Paper Feed Motor Drive Circuit - Epson SQ-1170 Service Manual

REV.-A

2.3.4 Paper Feed Motor Drive Circuit

A stepping motor is used in the paper feed motor drive circuit of this printer.
The motor is driven by 2-2 phase excitation and constant-current arrangement. For a single pulse, paper
is fed 1/360 inch (minimum value). The acceleration/deceleration control is not applied to the paper
feed rate less than 3 steps.
The feeding speed is varied depending on the type of paper, etc.
The constant-current drive circuit is made by STK67 126, which detects the current flowing in the coil
of the stepping ~otor, and keeps the current constant by cutting the current that exceeds a certain
value. This value can be set at user's option through the external circuit. The value set by the external
circuit is inputted through the port on E05A65 and outputted to STK67 126 in 4 steps. (The motor
retaining mode is also included.)
The phase of the paper feed motor is also switched through E05A65.
CPU
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Figure 2-41. Paper Feed Motor Drive Circuit
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IN/~ A
IN/6 B
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