WO2023022700A1

WO2023022700A1 - Printing media deformation constants

Info

Publication number: WO2023022700A1
Application number: PCT/US2021/046094
Authority: WO
Inventors: David MUNOZ NAVARRO; Ricard EJARQUE MONTALVO; Victor LORENTE TEJERO; Albert ESTELLA AGUERRI
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2023-02-23

Abstract

Examples include a method comprising receiving, at a printer controller, nominal printing data associated to a graphical representation. The method also comprises measuring, with a sensor connected to the printer controller, a printing media width in a print zone of the printer and associating, at the printer controller, the measured printing media width with a printing media length deformation using a deformation constant. The method further comprises modifying the nominal printing data to obtain corrected printing data taking the measured printing media width and the printing media length deformation into account.

Description

PRINTING MEDIA DEFORMATION CONSTANTS

BACKGROUND

[0001] This disclosure generally relates to the printing of graphical representations on printing media. Due to the generally two dimensional nature of printing media, such printing media are widely used as a support to share information in the written or graphical form. Such printing media may be submitted to mechanical tension during transportation within media processing devices such as printers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 illustrates an example method and a printer to execute the method.

[0003] FIG. 2 illustrates another example method and a printer to execute the method.

[0004] FIG. 3 illustrates another example method and a printer to execute the method. -

[0005] FIG. 4 illustrates another example method and a printer to execute the method.

[0006] FIG. 5 illustrates another example method.

[0007] FIG. 6 illustrates another example method.

[0008] FIG. 7 illustrates another example method.

[0009] FIG. 8 illustrates an example printer and storage medium.

[0010] FIG. 9 illustrates another example printer and storage medium.

DETAILED DESCRIPTION

[0011] While printing media may be made of a wide variety of materials, some of such materials may take a first shape when loose, and take a different, deformed shape when submitted to mechanical tension or mechanical forces, in particular when transported towards a print zone, or when held into a print zone of a printer. Tensing printing media in the print zone can in some cases contribute to reducing or even supressing wrinkles or bubbles which could lead to printing media jams, for example in cases of using a scanning printhead carriage in the print zone. If a graphical representation gets printed on a deformed, tensed, printed media, such graphical representation may in turn appear deformed once the printed media returns to an original shape as it ceases to be submitted to an external tension or force. Such deformation during printing may introduce a default such as grain. Avoiding or reducing the occurrence of such a graphical representation deformation forms the foundation of the present disclosure. As will be described in more details below, effective printing media deformation is taken into account to modify printing data such that a printed graphical representation appears correct once printed. Taking into account such deformation takes place by measuring a printing media width, and by deducing, from the printing media width and from a deformation constant, a printing media length deformation. Deformation along a length was indeed found to be related to deformation along the width for a given media in a given print zone, such relation being through a deformation constant. Both length and width deformation of a printing media may thereby be deduced through measurement of the media width. In some examples, the printing media is, when submitted to mechanical handling, being stretched both in width and length. Obtaining deformation information from a width measurement according to this disclosure avoids using dedicated marks or a dedicated pattern for this same purpose, whereby such dedicated marks or pattern may occupy available printable space. In some cases, no printing space would be available for such dedicated marks or pattern. Obtaining deformation information from a width measurement according to this disclosure permits taking into account the situation at the time of the measurement, in particular taking into account factors which may influence deformation such as an amount of printing fluid ejected onto the printing media, an amount of mechanical tension applied to the printing media, ambient conditions such as ambient humidity or temperature, or a combination of these. While such factors may influence the amount of deformation, it was found that such deformation may be characterized as described in this disclosure based on width measurement and on a deformation constant relating width and length deformation. Obtaining deformation information from a width measurement according to this disclosure permits taking into account different situations which may occur at different places of a same printing media roll or sheet, for example between a beginning and an end of a roll or sheet of printing media. Obtaining deformation information from a width measurement according to this disclosure also permits taking into account different situations which may occur with different printing media from a same batch of printing media.

[0012] Figure 1 schematically illustrates an example method 100 comprising, in block 101, receiving, at a printer controller 120, nominal printing data 130 associated to a graphical representation 140.

[0013] The receiving 101 should be understood as comprising the reception or loading of digital data, in particular nominal printing data, wirelessly or by wire, locally or remotely, from a network or from a local data input device. The digital data may in some examples be in a format such as a Tagged Image File Format (TIF or TIFF), Joint Photographic Experts Group (JPEG), Graphics Interchange Format (GIF), Portable Document Format (PDF), Printer Command Language (PCL), PostScript or Portable Network Graphics (PNG), among others. The printing data is considered nominal in that it is original printing data which is not, when received, taking into account changes which will take place as described in this disclosure and taking media deformation into account. The nominal printing data 130 is associated to a graphical representation 140 which may for example be a text, an image or a graph. A graphical representation should be understood as a tangible result of printing of the printing data onto a printing media using, for example, printing fluid.

[0014] The data is received at a printer controller 120. A controller according to this disclosure should be understood as a hardware device managing digital data in order to control a printing process. As will be explained for example in the context of Figures 8 and 9, the controller 120 can comprise a processor, a storage coupled to the processor, and an instruction set. In an example, the controller is an electronic controller comprised in a printer 110, the printer controller including a processor and a memory or storage component and other electronic circuits for communication including receiving and sending electronic input and output signals. In some examples, the printer controller is connected to and remote from a printer controlled by the controller. An example electronic controller receives data from a host system, such as a computer, and may include memory for temporarily storing data. Data may be sent to the controller along an electronic, infrared, optical or other information transfer path. Data represents, for example, a document or a file to be printed.

[0015] Method 100 comprises, in block 103, measuring, with a sensor 150 connected to the printer controller 120, a printing media 160 width Wm in a print zone of the printer 110. The measuring should be understood as a sensing or estimating, with the sensor 150, of the effective width of a specific tangible printing media on which the graphical representation may be printed. The sensor may proceed with the sensing mechanically, for example by contact or by force sensing with the printing media, or may proceed with the sensing of electromagnetic radiation, for example through ultrasound, infrared or visible light. The sensor may be an optical sensor. The sensor 150 may be connected to the printer controller 120 wirelessly or by wire in order to exchange digital or analog data with the printer controller, such data being related to the measured printing media width. In some examples, the sensor may span the entire width of the printing media, as represented for examples in Figure 1. In some other examples, the sensor may span a portion of the entire width of the printing media and may be a static, or a mobile sensor.

[0016] The printing media width should be understood as a dimension of the printing media along a direction at a non zero angle with a printer media advance direction in the print zone. In some examples, the width is along a direction substantially perpendicular to a printer media advance direction, substantially perpendicular being understood for example as between 85 and 95 degrees.

[0017] The printing media should be understood as a generally two dimensional media having a width, a length and a thickness, the thickness being very significantly smaller than both of the width and the length, the thickness being for example of less than 100 times either of the length or width. The printing media may be provided as a cut sheet or as a roll. The printing media may comprise cellulose fiber, polymeric fibers, natural fibers, or a combination of these. The printing media may be a laminate. The printing media may be a paper based printing media or a textile printing media, being a woven or non-woven textile printing media. A textile printing media may be a woven printing media, the woven printing media comprising yams substantially aligned with the printing media width and yarns substantially aligned with a media advance direction, substantially aligned being understood as aligned within -5 to +5 degrees for example. In some examples, the printing media is provided in the form of a roll and has a nominal printing media width, at rest, of at least 900mm, of at least 1000mm or of at least 1200mm, such large format printing media being particularly prone to deformation due to its relatively large size.

[0018] The printing media width is measured in a print zone of the printer. A print zone should be broadly understood as comprising a printing area in which the printing takes place, an uptake area leading to the printing area, and a downstream area following the printing area, the uptake area, printing area and downstream area following each other in this order along a media advance direction of the printer. Printing may take place for example by applying a printing fluid onto the printing media. In some examples, printing fluid is applied to the printing media in the printing area when printing. In some examples, the print zone comprises a printing area facing a scanning printhead carriage. In some examples, the print zone comprises a printing area facing a page wide array printhead. In some examples, the print zone is comprised between an input roller and an output roller in a roll-to-roll configuration, the print zone comprising an uptake area from the input roller to a printing area, and a downstream area from the printing area to the output roller. In such a roll-to-roll configuration, the sensor is in some examples located in the printing area in order to measure the width precisely in this area. In other examples, the sensor is located in one of the uptake area or downstream area of the print zone, away from the printing area, in order to measure the width close to the printing area while reducing or suppressing risks of soiling the sensor with printing fluid spray, the sensor being for example separated from the printing area by at least 1cm, at least 2cm, at least 3cm or at least 5 cm. In some specific examples, the sensor is located in the uptake area in order to measure the width prior to printing taking place and in order to permit proactively taking such width into account prior to printing. In some examples, the print zone comprises a platen. In some examples, the print zone comprises a flat platen. In some examples, the print zone comprises a roller shaped platen. The printer may operate according to different printing technologies. In some examples, the printer is a thermal inkjet printer. In some examples, the printer is a piezo inkjet printer. In some examples, the printer is configured to eject an aqueous printing fluid. In some examples, the printer is configured to eject a printing fluid comprising an organic solvent. In some examples, the printer is configured to eject a printing fluid comprising a latex based solvent. In some examples, the printer is configured to eject a UV (ultraviolet) curable printing fluid.

[0019] Method 100 comprises, in block 105, associating, at the printer controller, the measured printing media width Wm with a printing media length deformation AL using a deformation constant K. The associating should be understood as encountering or calculating a specific printing media length deformation as a function f of the measured printing media width Wm and of the deformation constant K. In some examples, the associating comprises using a table. In some examples, the associating comprises using a mathematical formula. In some examples, the associating comprises taking a nominal printing media width into account, such nominal printing media width corresponding to a width of the printing media at rest. The nominal printing media width may be measured or may be provided for example by a printing media manufacturer. In some examples, the associating comprises taking a printing media width deformation into account, the printing media width deformation corresponding for example to a difference between the measured printing media width and a nominal printing media width. In some examples, the deformation constant is a unit-less constant corresponding to a ratio between a printing media width deformation and a printing media length deformation. In some examples, the deformation constant takes a same value across a batch of printing media. In some examples, the deformation constant varies across a batch of printing media and is checked, measured or calculated periodically. In some examples, the deformation constant is measured using the printer controller. In some examples, the deformation constant is provided, for example by a printing media manufacturer. In some examples, the media length deformation is in relation to a nominal media length which may for example be measured or otherwise provided. Using a deformation constant according to this disclosure permits ascertaining a printing media deformation in length from a measured printing media width. This permits evaluating the overall deformation of the printing media in some examples from a single unidirectional measurement being the printing media width measurement according to this disclosure.

[0020] In some examples, the deformation of the printing media in the print zone in a given dimension, being length or width, is of more than 1%, more than 2%, more than 3%, more than 5%, more than 10% or more than 15% when tensed compared to the same nominal dimension at rest. Such deformation may result in a reduction or in an increase compared to the nominal dimension considered.

[0021] Method 100 comprises, in block 107, modifying the nominal printing data to obtain corrected printing data taking the measured printing media width and the printing media length deformation into account. The modifying may take place at the printer controller, or may take place at a data processing system external to the printer controller. In some examples, the modifying takes place at the printer controller in order to avoid or reduce data transmission to a data processing system external to the printer controller. In some examples, the modifying takes place at a data processing system external to the printer controller in order to rely on external computing resources and avoid or reduce consuming data processing resources at the printer controller. The modifying may take place at one stage of different stages of a printing data pipeline. The printing data may indeed correspond to digital data at one of different stages of a printing pipeline, upstream or downstream from such printing pipeline. The printing data may be one of digital data corresponding to the graphical representation to be printed, digital data following a rasterising process, digital data following a halftoning process, or digital data directly controlling electronic signals of, for example, ejecting chambers of nozzles of printhead dies.

[0022] In some examples, the measured width is smaller than a nominal width and the media length deformation is a positive media length deformation whereby the effective media length in the print zone is longer than a nominal media length. In such an example case, the modifying leads to corrected printing data covering a respective reduced width and respective increased length. [0023] In some examples, the measured width is larger than a nominal width and the media length deformation is a positive media length deformation whereby the effective media length in the print zone is longer than a nominal media length. In such an example case, the modifying leads to corrected printing data covering a respective increased width and respective increased length, as represented for example in the case of the starlike motive 140 of Figure 1. In some examples, such a situation is encountered in cases of thermal dilatation and expansion in the print zone.

[0024] The relation between width and length deformation may be printing media specific and printer specific. In some examples, an increased width may lead to an increased length. In some examples, a reduced width may correspond to an increased length. Such difference in behavior may for example be due to the nature of the printing media concerned, and may for example be dependent on a specific weaving pattern of a specific woven textile printing media interconnecting a width yam deformation to a length yarn deformation.

[0025] Figure 2 represents an example method 200. Example method 200 comprises blocks 101, 103, 105 and 107 as described for example in the context of example method 100. Example method 200 is illustrated in combination with a printer controller, printing data, printing media, and measured printing media width as described in the context of method 100 and carrying the same reference numerals. The graphical representation 240 of method 200 is modified in a manner different from the graphical representation 140 of method 100 for illustrative purposes.

[0026] Example method 200 further comprises, in block 209, tensing the printing media 160 in the print zone of a printer 210 in a roll-to-roll configuration, whereby the measuring of the printing media width comprises measuring of the tensed printing media width. A roll-to-roll configuration should be understood in that the print media is tensed between different rollers such as, for example, rollers 261 and 262, the print zone being located between such rollers. In some examples, the width is along a direction substantially parallel to an axis of the rollers, the rollers having axis parallel to each other, substantially parallel being understood for example as within -5 and +5 degrees. Such roll-to-roll configurations results in a tensing of the media, which in turn results in a deformation of the media, for example along a length of the printing media.

[0027] In Figure 2, the sensor 250 connected to the printer controller to measure the printing media width in the print zone of the printer spans a portion of the width of the printing media. In some examples, the sensor may be configured to have a field of view spanning an entire width of the printing media and may be a static sensor.

[0028] Figure 3 represents an example method 300, the example method 300 comprising blocks 101, 103, 105 and 107 as discussed in the context of method 100. While not represented here, method 300 could further comprise a block such as block 209 of method 200. Method 300 is represented in a roll-to-roll context of printer 210 of method 200, even though other configurations could be considered. Method 300 further comprises, in block 311, displacing the sensor across the print zone of the printer along the printing media width. Displacing the sensor permits utilizing a compact sensor to proceed with the measurement. Displacing the sensor can permit detecting the width by detecting edges of the printing media, for example optically.

[0029] Figure 4 represents an example method 400, the example method 400 comprising blocks 101, 103, 105 and 107 as discussed in the context of method 100. While not represented here, method 400 could further comprise a block such as block 209 of method 200. While not represented here, method 400 could further comprise a block such as block 311 of method 300. Method 400 is represented in a roll-to-roll context of method 200, even though other configurations could be considered. In example method 400, the printer 410 comprises a scanning printhead carriage 411 for printing the graphical representation in a plurality of printhead swaths, whereby the measuring of the printing media width and the modifying of the nominal print data is iterated at different swaths of the plurality of printhead swaths. In some examples, the scanning printhead carriage scans across the printing media width as the printing media progressively advances along a media advance direction aligned with the printing media length. In some examples, the measuring of the printing media width and the modifying of the nominal print data is iterated at each swath of the plurality of printhead swaths, such a frequency of measuring enabling a real time modification of the nominal print data. In other examples, the measuring of the printing media width and the modifying of the nominal print data is iterated at some swaths of the plurality of printhead swaths, thereby reducing a frequency of modification of the nominal print data and saving computing resources. In some example, the measuring of the printing media width takes place at a specific swath and the corrected printing data taking the measured printing media width at the specific swath into account comprises data corresponding to a swath following the specific swath. Such a functioning from taking a specific swath measurement into account to correct data for a following swath can lead to a faster operation, the corrected data being implemented as the printhead prepares for printing such following swath. In some examples, the measuring of the printing media width takes place at a specific swath and the corrected printing data taking the measured printing media width at the specific swath into account comprises data corresponding to a swath directly following the specific swath. In some examples, the swaths are applied in a multi pass mode whereby the scanning printhead flies multiple times over a same area of the printing media, for example in order to increase printing quality, or in order to control an amount of printing fluid dispensed on the printing media at a given time. One should note that the printing media deformation may be correlated to a quantity of printing fluid applied to the printing media in the print zone, in which case a frequent width measurement and correction of data according to this disclosure may permit adapting the printing to the deformation real time.

[0030] In some examples, the sensor is comprised in the scanning printhead carriage. This permits leveraging for width measurement a sensor which may also have alternative uses, and can permit applying an example method according to this disclosure to a printer while reusing a sensor previously provided for a different purpose. Examples of other purposes are enabling registration in case of dual side printing or reading of diagnostic patterns.

[0031] Figure 5 represents an example method 500, the example method 400 comprising blocks 101, 103, 105 and 107 as discussed in the context of method 100. While not represented here, method 500 could further comprise a block such as block 209 of method 200. While not represented here, method 500 could further comprise a block such as block 311 of method 300. Example method 500 further comprises, in block 508, calculating, at the printer controller, the deformation constant. This permits obtaining the deformation constant for example if such deformation constant is not provided by a printing media provider. Even if a deformation constant is provided, calculating such deformation constant at the printer controller can permit adapting or updating such deformation constant to a specific printing media in the print zone at a specific moment. The calculation may take place at a processor of the printer controller.

[0032] Figure 6 represents an example method 600, the example method 600 comprising blocks 101, 103, 105 and 107 as discussed in the context of method 100 and block 508 as discussed in the context of method 500. While not represented here, method 600 could further comprise a block such as block 209 of method 200. While not represented here, method 600 could further comprise a block such as block 311 of method 300. In this example method 600, block 103 further comprises measuring the printing media width in the print zone both in a tensed printing media configuration in block 609 and in a resting printing media configuration in block 610. The tensed printing media configuration may for example be obtained by applying tension using rollers in a roll-to-roll printer. The resting printing media configuration may for example be obtained by releasing tension from rollers in a roll-to-roll printer. The printer may comprise printing media advance mechanisms in configurations other than roll-to-roll, such as vacuum systems for example, which could either apply tension or be released in order to proceed with both measurements. Such combination of printing media width measurements can lead to obtaining a printing media width deformation value, for example if a printing media width in a resting media configuration is not otherwise provided. [0033] Figure 7 represents an example method 700, the example method 700 comprising blocks 101, 103, 105 and 107 as discussed in the context of method 100 and block 508 as discussed in the context of method 500. While not represented here, method 700 could further comprise a block such as block 209 of method 200. While not represented here, method 700 could further comprise a block such as block 311 of method 300. Example method 700 further comprises block 709 of measuring a printing media length fed into the print zone both in a tensed printing media configuration and in a resting printing media configuration. Such combination of measurements can lead to obtaining a printing media length deformation value, for example if a printing media length in a resting media configuration is not otherwise provided. In some examples, printing media length is obtained from a roller encoder information. In some examples, printing media length is obtained from an angle of displacement and radius of a roller. In some examples, example method 700 further comprises blocks 609 and 610 as described in the context of Figure 6, thereby permitting calculating the deformation constant in block 508 as a ratio of, on one hand, length deformation from tensed to resting configurations to, on the other hand, width deformation from tensed to resting configurations.

[0034] Figure 8 schematically illustrates an example printer 810 which may be used for example as printer 110, 210 or 410 in any of the example methods 100, 200, 300, 400, 500, 600 or 700 hereby described. Printer 810 comprises a controller 120 such as the controller of any of printers 110, 210 or 410 for example, the controller comprising a processor 121, a storage 122 coupled to the processor, and an instruction set 123 to cooperate with the processor 121 and the storage 122 to: load original printing data associated to a graphical representation; sense a printing media width in a print zone of the printer; calculate a printing media length deformation based on the sensed printing media width and on a deformation constant; and correct the original printing data to obtain modified printing data based on the sensed printing media width and on the printing media length deformation.

[0035] The processor 121 may include a single-core processor, a multi-core processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), and/or any other hardware device suitable for retrieval and execution of instructions from the storage 122 or machine-readable medium to perform functions related to various examples. Additionally, or alternatively, the processor 121 may include electronic circuitry for performing the functionality described herein, including the functionality of instructions. The storage 122 may be any medium suitable for storing executable instructions, such as a random-access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk drives, optical disks, and the like. In some example implementations, the storage is a machine-readable medium which may be a tangible, non-transitory medium, where the term “non-transitory” does not encompass transitory propagating signals. The storage may be disposed within the processor-based controller, in which case the executable instructions may be deemed “installed” on the controller. Alternatively, the storage may be a portable (e.g., external) storage medium, for example, that allows controller to remotely execute the instructions or download the instructions from the storage medium. In this case, the executable instructions may be portion of an “installation package”. As described further herein below, the storage may be encoded with a set of executable instructions.

[0036] Figure 9 schematically illustrates an example printer 910 which may be used for example as printer 110, 210, 410 or as printer 810 in any of the example methods 100, 200, 300, 400, 500, 600 or 700 hereby described. Printer 910 comprises a controller 120 as described for example in the context of Figure 8. Printer 910 further comprises an input roller 961, feeding unprinted or virgin printing media towards the print zone, an output roller 962, picking up and storing the printed printing media from the print zone, and a scanning printhead carriage 911, whereby the scanning printhead carriage 911 is located between the input roller 961 and the output roller 962, for example in a roll-to-roll configuration, the scanning printhead carriage 911 comprising a sensor 950, for example such as sensor 150 or 250, to sense the printing media width. Such a printer 910 may be particularly prone to tensing, and thereby deforming, printing media in a print zone between the rollers, in particular a printing media such as a textile printing media stored in a roll form which may reach deformation levels in width or length of, for example, more than 5%. Such a printer 910 also permits using for width measurement a sensor loaded on the printhead carriage, the sensor reciprocating across the width of the printing media as printing take place.

[0037] Figures 8 and 9 also represent example non transitory machine-readable storage media such as storage 122 encoded with instructions executable by a processor such as processor 121, the machine-readable storage medium comprising: instructions to receive nominal printing data; instructions to measure a stretched printing media width in a print zone of the printer with a sensor of the printer; instructions to associate the measured stretched printing media width with a printing media length deformation using a deformation constant; instructions to modify the nominal printing data into corrected printing data as a function of both the measured printing media width and of the printing media length deformation; and instructions to print the corrected printing data on the stretched printing media, the obtained printed graphical representation corresponding to the intended representation due to the modification of the nominal printing data.

Claims

CLAIMS What is claimed is:

1. A method comprising: receiving, at a printer controller, nominal printing data associated to a graphical representation; measuring, with a sensor connected to the printer controller, a printing media width in a print zone of the printer; associating, at the printer controller, the measured printing media width with a printing media length deformation using a deformation constant; and modifying the nominal printing data to obtain corrected printing data taking the measured printing media width and the printing media length deformation into account.

2. The method according to claim 1, further comprising tensing the printing media in the print zone of the printer in a roll-to-roll configuration, whereby the measuring of the printing media width comprises measuring of the tensed printing media width.

3. The method according to claim 1, further comprising displacing the sensor across the print zone of the printer along the printing media width.

4. The method according to claim 1, whereby the printing media is a textile printing media.

5. The method according to claim 4, whereby the textile printing media is a woven printing media, the woven printing media comprising yams substantially aligned with the printing media width and yarns substantially aligned with a media advance direction.

6. The method according to claim 1, whereby the printer comprises a scanning printhead carriage for printing the graphical representation in a plurality of printhead swaths, whereby the measuring of the printing media width and the modifying of the nominal print data is iterated at different swaths of the plurality of printhead swaths.

7. The method according to claim 6, whereby the measuring of the printing media width and the modifying of the nominal print data is iterated at each swath of the plurality of printhead swaths.

8. The method according to claim 6, whereby the sensor is comprised in the scanning printhead carriage. The method according to claim 6, whereby the measuring of the printing media width takes place at a specific swath and whereby the corrected printing data taking the measured printing media width at the specific swath into account comprises data corresponding to a swath following the specific swath. The method according to claim 1, further comprising calculating, at the printer controller, the deformation constant. The method according to claim 10, further comprising measuring the printing media width in the print zone both in a tensed printing media configuration and in a resting printing media configuration. The method according to claim 10, further comprising measuring a printing media length fed into the print zone both in a tensed printing media configuration and in a resting printing media configuration. A printer comprising a controller, the controller comprising a processor, a storage coupled to the processor, and an instruction set to cooperate with the processor and the storage to: load original printing data associated to a graphical representation; sense a printing media width in a print zone of the printer; calculate a printing media length deformation based on the sensed printing media width and on a deformation constant; and correct the original printing data to obtain modified printing data based on the sensed printing media width and on the printing media length deformation. The printer according to claim 13, whereby the printer further comprises an input roller, an output roller and a scanning printhead carriage, whereby the scanning printhead carriage is located between the input roller and the output roller, the scanning printhead carriage comprising a sensor to sense the printing media width. A non transitory machine-readable storage medium encoded with instructions executable by a processor, the machine-readable storage medium comprising: instructions to receive nominal printing data; instructions to measure a stretched printing media width in a print zone of the printer with a sensor of the printer; 15 instructions to associate the measured stretched printing media width with a printing media length deformation using a deformation constant; instructions to modify the nominal printing data into corrected printing data as a function of both the measured printing media width and of the printing media length deformation; and instructions to print the corrected printing data on the stretched printing media.