EP1504905B1 - On the fly ink-jet nozzle cleaning device - Google Patents

Description

Field of the invention

The present invention relates to the field of mail processing and more particularly relates to a device for cleaning the ink ejection nozzles of an ink jet print head of a franking machine for mail items. .

Prior art

Conventionally, the cleaning of ink ejection nozzles of a franking machine is carried out periodically when the print head is removed from the transport path of the mail items and arranged in a maintenance position in which the nozzles ink ejection are subjected to scraper means that rid them of pollutants (dried ink particles, waste paper for example) that they could accumulate during previous impressions. US Pat. Nos. 5,813,326 and 5,883,648 are examples of such a device.

This widespread solution to many models of mail processing machines gives overall satisfaction. However, it still has some disadvantages. First, it requires to stop the printing process periodically except to provide two alternating print heads, as proposed by the applicant in its patent application US2002 / 0040354A1, expensive solution and therefore difficult to envisage on a machine to postage cheaply. Then, depending on the quality of paper used for printing, the moment when the ink ejection nozzles begin to foul varies greatly. In particular, when this paper is of very low quality, the clogging of the ejection nozzles can appear very quickly, for example after 10 impressions, which in practice prohibits any use of a maintenance station even with low processing rates. high.

Object and definition of the invention

The present invention proposes a device for cleaning the ink ejection nozzles which does not require the passage of these nozzles to a maintenance station and which can therefore be used during their operation. An object of the present invention is also to provide a simple and inexpensive device, so as to allow its installation on cheap franking machines.

These objects are achieved by an ink ejection nozzle cleaning device of a postage meter ink jet printhead having scraping means, characterized in that said means comprises a finned wheel. (88a, 38b) disposed in a transport path (28) of the mail items (30) to the right of the ejection nozzles (12a, 12b) and whose rotation is actuated by an article of mail during its advance under the print head (10).

With this configuration, the cleaning of polluted nozzles takes place directly during the printing of mail items. It is therefore no longer necessary to stop the machine for traditional scraping of these nozzles at a maintenance station.

The scraping means, which comprises an optionally motorized finned wheel, is articulated between a scraping position in which the scraping means is disposed in the transport path of the mail items and a rest position in which the scraping means is arranged behind this transport path.

Advantageously, there is provided a cleaning means of said scraping means comprises a scraper which rubs each fin of the impeller.

When said wing wheel is mounted on a pivotable support arm that can move between the scraping position and the rest position, the displacement of said support arm can be controlled according to the number of mail items counted by a position sensor disposed on the way of transportation of mail items. This position sensor is advantageously arranged upstream of said scraping means.

Brief description of the drawings

• la figure 1 est une vue schématique d'un premier mode de réalisation de l'invention,
• la figure 2 est une loupe de la figure 1 dans une variante de réalisation,
• la figure 3 est une loupe d'un deuxième mode de réalisation de l'invention,
• les figures 4, 5 et 6 sont des vues schématiques du deuxième mode de réalisation,
• la figure 7 est une loupe d'un troisième mode de réalisation de l'invention,
• les figures 8 et 9 illustrent en loupe et en détail une variante du mode de réalisation de la figure 7, et
• la figure 10 est une vue partielle d'une machine à affranchir de l'art antérieur au niveau des moyens d'impression.

The features and advantages of the present invention will emerge more clearly from the following description, given by way of non-limiting indication, with reference to the appended drawings in which:

• FIG. 1 is a schematic view of a first embodiment of the invention,
• FIG. 2 is a magnifying glass of FIG. 1 in an alternative embodiment;
• FIG. 3 is a magnifying glass of a second embodiment of the invention,
• Figures 4, 5 and 6 are schematic views of the second embodiment,
• FIG. 7 is a magnifying glass of a third embodiment of the invention,
• FIGS. 8 and 9 illustrate in a magnifying glass and in detail a variant of the embodiment of FIG. 7, and
• Figure 10 is a partial view of a franking machine of the prior art at the printing means.

Detailed description of a preferred embodiment

Figure 10 is a partial view at the printing means of a mail processing machine. The print head 10 which conventionally comprises two printing modules 12, 14 offset in a direction perpendicular to the advancing direction D of the mail items is mounted between two sets of drive rollers, a first set of two rollers Upstream 16, 18 superimposed, one of which, preferably the upper roller 16, is motorized and a second series of two downstream rollers 20, 22 superimposed also one of which, preferably the upper roller 20, is motorized. At the level of the printing means, an upper fixed plate 24 and a lower mobile plate 26 (also called mobile ski) define a path 28 for transporting the mail articles 30. These plates are of course perforated to the right of the ejection nozzles of ink 12A, 14A of each print module. The reference 32 illustrates one of the corresponding openings (the second 34 is behind the cutting plane due to the shift of the two modules).

In mail processing machines of the prior art, the print head 10 is movable and can take two positions, a printing position in which the printing of a postal imprint is possible and a rest position or maintenance in which the print head is set back from the transport path 28 at a maintenance station to allow cleaning of the ink ejection nozzles, thus prohibiting any impression of a postal impression.

According to the invention, and as illustrated in the first embodiment of FIG. 1, the print head 10 is now fixed in the printing position and the cleaning of the ink ejection nozzles is carried out directly in this position, ie in the very course of the printing process.

To do this, there is provided scraper means disposed in the path 28 for transporting mail items to the right of the ink ejection nozzles 12A, 14A and actuated by a mail item 30 when it is advanced under these nozzles . More specifically, this scraping means comprises two finned wheels 38A, 38B each provided with at least one fin or blade and arranged in line with a row of nozzles 12A, 12B of a given printing module, in the opening made in the fixed plates 24 and mobile 26, and whose rotation is controlled by the advance of a mail piece. The impeller 38A, 38B being fixed, ie integral with the mail processing machine body, there is provided a light 26A, 26B in the fixed plate 26 so as to allow the displacement of this plate according to the thickness of the mail to print. Of course, each fin combines elasticity and rigidity for effective cleaning without nozzle spoilage.

In order to guarantee that the efficiency of the scraping means is maintained, it co-operates with an automatic blade cleaning means. polluted by the debris from the ink ejection nozzles, formed of a scraper 40A, 40B fixed, ie integral with the mail processing machine body, and on which will rub one after the other the blades of the finned wheels 38A, 38B.

FIG. 2 illustrates an alternative embodiment of FIG. 1 in which the vane wheel 38A, 38B is motorized by a motor 40A, 40B so that scraping of the ejection nozzles can be carried out also between the mail items, or even even in the absence of mail items.

A second embodiment of the invention is illustrated in FIGS. 3 to 6. In this embodiment, each wheel provided with at least one fin or blade is mounted on a support arm 44A, 44B pivoting about an axis of articulation 46A, 46B secured to the movable plate 26, against an elastic means, for example a spring 48A, 48B, integral with the support arm at one end and the movable plate at its other end. This spring mounting allows cleaning the nozzles with optimal application stress.

The support arm can move between a scraping position (corresponding to the position of the first embodiment) and a rest position set back from the transport path (preferably retracted under this path and which can be optionally also disengaged from the sputtering zone of the nozzles) under the action of a control means, for example a motor or an electromagnet 50A, 50B whose motor axis or the corresponding control rod 52A, 52b is connected to the associated support arm. If necessary, and according to the configuration of the mail processing machine, a kinematics with levers and pulleys (not shown) can be provided between this control means and the finned wheels. The control means is actuated from a processing means 54 according to various parameters including the number of mail items counted by a position sensor, of the tilt lever type 56, disposed on the article transport path. of mail upstream of the scraping means and actuated by the front of each mail item. This number of mail items can be set according to the type of paper used or any other consideration, for example the country of installation of the machine. Thus, in this embodiment, the scraping of the nozzles is not performed when printing each mail item but after the passage of a given number of these items.

In order to guarantee optimum efficiency by means of scraping, and as previously, this latter cooperates in its rest position with an automatic cleaning means for the polluted fins formed of the fixed scraper 40A, 40B integral with the body of the machine and on which are going to rub one after the other the blades of the finned wheels 38A, 38B under the effect of the motorization of the wheel 42A, 42B. The cleaning can be synchronized or not with the return of the support arm in its rest position. Thus, for example, the scraping of the nozzles can be done every 10 impressions but the cleaning of the fins (thus the launch of the motor 42A, 42B) only every 100 impressions.

FIG. 7 illustrates a third embodiment of the invention in which the hinge axis 46A, 46B of the support arm 44A, 44B and the control means 50A, 50B are no longer fixed on the mobile platform but are fixed directly on the body of the mail processing machine. With this advantageous embodiment, the motor control is simplified because it is no longer necessary to compensate for the displacement of the movable plate 26, the distance between the impeller and the nozzles is now fixed.

An alternative embodiment of Figure 7 is illustrated in Figure 8. In this embodiment, the control means 50A, 50B is disposed directly on the hinge axis 46A, 46B which further supports the resilient means 48A, 48B. This results in a more compact design which can then be easily integrated into existing machines without major structural changes.

Of course, the present invention can not be limited to the figures illustrated only and the skilled person will be able to complete without demonstrating inventive step. For example, to promote evacuation graded particles of dried ink and paper while significantly reducing the scraping forces exerted on the nozzles, the impeller can have a shape of forest (or worm), each helical cutting edge corresponding to a scraping edge of a pale. Similarly, if the invention has been illustrated with a two-module print head, the use of a single module is equally conceivable.

Claims (8)

1. A device for cleaning the ink ejection nozzles of an inkjet printer head of a franking machine comprising a scraping means, characterised in that said means comprises a vaned wheel (38A, 38B) intended to be arranged in a path of travel (28) of the mail items (30) opposite the ink ejection nozzles (12A, 12B) and whose rotation is actuated by a mail item as it advances beneath the printer head (10).
2. The cleaning device according to claim 1, characterised in that said vaned wheel is articulated between a position of scraping in which the vaned wheel is arranged in the path of travel of the mail items of the franking machine, and a position of rest in which the vaned wheel is withdrawn from this path of travel.
3. The cleaning device according to claim 1 or claim 2, characterised in that it further comprises a means for cleaning said vaned wheel.
4. The cleaning device according to claim 3, characterised in that said cleaning means comprises a scraper (40A, 40B) which rubs each vane of the vaned wheel.
5. The cleaning device according to claim 2, characterised in that said vaned wheel is mounted on a pivoting support arm (44A, 44B) that may move between the position of scraping and the position of rest.
6. The cleaning device according to claim 5, characterised in that the displacement of said support arm is controlled as a function of the number of mail items counted by a position sensor (56) arranged on the path of travel of the mail items.
7. The cleaning device according to claim 6, characterised in that said position sensor is arranged upstream of said vaned wheels.
8. The cleaning device according to claim 5, characterised in that said vaned wheel is motorized (42A, 42B).

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