JPS6099657A - Type body controller for printer - Google Patents

Abstract

PURPOSE:To prevent misprinting due to a step-out by providing a means of detecting an inertial moment of a type body to adjust the drive pulse of a stepping motor. CONSTITUTION:Separate ROM tables in which two kinds of drive pulse interval information is stored for a stepping motor M are provided corresponding to a type body different in the inertial moment. The motor M is rotated and then, the type body is stopped at a specified rotary angle to detect the attenuation in the vibration of the type body. When the value of the amplitude is larger than a certain value after a specified time, one ROM table is switched over to the other.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention also provides a daisy-wheel type typeface.
Regarding serial printers that use a stepping motor to select type, it is especially important to set the stepping motor drive table (PI
This invention relates to a type system I, Il+ device for a printer designed to be 5n.

Conventionally, in printers with dage wheel type typefaces, stepping motors are used to drive the typefaces in order to accurately determine the rotation angle of the typefaces, but the drive angle is constantly detected to prevent synchronization. There is a closed-loop control method that immediately corrects the step-out by applying feedback when such a problem occurs, and an open-loop control method that does not perform such control. A loop control method is usually employed.

Now, in order to suppress damping of rotor vibration in a stepping motor, it is necessary to supply the stepping motor with drive pulses with a pulse interval that matches the IW moment of the load. In printers that drive
If the type body is replaced by one with a different moment of inertia, the interval between the drive pulses must be adapted to the moment of inertia of the type body.

However, conventionally, printers have not been equipped with a means to measure the moment of inertia of the typeface, and for this reason, when an operator uses a typeface with a moment of inertia that does not match the pulse width of the drive pulse, the rotor of the stepping motor The disadvantage is that the vibration increases, causing step-out and erroneous printing.

This invention was made by focusing on this drawback,
It is an object of the present invention to eliminate the above-mentioned drawbacks by providing a means for detecting the moment of inertia of a type body using a simple (1η configuration) in a printer that drives a stepping motor using an open-loop control method.

Hereinafter, with reference to the drawings, a detailed explanation of the present invention and the first
In the figure, 1 is the platen, 2 is parallel to the platen 1,
This is a carriage movably supported on the machine frame in conjunction with a drive source (not shown). M is a stepping motor, and a drive shaft 3 is placed on a carriage 2 so as to face the platen 1, and a daisy-wheel type type body 4 is removably attached to the tip Q thereof. 5 is a U-shaped frame with a light emitter and a photoreceptor P disposed vertically facing each other and placed on the carriage 2; Third
The structure is such that the light emitting body of the frame 6 and the light receiving body P are cut off by a solid line in the figure.

Next, the control circuit of this embodiment will be explained.

In FIG. 4, the CPU is a central processing unit with arithmetic and input/output functions, the RAM is a dynamic storage circuit with a plurality of arbitrarily addressable memories, and the ROM is a control program and drive pulses for the stepping motor M, which will be described later. This is a static memory circuit that stores the table. DR is a drive circuit for controlling the stepping motor M based on a command from the CPU; SW is a manually operable start switch A of this control circuit; 110 is an amplifier for amplifying the detection signal of the photoreceptor P; is the CPU, drive circuit DR, and start switch S.
W and amplifier A.

Next, a drive table for the stepping motor M provided in the ROM will be explained.

Now, Figures 5.6.7 respectively show the starting, constant speed, and stopping modes of the stepping motor. Rain the time chart,
X is the time chart of each excitation phase to drive the type body with a small moment of inertia, and Y is the time chart of the drive pulse for each excitation phase to drive the type body with a large moment of inertia. This is a time chart.

In other words, the startup mode for both X and Y (Figure 5)
accelerates the stepping motor by gradually narrowing the interval between drive pulses; in constant speed mode (Figure 6), the interval between drive pulses is kept constant; in stop mode (Figure 7), the interval between drive pulses is gradually narrowed. 9. slowing down the stepper motor by widening it, thus preventing sudden speed changes to the stepper motor; However, as shown in the figure,
The appropriate drive pulse width when the moment of inertia of the typeface is small is narrower than when the moment of inertia of the typeface is large. In other words, there is a unique optimal drive pulse width corresponding to the moment of inertia. Figure 8 shows the predetermined starting, constant speed,
This is a time chart for damping the vibration of each type when driving or stopping type bodies with different moments of inertia attached to a stepping motor under the stop mode, and (I) is a time chart that is adapted to the driving pulse. When a type body with a moment of inertia larger than the moment of inertia that matches the drive pulse is attached, (II) becomes (
2) Just adapt to the driving pulse. In other words, as shown in the figure, when the +rt moment of the type body matches the drive pulse, the vibration of the type body attenuates extremely quickly, but when the moment of inertia of the type body is larger than the value that matches the drive pulse. Even if the vibration is small, the damping of vibrations in the typeface will be slow.

Therefore, considering the minimum moment of inertia (IO) and the maximum moment of inertia (IO) of the plurality of typefaces used in this printer, various drive pulses with different pulse intervals were set to drive the stepping motor M. After stopping, the amplitude of the printed letters after a certain reference time of 70 seconds was measured for a plurality of printed letters having different moments of inertia. Then, Fig. 9 α
, β curves, the width of the drive pulse is selectively optimized to the moment of inertia of the typeface) I2 or the moment of inertia of the typeface) 1B. It has been found that by setting this setting, it is possible to suppress the amplitude of the typefaces to below the permissible amplitude Am that does not cause stepping motor step-out or misalignment of the printing position for all typefaces in the range of 0 to xx. Ta.

Based on this, the information on the drive pulse width optimized for the moment of inertia) I2 and the moment of inertia (8) is sequentially stored in the ROM as tables X and Y in the starting mode, constant speed mode, and stop mode. stored at the address.

Below Margin Next, we will explain the CPU control program for setting one of the tables X and Y in the ROM.
In FIG. 0, when the power is turned on using the switch SW, table X in the ROM is set. Next, the data of this table The driving pulse (see FIG. 6) is supplied, and the stepping motor M enters constant speed driving.

Next, it is determined whether the photoreceptor P is off, that is, whether the detector 6 is interposed between the light emitter and the photoreceptor P. still,
The range in which the photoreceptor P is turned off is set to be equal to the amplitude Am shown in FIG. If the photoreceptor P is on, the stepping motor M continues to be driven at a constant speed, and if the photoreceptor P is off, the drive pulse of the stop motor 1' (see Figure 1) is supplied to the stepping motor, and the stepping motor M is driven at a constant speed. When the motor M stops, the CPU timer is reset. In this way, the counting power of the timer has decreased, and it is determined whether the H1 number 11'L is a predetermined value To (to exceed 9 in Figure 11) or not. . If the photoreceptor ■] turns on even once, the ROM table setting will be switched from X to Y, but for a predetermined time Tt()
After To), the program ends regardless of whether or not the photoreceptor P is detected to be on.

In the above configuration, the table setting operation of the ROM will be explained.

First, the typeface 4 is mounted on the drive shaft 3. At this time, it is assumed that the moment of inertia of the typeface 4 is between IO and 11 in FIG. When the switch sw is operated, the CPU
Table X in the ROM is set by . Next, the startup mode (fifth
The drive pulse shown in the figure) is generated and supplied to the stepping motor M, and the stepping motor M starts driving, so that the typeface 4 begins to rotate. Next, the 7E motion y in constant speed mode (Fig. 6) is determined by the pulse interval based on Chiol X:
A signal is created and supplied to the stepping motor MIC,
The stepping motor M enters constant speed drive. In this way, the drive shaft 3 of the stepping motor M is rotated in the direction of arrow R (Fig. 3).
When the drive shaft 3 reaches a rotation angle at which the detection body 6 blocks the space between the light emitters P, a drive pulse for the stop mode (FIG. 7) is supplied to the stepping motor M, and the CPU
timer is reset. In the stop mode, the stepping motor M stops driving, but due to the moment of inertia of the type 4 and the stepping motor M, the type 4 is in an area where the detector 6 turns off the photoreceptor P, as shown in FIG. Damped oscillation is performed centering on H. Accompanied by the damped vibration, the detection body 6 crosses between the photoreceptor P and the light emitter, and the photoreceptor P turns on and off each time.

Now, if the magnitude of the moment of inertia of the type 4 currently attached is 14 (Fig. 9), the amplitude of the type 4 after the reference time To is Aml (Fig. 9), which is Aml (Fig. 9). Therefore, after To, there is a moment when the sensing body 6 moves from between the photoreceptor P and the light emitter, and the mourning light body P turns on. Then, the ROM table changes to
It can be switched from to Y. When the printing operation starts after the table is switched to Y, as shown in FIG. The misalignment of the printing position does not increase.

In addition, as the typeface 4, the moment of inertia I5 (Fig. 9)
When this is attached to the drive shaft 3 of the stepping motor M and the switch SW is operated, the ROM table X is set again and the above operation is repeated, but in this case, the ninth (8) As shown, the typeface 4 after the reference time To
Since the amplitude Am3 is smaller than the allowable amplitude Am, the time chart of the amplitude becomes as shown in FIG. 11, and the table X in the ROM cannot be switched. That is, when the printing operation is started after this, since hrn8<hm, the stepping motor M does not step out of step and the printing position deviation does not increase significantly.

As described above, according to the present invention, in a printer in which a type body is driven by an oven-loop-controlled stepping motor, two types of stepping porters are provided which face the type body of different 1 kan'11:moment. Record driving pulse interval information 1. A separate ROM table is prepared in advance, and the type body is rotated by a stepping motor, stopped at a predetermined rotation angle, the attenuation of the vibration of the type body is detected, and the amplitude is changed after a predetermined period of time. When the value is larger than a certain value, the ROM table is cut from one side to the other (moxibustion), so the stepping motor drive pulse interval is automatically set to match the moment of inertia of the typeface. Therefore, step-out of the stepping motor can be suppressed, and the printing position can be maintained appropriately.

Furthermore, since the stepping motor can be controlled in an open loop, its drive circuit can be simplified and costs can be reduced.

In the above embodiment, the rotation angle of the drive shaft 3 is detected by the U-shaped frame 5 and the detection body 6.
The rotation angle may be detected by a rotary encoder in which a circular plate is fixed to and provided with a plurality of slits or a single slit.

In addition, in the above embodiment, only one sensing body is provided, but in order to improve the detection accuracy of the sensing body, a plurality of sensing bodies are fixed to the drive shaft of the stepping motor at different phase angles.
A plurality of frames 5 corresponding to these plurality of detection bodies are arranged on the machine frame, and the rotation angle of the drive shaft is detected when all the light receiving bodies of each frame 5 are off. Good too.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the main parts of the stepping motor with type attached, Figures 2 and 3 are diagrams of the detection state of the rotation angle detection means of the drive shaft, and Figure 4 is a block of the control circuit. Figures 5 to 7 show the start-up and
A time chart showing the drive pulses in constant speed/stop mode and the step drive of the stepping motor due to the drive pulses,
FIGS. 8(I) to (IID) are time charts showing the attenuation of vibrations of type bodies with different moments of inertia for predetermined drive pulses; FIG. Figure 10 is a flowchart of the CPU program, and Figures 11 and 12 are diagrams showing the detection state of the detection means for the vibration of the typeface. 1.・Platen, 2... Carriage, M... Stepping motor 3... Stepping motor drive shaft 4... Typeface, 5, 6.r,, p... Detection means,
DR...driving means, ROM...storage means, CPU.
...Address means, control means Name of applicant Tokyo Heavy Equipment Industry Co., Ltd. Figure 4 Figure 10 Figure 11 Figure 11 41 Motion Skunf 0 Figure 12

Claims (1)

[Claims] A stepping motor whose drive shaft is arranged to face the platen, a plurality of protruding fils extending radially from the central part, and an i-point 9.
Types are formed on each of 1"1"d and can be attached to and detached from the drive shaft of the center case tempering motor. In a printer that prints by installing one of them on the drive shaft of a stepping motor, information on the drive pulse trains of two types of stepping motors with different pulse intervals that are compatible with type bodies with different moments of inertia can be collected. A storage means having two memory tables each stored in sequence; an address means configured to read the stored information in one of the two memory tables sequentially; A driving means that creates a drive pulse with a tl sea and supplies it to the stepping motor, and detects the constant rotation angle range of the type body attached to the stepping motor, and the type body records the rotation angle 1. A detection means that generates an in-area signal when the device is within the area and an out-area signal when it is outside the area, and a stepping motor which is set in advance for a predetermined time and generates an in-area signal when the area is outside the area. control means (1) for acting on the addressing means to switch the setting of the memory table to the other in connection with the occurrence of out-of-range (a) and (i) after a predetermined time period from that time; Printer type control device equipped with.