effectively separating and filtering foreign matter in each processing tank of the photographic developing device.

[0002]

2. Description of the Related Art An automatic developing apparatus for developing photographic photosensitive materials such as photographic film and photographic printing paper includes a processing tank in which a processing solution such as a developing solution, a fixing solution, and washing water is filled, and a processing tank disposed therein. It comprises transport means for sequentially passing the photographic light-sensitive material through each processing tank, a processing liquid circulation mechanism connected to each processing tank, a liquid temperature adjusting device disposed in the circulation mechanism, and the like.

The treatment liquid circulation mechanism includes a pipe and a solenoid valve for circulating each treatment liquid by a circulation pump, and removes various kinds of sludge, fine dust, scale, etc., generated by a chemical reaction. A filter for a photo developing device is interposed as a filtering means for removing.

A so-called sintering method is known in which a low-density or high-density polyolefin-based material such as polyethylene or polypropylene is filled in a mold, the mold is heated to a temperature near the melting point of the resin, and only the particle surface is fused. There is a plastic filter molded by the method.

However, in such a material, the elastic modulus sharply decreases at a temperature higher than the melting point, and a rubber-like flat portion is hardly observed. Interspaces are likely to be closed, and it is difficult to control porosity and pore diameter.

[Problems to be solved by the invention]

Accordingly, a commercially available plastic filter for a photographic developing apparatus is formed by sintering a material having a relatively large particle size. However, since this filter has a large pore diameter, it has a very small size inside a processing tank. There are problems that foreign matter cannot be separated and filtered, and that the production cost is high due to the batch-type molding method.

There is also a filter for a photographic developing device in which a nonwoven fabric or a thread-like fiber is wound around the outer periphery of a cylindrical plastic support in multiple layers. Therefore, there is a problem that foreign matter in the processing tank is increased.

[0008]

DISCLOSURE OF THE INVENTION As a result of intensive studies, the present invention has found a plastic filter for a photographic developing device having good filtration accuracy which can solve the above-mentioned problems. A porous filter obtained by sintering a plastic material, having a porosity of 30 to 60.
a plastic filter for a photographic developing device, characterized in that it has a filtration accuracy of not more than 30% by volume, and has a pressure loss of 20 mmAq or less at a dry air flow rate of 1 m ³ / m ² · min. , B) the thermoplastic material is ultra-high molecular weight polyethylene, and a plastic filter for a photo developing device having a hollow cylindrical body having a radial crushing strength of 5 kg / cm ² or more; and c) the average particle size of the ultra-high molecular weight polyethylene is 50 μm or more and 700 μm
The following is a plastic filter for a photo developing device.

A plastic filter for a photo developing device obtained by sintering and molding the thermoplastic material of the present invention has a porosity of 30 to 60% by volume, a filtration accuracy capable of collecting foreign substances of 30 μm or more, and a dry ventilation. 1m ³ /
It is necessary that the pressure loss at m ² · min be 20 mmAq or less. Preferably, the thermoplastic material is ultrahigh molecular weight polyethylene, and the radial crushing strength is 5 kg / cm ² or more, and more preferably, the average particle size of ultrahigh molecular weight polyethylene is 50 μm or more and 700 μm or more.
m or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic plastic material constituting the plastic filter for a photo developing device of the present invention includes polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride resins, polyester resins, and the like.
Among polyamide-based resins, polystyrene-based resins, polyacryl-based resins, fluorine-based resins, etc., there is no particular limitation as long as the material has a low melt flow rate (MFR) and can easily obtain a porous body. Absent. Among these, ultra-high molecular weight polyethylene having a particularly low melt flow rate (MFR) of 1.0 or less, preferably 0.01 or less, has a rubber-like flatness on a stress-strain curve in a wide temperature range of the melting point or higher. This is particularly suitable for obtaining a plastic filter for a photographic developing device having a uniform pore size, in which pores are not easily observed and pores between particles are hardly blocked.

The form of the thermoplastic material is preferably powdery, and the average particle size is 50 to 7
It may be within the range of 00 μm, preferably 60 to 50 μm.
0 μm gives good results. That is, when the average particle size is 50 μm or less, although the filtration accuracy is improved, the pressure loss at the time of passage of the fluid increases, which is not preferable. On the other hand, if the average particle size is 700 μm or more, satisfactory filtration accuracy cannot be exhibited, which is not preferable.

The porosity of the plastic filter for a photographic developing device of the present invention needs to be in the range of 30 to 60 vol%, and preferably 35 to 55 vol% gives good results. That is, the porosity is 30 vo
If it is 1% or less, the pressure loss at the time of passage of the fluid increases, which is not suitable for practical use. On the other hand, when the porosity is 60 vol% or more, the mechanical strength is insufficient, such as a decrease in radial crushing strength, which is not suitable for practical use.

In the present invention, the porosity is calculated by the following equation. Porosity (vol%) = [(A−B) / A] × 100 where A is the true density (g / cm ³ ) of the thermoplastic material constituting the plastic filter,
Is the apparent density of the plastic filter (g / cm ³ )
It is.

Here, the apparent density B of the plastic filter is obtained by measuring the mass and volume of a test piece cut from the filter by a conventional method, and calculating the mass value (g).
Divided by the volume value (cm ³ ).
The value of the volume can also be obtained by measuring the outer diameter, the inner diameter, and the length of the filter when the filter has a fixed shape, for example, a hollow cylindrical body, and calculating the volume.
On the other hand, the true density A of the thermoplastic material constituting the plastic filter can also be obtained by measuring a sample that has been cooled and solidified after re-melting the filter.

The filtering accuracy of the plastic filter for a photo-developing apparatus of the present invention needs to be such that foreign matters having a size of 30 μm or more can be collected. That is, the particle size of various foreign substances (various sludge, fine dust, scale, etc.) to be removed during the development processing is about 50 to 200 μm except for special foreign substances. On the other hand, the pore size of a filter obtained by sintering and molding a thermoplastic material has a certain distribution even when the shape and the particle size of the material particles are adjusted. In particular, if there is a portion having a large pore diameter, a large foreign matter that should be originally held on the filter surface and removed therethrough is passed, so that it is not practical. In other words,
It is necessary that the maximum diameter of the particles passing through the filter does not exceed 30 μm.

Whether or not the plastic filter has the required filtration accuracy is determined by filtering the air flow in which the calcium carbonate particles having different particle diameters float under a certain condition through the plastic filter. It can be known by measuring the maximum diameter of the particles. In the present invention, the filtration accuracy is indicated by the maximum diameter of the passing particles.

The conditions for this measurement are as follows. Calcium carbonate particles having a particle size of 1 to 600 μm are 25 g in air.
/ M ³ at a standard rate of 1 m ³ / m ² · air flow rate per unit area of the outer surface of the filter.
min.

The pressure loss of the plastic filter for a photographic developing device of the present invention is as follows: dry air flow rate 1 m ³ / m ² · m
It is necessary that the pressure loss at the time of in is 20 mmAq or less, and preferably 10 mmAq or less gives good results. When the pressure loss is 20 mmAq or more, the resistance to the fluid passing through the filter increases, so that it becomes difficult to feed the fluid at a high flow rate.

Whether the plastic filter is within the allowable pressure loss range depends on the pressure generated between the inner and outer surfaces of the filter when clean air containing no foreign matter is passed under certain conditions. It can be known by measuring the difference. In the present invention, the pressure loss indicates this pressure difference by the height of the water column (mmAq).

Further, the plastic filter for a photographic developing device of the present invention preferably has sufficient strength against compressive stress. The hollow cylindrical plastic filter preferably has a radial crushing strength of 5 kg / cm ² or more, more preferably 10 kg / cm ² or more. If the radial crushing strength is 5 kg / cm ² or less, there is a possibility that problems such as breakage and breakage during handling may occur.

Thus, in the present invention, the radial crushing strength is:
It is calculated by the following equation. Radial crushing strength (kg / cm ² ) = P (Dt) / (L ×
t ² ) where P is the breaking load (kg), D is the outer diameter of the filter (cm), and t is the thickness of the filter (cm).
And L is the length (cm) of the filter.

Here, the breaking load P is a value (kg) of the maximum load until the test piece is broken by compression. The test piece was 1 cm in length, and a compressive load was applied at a constant speed in a direction perpendicular to the central axis of the test piece cylinder.

The method of sintering and molding the plastic filter for a photo-developing apparatus of the present invention is not particularly limited, and is usually a so-called in-mold sintering method. That is, using a molding die consisting of an outer mold having an inner surface shape such as a cylindrical shape and an inner mold having a similar outer surface shape inserted therein, the gap between the inner surface of the outer mold and the outer surface of the inner mold is used. After filling the formed cavity with the thermoplastic material, the molding die and the molding die are heated together. In addition to the static molding method, (1) reciprocating in a temperature-adjustable cylinder having a molding die at the tip end A ram extrusion method using a ram type extruder with a built-in moving piston (also called a plunger), (2) an injection molding machine with a molding die at the tip and a screw inside a temperature-adjustable cylinder. And (3) a dynamic molding method such as an extrusion molding method using an extruder having a screw inside a temperature-adjustable cylinder having a molding die at the tip.

From the methods such as the static molding method and the dynamic molding method, the shape of the final porous body and the like may be appropriately selected according to requirements. However, in terms of manufacturing cost and production efficiency, the ram extrusion method using a ram extruder with a built-in piston in the cylinder and the extrusion molding method using an extruder with a screw built in the cylinder are continuous. It is preferable because a plastic filter can be molded.

[0025]

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

In the following Examples and Comparative Examples, various characteristics and performance tests of the plastic filter for a photographic developing device were measured or evaluated according to the following methods, and the results were displayed.

(1) Porosity The true density of the constituent plastic material is A (g / cm ³ ), and the apparent density of the plastic filter is B (g / cm ³ ).
^{As 3} ), determine the porosity by the following equation. Porosity (vol%) = [(AB) / A] × 100 Therefore, the volume is about 20 cm more than the plastic filter.
The test piece of No. ³ is taken, and the weight of the test piece is measured using a weighing device, and the apparent density B is obtained by the following equation. Apparent density B = mass of test piece (g) / volume of test piece (c)
m ³ )

(2) Filtration accuracy One of them is a particle-containing air chamber containing calcium carbonate particles,
Inside the other container, which is a separate air chamber communicating with a vacuum pump, inner diameter: 17.0 mm, outer diameter: 24.0 mm, length:
A plastic filter of a 143 mm hollow cylindrical body is sealed with one opening, and the other opening is arranged and locked in a separation air chamber. Into the particle-containing air chamber, air in which 25 g / m ^{3 of} calcium carbonate particles having a particle diameter of 1 to 600 μm is sent, and the air in the container is evacuated by a vacuum pump to 1 m ³ / m ² · min (at a temperature of 23 ° C., (Pressure 1 atm). At that time, calcium carbonate particles in the separation air chamber that passed inside from the outer surface of the filter were collected,
The maximum particle diameter is measured, and the result is taken as the filtration accuracy.

(3) Pressure loss A plastic filter having a hollow cylindrical body is provided with a manometer attached to one opening of the hollow cylindrical body, and a vacuum pump attached to the other opening. Predetermined flow rate per 1 m ² ) (1 m ³ / min: temperature 2)
Suction is performed so as to form air at 3 ° C. and a pressure of 1 atm. The pressure difference at that time is measured, and the pressure difference is defined as a pressure loss (mmAq).

(4) Radial Ring Strength A test piece having a length of 1 cm was taken from a hollow cylindrical plastic filter, and this test piece was sandwiched between two flat plates using a compression tester. At right angles to
The specimen is compressed at a speed of 2 mm / min, the breaking load of the test piece is measured, and the radial crushing strength is determined by the following equation. Radial crushing strength (kg / cm ² ) = P (Dt) / (L ×
t ² ) P: Breaking load (kg) D: Filter outer diameter (cm) t: Filter wall thickness (cm) L: Filter length (cm)

(5) Performance test A plastic filter was attached to each processing tank of the automatic developing apparatus, and the apparatus was actually operated for two weeks. The state of liquid contamination in the tank, the state of foreign matter collection on the filter surface, the filter The evaluation was performed by observing the fluctuation state of the amount of the passing treatment liquid. In the display of the results, 場合 indicates that there was no abnormality, and X indicates that there was abnormality.

[0032]

Example 1 An average particle size of 400 μm and an MFR of 0.01
Hereinafter, ultra-high molecular weight polyethylene having a molecular weight of 6,000,000 is extruded with a ram extruder provided with a die having a cylindrical opening such that the outer diameter of the plastic filter is 24.0 mm and the inner diameter is 17.0 mm at the tip, The melt-dispersed particles were mutually fused with the die to obtain a plastic filter for a photographic developing device.

[0033]

Example 2 An average particle size of 400 μm and an MFR of 0.01
An ultra-high molecular weight polyethylene having a molecular weight of 6,000,000 and a bi-directional conical extruder having a plastic filter having a cylindrical opening at its tip having an outer diameter of 24.0 mm and an inner diameter of 17.0 mm are provided. And the melt-dispersed particles were mutually fused with the die to obtain a plastic filter for a photo developing device.

[0034]

Example 3 An average particle size of 160 μm and an MFR of 0.01
An ultra-high molecular weight polyethylene having a molecular weight of 6,000,000 and a bi-directional conical extruder having a plastic filter having a cylindrical opening at its tip having an outer diameter of 24.0 mm and an inner diameter of 17.0 mm are provided. And the melt-dispersed particles were mutually fused with the die to obtain a plastic filter for a photo developing device.

[0035]

Comparative Example 1 As a molding die, one inner mold having a cylindrical outer surface and one outer mold having a cylindrical inner surface are prepared. The outer diameter of the inner mold is 7 mm smaller than the inner diameter of the outer mold. First, the inner die is inserted into the outer die, and the inner die is set so that a gap of 3.5 mm is uniformly formed between the outer die and the inner die. Next, in the gap, the average particle size is 800 μm.
Then, ultra-high molecular weight polyethylene having a MFR of 0.01 or less and a molecular weight of 4,000,000 is filled, and this is heat-sintered and molded in a heating furnace at a temperature of 160 to 200 ° C. for 30 minutes to have an outer diameter of 24.0 m.
m and an inner diameter of 17.0 mm were obtained.

[0036]

Comparative Example 2 Using the same molding die as in Comparative Example 1, the average particle size was 30 μm in the gap of 3.5 mm between the outer mold and the inner mold.
Then, ultra-high molecular weight polyethylene having a MFR of 0.01 or less and a molecular weight of 4,000,000 is filled, and this is heat-sintered and molded in a heating furnace at a temperature of 160 to 200 ° C. for 30 minutes to have an outer diameter of 24.0 m.
m and an inner diameter of 17.0 mm were obtained.

[0037]

Comparative Example 3 Using the same molding die as in Comparative Example 1, an average particle size of 1,000 was set in a gap of 3.5 mm between the outer die and the inner die.
0 μm, low-density polyethylene having a MFR of 6.0 and a molecular weight of 50,000 was filled in a heating furnace at a temperature of 160 ° C. for 30 minutes.
Minute heat sintering molding, outer diameter 24.0mm, inner diameter 17.
A 0 mm plastic filter for a photo developing device was obtained.

[0038]

Comparative Example 4 Using the same molding die as in Comparative Example 1, the average particle size was 100 μm in the gap of 3.5 mm between the outer mold and the inner mold.
m, low-density polyethylene having a MFR of 10.0 and a molecular weight of 40,000 was filled, and this was heat-sintered and molded in a heating furnace at a temperature of 160 ° C. for 30 minutes. .

[0039]

[Table 1]

As shown in Table 1, in the plastic filters of Examples 1 to 3, the filtration accuracy was 30 μm or less, and even in an actual performance test, foreign substances were efficiently collected on the surface of the filter. The liquid in the processing tank was kept clean. Also, no decrease in the amount of the processing liquid passing through the filter was observed, and the plastic filters of Examples 1 to 3 maintained a sufficiently low pressure loss of 20 mmAq or less.

However, in the plastic filters of Comparative Examples 1 and 3, the filtration accuracy was 80 μm and 100 μm, the foreign matter in the processing tank was not completely collected, and 100 cc of the liquid in the processing tank was visually observed. Considerable foreign matter was floating. In addition, the plastic filter of Comparative Example 2 had a high pressure loss, so the circulation of the processing liquid in the tank was poor, and the amount of the processing liquid passing through the filter was reduced. As a result, the temperature in the processing tank increased. Trouble was found. Further, in Comparative Example 4, the pores between the particles were closed in the mold during sinter molding, and the porous body was not obtained.

[0042]

As described above, the plastic filter for a photographic developing device of the present invention has a porosity of 30 to 60 v.
ol%, has a filtration accuracy capable of collecting foreign substances of 30 μm or more, and has a pressure loss of 20 mmAq or less at a dry air flow rate of 1 m ³ / m ² · min. Since it has high accuracy and can efficiently separate and filter foreign matters in the processing tank, it is useful as a filter for a photo developing device.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-309125 (JP, A) JP-A-2-212132 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 39/16 G03D 13/00

Claims (3)

(57) [Claims] 1. A plastic filter for a photo-developing apparatus formed by sintering and molding a thermoplastic material, having a porosity of 30 to 60 vol%, a filtration accuracy capable of collecting foreign substances of 30 μm or more, and a dry type filter. Ventilation rate 1m ³ / m
^A plastic filter for a photo developing device, wherein a pressure loss at ² min is 20 mmAq or less. 2. The plastic filter according to claim 1, wherein the thermoplastic material is an ultra-high molecular weight polyethylene and has a hollow cylinder having a radial crushing strength of 5 kg / cm ² or more. 3. An ultrahigh molecular weight polyethylene having an average particle size of 5
3. The plastic filter for an automatic developing device according to claim 2, which has a thickness of 0 to 700 [mu] m.