JPH06324461A - Liquid level sensor - Google Patents

Abstract

PURPOSE:To provide the liquid level sensor of an electrode type which prevents the penetration of liquid and prevents an operation defect. CONSTITUTION:A detecting section 84 of the liquid level sensor 82 is tightly adhered and coated by a coating member 100 which is inserted with a pair of electrodes 86A, 86B and is molded with a thermoplastic resin having high thermal shrinkability so as to expose an electrode part 88 and is held by a stabilizer part 102 so as to prevent the deviation in relative positions by variations of the electrodes 86 from each other. This detecting part 84 is formed by inserting this coating member 100 therein and molding an elastic member 104. The coating member 100 is adhered by welding to the elastic member 1 04 at the time of molding and is mounted by fitting the groove part 106 of the elastic member 04 to the peripheral edge of a through-hole 92 in a side plate 16A. The electrodes 86 and the coating member 100 are tightly adhered and, therefore, even if the developer adheres to the electrode part 88, the developer does not penetrate the inside of the detecting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level sensor for detecting a liquid level in a processing tank of a photosensitive material processing apparatus.

[0002]

2. Description of the Related Art A photosensitive material on which an image has been exposed is successively dipped in a processing solution such as a developing solution, a fixing solution, and washing water by a photosensitive material processing apparatus to be processed, and then dried.
In the photosensitive material processing device, a certain amount of developing solution, fixing solution, washing water, etc. for processing the photosensitive material is stored in each processing tank, and the photosensitive material is conveyed while being dipped in each processing solution in order. I am trying to do it.

In the processing tank for storing the processing solution, the photosensitive material is processed and the processing solution is replenished over time, and the excess fatigued processing solution is overflowed and discharged. The photosensitive material is processed at the level of the overflowing liquid surface. Some photosensitive material processing devices are provided with a liquid level sensor in the processing tank.
For example, when the processing liquid decreases due to evaporation or the like, the liquid level sensor detects the liquid level of the processing liquid, and when the liquid level falls below a predetermined level, the processing liquid is replenished or an alarm is issued. The operator is notified by. As a result, in the photosensitive material processing apparatus, it is possible to store a processing solution having a constant amount and a constant processing performance in each processing tank and process the photosensitive material with a constant quality.

By the way, as a liquid level sensor for detecting the liquid level of the processing liquid, there is an electrode type liquid level sensor formed by inserting a pair of electrodes of a detecting portion into an elastic member and molding. In such a liquid level sensor, the liquid level is detected by the tips of the pair of electrodes of the detection unit. By molding the detection unit with an elastic material, the elastic material is elastically applied to the through hole provided at the predetermined position. Since it can be deformed and attached, it is extremely easy to attach and adjust.

[0005]

However, when a pair of electrodes is inserted into an elastic material such as an elastomer and molded, the peripheral surface of the electrode and the elastic material may be separated with time to form a gap. . The treatment liquid adhering to the electrodes permeates into the gap due to surface tension or the like. The processing liquid that permeates between the electrodes and the elastic material is connected between the stabilizer for fixing the pair of electrodes and the elastic material, and the energization state between the pair of electrodes is changed to accurately detect the liquid level. Can not do.

Further, the processing solution soaked adheres to and deposits on the wiring for energizing the electrodes to corrode the core wire,
Further, the wiring may be attached to an electrical component for detecting the liquid level, which may cause a malfunction of the liquid level detection device.

The present invention has been made in consideration of the above facts, and it is an object of the present invention to provide a liquid level sensor capable of preventing a malfunction due to liquid soaking and accurately detecting a predetermined liquid level. To aim.

[0008]

A liquid level sensor according to claim 1 of the present invention is capable of detecting whether or not the tips of a pair of electrodes constituting a detection portion are in contact with a liquid. In addition, the periphery of the connection portion between the pair of electrodes of the detection unit and the wiring electrically connected to these electrodes is individually insert-molded with a first resin, and these electrodes are further arranged in a predetermined positional relationship. The molded portion formed of the first resin is insert-molded with the second resin having elasticity in a state of being held at.

A liquid level sensor according to a second aspect of the present invention is the liquid level sensor according to the first aspect, wherein the first resin is a resin having a large heat shrinkability.

[0010]

In the liquid level sensor according to claim 1 of the present invention, the first resin is insert-formed around the connecting portion between the pair of electrodes and the wiring, and the insert molding portion made of the first resin is further formed. The detector is formed by insert molding with a second resin having elasticity so as to cover it. Since the detection portion has elasticity at the outermost peripheral portion, it is possible to insert the resin molding portion having elasticity into the attachment through hole or the like provided at a predetermined position while elastically deforming and attaching the resin molding portion.

Even if the liquid permeates between the first resin and the pair of electrodes, since the pair of electrodes are individually insert-molded in the resin, even if the liquid adhering to one electrode permeates the other. Never reach the electrode.

By molding the second resin having elasticity so as to cover the first resin molding portion, both resins are mixed at the boundary in a state where the first resin and the second resin are heat-welded at the time of molding. Since the joint printing is performed as described above, the first resin and the second resin can be firmly bonded. A thermoplastic resin is preferably applied as the first resin.

In the liquid level sensor according to the second aspect of the present invention, the first resin is a resin having a large heat shrinkability. Therefore, after inserting and molding the electrodes, the first
When the resin is cooled, it is heat-shrinked and tightly adheres to the periphery of the electrode, a gap can be eliminated between the electrode and the first resin, and the first resin peels off from the electrode over time. Can be prevented. As a result, it is possible to reliably prevent the liquid from seeping between the electrode and the first resin.

As described above, since it is possible to prevent the conductive liquid from soaking into the detecting portion, it is possible to prevent malfunction due to the liquid soaking in. Further, since the liquid does not adhere to and is deposited on the electrical component that detects the energization state between the pair of electrodes through the wiring or the like, malfunction of the liquid level sensor can be prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an automatic developing apparatus 10 which is a photosensitive material processing apparatus to which the present invention is applied. The automatic developing apparatus 10 is a device in which a film 12, which is an example of a light-sensitive material, is dipped in a developing solution, a fixing solution and washing water to be processed, and then dried.

The automatic developing device 10 includes a developing section 18 having a developing tank 16 in a machine frame 14 and a fixing section 2 having a fixing tank 20.
2. A rinsing unit 26 including the rinsing tank 24, a rinsing unit 30 including a rinsing tank 28, and a drying unit 68 are provided.

Transport racks 38, 40, 42 having a plurality of roller pairs 32, 34, 36 (in the case of the water washing tank 28, roller pairs 32, 36) in the developing tank 16, the fixing tank 20, and the water washing tank 28, respectively. Are soaked in a developing solution, a fixing solution, and washing water.

In the roller pairs 32 and 34, the line connecting the axes of the rollers facing each other is horizontal, and the roller pair 36 is
The line connecting the axes of the rollers facing each other is vertical, and the film 12 is sandwiched by these and transported to form a substantially U-shaped transport path.

Here, each processing tank (developing tank 16, fixing tank 2)
0, the washing tank 28) is narrowed slightly below the liquid level (the liquid level shown by the imaginary line in FIG. 1) when a predetermined amount of treatment liquid is stored, and the horizontal cut surface is oriented upward. A stepped portion 44 is formed. Correspondingly, the transport racks 38, 40, 42 have a stepped portion 46 having a narrow width at the front end portion (below the central portion in the height direction) immersed in the processing liquid and a downward horizontal cutting surface. Are formed. For this reason,
The transport racks 38, 40, 42 are configured to be positioned and held by the step portion 46 being supported by the step portion 44 of the processing tank.

The transport rack 38 of the developing tank 16 is provided with a pair of rollers 50 facing the insertion port 48, and holds and conveys the film 12 inserted from the insertion port 48. The film 12 sandwiched by the pair of rollers 50 is guided by a guide plate (not shown) (which is attached to the transport rack 38 or integrally formed), and is turned by approximately 90 ° to be a downward transport direction. It is designed to be sandwiched by the pair 32. Further, on the outlet side of the transport rack 38, a roller pair 52 in which a part of the lower roller is immersed in the processing liquid (developing liquid) is arranged. The line connecting the axes of the roller pair 52 is inclined, and has a role of transferring the film 12 to the fixing tank 20.
On the other hand, on the inlet side of the transport rack 40 of the fixing tank 20, a roller pair 54 in which a part of the lower roller is immersed in the processing liquid (fixing liquid) is provided, and the film from the developing tank 16 is reached. I am supposed to receive 12. The film 12 received is sandwiched by the roller pair 54, is directed downward, and is conveyed in a substantially U shape by the roller pair 32, 34, 36. On the outlet side of the transport rack 40, a roller pair 56 in which a part of the lower roller is immersed in the processing liquid (fixing liquid) is arranged. The line connecting the axes of the roller pair 56 is inclined, and has a role of transferring the film 12 to the rinse section 26.

The rinse section 26 includes a pair of rollers 58 provided on the transport rack 40 of the fixing tank 20. In the roller pair 58, the right side of the transport rack 40 in FIG.
It is attached to a portion extended in the direction, and a gap is provided between the fixing portion 20 and the water washing portion 30 by this extension. The side wall 20A of the fixing tank 20 forming this gap
The upper end of the side wall 28A of the washing tank 28 is integrated by the top plate 60. Vertical wall portions 62 parallel to each other are provided upright at the front and rear ends of the top plate 60 in the transport direction, and the recessed portion formed by the vertical wall portions 62 and the top plate 60 serves as the rinse tank 24.

A rinse liquid is stored in the rinse tank 24 and is scooped up by the lower roller of the roller pair 58 to wash the film surface and squeeze the fixing liquid.

The film 12 that has passed through the rinse section 26 is
It is sandwiched by a pair of rollers 64 provided on the inlet side of the transport rack 42 of the washing tank 28, the transport direction is changed downward, and thereafter, it is transported in a substantially U-shape by the roller pairs 32 and 36, and the roller pair on the outlet side. It is designed to be horizontally changed by 66. Here, the transport rack 42 of the washing tank 28 is extended on the right side in FIG. 1 toward the drying section 68, and a roller pair 70 is arranged. This roller pair 70
The film 12 is squeezed by being sandwiched between the two and is sent out to the drying section 68 in a horizontal state.

As described above, the film 12 has the insertion port 48.
Inserted from the transport racks 38, 40, 42 of the respective processing tanks
And is conveyed while being sequentially immersed in a developing solution, a fixing solution, and washing water, and is subjected to development, fixing, and washing treatments. Further, the film surface is washed with the rinse liquid while being transferred from the fixing bath 20 to the washing bath 28.

The drying section 68 includes a plurality of opposed roller pairs 72.
Are arranged at equal intervals. A guide plate 74 that guides the film 12 is disposed in the gap between the pair of opposed rollers 72 to surely move the film 12 to the next pair of opposed rollers 72.
To guide you. Here, the guide plate 74
Is integrally formed in the chamber 76 to which the dry air generated by the dry fan and the heater of the dry air generating means (not shown) is supplied. Guide plate 7 of this chamber 76
The mounting surface of No. 4 has slit holes 7 along the film width direction.
6A is provided, and the dry air is blown toward the film 12 from the gap between the pair of opposed rollers 72.
As a result, the film 12 is dried while being nipped and conveyed by the pair of opposed rollers 72, and reaches the discharge port 78.

In this automatic developing device 10, the film 12
Developer tank 16, fixing tank 20, rinse tank,
The developing solution, the fixing solution, the rinsing solution, and the washing water are replenished in the washing bath 24 and the washing bath 28, respectively. Further, the developing tank 16 and the fixing tank 20 are replenished with the developing solution and the fixing solution over time, so that the developing solution, the fixing solution, the rinsing solution, and the washing water maintain a predetermined processing ability. Each of the developing tank 16, the fixing tank 20, the rinsing tank 24, and the water washing tank 28 is provided with an overflow tank (not shown). When each processing solution is replenished, the overflow tank overflows from the processing tank. The treatment liquid is discharged as a waste liquid, and usually each treatment liquid is maintained at a substantially overflow level.

Further, the developing tank 16 and the fixing tank 20 are provided with a cartridge heater 80 for heating the developing solution and the fixing solution to a predetermined temperature. This cartridge heater 80
The heat generation is controlled by a control means (not shown), and the developing solution and the fixing solution in the developing tank 16 and the fixing tank 20 are heated and maintained at a temperature at which the film 12 can be processed in an optimum state. .

A liquid level sensor 82 to which the present invention is applied is arranged in the developing section 18 and the fixing section 22. The liquid surface level sensor 82 is configured to detect the liquid surface level by the detection unit 84 when the liquid surface level is lowered due to evaporation of the developing liquid and the fixing liquid and the liquid surface level is below a predetermined level. . Hereinafter, the detection unit 84 attached to the developing tank 16 of the developing unit 18 will be described as an example.

2 and 3, the liquid level sensor 82 is shown.
Is shown. This liquid level sensor 8
The second detection unit 84 includes a pair of electrodes 8 bent in a substantially L shape.
6A and 86B (hereinafter collectively referred to as “electrode 86”), one end of the pair of electrodes 86A and 86B is an electrode portion 88 immersed in the treatment liquid, and the other end thereof. Cable 90 connected to a detection device (not shown)
The lead wires 90A and 90B drawn out from are connected by caulking or the like, and the change of the energization state depending on whether or not both electrode portions 88 are immersed in the treatment liquid can be detected by this detection device. It has become. In this embodiment, the electrode 86 is formed by bending a stainless steel (SUS316) rod-shaped member in consideration of corrosion resistance to the developing solution and the fixing solution.

As shown in FIGS. 3A and 3B, each of the pair of electrodes 86A and 86B is inserted with a connecting portion from the intermediate portion to the lead wires 90A and 90B which is an end portion on the opposite side of the electrode portion 88. The electrode member 88 is covered with a covering member 100 formed of resin so as to be exposed. Further, in the covering member 100 which covers the respective electrodes 86A and 86B, the stabilizer portion 102 is integrally molded and held in shape so that the electrodes 86A and 86B do not scatter with each other and the relative position of the electrode portion 88 is disturbed. The covering member 10 which is the first resin for covering the electrode 86
As 0, it is preferable to use a thermoplastic resin having a large heat shrinkability, and in this embodiment, relatively inexpensive polypropylene is used. By using a resin having a large heat shrinkability, the resin 86 shrinks when it is heat-molded and then cooled, so that the electrode 86 can be closely adhered to the periphery of the electrode 86 to fix the electrode 86.

An elastic member 104 is formed around the covering member 100 covering the electrode 86. Detection unit 84
Forms an elastic member 104 by inserting the covering member 100 covering the electrode 86. Elastic member 104
For example, a rubber-like resin called an elastomer can be applied. In this embodiment, the elastic member 1
As 04, Santoprene (trade name, manufactured by AES Japan) is used.

As shown in FIGS. 2 and 3, the side plate 16 of the developing tank 16 is attached to the elastic member 104 of the detecting portion 84.
A groove portion 1 corresponding to the through hole 92 formed at a predetermined position of A.
The flange portion 108 is formed adjacent to the groove portion 106 and the groove portion 106. When the detecting unit 84 is attached to the developing tank 16, the electrode unit 88 is directed to the liquid surface side of the developing solution (the lower side of the paper surface of FIG. 3B), and the flange unit 1 on the opposite side of the electrode unit 88.
Insert the flange portion 108 from the 08 side while elastically deforming the flange portion 108 so that the groove portion 106 corresponds to the peripheral edge of the through hole 92,
The peripheral portion of the through hole 92 is fitted and fixed to the groove portion 106.

As a result, the detecting portion 84 of the liquid level sensor 82 is arranged between the side plate 16A of the developing tank 16 and the transport rack 38 housed in the developing tank 16. As for the position of the through hole 92, the lower end of each electrode portion 88 of the detecting portion 84 attached in this way is positioned at the lower limit level of the developing solution in the developing tank 14 (the liquid level shown by the solid line in FIG. 3B). It is provided to do so. Further, in the fixing tank 20, the detecting portion 84 of the liquid level sensor 82 is arranged between the side plate 20A of the fixing tank 20 and the transport rack 40 housed in the fixing tank 20 in substantially the same manner as the developing tank 16.

The liquid surface level sensor 82 is configured such that when the liquid developer in the developing tank 16 decreases and the liquid surface level becomes lower than the lower end of the electrode portion 88, the electrode portion 88 separates from the liquid surface and develops. It is possible to detect that the amount of liquid is insufficient.

In the automatic developing device 10, when the liquid level of the developing solution in the developing tank 16 falls below the lower limit level, the developing solution is replenished or the amount of the developing solution is decreased by an alarm or the like. It is supposed to announce.

The upper limit level of the liquid level of the developer in the developing tank 16 is substantially the overflow level (shown by the chain double-dashed line in FIG. 3B), and when the liquid level exceeds this overflow level, it is shown in the figure. The developer is designed to flow into the overflow tank or overflow pipe and be discharged.

The operation of this embodiment will be described below. The film 20 on which an image is recorded by exposure is inserted into the automatic developing device 10 through the insertion port 48 of the automatic developing device 10 and processed. In the automatic developing device 10, the film 12 inserted from the insertion port 48 is transferred to the transport rack 38 of the developing section 18.
The developing tank 1 is pulled in by the roller pair 50 provided in the developing tank 1.
Send to 6.

In the developing tank 16, a pair of rollers 32, 34 and 36 of a carrying rack 38 carry the developing treatment by immersing it in a developing solution while carrying it in a substantially U shape. The film 12 that has been processed by the developing unit 18 is sent to the fixing tank 20.
In the fixing tank 20, the roller pairs 32, 3 of the transport rack 40
The film 12 is conveyed while being guided in a substantially U-shape by means of Nos. Fixing tank 2
The film 12 that has been processed at 0 passes through the rinse section 26. When passing through the rinse portion 26, the roller pair 58
By being sandwiched between the film 12 and the fixing solution, the fixing solution is washed off by the rinse solution drawn up by the lower roller on the surface of the film 12, and the film 12 reaches the washing section 30.

In the washing tank 28 of the washing section 30, the film 12 is conveyed while being immersed in washing water by the conveying rollers 32 and 36 of the conveying rack 42 to wash the film 12 with water and remove the fixer component from the film. .

The film 12 that has been washed with water is squeezed and brought into a horizontal state before it reaches the drying section 68 from the washing section 30, and this horizontal state is maintained and the drying section 68 is maintained.
Is transported to. In the drying unit 68, the pair of opposed rollers 7
The film 12 is nipped by 2 and guided by a guide plate 74 to horizontally convey the film 12. At this time, the drying air is blown toward the front and back surfaces of the film 12 from the slit holes 76A provided in the chamber 76 to dry the film 12. The dried film 12 is discharged from the discharge port 78 to the outside of the machine and is stocked, for example, in a receiving box (not shown).

Here, in the automatic developing device 10, the developing tank 1
6. Since the liquid level sensor 82 is provided in the fixing tank 20, the developer and the fixing liquid evaporate when the operation of the apparatus is stopped,
When the liquid level falls below the lower limit level, such as when the developer and fixer are discharged to replace the developer and fixer, the electrode part 88 of the detection unit 84 is above the liquid level. The space between the pair of electrodes 86A and 86B is opened, and a detection device (not shown) detects that the amount of the processing liquid is insufficient. As a result, it is possible to prevent the cartridge heater 80 from being heated.

Normally, the liquid level sensor 82 has a detector 8
The electrode part 88 of No. 4 is immersed in the developing solution in the developing tank 16. Therefore, due to the surface tension of the developer, the developer adheres to the electrode portion 88 above the liquid surface. The developer adhering to the electrode portion 88 tries to permeate from the electrode portion 88 between the electrode 86 and the covering member 100 or between the covering member 100 and the elastic member 104, but the covering member 100 has a large heat shrinkability. Since it is made of a material, the covering member 100 is in close contact with the periphery of the electrode 86, so that the developing solution does not soak into it.

Even if the developing solution permeates between the covering member 100 and the electrode 86 for some reason, the electrode 86A,
Since 86B is individually coated on the coating member 100,
The soaked developing solution does not change the energization state between the electrodes 86A and 86B inside the detecting section 84, and the malfunction of the detecting section 84 due to the soaking of the developing solution can be reliably prevented.

The covering member 100 is inserted between the covering member 100 and the elastic member 104 to insert the elastic member 10 into the elastic member 10.
Since 4 is molded, the covering member 1 is heated by the heat during molding.
Part of No. 00 is melted and welded to the elastic member 104 to be firmly adhered. Thereby, the covering member 100 and the elastic member 1
There is no gap between the nozzles 04 and 04 into which the developer penetrates. Further, even if the developing solution permeates, the permeating developing solution does not adhere to the electrode 86.

When the detecting portion 84 of the liquid level sensor 82 is attached to the developing portion 14, the side plate 16 of the developing tank 16 is attached.
The elastic member 104 is inserted into the through hole 92 provided at a predetermined position of A.
It can be easily attached and fixed simply by inserting it while elastically deforming it. Thus, the electrodes 86A, 86
Since the cover member 100 covering B is covered with the elastic member 104 in a double structure, the attachment is extremely easy.

In this embodiment, the liquid level sensor 8
Although 2 is provided in the developing tank 16 and the fixing tank 20, it may be provided in the rinse tank 24 and the washing tank 28. Further, the detection unit 84 is
This is an example to which the present invention is applied, and the shape of the electrode 86, the shape of the covering member 100, and the elastic member 104 and the material thereof are not limited, and the electrode is formed of a general conductive material. be able to. Further, the covering member 100 is not limited to polypropylene, and any thermoplastic resin having a large heat shrinkability may be used.
A material having water resistance or the like is preferable, and as the elastic member 104, a general resin material having elasticity can be applied.

In this embodiment, the liquid level sensor 82
Although the lower limit level of the liquid level of the developing solution (fixing solution) is detected by the above, it is of course possible to apply to a configuration in which the upper limit level of the liquid level is detected.

Further, in the present embodiment, the present invention has been described by applying it to the automatic developing device 10 for processing the image-exposed film 12, but the present invention is applicable to other photosensitive materials such as photographic paper and lithographic printing plates. It is needless to say that it may be applied to a photosensitive material processing apparatus for processing a material, and it can also be applied as a general electrode type liquid level sensor for detecting a liquid level.

[0049]

As described above, in the liquid level sensor of the present invention, the detecting portion is double insert-molded with the first resin and the resin having elasticity, so that the permeation of the processing liquid or the like is ensured. Therefore, it is possible to reliably prevent a change in the energization state of the detection unit and a malfunction due to the permeation of the treatment liquid, and it is possible to obtain an excellent effect of accurately detecting a predetermined liquid surface level.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic developing device applied to this embodiment.

FIG. 2 is a perspective view showing a detection unit of a liquid level sensor to which the present invention is applied.

3A is a sectional view of a main part taken along the line 3B-3B in FIG. 2, and FIG. 3B is a sectional view of a main part taken along the line 3A-3A in FIG.

[Explanation of symbols]

 10 Automatic Developing Device 12 Film 16 Developing Tank 20 Fixing Tank 82 Liquid Level Sensor 84 Detection Unit 86 Electrodes 90A, 90B Lead Wire (Wiring) 100 Covering Member (First Resin) 104 Elastic Member (Resin Having Elasticity)

Claims (2)

[Claims] 1. A liquid level sensor capable of detecting whether or not the tips of a pair of electrodes forming a detection unit are in contact with a liquid, wherein the pair of electrodes of the detection unit and the electrodes are electrically connected to each other. Of the first resin is insert-molded around the periphery of the connection portion with the wiring to be electrically connected, and the molding portion made of the first resin has elasticity in a state where these electrodes are held in a predetermined positional relationship. A liquid level sensor, which is insert-molded with a second resin. 2. The liquid level sensor according to claim 1, wherein the first resin is a resin having a large heat shrinkability.