JPS5812875B2 - Serial printer hammer cut device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial printer, and more particularly to a device for cutting the printer's hammer action when the current position of the print head during printing differs from a designated character position.

Serial printers, which are used as output devices for electronic computers, use a carrier to space a type wheel with multiple types at a predetermined printing position, then rotate the type wheel to select the type to be printed. The desired type is printed by striking the type with a hammer against the printing paper on the platen.

If an erroneous character is printed, the type wheel is returned to the home position before the next character selection operation to prevent erroneous printing of subsequent characters.

Conventionally, the control mechanism for selecting type has a current position counter 1, a subtracter 2, a counter 3, as shown in FIG.
, digital-to-analog converter (hereinafter abbreviated as "D/A converter") 4, flip-flop circuit 5, servo amplifier 6,
A servo motor 7, a type wheel 8 rotated by the servo motor 7, and a type wheel 8 rotated by the rotation of the type wheel 8.
a transducer 9 that generates a home position signal 91, a rotational speed signal 92, a position signal 93, and a position pulse 94; a gate circuit 10 that detects a position pulse generated after the current position of the type wheel 8 coincides with a designated character position; and a flip-flop circuit 11 that stores the pulses that have passed through the gate circuit 10.

An input terminal 21 of the subtracter 2 is given a digital position designation signal corresponding to a designated print position on the print wheel 8.

Now, if we apply a specified print position signal corresponding to the print character to the input terminal 21 and also add the output of the current print position counter 1 to the other input terminal 22, both output terminals of the subtracter 2 A signal deviation signal appears.

This output signal sets the flip-flop circuit 5, and a deviation signal, that is, the position difference between the current print position and the print character to be printed, is set in the counter 3. The D/A converter 4 converts the voltage into an analog voltage, and the differential voltage between this analog voltage and the rotational speed signal 92 of the type wheel 8 detected by the transducer 9 drives the servo motor 7 to rotate the type wheel 8.

As the servo motor 7 rotates, the transducer 9 also rotates, and a position pulse 94 is output at a rate of one every time the type position moves one position, sequentially changing the current position counter 1 in the direction of rotation of the type wheel 8. The counter 3 is counted up or down accordingly.

When the type wheel 8 rotates and reaches the designated position, the current position counter 1 indicates the count value of the next type position to be printed, the count value of the counter 3 becomes zero, and the flip-flop circuit 5 is reset with the zero signal. do.

This reset causes the contact 12' of the switch 12 to
to b, and the type position signal 93 becomes O(V).
The servo motor 7 stops at this position.

On the other hand, the gate circuit 10 has one input terminal 10b connected to the output side of the flip-flop circuit 5, and its gate is closed while the flip-flop circuit 5 is set.

However, when the output of the counter 3 becomes zero and the flip-flop circuit 5 is reset, the gate circuit 1'0 is opened, and after the current position of the type wheel 8 and the specified type position match, the type is Position pulse 9 generated when wheel 8 overruns
4, the pulse 94 appears at the output of the gate circuit 10.

Then, at the start of printing, the reset flip-flop circuit 11 is set and its output is inverted to serve as a home position return signal for returning the type wheel 8 to the home position.

When this home position return signal is generated, the type wheel 8 is returned to the home position prior to the next type selection, and the calculation content of the current position counter 1 is returned to the value (usually zero) corresponding to the home position. ,
After clearing the contents of the counter 3, the above-described character selection operation is repeated in response to a new specified character position signal to print.

The above configuration is similar to that proposed by the inventor of the present invention in Japanese Patent Application Laid-open No. 5
This invention is the same as the invention disclosed in Publication No. 1-58831.

In the conventional print check system configured as described above, if, for example, the second character is incorrectly printed as "0223" when it should be correctly printed as "0123", the third character will be transliterated correctly, Is it possible to keep printing errors to a minimum?It is difficult to tell which characters are due to printing errors just by looking at the printing results, and it is difficult to recognize that the printing is correct, giving incorrect information. become.

On the other hand, as described in Japanese Patent Application Laid-open No. 50-149418,
In low-speed printing devices, it has been proposed to lock the printing wheel, detect the lock position at that time, compare it with the printing signal, and if there is a discrepancy, generate an alarm or prevent the hammer from operating. ing.

However, this configuration may be possible with low-speed printing devices that print with a locked printing wheel.
In a high-speed printing device, which is the object of the present invention, in which the hammer operation must be interrupted after the hammer starts operating, it is impossible to reliably prevent printing.

The present invention aims to solve such problems in high-speed printing devices.According to the present invention, when the current position of the type wheel at the time of printing is different from the designated type position, This is detected and the hammer operation is cut off before the printing operation is completed to leave the character section blank, so that it can be determined later that it is incorrect printing.

Furthermore, it is also possible to cut the spacing of the carrier along with the hammer cut, re-execute the specified type selection operation, print correctly in the blank area, and immediately and automatically correct printing errors. .

The present invention has a configuration in which the conventional device described above is combined with the following device.

That is, a gate circuit 13 is further provided, one input terminal 13a of which is connected to the output terminal Q of the flip-flop circuit 11, and the other input terminal 13b inputted with a hammer designation pulse which becomes a hammer drive signal during normal printing. do.

The output of the gate circuit 13 becomes a hammer drive signal,
Hammer magnet 15 via magnet driver 14
control.

Generally, to increase printing speed, a hammer drive signal is applied already while the type wheel is rotating to start the hammer operation.

FIG. 2 shows a position signal 93 and a position pulse 94.
, the relationship between the Q output of the flip-flop circuit 5, the hammer drive signal, and the hammer operation of the type wheel.

In the figure, the solid line indicates normal conditions, and if overrun occurs due to load fluctuations, inertia of the type wheel, etc.
This will be shown by the broken line.

That is, T. which is the normal stopping position of the type wheel. At this point, the flip-flop circuit 5 has been reset and the gate circuit 10 is open.

Therefore, the position pulse P after rising is the gate circuit 1
0, setting the flip-flop circuit 11 which had been reset, and inverting its output.

Therefore, the output terminal Q of the flip-flop circuit 11, which had maintained the logic H and opened the gate circuit 13, becomes valid at that point, closes the gate circuit 13, and cuts off the hammer drive signal.

Therefore, the hammer, which was in the middle of its operation, returns to its original position before hitting the printing paper on the platen 20, as shown by the broken line, and no printing is performed.

As described above, according to the device of the present invention, the gate circuit is closed by the home position return signal generated when the type wheel malfunctions, the bantamer drive signal passing through the gate circuit is cut off, and the hammer is turned off before printing is completed. Since the printing error is restored and the erroneous portion is made bright white, it is possible to easily determine that a printing error has occurred, and the provision of erroneous information can be prevented.

Furthermore, there is no risk that the type wheel will be damaged by being struck by a hammer during rotation due to malfunction.

Furthermore, the present invention includes a space cutting device illustrated in FIG. 3, which cuts the spacing of the printing head carrier during hammer cutting, and automatically prints correctly in the blank area.
As a result, the configuration is such that correct printing without mistakes is possible.

In the space cut circuit, 16 is a gate circuit that controls the space destination designation signal, and one input terminal 16 of the gate circuit controls the space destination designation signal.
The output of the flip-flop circuit 11 in FIG. 1, ie, the home position return signal, is applied to the terminal a, and the space destination designation signal is applied to the other input terminal 16b.

A destination position counter 17 indicates the position to which the carrier should move, and a current position counter 18 counts position pulses generated by the movement of the carrier to determine the current position.

The output of these two counters 17 and 1B is the subtracter 19.
The difference signal between the two appears as an output and becomes a space control signal.

This space control signal causes the subtraction circuit 2 shown in FIG.
The same configuration as described below is used to drive the leather roller movement and the two-wheel motor, but during normal operation, the flip-flop circuit 1
1 is reset, its output is logic H, and gate circuit 16 is open.

However, once the flip-flop circuit 11 is set, its output becomes a logic low and the gate 16 is closed.
The reception of new space destination signals is prohibited and the carrier stops at the same location.

Therefore, the type wheel is returned to its home position by the home position return signal, and the hammer cutting device according to the invention also works to create a blank space, so if the same specified type selection is executed again and printing is performed, the error will be corrected. is printed.

As described above, according to the present invention, if the current position of the type wheel during printing differs from the designated type position, the hammer operation is interrupted and the printing location is left blank, so that printing errors can be avoided. It can be easily identified and caution can be called for.

In addition, if you also perform a space cut in conjunction with this hammer cut function to stop the movement of the carrier, select the designated type again, and print, it is possible to provide correct information without printing errors as a result. Processing reliability is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a combination of a conventional print checking device and a hammer cutting device according to the present invention, and FIG. 2 is a timing chart showing the relationship among position signals, position pulses, Q outputs of storage elements, hammer drive signals, and hammer operations. , FIG. 3 is a block diagram of a space cut circuit for printing correction. In the figure, 8 is a print head, 9 is a transducer,
14 is a magnetic driver, 15 is a hammer magnet,
13 represents a (NAND) gate circuit, and 16 represents a (NAND) gate circuit.

Claims (1)

[Claims] 1. A transducer is provided which generates a position pulse for each one type pitch rotation of the type wheel and generates a home position signal at the home position of the type wheel, and the type wheel changes depending on the deviation between the current position of the type wheel and the specified type position. and a memory element for storing a position pulse after the drive motor of the transducer is operated to select a type character and the current position of the type wheel matches the designated character position, and when the memory element is set, the next character is selected. In a printer in which the type wheel returns to the home position prior to the type selection operation, the output signal of the memory element and the hammer drive signal are input,
A serial printer characterized in that a NAND circuit is provided for supplying the output to a hammer drive circuit, and when the memory element is set during designated character selection operation, the hammer operation is interrupted by the output signal of the NAND gate circuit. hammer cutting device.