Carriage control system for printer
AssigneeSeiko Epson Corporation
InventorsKatsuhiko Nishizawa, Yuji Takano
Life of this patent
Estimating the term…
Abstract
A carriage control system for a printer which effects printing by moving the carriage mounted on a print head to reduce the distance on either side of the printing area required for acceleration and deceleration. Various approaches to rapidly and accurately accelerating carriage to a selected constant speed and then decelerating the carriage from the constant speed to a stop are provided. Both open-loop and closed-loop control approaches are utilized.
Claims19
A carriage acceleration and constant speed control system for a printer which effects printing by moving a print head mounted on a carriage, comprising:
- a step motor for driving said carriage;
- timing means for generating a phase change instruction signal at predetermined intervals;
- encoder means coupled to the step motor for outputting a motor timing signal representative of movement of the step motor, the encoder means being synchronized with the step motor to produce a motor timing signal so that said motor can obtain the maximum rotational torque;
- interrupt means for counting a first time period from a phase change of said step motor and to selectively count a second time period from an occurrence of the motor timing signal within said first time period;
- and
- control means coupled to the step motor, timing means, encoder means and interrupt means for changing the phase of the step motor in response to the end of the second time period when the motor timing signal is output during the first time period to delay phase change to slow acceleration, whereby overshoot may be avoided.
A carriage acceleration and constant speed control system for a printer which effects printing by moving a print head mounted on a carriage, comprising:
- a step motor for driving said carriage;
- timing means for generating a phase change instruction signal at predetermined intervals;
- encoder means coupled to the step motor for outputting a motor timing signal representative of movement of the step motor, the encoder means being synchronized with the step motor to produce a motor timing signal that allows the step motor to obtain the maximum rotation torque;
- current means for applying an electric current to the step motor at one of a first level and a second level, relatively smaller that the first level;
- and
- control means for selecting each of the first and second current levels for variable time periods selected to provide a desired average driving current during each step of the step motor in response to the speed of the carriage movement to control acceleration of the step motor and selecting the first level for at least a minimum period to obtain a correction of the carriage speed.
A carriage constant speed and deceleration control system for a printer which effects printing by moving the carriage mounted on a print head, comprising:
- a step motor for driving said carriage;
- timing means for generating a phase change instruction signal predetermined based on a constant speed control pattern during constant speed control of the step motor, the encoder means being synchronized with the step motor to produce a motor timing signal that allows the step motor to obtain the maximum rotational torque;
- and
- control means for driving said step motor at constant speed during a constant speed period and decelerating said step motor to a stop during a deceleration period, said control means changing the phase of the step motor to obtain a positive torque a predetermined time after the motor timing signal when the phase change instruction signal is generated before the last motor timing signal of the constant speed period.
A carriage constant speed and deceleration control system for a printer which effects printing by moving the carriage mounted on a print head, comprising:
- a step motor for driving said carriage;
- timing means for generating a phase change instruction signal at predetermined intervals based on a constant speed control pattern during constant speed control of the step motor;
- encoder means coupled to the step motor for outputting a motor timing signal representative of movement of the step motor, the encoder means being synchronized with the step motor to produce a motor timing signal that allows the step motor to obtain the maximum rotational torque;
- and
- control means for changing the phases of the step motor at the end of the longer period between motor timing signals during the constant speed period and the period between phase change instruction signals, when the period between phase change instruction signals during constant speed control is equal to or longer than the period prior to the last motor timing signal during the constant speed period.
A carriage constant speed and deceleration control system for a printer which effects printing by moving the carriage mounted on a print head, comprising:
- a step motor for driving said carriage;
- timing means for generating a phase change instruction signal at predetermined intervals;
- encoder means coupled to the step motor for outputting a motor timing signal representative of movement of the step motor, encoder means being synchronized with the step motor to produce a motor timing signal that allows the step motor to obtain the maximum rotational torque;
- and
- control means for first changing the phase of the step motor in the reverse direction, the phase of the step motor being changed synchronous with the motor timing signal until the speed of the carriage becomes less than a predetermined speed value and then advancing the step motor forward during at least one phase change in the lower speed condition in accordance with the phase change instruction signal, whereby negative torque results which decelerates the step motor.
A constant speed and deceleration control system for a moveable element driven by a step motor comprising:
- timing means for generating a phase change instruction signal at predetermined intervals;
- encoder means coupled to the step motor for outputting a motor timing signal representative of movement of the step motor, said encoder means being synchronized with the step motor to produce a motor timing signal that allows the step motor to obtain the maximum rotational torque;
- and
- control means for changing the phase of the step motor in the reverse direction, the phase of the step motor being changed synchronous with the motor timing signal until the speed of the movable element becomes less than a predetermined speed value and then advancing the step motor forward during at least one phase change in the lower speed condition in accordance with the phase change instruction signal, whereby negative torque results which decelerates the step motor.
Dependencies are inferred from the claim text.