Recording apparatus and predischarge control method

A predischarge control method used for a recording apparatus provided with an ink jet recording head, a cap covering a discharge port surface of said ink jet recording head having discharge ports formed thereon, being capable of receiving ink discharged from said discharge ports, predischarge means for pre-discharging ink from said ink jet recording head to an inside of said cap at designated time intervals aside from recording operation, and idle suction means for exhausting ink received by said cap to an outside of said cap, comprising the following:

• an accumulating step of accumulating an amount of ink consumption by said predischarge;
• a first comparison step of comparing the amount of ink consumption accumulated in said accumulating step with a first threshold value per predischarge;
• a first predischarge control step of controlling to reduce the amount of ink discharge for predischarge to follow in accordance with a comparison result in said first comparison step;
• a second comparison step of comparing the amount of ink consumption accumulated in said accumulating step with a second threshold value larger than the first threshold value per predischarge of the amount of ink discharge reduced in said first predischarge control step;
• a predischarge prohibition step of controlling to prohibit predischarge operation in accordance with the comparison result in said second comparison step;
• and
• a second predischarge control step of controlling to resume predischarge to follow after the completion of recording operation in accordance with the period of time defined in said predischarge operation prohibition step of prohibiting predischarge operation, and to increase the amount of ink consumption for the predischarge.

A method for controlling an ink jet recording apparatus for performing a recording operation by discharging ink from a discharge port, said method comprising:

• a step of preliminarily discharging ink from said discharge port separately from said recording operation;
• a step of accumulating an ink discharge amount caused in said preliminary discharge step;
• a first comparison step of comparing the ink discharge amount accumulated in said accumulating step with a first threshold value;
• a preliminary discharge control step of controlling to reduce the ink discharge amount in following preliminary discharge in accordance with a comparison result in said first comparison step;
• a second comparison step of comparing the ink discharge amount accumulated in said accumulating step with a second threshold value which is larger than said first threshold value after said preliminary discharge control step;
• and
• a preliminary discharge inhibiting step of inhibiting the following preliminary discharge in accordance with the comparison result in said second comparison step.

A method for pre-discharging ink not concerning recording from a discharge port of an ink jet recording head for discharging ink to record, said method comprising:

• a first step of pre-discharging ink from the discharge port of the ink jet recording head;
• a second step of pre-discharging ink from the discharge port of the ink jet recording head with a discharge amount smaller than a discharge amount of ink in succeeding predischarge when the discharge amount of ink in the predischarge at the first step reaches a first threshold value;
• and
• a third step of pre-discharging ink from the discharge port of the ink jet recording head by changing a time interval for succeeding predischarge when, with a discharge amount smaller than a discharge amount of ink in succeeding predischarge, the discharge amount of ink in the predischarge at the first and second steps reaches a second threshold value.