Abstract: Examples described herein relate to system and methods consistent with the disclosure. For instance, the imaging system comprises a tray to receive print media, a first sensor to detect a first printing event in the imaging system, a second sensor to detect a second printing event in the imaging system, and a processing resource to determine if the first sensor detected a first printing event, based on the first sensor detecting print media reaching or dropping below a threshold level in the tray, set a logic state based on determining if the first sensor detected the first printing event, maintain the set logic state responsive to the determination that the first sensor detected the first printing event until the second printing event is detected by the second sensor.

Abstract: An apparatus including an illuminator to emit light on a media to be printed on is provided. The apparatus also includes an optical sensor disposed proximate to the illuminator to detect an amount of reflected light. In addition, the apparatus includes a processor to control the illuminator and the optical sensor. The processor is to calibrate the illuminator to determine a first brightness level for high sensitivity at the optical sensor. The processor is to calibrate the illuminator to determine a second brightness level iteratively based on a signal to noise ratio. The processor is to compare the second brightness level with the first brightness level to determine whether to proceed with detection of an edge of the media using the second brightness level.

Abstract: Techniques for controlling assessment of storage height are described. In an example, a device includes an optical transducer and a light source. The optical transducer generates a signal corresponding to light received from the light source. Based on the signal, brightness of the light source may be controlled.

Abstract: Examples relating to determining stack height in imaging devices are described herein. According to one example, an imaging device includes an input roller assembly to transport a print medium towards an image-forming assembly of the imaging device. The input roller assembly can include a pinch roller for drawing the print medium from a media stack. The imaging device further includes a pressure plate movably coupled to a body portion of the imaging device and biased towards the pinch roller. The pressure plate may hold the media stack between itself and the pinch roller and is movable by a first distance from a neutral position when the media stack is there between. The first distance is measured from a fixed point to a measurement region on the pressure plate and can indicate an instantaneous stack height of the media stack.

Abstract: In one example, a printing device may include a first motor to transition a carriage between a first position and a second position, the carriage to exert a force on a gate shifter as the carriage transitions between the first position and the second position, the gate shifter to transition between an open position and a closed position in response to the exerted force of the carriage, and a feed swingarm to transition between a first side and a second side of the gate shifter when the gate shifter is in the open position.

Abstract: An apparatus including an illuminator to emit light on a media to be printed on is provided. The apparatus also includes an optical sensor disposed proximate to the illuminator to detect an amount of reflected light. In addition, the apparatus includes a processor to control the illuminator and the optical sensor. The processor is to calibrate the illuminator to determine a first brightness level for high sensitivity at the optical sensor. The processor is to calibrate the illuminator to determine a second brightness level iteratively based on a signal to noise ratio. The processor is to compare the second brightness level with the first brightness level to determine whether to proceed with detection of an edge of the media using the second brightness level.

Abstract: A print agent vessel is disclosed that comprises a circuit, the circuit comprising a first electrically conductive portion to couple to a first terminal of a printing device, a second electrically conductive portion to couple to a second terminal of the printing device, and an electrically conductive component capacitively coupled to the first electrically conductive portion. The circuit has a variable capacitance that is indicative of a parameter of the component.

Abstract: A print agent vessel is disclosed that comprises a circuit, the circuit comprising a first electrically conductive portion to couple to a first terminal of a printing device, a second electrically conductive portion to couple to a second terminal of the printing device, and an electrically conductive component capacitively coupled to the first electrically conductive portion. The circuit has a variable capacitance that is indicative of a parameter of the component.

Abstract: Examples relating to determining stack height in imaging devices are described herein. According to one example, an imaging device includes an input roller assembly to transport a print medium towards an image-forming assembly of the imaging device. The input roller assembly can include a pinch roller for drawing the print medium from a media stack. The imaging device further includes a pressure plate movably coupled to a body portion of the imaging device and biased towards the pinch roller. The pressure plate may hold the media stack between itself and the pinch roller and is movable by a first distance from a neutral position when the media stack is there between. The first distance is measured from a fixed point to a measurement region on the pressure plate and can indicate an instantaneous stack height of the media stack.

Abstract: Examples techniques to control execution of print commands are described. In an example, a print command indicative of markings to be on a medium is received at an image rendering device. A number of ink droplets to be ejected from nozzles of the image rendering device to form the markings on the medium is determined. A thickness that the medium will have upon the markings being formed is determined based on the number of ink droplets to be ejected from the nozzles. The print command is executed based on the estimated thickness.

Abstract: A printer is operated to determine an attribute of a field of view of the scan sensor. A calibration test pattern is determined based on the field of view (e.g., size of the field of view relative to dimension of individual bar in pattern).

Abstract: A printer is operated to determine an attribute of a field of view of the scan sensor. A calibration test pattern is determined based on the field of view (e.g., size of the field of view relative to dimension of individual bar in pattern).

Abstract: In one embodiment, a stated reflectance identifier for a media to be printed on during fulfillment of a print job is received. Utilizing an optical sensor and an illuminator, a measurement is taken of light from the illuminator reflected off the media. The measurement is compared to a stored average brightness value. Responsive to determining the measurement is within a range of the average value, the average value is adjusted to include the measurement, and printing on the media is caused according to the job. Responsive to determining the measurement is outside the range, the measurement is compared to a database associating brightness measurements and reflectance identifiers to determine an estimated reflectance identifier for the media. The estimated identifier is sent to a user and the user is prompted to perform a correction event. The media is printed on according to the job.

Abstract: A printer includes an energy storage device and a charger for charging the energy storage device and for providing a first DC voltage. The printer includes a first DC-to-DC voltage converter for converting the first DC voltage to a second DC voltage. The printer includes first printer electronics powered by the second DC voltage.

Abstract: In one embodiment, a stated reflectance identifier for a media to be printed on during fulfillment of a print job is received. Utilizing an optical sensor and an illuminator, a measurement is taken of light from the illuminator reflected off the media. The measurement is compared to a stored average brightness value. Responsive to determining the measurement is within a range of the average value, the average value is adjusted to include the measurement, and printing on the media is caused according to the job. Responsive to determining the measurement is outside the range, the measurement is compared to a database associating brightness measurements and reflectance identifiers to determine an estimated reflectance identifier for the media. The estimated identifier is sent to a user and the user is prompted to perform a correction event. The media is printed on according to the job.

Abstract: A printer includes an energy storage device and a charger for charging the energy storage device and for providing a first DC voltage. The printer includes a first DC-to-DC voltage converter for converting the first DC voltage to a second DC voltage. The printer includes first printer electronics powered by the second DC voltage.

Abstract: A printer accessory module for coupling to a printer to increase its printing capacity. The printer accessory module includes an auxiliary media module for storing and supplying printer media; and an auxiliary ink supply station for storing and supplying ink to the printer. The auxiliary ink supply station is connected to the printer by a ink delivery conduit system.

Abstract: A vending machine capable of refilling used ink cartridges as well as dispensing filled ink cartridges is closed. The vending machine includes at least one cartridge receptacle for receiving an ink cartridge, a user interface, a display unit, a nozzle health check module, a printhead servicing module, an ink reservoir, an ink refilling unit, a compartment containing new ink cartridges, a compartment containing filled, second-hand ink cartridges, and a recycle compartment for receiving discarded ink cartridges. The user is presented by the display unit with the option of (a) refilling a used cartridge, (b) purchasing a filled cartridge, or (c) returning a used cartridge in exchange for a purchase rebate or a discount voucher. When the user selects the option of refilling, the vending machine executes a refilling subroutine which includes checking the nozzle health.

Abstract: A vending machine capable of refilling used ink cartridges as well as dispensing filled ink cartridges is closed. The vending machine includes at least one cartridge receptacle for receiving an ink cartridge, a user interface, a display unit, a nozzle health check module, a printhead servicing module, an ink reservoir, an ink refilling unit, a compartment containing new ink cartridges, a compartment containing filled, second-hand ink cartridges, and a recycle compartment for receiving discarded ink cartridges. The user is presented by the display unit with the option of (a) refilling a used cartridge, (b) purchasing a filled cartridge, or (c) returning a used cartridge in exchange for a purchase rebate or a discount voucher. When the user selects the option of refilling, the vending machine executes a refilling subroutine which includes checking the nozzle health.

Abstract: A printer accessory module for coupling to a printer to increase its printing capacity. The printer accessory module includes an auxiliary media module for storing and supplying printer media; and an auxiliary ink supply station for storing and supplying ink to the printer. The auxiliary ink supply station is connected to the printer by a ink delivery conduit system.