The present disclosure relates to an electronic apparatus and an image forming apparatus, and in particular to a calibration process for a touch panel provided in a display unit.
An image forming apparatus, an example of the electronic apparatus, normally includes a display unit having a touch panel function. The touch panel function is involved with the operation of most of the functions of the apparatus, and is hence very frequently used. The touch panels incorporated in the operation unit of the image forming apparatus can be broadly classified into a static capacitance type and a resistive film type, out of which the latter has the longer history of use, and has been employed in various kinds of apparatuses. The advantages of the resistive film touch panel are, for example, that the hardware is inexpensive, that the algorithm for realizing the functions of the touch panel is not complicated, and that the power consumption is low because it is not necessary to employ a high-performance IC or component for the input interface and the control circuit.
However, the touch panel, in particular the resistive film touch panel is intrinsically susceptible to electromagnetic interference (EMI) and humidity, and also the output value of the sensor fluctuates because of a change in temperature and degradation with time, since the resistive film touch panel is controlled by an analog method. In other words, the touch panel erroneous detects the position touched by an operator. Accordingly, calibration has to be performed under a non-input state, to prevent a reference position (datum point) under the non-input state from shifting.
In general, the calibration process for preventing the erroneous detection is designed to utilize a motion sensor so as to perform the calibration when an operator is not present in the vicinity of the apparatus and to suspend the calibration when the operator is close to the apparatus, to thereby prevent a failure of the calibration provoked by the operator by a touch of the touch panel during the calibration (known technique A).