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A syringe pump has a pusher (86) that pushes in the plunger (81)
of a syringe (8) to dispense medication. A pivoted barrel size sensor
arm (201) engages the syringe barrel (82) at one end (203) and carries
three flags (207 208 and 209) at the other end (205), which move
across three sensors (217 218 and 219) such that each sensor can
change from a first state to a second state and back to a first
state as the arm moves, to provide nine different size outputs.
A pressure sensor is connected to an intermediate portion of an
air pipe that connects a syringe pump to a spotting nozzle of a
spot fixing device. The syringe pump consists of a syringe and a
plunger that slides up and down in the syringe, for sucking and
discharging a liquid through the spotting nozzle. While moving the
plunger in the same work range as in the actual sucking discharging
operation, internal pressure of the syringe pump is measured by
the pressure sensor, and derivative values of the measure pressure
are obtained by differentiation. The derivative values are compared
with threshold values, to detect disorder of the syringe pump, such
as leakage caused by insufficient air-tightness of the syringe to
the plunger or some defect in the plunger.
It is an object of the present invention to provide a multiple-syringe-pump
driving apparatus having superior liquid discharging and drawing-up
precision. A syringe-pump driving apparatus of the present invention
is used for controlling discharge from and drawing-up into a plurality
of syringe pumps interconnected in parallel. The syringe-pump driving
apparatus 10 comprises: a syringe holder 18 for supporting syringes
14a to 14h of the plurality of syringe pumps 12a to 12h so as to
be arranged in parallel; a plunger holder 20 for supporting plungers
16a to 16h contained in the syringes 14a-14h so as to be arranged
in parallel; three or more drive screws 24-1 to 24-3 for moving
the plunger holder 20 and the syringe holder 18 relative to each
other in a straight line in a syringe axial direction 30; and one
or a plurality of motors 26 serving as a source of motive power
for the drive screws 24-1 to 24-3. The three or more drive screws
24-1 to 24-3 are connected to the syringe holder 18 or the plunger
holder 20 at three or more driving points to transmit motive power
to the syringe holder 18 or the plunger holder 20 via the three
or more driving points.
Travel amount detecting means 10 for detecting the travel amount
of a plunger 4b, distal end detecting means 11 for detecting the
fact that the plunger 4b has moved to the distal end of a syringe
4 distance measuring means for measuring the travel distance of
the plunger 4b, input means 13 capable of inputting the capacity
of the syringe 4 and storage means 14 capable of storing the measured
travel distance of the plunger 4b and the input capacity of the
syringe 4 are provided. The control means 16 selects the travel
distance of the plunger 4b corresponding to the input capacity from
the storage means 14 and controls the injection of a chemical solution
in the syringe 4 accomplished via plunger pressing means based on
the travel distance of plunger and the capacity of syringe. Thereby,
a syringe pump can be provided which can be used for a syringe that
is sold newly or a syringe with a dimension changed by design change
or remodeling.
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