Print wheel and carriage drive system for a printer
First Claim
Patent Images
1. A serial printer comprising:
- a motor;
a first counter for storing a rotational position of said motor;
a latch for storing a destination position of said motor;
a first operation unit for receiving outputs from said latch and said first counter and for calculating an amount of position error therefrom;
a first conversion table containing target values corresponding to amounts of position error for receiving an output from said first operation unit;
a pulse generator responsive to a rotation of said motor for generating pulse signals;
a second counter for counting reference pulses generated in an oscillator during one cycle of the pulse signals generated from said pulse generator;
a second conversion table containing a plurality of numeric values associated with average velocities delayed by one cycle of the pulse signals for receiving an output from said second counter;
a second operation unit for receiving target values corresponding to amounts of position error from said first conversion table and numeric values associated with average velocities delayed by one cycle of the pulse signal from said second conversion table and for calculating an error signal from said target values and said numeric values;
a D/A converter for converting an output of said second operation unit into an analog signal;
an analog circuit for generating a signal by combining an analog signal generated during a predetermined period in response to the rotation of said motor and a phase-advanced compensation signal; and
a selection switch for temporarily connecting said motor to said analog circuit when said motor reaches a stopping region, said motor otherwise being connected to said D/A converter.
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Abstract
Disclosed is a printer which drives a drive motor for a type wheel or a carriage therefor by a signal derived by processing a first digital signal resulting from a position error signal and a second digital signal which is delayed by a predetermined time period. The digital signals can be processed by an LSI chip which assures a highly reliable, low cost and compact printer.
38 Citations
28 Claims
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1. A serial printer comprising:
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a motor; a first counter for storing a rotational position of said motor; a latch for storing a destination position of said motor; a first operation unit for receiving outputs from said latch and said first counter and for calculating an amount of position error therefrom; a first conversion table containing target values corresponding to amounts of position error for receiving an output from said first operation unit; a pulse generator responsive to a rotation of said motor for generating pulse signals; a second counter for counting reference pulses generated in an oscillator during one cycle of the pulse signals generated from said pulse generator; a second conversion table containing a plurality of numeric values associated with average velocities delayed by one cycle of the pulse signals for receiving an output from said second counter; a second operation unit for receiving target values corresponding to amounts of position error from said first conversion table and numeric values associated with average velocities delayed by one cycle of the pulse signal from said second conversion table and for calculating an error signal from said target values and said numeric values; a D/A converter for converting an output of said second operation unit into an analog signal; an analog circuit for generating a signal by combining an analog signal generated during a predetermined period in response to the rotation of said motor and a phase-advanced compensation signal; and a selection switch for temporarily connecting said motor to said analog circuit when said motor reaches a stopping region, said motor otherwise being connected to said D/A converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device for moving a movable member to a destination position, comprising:
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transducer means for producing a transducer signal dependent upon movement of said member; means responsive to a transducer signal from said transducer means for producing a digital position signal representative of the current position of said member; means for producing a digital target position signal representative of the destination position of said member; means responsive to the digital position signal and the digital target position signal for producing a digital position error signal representative of the position difference between the current position and the destination position of said member; first conversion table means responsive to the digital position error signal for producing a digital target speed signal representative of a desired target speed for driving said member; means responsive to the transducer signal produced by said transducer means for generating a digital speed signal representative of the actual speed of said member; means responsive to the digital speed signal and the digital target speed signal for producing a digital speed error signal representative of the speed difference between the actual speed and the desired target speed for said member; means responsive to the digital speed error signal for developing a first drive signal to drive said member toward the destination position; means responsive to the transducer signal produced by said transducer means for deriving therefrom a second drive signal; means for driving said member in accordance with either one of the first and second drive signals; and means for selectively applying one of the first and second drive signals to said driving means so as to drive said member up to the vicinity of the destination position in accordance with the first drive signal and in the vicinity of the destination position in accordance with the second drive signal to rest at the destination position. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A device for moving a movable member to a selected one of a plurality of discrete positions, comprising:
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means for producing a digital position signal representative of the discrete position of said movable member; means for producing a digital target signal representative of a selected one of said plurality of discrete positions; means responsive to said digital position signal and said signal target signal for producing a digital position error signal; means responsive to said digital position error signal for deriving therefrom a first drive signal which is available to drive said movable member toward said selected discrete position; transducer means for producing transducer signals representative of the movement of said movable member with respect to respective discrete positions; means responsive to said transducer signals for deriving therefrom a second drive signal which is available to bring said movable member to rest, said second drive signal being generated when said movable member resides in the vicinity of said selected discrete position, the second drive signal being an analog signal synthesized by combining the transducer signals with a phase-advanced transducer signal; and drive means for driving said movable member toward said selected discrete position under control of said first drive signal and for bringing said movable member to rest at said selected discrete position under control of said second drive signal. - View Dependent Claims (26, 27, 28)
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Specification