JPS5836456A - Recording head - Google Patents

Abstract

PURPOSE:To obtain a recording head which is small, high-density-packaged and safe in a large current countermeasure as well by a method wherein a heating unit is provided on an insulating layer placed on a conductive plate and the conductive plate and the heating unit are connected electrically. CONSTITUTION:A heating unit Hi is provided on an insulating layer IS and on it is equipped a conductive base CD. A selecting electrode li for applying picture element signals selectively to the heating unit Hi and a common electrode L are provided on the heating unit Hi and a power source HV is connected to them. The output terminal of a transistor array TA is connected to each selecting electrode li and a picture element selecting electrode Pi is connected to at least one of block selecting electrodes in the input terminal. A grooved plate GL1 is made by providing a grooved pattern on a glass plate and is bonded and integrated with a substrate having a heating unit to form an ink jet recording head.

Description

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the number of electrodes, substrates, etc. of a recording head that performs recording using a heating element is 1 Kml.

In conventional seeding systems, there were problems with the electrode wiring for driving a large number of heating elements.
Various modifications and improvements have been made since the publication of No. 736.

However, there are still some difficulties in terms of high density mounting, miniaturization, large current countermeasures, etc.

The present invention aims to solve the above-mentioned difficulties.
This will be explained below according to the drawings.

In FIG. 1, one end of each of a large number of heating elements IH1 to 56H32 is connected in common, and the collectors of control elements, such as transistors IT1 to 56T32, are connected to each other end. The nine transistors ITI to IT32 are considered as one chip, and the transistor array terminals of each chip are connected to each chip selection switching element MDt to MD56 as a common terminal, and the transistors ITI to tT32, . . . of each chip are connected to each chip selection switching element MDt to MD56.
. . , the bases of those located at relative positions 56T1 to 56T32 are connected to a common pixel information input terminal PI-P32.

For example, to make the heating element IHI generate heat, close the chip selection switching element MDI, open MD2 to 1D56,
Apply bulk information to terminal PIKIii. This driving voltage causes the transistor ITIFi4a to become HV-IHI-IT.
The heating element IHI generates heat due to the I-MDI-7-S EA circuit. This and the collector transistors of the gate transistors IT2 to IT32 are biased in the forward direction, but there is no pixel information input signal to P2 to P32. Ninth IT2 to IT32 do not generate heat.

Further, since MD2 to MD56 are open, the pixel signal supplied from Pl flows only to the transistor lT1, and only the heating element lH1 generates heat.

As mentioned above, during chip selection switching, MD1 to MD
By selecting the combination K of closing the gate 56 and applying voltage to the pixel information input terminals P1 to F32, it is possible to selectively cause the target heating element to generate heat.

FIG. 92 shows an example of a drive circuit in which a common base wrinkle transistor array is used instead of the Niotsuta common type as shown in FIG. This utilizes the current amplification rate of each transistor in the array configuration to reduce the current value on both the individual two-pots on the array and the external lead wire of the common base, reducing the load on the drive circuit. At the same time, when drawing out the bonding wires from the array, there is an advantage in that special attention to current values and the like need not be taken.

Figure 3 shows each element in the example as a field-effect transistor (PET).
), which reduces drive power and at the same time
The device characteristics of short storage time and short switching time enable high speed performance, and the drive circuit can be simplified due to its transfer characteristics.

It is easy to understand that the gates in Figure 9@3 can be made to have a common gate m, similar to Figure 2. There is no problem even if the element of 9II1wJ is composed of a bipolar transistor (or even an NPN) transistor or an N-channel FE.
PNP instead of T
It is also clear that the polarity of the power supply can be reversed by using ITI.

Figure #I4 is a cross-sectional view of an example of the recording head according to the present invention, in which a heating element Hi is provided on an insulating layer I8, and a conductive substrate CD is placed below it.
and a substrate H8.

The insulating layer I8 not only has the purpose of electrical insulation, but also functions as a heat storage layer for controlling the flow rate of heat generated by the heating element Hi.

The heating element HiK formed on the insulating layer layer 8 is further provided with a selection electrode 7 for selectively applying a pixel signal to the # heating element.
1 and a common electrode are formed as shown in the figure. This common electrode is provided commonly to all the heating elements Hi, and is provided on the conductive substrate C.
Power source HV is connected via D. An output terminal of a transistor array T is connected to each selection electrode L. t
At least one of the block selection electrodes and the pixel selection electrode Pi are connected to the input terminal of the transistor plate T.

The fifth example shows another real-axis embodiment of the recording head of the present invention, in which an insulating substrate I8' is formed under the conductive layer CD, and the substrate H& is made conductive and used as an electrode for the ground potential Em. be. It is clear that eight ground potentials may be connected to the nine conductive layers CD, and the power supply potential HV may be introduced from elsewhere, or the power supply potential HV may be introduced into the substrate H8. The substrate H8 functions as a heat sink for the heating element 1 (i).

Materials for the conductive layer include metals such as mulberry and Au, and materials for the heating element include ter'i, ZrBme Hf&+
Ta*N IW, Ni-Cr, thick film resistor (P'd-A
A normal resistor such as 8-hole resistor (G series, Ru series, etc.) is used.

In addition, it is also desirable to provide a thin insulating protective layer on the surfaces of the electrode layers Pi, ji, Di, etc., the heating element layer H5, etc. for the purpose of preventing mechanical friction and the like. For the connection between the common electrode and the conductive layer CD, a through water hole TH as shown in IIE6#AK may be used, or a large number of selective electrodes may be used.
It is also effective to alternately provide multiple layers of conductive layers and insulating layers, which serve as electrodes, in order to form them within one plane with more margin. Further, for ease of attachment and detachment, it is preferable to connect the connector through contact pieces Ci and CHK.

Figure 7 shows a grooved pattern formed on a glass plate.
Create LI, then connect the heating element to board and grooved Ij as described above.
This shows an example in which an inkjet recording head is made by adhering and integrating with GLt.

Figure Is8 shows the inkjet recording head block in Figure 7 assembled in full multi-layered form, and one common heat sink [
They are arranged alternately above and below H8. In the figure, the odd-numbered blocks CDl and CD are on the top surface of the heat sink H8.
a, ... CDn-t, even number block CD2 on the bottom surface
．． CD4. ...CDn1 joins. Ink IK is supplied to each block from an ink tank IT, an ink pipe IP, each block common distribution pipe OF, BP, and each block distribution pipe FPI to FPnK via grooved plates GLI to OLm.

Tmu1 and TAn are transistor arrays that are the same as those described above, and each selection electrode l on blocks CDl to CDn
! 1-1j32. Due to this zigzag arrangement, which is connected to ports D1 to D, etc., the orifice interval Q, that is, the interval between the heating elements, becomes the same as shown in Fig. 9, which is preferable.

@10, 11, 12 WJFiJIE 7, 8, 9 is a diagram for explaining an example of the raw salt recorded by the recording head of Figures 7, 8, and 9.

A recording liquid whose tip is formed into a nozzle, which constitutes a recording head.
If only Kri in IW is used, recording liquid IK is supplied from the direction of orifice P. Now, in the part of the width Δl in the liquid 1 [Wt at a distance of 7 from the orifice OF, the heating element HIK
When an electric pulse is applied, the cough heating element H1 starts to increase in temperature. When the heating element H1 becomes higher than the vaporization temperature of the recording liquid in the chamber Wt, Kfi bubbles B are generated on the heating element M1. As the temperature of the bubble BFi heating element H1 further increases, it grows and rapidly increases its volume.

As a result, the pressure in the liquid gwI increases rapidly, and the recording liquid existing in Δj by the volume increased by the bubble B rapidly moves in the direction of the oriice OF and in the opposite direction P. A portion of the recording liquid present in the portion 7 in the liquid 6w is discharged from the oriice OF. The ejected round recording liquid becomes a liquid column and connects to the orifice OPK.When the bubble B reaches its maximum, the liquid column running from the orifice OF stops growing, but the tip of the liquid column has not reached 90 degrees until this point. It stores the kinetic energy seen. 9 bubbles B is liquid 31i W
When it collides with the ceiling surface of the 61st part of 1, the force changes its direction in the longitudinal direction of the orifice, and the liquid column propulsive force further radiates the temperature of the 1 heating element Hr to the substrate side and falls. Due to the temperature drop, the bubble B begins to shrink in volume a little later than the point at which the electric pulse ends. Qi/I
With the volume contraction of IB, the recording liquid in the portion of the liquid column grown from the orifice OF near the orifice OF is pulled back to @Wl.

As a result, the kinetic energy at the tip of the liquid column and the kinetic energy of the liquid column O near the orifice It is attached to a predetermined stirrup on the recording member PP. When the bubble B on the heating element H1 disappears, the volume of the recording liquid drawn back into IIWl is smaller than the volume of liquid II[W10, causing the liquid level (meniscus) to retreat from the Oriice OF surface.
The recording liquid is always supplied from the P direction, and the meniscus gradually returns to its original state 11.

The size of the droplet ID discharged from the orifice OF is determined by the amount of thermal energy applied, the width of the portion Δl that is affected by the thermal energy, the inner diameter d of the liquid 1iIW, and the distance from the orifice OF to the heating element H1t! , depends on the device conditions such as the pressure applied to the liquid IKK, or the physical properties of the material such as the specific heat, thermal conductivity, coefficient of thermal expansion, and viscosity of the liquid IKK.

FIG. 2 tO to t9 are schematic diagrams showing the ejection process of recording liquid (hereinafter referred to as ink), in which an orifice OF, an ink chamber W, and a heating element H1 are shown, and the ink is supplied from an arrow P. The boundary liquid level (meniscus) between the ink IK and the outside air is shown by IM. Let B be the bubbles generated on the heating element H1. Figure 3) represents 1 fil of the driving electric pulse, and to to t9 indicate the times corresponding to Figure 2 electric currents 0) to 9). Figure 3B
) is a diagram showing the temperature change of the TFi heating element H1, Figure 3C)
indicates the change in volume of bubble B. At tO), the state before ejection is shown, and at the intersection tp between tQ) and tl), an electric pulse E is applied to the heating element HIK. As shown in tp), the temperature of the heating element H1 starts to rise at the same time as the driving pulse E is applied. 11) is in good condition as the temperature of the heating element exceeds the vaporization temperature of the ink, and bubbles B begin to form and the liquid level I
M indicates a state in which the bubble B [therefore expands in proportion to the amount of pressure applied to the ink IK] from the orifice surface. At t2), the bubbles B further grow and the liquid level IM further expands under good conditions.

At t3), the electric pulse E falls as shown in Figure 3), and when the temperature of the heating element H1 reaches the maximum as shown in Figure 3B), the liquid level IM further expands. t4) F1 As shown in Figure 3 B), the heating element temperature T has begun to fall, but as shown in Figure 3 C) K, the volume of bubble B has reached its highest level, and the liquid level IM continues to swell. forms a liquid column. At t5), the bubble volume B begins to shrink. Therefore, the ink IK is drawn into the ink chamber W by the amount that the air bubbles B contract with respect to the liquid level IME that has blown out from the Oriice OF. As a result, the liquid level IMFi arrow Q
A constriction occurs in the area. At tg), the bubble B further shrinks and separates into the droplet ID and the liquid surface IM'. t7
), the droplet ID is ejected and flies, the bubble B further contracts, and the liquid surface IM' further approaches the oriice OF surface. t
In g), the bubble B is about to disappear, and the liquid level IM further recedes and is drawn into the inner surface of the bubble through the orifice OF. At tQ), ink IK is supplied, and then the state returns to tQ).

In the case of a recording head using the above principle, if the heating element is placed far from the orifice, it will be impossible to eject droplets or the efficiency will decrease, so it is better to place the orifice and the heating element as close as possible. .

The present invention is also extremely suitable for such cases.

[Brief explanation of drawings]

Figure @1 is an example of a circuit that can be used in the present invention, Figures 2 and 3 are other examples, Figures 4 and 5.6 are head configurations of the present invention, and Figures 7.8.
Figure 9 is an application example diagram, and Figures @10, 11, and 12 are diagrams explaining the principle. IHI~56) 132... Heating element lT1~56T32... Control element I, /i, Pi... Electrode CD... Conductive plate Is... Insulating layer GL... Recording liquid chamber Applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) A Q head characterized in that an insulating layer is provided on a conductive plate, a heating element is provided on the insulating layer, and the conductive plate and the heating element are electrically connected. (1) A recording head according to item 11, characterized in that a control element for driving the heating element is arranged on the insulating layer. The recording head according to item (1), characterized in that droplets are formed by a heating element.