JPH0426393A - Carriage controller - Google Patents

Abstract

PURPOSE:To maintain a constant dot interval even if a printing operation is performed while carriage is accelerated to a required speed by a method wherein a torque which is generated immediately after a DC motor is started is controlled. CONSTITUTION:A duty signal generating part 1 which outputs a duty signal and a drive circuit 2 which drives a DC motor 3 by turning on and off in accordance with the duty signal are provided. The duty signal generating part 1 is, for instance, composed of a CPU 4 and a ROM 5 and the values of duties are stored in the ROM 5 in the order of output. The current application time data for the DC motor 3 are memorized and the current is applied to the DC motor 3 with a predetermined time interval in accordance with the current application data to control a torque which is generated immediately after the DC motor 3 is started. With this constitution, an interval between printed dots can be always maintained constant and a printing operation can be performed even while a carriage is accelerated to a required speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a carriage control device for a serial printer that prints on a recording medium by driving a carriage with a DC motor.

[Conventional technology]

FIG. 5 shows the configuration of a carriage drive device for a serial printer to which the present invention is applied.

By converting the rotational motion of the DC motor 3 into linear motion via a traction member 6 such as a timing belt and a pulley 7, a carriage 9 carrying a print head 8 is caused to travel back and forth, thereby printing on a recording medium 10 such as paper. Let's do it.

In recent years, the demand for high-speed printing has increased, and in order to achieve this, conventional methods have been to maximize the acceleration performance of the DC motor 3 by flowing the maximum @ current within the rating, and to reduce the acceleration time to a specified speed. In addition, although the printing operation is generally performed while the carriage 9 is traveling at a constant speed, some methods have been adopted, such as shortening the printing operation while the carriage 9 is accelerating from a stopped state to a constant speed. Ta.

[Problems and Objectives to be Solved by the Invention] A belt 6 is used as a typical traction member, and generally has a spring component.

In order to shorten the acceleration time, it is necessary for the DC motor 3 to generate high torque at the time of startup, but at this time, the belt 6 expands and contracts, causing vibrations in the carriage travel. When a printing operation is performed during acceleration as described above, there is a problem in that the printing dot spacing varies due to this vibration, making it impossible to obtain good printing quality.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and it is an object of the present invention to provide a carriage control device that can maintain a constant dot interval even if a printing operation is performed while the carriage is being accelerated to a predetermined speed.

[Means to solve the problem]

The carriage control device of the present invention is provided with a storage means for storing energization time data for the DC motor, and energizes the DC motor according to the energization time data at predetermined time intervals so that the DC motor is activated immediately after starting. The present invention is characterized in that it includes a torque control means for controlling the generated torque.

[Effect]

According to the above configuration, expansion and contraction of the traction member is suppressed by controlling the generated torque immediately after the DC motor is started.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing the configuration of a carriage control device for a serial printer according to the present invention.

1 is a duty signal generation unit that outputs a duty signal;
A drive circuit 2 drives the DC motor 3 by turning on and off in accordance with a duty signal.

FIG. 2 is a diagram for explaining an example of the duty signal generating section 1, which is composed of a CPU 4 and a ROM 5. As shown in FIG. R
As shown in Table 1, the duty values are stored in the OM5 in the order of output, and the CPU 4 stores the duty values in the predetermined reference period TWTDTEI as shown in FIG. 3(a).
It is programmed to output the value of duty T DUTY (n) in each section in order from Table 1.

FIG. 4 shows the configuration of the drive circuit 2. Duty T
DUTY Cn ] changes as shown in FIG. 3(a), this is applied as a control signal to the base of the transistor of the drive circuit shown in FIG. 4.

In Fig. 4, when the rotation direction is CW, the transistor Tr
By applying a control signal to the bases of transistors Tr2 and Tr4, a current flows in the direction of the solid line arrow, and when the rotation direction is CCW, a current flows in the direction of the dotted line arrow by applying a control signal to the bases of transistors Tr2 and Tr3, resulting in direct current. Motor 3 rotates.

Table 1 According to the above configuration, when the duty TDUTY(n) changes as shown in FIG. 3(a) according to Table 1 at startup, a current flows through the DC motor 3 as shown in FIG. 3(b). Since the torque generated by the DC motor 3 is expressed as the product of the torque constant and the current, the current change in (b) shows the change in the generated torque at the time of startup. In this embodiment, the duty, that is, the generated torque gradually increases during the three sections, so that it is possible to suppress expansion and contraction of the belt 6 due to sudden changes in acceleration at the time of startup.

〔Effect of the invention〕

As described above, according to the present invention, since the vibration of the carriage immediately after startup is suppressed, the printing dot interval can always be kept constant, and the printing operation can be performed even during acceleration to a predetermined speed, resulting in high-speed printing and high printing quality. A good serial dot printer can be realized.

Furthermore, since the present invention is inexpensive and can be constructed easily, the industrial effects are extremely large.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a carriage control device according to the present invention, and FIG. 2 is a diagram for explaining an embodiment of the present invention. FIG. 3 is a timing chart of the control circuit of the present invention, and FIG. 4 is a diagram for explaining one embodiment of the present invention. FIG. 5 is a schematic diagram showing the configuration of a serial printer. DESCRIPTION OF SYMBOLS 1... Duty signal generation part, 2... Drive circuit, 3
...DC motor, 4...CPU, 5...ROM,
6... Driving member, 7... Boot, 8-... Printing head, 9... Carriage, 10... Recording medium. that's all

Claims (1)

[Claims] A carriage control device having a carriage on which a print head is mounted and a DC motor for driving the carriage, the carriage control device comprising a storage means for storing energization time data for the DC motor, and storing the energization time data for the DC motor every predetermined time according to the energization time data. A carriage control device comprising: a torque control means for energizing a DC motor to control torque generated immediately after the DC motor is started.