JPH04221658A - Drive of serial printer - Google Patents

Abstract

PURPOSE:To achieve miniaturization of a device by narrowing the running range of a printing head without reduction of a practical printing speed to a considerable extent. CONSTITUTION:If a range in which printing is possible when a drive motor for running a printing head is driven to rotate at high speed, is given as (d), first it is judged whether print data is included in the range (d) in the step 21 during printing process. If (d) is included, the motor is run at high speed in the step 22 and data is printed in the step 23. On the other hand, print data is not included in the range (d), the motor is run at low speed in the step 24 and data is printed in the step 23.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a serial printer.

0002

2. Description of the Related Art In a serial printer, a motor drives a print head to perform printing, and the printable range is the range in which the print head can be driven at a constant speed. When the print head is running, the print head is gradually accelerated to a constant speed, and when the print head is stopped, the print head is gradually decelerated so as not to step out of synchronization. Therefore, the travel range of the print head is the printable range plus the run-up range for acceleration and the braking range for deceleration.

By the way, it is desirable to narrow the travel range of the print head in order to downsize the apparatus, and one possible means for this purpose is to reduce the rotational speed of the motor.

For example, if the drive method of a 4-phase motor is changed from 2-phase excitation drive to 1-2 phase excitation drive and the rotational speed is made low, the range b for run-up and braking will change as shown in FIG. The running range L0 of the print head is narrower by 2(b-c)=2ΔL than the running range L1 of the print head during two-phase excitation driving.

[0005]

[Problems to be Solved by the Invention] However, simply reducing the rotational speed of the motor will reduce the running speed of the print head, resulting in a noticeable drop in printing speed, making it impossible to downsize the device. .

An object of the present invention is to reduce the size of the apparatus by narrowing the travel range of the print head without significantly reducing the effective printing speed.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the method for driving a serial printer of the present invention sets the printable range to d when the travel drive motor of the print head is driven at a first rotational speed. When the data to be printed is included in the range d, the motor is driven at the first rotation speed, and when the data to be printed is not included in the range d, the motor is driven at a speed lower than the first rotation speed. It is driven at a second rotational speed.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. ◆ FIG. 4 shows a schematic configuration of a drive section of a serial printer to which the drive method of the present invention is applied.

As shown in FIG. 4, the drive section of this serial printer includes a print head 1, a carriage 2 on which the print head 1 is mounted, and a carriage motor 3 for driving the carriage 2, as shown in FIG. , a paper feed device 4 for line feed, and a line feed motor 5 for driving the paper feed device 4. Further, a control device (CPU) 6 is provided as a drive control section of this printing mechanism section. The control device 6 is configured to receive print data, a signal from the paper sensor S1, and a signal from the home sensor S2. Print data is input to the control device 6 from a terminal device such as a host computer. The paper sensor S1 is a sensor that detects the presence or absence of recording paper,
The home sensor S2 is a sensor that detects whether the carriage 2 is located at the home position or not, and it is detected that there is recording paper and the carriage 2 is located at the home position when a print command is issued. At times, the printing mechanism section is operated by the control device 6 based on printing data.

The control device 6 includes a ROM (read only memory) 7, a font memory 8, a data buffer memory 9, a line buffer memory 10, a print head drive circuit 11, a carriage motor drive circuit 12, and a line feed motor drive circuit 13. are provided, and the printing mechanism section is operated through each of these circuits. ROM
7 is a storage circuit in which a control program is stored in advance. The font memory 8 is a storage circuit in which font data corresponding to character data is stored in advance. The data buffer memory 9 is a RAM (random access memory) that temporarily stores print data input to the control device 6. The line buffer memory 10 is a RAM that temporarily stores font data read into the control device 6 from the font memory 8. Print head drive circuit 1
1 is a drive circuit for driving the print head 1; a carriage motor drive circuit 12 is a drive circuit for driving the carriage motor 3; and a line feed motor drive circuit 13.
is a drive circuit for driving the line feed motor 5.

Here, when a four-phase motor is used as the carriage motor 3 and the drive system of the carriage motor 3 is set to two-phase excitation drive as shown in FIG. 3, the running range of the print head 1 is defined as L0. If the range for run-up and braking is range b, then the printable range is L0 −
2b=d. In addition, the running range of the print head 1 is set to L0.
If the drive method of the carriage motor 3 is set to 1-2 phase excitation drive within this range, and the range for run-up and braking at this time is range c, the printable range is L0 -
2c=a. When the drive method of the carriage motor 3 is set to 2-phase excitation drive and when it is set to 1-2 phase excitation drive, the rotational speed of the motor is lower in the latter than in the former. Therefore, when the drive method of the carriage motor 3 is set to 1-2 phase excitation drive, range c becomes narrower than range b when 2-phase excitation drive is used, and the printable range a in 1-2 phase excitation drive is The printable range d in the two-phase excitation drive is wider by 2(b-c)=2ΔL.

In the driving method of the present invention, as shown in FIG.
It is determined whether or not it is included in the printable range d in phase excitation drive. If included, the drive method of the carriage motor 3 is set to two-phase excitation drive in step 22, and printing is performed in step 23. On the other hand, if the print data exceeds the printable range d in two-phase excitation drive, the drive system of the carriage motor 3 is set to 1-2 phase excitation drive in step 24, and printing is performed in step 23.

The operation for printing will be specifically explained with reference to FIG. ◆When starting printing the first line, press A
Based on the position, it is determined whether the print data L1 of the first line is within the range d. In this case, since it is within the range d, two-phase excitation drive is set, and the print head runs from the left end to the right end of the first row to perform printing. When printing of this line is completed, it is determined whether the print data L2 of the second line is within the range d at position B. In this case, since it is not within the range d (the right end protrudes into the range ΔL), 1-2 phase excitation drive is set, and from the right end to the left end of the second row, the 1-2 phase excitation drive is set. The print head moves toward the target and prints. When the second line is printed, the third line is printed in the same manner as above at position C.
The print data L3 of the row is determined. In this case, since it is not within the range d (the left end protrudes into the range ΔL), 1-2 phase excitation drive is set, and from the right end of the third row to the left end The print head moves towards the area and prints. Similarly, at the D position, the print data L4 of the fourth line is determined, and in this case, since the left end extends beyond the range ΔL, 1-2 phase excitation drive is set, and the side closer to this D position, That is, printing is performed from the left end to the right end of the fourth line. Also,
At the E position, the print data L5 of the 5th line is determined, and in this case it is within the range d, so two-phase excitation drive is set and the print data L5 is determined from the side near the E position, that is, from the left end to the right end of the 5th row. Printing is performed toward the

As described above, in this embodiment, the range of the print data is determined in advance prior to the printing operation, and the two-phase excitation drive is set to the extent that the two-phase excitation drive is possible.
Only when it is out of the printable range d due to phase excitation drive, the rotation speed is lower than the rotation speed using two-phase excitation drive.
-Two-phase excitation drive is set. For this reason,
print head 1 without significantly reducing the effective print speed.
It is possible to reduce the size of the device by narrowing the travel range of the device.

[0015] Note that the present invention uses a motor drive method 1-2.
The rotational speed of the motor can be changed not only by switching between phase excitation drive and two-phase excitation drive, but also by changing the frequency at which the motor is driven. Furthermore, the traveling drive motor is not limited to a four-phase motor, and can also be applied to, for example, a single-phase motor.

Furthermore, the present invention is of course applicable not only to bidirectional printing but also to unidirectional printing.

[0017]

As described above, according to the driving method of the present invention, the range of print data is determined prior to printing, and the motor is driven at the first rotation speed or at the second rotation speed at a lower speed. Since the driving speed is selectively driven, the running range of the print head can be narrowed and the apparatus can be made more compact without significantly reducing the effective printing speed.

[Brief explanation of the drawing]

[Fig. 1] Flowchart of printing operation in the driving method of the present invention

[Figure 2] Explanatory diagram showing print data and print head movement

[
FIG. 3: Relationship diagram between print head travel distance and travel speed according to the drive method of the present invention

[Fig. 4] Main circuit block diagram of a serial printer to which the driving method of the present invention is applied.

[Figure 5] Relationship diagram between print head travel distance and travel speed

[Explanation of symbols]

d Printable range 1 when the motor is driven at the first rotation speed Print head 3 Carriage motor

Claims (1)

[Claims] [Claim 1] A first motor for driving the print head
When the printable range when driven at the rotational speed is d, if the data to be printed is included in the range d, the motor is driven at the first rotational speed, and the data to be printed is within the range d. d, the motor is driven at a second rotational speed lower than the first rotational speed.