| 摘要 |
PROBLEM TO BE SOLVED: To detect ink end more inexpensively and accurately through a simple processing by providing the detection process with a step for removing the maximum value from a plurality of peak values and/or removing the minimum value from a plurality of bottom values. SOLUTION: In correspondence with the rising edge 202 of an input waveform 201, a digital value corresponding to the peak value 207 of an ink end detection signal 204 detected by an antenna electrode and the value of working point 206 are determined and then the amplitude 208 of the ink end detection signal 204 is determined by subtracting the value of working point 206 from the digital value. Similarly, the digital values of a working point 209 and a peak value 210 are detected in correspondence with the rising edge 203 of the input waveform and the amplitude 211 of the ink end detection signal 204 is determined by subtracting the peak value 210 from the value of the working point 209. Subsequently, maximum and minimum values are removed from four amplitude values thus determined and the average value thereof is employed as an ink end detection signal. |
