JPS587385A - Scanning mechanism for printer - Google Patents

Abstract

PURPOSE:To provide the titled mechanism capable of bringing a carriage into a steady travelling condition speedily and within a short distance of tavelling, by applying an overdriving force to a motor with a predetermined timing at the rising-up time of the travelling of the carrige. CONSTITUTION:A signal a is generated by a timing-generating circuit 30 at an undershoot part B1 of a wave form of vibration, and a transistor 25 is made to conduct by the signal a. A voltage V1 higher than a normal voltage V2 is impressed on a stepping motor coil, and an overdriving force such as to prevent the carriage velocity from decreasing is applied to the motor. The rising-up characteristic of travelling of the carriage is changed as indicated by the solid line in the figure, and the steady velocity is attained rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the scanning mechanism of a printer, and in particular, to effectively apply a braking force to the carriage when the carriage starts running, thereby shortening the carriage. time,
This allows the vehicle to be in steady running condition within a short distance.

In printer scanning, when the carriage starts running,
It is preferable to keep the carriage in steady state for a short period of time and within a short distance, so that it is necessary to rapidly accelerate the carriage. However, when a sudden acceleration force is applied to the carriage, the carriage running system generates unnecessary vibrations, which adversely affects printing quality. Conventionally, the start-up time and start-up travel distance were increased, a dashpot was attached to the movable part of the tension unit that tensions the running wire, and a sliding member was constantly pressed against the movable part to provide braking force. Alternatively, a sliding member holder is fixed to the carriage, and the sliding member attached to the holder is pressed against a carriage traveling guide rail to apply a braking force to the carriage. However, the above-mentioned conventional techniques have drawbacks such as a decrease in printing speed, an increase in the size of the printer, an increase in carriage drive motion, and an increase in carriage drive energy.

The present invention has been made to solve the above-mentioned conventional techniques and drawbacks. In particular, when the carriage starts running,
The motor for driving the carriage is given excessive driving force at a predetermined timing to effectively apply braking force to the carriage, and the carriage can be brought to a steady running state quickly with a simple and inexpensive configuration. It was designed so that it could be done.

FIG. 1 is a schematic configuration diagram for explaining an example of a conventional printer scanning mechanism. In the figure, 1 is a carriage, 2 is a wire, 3 is a pulley, 4 is a carriage guide rail, 5 is a tension lever, and 6 is a Tension spring, 7 is lever fulcrum,
Reference numeral 8 is a motor (stepping motor) that drives the motor 8 to make the carriage 1 run when printing starts. It is necessary to provide a large acceleration force. However, the acceleration force at this time causes the tension spring system to vibrate, producing vibrations as shown in FIG. This vibration is a natural vibration determined by the carriage 1, wire 2, booth 3, lever 5, tension spring 6, etc., and has a vibration frequency f. (where M: total effective mass of carriage 1, wire 2, pulley 3, lever 5, etc.; K1: spring constant of tension spring 6).

FIG. 3 is a schematic diagram showing the main parts of an example of a conventional braking device for eliminating the above-mentioned vibrations, and as shown in the figure,
Although a braking member 9 is provided on the tension lever 7 of the printer mechanism shown in FIG. 1, this prior art also has the drawbacks mentioned above. "Figure 4 is a preliminary electrical circuit diagram for explaining one embodiment of the present invention, and in the figure, a stepping motor, a drive circuit,
1, n are time constant adjustment resistors, 231 to 234 are stepping motor coils (an example of four-phase excitation is shown),
U□~244 are stepping motor drive transistors,
5 is a voltage switching transistor, GA is an inverter, (9)
is the timing generation circuit -, and the stepping motor 8 is
As is well known, Stellar ring motor coil 231-2
34, stepping monitor drive pulses φ1·, φ2, Fl, and f2 are applied at the timing shown in FIG. 5, and the monitor is rotated.

Therefore, in the printer scanning mechanism as described above, the present invention generates a signal for opening 1 at a predetermined timing and at a predetermined time. During this period, a voltage V□ higher than the normal driving voltage V2 is applied to the pulse motor 8 through the transistor 5, and the undershoot and toe portions of the vibration waveform shown in Fig. 2 are applied. The carriage is designed to apply excessive driving force to the motor to prevent a decrease in speed (negative cycle of vibration).
As shown in the figure, undershoot Bl of vibration and dynamic waveform
In the section (see Fig. 6'(a)), the timing generating circuit inputs a signal qa (see Fig. 6(b)), and this signal a makes the transistor 5 conductive and connects it to the stepping motor coil. Higher voltage than the honorable voltage V2 ゛V□
is applied to give an excessive driving force to the motor that prevents the carriage speed from decreasing, so that the carriage start-up characteristics are as shown by the solid line in FIG. 6(C),
It is designed to quickly reach the idle speed.

7 and 8 are time charts for explaining other embodiments of the present invention, respectively. FIG. 7 shows an example in which excessive driving force is applied to the motor, and FIG. 8 shows an example in which excessive driving force is applied to the motor. ^This is an example in which the excessive driving force is gradually weakened.10 Figure 9 is a diagram showing an example of an electric circuit suitable for implementing the embodiment shown in Figure 8. )
The signals a (see Fig. 8(b)) and b (see Fig. 8(b)) are
e)), and control the transistors 31, 32, 33, operational amplifiers, etc. with these signals, and create the undershoot portion B1 of the vibration waveform shown in FIG. 8(a).
At B2 and -B3, a voltage C is generated that gradually decreases according to the R-C time constant determined by the resistor R and the capacitor C as shown in Fig. 8(d), and this signal C is applied to the stepping motor coil. It is designed so that it is applied to・Although each embodiment of the present invention has been described above, the stepping motor in the present invention is not limited to a four-phase excitation force type, and the timing generation circuit may be a known counter or mono It is easy to understand that it can be constructed by an electric circuit including a multi-channel circuit, or by program control using a 71 microcomputer.

Good morning.

As is clear from the above description, according to the present invention, with a simple and inexpensive configuration, when the carriage starts running,
The carriage can be brought into a steady running state in a short time and over a short running distance. □

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram for explaining an example of a conventional printer scanning mechanism, FIG. 2 is a drive characteristic diagram of the printer scanning mechanism shown in FIG. 1, and FIG. 3 is a diagram of a conventional printer scanning mechanism. A schematic configuration diagram of main parts for explaining an example of a control device in a scanning mechanism, FIG. 4 is a diagram of an electric circuit for this purpose, and FIG.
FIG. 4 is a waveform diagram of the pulse signal supplied to the stepping motor coil, FIGS. 6 to 8 are time charts for explaining the present invention in detail, and FIG. 9 is a diagram showing the waveform of the pulse signal supplied to the stepping motor coil. 1 is a diagram illustrating an example of an electrical circuit suitable for carrying out embodiments; FIG. 1... Carriage, 2... Wire, 3... Pulley, 4... Carriage guide rail, 5... Tension lever, 6... Tension spring, 10... Stepping motor, Stepping motor drive circuit, 231~ 234
...Stepping motor coil, addition/timing generation circuit 0 1 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (3)

[Claims] (1) A carriage, a wire for running the carriage, and a motor for driving the wire,
A printer scanning mechanism having a tension mechanism for applying tension to the wire, wherein an excessive driving force is applied to the motor at a predetermined timing at 9 o'clock when the carriage starts running. (2) The printer scanning mechanism according to claim (1), wherein excessive driving force is applied to the motor multiple times at predetermined timings. (3) Claims (1) or (2) characterized in that an excessive driving force is applied to the motor at a predetermined timing, and the excessive driving force is gradually weakened. Printer scanning mechanism as described in Section.