WO2006012897A1

WO2006012897A1 - Ink refill system

Info

Publication number: WO2006012897A1
Application number: PCT/DK2004/000528
Authority: WO
Inventors: Michael JØRGENSEN
Original assignee: Enilorak Aps
Priority date: 2004-08-06
Filing date: 2004-08-06
Publication date: 2006-02-09

Abstract

A continuous ink refill system (5) is disclosed for continuously refilling an ink cassette arranged in a printing device, where said refill system comprises an ink reservoir (6), valve means (7) arranged substantially at the bottom of said reservoir, an ink tube connected to said valve, where the tube comprises means for a liquid tight connection to an ink cassette in a printing device, and that a sensor device (13) is arranged for registering the ink level in the cassette and further that the sensor comprises means for generating control signais for controlling the valve means.

Description

Ink refill system

The present invention relates to an ink refill system for continuously refilling of an ink cassette arranged in a printing device.

Colour printers for printing large format prints are often equipped with a battery con¬ sisting of six toner cassettes wherein inks of different colours are provided. For indus¬ trial purposes, the printers are often supplied with two sets of six cassettes in order to increase the production speed and ink capacity such that continuous printing with fewer stops may be achieved and thereby the productivity of the single printer may be increased.

The ink cassettes are fairly standard, i.e. the single cassettes may be used for a number of different brands of printers, and these cassettes have more or less become a standard in this particular technical field. The cassettes are mounted in the printer such that there is a connection between the ink cassette and the movable printing head which will usually transverse the media to be printed on in order to deposit the ink on the media. The printer heads will usually be of the ink jet type controlled by a micro proc¬ essor. These systems are well-known in the art and are not included in the scope of the present invention.

One problem, however, with the known printers is that the cassettes need to be re¬ placed from time to time in order to maintain a sufficient supply of ink. Although the cassettes have a fairly large volume, it is only possible to fill ink in the cassette corre¬ sponding to a volume to approximately 1/5 to 1/8 of the volume. This is due to the fact that in order to be able to maintain the rate of printing, i.e. depositing of ink through the printing head, the pressure in the ink cassette must remain substantially constant and preferably slightly below the ambient air pressure in order not to force or push the ink through to the printing head.

The ink is usually supplied in six or eight different colours, black, lilac, magenta, yel¬ low, light lilac and light magenta, orange or green, such that by combining these six colours by means of the micro processor and the ink jet printing head, it becomes pos¬ sible to print pictures as very natural and high quality images.

Obviously, depending on the task at hand, more or less of each colour may be required such that one of the colours needs to be replenished, i.e. the cassette needs to be re¬ placed more often than other cassettes. For practical purposes however, it is often such that when the printers stop in order to change the cassette, all the cassettes or a sub¬ stantial part of the cassettes are replaced in order to avoid further print stops interrupt¬ ing the printing process. This obviously leads to an unnecessary waste in that cassettes which have almost but not completely been used up are wasted. In other systems, two cassettes of each colour are supplied such that as one cassette is emptied, an automatic shift to the other cassette will occur such that the first cassette may be replaced whereby a substantially continuous printing may be achieved. Each cassette contains a limited amount of ink usually in the standard configuration suitable for the industrially developed printers around 220 ml. For most print jobs, this corresponds to approxi¬ mately two hours of continuous printing depending on the mix of ink in order to achieve the desired finished print.

It is an object of the present invention to provide an ink refill system which is suitable for use with the standard cassettes such that the cassettes may be refilled for much longer continuous printing time without having to interrupt the printing process due to replacement of the ink cassettes. ' - -

The present invention addresses this by providing a continuous ink refill system for continuous refilling an ink cassette arranged in a printing device where said refill sys¬ tem comprises an ink reservoir, valve means arranged substantially at the bottom of said reservoir, an ink tube connected to said valve, where the tube comprises means for a liquid tight connection to an ink cassette in a printing device, and that a sensor device is arranged for registering the ink level in the cassette and further that the sen- sor comprises means for generating control signals for controlling the valve means.

Although the available volume in the cassette is substantially larger than the amount of ink present, it is due to the fact that as the ink is dispensed from the cassette, a certain under pressure will occur inside the cassette. Therefore, by providing a large air vol¬ ume inside the cassette, a substantial continuous and very accurate flow of ink to the printer head may be achieved as the printer head will substantially suck out the ink from the cassette. By providing a reservoir comprising a valve and a sensor device which will register the ink level in the cassette, it is possible to replenish the cassette up to a predetermined level such that the under pressure/vacuum created inside the cassette due to the suction from the printer head is not interrupted which could cause a lowering of the quality of the finish printed product.

In a further advantageous embodiment, the valve means is an electrically operated magnetic valve device. Although other valve devices may be used, such as for exam¬ ple manual valves, valves activated by air pressure/vacuum, it has been found that within the scope of the present invention, a reliable working and very well-controlled running of the system may be achieved by using magnetic valve devices.

In a further advantageous embodiment of the invention, a control box is provided where the input from the sensor is translated to a control signal for the valve, and op¬ tionally that the input may further control one or more diodes and/or alarms and/or generate a status report transmitted to an external device. The control box provides the possibility for adding further features to the system such that maintenance may be fa¬ cilitated in an easy way in that in the optional embodiment where diodes, alarms or status reports are activated/generated by the control box, the personnel overseeing the printing device may readily and easily detect the status of the entire system in that also the substantially larger ink reservoirs in comparison to the ink cassettes may be in need of replenishment, a magnetic valve may have become stuck or other necessary maintenance tasks are required. Furthermore, it is possible to detect and thereby gen¬ erate a special warning ahead of the time where the replenishment of the ink reservoirs is required. Therefore, by providing visual indications in the shape transparent reser¬ voirs of diodes, alarms or the like, the usability of the printing device, especially in relation to the ink status, may be improved in such a way that it is possible for an op¬ erator to operate more printers with less down time. In a further advantageous embodiment, the sensor device and/or the tube is connected by means of a snap coupling, such that the tube and/or the electrical wire may be dis¬ engaged from the system. By providing for example snap couplings, the system may be disengaged very quickly and easily such that in case of malfunction or cleaning chores, a new and proper working reservoir may be installed by simply snapping on the appropriate connections.

In a further advantageous embodiment, the reservoirs are arranged on a mounting bracket, and that optical means for indicating the status of the system are arranged on the bracket and that the bracket is arranged at a distance from the cassette. By provid¬ ing the reservoirs in a mounting bracket, the system may easily be adapted to be in¬ stalled on already existing printer units in that the bracket may be shaped such that it can be attached to the printing unit. Due to the fact that tubes and wires are provided between the reservoir and the cassette, the bracket including the reservoirs may be arranged on the printing unit at a suitable position at a distance from the cassette. Fur¬ thermore, by arranging one or more reservoirs in a mounting bracket, including the optical indication means for providing status on the system, on the outside of said bracket, it is very easy to provide a complete set of for example six reservoirs arranged in one mounting bracket for installation on a printing unit such that the printing unit may be upgraded in one operation to include a system according to the present inven¬ tion. In this way, the system is not dependent on any particular configuration of the printer. • - ■■• ■ •• •■ ■ ^• • • ^•

In a further advantageous embodiment, one or more cassettes are provided, and that each cassette is of double configuration, such that each cassette is generally U shaped and having a height corresponding to a standard cassette, and that at one or both the free ends of the two legs of the U, the cassette is provided with interface means for allowing ink to be communicated between the cassette and the printer head, and that the dimensions of the legs substantially corresponds to the dimensions of a standard cassette, and further that the distance between the legs of the U corresponds to the distance between the interface means arranged in the printer, and further that the vol¬ ume at the bottom of the U is allowing liquid communication between the volumes in the legs of the U. Although it is customary to have six cassettes, each containing dif- ferent colours as described above, for larger printers, it is also well-known to have a double bank of cassettes, i.e. twelve cassettes where two cassettes of each colour is provided in order to provide for a longer continuous printing. However, by providing a cassette which is double, i.e. comprises the volume of two cassettes plus the extra vol- ume connecting the two cassettes, it is possible to adapt the present system to theses systems where double cassettes, i.e. twelve cassettes in order to provide the entire col¬ our scale, are already provided. One of the advantages with having 2 sets of six cas¬ settes as in the prior art devices, is the fact that substantially continuous printing may be achieved as the printer head may be supplied with ink from one ink cassette while the other is being replaced. With the present system this is not necessary as continuous refilling of the cassettes occurs.

The inventive cassette being generally of a U-shape such that each leg of the U corre¬ sponds substantially to a standard cassette for use with the particular printer and con- necting this to the refill system, substantial savings in the amount of valves, control box, wiring, tubes etc. may be achieved whereby the overall cost of the system is re¬ duced, and at the same time, the usability of the system is greatly improved.

hi a still further advantageous embodiment, one or more cassettes are provided and each cassette is integrated with the reservoir, and further that the level sensor, valve, tubing, wiring, control box and optionally other features are integrated in the cassette, such that the cassette extends upwards and/or rearwards from an engagement section with the printer. In this embodiment, the need for a mounting bracket and any extra adaptations to be implemented on the printer is avoided in that the entire refill system is integrated into the cassette. The cassette typically has an engagement section which is adapted to be inserted into the printer for fluid communication between the ink pre¬ sent in the cassette and the printer head. The dimensions of the engagement section are maintained such that the integrated system according to this embodiment may be in¬ serted into the fairly standardised cassette engagement sections in the printers. The part of the cassette extending outside the printer is enlarged either outwards or rear¬ wards of the engagement section in order to provide the extra volume which will both accommodate the ink reservoir and also the valve, level sensor, printed circuit board of the control box etc. and etc. It has further been found with tests with a device with integrated reservoir that part of the volume of the cassette which were formally air filled in order to control the air pressure as described above may be used as an ink reservoir in that the magnetic valve may be programmed by means of the control circuitry comprised in the control box in conjunction with the level of the level sensor such that a corresponding pressure of the ink in the cassette may be substantially maintained at the level of traditional cassettes.

Although the invention has been explained above with reference to particular em- bodiments, it is clear that various variations of the invention are possible within the scope of the appended claims. Particularly, it should be pointed that although reference is made to a standard cassette and that for the main producers, this standard cassette is used irrespective of the brand and type of printer, the skilled person will be able to adapt the standard cassette to any future standard in this area without departing from the inventive principles as explained above. Furthermore, the ink cassettes are at pre¬ sent made from a plastic moulding process, generally from a substantially transparent plastic material, suitable for the task at hand, may also be contemplated within the scope of the present invention.

A specific embodiment of the invention will now be explained with reference to the accompanying drawing, wherein

fig. 1 illustrates a standard ink cassette, fig. 2 illustrates the principle of an ink refill system according to the invention, fig. 3 illustrates a further embodiment of the invention, fig. 4 illustrates an integrated system, fig. 5 illustrates the rear of the system, fig. 6 illustrates an inventive cassette which may be used with the system, and fig. 7 illustrates a system arranged on a printer.

In fig. I₅ a fairly standardised cassette of the type used with printing devices to which the present invention is contemplated is illustrated. The cassette 1 is made from a sub¬ stantially transparent plastic material such that it is easy to recognize both the level of the ink contained therein as well as the colour of the ink. In the present illustration, the cassette is empty. In one end of the cassette 1, an engagement section 2 is provided which will be able to interface with the printing unit. The ink will be led out through communication means 3 provided in this engagement section. At the opposite end, an aperture with a corresponding closure member 4 is provided through which the cas¬ sette may be refilled. These types of cassettes are commonly used in well-known brands of printers and have more or less become a standard for the type of printers for which the present invention is related.

In fig. 2, a continuous ink refill system 5 is illustrated. The system comprises a reser¬ voir 6, and in this particular embodiment, two magnetic valves 7 which are arranged adjacent the bottom of the reservoir 6.

The magnetic valves are by means of electric wires 8 connected to a control box 9. Also the magnetic valves 7 are by means of tubes 10 connected to a refilling tube 11. The control box is by means of further wiring 12 connected to a level sensing means 13 arranged adjacent the filling means 11. The filling means 11 and the level sensor means 13 are arranged in a member 14 which may be fitted into a cassette 1 as illus¬ trated in fig. 1. In advantageous embodiment, the size of the member 14 corresponds to the plug 4 already present in the cassette 1 according to fig. 1.

The reservoir 6 is furthermore provided with a pivotable lid 29 such that easy access may be gained to the interior of the reservoir in order to be able to fill more ink into the reservoir 6.

In the embodiment of the invention illustrated in fig. 2, the system 5 is equipped two magnetic valves 7 and two sets of ink fillers 11 and level sensors 13. It is, however, clear that also embodiments only comprising one magnetic valve and one ink filling tube as well as one level sensor means or more than two are comprised within the in- vention.

The control box 9 is provided with an adequate source of energy, and in cases where communication is desired with an external device, the control box is provided with suitable means for carrying out this communication (not illustrated). The main object of the control box 9, however, is to in response to the input from the level sensor means 13 to open the valves 7 in order to refill ink through the tube 10 and the ink filling pipe 11 into the reservoir 6. Turning to fig. 3, a further advantageous embodiment of the invention is illustrated. In this embodiment, the ink reservoir 6 is placed inside a covering box 15 illustrated by dashed lines. In the figure, the reservoir is partly filled with ink 16. Furthermore, a bracket 17 is provided which is adaptable to be mounted on a printer in the vicinity of the cassettes containing the ink necessary for the printing process. The bracket 17 fur- thermore in this particular embodiment comprises a holder for the covering box 15. The box 15 is removable such that access may be gained to the lid 29 in order to refill the ink reservoir 6. The member 14 in which the sensor means 13 as well as the refill ink tube 11 are arranged is in this embodiment a separate unit which by means of ap¬ propriate connection means 18,19,20,21 may be connected to respectively the control box 9 and the magnetic valve 7.

In order to indicate that a proper connection has been made, a light diode 22 may be provided where the connection means are to be introduced into the system 5. In order to indicate to the user on the outside, further diodes 23,24 may be provided in order to indicate the status of the system, i.e. assure that proper working of the magnetic valve, the level sensor etc. is achieved.

Also on the bottom of the bracket 17, a tray 25 is provided which tray 25 may be pro¬ vided with an absorbent material such that drops or droplets from the connection or during the connection of the ink filling tube 11 and the connection through the mag¬ netic valve 7 are collected and absorbed in this tray and therefore do not stain the inte¬ rior of the casing 15 and thereby minimises the cleaning requirements of the system all together.

Turning to fig. 4, the system according to the invention has been integrated in one sin¬ gle unit. The unit has an engagement section 2 corresponding to the engagement sec¬ tion of the cassette depicted in fig. 1. It is thereby possible to insert the ink refill sys¬ tem directly into the printer without necessitating adding on a system as for example depicted and described with reference to fig. 3. In the system, the reservoir 6 is ar¬ ranged integral with the unit and immediately above the normal reservoir 1 in the cas¬ sette. In the figure, the refill reservoir 6 as well as the cassette reservoir 1 are depicted partly filled with ink 16. The cassette reservoir 1 is connected by thin pipe 27 to the exterior of the unit such that the pressure inside the cassette reservoir 1 may be con¬ trolled. A level sensor 13 is arranged in the cassette reservoir 1 which level sensor 13 is connected to the control box 9 which in turn controls the magnetic valve 7 such that refill of ink may be provided from the ink refill reservoir 6 through the tubing 10 to the reservoir 1 in the cassette.

As the integrated refill system is inserted into the slot provided for the cassette in the printer unit, an interface unit in the printer will engage the corresponding interface unit 27 provided in the integrated refill unit. Li this manner, the integrated unit has pro¬ vided access to the ink 16 in much the same manner as with traditional cassettes for example as depicted in fig. 1. Refilling of the reservoir is provided by means of the opening with corresponding plug 28. A light diode 23 is schematically illustrated in connection with the control box in order to indicate that the control box 9 as is the case with all the embodiments of the invention they may be provided with adequate optical or audible means in order to indicate the status of the system and/or generate the appropriate alarms indicating that for example the refill reservoir is near empty, or that the ink reservoir in the cassette 1 is empty. Furthermore, all the necessary energy supply wiring as well as the details of the control box are outside the scope of the pre¬ sent invention and has therefore not been depicted.

Fig. 5 illustrates a system as illustrated in fig. 3. The casing 15 in this illustration cov¬ ers three sets of two cassettes where appropriate apertures have been provided in the casings in order to be able to see the optical means, for example the diodes 23 indicat¬ ing the status of the system. This is the view a user of the system will normally have in that the casing 15 will cover all the parts as illustrated in figs. 2, 3 or 4.

Also within the scope of the invention, a special cassette 30 as illustrated in fig. 6 is provided. Reference is shortly made to fig 7 wherein a system as illustrated in fig. 3 is arranged on a printer. The reservoirs 6 of the six different colours are visible, and the reservoirs 6 are connected by tubes 10 to the different cassettes 1. The magnetic val¬ ves, control box etc. are covered by the casing 15 which in this embodiment allows a part of the reservoirs 6 to protrude through the casing in order to easily gain informa¬ tion as to the level and colour of ink still present in the reservoir 6. As the reservoirs 6 have a volume such that they will be able to refill the cassettes 1 in order to achieve a substantial uninterrupted printing time, it is possible by providing a cassette 30 as de¬ picted in fig. 6 to further reduce the number of magnetic valves further simplify the control box and also reduce the number of connections from the reservoirs 6 to the cassettes 1 such that the overall performance will be simplified and the risk of failure may be minimised. The cassettes 30 depicted in fig. 6 is generally U-shaped where the distance between the two legs of the U is "a" corresponding to the distance between two adjacent cassettes 1 as illustrated with reference to fig. 7. The bottom of the U 31 connects the two legs 32 of the U such that one large volume is present inside the cas¬ sette 30. Appropriate interface means 27 are provided at the end of the legs 32. Furthermore, the member 14 holding the ink fill tube as well as the sensor means 13 may be inserted in the aperture 33.

Claims

1. A continuous ink refill system for continuously refilling an ink cassette arranged in a printing device, where said refill system comprises an ink reservoir, valve means arranged substantially at the bottom of said reservoir, an ink tube connected to said valve, where the tube comprises means for a liquid tight connection to an ink cassette in a printing device, and that a sensor device is arranged for registering the ink level in the cassette and further that the sensor comprises means for generating control signals for controlling the valve means.

2. System according to claim 1 wherein the valve means is an electrically operated magnetic valve device.

3. System according to claim 1 wherein a control box is provided where the input from the sensor is translated to a control signal for the valve, and optionally that the input may further control one or more diodes and/or alarms and/or generate a status report transmitted to an external device.

4. System according to claim 1 wherein the sensor device and/or the tube is connected by means of a snap coupling, such that the tube and/or the electrical wire may be dis- engaged from the system.

5. System according to claim 1 wherein one or more reservoirs are arranged on a mounting bracket, and that optical means for indicating the status of the system are arranged on the bracket and that the bracket is arranged at a distance from the cassette.

6. System according to any preceding claim characterised in that one or more cassettes are provided, and that each cassette is of double configuration, such that each cassette is generally U shaped and having a height corresponding to a standard cassette, and that at one or both the free ends of the two legs of the U, the cassette is provided with interface means for allowing ink to be communicated between the cassette and the printer head, and that the dimensions of the legs substantially corresponds to the di¬ mensions of a standard cassette, and further that the distance between the legs of the U corresponds to the distance between the interface means arranged in the printer, and further that the volume at the bottom of the U is allowing liquid communication be¬ tween the volumes in the legs of the U.

7. System according to any preceding claim characterised in that one or more cassettes are provided, and that each cassette is integrated with the reservoir, and further that the level sensor, valve, tubing, wiring, control box and optionally other features are inte¬ grated in the cassette, such that the cassette extends upwards and/or rearwards from an engagement section with the printer.