Image forming system and head moving method

A head moving method to be executed by a controller of an image forming system including:

• a head configured to form an image on a medium by ejecting a liquid;
• a head moving mechanism configured to move the head along a head movement direction between an image formation area at one end in the head movement direction and an escape area at other end in the head movement direction, the head moving mechanism including:
• a carriage supporting the head;
• a stepping motor;
• a power transmitter which is connected to the carriage and the stepping motor and which is configured to transmit a power of the stepping motor to the carriage;
• and
• a first sensor and a second sensor each configured to sense that the head is located in the image formation area, and each configured to be in an OFF state in a case where the head is located in the escape area;
• and
• the controller electrically connected to the stepping motor, the first sensor, and the second sensor,
• the head moving method comprising:
• in a case where the head is moved from the escape area to a first position in the image formation area, rotate the stepping motor in one direction until the head arrives at a first preliminary position at which the first sensor turns from the OFF state to an ON state, so as to move the head at a first velocity toward the one end, and rotate the stepping motor by a step number S1 in the one direction from a point in time at which the head has arrived at the first preliminary position, so as to move the head to the first position at a second velocity smaller than the first velocity, by the controller;
• in a case where the head is moved from the escape area to a second position, in the image formation area, different from the first position, rotate the stepping motor in the one direction until the head arrives at a second preliminary position at which the second sensor turns from the OFF state to the ON state, so as to move the head at the first velocity toward the one end, and rotate the stepping motor by a step number S2 in the one direction from a point in time at which the head has arrived at the second preliminary position, so as to move the head to the second position at the second velocity, by the controller;
• and
• in a case where the head is moved from the escape area to a third position, in the image formation area, different from the first position and the second position, rotate the stepping motor in the one direction until the head arrives at a third preliminary position at which the first sensor having turned to the ON state by the head having arrived at the first preliminary position turns to the OFF state again, so as to move the head at the first velocity toward the one end, and rotate the stepping motor by a step number S3 in the one direction from a point in time at which the head has arrived at the third preliminary position so as to move the head to the third position at the second velocity, by the controller.