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US 5,415,480 AGranted
Printer having a stepping motor for driving and retaining a type wheel
AssigneeCanon Kabushiki Kaisha
InventorNoriyuki Kikugawa
Life of this patent
Estimating the term…
Abstract
In a printer which selects a character by moving a type wheel by a stepping motor, phases other than a stable phase of windings of the stepping motor are shorted when a rotor of the stepping motor comes to a vicinity of a stable point of a target phase, and an exciting time of the stable phase is gradually extended. The primary drive signal is turned off during energization of a retaining signal and during hammer energization.
Claims8
A printer comprising:
- input means for inputting a character to be printed;
- a stepping motor having a plurality of coils and which may be energized in a plurality of phases each corresponding to one said coil for driving a type wheel including a plurality of type elements to position any one of the type elements at a target position for printing, each of the phases being respectively allotted to one of the type elements of the type wheel;
- arithmetic operation means for calculating the target position based on the character to be printed to drive said stepping motor;
- means responsive to selection of a type element by said arithmetic operation means for producing a primary drive signal to sequentially energize the phases of said motor until the phase allotted to the selected type element is energized;
- energizing means for applying a retaining signal to the phase allotted to the selected type element, the signal having a signal form that increases gradually in comparison to the primary drive signal;
- and
- means for applying a counter electromotive force to the adjacent phases of the allotted phase of said stepping motor during the time period encompassing the energization of the allotted phase of said primary drive signal, the turning off of the primary drive signal when the selected type element reaches the vicinity of the target position, and the time period encompassing the energizing of the retaining signal.
4 more elements
A stepping motor and damping apparatus for driving and positioning a member, said apparatus comprising:
- a stepping motor which may be energized in a plurality of phases for driving the member;
- means connected to said stepping motor for producing, based on a profile stored in a memory, a primary drive signal for sequentially energizing said phases of said motor until a predetermined phase is energized;
- means, connected to said stepping motor, for applying a retaining signal to said predetermined phase to retain the stepping motor at a target position, the retaining signal being a gradually increasing signal;
- and
- means connected to said stepping motor and said producing means for applying a counter electromotive force to an adjacent phase of the stepping motor during the time period encompassing the energizing of said phases of said motor by said primary drive signal, during turning off of the primary drive signal after the predetermined phase has been energized, and during the time period encompassing the applying of the retaining signal to the predetermined phase, to damp the stepping motor.
2 more elements
A printer comprising:
- a type wheel provided with a plurality of types elements;
- a hammer adapted to hit a type element of the type wheel;
- a stepping motor having a plurality of driving phases for rotating said type wheel;
- first control means, coupled to said stepping motor, for supplying a first, main driving signal to said stepping motor to sequentially drive a predetermined phase of said stepping motor;
- second control means, coupled to said stepping motor, for damping said stepping motor according to turning off of the main driving signal of the predetermined phase;
- counter electromotive force controlling means for supplying a counter electromotive force to a phase different from the predetermined phase during the time period the first, main driving signal is supplied by said first control means and during the time the second control means turns off the main driving signal;
- means, coupled to said stepping motor, for supplying a second driving signal to said stepping motor, the width of which is gradually changed after reducing an overdamping of said stepping motor;
- and
- third control means for driving said hammer to hit a type element of said type wheel after supplying the second driving signal to said stepping motor,
- wherein said counter electromotive force controlling means supplies the counter electromotive force to a phase different from the predetermined phase during the time period encompassing the supplying of the second driving signal to said stepping motor.
7 more elements
A printer comprising:
- a type wheel provided with a plurality of types elements;
- a hammer adapted to hit a type element of the type wheel;
- a stepping motor having a plurality of driving phases for rotating said type wheel;
- first control means, coupled to said stepping motor, for supplying a first, main driving signal to said stepping motor to sequentially drive a predetermined phase of said stepping motor;
- second control means, coupled to said stepping motor, for damping said stepping motor according to turning off of the main driving signal of the predetermined phase;
- counter electromotive force controlling means for supplying a counter electromotive force to a phase different from the predetermined phase during the time period the first, main driving signal is supplied by said first control means and during the time the second control means turns off the main driving signal;
- means, coupled to said stepping motor, for supplying a second driving signal to said stepping motor, the width of which is gradually changed after reducing an overdamping of said stepping motor;
- and
- third control means for driving said hammer to hit a type element of said type wheel after supplying the second driving signal to said stepping motor,
- wherein said counter electromotive force controlling means supplies the counter electromotive force to a phase different from the predetermined phase during the time period encompassing the supplying of the second driving signal to said stepping motor, and during the driving of the hammer by said third control means.
7 more elements
Dependencies are inferred from the claim text.