Ink jet recording apparatus and method and program for checking nozzles thereof

A method for checking nozzles of an ink jet recording apparatus, the ink jet recording apparatus comprising:

• a recording head comprising an ink-discharging surface and nozzles configured to discharge ink drops to record an image, the ink-discharging surface including ink-discharging ports of the nozzles;
• a light-emitting element and a light-receiving element disposed opposing each other and substantially close to the ink-discharging surface, the light-receiving element being operable to output a detection signal;
• and
• a reflector provided on the ink-discharging surface and configured to reflect light emitted from the light-emitting element toward the light-receiving element,
• wherein the light-emitting element, the light-receiving element, and the reflector are disposed so that an ink drop normally discharged from one of the nozzles placed at a predetermined position intercepts light reflected by the reflector and then intercepts direct light transmitted from the light-emitting element to the light-receiving element,
• the method comprising the steps of:
• driving the nozzle;
• first checking whether the nozzle discharges an ink drop on the basis of change in the detection signal due to interception of the reflected light;
• and
• second checking, in the case where the nozzle discharges an ink drop, whether the nozzle discharges the ink drop in an appropriate direction on the basis of change in the detection signal due to interception of the direct light.

A program for checking nozzles of an ink jet recording apparatus, the ink jet recording apparatus comprising:

• a recording head comprising an ink-discharging surface and nozzles configured to discharge ink drops to record an image, the ink-discharging surface including ink-discharging ports of the nozzles;
• a light-emitting element and a light-receiving element disposed opposing each other and substantially close to the ink-discharging surface, the light-receiving element being operable to output a detection signal;
• and
• a reflector provided on the ink-discharging surface and configured to reflect light emitted from the light-emitting element toward the light-receiving element,
• wherein the light-emitting element, the light-receiving element, and the reflector are disposed so that an ink drop normally discharged from one of the nozzles placed at a predetermined position intercepts light reflected by the reflector and then intercepts direct light transmitted from the light-emitting element to the light-receiving element,
• the program comprising control procedures for performing the steps of:
• driving the nozzle;
• first checking whether the nozzle discharges an ink drop on the basis of change in the detection signal due to interception of the reflected light;
• and
• second checking, in the case where the nozzle discharges an ink drop, whether the nozzle discharges the ink drop in an appropriate direction on the basis of change in the detection signal due to interception of the direct light.