JPS5931473B2 - paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feed device such as a line printer, and more specifically to a line feed control method for a paper feed device.

Even in the worst case of paper feeding, where only the line feed operation is repeated continuously without printing, the paper feed motor is not burnt out and the motor drive circuit is not damaged due to heat. It is prohibited to start changing operations.

Since the setting of the line feed prohibition time is designed considering the above-mentioned worst case, the effective printing speed is limited in normal usage conditions that involve printing operations. An object of the present invention is to improve the effective printing speed by shortening the line feed prohibition time during normal work involving printing operations in which the paper feed motor and drive circuit are not overheated.

For this reason, the present invention provides two or more types of line break prohibition times,
When the temperature rise of the paper feed motor or drive circuit is small, the shorter line feed prohibition time is selected to improve the effective printing speed. The heat generated by the motor is due to the ohmic heat consumed by the windings. Therefore, whether or not the motor is overheated can be determined by detecting the temperature of the motor windings. However, installing a temperature detection element inside the motor takes up a lot of space. Therefore, the present invention estimates the temperature of the motor windings based on the temperature of a resistor with a small resistance value inserted in series in the motor circuit or the heat radiation fin of the motor drive circuit, and the temperature of the resistor or heat radiation fin is set to a predetermined value. When this is reached, the line break prohibition time is lengthened to suppress the rise in temperature of the motor and drive circuit, but of course the temperature of the motor windings may also be directly detected. FIG. 1 is a block diagram showing one embodiment of the apparatus of the present invention, in which 1 is a printing paper, 2 is a tractor that engages with feed holes provided on both sides of the printing paper 1 to feed the printing paper 1, and 4 is a paper feeder. The output shaft of the motor is connected to the drive shaft of the tractor 2 via a coupling 3. Reference numeral 5 denotes an encoder disk mounted on the shaft of the motor 4, 6 an encoder sensor consisting of a light emitting element and a light receiving element provided facing each other via the encoder disk 5, and 7.
8 is the control circuit, and 8 is the output signal of the control circuit 7.
This is a drive circuit consisting of a servo amplifier that amplifies the current to a level that can be driven.

A resistor 9 is inserted between the motor 4 and the drive circuit 8 and is preferably a resistor sealed in a metal case, such as a metal clad resistor.

Reference numeral 10 is a temperature sensor that detects the temperature of the resistor 9 and generates an output when the temperature reaches a predetermined value, and is preferably a thermal switch using a heat-sensitive ferrite or a thermostat using a bimetal.

When the temperature of the resistor 9 reaches a predetermined value, the control circuit 7 is activated by the output of the temperature sensor 10 to lengthen the line feed prohibition time and suppress the temperature rise of the motor 4 and the amplifier of the 1 drive circuit 8. FIG. 2 shows a one-wheel circuit in the control circuit 7 for this purpose, where 11 is an inverter, 12 and 13 are triggerable monomultis, and the output pulse width T of the monomulti 12 is the output of the monomulti 13. The pulse width is set smaller than the pulse width T2.

14 to 16 are NAND gates, and 17 is an AND gate.

While the temperature sensor 10 is not generating an output, the NAND gate 15 closes its gate and the NAND gate 14 opens its gate, so that the line feed prohibition time is short or equal to the pulse width T1 of the triggerable monomulti 12. However, the temperature of the resistor 9, that is, the motor winding, reaches a predetermined value and the temperature sensor 1
When 0 generates an output, the NAND gate 15 opens the gate, so the line break prohibition time is long and becomes the pulse width T2 of the triggerable monomulti 13.

The above explanation will become clearer by referring to the time chart in FIG. That is, when the motor 4 is not overheated, a short line feed prohibition time T is set to improve the effective printing speed, and when the motor 4 is overheated, a long line feed prohibition time T2 is set to improve the motor 4, drive circuit, etc. This is designed to prevent thermal damage to the material. As described above, according to the present invention, it is possible to improve the effective printing speed and to prevent thermal damage to the motor, drive circuit, etc.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the device of the present invention;
The figure is a block diagram showing a single wheel circuit constituting the present invention, and FIG. 3 is a time chart illustrating the present invention.

Claims (1)

[Claims] 1 A tractor driven by a motor to feed paper, and a predetermined first timer set by a first timer from the end of paper feeding.
A second time limit means for setting a second line feed prohibition time shorter than the first line feed prohibition time of the first time limit means, the paper feeding device configured to prohibit the start of the next paper feed until a line feed prohibition time has elapsed. and temperature detection means for detecting the temperature of the motor and generating an output when a predetermined value is detected, a second line feed prohibition time is set until the temperature detection means generates the output, and the temperature detection means outputs the output. A paper feeding device characterized in that a first line break prohibition time is set after a line break occurs.