Epson Stylus 1500, Service Manual

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HP sensor A photocoupler-type home position (HP) sensor is attached to the surface of the
printer mechanism to detect the carriage home position. A HIGH level signal from
this sensor indicates the carriage is in the home position.
Front PE
sensor A mechanical switch paper end (PE) sensor is built into the printer mechanism to
determine if there is paper in the printer. If this sensor is CLOSED, it indicates no
paper is loaded.
Rear PE
sensor A mechanical switch PE sensor is built into the rear paper guide to determine if
there is paper in the printer. If this sensor is CLOSED, it indicates no paper is
loaded.
Release
sensor A mechanical switch release sensor is built into the left side frame of the printer
mechanism to determine whether the release lever is switched to friction or push
tractor mode. If this sensor is CLOSED, it indicates tractor mode is selected.
Black ink
cartridge
sensor A mechanical switch sensor for the black ink cartridge is built into the ink cartridge
holder in the printer mechanism to determine if the black ink cartridge is installed.
If this sensor is CLOSED, it indicates that the cartridge is installed.
Black ink
out sensor A mechanical switch sensor for ink out in the black cartridge is built into the ink
cartridge holder in the printer mechanism to determine whether the black ink
supply is empty or low. This sensor is used along with the black ink cartridge
sensor signal, as shown in the following illustration:
Thermistor A thermistor is attached to the black ink printhead driver board to monitor the
temperature, using thermistor resistance values (approximately 10 K
Ω
at 77
°
F or
25
°
C). The CPU changes the printhead drive signal’s pulse width (change pulse
width) based on the temperature level.
DE sensor A mechanical switch disengage (DE) sensor is built into the printer mechanism to
determine whether the disengage gear is on the paper feed (PF) side or the pump
side. If this sensor is CLOSED, it indicates the disengage gear is on the PF side.
Color ink
cartridge
sensor A mechanical switch color ink cartridge sensor is built into the color cartridge
holdre to determine if the color ink cartridge is installed. A HIGH level signal from
this sensor indicates that the cartridge is installed.
Color ink
out sensor Data regarding the consumption of color ink is stored in the EEPROM. If the
consumption value reaches the minimum value, the printer indicates an ink end or
ink low. This value is reset when the ink cartridge is replaced.
Ink Cartridge Full
Black Ink Consumption Counter
Reset to 0
Ink Out
Ink Out Sensor CLOSED
Cartridge Flag Detects Ink Low
(Ink Out Sensor OPEN)
Consumption Counter Value: 3 x 10 7
Black Ink Consumption Counter Starts
Figure 2-23. Sensing Ink Out and Ink Low
Operating Principles
2-20 Rev. A