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(3) Print target detector signal noise filter
(a) Settings of IJ Printer built-in print target detector signal noise filter
This filter provides a function that uses CR method to filter the noise constantly generated in print
target detector signals and the noise generated by water drops. For sensor chattering, the sensor
filter function (see "5.6. Setting Print Specifications" in the Instruction Manual) is effective.
● Internal circuit diagram
(b) Settings of print target detector signal noise filter to the outside of the IJ Printer
If the built-in filter cannot eliminate noise, use CR method to add a filter circuit to the outside of the
IJ Printer as shown below.
When R1 is set to 1 kΩ (0.5 W) and C1 to 1 µF/25 V, the time constant t becomes 1 ms, and
elimination of noise of several hundred µs or less can be expected. When you want to eliminate
more noise, add a capacitor in parallel with C1.
[Cautions on adding the CR filter]
● For stable operation of a photocoupler, the constant of R1 should be 1 kΩ or less.
● For C1, use a temperature compensating ceramic capacitor as much as possible. If the
temperature compensating ceramic capacitor cannot be used due to capacitive and physical
dimensions, use a high dielectric ceramic capacitor with good accuracy and temperature
characteristics.
● Place R1 and C1 as close as possible to the IJ Printer.
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