JPH07115496B2 - Dot tomato printer type print control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a print control device for a dot matrix printer suitable for an information processing device such as a handheld computer having a small power supply capacity.

(Prior Art) A dot matrix printer is a device that mounts a dot generation mechanism on a carriage that moves in the width direction of the printing paper and that drives the dot generation mechanism in synchronization with the movement of the carriage to print characters and patterns. A step motor is used for transporting the carriage in order to match the position of the dot generation mechanism with the drive timing of the dot generation mechanism.

According to this, the drive and transfer of the dot generation mechanism can be synchronized by the timing signal source, but on the other hand, a power supply device capable of supplying a high peak power at the time of driving the step motor is required. In the device, there was a problem that the battery was exhausted.

(Object) In view of the above problems, an object of the present invention is to provide a control device for a dot-matrix printer that can reduce power consumption at peak time as much as possible.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

FIG. 2 shows a dot-matrix type printer to which the present invention is applied, in which reference numeral 6 is a DC motor mounted on a base 14, which is connected to a timing belt 16 via a gear train 15. . Reference numeral 17 denotes a carriage on which the dot generation mechanism 1 and the ink ribbon cartridge 18 are mounted, and the guide rod 1
It is configured to be guided by 9, 19 and reciprocate in the axial direction of the platen 20 by the timing belt 16.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 is the above-mentioned dot generating mechanism mounted on a carriage. In this embodiment, a plurality of heater elements 1a, 1a are provided.
It is composed of a thermal head in which are arranged in a vertical relationship. One terminal of each of the heat generating elements 1a, 1a, ... constituting the thermal head is commonly connected, and the other terminal of each heat generating element is connected to the drive circuit 5 driven by the pattern signal from the CPU4. is doing. The drive circuit 5 is connected to a power source 9 via a switching transistor 3 which is turned on and off by an output from a conduction time control circuit 2 described later. 6 is a DC motor that moves the carriage in the width direction of the printing paper.
A speed generator 7 for detecting the rotation phase of the motor is connected to one end of the rotary shaft. The power supply terminal of the DC motor 6 is connected to the power supply 9 via the switching transistor 8. 10 is a time measuring device including a counter,
The time is set by the CPU4, and clocking starts in synchronization with the signal from the speed generator 7, and when the set time is reached
It is configured to output a LOW level signal. 11
Is an AND gate, the motor drive signal from the CPU 4 is input to one input terminal, the signal from the clock device 10 is input to the other input terminal, and the output terminal is a switching transistor 8 for controlling the DC motor 6. It is connected to the base.

Reference numeral 2 denotes the aforementioned energization time control circuit, which receives the signal from the speed generator 7 and the signal from the power supply voltage detection circuit 12, and synchronizes with the signal from the speed generator 7 to approximately square the voltage of the power supply 9. It is configured to output a pulse signal having an inversely proportional width. Reference numeral 13 in the figure denotes a gain adjusting circuit for adjusting the signal amplitude from the speed generator 7 to a constant level.

Next, the operation of the apparatus configured as described above will be described based on the waveform diagram shown in FIG.

When the normal mode print data, that is, the print data for printing the font shown in FIG. 4I, is output from the host device (not shown), the CPU 4 sets one cycle of the signal from the speed generator 7 to 1 cycle. This is adopted as the printing timing, and at the same time, the pause time Tf is selected for the motor drive signal and set in the clock device 10. When such a preliminary operation is completed, a DC motor drive signal is output from the CPU 4, the switching transistor 8 is turned on via the AND gate 11, and drive power is supplied from the power supply 9 to the DC motor 6. As a result, the DC motor 6 starts rotating to start moving the dot generating mechanism 1 in the paper width direction.

By rotating the DC motor 6, the speed generator 7 outputs a sine wave signal corresponding to the rotation angle of the DC motor 6. When the sine wave signal reaches a preset phase, for example, a zero crossing point, the timer device 10 starts operating and outputs a LOW signal. Upon receipt of this LOW signal, the motor control switching transistor 8 is turned off and the power supply to the DC motor 8 is stopped. By stopping the energization, the DC motor 8 further moves the dot generating mechanism 1 while reducing the speed.
On the other hand, the energization time control circuit 2 outputs a pulse having a width almost inversely proportional to the square of the power supply voltage when the speed signal reaches a preset phase, turning on the switching transistor 3 to turn on the drive circuit 5 To the operating state. As a result, the heat generating elements 1a, 1a, ... Corresponding to the print data input from the host device are energized for a period of time that is substantially inversely proportional to the square of the power supply voltage, and are supplied with a constant heating power to maintain a constant density. Print dots on paper. When the time Tf set in the timing device 10 has elapsed, the timing device 10 outputs a Hi level signal to turn on the switching transistor 8 to supply drive power to the DC motor 6 again to increase the rotation speed of the motor 6. . After that, power is supplied to the DC motor 6 until the time corresponding to two cycles of the signal from the speed generator 7 elapses in this manner. When the signal from the speed generator 7 has passed two cycles, the timing device 10 outputs a LOW level signal and repeats the above process again.

After that, one printing timing is formed by two cycles of the signal from the speed generator 7 in this manner, and the power consumption, that is, the current is averaged by alternately energizing the motor 6 and dot generation within one printing timing. While printing the dot pattern corresponding to the print data.

By the way, the condensation mode print command from the host device,
That is, when a command for printing a font compressed in the row direction as shown in FIG. 4 II is output, the CPU 4 causes the speed generator 7
One cycle of the sine wave signal from is used for one printing timing, and at the same time, the pause time Tf 'is selected for the motor drive signal and set in the timer device 10. When the DC motor 6 starts to rotate in such a state, the speed generator 7 outputs a signal corresponding to the rotation phase of the DC motor 6. When the signal reaches the preset phase, the timer device 10 starts operating and outputs a LOW level signal to stop energizing the DC motor 6. By stopping this energization, the DC motor 6 transfers the dot generating mechanism 1 at a reduced speed. On the other hand,
When the speed signal reaches a preset phase, the energization control circuit 2 outputs a pulse having a width substantially inversely proportional to the square of the power supply voltage to turn on the switching transistor 3 to activate the drive circuit 5. , Print a predetermined dot with the thermal head.

In the condensation mode, since one cycle of the signal from the speed generator 7 is set to one printing timing, the dot generation mechanism 1 is driven at a half time interval of the normal mode, so that the characters to be printed are , The pattern is compressed in line length, that is, the character width is halved.

FIG. 5 shows a second embodiment of the present invention,
In the figure, reference numeral 21 is a photo encoder attached to the end of the DC motor 6 for moving the carriage, and a code plate 22 provided with detection marks 22a, 22a at equal intervals is fixed to one end of the rotation shaft of the motor 6. , The light emitting element 23 facing the code plate 22.
And a light receiving element 24 are arranged. According to this embodiment, the rotation phase of the DC motor can be taken out as a digital signal (Fig. 6), and the signal processing circuit can be simplified.

(Effect) As described above, according to the present invention, the carriage equipped with the dot generation mechanism is moved by the DC motor, so that the drive timing of the dot generation mechanism and the drive timing of the motor are within one printing cycle. The drive power can be averaged by being dispersed. In addition, since the speed signal of the DC motor is used as the reference timing signal, not only the servo control mechanism can be dispensed with, but the cost of the carriage moving mechanism can be reduced, and the overshoot that tends to occur in servo control can be avoided. The dot generation mechanism can be moved smoothly.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention,
2 is a perspective view showing an embodiment of a dot matrix type printer to which the control device of the present invention is applied, FIG. 3 is a waveform diagram showing the operation of the same device, and FIG. 4 is a print pattern by the same device. FIG. 5 is a perspective view showing another embodiment of the present invention, and FIG. 6 is a waveform diagram showing the operation of the control device by the device shown in FIG. 1 ... Dot generation mechanism 3 ... Switching transistor 6 ... DC motor, 7 ... Speed generator 21 ... Photo encoder 17 ... Carriage

Claims (1)

[Claims] 1. A print control device for a dot matrix type printer, in which a carriage equipped with a dot generation mechanism is moved by a DC motor for recording, and a rotational phase detection means for outputting a periodic signal in synchronization with the movement of the carriage, Printing control of a dot matrix printer characterized by comprising means for generating a signal for alternately driving the dot generating mechanism and the DC motor within a fixed period of the periodic signal from the rotational phase detecting means. apparatus.