5. CIRCUIT DESCRIPTION
5.1 PWA Block Diagram
STP cover open switch
STP AC adapter
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| 5V | 1 |
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J1 | 2 |
| regulator |
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| PAPER_SENS |
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| STPL_H/P | 2 |
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| HOOK_SW | 5V | 3 |
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| Motor | Motor drive | CW | 6 |
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| circuit | CCW | 7 |
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| controll |
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| circuit | Motor drive |
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STP LED PWA
STP paper set sensor
STP sensor PWA
STP
5.2 Functional Description
The STP operates the stapler through the STP controller PWA. When the power of the copier is turned on, a power supply is also delivered to the STP to enable stapling. When paper is loaded into the stapler, the STP paper set sensor detects the presence of paper (changing from “High” to “Low”), and 200 ms later the CW signal turns ON (changing from “Low” to “High”) to operate the STP motor forward. When the motor operates, the gears and cams of the stapler operate for stapling. When the STP home position sensor detects the home position of the stapler (changing from “High” to “Low”) after the CW signal is activated, the CW signal turns OFF.
If the STP home position sensor remains at “High” level (a failure to return to the home position) for some reason even if a fixed time (approx. 900 ms) has elapsed after the CW signal turns ON, the CW signal turns OFF and 100 ms later the CCW signal is turned ON (changing from “Low” to “High”) to operate the STP motor reversely. In practice, however, if the STP has locked up mechanically, an overload occurs so that the fuse installed on the STP CONT PWA will blow or the protective circuit of the AC adapter will function to cut the delivery of the power supply (shutdown).
If the stapler is not at the home position when the power is turned on (“High” level), about 60 ms later the CCW signal is turned ON (changing from “Low” to “High”) to operate the motor reversely allowing the stapler to return to the home position.
October 2000 © TOSHIBA TEC | 5 - 1 |
