JPS5856869A - Driving method for recording head of ink jet printer and driving circuit thereof - Google Patents

Abstract

PURPOSE:To obtain clear printing by a method wherein the rise time of a driving voltage waveform is set to be longer than the fall time thereof and thereby the velocities of ink particles from a plurality of nozzles are adjusted to be uniform. CONSTITUTION:In the driving circuit of a recording head, a charge is given from an emitter follower Q2 to a piezoelectric element C0 via a resistor R4 and an output voltage rising at a prescribed time constant appears at an output terminal I2 in a period T2 when a switching transistor Q1 is OFF. When the transistor Q1 is turned ON, the charge of the piezoelectric element C0 is rapidly released through a diode D2 and the transistor Q1. Accordingly, a waveform having a sharp fall can be obtained, a stable drive of ink particles having a small diameter can be performed, a time constant can be varied since a resistance R4 is variable, and thus a particle velocity from each nozzle can be made equal. Moreover, no air bubbles penetrate into nozzles and thereby excellent printing is enabled, since the fall is sharp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording head m-motion system of an inkjet printer and a so&! [Regarding the dynamic circuit] It is important that there is little air bubbles entering the nozzle, and that the ink particles ejected from the nozzle are easily atomized. A recording head drive system of an inkjet printer that can equalize the velocity of particles ejected from several nozzles and its O#A operating circuit will be described. The ink jet recording scissors control ink particles ejected from nozzle 0 of the paper head according to the one-character pattern K to print a desired O-shaped pattern on the paper κ disposed opposite the paper head k.

Kikama head is No. 11 (top view, No. 1 (b)
Kill'l! A number of piezoelectric elements Am to A, corresponding to the number of K substrates and nozzles, are formed so as to show the cross-section of II. I'm there ● 1 interval! Kl～
K●κ) Conduction path Ds#Dt+pressure weight us@Be@ink supply path Cs#Cme common ink iiiF# is formed,
A common ink chamber PK is provided with an inter supply port G for supplying ink. A drive circuit for the piezoelectric element AieAj'K is provided with a drive signal GO (
A lead wire LreLj is provided.

NstN spring is a nozzle-m one circuit GK is shown in Fig. 2 (
1) as shown in 5&. A configuration circuit as shown in Fig. 2(b)K is provided in order to apply a sliding tl type having a steep rise and a slow fall to the piezoelectric element AAeA'jK.〇In Fig. 2(b) , QI, Ql are transistors, R
● is the collector resistance, DI is the diode, Rl is the output resistance, and ReIRs is the bias resistance ●Vs-V- is the electrical resistance, C● is the capacitor, and is the equivalent circuit representation of the piezoelectric element● 1, Key In such a circuit configuration, as shown in Fig. 2 (aK), the driving force applied to the piezoelectric elements A, ~Anκ falls slowly. This has the disadvantage that the ink ejects from the nozzle with a large amount of air, which causes air bubbles to enter the nozzle after the ink is ejected, resulting in poor quality.Also, in the conventional circuit shown in Fig. 2(b), when voltage is applied to the piezoelectric element, Since the current also freezes in the resistor R1 connected in parallel with K1, there is a drawback that power consumption is significant and efficient driving cannot be performed. To provide a recording head drive system for an inkjet printer which allows good quality printing with less air bubbles entering the ink nozzles of an inkjet style jet recording device, and a recording head body circuit with less square consumption. 0 For the purpose of
I will explain this in detail.0 My younger brother Figure 3 shows the recording head O drive 1l of an inkjet printer.
Itl? Experimental data showing the relationship between the falling speed of the & shape and the stable printing area. When & is set to 300 μm J7, when the large stroke distance is 200 μm or less, the Figure 3 (
(b) ) shows the uniform pressure applied to the piezoelectric forceps K shown in Figure (1). It is fL*● And the ink droplets ejected from this %ONOXle are o84k
As shown by , tjI & 41k, the fall of K suddenly becomes larger as the ν time TD increases. Pl! In i2K, the vertical axis indicates the particle size of the ink droplet O. This is because the fall of the waveform O of the body of the piezoelectric element is drawn into the nozzle due to the time domain κ, rather than the length of the ink droplet. Reason κ such as ●ζ which shows that eruption 1llK depends]
By using the WA dynamic voltage in which the fall of the vertical voltage waveform O of the piezoelectric element is steep, it is possible to obtain a print pattern of good quality in the stable printing area K of the print head TM. It can be seen that Fig. 5 shows 1 inkjet grid/ta O head drive 111l.
This is experimental data showing the relationship between the If & type start-up speed at 9 speed and the speed of b ink particles ejected from the ink nozzle. In the K diagram, the horizontal axis indicates the time 1 when the drive waveform rises, and the vertical axis indicates the ink droplet velocity Jt. As is clear from the figure, κ
By adjusting the start-up time, the ink droplet speed can be adjusted to 1 k@, so when recording using a head with multiple nozzles, there is a difference in the ink droplet ejection speed of each nozzle. By adjusting the rising time of each waveform, the velocity of the stone ink particles ejected from each nozzle can be made equal.

FIG. 6 is a circuit configuration diagram of an embodiment of the present invention, and parts K equivalent to those in FIG. 2 are designated by the same reference numerals.
is the transistor Q. 9 variable resistors are connected between the Ivy and the capacitor (piezoelectric element) CaO, and D is the variable resistor R. , the piezoelectric capacitor Cρ connection point, and the transistor Q.
Between the bases of κ in the opposite direction Km there are six diodes 6X
．． is the input signal terminal. As shown in FIG. 7, the switching transistor Q. At the period Is when κ appears off, the piezoelectric element C. K charge is charged, and the output terminal T. of the wA dynamic circuit is charged. An output signal whose voltage increases with a constant time constant appears, and the switching transistor Q turns on.
Then, c period T. ) The charge stored in the piezoelectric element CI is transferred to a diode Da}transistor Q. Suddenly mK & comes out through.

A waveform with a steep falling edge is obtained, and the particle size is small, allowing stable driving. According to the wlA#Ih circuit k of the present invention, since the resistance R
Since the voltage value can be changed, it has the effect of equalizing the velocity of particles from each nozzle. When charging the piezoelectric bulker κ, the drive circuit of the present invention uses a km column κ resistor RI, unlike the conventional drive circuit. Since all of the current flowing from the lower transistor flows into the piezoelectric element C●κ, the current utilization efficiency is very high, and furthermore, the input terminal I is connected to the piezoelectric element C●κ. However, once the piezoelectric element is charged, the current from the transistor will stop flowing, so there is an effect of overcurrent guarantee. In the sickle head drive system and its drive circuit, the rise of the drive voltage waveform is slow, so the ink droplet velocity from the number of nozzles is equal to kll! 1, clear printing dots can be obtained, and the drive/voltage waveform has a steep fall in the 9th nozzle.
There is no air bubbles intrusion - good quality O printing is possible], and the single-circuit configuration of the sickle head is switched to the collector of the collector KiIfl& of the Opa transistor. An output resistor is provided, which is connected in series with the load OiIaκ, and a diode is connected between the connection point of this output resistor and the load to the base of the output resistor and the load. Due to its superior construction, it has zero power consumption and is effective in protecting against overcurrent.

[Brief explanation of the drawing]

No iml God) is a top view of the recording head O, No. 1 (a) is a sectional view of the recording head OJik part, No. 2ia(a) is a conventional O drive circuit, No. 2 is a conventional drive waveform diagram of the company, No. 3 Figure 31Ii1(b) shows the stability of the ink particles ejected from the nozzle.
Rattan 4m is a diagram showing the 11L diameter of the ink droplets ejected from the nozzle, fg5 is a diagram showing the rise of the sliding waveform and the ink droplet connection JtO relationship. Figure 7 is a drive voltage waveform diagram.Q. , Q■: transistor, R-: collector resistance, RI
: Output resistance, B. ．． R●: Paianu resistance, V: 竃＠, D
Sleeping: Diode, C●: Piezoelectric element●362-363-1

Claims (3)

[Claims] (1) A drive system for an inkjet record head in which a drive voltage is applied to the piezoelectric element k of an inkjet distributing head having a nozzle for ejecting ink particles and a piezoelectric element to eject ink in the nozzle. In,
A recording head sliding system for an Interji printer, which is characterized in that the rise time of the front drive voltage waveform O is set to be longer than the fall time of the armpit drive voltage waveform O. (2) A piezoelectric element K which receives a voltage pulse and causes ink particles to be ejected from a plurality of nozzles. A switch which receives a base κλ force in the Kikama head motion circuit of an inkjet printer which supplies the voltage pulse. a switching transistor; a collector (or switching transistor) of the switching transistor;
A resistor (K41) connected in series with the piezoelectric element; (1) one end of the series resistor on the piezoelectric element side; (1) a collector (or emitter) of the switching transistor; ) between κ
1. A recording head drive circuit for an ink cartridge printer, comprising a diode connected in a direction K. (3) The scope of the patent request as 4tgI1 is that the resistor connected in series with Sukeki is a variable temperature resistor that can set a resistance value within a range that can equalize the rate of decline of ink droplets from each nozzle. Section (2) describes @0 inkjet printer O recording head rotation circuit.