Patent ID: 7500961

Claim:
A liquid injection system comprising a liquid syringe, a liquid injector and a cylinder adapter; the liquid syringe including a cylinder member and a piston member slidably inserted into the cylinder member, and the liquid injector including a cylinder holding mechanism for receiving the cylinder member of the liquid syringe mounted removably thereon and a piston actuating mechanism for relatively moving the piston member with respect to the held cylinder member of the liquid syringe, wherein the liquid injector comprises mount-detecting means, placed at a position to be covered by the cylinder adapter, for detecting contact and separation of the cylinder member when the cylinder member is mounted on and removed from the cylinder holding mechanism, respectively, and wherein the cylinder adapter the allows cylinder holding mechanism to hold the liquid syringe having a size other than the maximum size, and wherein the cylinder adapter comprises an adapter body having an outer surface held by the cylinder holding mechanism and an inner surface holding the cylinder member, and a contact-transfer member supported movably and moved to a position where the contact-transfer member is in contact with the mount-detecting means when the adapter body with the cylinder member mounted thereon is installed in the cylinder holding mechanism.