Reset Circuits; Sensor Circuits - Epson STYLUS COLOR 3000 Service Manual

Reset Circuits

The C203 main board contains two reset circuits: one for the logic line (+5 V) and one for the power line
(+42 V). Reset IC M51955BFP (IC3) monitors the +42 V line. When the voltage level drops below +33.2 V, It
outputs /NMI signals to the CPU and the gate array to cut off the power line for the motors. Reset IC
RST592D (IC9) monitors the +5 V line. When the voltage level drops below +4.2 V, it sends a low pulse.
While the printer power is on, it outputs LOW until a stabilized +5 V is produced to ensure the CPU's proper
operation.
+42V

Sensor Circuits

The CPU and gate array E05B45 (IC 16) monitor the printer condition by referring to the signals from the 13
sensors described below.
HP: Output from the HP (Home Position) sensor.
The HP sensor for this printer uses a reliable photo interrupter system. The HP signal is LOW when the CR
unit is at the home position and HIGH when it is not at the home position.
PE_R: Output from the rear PE (Paper End) sensor.
The rear PE sensor, attached to the rear part of the paper path, detects the presence of continuous paper or
cut sheets in the rear paper slot. A mechanical switch is used for this sensor; the PE_R signal is HIGH when
paper is detected and LOW when paper is not detected.
PE_F: Output from the front PE (Paper End) sensor.
The front PE sensor, located in the paper guide unit, detects paper in the ASF. This sensor uses a
mechanical switch; the PE_F signal is HIGH when paper is detected and LOW when paper is not detected.
REL: Output from the release sensor.
The release sensor is built into the rear part of the left frame of the printer mechanism. It determines whether
the release lever is set to cut sheet (friction mode) or to continuous paper (tractor mode). The REL signal is
LOW when the lever is set to friction mode and HIGH when the lever is set to tractor mode.
CO_B/C/M/Y: Output from each ink cartridge sensor.
The ink cartridge sensors are attached to each ink cartridge holder in the printer mechanism. They determine
whether the corresponding ink cartridges are installed. A mechanical switch is used for this sensor; the
CO_B/C/M/Y signal is LOW when the cartridge is installed and HIGH when the cartridge is not installed.
When the sensor detects that there is no cartridge, the ink consumption counter is reset.
IE_B/C/M/Y: Output from each ink end sensor.
The ink end sensors, attached to each ink cartridge holder in the printer mechanism, use a mechanical
switch system and a LOW or HIGH IE_B/C/M/Y signal, to detect when the ink is out. The ink end sensor
detects that ink is out when the ink reservoir drops to 5 % of capacity. If no ink is detected and an ink
cartridge is detected by the ink cartridge sensor, the ink consumption counter is reset.
EPSON Stylus Color 3000 Service Manual
M51955BFP
(IC3)
NC5
CPU
H8S/2655
NMI
OUT
(IC5)
Figure 2-16. Reset Circuit Block Diagram
+5V
RST592D
(IC9)
VOUT RESET
RESET
RESET
EPSON Stylus COLOR 3000
GA
E05B45
(IC16)
GA
E05B33
(IC6)
2-17