Warming printheads during print passes

A non-transitory computer readable storage medium including executable instructions that, when executed by a processor, cause the processor to:

• determine a drive signal to drive a printhead to each of a series of target temperatures during respective portions of a print pass by the printhead, each of the target temperatures being a greater of a temperature of the printhead caused by printing a quantity of printing fluid to be printed during the respective portion and a predetermined threshold temperature, wherein the drive signal is based on a plurality of heating quantities that are determined before printing the print pass;
• and
• provide the drive signal to warm the printhead to the series of target temperatures while the printhead prints the respective quantities of the printing fluid during the respective portions.

A printing system comprising:

• a printhead including a plurality of heating units to warm the printhead to a series of target temperatures while the printhead prints respective quantities of the printing fluid during respective portions of a print pass;
• and
• a controller to determine a drive signal to drive the printhead to the series of target temperatures, each of the target temperatures being the greater of a temperature of the printhead caused by printing the quantity to be printed during the respective portion and a predetermined threshold temperature, a first target temperature of the series of target temperatures being greater than the threshold temperature, a second target temperature of the series of target temperatures being equal to the threshold temperature.