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US 4,971,466 AGranted
Printing apparatus having a rotatable member rotatable in incremental steps smaller than the pitch of a detent gear and including means for accurately retaining the rotatable member at a predetermined position when the detent mechanism is inoperable
AssigneeCanon Kabushiki Kaisha
InventorHiroatsu Kondo
Life of this patent
Estimating the term…
Abstract
There is described a printing apparatus in which line feed is achieved by rotating a platen with a paper advancing motor and the printing is conducted while the platen is stopped by the paper advancing motor. The printer is further provided with a detent mechanism for stopping the platen at the interval of a determined angle, and a solenoid for deactivating the function of the detent mechanism.
Claims15
A printing apparatus for recording on a recording medium, comprising:
- a rotatable member for feeding a recording medium;
- a motor for driving said rotatable member;
- drive transmission means for transmitting the drive force of said motor to said rotatable member to rotate said rotatable member;
- detent means adapted to assume a restraint state in which rotation of said rotatable member is restrained and a release state in which said restraint state is released thereby permitting rotation of said rotatable member;
- drive means for placing said detent means into the release state, in response to a predetermined signal;
- control means for controlling said detent means and said motor to electrically lock said rotatable member by reducing the voltage applied to said motor to a retaining voltage after said rotatable member is rotated by a predetermined amount by applying a drive voltage to said motor while maintaining said detent means in the release state.
3 more elements
Printing apparatus comprising:
- a rotatable member for feeding a printing medium;
- a detent gear of a predetermined gear pitch mounted for rotation with said rotatable member;
- lever means mounted for engaging said detent gear to specify rotation positions of said rotatable member;
- means for locking and releasing the engagement of said lever means to and from said detent gear;
- a stepping motor, which rotates step by step in response to a rotation signal, for rotating said rotatable member, a rotary step of said rotatable member caused by one rotary step of said stepping motor being smaller than the predetermined gear pitch of said detent gear;
- and
- means for controlling said locking and releasing means to release the engagement of said lever means from said detent gear when the rotatable member is rotated by the stepping motor, and to engage the lever means with the detent gear to lock said rotatable member after said rotatable member is rotated by said stepping motor by an amount which corresponds to a multiple of the predetermined gear pitch of said detent gear and is then stopped, and for controlling said locking and releasing means to maintain said lever means released from said detent gear after said rotatable member is rotated by said stepping motor by an amount which does not correspond to a multiple of the predetermined gear pitch of said detent gear and is then stopped so that said lever means does not normally engage said detent gear, wherein said rotational position of said stepping motor is retained in response to a retention signal.
4 more elements
Dependencies are inferred from the claim text.