Abstract: In a control apparatus for a pulse motor, both a smooth acceleration property and a stable constant speed operation characteristic are realized in a process wherein the motor starts to run and then is accelerated to enter a constant speed operating state. A target value for the rotor phase, and motor speeds at N different phase switching times during an acceleration period of the pulse motor are determined in advance. Then, phase control values (for conducting respective phase switchings when the rotor phase reaches the target phase of each phase switching) and speed control values (for conducting respective phase switchings so that the motor speed at each phase switching further approaches a target speed) are integrated with each other in accordance with a predetermined weighting function, and then executed. In an early stage of acceleration, the weight of the phase control predominates. As the motor speed increases, the speed control is weighted more and more heavily relative to the phase control.

Abstract: An impact dot printer designed to reduce noise, including a first cover, a second cover, and an overlap portion therebetween. The first cover is located above a print section, and may include sound wave reflecting plates, sheet guide plates, and a sound absorbing member, each reflecting plate, each sheet guide plate, and the sound absorbing member being arranged close to the print section. The second cover is rotatable relative to the first cover and forms a printed sheet discharge path together with the first cover. The second cover also has sound wave reflecting plates and sheet guide plates. Each sheet guide plate is designed to be projected farther from the associated cover than the corresponding reflecting plate on said cover. The distance between adjacent sheet guide plates is made smaller than the width of the smallest sheet to be used in the printer.

Abstract: An impact dot printer designed to reduce noise, including a first cover, a second cover, and an overlap portion therebetween. The first cover is located above a print section, and may include sound wave reflecting plates, sheet guide plates, and a sound absorbing member, each reflecting plate, each sheet guide plate, and the sound absorbing member being arranged close to the print section. The second cover is rotatable relative to the first cover and forms a printed sheet discharge path together with the first cover. The second cover also has sound wave reflecting plates and sheet guide plates. Each sheet guide plate is designed to be projected farther from the associated cover than the corresponding reflecting plate on said cover. The distance between adjacent sheet guide plates is made smaller than the width of the smallest sheet to be used in the printer.

Abstract: In a serial impact printer, a printing head having an impact wire pin array of two arrangement lines is mounted on a carriage in such a way that the pin arrangement lines are inclined by an angle .theta. with respect to the virtual vertical direction. The respective wire pins in the array are driven at timings different delay time by delay time according to the inclination angle .theta.. The control circuit for determining the drive timings comprises a circuit for turning on the respective wire pins at the delay time intervals and a circuit for turning off the respective wire pins in sequence at the delay time intervals after a predetermined time has elapsed. It is desirable that the inclination angle .theta. satisfies the following formula:tan .theta..ltoreq.a/(2.multidot.b)where 2a denotes the pitch between two adjacent wire pins arranged along a single arrangement line of the array, and b denotes a distance between the two arrangement lines of the array.

Abstract: The disclosed invention achieves a proper speed control of a sheet feeding motor for a serial printer that uses an astable power supply with a simple operation irrespective of variations in power supply voltage. The invention provides a method of and an apparatus for controlling the frequency of a sheet feeding pulse motor for a printer in accordance with the power supply voltage during sheet feeding.