Abstract: In a black character detection processing, RGB data read from a line buffer is converted into YIQ data. For a subject pixel, a subject area centered on the subject pixel is set, and a judgment pixel that has the lowest brightness in the subject area is set. Then, a judgment area is set as being centered on the judgment pixel. If the absolute values of the averages of chroma components I and Q in the judgment area are both less than the corresponding thresholds T1 and T2, the subject pixel is determined as being an achromatic pixel. Black codes are added to fine-line pixels and edge pixels if the fine-line pixels and edge pixels are determined as being achromatic. Thus, the fine-line pixels and edge pixels can be specified as to be printed in black monochromatic ink. Therefore, black character or similar fine-line or edge part images can be outputted with high quality.

Abstract: According to a fine line detection processing, when for a subject pixel to be subjected to the fine line detection processing, a 3×3 matrix area centered on this subject pixel is set as a subject area. Point values “0” to “8” are assigned to the matrix elements constituting this 3×3 matrix subject area. Then, three pixels with the first, second, and third lowest brightness values are extracted from the subject area. When the total point value of the three extracted pixels is equal to “12”, the extracted pixels are determined as being in a connected state. Then, an intermediate value is calculated from the minimum and maximum values of brightness (Y) of pixels in the subject area. When the number of pixels with a brightness (Y) value smaller than the intermediate value is less than 4, the subject pixel is determined as being a fine-line pixel. A fine-line code is added to the subject pixel that is determined as being a fine-line pixel.

Abstract: The invention provides an image reading apparatus that produces a precise image of an original document to prevent the read image from having distortion or irregular density, by driving a DC motor, which drives an image reading unit in a scanning direction, at a constant speed suitable for a document to be read. In addition, the image reading apparatus prevents position errors or misalignment at the start of the image reading, or at a restart of the image reading after the image reading is paused. A speed control circuit provides feedback to a DC motor to synchronize a time interval detected by a pulse interval detecting circuit with a time interval set by an interval setting register, so that the DC motor is operated at a constant speed. A counter counts the number of signals output from an encoder. After the speed of the DC motor is stabilized, a timing of signals output from a CCD drive unit to the image reading unit is synchronized with a timing of the signals generated by the encoder.

Abstract: To minimize an occurrence of run-out of power in a battery in the middle of communication and an occurrence of a communication error caused thereby. The residual amount of power in the battery is detected. Communication is enabled only when the residual amount of power in the battery exceeds a predetermined amount. Information relative to the residual amount of power in the battery is displayed to allow an operator to recognize the residual amount of power in the battery. Further, information relative to the residual amount of power in the battery is transmitted to the transmission side so that information in excess of the residual amount of power in the battery on the receiving side is not transmitted to the receiving side.