WO1997007980A1

WO1997007980A1 - A method for cleaning an ink cartridge suitable for ink jet printing devices and also a device suitable for carrying out such a method

Info

Publication number: WO1997007980A1
Application number: PCT/NL1996/000335
Authority: WO
Inventors: Hubertus Antonius Johannes Smets
Original assignee: Smets Hubertus Antonius Johann
Priority date: 1995-08-28
Filing date: 1996-08-23
Publication date: 1997-03-06
Also published as: NL1001076C2; AU6757396A

Abstract

The invention relates to a method and a device for cleaning an ink cartridge suitable for ink jet printing devices, which is provided with a plurality of ink outlet openings. To clean, steam is supplied, whether or not intermittently, through the ink outlet openings. Steam is for example introduced into the ink cartridge through a first group of ink outlet openings and discharged from the ink cartridge through a second group of ink outlet openings. The device comprises a steam supply means and a screening plate which can be connected to said steam supply means.

Description

A method for cleaning an ink cartridge suitable for ink jet printing devices and also a device suitable for carrying out such a method.

The invention relates to a method for cleaning an ink cartridge suitable for ink jet printing devices, which is provided with a plurality of ink outlet openings.

A cartridge of this type which is suitable for being used in an ink jet printing device, such as for example the cartridge marketed by Hewlett Packard under type designation HP 51626A, is provided with a plurality of outlet openings, through each of which an ink jet or ink drops can be delivered during use of the cartridge in an ink jet printing device. The users of such ink cartridges appreciate having a possibility to refill the cartridge with ink, on the one hand in connection with the high cost of purchasing new cartridges and on the other hand in view of the environmental pollution caused by disposing of the cartridge after using it only once.

Generally the refilling of an ink cartridge in order to make it possible to use it more than once does not present any problems, but problems may occur when the ink outlet opening(s) has (have) clogged up. As a result of crystallisation and drying of ink blockages may form in the ink outlet openings. Such blockages may also be caused when printing with the inkjet printing device is continued whilst there is insufficient or no ink present in the cartridge, which may lead to burning of ink residue in and near the ink outlet openings. In order to remove such blockages of one or more ink outlet openings it has already been proposed to clean the ink cartridge by immersing it in water or in a cleaning fluid (which burdens the environment) prior to refilling it with ink. Tests have shown that when the ink cartridge is immersed, partially or entirely, in a (possibly hot) fluid, whereby ultrasonic vibrations may be used, glued connections, electric contacts and other parts of the ink cartridge, for example parts made of plastic material, may be damaged as a result of the glued connections being affected, short-circuiting caused by fluid residue remaining behind between the electric contacts and plasticizing of the parts made of plastic material . Another drawback of cleaning with a special cleaning fluid is the fact that residue of the cleaning fluid will inevitably remain behind in the interior part of the ink chamber of the ink cartridge, which residue will affect the surface tension and composition of the ink, which may eventually lead to a poor printing result. Consequently the percentage of rejects is high, ± 20 - 30%, when cleaning methods of this type are used, because the electronic components are damaged or because not all ink openings are cleaned.

The object of the invention is to provide a method by means of which ink cartridges can be cleaned quickly and effectively in an ecologically sound manner. According to the invention this may be achieved in that steam is passed through said ink outlet openings.

By supplying steam under a pressure of for example ± 3 bar it is possible to effect a thorough cleaning of the ink outlet openings, because burnt ink, ink residue and crystallized ink parts are dissolved in the steam. It has become apparent that when cleaning with steam is carried out in this manner, the temperature of the ink cartridge only increases locally at the ink outlet openings, without the ink cartridge or parts housed within the ink cartridge sustaining any damage thereby. Any condensed steam remaining behind in the ink cartridge will mix with the water of the ink and will not have an adverse effect on the composition of the ink thereby.

An advantageous embodiment of the method is obtained when steam is introduced into the ink cartridge through a first group of ink outlet openings and discharged from the ink cartridge through a second group of ink outlet openings.

Advantageously the place where the steam is introduced into the ink cartridge is changed during the cleaning process, so that steam is alternately introduced and discharged through ink outlet openings.

According to the invention the introduction of steam into the ink cartridge may furthermore be effected in a simple and efficient manner in that a screening plate provided with a slot is placed over the ink outlet openings, in such a manner that a steam passage provided in said screening plate is positioned opposite a first group of ink outlet openings, after which steam is supplied to the respective ink outlet openings through said steam passage. At least part of the steam being supplied will thereby flow into the ink cartridge through the ink outlet openings positioned opposite said steam passage and part of the steam will flow out through the slot and over the mouths of the further ink outlet openings. This steam flowing out through the slot exerts a suction force on the steam introduced into the ink cartridge, as a result of which the steam introduced into the ink cartridge is expelled from the ink cartridge under the influence of the pressure within the ink cartridge and the sucking effect of the steam flowing through the slot.

According to the invention it is preferred to fill the ink cartridge with ink prior to cleaning, leaving open an air-filled space near said ink outlet openings. As a result of this the space in the ink cartridge which receives the steam can be kept small, which has an advantageous effect on the amount of steam used for cleaning the ink cartridge.

Another aspect of the invention relates to a device which is suitable for carrying out the method according to the invention.

According to the invention said device is provided with a steam supply means and with a screening plate which can be connected to said steam supply means. When using a device of this type vulnerable parts of the ink cartridge can be screened from the hot steam used during operation by means of said screening plate.

The invention will be explained in more detail below with reference to the accompanying Figures.

Figure 1 is a schematic side view of a possible embodiment of an ink cartridge. Figure 2 is a larger-scale sectional view of a wall part of the ink cartridge shown in Figure 1, which part is surrounded by circle 11 in Figure 1.

Figure 3 is a perspective view of a screening plate of a device according to the invention. Figure 4 is a sectional view of the screening plate along line IV-IV in Figure 3, showing said screening plate in a position in which it is placed on the wall part illustrated in Figure 2.

Figure 5 is a sectional view of Figure 4, along line V-V in Figure 4. Figures 6A-6D show the ink cartridge during various stages of the cleaning of the ink cartridge in accordance with the method of the invention.

Figure 1 schematically shows a side view of an ink cartridge 1 of type No. HP51626A marketed by Hewlett Packard. Although the invention will be explained in more detail hereafter on the basis of this type of ink cartridge, it will be apparent that the invention can also be used with ink cartridges of a different construction.

The ink cartridge 1 comprises a housing 2, which functions as a reservoir for the ink, and which includes air pockets (not shown). A plurality of ink outlet openings 4 are formed in a wall part 3 of ink cartridge 1 (Figures 2, 4, 5), said ink outlet openings in the present embodiment being arranged in two rows extending parallel to each other, as will be apparent from Figure 5. The openings 4 are located between two ribs 5 provided on wall part 3, which extend parallel to said rows of openings. The ink cartridge is furthermore conventionally provided with an aeration opening 6 located near wall part 3, a closable ink inlet opening 7 and an air inlet opening 8 for supplying air to air pockets present within the ink cartridge.

The construction and the use of ink cartridges of this type in inkjet printing devices are generally known, inter alia from relevant publications by the firm of Hewlett Packard, so that all this may be considered to be known per se and need not be explained in more detail herein.

A screening plate 9 shown in Figures 3 - 5 is used to carry out the method according to the invention, which screening plate may for example be made of a metal or of plastic material . Screening plate 9 is provided with three slots 10-12, which extend parallel to each other and which are open at one side of the screening plate 9. As will be apparent in particular from Figures 4 and 5, the construction is thereby such that when the screening plate 9 is placed on the outer side of wall part 3, the two ribs 5 present on wall part 3 are received in the outer grooves 10 and 12 and that groove 11 will thereby be positioned opposite the part of wall part 3 in which the openings 4 are formed.

Groove 11 is in open communication with a passage or passages 13 formed in screening plate 9. Plate 9 may also form part of a device (not shown) which is provided with a steam supply means to be connected to passage 13, via which steam under a pressure of for example 3 bar may be supplied.

As will be apparent from Figure 5, the dimensions of passage 13 are thereby such that when screening plate 3 is present on wall part 3 of the ink cartridge a number of the openings 4 will be positioned opposite passage 13, seen in the longitudinal direction of passage 13, whilst the remaining openings 4 will be positioned beside said passage 13, seen in the longitudinal direction of passage 13. The width of slot 11 is slightly greater than the distance between the ink outlet openings 4 in the two rows that are spaced furthest apart, whilst the depth of said slot 13 may be ± 0.1 mm. Furthermore said slot 11 is open at at least one end.

The method according to the invention will now be explained in more detail with reference to Figures 6A-6D. An ink cartridge 1, whose contents are used up and which is to be refilled, will first be examined in order to verify whether the conducting parts still function properly and in order to make sure that the ink cartridge is free from damage, for example to make sure that the means bounding the air pockets inside the housing 2 of the ink cartridge are still intact.

Furthermore the ink which is still present in the ink cartridge may be drawn from the ink cartridge via ink inlet opening 7, if necessary. Then new ink will be introduced into the ink cartridge 1 via ink inlet opening 7 until ink cartridge is substantially completely filled. All this is a usual procedure, which is known per se and which is inter alia disclosed in EP-A-0 568 144, so that such a method for refilling an ink cartridge with ink need not be described in more detail herein.

Then the ink cartridge will be disposed in such a manner that the above-described wall part 3 of ink cartridge 1 is positioned near the upper side of the ink cartridge and extends at an angle of ± 85° with respect to the horizontal, as is illustrated in Figure 6A. As a result of this air which is still present in the ink cartridge will collect under wall part 3 in the part of ink cartridge 1 indicated at 14. Then screening plate 9 is placed on wall part 3 in the manner indicated in Figures 4 and 5, as is also indicated in Figure 6A. Subsequently steam under a pressure of for example ± 3 bar is supplied to the slot provided in screening plate 9 via passage 13, as is indicated by arrow A in Figure 6A. Said supplying of steam may take place continuously or intermittently. Part of the steam supplied in this manner will flow into the interior of cartridge 1 via a group of ink outlet openings 4 being in line with steam passage 13, seen in Figure 15. Another part of said steam supplied to slot 11 will flow out of said slot along the outer side of wall part 3, as is indicated by means of arrows B in Figure 6A. This steam flowing out in the direction according to arrow B generates a certain sub-atmospheric pressure at the mouths of ink outlet openings 4 that are not overlapped by passage 13. Said sub-atmospheric pressure and the pressure in space 14 together cause the steam supplied to space 14 to be discharged via the openings 4 that are not overlapped by passage 13, seen in Figure 5. It will be possible to effect an effective cleaning of the openings 4 with the steam flowing through openings 4. It is preferred to move ink cartridge 1 and screening plate 9 in the direction of arrows B relative to each other while steam is being supplied, so that steam will alternately flow into the interior of ink cartridge 1 and out of said ink cartridge 1 through particular ink outlet openings. The steam flowing through the interior of may also clean parts of the ink cartridge present in the interior of said cartridge.

After the intended cleaning has been completed, screening plate 9 or the device comprising said screening plate are removed, leaving cartridge 1, as is shown in Figure 6B. Then opening 6 is closed and air is introduced into the air pockets present in the interior of ink cartridge 1 through openings 8, causing air present in space 14 to be discharged through ink outlet openings 4, after which a small part of the ink present in ink cartridge 1 is driven through ink outlet openings 4 (Figure 6C). This may also be effected by generating a sub-atmospheric pressure at the mouths of ink outlet openings 4. Said ink is slightly heated, because the temperature of the part of the wall part 3 surrounding outlet openings 4 is comparatively high. Said slightly heated ink will effect an additional cleaning of ink outlet openings 4, insofar as this should still be necessary. An additional effect is that the wall part surrounding openings 4 is cooled in this manner. Furthermore the outside of ink cartridge 1 may be cleaned by means of a steam jet, if necessary.

The contaminated steam discharged when the above- described method is being carried out may be caught and condensed, after which the liquid thus obtained may be evaporated, leaving behind a comparatively small amount of dry matter containing ink residue, which may be processed as chemical waste.

The ink cartridge filled and cleaned in this manner may furthermore be tested and be placed in a holder 15 known from EP-A-0 568 124, after having sealed the appropriate openings present in ink cartridge 1 with suitable, removable means.

The above-described embodiment of screening plate 9 allow said screening plate to be supported on a large portion of wall part 3 during use, as a result of which the surface pressure between screening part 9 and wall part 3 may be kept comparatively low when carrying out the method, thus preventing electric contacts (not shown) associated with wall part 3 and the like from being damaged. The above-described embodiments of the screening plate furthermore prevent the ribs 5, which have a sealing function during use of the ink cartridge, from coming into contact with the hot steam.

Also depending on the type of ink cartridge it will be possible to supply the steam in a different manner, for example by means of a jet pipe or the like, which is passed along the mouths of the ink outlet openings, whether or not with some spacing between said jet pipe and said ink outlet openings.

Furthermore it is possible to carry out said cleaning prior to filling the ink cartridge with ink.

Claims

1. A method for cleaning an ink cartridge suitable for ink jet printing devices, which is provided with a plurality of ink outlet openings, characterized in that steam is passed through said ink outlet openings.

2. A method according to claim 1, characterized in that said steam is supplied intermittently.

3. A method according to claim 1 or 2, characterized in that steam is introduced into the ink cartridge through a first group of ink outlet openings and discharged from the ink cartridge through a second group of ink outlet openings.

4. A method according to claim 3, characterized in that steam is alternately introduced into the ink cartridge and discharged from the ink cartridge through certain ink outlet openings.

5. A method according to any one of the preceding claims, characterized in that a screening plate provided with a slot which is open at at least one end is placed over said ink outlet openings, in such a manner that a steam passage provided in said screening plate is positioned opposite a first group of ink outlet openings and that steam is then supplied to said slot through said steam passage, all this in such a manner that part of the steam is driven through the ink outlet openings positioned opposite said steam passage and that another part of the steam will flow through the slot over the mouths of said second group of ink outlet openings.

6. A method according to claim 5, characterized in that the steam passage and the ink outlet openings arranged in at least one row are moved relative to each other in the longitudinal direction of said row while steam is being supplied.

7. A method according to any one of the preceding claims, characterized in that the ink cartridge is filled with ink prior to cleaning said ink outlet openings, leaving open an air-filled space near said ink outlet openings.

8. A device suitable for carrying out amethod according to any one of the preceding claims, characterized in that said device is provided with a steam supply means and with a screening plate which can be connected to said steam supply means.

9. A device according to claim 8, characterized in that said screening plate is provided with a slot which is open at one side face of said screening plate and at at least one end, and with a steam passage opening into said slot, which can be connected to said steam supply means.