EP0040328A1 - Developing apparatus with stirring facility - Google Patents

Abstract

In a developing device (11), a magnetic rotor (29), which rotates close to a wall (23) and rotates the liquid, is provided under the liquid surface (22). Outside the trough (24, 26) there is a rotating field magnet arrangement (28) which acts on the magnetic rotor (29) with its magnetic field and sets it in rotation. There are no parts penetrating the wall. The magnetic fields can be formed by permanent magnets which are driven by a motor (49).

Description

The invention relates to a developing device for photosensitive material, with a device housing with a plurality of treatment stations, each of which has a trough filled with a chemically active liquid which is circulated in order to achieve constant temperature and concentration, through which the photosensitive material is guided with transport devices.

In particular, the invention relates to small development devices, each with trough fillings of approximately 1 to 5 liters. Such small devices are employed either as tableware or as small-size inlet _{zel he} g ät _e, optionally on a rack in the trade, and particularly in the medical, dental, and in the graphic area. In the medical and dental field, the photosensitive material to be developed is primarily X-ray films. In the graphic arts, mainly light-sensitive films or light-sensitive coated paper are developed. In these areas, film development is only carried out as part-time work by personnel not specially trained for this purpose. With these small devices, therefore, greater emphasis must be placed on simple construction and ease of use.

Experience shows that untrained personnel make operating errors, especially when replacing the treatment fluids and cleaning the troughs. This work is to be carried out at approximately weekly intervals, and also at longer intervals if there is only a small amount of film. First, the treatment liquids have to be drained, pumped out or poured out, then the troughs have to be rinsed with a cleaning liquid, the cleaning liquid is washed out with water, and then the new treatment liquids are poured in. A particular complication in this cleaning work arises from the fact that not only the troughs but also the liquid circulation system belonging to each trough has to be cleaned. The liquids are continuously pumped around in order to achieve constant temperature and concentration. This is necessary in order to achieve a perfect quality of the developed image. The circulation is generally carried out by a pump, which is often housed in the supply part of the device, and which is connected to the trough by a drain and an inflow line. After draining the liquid in a trough, the trough and the pump system are rinsed with a cleaning liquid. Then the cleaning liquid must be removed very carefully, otherwise it will be the freshly filled one Liquid chemically destroyed. The pump system must therefore be carefully rinsed several times with fresh water. errors often occur due to negligence, so that the cleaning liquid is not completely removed, which means that the newly filled liquid either completely or at least. a certain percentage is chemically destroyed, so that it will soon have to be renewed in order to achieve perfect image quality.

The invention is based on the task of specifying a generic development device with a circulating device which can be easily and quickly cleaned even by untrained personnel without special precautionary measures and which provides sufficient circulation for achieving constant temperature and concentration of the circulated liquid.

According to the invention, it is provided that in a generic development device close to a wall lying below the liquid surface, a magnetic rotor which circulates the liquid is rotatably guided with an axis of rotation perpendicular to the wall, which has a magnetic field component perpendicular to the axis of rotation, and that outside of the trough one with its magnetic field rotating field magnet arrangement acting on the magnetic rotor is attached.

This embodiment of a circulating device has the advantage that the inflow and outflow lines to a pump are eliminated, and rather the circulating device itself sits directly in the liquid trough. This also cleans and rinses the circulating device when cleaning the trough and washing the trough with clean water. This eliminates the need to rinse the pump circuit several times. However, this also eliminates the possibility of errors that have always led to unclean work with untrained personnel.

Destruction of a pump due to dry running is also excluded.

The circulation of liquid through magnetically driven rods has long been in chemical laboratories and the magnetic stirrers used there known. These magnetic stirrers usually have a heating plate and a bar magnet rotatably arranged beneath it. A glass vessel with the liquid therein is usually placed on such a magnetic stirrer, into which a bar magnet, which is encased by glass or by another material that is not attacked by the liquid, is inserted. When the inserted bar magnet is correctly positioned with respect to the bar magnet of the stirrer, the inserted bar magnet is carried along by the driven bar magnet of the stirrer and rotated in the glass vessel. That flawless. free work of this magnetic stirrer is continuously monitored by laboratory personnel. It is critical to pay attention to the speed of rotation of the stirrer, since the inserted bar magnet is thrown out of the force field of the driving bar magnet if the speed of rotation is too high. This happens especially often when the viscosity of the stirred liquid is reduced by increasing the temperature or by dilution or by stirring itself. A direct application of such a magnetic stirrer is completely impossible in the present case, since it is presupposed here that the stirrer is continuously observable and that the observation and monitoring are also added. done by trained laboratory personnel. The invention makes use of the principle of the magnetic stirrer and specifies a structure which can also be used for use by untrained personnel, in an opaque trough in which transport devices and photosensitive material are located, which is nevertheless extremely simple in construction and yet always works reliably and without the risk of damage to the photosensitive material and ensures the sufficient circulation of the liquid to achieve constant temperature and concentration.

stand zur Transporteinrichtung für das fotosensitive Material vorliegt. Der beste Ort zur Anbringung hängt daher in der Regel von der Ausführung der Transporteinrichtung ab. Ein besonders einfacher Aufbau ergibt sich dann, wenn der Zapfen direkt an die Trogwand, aus demselben Material, aus dem die Trogwand besteht, angeformt ist.It contributes to the simple construction of the circulating device if the pin guiding the magnetic rotor is firmly connected to the trough wall. The trough wall is understood to mean either a side wall or the bottom of a trough. The magnetic rotor and its housing is placed in such a place below the surface of the liquid that sufficient

stood for the transport facility for the photosensitive material. The best place to attach therefore usually depends on the design of the transport equipment. A particularly simple construction results when the pin is molded directly onto the trough wall, from the same material from which the trough wall is made.

In order to further reduce the risk of damage to the magnetic rotor, it is advantageous not only to guide it, but also to protect it by a housing which has at least one inlet opening and at least one outlet opening. Such a housing also helps to guide the circulated liquid in a predetermined direction. For this purpose, it is particularly advantageous if the inlet opening is in the top surface of the rotor housing, if the peripheral surface of the housing is circular, and if the outlet opening is provided in the peripheral surface, with mutually parallel walls, one of which is the wall which is further away from the rotor housing axis forms a tangent surface to the circular inner peripheral surface. The housing is then aligned so that this tangent surface points in the direction in which the escaping liquid is to be circulated.

For example, a simple bar magnet can be used as a magnetic rotor. However, since a rotating movement is carried out, it is advantageous to use a circular magnet, since a plurality of alternating poles can be magnetized on its circumference, so that a particularly strong coupling results with a driving magnetic field.

The magnetic rotor can have a metallic magnet. However, it is more advantageous to use a magnetic oxide ceramic, advantageously a hard ferritic material, since these materials permit significantly higher magnetizations. Since these magnetic oxide ceramics are often fragile, it is advantageous to shrink them into a plastic circulation wheel. This plastic circulation wheel is also advantageously designed to be circularly symmetrical.

The plastic circulation wheel or the ring magnet itself can run directly on the peg attached to the trough wall. However, the pin is worn out. This is particularly disadvantageous if the pin is molded directly onto the trough wall, since it can then no longer be replaced. It is therefore advantageous if the plastic circulation wheel runs on an oxide ceramic bushing which is fastened to the journal and engages in the circulation wheel. If the plastic circulation wheel or the oxide ceramic bushing becomes worn, these can be easily replaced. In order to ensure that the oxide ceramic bush placed on the pin does not rotate around the pin and thus wears it, it is advantageous if the oxide ceramic bush has a recess on its side facing the trough wall into which an anti-twist device attached to the trough wall engages.

With amounts of liquid from 1 to 3 1 in a trough, it is sufficient, with amounts of liquid up to 1 1, it is even very advantageous if the plastic circulating wheel has a completely smooth rim on its outer peripheral surface. For larger quantities of liquid, however, it is advantageous to provide the outer peripheral surface of the plastic circulating wheel with wings.

In order to promote the simple and good cleaning of the circulating device, it is advantageous to arrange the lower surface of the plastic circulating wheel at a distance from the trough wall that allows the liquid between the trough wall and the lower surface to drain freely. This means that the cleaning liquid and the rinsing water can easily penetrate into this space.

The rotating field magnetar driving the magnetic rotor also has a particularly simple embodiment, rotating. driven permanent magnet. If the magnetic rotor has a circular ring magnet, it is advantageous if the permanent magnet of the rotating field magnet arrangement is also designed as a circular ring magnet, which results in a particularly good coupling between the two magnets. The arrangement of such a ring magnet on the axis of an electric motor leads to a particularly simple and inexpensive design.

The rotating field magnet arrangement has a very low weight, which is particularly important for small devices, if it has electromagnets which can be connected in succession and are arranged in a circle of approximately the diameter of the magnetic rotor. The circuit for sequentially connecting the electromagnets advantageously consists of integrated circuits which make up only a small fraction of the weight of an electric motor. Such a rotating field magnet arrangement is therefore considerably lighter than one which has an electric motor.

For all embodiments of the proposed development device, the reduction in the weight of the circulating device and thus the entire device is a very considerable advantage over known devices. The proposed construction also leads to a considerably smaller space requirement for the proposed circulating device compared to conventional circulating devices. This space saving also contributes to the weight reduction of the device and leads to a compact design, as is particularly required for small devices, in particular table-top devices.

It contributes to the ease of operation and maintenance of the proposed circulating device if the rotating field magnet arrangement and the associated operating resources are arranged on an insert that can be inserted into the device housing and can be electrically contacted with it. In the whole arrangement, the electric motor or the integrated circuits are practically the only components that can be defective. It doesn't have to be like that with previous circulation devices, the entire device housing is opened, the pump is removed and replaced, it is simply sufficient to pull out the insert with the rotating field magnet arrangement and to insert a new insert. The device is then immediately ready for use again. The slot can be easily repaired outside the device without restricting the usage time of the development device. A particularly simple construction is obtained when the rotating field magnet arrangements of several adjacent troughs have a common insert. This is particularly advantageous if the magnets of the rotating field magnet arrangements have common resources, for example only one common electric motor.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated by 7 figures.

• Fig. 1 Eine perspektivische Ansicht eines Entwicklungsgerätes mit vorgeschlagener Umwälzeinrichtung;
• Fig. 2 .einen Schnitt durch einen auf einem Zapfen befestigten Magnetläufer in einem Läufergehäuse;
• Fig. 3 eine Ansicht in das Läufergehäuse von unten;
• Fig. 4 einen Querschnitt durch das Läufergehäuse;
• Fig. 5 eine perspektivische Ansicht eines Kunststoffumwälzrades mit Flügeln;
• Fig. 6 einen Schnitt durch eine Drehfeldmagnetanordnung zum Antreiben eines Magnetläufers gemäß Fig. 2;
• Fig. 7 eine perspektivische Ansicht einer weiteren Dreh- .feldmagnetanordnung zum Antreiben eines Magnetläufers gemäß Fig. 2.

Show it:

• Fig. 1 is a perspective view of a developing device with proposed circulation device;
• 2 shows a section through a magnetic rotor fastened to a pin in a rotor housing;
• Figure 3 is a view into the rotor housing from below.
• 4 shows a cross section through the rotor housing;
• Fig. 5 is a perspective view of a plastic circulating wheel with wings;
• 6 shows a section through a rotating field magnet arrangement for driving a magnetic rotor according to FIG. 2;
• 7 shows a perspective view of a further rotary field magnet arrangement for driving a magnetic rotor according to FIG. 2.

In Fig. 1, .ll denotes the housing of a table development device for photosensitive material. This consists of a lower housing part 12 and an upper housing part 13. The lower housing part is divided by a plurality of walls 14 into treatment stations. On its front side, the lower housing part 12 has a film input point 15 through which the photosensitive material is introduced into the developing device. The photosensitive material is then taken over by transport devices 16, which are shown here as rollers. These transport rollers are driven by gears and / or toothed belt drives at circumferential speeds that are equal to one another. The path of the photosensitive material is shown in dashed lines and designated 17. The material first gets into the developer liquid 18 of a development station, from there it is fed via the transport rollers 16 into the fixing liquid 19 of a fixing station, then gets into the water 20 of a washing station via further transport rollers and is transported from there into the upper housing part 13, in this Area dried and then ejected through a film delivery point 21. Decisive for the invention, however, is not the overall design of the development device, of which many other embodiments besides the one described here exist and are conceivable, but rather the circulating devices for the liquids of the treatment stations.

The liquid level of the different liquids of the treatment stations is assumed to be the same and is shown in dash-dot lines in FIG. 1 and is designated by 22. However, it is irrelevant to the invention whether the different liquid levels are the same or different. 1 shows a rotor housing 25 of a proposed circulation device below the liquid level 22 of the developer liquid 18 at the bottom 23 of the development trough 24. A corresponding housing 25 is partially shown on the bottom of the fixing trough 26.

The device housing 11 has a recess 27 on one side surface of its lower part 12, into which a recess, in FIG. 1 withdrawn insert shown with rotating field magnet assembly 28 can be inserted. The inserted slot is located exactly under the housings 25.

2 shows a particularly advantageous embodiment of the assembly of a magnetic rotor 29. A pin 30 is formed on the bottom 23 of a treatment station. An oxide ceramic bushing 31, which advantageously consists of aluminum oxide ceramic, is pushed over the pin. The bottom 23 also has an anti-rotation lock 32 formed on it and the pin 30, which engages in a recess 33 in the oxide ceramic bushing and prevents it from rotating with respect to the pin 30. On this oxide ceramic bushing 31 runs a circularly symmetrical plastic circulating wheel 34 into which an annular magnet 35 is shrunk. This magnet is magnetized so that it has a magnetic component perpendicular to the pin. In the illustrated case there is a south pole S to the right of the pin and a north pole N to the left of the pin. A rotor housing 36 is placed over this entire arrangement, which, like the oxide ceramic bushing 31, is held by a screw 37 screwed into the pin 30. The rotor housing 36 has liquid inlet openings 39 on its top surface 38 and a liquid outlet opening 41 on its outer peripheral surface 39.

The magnetic rotor 29 does not necessarily have to be guided on the pin 30. Rather, it is possible that, for example, no pin is provided at all, but that the housing is otherwise attached to the trough, and that the magnetic rotor is guided through the inner peripheral surface 42 of the housing.

The plastic circulation wheel 34 has a lower surface 43 designed as a flat circular ring surface. It is attached to the oxide ceramic bushing 31 in such a way that there is a distance 58 between the trough bottom 23 and the lower surface _57, which allows the liquid located between the trough bottom and the lower surface to drain freely. The liquid must then be out of this area run off when the treatment liquid or the cleaning liquid or the rinsing water is drained from a trough. The draining expediently takes place through an opening located at the bottom 23 of the trough. However, the liquids can also be pumped out or poured out. For very small development devices with trough fillings of about 1 liter, pouring out is the cheapest, for larger devices, draining has proven to be the most convenient. The proposed circulation device can be run during the entire cleaning and rinsing process. As a result, the circulation device will certainly be flushed well. With previous pumps, this was not always permitted since many liquid pumps may only be operated if they are actually permeated with liquid. The pumps were therefore constantly on and off during the cleaning and rinsing processes. The proposed circulating device can also run dry over a long period of time, since the plastic circulating wheel on the oxide ceramic bushing runs well even without liquid lubrication.

Fig. 3 shows a rotor frame 36 strength in a view from below and _F. 4 shows a cross section through such a housing. There are liquid inlet openings 39 which are offset from one another by 120 ° in the cover surface 38 of the housing. The inner peripheral surface 42 and the outer peripheral surface 40 are circular. The liquid outlet opening 41 is guided as a recess let in from the bottom of the housing. It has two side walls and an upper wall 43. The side wall 44, which is closer to the central axis 45, and the side wall 46, which is further away from the central axis 45, are parallel to each other. The further away wall 46 is designed as a tangent surface to the inner peripheral surface 42. The circulated liquid is expelled tangentially to the circumferential surface of the magnetic rotor through this liquid outlet opening. The housing is mounted on the trough wall so that the liquid in question is circulated in a predetermined direction.

FIG. 5 shows a perspective view of a plastic circulating wheel 34 which has vanes 47 to increase the pumping capacity. Such a plastic circulation wheel can be used when large amounts of liquid, e.g. from 3 1 trough filling, must be circulated.

FIG. 6 shows a section through a rotating field magnet arrangement as can be used for driving a magnetic rotor according to FIG. 2. An electric motor 49 is fastened to a fastening part 48, on the axis 50 of which a plastic magnetic fastening wheel is held by means of a screw 52 turned into the axis 50. An annular magnet 53 is shrunk into the plastic magnet fastening wheel. This can consist of a metallic magnet, but is advantageously made of an oxidic material, preferably a ferrite. Particularly high magnetic field strengths can be achieved with a ferrite. The ring magnet is magnetized so that it has a component perpendicular to the axis of rotation 50. In the sectional view, this is indicated by a north pole N to the right of the axis and a south pole S to the left of the axis. The circular ring magnets 35 and 53 are preferably magnetized identically by the magnetic rotor 29 or the rotating field magnet arrangement 48, so that there is a particularly large interaction between the two.

The rotating field magnet arrangement is attached under the magnetic rotor located inside the trough in such a way that the axis of rotation 50 of the electric motor 49 coincides with the axis of rotation of the magnetic rotor. In the exemplary embodiment according to FIG. 1, magnetic rotors are provided in two adjacent troughs, specifically in the development trough 24 and in the fixing trough 26. These are each driven by a ring magnet arranged on a common insert. The circular ring magnets are either driven by a separate electric motor or by a common electric motor.

FIG. 7 shows a further embodiment of a rotating field magnet arrangement 28, which is inserted directly as an insert according to FIG Recess 27 of a device housing 11 can be used. Six electromagnets 55, which are arranged in a circle 59 approximately of the magnetic rotor diameter, are fastened on a common fastening plate 54. Each electromagnet 55 has two connections 56 through which it is supplied with electrical energy. The magnets are switched in sequence, so that a rotating magnetic field is generated. This sequential wiring is carried out by using commercially available integrated circuits. Such an embodiment can be made particularly light and compact.

The exemplary embodiments shown show that the proposed circulating device allows a particularly light and compact structure of a developing device. It also results in a very simple operation of such a device in terms of its cleaning and maintenance. The proposed development device is therefore particularly advantageous especially for small devices, which typically have trough fillings of approximately 1 to 5 liters each and are often designed as table devices, since these devices are almost always operated by non-specially trained personnel.

Reference symbol list

• 11 housing
• 12 lower housing part
• 13 upper housing part
• 14 walls
• 15 film entry point
• 16 transport rollers
• 17 film track
• 18 developing liquid
• 19 fixing liquid
• 20 water
• 21 film issuing office
• 22 liquid level
• 23 floor
• 24 development trough
• 25 rotor housing
• .26 Fixation trough
• 27 recess for 28
• 28 rotating field magnet arrangement
• 29 magnetic rotor
• 30 cones
• 31 oxide ceramic bushing
• 32 Anti-rotation device
• 33 recess for 32
• 34 plastic circulation wheel
• 35 circular magnet
• 36 rotor housing
• 37 screw
• 38 top surface
• 39 liquid inlet opening
• 40 outer peripheral surface
• 41 liquid outlet opening
• 42 inner circumferential surface
• 43 top wall
• 44 side near wall
• 45 axis
• 46 wide side wall
• 47 wings
• 48 fastening part
• 49 electric motor
• 50 axis
• 51 plastic magnetic fastener
• 52 screw
• 53 circular magnet
• 54 mounting plate
• 55 electromagnets
• 56 connections
• 57 lower surface
• 58 distance
• 59 circle,

Claims (16)

1. Development device for photosensitive material with a device housing, with several treatment stations, each of which has a trough filled with a chemically active liquid circulated to achieve constant temperature and constant concentration, through which the photosensitive material is guided with transport devices, as characterized by that close to a wall (23) lying below the liquid surface (22) a liquid-circulating magnetic rotor (29) with a perpendicular to the wall (23) axis of rotation (30) is rotatably guided, which has a perpendicular to the axis of rotation magnetic field component, and that outside of the trough (24, 26) a rotating field magnet arrangement (28) is applied with its magnetic field to the magnetic rotor (29). 2. Development device according to claim 1, characterized in that the magnetic rotor (29) through a with the trough wall (23) fixedly connected pin (30) is guided. 3. Development device according to claim 1 or 2, characterized in that a rotor housing surrounding the magnetic rotor (36) is provided with at least one inlet opening (39) and with at least one outlet opening (41). 4. Development device according to claim 3, characterized in that the inlet opening (39) in the top surface (38) of the rotor housing (36), that the inner peripheral surface (42) of the housing is circular and that the outlet opening is provided in the peripheral surface , With mutually parallel walls (44, 46), of which the wall (46) further away from the rotor housing axis (30) forms a tangent surface to the circular inner peripheral surface (42). 5. Development device according to one of the preceding claims, characterized in that the magnetic rotor (29) has an annular magnet (35). 6. Development device according to claim 5, characterized in that the ring magnet consists of oxide ceramics and is shrunk into a circular symmetrical plastic wheel (34). 7. Development device according to claim 6, characterized in that the plastic circulation wheel (34) on an attached to the pin (30) and engaging in the Umwälzrad oxide ceramic bushing (31). 8. Development device according to claim 7, characterized in that the oxide ceramic bushing (31) on its side facing the trough wall (23) has a recess (33) into which an anti-rotation lock (32) attached to the trough wall engages. 9. Development device according to one of claims 6 to 8, characterized in that the plastic circulation wheel (34) has wings (47) on its outer peripheral surface. 10. Development device according to one of claims 6 to ₉ , _d a - characterized in that the lower surface (57) of the plastic circulating wheel (34) in a free drainage of the liquid between the trough wall (23) and the lower surface (57) allowing distance ( 58) from the trough wall (23). 11. Development device according to one of the preceding claims, characterized in that the rotating field magnet arrangement (28) has a rotationally driven permanent magnet (53). 12. Development device according to claim 11, characterized in that the permanent magnet is a on the axis (50) of an electric motor (49) arranged annular magnet (53). 13. Development device according to one of claims 1 to 10, characterized in that the rotating field magnet arrangement (28) in a circle (59) arranged approximately the magnet rotor diameter, sequentially switchable electromagnets (55). 14. Development device according to one of the preceding claims, characterized in that the rotating field magnet arrangement (28) and the associated operating are arranged on an insert that can be inserted into the device housing (11) and can be electrically contacted with it. 15. Development device according to claim 14, characterized in that a common insert is provided for the rotating field magnet assemblies (28) of a plurality of adjacent troughs (24, 26). 16. Development device according to claim 15, characterized in that the rotating field magnet arrangements have common resources.

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