Abstract: A dot matrix printer and motor having hammers forming in part a hammerbank and a counterbalance mechanically linked to the hammerbank with a link to the position of the motor. The motor includes coils positively driven and then negatively driven after current in the coils has at least partially decayed. The current in the coils is allowed to decay further after negatively driving the coil. The motor coils are connected to an H bridge having transistors which can be formed in a full H bridge or half bridge. A controller switches the transistors to cause negative and positive flow through the H bridge for positive current flow from a reference level to an upper reference level, and a decay of current within the coils to an intermediate reference. The coils are then driven with a negative current from the intermediate reference level to a second intermediate reference level afterwhich the current within the coils decays to a lower or initial reference level.

Abstract: A label printer having a stepping motor and the ability to dynamically accurately control longitudinal label registration as a function of steps of the stepping motor. The effective length of the steps moving the labels between a known point prior to the printhead and the printhead are monitored and the number of steps actually used to move the labels between the known point and the printhead are adjusted as a function of changes in the effective step length. In one embodiment, a sensor counts the steps between consecutive labels or averages a number of labels to determine the effective step length. In another embodiment, a sensor detects the start of label and start of printing on the label and the step distance between the two is used to determine the effective step length.

Abstract: A method and apparatus proecsses a dot image formed of a plurality dots, each dot having a density level. In the method and appratus, a dot pattern is extracted from the dot image, which dot pattern being formed of an observation dot and dots surrounding the observation dot, it is tdetermining, based on comparison between the extracted dot pattern and predetermined reference patterns, whether or not the observation dot in the dot pattern is either a dropout dot or a projection dot, a density level of the observation dot is changed to a first density level corresponding to the dropout dot when it is determined that the observation dot is the dropout dot, and a density level of the observation dot is changed to a second density level corresponding to the projection dot when it is determined that the observation dot is the projection dot.

Abstract: In a printing device employing a solenoid for driving a printing hammer, provided are switching member for ON/OFF operating electric current flowing through the solenoid coil, voltage generating member for generating voltage in accordance with the electric current, converting member for converting the generated voltage to a digital value, chopping member for comparing the converted digital value with a predetermined comparison value, while for turning on the switching member when the converted value is smaller than the predetermined comparison value and turning off the switching member when the converted value is larger than the predetermined comparison value, detecting member for detecting voltage relating to a driving operation of said solenoid, and controlling member for controlling the predetermined comparison value so as to be varied in an amount based upon the detected voltage. Thus, the current flowed through the solenoid is controlled so as not to be largely varied.