When printing on a print medium, e.g. a media roll, after completing printing of an image the printed medium portion including the printed image may be separated from the rest of the print medium. This can be done using a cutter device which is separate from a printer or integrated with or attached to a printer. To obtain a correct cutting line position, the print medium may be positioned for cutting after printing the image, and then repositioned for printing a next image. Cutting may delay the printing process.
For the purpose of illustration, certain examples will now be described with reference to the accompanying drawings, in which:
In the following detailed description, reference is made to the accompanying drawings. The examples in the description and drawings should be considered illustrative and are not to be considered as limiting to the specific example or element described. Multiple examples may be derived from the following description and/or drawings through modification, combination or variation of certain elements. Furthermore, it may be understood that also examples or elements that are not literally disclosed may be derived from the description and drawings by a person skilled in the art. Whereas different examples are described herein, it is understood that features of these examples may be used individually or in combination thereof to derive further variations beyond those explicitly describes herein.
In the example of
The carriage may carry one or a number of printheads. The printhead or printheads may deposit a printing fluid on the print medium 20, when the print medium is transported through a print zone in the medium advance direction Y. For example, one replaceable ink jet printhead or four, MCYK, ink inkjet printheads may be provided in the carriage. A printing fluid may be dispensed from the printheads which may be any fluid that can be dispensed by an inkjet-type printer or other inkjet-type dispenser and may include inks, varnishes, and/or post or pre-treatment agents, for example.
In the example of
The cutter assembly 14 may include a cutting blade 16 which may be a knife like blade or a rotary cutting blade, for example. The cutter assembly 14 further may include carriage to scan across the print medium 20, parallel to the scanning direction X of the printhead carriage. The cutter assembly 14 further may be movable vertically, i.e. in the Z direction, to engage and disengage the cutting blade 16 with the print medium 20.
The printer further may include a controller 32 controlling the printhead assembly 12, the cutter assembly 14, and transport of the print medium 20 in the print medium advance direction Y. The controller 30 can be a microcontroller, ASIC, or other control device, including control devices operating based on software or firmware, including machine readable instructions, hardware, or a combination thereof. It can include an integrated memory 32 and/or communicate with an external memory via a communication interface 34. It also may comprise a user interface, such as a graphic user interface. The same controller or separate controllers may be provided for controlling carriage movement, printhead actuation, print medium advance and the cutter assembly, for example. Different parts of the controller may be located internally or externally to the printer 10, in a concentrated or distributed environment.
The memory 32 may store a computer program 36. The computer program 36 may include a code to instruct the controller 80 to control the printer 10, including the printhead assembly 12 and the cutter assembly 14, to perform a printing and cutting process, as illustrated further below.
In one example, the print medium 20 may be advanced through a print zone of the printer 20 below the printhead assembly 12 step by step, in image slice length increments, while printing an image slice per step; and the print medium 20 may be cut at an X cut line position, at the cutting blade 16, after a number of print medium advances. When cutting, the cutter assembly 14 and the printhead assembly 12 may operate in parallel to simultaneously cut the print medium in the X direction between two images and print an image slice of a downstream image to be printed. Cutting hence can be performed without interrupting the printing process and the cutting process can be synchronized with the printing process, as explained in further detail below. This allows increasing the printing throughput because the print medium can be cut between an upstream image and a downstream image while the downstream image is being printed.
The printing process for generating the downstream image is controlled in such a way that, when printing image slice by image slice, after N medium advances, with N being a natural number, a target X cut line position of the print medium is aligned to the cutting blade 16 at the actual X cut line position. To align the target X cut line position and the actual X cut line position, the slice length of one or some of the image slices may be adjusted. In the context of this disclosure, the target X cut line position refers to the position of the print medium where the print medium is to be cut, and the actual X cut line position refers to the actual position of the cutter assembly in the printer.
In the example of
In an alternative configuration, not shown in the drawings, the printer includes a page wide print bar which extends across the width of the print medium 20, perpendicular to the medium advance direction Y. Also in this case, the print bar can print swathes on the print medium 20 after each medium advance movement. The cutter assembly 14 is carried by an associated cutter carriage and scans and cuts along a cut line C, downstream of the print zone.
The controller 30 instructs the printhead assembly 12 to print respective image slices between two medium advance movements for printing on subsequent portions of the print medium 20, instructs the cutter assembly 14 to cut between two defined medium advance movements, for separating a printed image from the print medium during the scanning action and without interrupting the print process of the print medium 20 currently undergoing printing. Examples of a printing and cutting process are illustrated in further detail with reference to
If printing is performed in an overlapping mode, such that one printed swath overlaps with the subsequent printed swath, an image slice length and corresponding medium advance may be smaller than the swath height. For ease of illustration, the following disclosure refers to a scenario where swath height SH, medium advance steps and image slice length are the same or approximately the same but the same principle as disclosed herein, mutatis mutandis, also can be applied to an overlapping print mode in which swath height, image slice length and medium advance steps are different from each other, taking into account a swath overlap.
A nominal distance ND between the printhead 104 and an X cut line position C where the cutting device is located in the printer can be a value specified by a printer manufacturer and may be stored in memory. The method obtains the nominal distance ND at block 110 in
The nominal distance ND may or may not be the distance across which the downstream printed image 102 is to move to align the target X cut line position with the actual X cut line position C. For example, an image margin may be defined by a print job, instructing the cutter assembly to generate a cut line at a defined distance to the leading edge of the image. In this example of the ideal case shown in
The method further obtains a predetermined slice length corresponding to a first medium advance step as determined by a print mode, for example; see block 112. The predetermined slice length may be a nominal slice length as determined by the print mode. The information obtained may be information stored in memory, internally or externally to the printer and provided to the controller directly or through a suitable interface and, at least in part, also may be information provided by a user, through sensors, such as position sensors, or otherwise input to the controller.
In general, the method determines and adjusts image slice lengths of the downstream image 102, at 114, in such a way that the leading edge of the downstream image 102 plus the margin M, i.e. the target X cut line position, arrives at the actual X cut line position C after a defined number of medium advances, such as N medium advances. The adjusted slice lengths of the image to be printed may be determined as a function of the nominal distance and an offset. In this example of the ideal case shown in
Accordingly, at 116, a leading edge of a to be printed image is aligned with the nozzle array 106 of the print head 104 and the first image slice is printed as shown in
After N−1 medium advances, the print medium is advance a further time by the swath height, to arrive at an Nth medium advance, with N=3 in this example, at 122. Then the target X cut line position of the print is aligned to the actual X cut line position C and a further image slice is printed while, at the same time, cutting the print medium at the X cut line position, at 124, as shown in
Accordingly, when the print medium is advanced through the print zone below the printhead 104 of the printer, slice by slice, in slice length increments, an image slice is printed between each medium advance. After N medium advances, with N being a natural number and N=3 in this example, the target X cut line position of the print medium is aligned to the X cut line position C and the print medium is cut at the X cut line position C while, at the same time, printing the next (in this example, the fourth) image slice, at 124.
In many instances, a real world scenario deviates from this ideal case. A number of causes for such deviation may occur individually or in any combination thereof. For example, the printhead may be offset from its nominal position by a printhead calibration error. In another example, the cutting device and hence the X cut line position may be offset from its normal position by a cutting device calibration error. Further, the margin M may not be such that an integer number of equal length medium advances will align the target X cut line position of the print medium with the actual X cut line position of the cutting device. Another deviation may be caused by a given print mode which selects a leading nozzle row of the nozzle array 106 for printing the first swath which is offset from the most downstream nozzle row; that is, according to a given print mode, a first swath is to be printed by an upstream portion of the nozzle array 106, instead of the entire nozzle array. These and other deviations, either individually or any combination thereof, may be taken into account by adjusting a slice length of an image to be printed as a function of the nominal distance and an offset. The print medium then is advanced according to the adjusted slice length.
The adjustment may be made relative to a nominal slice length as determined by the print mode. The slice length e.g. may be reduced relative to the nominal slice length to reduce the length of a predetermined image slice. Under some circumstances, the adjustment also could increase the length of a predetermined image slice. In one example, the image slice to be adjusted is a first image slice, a second image slice or an Nth image slice of the downstream image to be printed and wherein the length of other image slices corresponds to the nominal slice length.
The example of
In the example of
Additionally, an image margin may be defined by the print job, instructing the cutter assembly to generate a cut line at a defined distance to the leading edge of the downstream image. Also in this example, the margin M is specified as 3 mm, without any limitation thereto.
There may be further variations creating or contributing to an offset, such as a different image margin and/or a print mode which does not start printing with the most downstream nozzle row of the nozzle array 106.
A first image slice length, also referred to as predetermined slice length, as defined by a print mode is obtained at 212 in
If, in the example of
Instead of proceeding as shown in
The predetermined image slice may be adjusted in such a way that an integer number of medium advances, corresponding to an image slices of the nominal swath height or to the predetermined slice length determined by the print mode, plus one medium advance corresponding to the adjusted image slice length will align the target cut line with the X cut line position C. With reference to the example shown in
x may be the number of medium advances corresponding to the predetermined slice length which the downstream printed image could advance without the target cut line moving beyond the X cut line position C. Accordingly, the print medium may be advance x times the nominal slice length and once the adjusted slice length so that a total of N medium advances aligns the target X cut line position with the actual X cut line position C, with N=3 in this example.
In the example of
It is determined whether the print medium has been advanced by a predetermined number of steps, such as N=3 in this example. If no, printing at 220 and advancing at 222 is repeated. After N medium advances, it is recognized that the target X cut line position of the print medium is aligned to the X cut line position C, as shown in
As explained above, in addition to a calibration error of the cutting assembly or the printhead assembly, there may be further causes which introduce an offset to the nominal distance ND. For example, the margin M may not be such that integer number of equal length medium advances will align the target X cut line position of the print medium with the actual X cut line position of the cutting device. Another deviation may be caused by a given print mode which selects a leading nozzle row of the nozzle array 106 for printing the first swath which is offset from the most downstream nozzle row; that is, according to a given print mode, a first swath is to be printed by an upstream portion of the nozzle array 106, instead of the entire nozzle array. These and other deviations, either individually or any combination thereof, may be taken into account by adjusting a slice length of an image to be printed as a function of the nominal distance and an offset. The print medium then is advanced according to the adjusted slice length.
A further example of adjusting the length of an image slice is explained with reference to
Further, the position of the leading edge of the first swath relative to the nozzle array 106 is obtained and, more specifically, the position of the most downstream row of nozzles to be used for printing the first swath as defined by the print mode, at 312. This is done because some print modes do not use the entire nozzle array for printing a first swath but may use an upstream portion, middle portion or downstream portion of the nozzle array.
The method proceeds with calculating an offset based on a defined margin, the position of the cutter assembly relative to the printhead, including any calibration error if there is one, the position of the most downstream nozzle row used for printing the first swath previously obtained and the length of the first two medium advances as previously obtained, at 314. If, based on the margin and the calibration error, for example, an offset to be applied to the first image slice is determined, the method proceeds with shifting the first nozzle row that will print the leading edge of the first image slice in a first pass of the print out to adjust the first slice length, similar to what is shown in
Accordingly, the first image slice actually printed will include a fraction of the first image slice as originally determined by the print mode. Accordingly, in the first and subsequent passes of printing image slices, the image will be shifted by the same offset, propagating the offset through the subsequent image slices down to the last one. That is, the size of a first image slice to be printed is recalculated to allow the first size of the image to be reduced in length and the length of the further slices to remain as determined by the print mode. This implies that the image content slicing will be shifted throughout the image with those pixels not depicted in the first slice shifted to the second slice and so forth. This will be propagated until the end of the image. If a masking scheme is applied to the nozzle array, the mask as such may remain unchanged but the respective nozzle rows used for printing each slice may be shifted.
It even may happen that the slice length of the first image slice is adjusted to zero and the length of the second image slice is adjusted so that a sum of the adjusted second slice length plus an integer multiple of the nominal slice length corresponds to the distance between the leading edge of an image to be printed and the X cut line position.
Accordingly the method proceeds with printing subsequent image slices, 318, and advancing the print medium accordingly, at 320, as determined for the first and subsequent passes of printing image slices. The length of print medium advance corresponds to the length of the image slice just printed. For example, the first image slice and the first print medium advance may have an adjusted length and the second and further image slices and print medium advances may have a nominal length. After the print medium has been advanced N times, the system will know that the target X cutline position is aligned to the actual X cutline position C and will proceed with simultaneous the printing the next image slice and cutting the print medium, at 322.
In the examples, after an Nth medium advance, the next image slice can be printed simultaneously with cutting the print medium, at 322, so that no extra stop will be made for cutting the print medium. Instead of adjusting the length of the first image slice is also is possible to adjust the length of an image slice further upstream up to the Nth image slice. The described method provides a flexible strategy to parallelize printing movement and cut operations whenever variable printing parameters change. For different print modes and different user selections, e.g. with regard to image margins, image slicing can be adapted. A user can freely select and change image margins, even between subsequent printed images and beyond a selection offered by a printer. Additionally, different hardware tolerances of the printer, including the printhead assembly and the cutting assembly, can be compensated. Printing throughput can be enhanced.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/032709 | 5/16/2019 | WO | 00 |