JPS591280A - Method for detecting home position of type wheel in wheel printer - Google Patents

Abstract

PURPOSE:To ensure the detection of a home position, by detecting a home position hole in a type wheel, stopping the wheel, performing the detection operation again after a specified time, rotating the wheel by every one character when the position is not detected, and performing the detection. CONSTITUTION:When a power source is turned ON, a pulse motor 3 is rotated so that a type part 4b is moved one by one, based on the control of a control circuit 14. A home position hole 9 of a type wheel 4 is checked by a light receiving element 10. When the hole is detected, the wheel is stopped. At the same time, a timer 22 is operated. After a specified time, the check is performed again. When the input from the light receiving element 10 is detected, a key signal input from a type key input part 16 is allowed. When the input is not detected, the pulse motor 3 is rotated by every one character again. When the hole is detected, the wheel is stopped, and the hole position is determined. In this way, the home position of the type wheel can be always detected positively.

Description

TECHNICAL FIELD OF THE INVENTION This invention relates to a method for detecting the home position of a type wheel in a wheel printer.

[Technical background of the invention and its problems]

Wheel printers set a home position on the type wheel, and for example, when the previous printing is completed, the type wheel is returned to the home position and waits for the next print, or when a print signal is input, the type wheel is temporarily returned to the home position. There is a method that searches for a character position corresponding to the input signal after returning the input signal. Therefore, in wheel printers, detection of the home position is an important factor in preventing erroneous printing.

Conventionally, in wheel printers, a hole is provided at the home position of the type wheel, and the type wheel is set at A? While rotating with the Luss motor, a photodetector searches for a hole, and when a hole detection signal is output from the photodetector, the Luss motor is stopped and home position detection is completed.

However, in reality, the vibration of the motor may cause the type wheel to move back by one character even if the hole in the type wheel rotates to a position where it can be detected by the photodetector. This may occur due to, for example, the printer stopping the type wheel before it has fully reached the home position. Therefore, in such a case, the type wheel cannot be correctly stopped at the home position, resulting in a problem of erroneous printing. For this reason, it is possible to increase the S/N ratio for home position detection by making the hole smaller, but if the hole is made too small, it will easily become clogged with dust, etc., making it impossible to detect the home position. .

[Purpose of the invention]

This invention was made to solve such problems, and an object of the present invention is to provide a method for detecting the home position of a type wheel in a wheel printer that can always and reliably detect the home position of the type wheel. .

[Summary of the Invention] This invention detects a hole provided at the home position of the type wheel and stops the rotation of the type wheel.
After that, the hole detection operation is performed again after a predetermined period of time has elapsed, and when a hole is detected again, the type wheel position is detected as the home position, and when no hole is detected again, the hole is detected. The type wheel is rotated completely by one character until the hole is detected, and the position of the type wheel when the hole is detected is detected as the home position.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a platen, and 2 is a printing unit.

The printing unit 2 includes a main pulse motor 3, a type wheel 4, a hammer drive mechanism 5, and the like. As shown in FIG. 2, the type wheel 4 is formed of a plurality of elastically deformable spokes 4a, each having a type portion 4b at the tip thereof. The type wheel 4 has each spoke 4a.
. . . A rotary board 6 whose rear end is fixed is fixed to the rotary shaft 7 of the reference motor 3 via the wind 8, and the type portion 4b is set at a home position in the middle of the rotary board 6. A hole 9 for home position detection is made at a position corresponding to the position. A light emitting element 10a is provided on one side with the hole 9 in between, and a light receiving element 1ob is provided on the other side.
has been established. In addition, 11 in the figure is in-clean, 12.1
3, the paper is ID.

FIG. 3 is a block diagram showing the main circuitry. A control circuit 14 is provided, and the light receiving output of the light receiving element 10 is inputted to the control circuit 14 via an input port 15, and each of the letters of the letter wheel 4 is provided with a control circuit 14. The input port 17 receives key signals from the print key manual section 16 provided corresponding to the sections 4b, . . .
I am entering it through. The control circuit 14 also has an output/
- a drive circuit 19 of said pulse motor 3 via a toll;
It also controls the solenoid 21 of the hammer drive mechanism 5 via the output port 20. The control circuit 14 also controls a timer 22.

The control circuit 14 performs control based on the control program shown in FIG. 4, and when the power is turned on, it first controls the motor drive circuit 19 to drive the pulse motor 3 for one character, that is, for one character portion 4b. The input of the light reception output from the light receiving element 10 is checked every time the rotation is made. When the basic light output of the light receiving element 10 is input through the input port 15, the rotation of the pulse motor 3 is controlled to stop, and the timer 22 is operated, and after a predetermined time elapsed when the timer 22 times up, the light output from the light receiving element 10 is inputted again. Check the input of the received light output.

When the light reception output is input again via the input port 15, input of a key signal from the print key input unit 16 is permitted. If there is no input of the light reception output again, the motor drive circuit 19 is controlled again to stop the pulse motor 3 from rotating by one character while checking the input of the light reception output from the light receiving element 10. Then, when there is an input of the light receiving output, the above-mentioned
l? The rotation of the pulse motor 3 is controlled to stop, and the input of a key signal from the print key input unit 16 is permitted.

When a key signal from the type key manual unit 16 is input, the pulse motor 3 is rotated by the motor drive circuit 19 so that the corresponding type part is set at the No. 1 marker position, and then the no. 1 mer drive machine wt5 solenoid 2
1 is energized to perform a type printing operation. Thereafter, the rotation of the nozzle motor 3 is controlled so that the light receiving element 10 detects the hole 9, that is, the home position is detected.

In the embodiment of the present invention in which tlE is performed in this manner, when the light receiving element 10 detects the position of the hole 9, the rotation of the main pulse motor 3 is controlled to stop. When the type wheel 4 is correctly stopped at the home position, the light-receiving element 10 detects the hole 9 even after the elapse of a predetermined time set by the timer 22, so at this time, the printer waits for desired type printing by manual input of the type keys. However, when the light receiving element 10 detects the position of the hole 9 and stops the rotation of the printer 3, the stop position of the type wheel 4 may deviate from the home position due to the vibration of the motor 3. At this time, the hole 9 will not be detected again after the predetermined time period determined by the timer 22 has elapsed. Then, the Noculus motor 3 is rotated one character at a time again to detect the hole 9, and when the hole 9 is detected, the rotation side of the pulse motor 3 is stopped and the printer waits for the desired character to be printed manually by the character key.

In this way, even if the home position is detected once by the hole 9, the home position is not immediately determined to be the correct home position, but the home position detection operation is performed again after a predetermined period of time has elapsed. If the home position is determined to be the home position, and the home position is not detected at the time of re-detection, the no. When the home position is detected, it is determined to be the correct home position, so even if the type wheel 4 deviates from the home position and stops due to the vibration of the motor 3 when the home position is detected for the first time, the type hole 4 will eventually be correctly located at the home position. can be stopped. Therefore, the type wheel 4 can always be correctly stopped at the home position, and there is no risk of erroneous operation of type printing by manual input of the type keys.

Incidentally, in the above embodiment, when the type wheel is stopped at the home position and the type key is pressed manually, type is printed, and then the type wheel is stopped at the home position again, but this is not necessarily limited to this. Instead, the home position of the type wheel may be detected after manual input of the type key, and then the type printing may be performed.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a method for detecting the home position of a type wheel in a wheel printer, which can always and reliably detect the home position of the type wheel.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a side view schematically showing the main parts, Fig. 2 is a front view of the printing ml-rule,
Figure 3 is a block diagram of the main parts, and Figure 4 is a flowchart showing the control routine of the control circuit in Figure 3. 3...Mother motor, 4...Type wheel, 9...
・Hole, 10a... Light emitting element, 10b... Light receiving element,
14... Control circuit, 22... Timer. Applicant's agent Patent attorney Takehiko Suzue 1 Figure 1 Figure 3

Claims (1)

[Claims] In a wheel printer in which a hole is provided at the home position of a type wheel, the home position is detected by detecting the hole, and a predetermined type position is searched based on the home position to perform a printing operation. Controlling the rotation of the type wheel to stop, and then performing the hole detection operation again after a predetermined period of time has elapsed;
When a hole is detected again, it is set as the home position, and when no hole is detected again, the type wheel is rotated one character at a time until the hole is detected, and this rotation control is performed. A method for detecting a home position of a type wheel in a wheel printer, characterized in that when a hole is detected, the home position is set as the home position.