Epson SEIJ98006 manual EPSON Stylus Color, Revision C, Encoder, Operating Principles

EPSON Stylus Color 900 Revision C

￿Encoder:

This sensor increases accuracy of ink ejection timing. Irregular movement of the carriage, usually caused by a paper jam, can be also detected based on the change in input signals of this sensor. Carriage movement is monitored by running the encoder belt (with lines printed on it with increments of 180 dpi) between the photo sensor attached to the carriage. Also, if the printer receiveds a large impact during printing, the input signal cat not be properly read, and in some cases print quality decreases with a dot missing problem. This is because this printer forms one dot by producing trapezoidal head driving waveforms based on the cycle determined by the

￿signals sent from the encoder.

Ink cartridge sensor:

If the printhead drives without any ink cartridge installed (= false firing), it damages the printhead unit. Also, compared with other printers, this printer uses the largest number of PZT and accordingly releases more heat. For this reason, the ink itself inside the cartridge serves to lower the temperature inside the cartridge, and black and color ink cartridges can be separately detected to avoid false firing.

Detection process: An ink cartridge is detected when the ink cartridge being installed activates the actuators, which then pushes

￿the micro switch.

CR home position sensor:

When the printer is turned on, the CRHP sensor confirms the CR is in the home position during the home position seeking sequence. Then the printer can determine the CR control afterwards. The printing column position is also confirmed based on the signals from the sensor.

Detection process: The carriage is detected when the flag interrupts the light beam in the photo sensor which is located on the right end of the printer mechanism.

￿PE (Paper End) sensor:

The PE sensor detects the following conditions:

Whether or not paper is set at power on.

Whether or not paper is properly fed from the ASF with the

￿paper feed command.

Whether or not the printer properly ejects a page of printed paper after rotating the PF (Paper Feed) motor with the predefined distance.

Detection method: A photo sensor is used to detect the actuator’s motion; the actuator is pushed/released by the

￿leading/rear edge of the paper.

ASF sensor:

Various parts in the ASF are engaged in the phase that is designed to feed paper at the approariate timing. If the timing is wrong, mis- match occurs between paper feeding by the ASF and paper transportation for printing, and non-feeding or paper jam will occur. Therefore, this printer monitors the sensor condition at power on and before and after paper is fed/ejected according to the pump/

￿ASF motor’s roational distance.

Power on/off detection:

Unlike primary-side switch type products, ASIC E05B60 (IC3) on the C265 main board is used to monitor the power on/off operation instead of any sensor. When the power switch on the control panel is turned off, the change from 5 V to ground level is detected at the Pin 33 of the IC3, and the program starts the power off sequence with this change. Power used during the sequence is supplied by the electrolysis condenser C84 in the voltage drop delay circuit in the secondary side of the C265 PSB/PSE board. The electrolysis condenser continues to supply power until all electric charge inside is completely discharged.

Operating Principles Electrical Circuit Operation Principles 66