Patent ID: 7331938

Claim:
A liquid injector for causing a syringe to suck a liquid from a liquid tank and inject the liquid into a patient, the syringe having a cylinder member and a piston member inserted slidably into the cylinder member, comprising: a patient tube having a leading end connected to the patient; a syringe tube having a trailing end connected to the syringe; a tank tube having a trailing end connected to the liquid tank; a tube connecting means for connecting a trailing end of the patient tube, a leading end of the syringe tube, and a leading end of the tank tube; a syringe drive mechanism for relatively moving the cylinder member and/or the piston member to cause the syringe to suck and inject the liquid; a connection switch mechanism for switching between a suck state in which the patient tube is blocked and the syringe tube is connected to the tank tube and an injection state in which the tank tube is blocked and the syringe tube is connected to the patient tube; an interlock control means for interlocking operation of the syringe drive mechanism and operation of the connection switch mechanism; and an attachment tube having a trailing end connected to a solution injector for injecting a solution into the patient, tube attaching means for attaching a leading end of the attachment tube to the patient tube, and an attachment block mechanism for pressing and blocking the attachment tube to freely open or close the attachment tube, wherein the interlock control means causes the attachment block mechanism to release the blocking only when the connection switch mechanism blocks the patient tube.