JPH10181011A - Driving method of ink jet head, and ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always discharge a normal ink by a method wherein a passage substrate is grounded at a GND electric potential, a pulse voltage to become + electric potential is applied to an individual electrode from the GND electric potential to transform a diaphragm, and the ink is discharged from a nozzle. SOLUTION: On the surface of a P type silicon substrate 2, a B dope layer 41 in which boron is diffused in 1×10E19 pieces/cm<3> or more, is formed, and an electric energy is applied to an individual electrode 31 from an ink jet head driver circuit 220 which is constituted of a CMOSIC. When Dn is made H in order to discharge an ink, transistors 141, 142 are turned on, and when a pulse V3 is applied, an electric potential of V3 is output to a SEGn terminal. At this time, the electric potential of a common electrode 17, i.e., a diaphragm, is always GND, and for this reason, the diaphragm 5 is negatively charged, and the individual electrode 31 is positively charged, and the diaphragm 5 is drawn by a static electric power and is driven. When Dn is L, the transistors 141, 142 are turned off, and a transistor 143 is turned on, and the GND electric potential is output to the SEGn terminal, and the diaphragm 5 is not driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for driving an ink jet head, an ink jet recording apparatus, and the like.

[0002]

2. Description of the Related Art Conventionally, as a technique for producing an ink jet head using a material capable of anisotropic etching, Japanese Patent Laid-Open Publication No.
The one shown in 5-50601 has been proposed.

When a P-type semiconductor such as Si is used for the flow path substrate, and when the polarity of the flow path substrate on the common electrode side with respect to the individual electrode is set to (-) polarity, the electric field to the Si substrate is in the opposite direction. As a result, there is a problem that a space charge layer is formed inside the flow path substrate material between the insulating layer and the ink, so that ink cannot be ejected or ink ejection efficiency is reduced.

To solve these problems, in Japanese Patent Application Laid-Open No. 7-125196, when P-type Si is used for the flow path substrate, the polarity of the flow path substrate is changed to (+).
The inkjet head was driven by applying a voltage to the individual electrode side with the (−) electrode.

However, if the channel substrate side is the (+) pole, the ink landing position of the ink on the recording medium is disturbed by the charging of the ejected ink droplets, making it difficult to ensure the print quality or to keep the ink in the channel substrate. The current leaks from the flow path substrate to other conductive members constituting the printer via the ink that has been applied and the ink attached to the substrate surface, causing a voltage drop of the common electrode,
There was a case where a problem that normal ink ejection could not be performed occurred.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and to provide a method of driving an ink-jet head and an ink-jet recording apparatus capable of stably printing quality and always discharging ink normally. With the goal.

[0007]

According to the present invention, there is provided a method for driving an ink jet head, comprising: (1) a flow path substrate having a plurality of ink flow paths, nozzles, and a vibration plate formed therein; The flow path substrate is made of P-type silicon, and B + is added to the flow path substrate by 1 × 10E19.
In a method for driving an ink-jet head, wherein the number of pieces / cm 3 or more is diffused, the flow path substrate is grounded to a GND potential,
Recording is performed by applying a pulse voltage from the GND potential to the + potential to the individual electrode to deform the diaphragm and eject ink from the nozzles.

(2) Further, each of the individual electrodes is connected to a first terminal of individual switching means having at least three terminals, and the individual switching means is connected to the first terminal.
And a second terminal to which a DC bias voltage is applied and G
A third terminal to which an ND potential is applied, wherein the first terminal is connected to the second terminal or the third terminal by switching, respectively, and the diaphragm is deformed and discharged. When the pulse voltage is applied by connecting the first terminal to the DC bias voltage side and the diaphragm is in a non-deformed state and in a non-ejection state, the first terminal is connected to the GND potential side. It is characterized by the following.

(3) In addition, each of the individual electrodes is connected to a first terminal of individual switching means having at least three terminals, and the individual switching means is applied with the first terminal and the pulse voltage. Second terminal and G
A third terminal to which an ND potential is applied, wherein the first terminal is connected to the second terminal or the third terminal by switching, respectively, and the diaphragm is deformed and discharged. When the first terminal is connected to a side to which the pulse voltage is applied, and when the diaphragm is in a non-deformed state and a non-ejection state, the first terminal is connected to a GND potential side. And

Further, the ink jet recording apparatus of the present invention comprises: (1) a flow path substrate having a plurality of ink flow paths, nozzles, and a vibration plate formed thereon, and a predetermined distance between the flow path substrate and the vibration plate. The flow path substrate is made of P-type silicon, and B + is added to the flow path substrate by 1 × 10E19.
In the ink jet recording apparatus, the individual flow path substrate is grounded to a GND potential, and individual switching means for switching the potential of the individual electrode to a driving pulse voltage side or a GND potential side, respectively, and the diaphragm Is deformed and ejected, the potential of the individual electrode is connected to the drive pulse voltage side, and when the diaphragm is brought into a non-deformed state and put into a non-ejection state, the potential of the individual electrode is set to GND.
Control means for controlling the individual switching means so as to be connected to the potential side.

(2) Further, the individual switching means is formed by a CMOS IC.

(3) In addition, the individual switching means inside the CMOS IC is constituted by a push-pull circuit connected to totem pole.

(4) The driving pulse voltage is inputted from outside the CMOS IC.

(5) Further, the individual switching means inside the CMOS IC is constituted by a bidirectional transmission gate.

(6) In addition, a housing grounded to the GND potential is provided, and the flow path substrate and the housing are connected.

[0016]

Embodiments of the present invention will be described below.

FIG. 1 is a schematic perspective view of an ink jet recording apparatus 310 equipped with an ink jet head 10 according to the present invention. The inkjet head 10 is mounted on the carriage 302 and ejects ink droplets onto the recording paper 105 guided by the platen 300. Carriage 3
Numeral 02 is arranged so as to be movable in parallel to the platen axis. The ink-jet head 10 is supplied with ink from an ink tank 301 via an ink supply tube 306. Of course, the inkjet head 10 itself may have an ink tank, and may be exchangeably mounted on the carriage 302 together with the ink tank.

The frame, which is a housing supporting the platen 300, is made of a plated steel plate (not shown) and is grounded to GND.

The ink cap 304 is attached to the carriage 30
When the inkjet head 10 is not ejected for a long time, or when ink ejection failure occurs and ink is sucked,
0 and is used to collect the waste ink in the waste ink reservoir 305 via the waste ink collection tube 308. When collecting the waste ink, an electric or manual pump 303 is used.

FIG. 2 is a side sectional view of the ink jet head 10. The inkjet head 10 has a laminated structure in which three substrates 1, 2, and 3 are overlapped.

The intermediate substrate 2 has an edge nozzle 4, a common ink chamber 8, an ink chamber 6 communicating with each nozzle, an orifice 7, and a vibration plate 5 also serving as a bottom wall of the ink chamber by etching a silicon substrate. ing. In the vicinity of the common ink chamber 8, a common electrode 17 is provided. On the surface of the silicon substrate 2, a B-doped layer 41 in which boron is diffused is formed. The B-doped layer 41 contains boron (B +) of 1 × 10E19.
Diffused more than individual / cubic cm, resistivity about 0.01Ω · cm
It has the following conductors.

Boric acid glass substrates 1 and 3 as an insulating substrate are anodically bonded with a silicon substrate 2 interposed therebetween. As a method of anodic bonding, the glass substrate 1 and the silicon substrate 2 are heated at a temperature of 300 to 500 ° C. and a voltage of 500 to 100 °.
The anodic bonding is similarly performed between the glass substrate 3 and the silicon substrate 2 by applying 0V. Ink is supplied to the common ink chamber 8 from above the upper glass substrate 1 via the ink supply tube 306, the connection pipe 16, and the supply port 14.

On the lower glass substrate 2, individual electrodes 31 are arranged in opposition to the diaphragm 5 together with the terminal portions 33 and the wiring lead portions 32 by ITO. The ITO 31 and 32 are covered with an insulating film 34. The insulating film 34 is made of IT
It may be provided on the silicon substrate side instead of the O side. From the inkjet head driver circuit 220, the individual electrodes 31
Is applied with electrical energy.

FIG. 4 is a plan view seen from AA in FIG. The diaphragm 5 also serving as the bottom wall of the ink chamber 6 of the silicon substrate 2 forms a capacitor between the diaphragm 5 and the individual electrode 31 provided on the glass substrate 3 via a gap (air). Diaphragm 5 has a thickness of 2 μm. The gap 9 is formed by etching the glass substrate 3 and joining the silicon substrate 2. This gap is 0.225 μm. Ink droplets 13 are ejected from the nozzles 4 and the recording paper 1
05 is recorded. The nozzle 4 is connected to the silicon substrate 2
Instead of being provided on the glass substrate 1, ink droplets may be ejected from the glass substrate 1 by vibrating the vibration plate 5. Further, instead of the glass substrate 1, a plate made of stainless steel or silicon having a nozzle hole for the nozzle 4 may be adhered to the silicon substrate 2 and ink droplets may be ejected from these nozzle holes. (Not shown)
Since these nozzle-opened members are grounded to GND according to the driving method of the present invention, even if they are formed of a conductive member, there is no potential difference from other members constituting the recording apparatus. This makes it possible to discharge ink stably without leakage, to select a material having good workability, and to make the inkjet head easier to manufacture.

When a positive voltage pulse is applied to the individual electrode facing the ink chamber communicating with the nozzle to be discharged by the driver circuit 220, the surface of the individual electrode is positively charged, and the surface on the diaphragm 5 side is negatively charged. . Therefore, the diaphragm is sucked by the electrostatic force and bends downward. Next, when the positive voltage pulse applied to the individual electrodes is turned off, the diaphragm returns to the original position, the internal pressure of the ink chamber rapidly rises, and ink droplets are ejected from the nozzles.

FIG. 3 shows how the potential of the basic drive pulse voltage waveform V3 input to the driver 220 changes with time. In order to eject two ink droplets to one pixel, two pulse voltages are applied for printing one pixel. In the present embodiment, the pulse shape is trapezoidal, Pwc1 = Pwc2 = 2 μsec,
Pwd1 = Pwd2 = 1 μsec, Pw1 = Pw2 = 1
4 μsec, Pwi = 62 μsec. Pwc
The diaphragm 5 is sucked into the individual electrode 31 by the portion, the ink is drawn into the flow channel at the time Pw, the diaphragm 5 is separated from the individual electrode 31 by the portion Pw1, the diaphragm 5 is released, and the flow channel is released. The ink inside is pressurized and ink droplets are ejected from the nozzles 4 to adhere and permeate the ink on the paper surface to form pixels.

The driver section 61 incorporated in the driver circuit 220 switches between applying the potential V3 or the potential GND to the head individual electrode terminal 33 by an input signal Dn.

FIG. 5 is a block diagram showing a drive control system of the ink jet head used in the ink jet recording apparatus of the present invention. The printer control circuit 201 is formed of a one-chip microcomputer, and is connected to a RAM 205, a ROM 206, and a CG (character generator) -ROM 207 via internal buses 202, 203, and 204 including an address bus and a data bus. The head drive control circuit 210 is controlled by the printer control circuit 201, and controls the print data DA via the data bus 211.
TA is output to the head driver circuit 220. The drive pulse V3 applied to the head driver 220 is formed by the head drive control circuit 210.

The head driver 220 is a CMOS-IC
And may be provided integrally on the inkjet head 10 or provided on an FPC (flexible substrate),
The inkjet head 10 may be unitized.

FIG. 6 is a block diagram of a CMOS-IC for the head driver 220. This head driver CM
The OS-IC has six drivers 61 for individual electrodes (SEG).
It has 4 bits. Reference numeral 62 denotes a level interface circuit for converting a voltage level of a signal from a logic system level to a head drive system level by a level shifter. 6
A latch circuit 3 is a 64-bit latch circuit for segment data latch. 64 is a shift register,
This is a 64-bit shift register for transferring segment data.

When discharging a 64-dot nozzle,
One CMOS-IC may be used, and two nozzles may be used to discharge a 128-dot nozzle. At this time, if the DO terminal of the first driver IC is connected to the 64-bit serial data input of the second driver IC, it can be used as a 128-bit driver IC.

A drive voltage pulse V3 having a voltage value of 31 V, a rise of 2 μs, a width of 14 μs, a fall of 1 μs, and a frequency of 16 kHz (each a Typ value) output from the head drive control circuit 210 is input to the V3 terminal. The drive voltage pulse Vp input from the V3 terminal is connected to the SEG driver 6. The print data DATA is input as 64-bit data as serial data via the bus 211, is subjected to serial-parallel conversion by the shift register 64, and outputs each nozzle data to the SEG driver 61.
At this time, the print data is a 64-bit shift register 6
4 and are latched by the latch circuit 63 when necessary data is obtained. A segment output SEGn is output based on the latched data.

The voltage waveform applied to the individual electrode will be described with reference to FIG. The driving pulse voltage V3 has a frequency of 1
Head driver 2 repeats Vh and GND at 6 kHz
20. H of the waveform of Dn is the drive voltage V3 side,
L indicates that each switch is switched to the GND side. At timing 1, when Dn is set to H in order to drive the nozzle and eject ink, V3 is output to SEGn. At this time, since the potential of the common electrode 17, that is, the potential of the diaphragm 5 is always GND, the diaphragm 5 is negatively charged, the individual electrode 31 is positively charged, and the diaphragm 5 is attracted and driven by electrostatic force. At timing 2, since Dn is L, SEGn becomes the GND potential and is not driven. At timing 3, driving is performed in the same manner as at timing 1.

As described above, the drive pulse V3 is generated by the CMOS
Instead of being created inside the IC, it is created outside the head drive control circuit 210 or the like and applied to the CMOS IC. As described above, by generating the driving pulse voltage V3 externally, even when one pixel is composed of a plurality or a large number of pixels and driven,
The switching frequency of Dn inside the OSIC is equal to or less than half of the frequency of the driving pulse V3, and the switching frequency of Dn only needs to be one pixel. Further, since the drive pulse V3 is generated externally, a high voltage (about 31
It is not necessary to create a high-speed pulse V) (approximately 2 μs for rising, approximately 1 μs for falling). Therefore, noise such as a mustache does not occur in the pulse waveform, the pulse waveform is not disturbed, and the inkjet head 10 can be accurately driven.

As shown in FIG. 2, the driver section 61 is more preferably a bidirectional transmission gate. In FIG. 2, when Dn is set to H, the transistor 14
1 and 142 are turned on, and VEG is applied to SEG regardless of the potential of V3.
3 can be output with low impedance. When pulse V3 is applied while Dn is H, SEGn
The potential of V3 is output to the terminal as it is, and the capacitor is charged to the discharge nozzle at the rise of the pulse V3.
The capacitor is discharged at the fall of the pulse V3. Dn
While L is low, the transistors 141 and 142 are turned off, the transistor 143 is turned on, and the GND potential is output to the SEGn terminal. Since the pulse width of the drive pulse V3 is included in the pulse width for switching the SEGn to HL, the discharge capacitor can be charged and discharged in accordance with the potential of the drive pulse V3 formed externally, and the timing can be quickly switched in the CMOS IC. No need to do. Therefore, the charge / discharge time of the capacitor can be shortened, and the CMOS
There is no noise or disturbance of the pulse waveform due to the timing change inside C.

FIG. 8 shows another embodiment of the driver IC. The driver IC 221 has a P-channel MOSFE
T144, N-channel MOSFET 145, resistor 1
46 is built-in. The FETs 141 and 145 are totem-pole connected to form a push-pull circuit.
The resistor Rd secures the output impedance of SEGn, and is connected in series with the capacitance of the head by connecting SEGn and the inkjet head to form an RC circuit.

FIG. 9 shows the relationship between the input Dn and the output SEGn when the driver shown in FIG. 8 is used. When a pulse of Dn is input with a drive pulse width, the SEGn output outputs Vp for the time of the drive pulse width, and the individual electrode 31 has a voltage pulse waveform equivalent to that of the circuit shown in FIG. Thus, the driver 221 does not need to input a high-voltage driving pulse voltage from the outside, and
The inkjet head 10 can be driven only by switching between the DC bias voltage Vp and GND internally. In this case, generation of spike noise due to ringing of the high voltage input pulse can be prevented, and a stable drive circuit and stable operation of the ink jet head can be ensured. Also,
When an IC is formed, the circuit itself is simplified and the number of built-in elements is small, so that the size of the entire IC can be reduced, so that the IC can be easily manufactured.

[0038]

As described above, according to the present invention,
The following effects are obtained.

The charging position of the ink on the recording medium is disturbed by the charging of the ejected ink droplets, making it difficult to ensure the printing quality, or by the ink held in the flow path substrate or the ink attached to the substrate surface. A current leaks from the flow path substrate to another conductive member constituting the printer, causing a voltage drop of the common electrode, thereby enabling normal ink ejection.

Since the transmission gate is employed, a current can flow in both directions, and charging and discharging can be accelerated regardless of the applied pulse voltage and timing.

Thus, it is possible to provide an ink-jet head driving method and an ink-jet recording apparatus capable of stably printing quality and always discharging ink normally.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an ink jet recording apparatus according to the present invention.

FIG. 2 is a side sectional view and a schematic diagram of a driving circuit of the inkjet head of the present invention.

FIG. 3 is an AA arrow line diagram in FIG. 2;

FIG. 4 is a waveform diagram of a basic drive pulse voltage according to the present invention.

FIG. 5 is a block diagram of a head drive circuit of the ink jet recording apparatus of the present invention.

FIG. 6 is an internal block diagram of a CMOS IC for a head drive circuit according to the present invention.

FIG. 7 is a timing chart of a head drive pulse according to the present invention.

FIG. 8 is a circuit schematic diagram of another CMOS IC for a driving circuit according to the present invention.

FIG. 9 is a timing chart of head drive pulses of the circuit of FIG. 8 according to the present invention;

[Explanation of symbols]

 2. Silicon substrate 3. Glass substrate 5. Vibration plate 10 Inkjet head 17 Common electrode (solid metal part) 31 Individual electrode 32 Individual lead Unit 61 SEG driver 210 Head drive control circuit 220 CMOS IC for head driver

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Ishikawa 3-3-5 Yamato, Suwa-shi, Nagano Prefecture Seiko Epson Corporation

Claims (9)

[Claims] A flow path substrate provided with a plurality of ink flow paths, nozzles, and a vibration plate; and individual electrodes disposed at predetermined intervals facing the vibration plate. The path substrate is formed of P-type silicon, and B + is 1 × 1
0E19 / cubic cm or more, a method of driving an ink jet head, wherein: the flow path substrate is grounded to a GND potential;
A method for driving an ink-jet head, comprising: applying a pulse voltage from ND potential to + potential to deform the vibrating plate and ejecting ink from the nozzles to perform recording. 2. The method according to claim 1, wherein the individual electrodes each have at least three electrodes.
The individual switching means is connected to a first terminal of the individual switching means having a terminal, wherein the individual switching means includes the first terminal, a second terminal to which a DC bias voltage is applied, and a third terminal to which a GND potential is applied. The first terminal is connected to the second terminal or the third terminal by switching the first terminal to the second terminal or the third terminal. When the diaphragm is deformed and discharged, the first terminal is connected to the DC bias voltage side. 2. The inkjet head according to claim 1, wherein the first terminal is connected to a GND potential side when the vibration plate is in a non-deformed state and is in a non-ejection state by applying the pulse voltage to the diaphragm. Drive method. 3. The method according to claim 1, wherein the individual electrodes are at least 3
The individual switching means is connected to a first terminal of the individual switching means having a terminal, wherein the individual switching means includes the first terminal, a second terminal to which the pulse voltage is applied, and a third terminal to which a GND potential is applied. The first terminal is connected to the second terminal or the third terminal by switching, and the pulse voltage is applied to the first terminal when the diaphragm is deformed and discharged. 2. The method according to claim 1, wherein the first terminal is connected to a GND potential side when the diaphragm is connected to an application side and the diaphragm is in a non-deformed state and a non-ejection state. . 4. A flow path comprising: a flow path substrate having a plurality of ink flow paths, nozzles, and a vibration plate formed therein; and individual electrodes disposed at predetermined intervals to face the vibration plate. The path substrate is formed of P-type silicon, and B + is 1 × 1
0E19 / cubic cm or more diffused, wherein the channel substrate is grounded to a GND potential, and individual switching means for switching the potential of the individual electrode to a driving pulse voltage side or a GND potential side, respectively; When the plate is deformed and ejected, the potential of the individual electrode is connected to the drive pulse voltage side, and when the diaphragm is brought into the non-deformed state and put in the non-ejection state, the potential of the individual electrode is connected to the GND potential side. And a control means for controlling the individual switching means. 5. The method according to claim 1, wherein the individual switching means is a CMOS.
The inkjet recording apparatus according to claim 4, wherein the inkjet recording apparatus is formed by an IC. 6. The ink jet printing apparatus according to claim 5, wherein the individual switching means inside the CMOS IC is constituted by a push-pull circuit connected to a totem pole. 7. The driving pulse voltage of the CMOSI
6. An input from outside of C.
The inkjet recording apparatus according to any one of the preceding claims. 8. An ink jet recording apparatus according to claim 7, wherein said individual switching means inside said CMOS IC is constituted by a bidirectional transmission gate. 9. The ink jet recording apparatus according to claim 4, further comprising a housing grounded to a GND potential, wherein said flow path substrate and said housing are connected.