JPH0374327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary shaft position detection device, and more particularly, to an improved device for detecting each stop position of a rotary shaft whose rotation is controlled to a plurality of preset stop positions at a predetermined rotation speed. It is related to.

Correct control of predetermined stopping positions in various motor-driven mechanical devices is extremely important, and plays an important role in tool selection in machine tools, platen positioning in various printer devices, and the like.

FIG. 1 shows a schematic configuration of a printer device equipped with a rotating shaft position detecting device, and the rotational driving force of a motor 10 is transmitted to a printer mechanism 1
4 has been transmitted. The printer mechanism 14 is provided with a platen 16, and a printer head 18 performs desired printing on recording paper mounted on the platen 16. The rotational driving force of the clutch 12 is supplied to the platen 16 via a reduction gear train 20.

The clutch 12 is brought into an engaged state by the excitation of the clutch solenoid 22, and once the clutch 12 is engaged, it continues to be engaged to a predetermined position even after the clutch solenoid 22 is de-energized. The engagement state is mechanically released when the desired operation of the various mechanisms 14 is completed.

A control section 24 is provided to control desired operations of the motor 10, clutch 12, and various mechanisms 14 of the printer, and desired operations are performed in response to command signals from the control section 24.

In the illustrated printer device, the platen 16 has three stop positions: a home position and two printing positions where predetermined printing is performed. It includes a first printing position and a second printing position for printing on sheet paper, bankbooks, etc., and is selectively switched as necessary.

In order to determine each rotational position of the platen 16,
This printer device is provided with a camshaft 26, and a cam group 28 fixed to the camshaft 26 mechanically controls each part of the platen 16 corresponding to each printing position. camshaft 2
The position of the rotary shaft 6 is electrically detected and supplied as a rotary shaft position signal to the control section 24, and a desired printing operation is performed.

In order to detect the rotational axis position of the camshaft 26 with the rotational axis extended, a position detection plate 30 is usually fixed to the camshaft 26, and a slit, a magnet, a reflective part, etc. are attached to the circumferential surface of the position detection plate 30. A mark sensor provided near the position detection plate 30 reads and detects each mark position corresponding to each predetermined stop position. Usually, these mark sensors are photoelectric type or electromagnetic type sensors, and in FIG. 1, a slit mark is provided on the periphery of the position detection plate 30, and the slit mark is formed by the light emitters 32a, 32b and the light receivers 34a, 34b. Detected.

As described above, when the camshaft 26 controls three stop positions corresponding to the three stop positions of the platen 16, the position detection plate 30 also has three slit mark positions on its periphery, and these three types In order to correctly detect and determine the stop position of the
Each stop position must be correctly detected and determined based on the combined signals of these sensor pairs.

Therefore, such a conventional device requires a large number of sensors, which causes an increase in the size and price of the device.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a rotation system that is small, lightweight, inexpensive, and capable of reliably determining multiple stop positions of a rotating shaft using a single sensor. An object of the present invention is to provide an axis position detection device.

In order to achieve the above object, the present invention provides a mark that rotates integrally with the rotary shaft to stop the rotary shaft rotating at a predetermined angular velocity at a plurality of predetermined positions, and for determining the predetermined stop position. In a rotary shaft position detection device that has a position detection plate equipped with a mark sensor and detects a stop position by determining the position of the detection plate using a mark sensor, the detection plate has a plurality of sensors arranged on the same circumference at predetermined angular intervals. The mark sensor consists of a single sensor that detects the presence or absence of a mark as the position detection plate rotates, and sends out this detection pattern as a mark pattern, and a mark pattern memory storing corresponding reference mark patterns, and a pattern determination circuit that compares the detected mark pattern and the reference mark pattern corresponding to a desired stop position to determine whether they match. It is characterized by having the following.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an embodiment in which the device of the present invention is used to detect the position of the platen of a printer.
As in the conventional device shown in FIG. 1, the camshaft is composed of a camshaft that rotates in conjunction with the platen, and can be controlled by the rotational position of the rotational shaft 40 of each drive mechanism of the printer.

A position detection plate 42 is fixed to the rotating shaft 40, and the position detection plate 40 is made of a thin opaque plate such as metal or plastic, as shown in FIG. Marks are provided corresponding to the positions, and in the position detection plate 42 in the embodiment, these marks are made of slits.

The stopping position in the example is home position 1
00, a first printing position 102 for continuous paper, and a second printing position 104 for printing on bankbooks, etc., and different types of slits are provided depending on each stop position. That is, for the home position 100, one slit 44 is located at the first
Two slits 46 for printing position 102
a, 46b, and two slits 48a, 48b for the second printing position 104.

As is clear from FIG. 2, in the present invention, a single mark sensor 50 is provided for the position detection plate 42, and the mark sensor 50
are each slit 44, 46, 48 of the position detection plate 42.
It is composed of a light receiver that electrically detects the light, and can output a desired electrical signal in response to reception and shielding of light from the light emitters 52 disposed opposite to each other with the position detection plate 42 in between.

As described above, in the present invention, only the single mark sensor 50 is provided to detect the stop position of the position detection plate 42, but in this type of device, the rotating shaft 40 is normally Since it rotates at a constant speed and its stopping position is set in advance, the combination of the detection signals from the mark sensor 50, that is, the mark pattern and the time information of the mark pattern determined by the rotational speed of the rotary shaft 40, is detected. By comparing it, it is possible to determine which position the device has stopped at, and to determine whether or not the rotating shaft 40 has correctly rotated to a predetermined stopping position, thereby detecting the current position of the device. It becomes possible to perform confirmation or error detection extremely easily.

4A to 4C show the mark pattern detected by the mark sensor 50 when the position detection plate 42 rotates once, and when the mark sensor 50 faces the slits 44, 46 and 48, the level " A signal of "H" is obtained. As is clear from FIG.
The reference mark pattern obtained in cooperation with 0 is different for each stop position, thereby making it possible to correctly discriminate each stop position.

The mark patterns A, B, shown in FIG.
C is stored in the mark pattern memory 54 in FIG. 2 in the embodiment, and each pattern can be discriminated by comparing this reference mark pattern with the detected mark pattern which is the output signal from the mark sensor 50. can. In the embodiment, a pattern determination circuit 56 is provided, and depending on whether the next printing will be for continuous paper or for passbooks, the rotation axis will print at either the first printing position or the second printing position. Since the stop position designation signal specifies whether to select positions 102 or 104, the pattern determination circuit 56 determines the reference mark pattern corresponding to this stop position designation signal from the current start position and stores it in the mark pattern memory. 54 and compares this reference mark pattern with a detection mark pattern which is a detection signal from the mark sensor 50 obtained by rotation of the rotation shaft 40, and determines whether this stop position is correctly specified at the next stop position of the rotation shaft 40. If the result is negative, an error signal is output.

As described above, according to the present invention, the rotating shaft 4
0 is rotated correctly, the rotation axis 4
It is possible to correctly determine whether or not the stop position of 0 is a designated stop position, but in addition to this, in the present invention, it is also possible to determine whether or not the rotating shaft 40 is being rotated correctly by time determination. For this purpose, in the exemplary embodiment, a starting signal is supplied to the pattern determination circuit 56, and a timing signal from a clock generator 58 forming a timer is likewise supplied to the pattern determination circuit 56. .

The starting signal can normally be an excitation signal sent to the clutch solenoid 22, and since the rotating shaft 40 should start rotating with the excitation of the solenoid, the starting signal is determined at a predetermined rotational speed of the rotating shaft 40 from the time of starting. When a signal determined by each pattern shown in FIG. 4 cannot be obtained after the elapse of a certain period of time, the pattern determination circuit 56 outputs an error signal. These time determinations may be performed by comparing all cases of rising and falling signals of each pattern A, B, and C, or by comparing and determining any selected rising or falling time. It is also possible to do this.

As described above, according to the present invention, it is possible to accurately detect the stop position of the rotary shaft by using both the comparison of each mark pattern and the time judgment only by using a single mark sensor. It greatly contributes to the reduction in size and weight.

Note that although the marks on the position detection plate in the embodiment are made of slits, they can also be made of magnets or reflective plates, and the mark sensor can be not only a photoelectric type but also an electromagnetic detection type element. Furthermore, according to the device of the present invention, the number of stop positions set on the outer periphery of the position detection plate can be set arbitrarily.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a printer device having a rotating shaft, FIG. 2 is a schematic diagram of main parts showing a preferred embodiment of a printer device to which a rotating shaft position detection device according to the present invention is applied, and FIG. FIG. 4 is a plan view showing a preferred embodiment of the position detection plate according to the present invention, and is an explanatory diagram of the mark pattern in the present invention. 40... Rotating shaft, 42... Position detection plate, 44...
...Slit, 46a, 46b...Slit, 48
a, 48b...Slit, 50...Mark sensor, 54...Mark pattern memory, 56...Pattern judgment circuit, 58...Clock generator, 10
0... Home position, 102... First printing position, 104... Second printing position.

Claims (1)

[Scope of Claims] 1. A position that rotates together with the rotating shaft to stop the rotating shaft rotating at a predetermined angular velocity at a plurality of predetermined positions, and is provided with a mark for identifying the predetermined stopping position. In a rotating shaft position detection device that has a detection plate and detects a stop position by determining the position of the detection plate using a mark sensor, the detection plate is provided with a plurality of types of marks at predetermined angular intervals on the same circumference. The mark sensor is comprised of a single sensor that detects the presence or absence of a mark as the position detection plate rotates and sends out this detection pattern as a mark pattern, and the mark sensor is configured as a reference corresponding to each of the plurality of stop positions. A rotating shaft comprising: a mark pattern memory that stores mark patterns; and a pattern determination circuit that compares the detected mark pattern and the reference mark pattern corresponding to a desired stop position to determine whether they match. Position detection device.