JPS6410351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static printer with a type wheel, and more particularly to a printer with a device for detecting malfunctions in type selection operations.

The type wheel in a static printer is
In general, there are two types in which the rotation or stop is controlled by a stepping motor, and one type in which the driving force of a continuously rotating DC motor is selectively transmitted to the type wheel using a transmission means such as a clutch. There is a type that controls rotation and stopping. In the former case, since a stepping motor is used, the rotation and stopping of the motor can be controlled relatively accurately, but in the latter case, the DC motor is continuously rotating, so the clutch, etc. If the transmission means did not operate effectively, there was a risk that the type wheel would not stop at a desired position or would continue to rotate, resulting in a malfunction.

The object of the present invention is to provide a highly reliable printer by equipping a so-called stationary printer with a malfunction detection device, which is equipped with the above-mentioned DC motor and transmission means such as a clutch. One example will be explained.

FIG. 1 shows a schematic configuration of the main parts of a printer according to the present invention, and particularly shows a type selection mechanism. The type wheel 1 has a large number of type characters on its periphery, is rotated by a rotating shaft 2, and is stopped when the type desired to be printed faces a hammer 3, and the hammer 3 completes the printing. It is becoming more and more common. The rotating shaft 2 is connected to a DC motor 5 via a spring clutch device 4, and the spring clutch device 4 selectively transmits the rotational force of the continuously rotating DC motor 5 to the rotating shaft 2. The spring clutch device 4 consists of two spring clutches 7 and 8 controlled by a control lever 6 driven by an electromagnet (not shown). Since the principle of the so-called spring clutch device is well known, its explanation will be omitted, but please note the winding direction of the coil springs 9 and 10 in the figure. That is, the coil springs 9 and 10 are wound in opposite directions and operate differentially. In other words, now,
It is assumed that the motor 5 and the gear 11 are rotating in the direction of the arrow in the figure, and the switching arm 6a of the control lever 6 engages with the notch 12a of the locking plate 12,
Moreover, when the switching arm 6b is not engaged with the actuating ratchet 13 [see FIG. 2], the gear 1
Coil spring 9 between 1 and actuating ratchet 13
acts to tighten the cylindrical bodies 11a and 13a, while the coil spring 10 between the gear 11 and the locking plate 12 relaxes because rotation of the locking plate 12 is inhibited. As a result, the rotation of the gear 11 is transmitted only to the actuating ratchet 13 and not to the locking plate 12. In addition,
The rotating shaft 2 includes a hollow cylindrical body 12c fixed to the locking plate 12, the gear 11, and the actuating ratchet 13;
It passes through 11a', 11a and 13a and is fixed to the actuating ratchet 13. On the other hand, in the opposite state to the above, that is, the switching arm 6b of the control lever 6
is engaged with the ratchet of the actuating ratchet 13, and the switching arm 6a is engaged with the notch 12a of the locking plate 12.
When the gear 11 is disengaged from the locking plate 12, the rotational force of the gear 11 is transmitted only to the locking plate 12, and the rotational force of the gear 11 is transmitted only to the locking plate 12.
It is never transmitted to

As described above, in the printer of the present invention, the rotational force of the continuously rotating DC motor 5 is selectively transmitted to the rotating shaft 2 by the clutch means 4 to select the type desired to be printed. . For details of the printer, if necessary,
Please refer to Japanese Patent Application No. 54-105673.

Reference numeral 14 is a detection disk provided to rotate together with the actuating ratchet 13 and provided with a conductive pattern, and detection sliders 15, 16 and 17 are in sliding contact with the disk surface. This detection disk 1
4 constitutes a detection device for detecting the position of the type characters on the type wheel 1, and has a one-to-one relationship with the number and position of the type characters.
A plurality of radial conductive patterns 14a corresponding to
[13 in this embodiment] and common pattern 1
4b is provided. Reference numeral 119 denotes an actuator for driving the control lever 6, which is not shown in the figure, but is actuated in the direction of the arrow in the figure when the electromagnet is excited.

Next, the operation of the above printer will be explained with reference to FIG. 1 and the timing chart shown in FIG. 3. Now, when you try to print the character "6" on type wheel 1, first the power is turned on and the third
As shown in Figure a, the motor drive signal is turned ON, and the rotation of the motor 5 is transmitted to the rotating shaft 2 via the idle gear 20, gear 11, and actuating ratchet 13, and the type wheel 1 and detection disk 14 begin to rotate. Accompanying this, as shown in FIG. 3b, a pulse signal indicating the position of the printed character is continuously obtained from the detection disk (printed character position detection device) 14. The rising timing of each pulse signal is set when the slider 15 and the common slider 16 are electrically connected, and the falling timing is set when the slider 17 and the common slider 16 are electrically conducting. It has been done. In the case of the present invention, since there are 13 types provided on the periphery of the type wheel 1, if the sliders 15 and 17 are arranged on a straight line passing through the center of the disk as shown in FIG. , the opening angle α is 27.69 degrees, and the opening angle β is
27.69/2 degrees, and one cycle of pulses is generated every time the detection disk 14, ie, the type wheel 1, rotates 27.69 degrees. When the type wheel 1 rotates, the zero position of the type is then detected (FIG. 3c).

This zero position is detected when the slider 18 and the common slider 16 are electrically connected. When the zero position is detected, the control position (not shown) can identify whether the pulse from the character position sensing device 14 corresponds to the character "5" immediately before the character "6" to be printed. At the moment the pulse is detected, at its rising edge, an electromagnet (not shown) of the actuator 19 for driving the control lever 6 is energized in order to switch the spring clutch 4 to stop the type wheel 1 (FIG. 3d). ]. The actuator 19 and the spring clutch 4 operate with a slight time delay, and in FIG. The printed character "6" stops facing the hammer 3. At the same time, the print position detection device 14 detects the print character "6".
The pulse corresponding to 1 is generated, and when the pulse rises, the electromagnet is de-energized (FIG. 3d), but the actuator 19 still maintains its position. That is, in FIG. 1 or FIG. 2, when the switching arm 6a of the control lever 6 separates from the notch 12a of the locking plate 12, the tip of the arm 6a comes into sliding contact with the outer periphery of the locking plate 12, and the tip The other switching arm 6b is forced into engagement with the ratchet of the actuating ratchet 13 until it re-engages with the next notch 12b, i.e. until the locking plate 12 has turned half a turn, during which time the type wheel 1 is The rotation is stopped and the type “6” is printed by hammer 3.
is printed statically [Fig. 3 f]. Thereafter, the printing operation is performed in the same manner, and furthermore, the carriage return and paper feeding operations are performed to complete the printing of one line, but since it is not directly related to the present invention, the explanation will be omitted. If necessary, the above-mentioned patent application 1974-
Please refer to No. 105673.

As described above, if the printer operates normally, as shown in Figure 3, when the desired type, for example, "6" is accurately selected and the type wheel 1 is stopped, the electromagnet 3d), no pulses are generated from the type position sensing device 14, and the control lever remains open for a certain period of time, as shown in FIG. 3b, i.e., in FIG. Until the tip of the switching arm 6a of 6 engages with the next notch 12b of the locking plate 12, in other words, the locking plate 12 rotates half a turn, the clutch means 4 switches again, and the actuation latch 13 resumes rotation. No pulse is generated until this happens [area A in FIG. 3a].

Next, a case where a malfunction occurs will be explained. Malfunctions in this type of printer occur, for example, when the power supply voltage drops and the electromagnet for switching the clutch means 4 does not operate completely. Figure 4 shows a malfunction in which when the character "6" is selected in the same way as in Figure 3, the response of the electromagnet is delayed due to a drop in the power supply voltage, resulting in the character "7" being selected. Shows the time chart when this occurs. In addition, in FIG. 4, only the type position detection signal [FIG. 4 a] and the electromagnet drive signal [FIG. 4 b] are shown. As can be seen by comparing FIG. 4 with FIG. 3, when a malfunction occurs, a signal E from the character position detection device 14 is recognized in a region A where the output should originally be a constant value. This example is an example of a malfunction in which the wrong type was selected, but another example could be a malfunction in which the type wheel 1 continues to rotate because the electromagnet does not operate at all. In this case, since the clutch means 4 do not switch at all, the type wheel 1 does not stop, so that a phenomenon occurs in which the area A is entirely a continuous pulse.

The above-mentioned malfunction can be detected by detecting the state in which the character position detection signal is once turned OFF and then turned ON in area A shown in FIG.

FIG. 5 shows yet another example of a malfunction in the character selection operation. This example is a malfunction that can occur when there is a misalignment in the positional relationship between the actuating latch 13, the detection disc 14, and the type wheel 1 in FIG. 1, and as in the case in FIG. In this example, when the user selects the character "5", the printed character "5" is selected. In this case, as shown in Fig. 5, the moment the type character "5" is selected, the type wheel immediately stops, so as shown in Fig. 5a,
The pulse from the type position detection device 14 is turned ON immediately.
It will remain as it is. On the other hand, as mentioned above,
The electromagnet drive signal is the rise of the type position detection signal.
Since it is turned OFF, in this case it is not turned OFF and is continuously maintained in the ON state as shown in FIG. 5b.

In order to detect this type of malfunction, as can be seen from Figures 3 and 5, the electromagnet drive signal [Figure 5b] must be activated after a certain period of time after the electromagnet is driven.
All you have to do is check whether it has turned OFF or not, and if the ON state continues, you can judge that it is malfunctioning. Further, after the pulse corresponding to the printed character "5" is generated in the printed character position detection device [Fig. 5 a], the pulse shown in Fig. 4 a
It is also possible to monitor the occurrence of a pulse corresponding to the pulse c corresponding to the printed character "6" in , and determine that a malfunction has occurred if this does not occur.

FIG. 6 is a block diagram of a malfunction detection circuit for detecting the malfunction described above, in which an electromagnet drive signal M is inputted to an input terminal 20a, and a type position detection signal W is inputted to an input terminal 20b. The electromagnet drive signal M and the type position detection signal W are sent to NOT gates 21 and 22, respectively.
The output of the AND gate 23 becomes one input of the AND gate 24. The electromagnet drive signal M further serves as a trigger input for the first one-shot multivibrator 25, and the output of the one-shot multivibrator 25 serves as the other input of the AND gate 24. The output of this AND gate 24 serves as a trigger input for a second one-shot multivibrator 26.

The above configuration is for detecting the state in which the type position detection signal W changes from ON to OFF after the electromagnet is driven, that is, the point P in FIG. 4a. The first one shot 25 is triggered when the electromagnet drive signal M (FIG. 4b) turns ON, and supplies a "1" output to one input terminal of the AND gate 24 for a certain period of time. This time is usually 2 times the period T of the printing position detection signal W [Fig. 4a].
It is set to ~3 times.

Therefore, after one shot 25 is turned on,
When both signals M and W are turned OFF at point P, the AND gate 23 becomes logic "1", the AND gate 24 also becomes logic "1", and the second one shot 26 is triggered. Like the first one shot 25, the time constant of this second one shot 26 is set to 2 to 3 times the period T of the type position detection signal W, and during this period, one input terminal of the AND gate 27 is A “1” output is provided. and,
When the type position detection signal is switched from OFF to ON at point Q in FIG.

The NOT gate 30 and the ant gate 31 are
This is a configuration for detecting the malfunction shown in FIG. 5, and after a certain period of time, the electromagnet drive signal M
Figure b] is used to detect the ON state.
That is, in FIG. 5, when the electromagnet drive signal [FIG. 5b] turns ON, the first one shot 2
Since the output of 5 is ON for a certain period of time, this output is
The signal is inverted via the NOT gate 30 and supplied to the AND gate 31, and in this state, the AND gate 31 is at logic "0". Then, when the first one shot 25 is reset after a certain period of time has elapsed, this output is inverted by the NOT gate 30 and becomes one input of the AND gate 31. An electromagnet drive signal [FIG. 5b] is supplied to the other input terminal of the AND gate 31, and therefore, after a certain period of time has elapsed, that is, after the time constant of the first one shot 25 has elapsed, the AND gate 31 becomes logic "1" and generates an output at the output terminal 29 through the OR gate 28, thus detecting the malfunction shown in FIG.

As described above, according to the present invention, by utilizing the characteristic of a stationary printing type printer, that is, the characteristic that the type wheel stops rotating during the printing operation, the type wheel is rotated at the time when the type wheel should be stopped. By detecting the behavior of the device, malfunctions can be easily detected with a simple circuit configuration.
In effect, the printer's type selection and printing operations can be controlled in a closed loop, and in particular, printers that use dry batteries can easily detect printing errors that can occur when the voltage drops, improving reliability. It has a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a type selection mechanism section of a static printing type printer according to the present invention;
The figure is a side view for explaining the positional relationship of the main parts of the printer in the first example, Figure 3 is a timing chart when the printer according to the present invention operates normally, and Figure 4 is a timing chart when the printer malfunctions. FIG. 5 is a timing chart when the printer makes another malfunction, and FIG. 6 is a block diagram of the malfunction detection circuit according to the present invention. DESCRIPTION OF SYMBOLS 1... Type wheel, 2... Rotating shaft, 3... Hammer, 4... Spring clutch, 5... DC motor, 6... Control lever, 9, 10... Coil spring, 11... Gear, 12... ...Latching plate, 13
. . . Actuation ratchet, 14 . . . Type position detection device [detection disc].

Claims (1)

[Claims] 1. A type carrier having a large number of type characters disposed around its periphery and held rotatably; a type position signal generator that generates a pulse corresponding to each type as the type carrier rotates; and a drive signal. and a type carrier stopping means for stopping the rotation of the type carrier, and after the type carrier is stopped by the type carrier stopping means, the desired type is printed on the paper. The printer has an input terminal for inputting pulses from the type position signal generator and driving pulses for an electromagnet that drives an actuator that controls rotation and stop of the type carrier;
After the drive signal is generated, the type carrier stopping means is driven for a period during which the type carrier should be stopped, and the type carrier stopping means is driven again from the time when the type position signal generator generates a pulse corresponding to a desired type. During the period until the type carrier starts rotating when the type carrier starts rotating, the pulse from the type position signal generator changes from the time when the driving pulse of the electromagnet is turned on.
When the drive pulse of the electromagnet is turned OFF, then turned OFF and then turned ON, or when the drive pulse of the electromagnet
It is equipped with a malfunction detection device characterized by having a gate circuit that determines that a malfunction has occurred in the character selection operation and generates an output signal when the circuit does not turn off after a certain period of time has elapsed after being turned on. printer.