NL2022196B1 - Printer - Google Patents

Abstract

The present invention relates to a printer comprising a first printing region and a second printing region distinct from the first printing region, wherein the second printing region comprises a print medium for performing a nozzle failure detection procedure.

Description

P3968NLOO 1

PRINTER

FIELD OF THE INVENTION The present invention relates to an inkjet printer, in particular a flatbed inkjet printer.

BACKGROUND ART Flatbed inkjet printers are known in the art, for example the Arizona series of Océ Technologies B.V. In such printers a nozzle check print or test print is required to check the status of the nozzles of the print head, i.e. a Nozzle Failure Detection (NFD) print. Such test prints will usually be made on the print media that is loaded in the printer. In a flatbed printer normally the NFD print needs to be made in the main printing region on the (edges) of the medium. This NFD print may be hard to remove (especially in rigids). A solution presented in the prior art may be to use a separate medium for performing NFD. The productivity of the printer is hence reduced and (in most cases) relatively expensive print substrates are wasted.

It is an object of the present invention to solve or at least mitigate the above disclosed disadvantages.

SUMMARY OF THE INVENTION The object is at least partly achieved by providing a printer comprising a first printing region and a second printing region distinct from the first printing region, wherein the second printing region comprises a print medium for performing a nozzle failure detection procedure.

In the first printing region a print substrate is arranged onto which an image is to be printed. The print medium arranged in the second printing region for performing a nozzle failure detection procedure is separate from said print substrate, hence nozzle status can be tested during a print job and without wasting expensive print substrates.

In an embodiment, the print medium comprised in the second printing region comprises a material that can be easily cleaned, e.g. a (flexible) non-sticking print medium or a glass plate. In the context of the present invention a non-sticking print medium is defined as a medium onto which an image can be printed with a (very) low adhesion of ink to the medium, such that the medium can be easily cleaned and reused. Therefore,

P3968NLOO 2 a non-sticking medium may also be termed a low adhesion medium. The test image does not need to show a strong adhesion to the surface of the print medium, as long as the image can be properly cured (e.g. by drying, UV-curing, etc.), scanned and analyzed.

Nozzle failure detection prints can be made onto the glass plate. After use the ink needs to be removed from the glass plate. This can be done by a scraper. Therefore, in an embodiment, the printer further comprises an integrated scraper to remove the printed image from the non-sticking print medium or glass plate.

In an embodiment, the print medium comprised in the second printing region comprises a medium that can be easily removed, e.g. a disposable medium, for example a stack of Post-ItTM sheet(s). The advantage of using such a disposable medium is that it can be easily removed and refreshed when used.

In an embodiment, the printer comprises a recess with a height adjustable tray provided in the second printing region for holding a stack of the disposable medium, wherein the height adjustable tray can be (automatically) displaced within the recess in order to adjust to the height of the stack positioned on the tray. The height adjustable tray may comprise a spring-loaded platform onto which the stack of the disposable medium is positioned, the position of the spring-loaded platform automatically adjusts to the height of the stack of disposable medium (due to its weight} and hence (automatically) provides a constant print gap (i.e. distance between print medium and nozzles). Alternatively, the height adjustable tray may be actively steered by actuators comprised in the adjustable tray and arranged for height adjustment of the tray.

In an embodiment, the second printing region is arranged next to the first printing region in such a way that during each printing swath a test print can be made without going to a maintenance position. A flat bed printer comprises a table onto which a print substrate can be arranged, a gantry beam that moves in a first direction across the table (and hence across the print substrate arranged thereon) and a print carriage comprising at least one print head, the print carriage moving along the gantry beam in a second direction substantially perpendicular to the first direction. In a printing mode, the print carriage moves in the so called scanning direction. A complete scanning movement is termed a swath. During a swath, a part of the image corresponding to the position of the swath on the print substrate is printed. After a swath has been printed, the gantry moves to a position corresponding to the next swath, corresponding to another part of the image to be printed.

P3968NLOO 3 In a further embodiment the disposable medium comprises a paper tape which is arranged in the second printing region alongside the first printing region, parallel to the first direction, wherein the paper tape is wound on a first roller and the leading end of the tape is attached to a second roller, both rollers arranged at opposite ends of the table, such that the paper tape arranged in the second printing region can be refreshed by activating the second roller, hence moving the paper tape in a direction substantially parallel to the first direction. The advantage is that the disposable medium can be automatically refreshed. In an embodiment the printer further comprises an integrated optical sensor and a controller to analyze a printed image produced with the nozzle failure detection procedure. This embodiment has the advantage that the test print can be scanned an analyzed in real-time. Defective nozzles can be compensated for on the fly (e.g. next swath). In the embodiments wherein the print medium comprises a disposable print medium or a glass plate, the optical sensor can be arranged either on the print head carriage or the gantry beam. In the embodiment wherein the print medium comprised in the second printing region comprises a glass plate, the optical sensor can be arranged to be directed towards the non-printed side of the glass plate. The additional advantage of this embodiment, is that the test print can be automatically detected during printing.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given herein below and accompanying schematical drawings which are given by way of illustration only and are not limitative of the invention, and wherein: Fig.1 schematically shows a flatbed printer Fig. 2A schematically shows a top view flatbed printer comprising a first printing region and a second printing region in accordance with an embodiment of the present invention. Fig. 2B schematically shows a glass plate as a substrate in accordance with an embodiment of the present invention. Fig. 2C schematically shows a recess and spring loaded tray for holding a stack of

P3968NLOO 4 disposable media in accordance with an embodiment of the present invention. Fig 3A schematically shows a top view of a flatbed printer comprising a first printing region and a second printing region in accordance with an embodiment of the present invention.

Fig 3B schematically shows a front view of a flatbed printer shown in Fig 3A.

DETAILED DESCRIPTION Fig. 1is a print system 5 comprising a number of workstations 8B, 8C, which may be personal computers or other devices for preparing image data for prints to be printed. These workstations have access to a network N for transferring print jobs comprising the image data to a print controller 8A that is configured to receive the print jobs for prints and derive pass images. The print controller 8A may be part of the print system 5 connected to a control unit of the print system 5 via a connection 6. The print system 5 further comprises a print head 2 attached to an armature 7 for applying colorants, for example cyan (C), magenta (M), yellow (Y), black (K) and white (W) colorant, or varnish to pieces 9, 9A of flat print media placed on a flatbed surface 1 in order to obtain a printed image. The armature 7 may be a gantry above the flat bed surface 1 as shown in Fig. 1 or a robot arm (not shown} moving in a plurality of directions over the flat bed surface 1. The flatbed surface 1 is the surface of the flatbed which is at least partially printable by the print head 2. The pieces of media may be so small that they are completely placed on the flatbed surface 1, but a piece of media which is larger than the flatbed surface, in which case an image which is going to cover the whole piece of media must be printed into a plurality of parts of the image, is not excluded. A first piece 9A has already been printed upon, while the other pieces 91, 92 are not provided with any recording material yet. The print head 2 reciprocally scans the flatbed surface 1 in the second direction X along a gantry 7 perpendicular to a first direction Y of the gantry 7 over the flatbed surface 1 along guiding parts 10. During printing of an image on the piece 9, 9A of media the piece 91, 92, 9A of media is not moved on the flatbed surface

1. This way of working is advantageous for rigid print media. A print head which is as wide as the flatbed surface may also be envisaged within the scope of the invention. Such a print head may be moveable in at least one direction over the flatbed surface 1. The piece of media 9A may have a thickness of 10 mm, while the pieces of media 91,

P3968NLOO 92 may have a thickness of 20 mm. Fig. 2A shows a top view flatbed printer comprising a first printing region 20 and a second printing region 21 in accordance with an embodiment of the present invention. 5 The size of the second printing region 21 may be designed as desired as is indicated with the dotted line, as long as the second printing region 21 is distinct from the first printing region 20. A printing substrate may be arranged in first printing region 20 on the flat bed surface. In operation, a test print is made by moving the gantry 7 and the print head carriage 30 comprising at least one print head 2 towards the second printing region 21 and printing a test pattern onto the print medium arranged in the second printing region 21. Fig. 2B shows a recess 40 which is provided in the second printing region 21 and which is covered by a glass plate 41 as a substrate in accordance with an embodiment of the present invention. Fig. 2B also schematically shows the print head carriage 30 (when located above the second printing region). The distance between a nozzle surface (not shown) of the print heads arranged on the print head carriage 30 and the glass plate 41 defines a print gap, indicated by double arrow 50. With this arrangement a test pattern can be printed onto the glass plate. Optionally a scanning device 60 may be present arranged for scanning the test print for further analysis. In this particular embodiment the scanning device is arranged beneath the glass plate and scans the image from the opposite side of the glass plate {opposite from the side onto which the image is printed). Alternatively, a scanning device may be arranged on the print head carriage or the gantry. In such configurations, the image is scanned from the same side it is printed on.

Optionally (not shown in Fig. 2B) a scraper may be arranged for removing the fixed ink layer from the glass plate 41. Fig. 2C shows a recess 40’ and spring loaded tray 42 for holding a stack of disposable media 43 in accordance with an embodiment of the present invention. Springs 44 and 45 support tray 42 onto which a stack of disposable media 43 is arranged. The spring loaded tray is designed such that the distance between the top sheet 43’ of the stack of disposable media 43 and the nozzle surface of the print heads arranged on the print head carriage 30 remains constant, also after removing the top sheet of the stack after use. Alternatively, tray 42 may be equipped with actuators which are configured to maintain a constant print gap 50.

P3968NLOO 6 Fig 3A shows a top view of a flatbed printer comprising a first printing region 20 and a second printing region 27’ in accordance with an embodiment of the present invention. The second printing region 21’ is arranged to extend in a direction parallel to the gantry movement direction, indicated with arrow 51 (and hence perpendicular to the scanning direction, indicated with arrow 52). In this arrangement, a test pattern can be printed before or after every pass of the print head carriage (swath). In this embodiment a scanning device 61 is arranged in the gantry 7. In operation, test prints can be made and scanned during a print job, without the necessity to move to a maintenance position first. Therefore, with this arrangement the print productivity is further improved.

Fig 3B shows a front view (direction indicated with arrow A in Fig. 3A) of a flatbed printer comprising a second printing region 21’ which in this example comprises a set of rollers 70 and 71 and an endless belt 72 made of a material to which cured ink does not stick, e.g. teflonTM. After a print job, the endless belt 72 is advanced by rollers 70 and 71 in order to refresh the print surface in the second print region. A scraper 73 is arranged to remove the printed test patterns.

Test patterns as such are known from the art and will not be further explained here. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Specific structural and functional details are not to be interpreted as limiting, but merely as a basis for the claims and as a teaching for one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. In particular, features presented and described in separate dependent claims may be applied in combination, and any advantageous combination of such claims is herewith disclosed.

The terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (ie. open language). The term coupled, as used herein, is defined as connected, although not necessarily directly.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in

P3968NLO0O 7 the art are intended to be included within the scope of the following claims.

P3968NLO0O 8 Embodiments 1) Printer comprising a first printing region and a second printing region distinct from the first printing region, wherein the second printing region comprises a print medium for performing a nozzle failure detection procedure.

2) Printer according to claim 1, wherein the print medium comprised in the second printing region comprises a non-sticking print medium or a glass plate.

3) Printer according to claim 1, wherein the print medium comprised in the second printing region comprises a disposable medium. 4) Printer according to claim 3, wherein the printer comprises an adjustable tray arranged in a recess provided in the second printing region for holding a stack of the disposable medium, wherein the tray automatically adjusts to the stack positioned therein. 5) Printer according to any one of claims 1-4, wherein the printer further comprises an integrated optical sensor and a controller to analyze a printed image produced with the nozzle failure detection procedure. 8) Printer according to claim 2, wherein the printer further comprises an integrated scraper to remove the printed image from the non-sticking print medium or the glass plate.

Claims (6)

1. P3968NLO0O 9 Conclusies 1) Printer omvattende een eerste print zone en een tweede print zone apart van de eerste print zone, met het kenmerk dat de tweede print zone een print medium omvat voor het uitvoeren van een nozzle faal detectie procedure.
2. 2) Printer volgens conclusie 1, met het kenmerk dat het print medium in de tweede print zone een niet-hechtend medium of een glasplaat is.
3. 3) Printer volgens conclusie 1, met het kenmerk dat het print medium in de tweede print zone een wegwerp print medium is.
4. 4) Printer volgens conclusie 3, met het kenmerk dat de printer een in hoogte verstelbaar plateau bevat dat is gesitueerd in een uitsparing in de tweede print zone voor het herbergen van een stapel wegwerp print media, waarin het plateau zich automatisch aanpast aan de stapel wegwerp print media dat het herbergt.
5. 5) Printer volgens een van de conclusies 1-4, met het kenmerk dat de printer een geïntegreerde optische sensor omvat en een aansturing voor analyse van een geprint beeld vervaardigd met de nozzle faal detectie procedure.
6. 6) Printer volgens conclusie 2, met het kenmerk dat de printer een geïntegreerde schraper omvat voor het verwijderen van het geprinte beeld van het niet-hechtend medium of de glasplaat.