Abstract: A power management technique for a printer includes detecting a change in a state of operation of a printing device. The amount of power available to operate all functions of the printing device is calculated. Next, power is delivered to specified functions of the printing device based on the calculated amount of power available, wherein the specified functions are a subset of all functions of the printing device. Then, it is determined whether the specified functions operate correctly.

Abstract: An image forming apparatus comprising a thermal printhead and a controller. The thermal printhead has heating elements. The controller is to receive an indicated print mode corresponding to a type of thermal medium to be used, determine a power profile based on the indicated print mode, and control power to be delivered to the thermal printhead based on the determined power profile.

Abstract: Example implementations relate to adjust sharpness parameters. In some examples, a printing device can include a processing resource and a memory resource storing non-transitory machine-readable instructions to cause the processing resource to receive print data comprising color channels corresponding to print pixels to be formed on a multi-layer thermally activated print medium, determine a characteristic of a corresponding layer of the multi-layer thermally activated print medium for color channels of the received print data, adjust sharpness parameters of the color channels based on the determined characteristic of the corresponding layer of the multi-layer thermally activated print medium, and cause a print head of the printing device to apply thermal energy to an area of the multi-layer thermally activated print medium including the print pixels using the adjusted sharpness parameters.

Abstract: In one example in accordance with the present disclosure, a printing device is described. The printing device includes a single thermal printhead that includes an array of heating elements. The array of heating elements are selectively powered to form content on both sides of thermal media passing thereby. Different sides of the thermal media have thermal dye layers with different activation sensitivities. The printing device also includes a media transport system to move the thermal media by the single thermal printhead. A controller of the printing device generates printed content on both sides of the thermal media in a single pass by powering the single thermal printhead based on both content to be formed on a first side and content to be formed on a second side.

Abstract: In some examples, dithering based color conversion may include ascertaining an input color value. Based on conversion of the input color value to an output color space representation, a set of nodes that are to be analyzed to control operation of a printer may be determined. Based on a position of the input color value from each node of the set of nodes, a corresponding probability associated with each node of the set of nodes may be determined. Further, the operation of the printer may be controlled based on the determined probability associated with each node of the set of nodes.

Abstract: An example of apparatus to align media. The apparatus includes a printer assembly to form markings a first side of a media. The apparatus also includes a sensor to detect a backside pattern on each pass at multiple locations. The apparatus includes a processor in communication with the sensor. The processor is to compare the backside pattern measured on multiple passes to determine offset amounts. The apparatus also includes a controller to adjust the media relative to the printer assembly based on the offset values.

Abstract: In some examples, luminance-biased sharpening for thermal media printing may include converting an input image to a grayscale luminance representation. For each pixel of a plurality of specified pixels of the converted input image, a sharpening lightness value may be determined. Further, a ratio of the sharpening lightness value to a corresponding original lightness value may be determined. A resulting sharpened pixel may be determined by applying a corresponding value of the determined ratio to each of the specified pixels. A dark correction factor may be applied to the resulting sharpened pixels that are darkened and a light correction factor may be applied to the resulting sharpened pixels that are lightened. Based on application of the dark correction factor and the light correction factor, a sharpened output image corresponding to the input image may be generated.

Abstract: In some examples, simultaneous color development for thermally activated print media may include ascertaining an input image that is to be printed using a thermal printhead. Colors that are to be printed may be determined for a plurality of specified pixels of the input image. A plurality of frequencies may be clustered to print each color of the determined colors. Based on the clustered plurality of frequencies, operation of a printhead that is to print the plurality of specified pixels may be controlled.

Abstract: In some examples, dithering based color conversion may include ascertaining an input color value. Based on conversion of the input color value to an output color space representation, a set of nodes that are to be analyzed to control operation of a printer may be determined. Based on a position of the input color value from each node of the set of nodes, a corresponding probability associated with each node of the set of nodes may be determined. Further, the operation of the printer may be controlled based on the determined probability associated with each node of the set of nodes.

Abstract: In some examples, luminance-biased sharpening for thermal media printing may include converting an input image to a grayscale luminance representation. For each pixel of a plurality of specified pixels of the converted input image, a sharpening lightness value may be determined. Further, a ratio of the sharpening lightness value to a corresponding original lightness value may be determined. A resulting sharpened pixel may be determined by applying a corresponding value of the determined ratio to each of the specified pixels. A dark correction factor may be applied to the resulting sharpened pixels that are darkened and a light correction factor may be applied to the resulting sharpened pixels that are lightened. Based on application of the dark correction factor and the light correction factor, a sharpened output image corresponding to the input image may be generated.

Abstract: In some examples, continuous frequency based print pipeline generation may include ascertaining an input image that is to be printed. For a specified pixel of the input image, a first frequency and a second frequency that respectively correspond to first and second colors may be determined. Based on the first frequency and the second frequency, an intermediate frequency that is to be generated to produce an intermediate color relative to the first and second colors may be determined. The intermediate frequency may be converted to discrete pulses. Operation of a printhead that is to print the specified pixel may be controlled based on the discrete pulses.

Abstract: Example implementations relate to adjust sharpness parameters. In some examples, a printing device can include a processing resource and a memory resource storing non-transitory machine-readable instructions to cause the processing resource to receive print data comprising color channels corresponding to print pixels to be formed on a multi-layer thermally activated print medium, determine a characteristic of a corresponding layer of the multi-layer thermally activated print medium for color channels of the received print data, adjust sharpness parameters of the color channels based on the determined characteristic of the corresponding layer of the multi-layer thermally activated print medium, and cause a print head of the printing device to apply thermal energy to an area of the multi-layer thermally activated print medium including the print pixels using the adjusted sharpness parameters.

Abstract: An example of apparatus to align media. The apparatus includes a printer assembly to form markings a first side of a media. The apparatus also includes a sensor to detect a backside pattern on each pass at multiple locations. The apparatus includes a processor in communication with the sensor. The processor is to compare the backside pattern measured on multiple passes to determine offset amounts. The apparatus also includes a controller to adjust the media relative to the printer assembly based on the offset values.

Abstract: An example system for a thermal printing device may comprise a printhead comprising a heat source, where the printhead is to transmit heat from the heat source onto a thermally activated print medium to form markings on a plurality of regions of the thermally activated print medium to form a pixel, and a controller to determine a plurality of voltage pulse patterns prior to formation of the markings on the plurality of regions, determine which of the plurality of regions the plurality of voltage pulse patterns are to activate prior to formation of the markings on the plurality of regions, where the plurality of regions comprise regions with overlapping color layers onto which markings are to be formed with an individual pulse pattern of the plurality of voltage pulse patterns, and send a voltage pulse pattern information to the printhead.

Abstract: An example of a print media can include a substrate, a removable layer coupled to a surface of the substrate, and an object on a surface of the removable layer, the object including tracking markings to permit determination of a velocity of the print media.

Abstract: Example implementations applying thermal energy to sub-lines. In some examples, a printing device can include a processing resource and a memory resource storing non-transitory machine-readable instructions to cause the processing resource to receive print data about a line to be formed on a thermally activated print medium, divide the line into a plurality of sub-lines, determine a threshold colorant density level of a first sub-line and a third sub-line of the plurality of sub-lines based on the received print data, and cause a print head of the printing device to apply thermal energy to the first sub-line and the third sub-line on the thermally activated print medium using the received print data.

Abstract: In some examples, a system may include a thermal print head including a plurality of print head elements to heat a print medium. The system may include a controller to determine a tri-color tuple of a pixel of an image to be printed; determine an input temperature at a specific print head element, of the plurality of print head element s, printing the pixel on thermal print medium; and determine a voltage pulse pattern for printing the tri-color tuple at the input temperature based on a previously printed pixel.

Abstract: In some examples, luminance-biased sharpening for thermal media printing may include converting an input image to a grayscale luminance representation. For each pixel of a plurality of specified pixels of the converted input image, a sharpening lightness value may be determined. Further, for each pixel of the plurality of specified pixels of the converted input image, a ratio of the sharpening lightness value to a corresponding original lightness value may be determined. Based on the determined ratio, a sharpened output image corresponding to the input image may be generated.

Abstract: Example implementations relate to initiation of a shortage model in a printing device. For example, initiation of a shortage model may include guidance of a page of print media through a printing device by a feedshaft and an upper paper guide, where the page of print media is held by a media control surface. A shortage model may be initiated based on an amount of data to be printed. An ink nozzle may be turned off based on the initiated shortage model.

Abstract: In some examples, luminance-biased sharpening for thermal media printing may include converting an input image to a grayscale luminance representation. For each pixel of a plurality of specified pixels of the converted input image, a sharpening lightness value may be determined. Further, for each pixel of the plurality of specified pixels of the converted input image, a ratio of the sharpening lightness value to a corresponding original lightness value may be determined. Based on the determined ratio, a sharpened output image corresponding to the input image may be generated.