JPS6189859A - Space control signal formation circuit - Google Patents

Abstract

PURPOSE:To prevent the print slippage and the generation of error by fixing the gain of an amplifier to the value till then during stoppage of space motor, by a method wherein the control circuit which controls the gain of amplifier according to the change of analogue signal, the comparator which extracts the control operating conditions of control circuit from the output of amplifier and the means by which the output of comparator is fixed during the standstill of space motor and made free during operation, are provided. CONSTITUTION:When the output SL1 of operational amplifier 6 is '1' and the output SL2 of operational amplifier 7 is '0', the gain of operational amplifier 5 is not changed. When a space motor 2 comes to standstill, '1' is put into SL1 of variable resistance setting circuit 8 via an OR circuit 10. Because the output of NOT circuit 12 is '0', the output of AND circuit 11 becomes '0' and the SL2 of variable resistance setting circuit 8 becomes '0'. A slit disc plate 1 is rotated by impact or the like during standstill of space motor 2, and the operational amplifier 5 is amplified by the generation of microanalogue signal. However the outputs of operational amplifiers 6 and 7 may be changed, the logical levels of SL1 and SL2 of variable resistance setting circuit 8 are fixed and the gain of operation amplifier 5 is not changed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a serial printer, and in particular, an abnormal signal based on a malfunction of a slit disk plate that detects the rotational state of a space motor that is the source of creating a space control signal.
The present invention relates to a space control signal generation circuit that prevents mistakes in space control.

In a serial printer, a space motor is driven to move a carriage that positions a print head at a print position to print characters, etc.

Then, when the printing of - lines is completed, a new line operation is performed.

In order to perform this spacing operation, some printers use dot signals to detect the timing of printing start and stop, and zone signals to manage printing digits.

These dot signals and zone signals are created by reading the slits in a slit disk plate attached to the space motor shaft with an optical sensor, converting it into an electrical signal, amplifying it, and detecting it based on the slice level.

Since this amplified electrical signal always requires a constant voltage value, it is controlled by an automatic gain adjustment control circuit.

Since this automatic gain adjustment control circuit controls the gain of the amplifier based on the electrical signal, it operates even when an abnormal signal is generated due to a malfunction of the slit disk plate.

Since the gain of an amplifier adjusted by an abnormal signal is often different from the gain adjusted by a normal signal, it is necessary to prevent space control from becoming abnormal.

[Conventional technology]

FIG. 2 shows an example of a conventional space control signal generation circuit.

The slit disk plate 1 is attached to the rotating shaft of a space motor 2 and is illuminated by a light emitting element 3.

Therefore, as the space motor 2 rotates, the slit disk plate 1 also rotates, and the light from the light emitting element 3 is applied to the light receiving element 4 through the slit.

The light receiving element 4 generates an analog signal by intermittently turning on and off the voltage from the power source E using the light from the light emitting element 3 which is intermittently applied through the slit of the slit disk plate 1, and supplies the analog signal to the operational amplifier 5. Operational amplifier 5 amplifies this analog signal and sends it to operational amplifiers 6 and 7.

FIG. 3 is a diagram explaining the operation of operational amplifiers 6 and 7.
The figure is a diagram explaining the conditions.

As shown by the solid line d, from the analog signal amplified by the operational amplifier 5 as described above, a waveform with a small amplitude is obtained from the small slit of the slit disk plate 1, and a waveform with a large amplitude is obtained from the large slit. Then, a dot signal is created from the small waveform and a zone signal is created from the large waveform by a circuit (not shown).

The operational amplifier 6 has a comparison voltage indicated by vl, and the operational amplifier 7
A comparison voltage indicated by v2 is applied to each of the terminals. Here, as shown in FIG. 4, the output SLI of the operational amplifier 6 becomes "0" when the signal level of the small waveform is equal to or higher than the comparison voltage V1, as indicated by the dotted line a, and the output SL2 of the operational amplifier 7 becomes "0". As shown in FIG. 4, the signal level of the small waveform becomes "0" when its peak value is equal to or higher than the comparison voltage 72, as indicated by the dotted line a.

Further, as shown in FIG. 4, the output SL1 of the operational amplifier 6 becomes "l" when the signal level of the small waveform is less than the comparison voltage Vl, as shown by the solid line d, and the output SL2 of the operational amplifier 7 becomes "1". As shown in FIG. 4, the signal level of the small waveform becomes "0" when its peak value is equal to or higher than the comparison voltage 72, as shown by the actual Fv% d.

Furthermore, as shown in FIG. 4, the output SL, 1 of the operational amplifier 6 becomes "1" when the signal level of the small waveform is less than the comparison voltage V1', as shown by the dotted line.
As shown in FIG. 4, the output SL2 of the operational amplifier 7 becomes "1" when the signal level of the small waveform has a peak value below the comparison voltage V2, as shown by the dotted line.

The variable resistance setting circuit 8 switches the resistance value of the variable resistance 9 to lower the gain of the operational amplifier 5 when both SLI and SL2 are "O". Further, when SLI is "1" and SL2 is "0", the resistance value of the variable resistor 9 is not changed and the gain of the operational amplifier 5 is not changed. Further, when both SLI and SL2 are "1", the resistance value of the variable resistor 9 is changed to increase the gain of the operational amplifier 5.

The above operation stops when a zone signal is detected.

Therefore, the gain of operational amplifier 5 is controlled to always perform proper amplification.

[Problem that the invention seeks to solve]

Since the operation is as described above, the slit disk plate 1 does not move while the space motor 2 is stopped, so that the slit disk plate 1 shown in FIG.
, b, d should not be generated, but
When a shock is applied to a serial printer, an external force is applied to the space movement mechanism, and the slit disk plate 1 vibrates and rotates. As the slit moves, an analog signal is generated in the light receiving element 4, and an analog signal is generated by the operational amplifier 5. It is amplified and enters the operational amplifier 6.7.

Since this analog signal is smaller than the regular analog signal, the variable resistance setting circuit 8 switches the variable resistance 9 to make the gain of the operational amplifier 5 abnormally large.

Therefore, when the space motor 2 is activated and starts space operation, it may misjudge the dot signal as a zone signal and cause printing misalignment, or it may misjudge that the print head has been moved by an external force while stopped, causing an error. There are problems such as the occurrence of

[Means for solving problems]

The above problem is caused by a control circuit that controls the gain of an amplifier that amplifies an analog signal from a light-receiving element in response to a change in the analog signal, and a control circuit that controls the gain of an amplifier that amplifies an analog signal from a light-receiving element in a circuit for creating a space opening signal for a serial printer. A comparison circuit for extracting operating conditions from the output of the amplifier, and means for fixing the output of the comparison circuit while the space motor is stopped and freeing it while the space motor is in operation are provided. The problem is solved by fixing the gain of the amplifier by preventing any control action.

[Effect]

In other words, the space motor is designed to prevent the gain of the amplifier, which is the basis for creating dot and zone signals, from being set to an incorrect value due to an erroneous signal generated by the vibration of the slit disk plate while the space motor is stopped. While the system is stopped, the gain of the amplifier is fixed at the previous value.

〔Example〕

FIG. 1 is a block diagram of a circuit showing one embodiment of the present invention.

Figure 1 shows an OR circuit 10 and an AND circuit 11 in the circuit of Figure 2.
and a NOT circuit 12 are added.

"1" is sent from the processor that controls the operation of the serial printer via the terminal CPU when the space motor 2 is not being driven, and "0" is sent when the space motor 2 is being driven.

Therefore, when the space motor 2 is stopped, the OR circuit 10
After that, "l" is input to SLI of the variable resistance setting circuit 8. Further, since the output of the N07 circuit 12 is "O", the output of the AND circuit 11 becomes "0" regardless of the output of the operational amplifier 7, and SL2 of the variable resistance setting circuit 8 becomes "0".

Therefore, as mentioned above, when the slit disk plate 1 rotates due to an impact while the space motor 2 is stopped, a minute analog signal is generated, which is amplified by the operational amplifier 5, and how the outputs of the operational amplifiers 6 and 7 change. Also, SL of variable resistance setting circuit 8
The logic levels of I and SL2 are fixed. Therefore, since the resistance value of the variable resistor 9 remains unchanged, the gain of the operational amplifier 5 does not vary.

When O'' is input to the terminal CPU due to the start of space control, N
The output of the OT circuit 12 becomes "1".

Therefore, the operational amplifiers 6 and 7 are connected to the SL as explained in FIG.
I and SL2 can be controlled respectively.

〔Effect of the invention〕

As described above, the present invention can prevent printing misalignment and errors even if the slit disk plate malfunctions while the space motor is stopped due to vibration or the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a conventional space control signal generation circuit, and FIG. 3 is a diagram explaining the operation of operational amplifiers 6 and 7. FIG. 4 is a diagram illustrating the operating conditions of operational amplifiers 6 and 7. In the figure, 1 is a slit disk plate, 2 is a space motor, 3 is a light emitting element, 4 is a light receiving element, 5, 6, 7 is an operational amplifier, 8 is a variable resistance setting circuit, 9 is a variable resistor,
10 is an OR circuit, 11 is an AND circuit, and 12 is an N07 circuit.

Claims (1)

[Claims] A space control signal generation circuit for a serial printer includes a control circuit that controls the gain of an amplifier that amplifies an analog signal from a light-receiving element according to a change in the analog signal, and a control circuit that controls the control operating conditions of the control circuit for the amplifier. A comparison circuit for extracting data from the output, and a means for fixing the output of the comparison circuit when the space motor is stopped and freeing it while the space motor is in operation are provided,
A space control signal generation circuit characterized in that while the space motor is stopped, new control operations of the control circuit are blocked and the gain of the amplifier is fixed.