Hewlett-packard Development Company, L.p.

Andreu Vinets Alonso

Antonio Gracia Verdugo

Josep Maria Bel Calavia

Andrei Alexandru Dafinoiu

Ignasi Bonjoch Roma

David Toussaint

Aleix Fort Filgueira

Javier Deocon Mir

Examples relate to a computer implemented method comprising, based on a vulnerable nozzle map indicating one or more operational nozzles of a printhead identified as meeting a failure likelihood criterion, during a print job, and between successive print passes of the printhead, checking operation of the one or more operational nozzles indicated on the vulnerable nozzle map.

Printhead monitoring

A system () is provided having a printer () to print printing liquid onto a web () of media (). The system () has a winding roller () on which to roll the web () of media () after printing. A tensioner () to vary the tension in a portion () of the web () of media () is also provided. The portion () is a portion of web which is being rolled onto the winding roller (). Also provided is controller () to control the tensioner () to vary the tension based on the time taken for the printed printing liquid on the web () of media () to dry.

Variable web tensioning

Example implementations relate to a method to manage printhead operational life; the method comprising firing at least one nozzle of a printhead according to an associated firing parameter to produce a respective drop of print liquid, measuring a parameter associated with the drop of print liquid, and adjusting the firing parameter in response to the measuring to reduce the measured parameter associated with the drop of print liquid on a subsequent firing while maintaining the firing parameter at or above a predetermined parameter limit to maintain print image quality.

Printers and controllers

Disclosed herein is a spittoon assembly for a printing device, a printing device comprising a spittoon assembly, and a method of cleaning a print head using a spittoon assembly. The spittoon assembly comprises a waste receptacle and a spit plate with a receiving surface. The receiving surface is inclined relative to a horizontal direction by an inclination angle when the spittoon assembly is mounted in the printing device. A fluid path extends from the receiving surface to the waste receptacle.

Spittoon assembly for a printing device

An example method comprises operating a drive unit to advance a substrate in a substrate advance direction toward a printing station. At the printing station, a first line is printed onto the substrate. A drive unit is instructed to advance the substrate in the substrate advance direction by a target amount, and a second line is printed onto the substrate. The distance between the first and second lines in a direction perpendicular to the substrate advance direction is calculated and, based on the calculated difference, a tension of the substrate is modified.

Adjusting tension of a substrate

In an example, a printing apparatus includes a controller, wherein the controller may be to compare a historic usage of a first printhead nozzle with a historic usage of a second printhead nozzle which is located on a same printhead as the first nozzle. The controller may be to determine that the historic usage of the first nozzle is higher than the historic usage of the second nozzle, and in response identify a currently operational third printhead nozzle, for which the second nozzle is able to compensate; and turn off the third nozzle, and operate the second nozzle at a higher firing frequency to compensate for the third nozzle.

Printhead nozzle usage

Examples relate to a method to print a print job. The method comprise comparing an operational parameter of the print job with a reference operational parameter and determining to perform a maintenance task during the print job based on at least a result of comparing the operational parameter with the reference operational parameter. If the maintenance task is to be performed, the method further comprises determining a safety area on a printable medium and performing a maintenance task on a printable medium.

Safety zone for a maintenance task

Examples of the present disclosure relate to a calibration method for a printing system. The method comprises printing a diagnostic pattern representative of decap time. The diagnostic pattern comprises the firing of nozzles after an exposure to ambient air during a first predetermined time period to produce a first pattern element and the firing of nozzles after an exposure to ambient air during a second predetermined time period to produce a second pattern element. The method includes scanning the resulting diagnostic pattern with a sensor to collect decap data in a digital form, digitally analyzing the decap data, the digital analysis comprising identifying a quantitative difference between the first and second pattern elements, and modifying a servicing process of the printing system if the quantitative difference passes a predetermined threshold.

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Sant Cugat del Valles, Spain

Andreu Vinets Alonso