Image forming apparatus

An image forming apparatus comprising:

• a sub-scanning carriage configured to move a recording medium in a conveyance direction;
• a first carriage configured to:
• move in a main scanning direction orthogonal to the conveyance direction;
• and
• discharge a liquid onto the recording medium to print a first image on the recording medium;
• a second carriage configured to:
• move in the main scanning direction;
• and
• discharge another liquid different from the liquid onto the first image on the recording medium to print a second image on the first image of the recording medium;
• and
• circuitry configured to:
• cause the second carriage to print second image after causing the first carriage to finish printing the first image, to execute a first print sequence;
• cause the second carriage to print second image while causing the first carriage to print the first image, to execute a second print sequence;
• calculate a drying time of the liquid to form the first image by the first carriage;
• determine whether to execute the second print sequence based on the drying time;
• cause the first carriage and the second carriage to execute the second print sequence when the circuitry determines to execute the second print sequence;
• cause the first carriage and the second carriage to execute the first print sequence when the circuitry determines not to execute the second print sequence;
• calculate the drying time of the liquid that forms the first image to be printed on a portion of the recording medium;
• calculate a movement time of the recording medium moved by the sub-scanning carriage from a finishing position at which the first carriage finishes printing the first image on the portion of the recording medium to a start position at which the second carriage starts printing the second image onto the first image printed on the portion of the recording medium;
• execute the second print sequence when the drying time is equal to or less than the movement time;
• execute the first print sequence when the drying time is more than the movement time;
• print the first image on the portion of the recording medium in which a blank portion is formed other than the portion of the recording medium;
• and
• calculate the movement time of the recording medium moved through the blank portion in the conveyance direction by the sub-scanning carriage based on a size of the blank portion to shorten the movement time according to an increase in the size of the blank portion.