BACKGROUND

[0001] Many printers deposit print material on a print medium. Printing may be carried out by passing the print medium along a printing path. A printer carriage may be passed over the print medium at a print location along a scan axis. The scan axis may be perpendicular to the direction of movement of the print medium along the printing path. Print media may be made of materials such as paper, Mylar, vinyl and textiles, for example. Print media may have different thicknesses.

[0002] Printers may for example be inkjet printers. Inkjet printers may be provided with printheads for firing or spitting drops of print material, such as ink or other printing fluid.

BRIEF DESCRIPTION OF DRAWINGS

[0003] Non-limiting examples will now be described with reference to the accompanying drawings, in which:

[0004] Figure 1 is a simplified schematic of a device according to some examples; [0005] Figure 2 is another simplified schematic of a device according to some examples;

[0006] Figure 3 is a flowchart of a method according to some examples; and [0007] Figure 4 is another flowchart of a method according to some examples.

DETAILED DESCRIPTION

[0008] In some examples, there are provided methods and devices for predicting print material usage for a print instruction (print job) or a series of print instructions. Print material usage prediction/estimation is a process of forecasting the quantity of print material that will be consumed during the printing operation of a certain job or image relating to a print instruction.

[0009] In accordance with some examples described herein, and shown in Figure 1 , there is provided a device 10. The device 10 may comprise a print material usage database 100. The print material usage database 100 may store data relating to print material usage for previously executed print instructions. The device 10 may further comprise a print material usage estimator 110. The print material usage estimator 110 may estimate use of print material to carry out a print instruction, based on the stored data. The device 10 may further comprise a controller 120 to control a service strategy, for the printer which is to execute the print instruction, based on the estimated use.

[0010] The device 10 may in some examples be a printer or a print controller.

[0011] When executing a print instruction, a printer may carry out processes including calibration, servicing and printing. More specifically, print material usage, when carrying out the print instructions, may be affected by the print instruction itself, for example the number of drops indicated in a raster file; the selected print mode or print strategy, which may include factors such as print resolution, percentage of ink, print masks used, number of passes of the printhead and media type used; servicing triggered by the user, for example the level of print head primes; automatic servicing while printing, which may take into account the time from last drop detection to determine spitting actions, for example; and calibration plots launched, such as alignment plots, colour calibration, ICC profiling, etc.

[0012] Further factors affecting the print material usage may include, for example, the print mode selected such as fast, production or quality, and the print medium onto which the print instruction is to be printed. Print media may have a variety of different properties which affect the visual appearance of an image print on the medium, such as roughness, colour and visual appearance of the medium. Depending on the print medium used, more or less print material may need to be used in order to achieve a specific print quality or appearance of the printed image. For example, textiles (fabrics) may tend to use more print material (then paper, for example), because print material may enter or be absorbed into the fibres of the medium. Transparent or translucent print media may, in use, be illuminated with a back or front light, and therefore may benefit from greater print material density to achieve brighter colours. In some examples, some colours may fade other colours. Therefore, additional print material may be use to compensate for this fading. Also, the status of the printer or the printheads may affect the print material needed to carry out a print instruction, for example, if the printer has recently had the printhead(s) replaced.

[0013] In some examples, the print material usage database 100 may be a general or specific purpose storage device, such as a memory. The print material usage database 100 may store data relating to print material usage for previously executed print instructions. The previously executed print instructions may include actual print instructions, example print instructions and usage indications to teach the print material usage estimator 110, before actual print instructions are carried out. The print material usage database 100, in addition to print material usage data, may store metadata useful for determining print material usage, such as the age of the printer or printhead nozzles and the age of the print material since first use.

[0014] In some examples, the print material usage estimator 110 may use the stored data to estimate an amount of print material consumed to carry out the print instruction. The estimate may take into account print material consumed for printing, servicing calibration, etc.

[0015] In some examples, the controller 120 may be a service strategy controller and may control a service strategy for the printer carrying out the print instruction. The controller 120 may control the service strategy based on the estimated use. The controller 120 may further detect how much print material is available, when carrying out control of the service strategy. For example, if the estimated use indicates an amount of print material slightly greater than the amount available, adapting the print strategy may allow the print instruction to be carried out using the available print material, without running out.

[0016] In some examples, the print material usage database 100 and the print material usage estimator 110 may, in combination, be a machine learning engine or machine learning classifier.

[0017] Machine learning is a form of artificial intelligence that may be employed to allow computers to evolve behaviours based on empirical data. Machine learning may use training examples to capture characteristics of interest. Training data may be seen as examples that illustrate relations between observed variables. A focus of machine learning research may be to automatically learn to recognize complex patterns and make intelligent decisions based on data.

[0018] Machine learning may be used for application such as print material/ink usage prediction, as described above.

[0019] In some examples, the print material usage estimator 110 may access data, stored on the print material usage database 100, relating to, for example, printing parameters and the condition of the printer or printheads identifying the image, and generate a prediction of a likely amount of the print material consumption for the given print instruction. [0020] The described examples may allow for up-front (before the print instruction is executed) estimation of print material usage for a given job (image or series of images). This information is useful for the printer owner to both, calculate up-front the cost of printing a given image, and to know if there will be enough ink supply as to print the given image.

[0021] In some examples, in response to the estimated use of print material exceeding an amount of print material available, the controller 120 changes the service strategy to a service strategy with a lower print material usage.

[0022] A service strategy having a lower print material usage may include programming fewer printhead nozzle spitting functions during execution of the print instruction. Further examples may include printhead nozzle servicing by suction under the nozzle or applying pressurised air onto the container containing the print material, inside the nozzle. Varying the pressure may affect ink usage.

[0023] In some examples, in response to the estimated use of print material exceeding an amount of print material available, the controller 120 changes the service strategy to a non-ink servicing strategy.

[0024] Non-ink servicing strategies may include functions such as wiping a printhead nozzle. Non-ink servicing strategies may also be referred to as print material-less servicing strategies. Such servicing strategies may use no print material in carrying out the servicing.

[0025] In accordance with some examples described herein, and shown in Figure 2, there is provided a device 10, as described above, wherein the device 10 is a large format printer and may be a latex large format printer, using latex-based print material. The device 10 may further comprise a print material usage meter 130 to measure use of print material. The print material usage estimator 110 may update, during or after printing, the future estimated use based on the measured use.

[0026] A large format printer may for example be specialized printing equipment which may accommodate large printing jobs (for example standard A2 size or larger), such as posters, large maps or charts, store displays, trade show wall panels, blueprints, banners, large-scale advertisements such as building wraps, etc. In particular, HP large format printers may print on rolls that are minimum 24” wide and 25 m long. HP latex large format printers may print on rolls of minimum 60” wide and minimum 50 m long. In accordance with some examples described herein, and shown in Figure 3, there is provided a method. The method may comprise assessing S301 how much print material is consumed when executing a print job, based on a database of previous print jobs. The method may further comprise checking S302 how much print material is available in a printer for executing the print job. The method may further comprise controlling S303 supply of the print material based on a determination of whether the available print material is sufficient for execution of the print job.

[0027] A database of previous print jobs may be stored in any suitable data storage device, such as a memory. The database may include data relating to various aspects of previous print jobs, including any factors which may affect print material usage, as detailed above.

[0028] The assessing S301 may be carried out by a machine learning engine as described above. The assessing S301 may involve a comparison between the print job to be printed and past print jobs.

[0029] Checking S302 print material availability may be performed by any suitable means. For example, the checking S302 may include detecting, by a detector, an amount of print material in a print material container, such as an ink cartridge, or determining a print material allowance, for example if a user has a contract for or has pre-purchased a specific amount of print material. A print material allowance, and remaining amount of that allowance, may be checked through the same detector or by any suitable meter.

[0030] Controlling S303 the print material supply may include restricting or increasing the supply rate and adapting the print and/or service strategy accordingly.

[0031] In some examples, controlling supply comprises changing a print resolution for the print job.

[0032] Changing a print resolution may be achieved by instructing a change in the addressable positions at which print material is printed onto the print medium (i.e. positions to which ink is fired).

[0033] In some examples, the method may further comprise, after the print job is completed, updating the database and the assessment, based on a measured amount of print material used.

[0034] By adding data relating to each print job, future assessments may be made more accurate. Further, measured print material usage may be compared with the assessed amount of print material which would be consumed to highlight any inaccuracies and again make future assessments more accurate.

[0035] In some examples, controlling supply comprises changing the number of print passes performed when carrying out the print job. [0036] Increasing or decreasing the number of print passes may have a significant effect of the print material usage and therefore may be an effective way to control how much print material is used when carrying out the print instruction. For example, when a higher number of print passes is used more ink may be used in total, but less ink may be used per pass, in order to reach a higher overall image quality. Using less ink per pass may mean ink drops on the media may be separated and interaction between drops may be reduced.

[0037] In some examples, controlling supply comprises, changing print material concentration.

[0038] In accordance with some examples described herein, and shown in Figure 4, there is provided a method. The method may comprise estimating S401 an amount of print material consumed to carry out a print job, based on a database of previous print jobs, each previous print job having quantifiable print variables. The method may further comprise controlling S402 a print strategy for carrying out the print job, based on the estimate.

[0039] Estimating S401 the amount of print material consumed to carry out the print job may take into account at least one quantifiable print variable. Previous print jobs, including data relating to quantifiable variables thereof may be stored such that each estimate may draw on individual variables or multiple variables taken in combination. Print variables may include number of passes, print job resolution, servicing events during printing, etc.

[0040] In some examples, controlling the print strategy comprises changing an amount of print material to be used for the print job.

[0041] In response to an estimate that the amount of print material consumed to carry out a print job may for example exceed a specific threshold or may exceed an amount of available print material, the amount of print material to be used for a print job may be changed, for example by any of the means described above.

[0042] In some examples, controlling the print strategy comprises changing a calibration plot.

[0043] A calibration plot may consume significant print material resources to ensure accuracy of the printing before carrying out the print job. Such a calibration plot may be simplified, reduced in size, programmed to use alternative print material (such as a colour not used for the print job), or be controlled to reduce the amount of print material used for the same sized plot. Depending on the nature of the print job, a calibration plot may be changed without affecting the accuracy of the printing of the print job. [0044] In some examples, controlling the print strategy comprises comparing the estimated amount of consumed print material with a detected amount of print material available. Further, in response to a determination that the available print material is not sufficient to carry out the print job, the method may comprise lowering a print quality of the print job. Lowering the print quality of the print job may be done for example by reducing the print material density on the print medium.

[0045] In some examples, in response to a determination that the available print material is not sufficient to carry out the print job, the method may further comprise changing a print order for images in the print job, to increase a number of images printable with an amount of available print material.

[0046] If a print job includes more than one image for printing, each image may have an associated print material consumption. Therefore, if a sequence of images in a print job are given, these may be ordered so that the maximum number of images may be printed with the available print material resources. In some examples, the images may be ordered to prioritise certain images over others.

[0047] In some examples, controlling the print strategy comprises changing a number of print passes when printing.

[0048] In accordance with some examples, users of the printers may have the possibility to provide an accurate print material consumption estimate or assessment, which may allow more accurate cost calculations associated with a print job. Further, being able to estimate, in advance, the print material consumption may allow print material stock to be acquired/ordered/provided to ensure that there will be enough print material for a production plan.

[0049] In some examples, the methods described above may be carried out on an apparatus comprising a processor and memory. In some further examples, there is provided a non-transitory computer-readable storage medium storing instructions which, when executed on a processor, cause the processor to carry out the method as described above.

[0050] While the method, apparatus and related aspects have been described with reference to certain examples, various modifications, changes, omissions, and substitutions may be made without departing from the scope of the present disclosure. It is intended, therefore, that the methods, devices and related aspects be limited only by the scope of the following claims and their equivalents. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that those skilled in the art will be able to design many alternative implementations without departing from the scope of the appended claims.

[0051] The word “comprising" does not exclude the presence of elements other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single unit may fulfil the functions of several units recited in the claims.

[0052] The features of any dependent claim may be combined with the features of any of the independent claims or other dependent claims.