JPH08258256A - Recording apparatus - Google Patents

Abstract

PURPOSE: To well transmit data from a control circuit to a drive circuit by providing the drive circuit applying an electric signal to piezoelectric elements and the control circuit transmitting recording data to the drive circuit during the application of the signal excepting the transient region of the signal. CONSTITUTION: A recording apparatus avoids the time zone of the rising time Td and falling time Te of a drive signal and divides DATA 3 corresponding to 32 bits into two data to transmit the same. That is, DATA 3 corresponding to 16 bits stored in a latch is transmitted in the time zone of a transmission time Tb and DATA 3 corresponding to 16 bits stored in a latch is transmitted in the time zone of a transmition time C. By this constitution, nozzles N1, N2, N3 are not superposed on CLK 2 and the synchronism of CLK 2 and DATA 30 is not collapsed. Therefore, the circuit on and after a shift register is not different from the data desired by a control circuit 20 to drive a head 23 normally and a high-grade image can be obtained without damaging image quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device for deforming a piezoelectric element by applying an electric signal to the piezoelectric element and recording characters or figures by the deformation.

[0002]

2. Description of the Related Art Conventionally, an ink jet type print head of an ink jet recording apparatus has a main structure shown in FIG. FIG. 4A is a cross-sectional view in the flow path direction.
4B is a diagram showing a part of a cross section taken along the line AA of FIG.

Ink in an ink supply source (not shown) is filled into an ink chamber 56 defined by a partition wall 54 formed of a piezoelectric element through an ink supply port 51 formed in a cover plate 50 and a manifold 53. . Nozzle holes 58, which serve as ejection holes for the ink 52, are provided in the nozzle plate 57 at the ends of the ink chambers 56. As shown in FIG. 4B, the partition walls 54 have drive electrodes 59 a, 5 a and 5 b.
9b and the ground electrode 60 are provided. The drive electrodes 59a and 59b and the ground electrode 60 are electrically connected to the electrode lead-out port 61, and an electric signal is supplied from a drive circuit not shown in FIG. An electric signal, which is an ink ejection signal, is supplied from the drive circuit to the drive electrodes 59a and 59b, and the ground electrode 60 is connected to the ground, whereby partition walls 54a and 54b formed of piezoelectric elements are formed.
Is deformed, and ink ejection energy for ejecting ink is generated in the ink 52 in the ink chamber 56b. Then, the ink 52 flies as an ink droplet from the nozzle hole 58,
Adhere to recording paper.

As described above, in the recording apparatus having the ink jet type print head, the partition walls 54a, 5a of the piezoelectric element are formed.
An electrical signal is applied between the drive electrodes 59a and 59b facing each other and the ground electrode 60, which causes the piezoelectric element to mechanically deform and generate energy in the ink 52 in the ink chamber 56b to generate a nozzle hole. Ink droplets are ejected from 58. Here, from the viewpoint of the drive circuit, the space between the drive electrodes 59a and 59b provided on the piezoelectric element and the ground electrode 60 can be regarded as a capacitive load. Therefore, in order to increase the potential difference between the opposing drive electrodes 59a and 59b provided on the piezoelectric element and the ground electrode 60, a charge current for charging the charge from the drive circuit is required. Further, in order to eliminate the potential difference, it is necessary to flow a discharge current for discharging the electric charge between the drive electrodes 59a and 59b and the ground electrode 60.

FIG. 5 is a diagram showing the internal structure of a drive circuit for driving the above-mentioned ink jet print head.
FIG. 5 shows the case of a 32-channel multi-nozzle head. The shift register 61 is supplied with a clock signal CLK62 from an ink ejection data generation circuit (not shown) and an ejection data signal DATA63 which is serially transferred in synchronization with the CLK62. Is converted into a parallel signal by the shift register 61 and output to the latch 64. The latch 64 converts the input parallel signal to STB6 which is a latch command signal.
It is stored by 5 and output to the AND gate 66. AND
The gate 66 performs a logical product of the input output signal of the latch 64 and the ENA 67 which is an enable signal. The output of the AND gate 66 is input to the output circuit 68, and the input signal is converted by the output circuit 68 into a voltage and current suitable for the ink jet print head and output as a drive signal.

In FIG. 5, the following operation is performed in order to drive the electrostatic capacitance formed by the counter electrode provided on the piezoelectric element. To increase the potential difference between the drive electrodes 59a and 59b and the ground electrode 60, the print signal output from the AND gate 66 becomes "H", and the transistor 69 is turned on.
Is "ON" and the transistor 70 is "OFF", a charging current flows and the potential difference increases. In order to eliminate the potential difference between the drive electrodes 59a and 59b and the ground electrode 60, the print signal output from the AND gate 66 is
When it becomes “L”, the transistor 69 is “OFF”, and the transistor 70 is “ON”, a discharge current for discharging electric charge flows, and the potential becomes 0V.

FIG. 6 is a schematic diagram of an electric circuit of a serial printer using the ink jet type print head described in FIG. 4 and the drive circuit described in FIG. DATA 63, which is the ejection data signal, is transferred from the control circuit 71 to the drive circuit 75 mounted on the drive circuit board 73 by the harness cable 72. Then, the above-mentioned drive electrode 59a,
A current for charging / discharging the electrostatic capacitance formed between 59b and the ground electrode 60 flows through a route of drive power supply line 74 → drive circuit 75 → head 76 → head ground line 77 → ground line 78 during charging. Further, at the time of discharging, the current flows through a route of head 76 → driving circuit 75 → head ground line 77.

[0008]

However, in the recording apparatus of the conventional example as described above, the head ground line 77 is applied to the head ground line 77 when the drive signal 78 rises and falls (transient) like the current 79 shown in FIG. A current with a sharp peak flows. For example, when 32 channels are driven simultaneously, a peak charging current of Ipc per drive signal flows, and a large current of 32 × Ipc flows through the head ground line 77, although it is instantaneous. Therefore, noises N1 and N2 as shown by noise 80 in FIG. 7 occur in the head ground line 77 inside the drive circuit board 73.

Further, like the current 81 shown in FIG. 7, a current having a steep peak at the rising edge (transition time) of the drive signal 78 also flows through the ground line 78. For example, 3
When 2 channels are driven simultaneously, Ipe per drive signal
And a large current of 32 × Ipe instantaneously flows through the ground line 78. Therefore, the ground line 7 in the harness cable 72
8, noise N3 as shown by noise 82 in FIG. 7 is generated.

The noises N1, N2 and N3 are CL
If it is superimposed on K62, the synchronization between CLK62 and DATA63 will be lost, and the shift register 61 in the drive circuit 75 will malfunction. Therefore, the circuits after the shift register 61 are also affected by the malfunction of the shift register 61, and the head 76 is driven in a state different from the data desired by the control circuit 71, resulting in the deterioration of image quality. there were.

In order to solve the above-mentioned problems, as shown in Japanese Unexamined Patent Publication No. 6-191023, FIG.
At the invalid time T3 of the drive signal 78 shown in FIG.
A method in which the noises N1, N2, and N3 generated by 81 do not affect the drive circuit 75 is also considered. But,
If the ratio of the effective time T2 to the period T1 of the drive signal 78 is high, the invalid time T3 that can be spent for the transfer of DATA91 is short, and it is necessary to raise the frequency of DATA91 and CLK90. There was a problem that the cost was high.

The present invention has been made to solve the above-mentioned problems of the conventional method, and an object of the present invention is to provide a recording apparatus which favorably transfers data from a control circuit to a drive circuit. To do.

[0013]

In order to achieve this object, according to claim 1 of the present invention, an electric signal is applied to the piezoelectric element to deform the piezoelectric element, and the deformation records a character or a figure. In the recording apparatus, a drive circuit for applying the electric signal to the piezoelectric element, and a control circuit for excluding the transient region of the electric signal and transferring the print data to the drive circuit while the electric signal is being applied It has and.

According to a second aspect of the present invention, the control circuit transfers the recording data to the drive circuit even when the electric signal is not applied.

According to a third aspect of the present invention, the volume of the ink chamber filled with the ink is deformed by the deformation of the piezoelectric element, and the ink is ejected from the ink chamber.

[0016]

In the recording apparatus of the present invention having the above-mentioned structure, the drive circuit applies the electric signal to the piezoelectric element, and the control circuit removes the transient range of the electric signal and applies the electric signal. By transferring the recording data to the drive circuit during the period, the adverse effect on the data transfer due to the noise generated by the current flowing in the transient region of the electric signal is prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. However, the same members as those in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 is a diagram showing an internal structure of a drive circuit for driving an ink jet print head as described in FIG. 4 of the conventional example. FIG. 1 shows the case of a 32-channel multi-nozzle head.

The 16-bit shift register 1 has
The clock signal CLK2 from the ink ejection data generation circuit included in the control circuit 20 shown in FIG.
The injection data signal DATA3 that is serially transferred in synchronization with K2 is input, and the input DATA3 is converted into a parallel signal by the shift register 1 and output to the multiplexer 4.

The multiplexer 4 outputs the input parallel signal to either the latch a6 or the latch b7 selected by the SEL5 output from the control circuit 20. When SEL5 is at the logic level "L", the output of the multiplexer 4 is output to the latch a6. Also, SE
When L5 is at the logic level "H", the multiplexer 4
Is output to the latch b7.

The latch a6 stores the input output signal state of the multiplexer 4 by the STBa8 which is a latch command signal, and outputs it to the AND gate 9. The latch b7 stores the input output signal state of the multiplexer 4 by the STBb10 which is a latch command signal.
Output to D gate 9.

The AND gate 9 receives the input latch a6.
And the output signal of the latch b7 and the enable signal E
Performs a logical product with NA11. When ENA 11 is at the logic level "L", the output of the AND gate 9 is in the prohibited state regardless of the output states of the latches a6 and b7. When ENA11 is at the logic level "H",
The AND gate 9 outputs according to the output states of the latches a6 and b7.

The output of the AND gate 9 is input to the output circuit 12, and the input signal is converted into a voltage and current suitable for the ink jet print head 23 by the output circuit 12 and output as a drive signal. As described in the conventional example, the following operation is performed in order to drive the capacitance formed by the counter electrode provided on the piezoelectric element. In order to increase the potential difference between the electrodes of the formed capacitance, the print signal which is the output of the AND gate 9 becomes "H", the transistor 13 becomes "ON", and the transistor 14 becomes "OFF", so that charging is performed. A current flows, increasing the potential difference. Further, in order to eliminate the potential difference between the electrodes, the print signal output from the AND gate 9 becomes "L", and the transistor 13 turns "".
When the transistor is turned “OFF” and the transistor 14 is turned “ON”, a discharge current for discharging electric charges flows to set the potential to 0V.

FIG. 2 is a schematic diagram of an electric circuit of a serial printer using the ink jet type print head described in FIG. 4 and the drive circuit described in FIG. 1 of the conventional example. DATA3, which is the ejection data signal, is transferred from the control circuit 20 to the drive circuit 21 mounted on the drive circuit board 22 on the carriage (not shown) by the harness cable 27. Then, the current for charging and discharging the electrostatic capacitance formed between the drive electrode 59 and the ground electrode 60 in FIG. 4 of the conventional example is
At the time of charging, the electric current flows through a route of the driving power supply line 25 → driving circuit 21 → head 23 → head ground line 24 → ground line 26. Further, at the time of discharging, the current flows through a route of head 23 → driving circuit 21 → head ground line 24.

FIG. 3 is a timing chart of this embodiment.
The cycle Ta is the repetition cycle of the drive signal 30. The rising time Td is the time required for the drive signal 30 to change from ineffective to effective. The fall time Te is the time required for the drive signal 30 to change from valid to invalid. The transfer time Tb is a time during which the drive signal 30 is valid, and 16 bits of DATA3 transferred in 32 bits per cycle Ta are transferred during this transfer time Tb and stored in the latch a6. When the transfer of 16 bits is completed, 16 bits of DATA3 are stored in the shift register 1.
Are stored and converted into parallel signals. The output of the shift register 1 is a preset multiplexer 4
Is input to the latch a6 by SEL5. STBa8
Is a latch command signal for storing the signal input to the latch a6.

The transfer time Tc is a time during which the drive signal 30 is invalid, and the transfer time Tc is 32b per cycle Ta.
The remaining 16 bits of DATA3 transferred by it are transferred and stored in the latch b7. When the transfer of 16 bits is completed, 16 bits of DATA3 are stored in the shift register 1 and converted into parallel signals. The output of the shift register 1 is input to the latch b7 by the preset SEL5 of the multiplexer 4.
STBb10 is a latch command signal for storing the signal input to the latch b7.

The electric signal in the claims corresponds to the drive signal 30, and the transient range corresponds to the rising time Td and the falling time Te.

The control circuit 20 controls the CL to avoid the time zones of the rising time Td and the falling time Te in the cycle Ta.
K2, DATA3, STBa8, STBb10 are sent to the drive circuit 21.

In the recording apparatus as described above, like the current 31 shown in FIG. 3, a current having a sharp peak flows through the head ground line 24 when the drive signal 30 rises and falls (during transition). For example, when 32 channels are driven simultaneously, a peak charging current of Ipc per drive signal flows,
A large current of 32 × Ipc flows through the head ground line 24, although it is instantaneous. Therefore, noises N1 and N2 as shown by noise 32 in FIG. 3 are generated in the head ground line 24 inside the drive circuit board 22.

Further, a current having a steep peak at the rising edge (transition time) of the drive signal 30 flows through the ground line 26 like the current 33 shown in FIG. For example, 32
When the channels are driven simultaneously, a peak charging current of Ipe per drive signal flows, and a large current of 32 × Ipe flows through the ground line 26, although it is instantaneous. Therefore, the ground line 26 in the harness cable 27
Noise N3 as shown by the noise 34 in FIG.

However, according to the present invention, the data 3 of 32 bits is divided into two and transferred while avoiding the time zones of the rising time Td and the falling time Te of the drive signal 30.
That is, 16-bit DATA3 stored in the latch a6 is transferred during the transfer time Tb, and 16-bit DATA stored in the latch b7 is transferred during the transfer time Tc.
Transfer 3. As a result, noises N1, N2, N
3 and CLK2 and DATA without superimposing on CLK2
The synchronization of 30 will not be lost. Therefore, the circuits subsequent to the shift register 1 can drive the head 23 normally without being different from the data desired by the control circuit 20, and can obtain a high-quality image without impairing the image quality.

Further, by making the ratio of the transfer times Tb and Tc high with respect to the cycle Ta of the drive signal 30, D
Since the time that can be spent transferring ATA3 becomes longer and it is not necessary to increase the frequencies of DATA3 and CLK2,
This is effective in reducing costs because it is not necessary to increase the speed of the control circuit and drive circuit.

As described above, one cycle of DATA3 is divided and transferred while avoiding the time zones of the rising and falling times of the drive signal. As a result, noise is not superimposed on CLK2, so CLK2 and D
The synchronization with ATA3 is not lost. Therefore, the circuits after the shift register of the drive circuit can drive the head normally without being different from the data desired by the control circuit, and can provide a recording apparatus capable of obtaining a high-quality image without deteriorating the image quality. Is possible.

Further, the ratio of the transfer time other than the rising time and the falling time (transition range) to the cycle of the drive signal can be set high, so that the time spent for the transfer of DATA3 becomes long, and DATA3 and CLK2
Since it is not necessary to increase the frequency of (1), it is possible to provide a low-cost printing apparatus that does not require high-speed operation of the control circuit and the drive circuit.

In this embodiment, DATA3 is divided into two equal parts and transferred at the transfer times Tb and Tc. However, by increasing the output groups and latches of the multiplexer of the drive circuit, further division into multiple parts is possible. Even with unequal division, the same effect as described above can be obtained. Also, DATA
May be transferred only during the transfer time Tb without being divided.

Further, in the present embodiment, the present invention is used for the recording apparatus having the ink jet type print head for ejecting ink, but the present invention is also used for the recording apparatus for the impact type print head using the piezoelectric element, The same effect can be obtained.

[0037]

As is apparent from the above description, according to the recording apparatus of the present invention, since the control circuit transfers the recording data to the drive circuit at a time which is not in the transient range of the electric signal, The adverse effect on the data transfer due to the noise generated by the current flowing in the transient region of the electric signal is prevented. Therefore, it is possible to favorably transfer the print data to the drive circuit, and it is possible to obtain a high-quality image without deteriorating the image quality. Furthermore, since the control circuit transfers the recording data to the drive circuit while the electric signal is being applied and except for the transient region of the electric signal, it is necessary to increase the frequency of the transfer of the recording data. Therefore, it is possible to provide a low-cost recording apparatus that does not require high-speed operation of the control circuit and the drive circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a drive circuit of a recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an electric circuit of the recording apparatus of the embodiment.

FIG. 3 is an explanatory diagram showing operation timings of the recording apparatus of the embodiment.

FIG. 4 is a cross-sectional view of an essential part showing an inkjet print head.

FIG. 5 is a block diagram showing a configuration of a drive circuit of a conventional recording apparatus.

FIG. 6 is a block diagram showing an electric circuit of a conventional recording apparatus.

FIG. 7 is an explanatory diagram showing operation timing of a conventional recording apparatus.

FIG. 8 is an explanatory diagram showing another operation timing of the conventional recording apparatus.

[Explanation of symbols]

 1 shift register 4 multiplexer 6 latch a 7 latch b 9 AND gate 12 output circuit 20 control circuit 21 drive circuit 54 partition wall 59a drive electrode 59b drive electrode 60 ground electrode

Claims (3)

[Claims] 1. A recording device for deforming a piezoelectric element by applying an electric signal to the piezoelectric element and recording characters, figures, etc. by the deformation, a drive circuit for applying the electric signal to the piezoelectric element, A recording device, comprising: a control circuit that transfers recording data to the drive circuit while excluding the transitional region of the electric signal and while the electric signal is being applied. 2. The recording apparatus according to claim 1, wherein the control circuit transfers the recording data to the drive circuit even when the electric signal is not applied. 3. The recording apparatus according to claim 1, wherein the deformation of the piezoelectric element deforms the volume of the ink chamber filled with the ink, and the ink is ejected from the ink chamber.