Abstract: A testable assembly that includes a plurality of recording elements such as LED's for burn-in testing or the like is described. The assembly includes LED chip arrays, integrated circuit driver chips and spreader boards for distributing signals to the driver chips. The spreader boards each include a minimum number of test pads for providing power and control signals during burn-in testing. The driver chip is designed for grey level recording using a plurality of data bits to control the pixel recording period for each LED. Burn-in testing is accomplished without even provision for real data signals. Rather, pseudo data signals are generated internally by a weak current pull-up circuit associated with each data input lead of the driver chip. This pull-up circuit is easily overridden by normal data signals during normal printhead operation. In addition to power signals, an exposure clock and latch signal are provided at the input pad for varying power and duty signal to the LED's during testing.

Abstract: A thermal print head modulator (300) for generating modulation signals for printing a halftone dot (145) whose size corresponds to a data value (205) represented by a plurality of bits. The modulator (300) includes a programmable look-up table (235) containing modulation values (236) that are selectable by control circuitry (245). By storing modulation values (236) in a pre-determined pattern and selecting each value sequentially for comparison with each data value (205), the modulator (300) is compatible with both pulse count modulation and partial pulse modulation having any number of designated partial pulse bits in the data value (205).

Abstract: A non-impact printer apparatus is described that includes a recording head having a plurality of recording elements such as LED's for recording on a recording medium. A plurality of driver chips are provided on the head and each includes a plurality of current driving channels for selectively driving a plurality of recording elements in accordance with respective image data signals. The driver chips each further include an extra current driving channel not associated with a recording element for generating a current related to that sent to said recording elements. Monitoring of the current in the extra channel is provided to permit for changes of current to the recording elements and/or corrected image data to provide fine tuned control over uniformity of the recording elements.