EP1279509B1 - Device for cleaning a printhead of an inkjet printer - Google Patents

Description

Technical area

The invention relates to a device for cleaning a print head of an inkjet printer according to the preamble of claim 1.

State of the art

In addition to printheads from inkjet printers that come as disposable units, there are more and more printheads with replaceable ink cartridges available. As a result, the life of the relatively expensive injection modules with the piezoelectric or thermoelectric transducers, channel structures and nozzle plates can be utilized much better. An example of such a printhead is in EP-A-560 729 described. Because the injection module is thus longer in operation, in particular the nozzle plate tends to foul. Printer manufacturers recommend cleaning the printhead every three months. However, since no corresponding accessories are supplied with the printer for this purpose, this contamination has been remedied by cleaning the nozzle plate from time to time with a damp cloth. However, this carries the risk of damage in itself.

Further, when an ink jet print head is not used for a long time, residual ink dries on the nozzle plate, which can not be eliminated with the conventional cleaning process prescribed in the printer. With the possibility of multiple uses and the need to repeatedly install and remove the printhead to refill or replace the ink tank, the printhead's electrical contacts are contaminated by oxidation, ink, and / or fingerprints. Since the printhead is operated with relatively small pulse voltages, even a slight contamination is sufficient to disturb the function of the printhead.

Out DE 200 12 946 U is a printer-internal service facility known. The print head is pivotally mounted in the printing unit, wherein it is movable in different predetermined angular positions. These angular positions correspond to various service positions such as a lock position, a wiping position, a wiping position and an ink collecting position. The disadvantage is that this service device is coupled to the printer and also requires a relatively large amount of space.

In addition, a prepared and refilled printhead for storage and transport outside the printer must be able to be resealed.

EP-A-0'671'273 discloses a cap for a printhead which can be folded from an open to a closed position. DE-A-196'09'879 describes a storage container for a printhead having a cap of a resilient material to protect the nozzle openings from drying out. EP-A-900'661 shows a storage container for multiple printheads. The storage container has cleaning agents that clean the printheads the same when inserted into the container.

JP 08244247 describes a storage container for a printhead, the container having an absorbent body impregnated with an ink solvent or with water.

Presentation of the invention

It is an object of the invention to provide a cleaning device for the printheads mentioned above, with which the printhead, in particular its nozzle plate and / or the electrical contacts, can be gently cleaned and which also during parking and / or during transport drying out of the ink prevents the nozzles of the nozzle plate.

This object is achieved by a device having the features of patent claim 1.

According to the invention, a holder for receiving the print head is present, in which an absorbent element for cleaning the nozzle plate and / or the electrical contacts is arranged. Furthermore, the holder has a sealing element which seals a nozzle plate of the print head. The holder has at least one movable member, so that it can be switched from a position for parking and / or transport of the print head in a cleaning position for cleaning the nozzle plate.

This ensures that the cleaning of the nozzle plate in a suitable manner, without damaging them, takes place, and that the nozzle plate is protected when drying the printhead outside the printer from drying out.

In first embodiments for cleaning the nozzle plate, the absorbent element is arranged on a movable first carrier, so that the print head remains in the holder for cleaning.

In further embodiments, the holder has a cleaning element for cleaning the electrical contacts, which is arranged on a movable carrier.

In a simple embodiment, the cleaning element for the nozzle plate is designed as a cushion, which can be drizzled with a cleaning liquid. The print head is removed from the holder for cleaning and the nozzle plate is moved over the pad.

Further advantageous embodiments will become apparent from the dependent claims.

Brief description of the figures

Figuren 1 bis 3

Seitenansichten eines ersten Ausführungsbeispiels in verschiedenen Betriebsstellungen, teilweise im Schnitt,

Figur 4

eine Rückansicht,

Figuren 5 und 6

eine zweite Ausführungsform,

Figur 7

eine dritte Ausführungsform,

Figuren 8 bis 12

eine vierte Ausführungsform, und

Figuren 13 und 14

eine fünfte Ausführungsform.

In the following the subject invention will be explained with reference to preferred embodiments, which are illustrated in the accompanying drawings. Show it:

FIGS. 1 to 3

Side views of a first embodiment in different operating positions, partly in section,

FIG. 4

a rear view,

FIGS. 5 and 6

a second embodiment,

FIG. 7

a third embodiment,

FIGS. 8 to 12

a fourth embodiment, and

FIGS. 13 and 14

a fifth embodiment.

Ways to carry out the invention

The device after the FIGS. 1 to 4 has a holder 1, in which a print head 2 is snapped. For this purpose, the holder 1 has two narrow side walls 10 centering in the form of protruding pins 11, in which semicircular recesses 12 of the printhead 2 engage. In the upper region of the holder 1, a resilient latching lug 13 is formed, which is engaged in a latching shoulder 14 of the head 2. The rear wall 15 of the holder 1 has a circular recess 16 which has a rectangular extension 17 at the bottom. From the lateral edges of this extension 17 are from pin 18, are snapped on a little more than half-round recesses 19 a round flap 20. The flap 20 also has a rectangular projection 21. In a recess 22 on the upper side of the flap 20, a sealing lip 23 is inserted with a circumferential elastomeric or elastic bead, wherein the sealing lip 23 with the flip down flap 20 and inserted head 2, the periphery of the nozzle plate 24th of the head 2 airtight concludes. In the example shown here, the sealing lip is designed rectangular. Other shapes are possible.

Because of the accurate positioning of the head by the pins 11, the sealing of the nozzles of the nozzle plate can be ensured over a long time. This position of the flap 20 is suitable therefore, for shipping the printhead and parking it when not in use so that the ink in the nozzles of the nozzle plates 24 does not dry out. In order to prevent the escape of ink from the nozzles of the nozzle plate during transport in the event of severe temperature or pressure changes, an elastomeric plate is expediently inserted into the sealing lip 23 for transport, which bears on the nozzles in a planar and sealing manner. Alternatively, the nozzles can also be closed by means of an adhesive strip.

Below the flap 20, a plate 31 designed as a carrier is inserted on the bottom 30 of the holder 1. The plate 31 is preferably round. It is snapped with two central, downwardly projecting hooks 32 in an opening 33 of an integrally formed on the bottom 30 spring arm 34. In a circular recess 35 of the plate 31, an absorbent element is used for cleaning the nozzle plate. In the example shown here, it is an elastic washer 36 which is slightly wetted with a cleaning fluid. The washer 36 may for example consist of an open-cell, elastomeric foam. In the case of water-soluble inks, the cleaning liquid consists predominantly of water. The disk or the foam body 36 can also consist of two layers of different pore size, wherein only the lower layer wets and the upper layer is dry in the unloaded state. The lower layer thus has the greater capillarity (narrower pores). This variant has the advantage that rapid evaporation of the cleaning liquid is prevented.

For cleaning, the head 2 is first removed from the holder 1, the flap 20 in the position after FIG. 2 folded up and the head 2 inserted again. Now, the plate 31 can be pushed up manually ( FIG. 3 ), where he diametrically opposite the Nozzle plate 24 abuts against a stop 37, so that the plate 31 is exactly parallel to the nozzle plate 24. The movement of the plate 31 may also be limited on the opposite side by stops, so that the disc 36 is pressed against the nozzle plate 24 with a defined pressure. Optionally, the plate 31 can also be easily rotated during cleaning. Suitably, the plate 31 is rotated slightly further between successive cleaning steps. When the disc 36 consists of two layers of different porosity, when compressing during pressing and the upper layer is slightly wetted, resulting in a better cleaning.

With the described device a gentle, yet thorough cleaning of the nozzle plate 24 is made possible. After cleaning, the head 2 is removed, the flap 20 folded down, so that a protruding edge 38 seals on the underside of the flap 20 against an edge 39 of the plate 31, so that the foam body 36 does not dry out. In the lowered position, the edge 40 of an opening 41 of the flap 20 engages behind a latching lug 42 of the holder 1 a.

According to the embodiments FIGS. 5 to 14 Analog parts are provided with the same reference numerals, so that a detailed description of these parts is unnecessary.

In the embodiment according to FIGS. 5 and 6 is dispensed with the flap 20. The carrier or plate 31 is rotatable in steps and locked with locking elements each in one of these rotational positions. The locking elements consist of an integrally formed on the holder 1 spring arm 45 with a notch 46, in which locking cams 47 engage on the outer circumference of the plate 31. The plate 31 is divided into several areas 48. In one of these areas 48, the recess 22 is formed, in which the sealing lip 23 is fixed. In the other areas 48 wetted with cleaning liquid foam plates 49 are used to clean the nozzle plate. Under each of these plates 49, the plate 31 has a through opening 50. A further opening 51 is located in the bottom 30 of the holder 1 below the nozzle plate 24. In the in FIGS. 5 and 6 shown parking and transport position of the plate 31 is the sealing lip 23 below the nozzle plate 24. If these are cleaned, the head 2 is removed from the holder 1, the plate 31 is rotated by one or more steps and the head 2 used again. Now the foam plate in question 49 pressed by the aligned openings 50, 51 against the nozzle plate 24 and these are cleaned with it. In order to prevent the platelets 49 from drying out, a disc, not shown, which seals against its edge 39, may be fastened to the carrier 1 above the plate 31, in which area a sector is recessed below the nozzle plate 24. The transport lock can according to the embodiment according to FIGS. 1 to 3 be supplemented, that is, it may be 20 provided a corresponding flap.

In the embodiment according to FIG. 7 the plate 31 is rotatable in three positions, namely one for shipping, one for parking and one for cleaning the nozzle plate. For pivoting in these positions, a lever 52 is formed on the plate 31. In a first recess 22, the sealing lip 23 is attached. This serves to park the head 2. In a second recess 53, a specially designed for the transport seal 54 is used, for example, the entire surface of the nozzle plate 24 rests and closes the nozzle. In the third recess 55, the foam plate 49 is used for cleaning the nozzle plate.

In the simple embodiment of the FIGS. 8 to 12 the circumferential sealing lip 23 is inserted directly in the bottom 30. The cleaning element is designed as a cushion 36 and used in addition to the sealing lip 23 in a recess 60 of the bottom 30. To clean the nozzle plate 24, the printhead 2 is removed from the holder 1, and a few drops 61 of cleaning liquid are dropped on the pad 36. The cleaning of the nozzle plate 24 by slight pressing and reciprocating on the pad 36 ( FIG. 9 ). If, after a long period of inoperative use, the ink should have dried in the nozzles of the nozzle plate 24, one or two drops of cleaning liquid 61 are introduced into the recess 62 of the sealing element 63 enclosed by the sealing lip 23 ( FIG. 10 ), the printhead 2 is inserted into the holder 1 and turned upside down ( FIG. 11 ). Subsequently, the print head 2 is removed from the holder 1, the nozzle plate 24 is wiped on the pad 36 ( FIG. 12 ) and the printhead is reinstalled in the holder 1 or directly in the printer. The centering on the holder 1 for the printhead 2 may be formed the same as in the embodiments, for example FIGS. 1 to 6 ,

FIGS. 13 and 14 show an embodiment in which in a circular opening 66 of the rear wall 15, a carrier or plate 67 is rotatably inserted. On the front of the plate 67, a cleaning element made of an absorbent material is attached, which is also preferably porous and elastic. In the example shown here, the cleaning element is a disc 68, such as a sponge, mounted analogous to the disc 36 of the first embodiment. The rear side has a handle 69 for manually rotating the plate 67. When the print head 2 is inserted, a flextape on the back of the print head 2 with the connection contacts 70 is pressed lightly against the disk 68. For cleaning The contacts 70 are again dropped a few drops of cleaning liquid on the disc 68, the printhead 2 used and the plate 67 back and forth a few times. In a variant, the carrier is designed as a slide which can be moved back and forth in the vertical direction. Preferably, it is rectangular in shape.

The embodiment according to the FIGS. 13 and 14 can also be used with the mobile carriers according to FIGS. 1 to 7 Mistake. In addition, this embodiment can also be designed as a holder, which does not have a cleaning element integrated in the holder for cleaning the nozzle plate, but comprises only an integrated cleaning element for cleaning the electrical contacts.

With the current possibility of using a printhead several times, the risk of fouling of the nozzle plate and electrical contacts by dust, fibers, dried ink, fingerprints, etc., increases If the printhead is to be stored, for example, because a print head of a different color enters the printer is used, also increases the risk of contamination of nozzle plate and contact points. The present invention solves these problems with a single device. This is very simple and easy to use by anyone. The sealing element 23 effectively protects the nozzles from drying out and from mechanical damage. The sealing element 23 can be used interchangeably, so that the holder can be used for different print heads. The foam body 36 allows a gentle but effective cleaning of the nozzle plate. If the ink is very dry, it is also possible to specifically treat only the nozzle plate. According to the embodiments FIGS. 8 to 13 For example, the cleaning pad 36 can be turned over or reused for heavy use if heavily soiled be replaced with a new cleaning pad. With the polishing pad 68 can be easily eliminated by simply back and forth turning light oxide layers and grease and ink residue on the electrical contacts of the printhead.

LIST OF REFERENCE NUMBERS

1

holder

2

printhead

10

Side wall

11

spigot

12

recess

13

locking lug

14

locking shoulder

15

rear wall

16

recess

17

extension

18

spigot

19

recess

20

flap

21

head Start

22

recess

23

sealing lip

24

nozzle plate

30

ground

31

Carrier, plate

32

hook

33

opening

34

spring arm

35

recess

36

Disc, foam body, cushion

37

attack

38

Projecting edge

39

Edge of the plate

40

Edge of the opening

41

opening

42

Latch of the holder

45

spring arm

46

notch

47

locking cams

48

areas

49

foam rubber

50

opening

51

opening

52

lever

53

Second recess

54

poetry

55

Third recess

60

recess

61

drops

62

recess

63

sealing element

66

opening

67

Carrier, plate

68

disc

69

handle

70

terminals

Claims (9)

1. Apparatus for cleaning a print head of an inkjet printer, comprising a holder (1) having a bottom (30) and an arm (15) with a latching element (13) for latching in the print head (2), a sealing element (23) which is arranged on the holder (1) for sealing a nozzle plate (24) of the print head (2), and an absorbent element (36; 49) which is arranged in the bottom (30) of the holder (1) for cleaning the nozzle plate (24) of the print head (2), characterized in that the holder (1) comprises at least one movable element (20, 31), with the result that it can be changed over from a position for parking and/or transporting the print head (2), in which the nozzle plate is sealed by the sealing element (23), into a cleaning position, in which the absorbent element (36; 49) can be pressed against the nozzle plate (24) of the print head (2).
2. Apparatus according to Claim 1, the sealing element (23) having an annular bead which seals the nozzle plate (24) outside the region of the nozzles.
3. Apparatus according to Claim 1 or 2, the holder (1) having centring elements (11) for centring the print head (2).
4. Apparatus according to Claim 1, a further absorbent element (68) being arranged on the arm (15) and being a polishing disc (68) for cleaning electric contacts (70) of the print head (2), and the polishing disc (68) being mounted on a carrier (67) which is mounted movably in the arm (15) and has a grip element (69) for manual movement.
5. Apparatus according to Claim 1, the movable element being a flap (20) which covers the absorbent element (36) in the parking and transport position and has the sealing element (23) on the upper side, it being possible for the flap (20) to be folded up into a cleaning position, and the absorbent element (36) being fastened on a plate (31) which can be raised up against the nozzle plate (24).
6. Apparatus according to Claim 5, the plate (31) being snapped onto a spring arm (34) which is formed integrally on the holder (1), and a stop (37) for the plate (31) being formed integrally on the holder (1) on that side of the plate (31) which lies diagonally opposite the nozzle plate (24).
7. Apparatus according to Claim 1, the movable element being a plate (31) which is mounted rotatably on the holder (1), on which plate (31) the absorbent element (49) is attached and on which plate (31) the sealing element (23) is attached such that it is offset in the circumferential direction with respect to the absorbent element (49), and the absorbent element (49) being covered by a plate in the parking and/or transport position.
8. Apparatus according to Claim 7, separate sealing elements (23, 54) for the parking and transport position being attached on the plate (31).
9. Apparatus according to one of Claims 1 to 8, the absorbent element (36, 49) being moistened and comprising two layers of different porosity, the lower layer which faces away from the print head having a higher porosity, and only the lower layer being moistened.

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