JPS6037798B2 - How to detect disconnection of printing magnet coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for detecting disconnection of a printing magnet coil, in particular, a method for detecting a disconnection of a printing magnet coil, in particular, a method of supplying a printing signal input to a first transistor that excites the printing magnet coil after power is turned on and before printing starts. The present invention relates to a method for detecting disconnection of a printing magnet coil in a line printer, in which disconnection of the printing magnet coil is detected for each printing magnet coil for one line.

A disconnection of the printing magnet coil in a line printer printing device causes serious defects such as omitted characters in the printing result, and is one of the most serious failures in the printing device.

Therefore, disconnection of the printing magnet coil must be detected at an early stage. Conventional line printer printing devices do not have a means to inspect each printing magnet coil for one line for the presence or absence of disconnection after turning on the power of the printing device and before starting printing. Since a disconnection of the printing magnet coil to which the printing signal is input is detected only when no printing occurs despite the signal being input, a disconnection of the printing magnet coil may occur. There is a drawback that when printing is started, characters may be omitted due to the disconnection.

The present invention aims to solve the above-mentioned drawbacks,
After turning on the power and before starting printing, attach each printing magnet for one line.
The presence or absence of wire breakage in the coil is inspected without actually printing, and even in the line immediately after printing starts, the printing magnet
It is an object of the present invention to provide a method for detecting a disconnection of a coil in a line printer, which prevents the occurrence of omitted characters caused by a disconnection of a coil. Therefore, the method for detecting disconnection of a printing magnet coil according to the present invention includes a plurality of printing magnet coils for one line provided in parallel and a first transistor that excites each of the magnet coils. A second transistor configured to detect a change in the output of the first transistor is provided corresponding to the first transistor, and
A multiplexer is provided that sequentially switches and calls the output of each of the second transistors, and after the power is turned on and before printing starts, the input of the print signal is sent to each of the first transistors for one row provided in parallel. The present invention is characterized in that the multiplexers are sequentially switched in a state in which the magnet coil is disconnected, and disconnection of each magnet coil is detected based on the output signal of the multiplexer. This will be explained below with reference to the drawings. FIG. 1 shows the circuit configuration of an embodiment of a printing magnet coil disconnection detection circuit according to the present invention, and FIG. 2 shows the configuration of an embodiment of the present invention.

In FIG. 1, numeral 1 is a first transistor, 2 is a second transistor, 3 is a printing magnet coil, and 4 is a printing magnet coil.
6 to 6 represent resistance. At a certain timing, a voltage with a logic value of "1" is applied as a printing signal to the base of the first transistor that excites the printing magnet coil 3. The voltage causes a base current to flow through the first transistor 1, which in turn energizes the printing magnet coil 3.
Printing is done.

Also, at times other than the above-mentioned printing timing, the base of the first transistor 1 has a low logic value of "0".
An applied voltage of the level is being applied. Since the current flowing to the base of the first transistor 1 due to the low level applied voltage is very small, the excitation current, that is, the collector current that is sufficient to drive the printing magnet coil and print, does not flow. The collector of the transistor 1 of No. 1 has a voltage approximately equal to the voltage Vcc applied to the printing magnet coil 3. The divided voltage obtained by dividing the collector voltage Vcc of the first transistor 1 by the resistors 4 and 5 is applied to the base of the second transistor 2, and the divided voltage obtained by dividing the collector voltage Vcc of the first transistor 1 is applied to the base of the second transistor 2. The output of transistor 2 also changes as follows.

That is, {1} The logic value “
When a low level voltage of 0'' is applied, the first transistor 1 is in the off state, so the base current flows to the second transistor 2, and the second transistor 2 is in the on state. The output collector voltage is at a low level with a logic value of "0".

■ When a high-level voltage with a logical value of "1" is applied to the base of the first transistor 1, the first transistor 1 is in the on state, so the voltage outside the collector of the first transistor 1 is Since the potential is low, the base current does not flow through the second transistor 2, and the second transistor is turned off, and its output collector voltage is at the power supply voltage E, which is a high logic value of "1".・It is the level.

[3' Now, assuming that the printing magnet coil 3 is disconnected, the base of the second transistor 2 is at ground potential, and the second transistor 2 is in the off state, so its output The collector voltage of is at a high level with a logic value of "1" as in the above case (2).

As can be seen from {1), {2}, and {3}, the potential of the collector of the second transistor 2 reaches the /.i level when a logic value "1" is applied to the base of the first transistor 1. and when the printing magnet coil 3 is disconnected, and when a logic value "0" is applied to the base of the first transistor 1, the second transistor 2
The voltage at the collector of , changes to low level.

Therefore, it is possible to check whether or not there is a disconnection in the printing magnet coil 3 in a state where the logic value is "0" without inputting a print signal with the logic value "1" to the first transistor 1. That is, when the printing magnet coil 3 is disconnected, the collector potential of the second transistor 2 is at a high level, and when it is not disconnected, it is detected because it is at a low level. In the configuration of an embodiment according to the present invention shown in FIG. 2, numerals 1 and 6 correspond to those in FIG. 1, and 7-0 and 7-N are printing magnet coil disconnection detection circuits. 1 arranged in parallel
The number of printing hammers corresponding to the number of lines is provided, and the circuit configuration shown in Figure 1 is used, 8 is a multiplexer, 9 is a resistor, 10 is an eleven circuit, and 11 is an R
The memory device 12 to 15 is an AM storage device in which print information to be printed is stored, and AND circuits are shown, respectively.

When the printing apparatus is powered on, the contents of RAM II are cleared via the AND circuit 15, and the RAM I indicates a logical value of "0".

Therefore, when printing information of a certain line is read from the RAMI I, the printing magnet coil disconnection detection circuit 7-
The low level signal with the logic value "0" is input to each of the first transistors 1 of 0 and 7-N. For example, R
The printing magnet connected to the i-th AMII
Since the logic value "0" is also input to the first transistor 1 of the coil disconnection detection circuit 7-i, as explained above, the printing magnet/coil disconnection detection circuit 7
When the printing magnet coil 3 of -i is disconnected, the output of the second transistor 2 has a logical value of "1".
When a low-level signal appears and the printing magnet coil 3 is in a normal state, a low-level signal with a logic value of 0 appears at the output of the second transistor 2. A signal indicating the state is input to the i-th multiplexer 8. The above explanation is about the printing magnet/coil breakage detection circuit 7-i, but the same machine also applies to other printing magnet/coil breakage detection circuits, such as the printing in the printing magnet/coil breakage detection circuit 7-i. The disconnection detection signal of the printing magnet coil 3 is input to the 0th position of the multiplexer 8, and the printing magnet coil disconnection detection circuit 7-N'
The disconnection detection signal of the printing magnet coil 3 is inputted to the Nth multiplexer 8. On the other hand, after turning on the power and before starting printing,
When a start signal for testing whether there is a disconnection in the coil is input to the register 9, the register transmits the pulses sent from the 11th circuit 10 one by one, and the AND circuit 12 (at this time, the other inputs of the AND circuit 12 are The signal is input to the multiplexer 8 via the high level signal (input at high level when the power is turned on).

When the multiplexer 8 receives sequential pulses from the resistor 9, it sequentially inputs the input signals from the printing magnet coil disconnection detection circuits 7-0 and 7-N to the AND circuit 13. AND circuit 14 and register 9
Since the count pulse from the count pulse and the disconnection detection signal of the printing magnet coil from the printing magnet coil disconnection detection circuit corresponding to the count pulse are input in synchronization, for example, A disconnection detection signal "1" indicating that the printing magnet coil 3 is disconnected is sent from the i-th printing magnet coil disconnection detection circuit 7-i.
”, the AND circuit 14 has a logic value of “1”.
If it is normal, the AND circuit 14 outputs the logical value "
0" is output. In this way, the switching control circuit section that sequentially switches the output of the multi-breaker 8 allows the multi-
The outputs of the respective printing magnet coil disconnection detection circuits 7-0 to 7-N input to the plexer 8 are sequentially called,
The printing magnet coils 3 arranged in parallel for one line are inspected for breakage without actually printing, and if there is a breakage, the position of the broken printing magnet coil can be known. As explained above, according to the present invention, it is possible to detect the presence or absence of a disconnection in each printing magnet coil without printing before turning on the power and starting printing. It is possible to know its location when it is there.

Since printing can be performed without disconnection of the printing magnet coil, there will be no occurrence of omitted characters even in the line immediately after printing starts, and the reliability of the printing device can be improved.

[Brief explanation of the drawing]

FIG. 1 shows the circuit configuration of an embodiment of a printing magnet coil disconnection detection circuit according to the present invention, and FIG. 2 shows the configuration of an embodiment of the present invention. In the figure, 1 is a first transistor, 2 is a second transistor, 3 is a printing magnet coil, 4 to 6 are resistors, 7-0 is absent, 7-N is a printing magnet coil disconnection detection circuit, 8 is a multiplexer, 9 is a register, 1
0 represents 11 circuits, 11' represents RAM, 12 represents none, and 15 represents an asode circuit. Figure 1 Figure 2

Claims (1)

[Claims] 1. A plurality of printing magnetic coils for one line provided in parallel and a first transistor for exciting each of the magnetic coils, and configured to detect a change in the output of the first transistor. A plurality of second transistors are provided corresponding to the first transistor, and a multiplexer is provided to sequentially switch and call the output of each of the second transistors, and the plurality of second transistors are provided in parallel after power is turned on and before printing starts. The multiplexer is sequentially switched without inputting the print signal to each of the first transistors corresponding to one row, and the disconnection of each magnet coil is detected based on the output signal of the multiplexer. A method for detecting disconnection in a printing magnetic coil, characterized by the following.