JPS5818232B2 - Inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus equipped with a device for detecting the charged state of ink particles.

This type of inkjet recording apparatus has a configuration as shown in FIG.

That is, this recording device includes nozzles 5 that eject ink;
An electrostrictive element 4 that vibrates the nozzle 5, an oscillator 1 that drives the electrostrictive element 4, a recording signal generator 2 that generates an electric signal for charging, a charging electrode 6 that applies electric charge to the ink particles 7, and a a deflection electrode 8.8 for deflecting the ink particles 7; a power source 9 for the deflection electrode 8; a sensor 10 for detecting the amount of charge on the ink particles 1;
It is comprised of a charging state detection circuit 3 for amplifying the output from the sensor 10 and detecting whether the charging state is normal, a gutter 11 for collecting unnecessary inorganic particles 1, a recording medium 12, and the like.

Conventionally, a charging state detection circuit as shown in FIG. 2 has been used in this inkjet recording apparatus.

That is, the detection signal from the sensor 10 is sent to the sensor amplifier 2.
2, a band pass filter 23 extracts only the necessary signals, a voltage amplifier 24 amplifies the signals, and a smoothing circuit 25
After smoothing the signal, the output signal Vo was obtained.

This output signal V. As shown in FIG. 1, this is fed back to the charging electrode 6 via the recording signal generator 2 to control the amount of charge applied to the ink droplets 7.

When starting the inkjet recording apparatus or after replacing the nozzle due to clogging, etc., adjust the amplification degree of the voltage amplifier 24 of the charging state detection circuit with the gain adjustment volume 27.
The output of the voltage amplifier 24 must be adjusted to the appropriate output.

However, in the conventional charging state detection circuit, the voltage amplifier 24
There is no mechanism to determine whether the output is within the appropriate output range.

Therefore, when adjusting the gain adjustment volume 27,
Special measuring equipment 28 such as a synchroscope must be prepared for adjustment and confirmation, which is difficult to handle.

Furthermore, since the measuring device 28 such as a synchroscope can only make one-point comparisons, it is necessary to perform two operations in order to adjust and check whether the voltage amplifier is within the appropriate output range.
It is necessary to perform this process more than once, and the operation is time-consuming and complicated.

In addition, in the conventional charging state detection circuit, the bandpass filter 2
3, so its frequency adjustment volume is 26
Adjustment also requires a special measuring device 28 such as a synchroscope, making the adjustment work extremely complicated.

Phase matching is a very important operation in order to always perform distortion-free printing in an ink shared printing apparatus.

However, if the measuring device 28 is prepared and adjusted each time as described above, adjustment errors are likely to occur, which often results in poor recording.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording apparatus that eliminates the above-mentioned drawbacks of the prior art and is easy to adjust and reliable.

In order to achieve this object, the present invention applies an electric charge to ink particles ejected from a nozzle, and depending on the amount of electric charge, deflects the ink particles to adhere to a recording medium to perform recording. A sensor detects the amount of charge on the ink particles,
In an inkjet recording apparatus in which the detection signal is amplified by a voltage amplifier whose amplification degree is adjustable and the amount of charge given to the ink particles is controlled according to the output of the voltage amplifier, the output of the amplifier is the appropriate output of the amplifier. It is characterized by comprising a display device that displays whether or not it is within the range.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6.

FIG. 3 is a block circuit diagram of a charging state detection circuit according to an embodiment of the present invention.

The amount of charge on the ink particles is detected by a sensor 10, the detection signal is amplified by a sensor amplifier 22, and high frequency noise is separated by a low pass filter 30.

The output from the filter 30 is amplified by a voltage amplifier 24 equipped with a gain adjustment volume 27, and the output is amplified by a smoothing circuit 2.
Output signal V through 5.

As shown in FIG. 1, this is fed back to the charging electrode 6 via the recording signal generator 2 to control the amount of charge applied to the ink droplets 7.

38 is a display device that displays whether the output of the voltage amplifier 24 is within the appropriate output range of the amplifier 24, and is connected to the output side of the smoothing circuit 25.

The display device 38 includes a first comparator 31 , a second comparator 32 , a first display element 33 consisting of a light emitting element connected to the output side of the first comparator 31 , and a light emitting element connected to the output side of the second comparator 32 . It has a second display element 34 consisting of an element.

In this inkjet recording apparatus, if the appropriate output range of the voltage amplifier 24 for giving a normal amount of blue electricity to ink particles is, for example, 7.7 to 9.4V, the lower limit of the appropriate output range (7.7V) is The first reference value of the first comparator 31 is set as the upper limit value (9,4V) of the appropriate output range as the second reference value of the second comparator 32, and the resistors 35, 36, 3
7, 7 and 7V corresponding to the first reference value are applied to the first comparator 31, and 9 and 4V corresponding to the second reference value are applied to the second comparator 32, respectively, on the positive input side.

Output voltage V of voltage amplifier 24. is applied to the negative input sides of the first comparator 31 and the second comparator 32.

Therefore, the output voltage V of the voltage amplifier 24.

is below the lower limit of the appropriate output range of the voltage amplifier 24, the first comparator 31 and the second comparator 32
As a result, the first display element 33
Both the second display element 34 and the second display element 34 are in the off state.

Output voltage V of voltage amplifiers 2 and 4. If it is within the appropriate output range, the first comparator 31 and the second comparator 32 compare each other, and as a result, the first display element 33 is turned on and the second display element 32 is turned off.

Output voltage V of voltage amplifier 24.

is higher than the upper limit of the appropriate output range, the first comparator 31 and the second comparator 32 perform a comparison, and as a result, the first display element 33 and the second display element 3
4 are both in a lit state.

These display modes are summarized in FIG. 4. When both the first display element 33 and the second display element 34 are off, the output voltage V of the voltage amplifier 24.

In this case, it is necessary to turn the gain adjustment volume 27 of the voltage amplifier 24 to increase the amplification degree of the voltage amplifier 24 until only the first display element 33 lights up. be.

Note that the output voltage V of the voltage amplifier 24.

To check whether the output is within the appropriate output range, check the display element 3.
3. You can easily tell by looking at the 340 display mode.

When the first display element 33 is turned on and the second display element 34 is turned off, the output voltage V of the voltage amplifier 24.

is within the appropriate output range, indicating that the charged state of the ink particles is normal.

When both the first display element 33 and the second display element 34 are lit, the output power V of the voltage amplifier 24.

In this case, it is necessary to turn the gain adjustment volume 27 of the voltage amplifier 24 to lower the amplification degree of the voltage amplifier 24 until only the second display element 32 turns off. Yes, the operation can be performed while checking the display mode of the display elements 33 and 34.

FIG. 5 shows a modification of the display device, and the difference from the display device in FIG. 3 is that a voltage corresponding to the second reference value is applied to the negative input side of the second comparator 32, and the positive input side , the output voltage V of the voltage amplifier 24.

This is the point at stake. FIG. 6 shows the display mode of this display device. When the first display element 33 is off and the second display element 34 is on, the voltage amplifier 24
The output voltage V.

indicates that the output is lower than the appropriate output range.

When both the first display element 33 and the second display element 34 are lit, the output voltage V of the voltage amplifier 24.

is within the appropriate range.

When the first display element 33 is turned on and the second display element 34 is turned off, the output voltage V of the voltage amplifier 24.

is higher than the appropriate output range.

Therefore, if the output voltage Vo of the voltage amplifier 24 is within the appropriate output range, it can be adjusted and confirmed while looking at the display modes of the first display element 33 and the second display element 34.

In the above embodiment, a light emitting element is used as a display element, but other notification elements such as a buzzer or a bell can also be used, and the amplification degree of the voltage amplifier 24 can be automatically adjusted depending on the operation of the display device. It is also possible to adjust.

' If the low-pass filter 30 is used as in the embodiment shown in FIG. 3, adjustment of the frequency adjustment volume becomes unnecessary.

That is, conventionally, a bandpass filter equipped with a frequency adjustment volume was used, but since low-frequency noise is relatively smaller than high-frequency noise, there is no problem even if the low-pass filter 30 is used. Adjustment volume and its adjustment operation become unnecessary.

As explained above, the present invention includes a display device that displays whether or not the output of the voltage amplifier of the charging state detection circuit is within the appropriate output range of the amplifier. It is possible to immediately determine whether or not the presence of the voltage exists without preparing a measuring device, and to quickly and reliably adjust the amplification degree of the voltage amplifier and to confirm after the adjustment, thereby providing an inkjet recording device with good operability.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the configuration of an inkjet recording apparatus, FIG. 2 is a block circuit diagram of a conventional charging state detection circuit, FIG. 3 is a block circuit diagram of a charging state detection circuit according to an embodiment of the present invention, and FIG. 4 5 is a diagram showing the display mode of the display device used in the charging state detection circuit, and FIGS. 5 and 6 are circuit diagrams showing modifications of the display device and diagrams showing the display mode thereof. 5... Tuzzle, 7... Ink particles, 10
...Sensor, 12...Recorded object, 24
...Voltage amplifier, 31...First comparator, 32...Second comparator, 33...
. . . first display element, 34 . . . second display element, 38 . . . display device.

Claims (1)

[Claims] 1. Recording is performed by applying an electric charge to ink particles ejected from a nozzle, deflecting the ink particles according to the amount of electric charge, and making them adhere to a recording medium, and also using a sensor to detect the amount of electric charge of the ink particles. In an inkjet recording apparatus, the detection signal is amplified by a voltage amplifier whose amplification degree is adjustable, and the amount of charge given to the ink particles is controlled according to the output of the voltage amplifier. An inkjet recording device characterized by comprising a display device that displays whether or not the output is within an appropriate output range of an amplifier. 2. In claim 1, the display device comprises:
The first reference value is the lower limit of the amplifier's proper output range.
The comparator and the upper limit of the amplifier's proper output range are set to the second
A second comparator that is connected to the first comparator and changes the display mode when the output of the amplifier passes the first reference value, and a first display element that is connected to the second comparator and uses the output of the amplifier as the second reference. An inkjet recording device comprising: a second display element whose display mode changes when a value is passed.