Image forming system
An image forming system ( 100 ) is provided with plural image forming apparatuses ( 200 ) that form images on can bodies ( 10 ), a can-body supply mechanism ( 300 ) that supplies can bodies ( 10 ) to the plural image forming apparatuses ( 200 ) successively, and a can-body discharge mechanism ( 400 ) that discharges the can bodies ( 10 ) on which images have been formed by the image forming apparatuses ( 200 ). Each of the image forming apparatuses ( 200 ) receives, at a can-body receiving position ( 1 C), can bodies ( 10 ) supplied by the can-body supply mechanism ( 300 ). Each of the image forming apparatuses ( 200 ) also discharges, at a can-body discharging position ( 1 D), can bodies ( 10 ) on which images have been formed. The can-body receiving positions ( 1 C) and the can-body discharging positions ( 1 D) are arranged more to the inner side than a circular virtual line ( 1 B) that passes through the centers of the image forming apparatuses ( 200 ).
1. An image forming system comprising:
a first image forming portion that forms an image on an outer circumferential surface of a can body rotating in a circumferential direction;
a first obtaining unit that obtains information related to rotation angle of the can body when image formation by the first image forming portion is started;
a second image forming portion that forms an image on the can body rotating in the circumferential direction after the image is formed on the can body by the first image forming portion;
a second obtaining unit that obtains information related to rotation angle of the can body when image formation by the second image forming portion is started;
a data storing portion that stores image data of the image formed by the second image forming portion; and
a determination unit that determines a starting position of reading of image data used by the second image forming portion based on the information related to the rotation angle obtained by the first obtaining unit and the information related to the rotation angle obtained by the second obtaining unit,
wherein the second image forming portion forms an image on the outer circumferential surface of the can body rotating in the circumferential direction by use of the image data successively being read from the starting position of reading determined by the determination unit.
2. The image forming system according to claim 1 , wherein the determination unit determines the starting position of reading based on an angle difference, which is a difference between a rotation angle specified by the information related to the rotation angle obtained by the first obtaining unit and a rotation angle specified by the information related to the rotation angle obtained by the second obtaining unit.
3. The image forming system according to claim 1 , further comprising:
a rotating unit that rotates the can body in the circumferential direction,
wherein the rotating unit rotates the can body with a constant speed, without increasing or decreasing the rotation speed of the can body, during a period from starting of image formation by the first image forming portion to completion of image formation by the second image forming portion.
4. The image forming system according to claim 1 , wherein the first image forming portion and the second image forming portion form an image on the outer circumferential surface of the can body by ejecting ink from above the can body in a lying state.
5. The image forming system according to claim 1 , wherein
the first image forming portion and the second image forming portion are arranged at positions different from each other,
the image forming system comprises a moving unit that moves the can body to pass through each of the first image forming portion and the second image forming portion while rotating the can body in the circumferential direction, and
the can body, which moves to pass through each of the first image forming portion and the second image forming portion while rotating in the circumferential direction, performs the movement while rotating with a constant speed without increasing or decreasing the rotation speed thereof.