Ink jet recording head with adjustable temperature sensor and ink jet recording system having the same

An ink jet recording head includes an ink discharging portion having a discharge opening for discharging ink, a substrate having an electrical/thermal converting element for generating thermal energy supplied to the ink discharging portion and used to discharge the ink, and a temperature detecting element, and an information bearing means for carrying information providing the feature of the temperature detecting element. The output from the temperature detecting element are used to adjust the temperature of the ink jet recording head.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The present invention relates to an ink jet recording head and an ink jet 
recording system having such head, which are used with a copying machine, 
facsimile, word processor, output printer of a host computer, video output 
printer and the like, and more particularly, it relates to an ink jet 
recording head and an ink jet recording system having such head, wherein 
electrical/thermal converting elements and functional elements are 
disposed on a common substrate. 
The present invention further relates to a temperature adjusting apparatus 
used with a recording system, and, more particularly, it relates to a 
temperature adjusting apparatus which includes a plurality of similar 
analogue sensors for detecting the surrounding condition (for example, 
temperature) and wherein the surrounding condition is measured by 
receiving the outputs from such sensors through an amplifying circuit to 
adjust the temperature of a recording head of the recording system. 
Related Background Art 
There has been proposed a recording head wherein an array of 
electrical/thermal converting elements is formed on a single crystal 
silicon substrate, functional elements such as an array of transistors for 
activating the electrical/thermal converting elements are arranged outside 
the substrate, and the electrical/thermal converting elements are 
connected to the transistor array through a flexible cable, wire bonding 
and the like. 
In order to simplify the construction of the above-mentioned recording 
head, to reduce the number of bad parts in the head production line, and 
to improve the uniformity and/or reemergence of the features of various 
elements, an ink jet recording system having a recording head wherein 
electrical/thermal converting elements and functional elements are 
arranged on the same substrate has been proposed, as disclosed for example 
in the Japanese Patent Laid-open No. 57-72867. 
Although the above-mentioned recording head is excellent, there is a room 
for further improving the recording head and the recording system to meet 
the requirements regarding higher speed of operation, lower energy 
consumption, better integration, cost decreases and/or higher reliability 
strongly requested in the recent recording systems. 
In order to gain success in the commercial base, a recording head having a 
high level of performance must be provided with a low cost. To this end, 
it is necessary to provide an inexpensive recording head wherein the 
functional elements are integrated with high density, an area of a chip 
forming the substrate of the recording head is reduced, and a number of 
substrate 8 can be obtained from a single wafer. 
This can be referred to regarding not only a driving circuit but also 
various elements (typically, a temperature sensor) for performing good 
recording. 
In the above-mentioned ink jet recording head, the recording is effected by 
discharging the liquid such as ink by the use of thermal energy generated 
from the electrical/thermal converting elements including heating 
resistive members. When such recording head is activated, the temperature 
of the recording head is gradually increased as the recording operation is 
continued due to the fact that a part of the-thermal energy generated is 
accumulated in the liquid and due to other reasons. 
The increase in the temperature of the recording head affects a bad 
influence upon the viscosity of the ink, generation and growth of the 
bubble and the like, thus changing the amount of the discharged ink, and 
accordingly, the diameter of dots recorded on a recording medium. This 
results in the deterioration of the image quality, which should be 
avoided. 
To the contrary, a recording factor control for decreasing the temperature 
of the recording head on the basis of the detected temperature of the 
recording head (for example, a control effected by stopping the recording 
operation or by using a Peltier element) has been proposed in the past. In 
order to obtain the parameters for the above control, a temperature 
detecting element acting as a means for detecting the temperature of the 
recording head was provided for giving the output information for 
effecting such control. One example is shown in FIG. 1 illustrating a 
schematic perspective view of a recording head 10'. 
As is apparent from FIG. 1, electrical/thermal converting elements are 
formed at an end of a semiconductor substrate 51, and a top plate 52 
including a liquid chamber therein is disposed on the substrate to define 
orifices 53. A temperature detecting portion is arranged on a mother board 
54 at 60 or on the semi-conductor substrate 51 at 70. Concrete examples of 
the temperature detecting portion are shown in FIGS. 2A and 2B. 
FIG. 2A shows an example wherein a thermistor 61 acting as a temperature 
sensor is mounted on the mother board 54. In this arrangement, it should 
be noted that the disadvantage will arise regarding the number of parts, 
and thus, in the production line since the thermistor 61 must be added as 
a discrete element. 
On the other hand, FIG. 2B shows an example wherein a diode 71 having the 
P-N connection is formed on the semiconductor substrate 51 made of single 
crystal silicon material by the semiconductor process and a temperature 
sensor is provided by the use of the diode feature. That is to say, it is 
possible to achieve the higher functionality, higher integration and cost 
decreases by forming the temperature sensor, by means of the semiconductor 
process, on the substrate on which the electrical/thermal converting 
elements are disposed. Incidentally, the reference numeral 72 denotes an 
aluminium electrode, and 73 denotes an insulator layer made of SiO.sub.2. 
Although the recording heads can be manufactured in the same production 
line, dispersion in ink discharging features of the recording heads will 
occur. In order to correct or compensate such dispersion, a method wherein 
the information corresponding to the electrical/thermal converting 
features of the electrical/thermal converting elements, and thus, the 
discharging feature is previously formed on the recording head, for 
example in the form of electric resistors, and the recording head is 
driven by determining the discharging signal as the recording factor on 
the basis of such information has been proposed. 
However, even if such method is used, under the irregular or non-uniform 
usage of the recording head, the poor discharge of ink will occur, thus 
worsening the image quality. Particularly, it was found that the 
deterioration of the image quality occurs noticeably in the recording 
systems having a high level of performance wherein the recording is 
effected while adjusting the temperature of the recording head. 
As a result of a number of tests and experiments repeatedly performed by 
the inventors of this invention, it was found that such deterioration of 
the image quality mainly depends upon the change in temperature dependence 
of the detection output due to the dispersion in the inherent features of 
the temperature sensors themselves for the recording head, rather than the 
time-to-time change or the environment dependence of the 
electrical/thermal converting feature. However, this problem cannot be 
solved easily. 
That is to say, in the substrate for the recording head using an ink jet 
recording method, for example as disclosed in U.S. Pat. No. 4,723,129 
(Endo et al), the electrical/thermal converting elements capable of 
generating the thermal energy enough to cause the change in the condition 
of the ink and to discharge the ink from a discharge opening must be 
formed or provided. On the other hand, since the functional elements for 
driving the recording head and for detecting the temperature of the head, 
such as diodes, transistors and the like have the features depending upon 
the change in temperature (i.e., temperature dependence features), these 
must be activated under the temperature condition which is stable as long 
as possible. 
In other words, in order to arrange two kinds of elements having 
incompatible inherent features on the same substrate (the meaning of the 
words "on the substrate" also includes the case where the functional 
elements are formed in the substrate) and to activate these elements 
properly, unique constructions or arrangements of a recording head and a 
recording system must be devised under a new conception. Of course, it is 
also requested that such constructions be provided in an inexpensive 
manner. 
Now, FIG. 3 shows an example of a conventional measuring device for 
measuring the surrounding (environmental) condition, such as for example, 
a temperature. In FIG. 3, the reference numerals D denotes a diode acting 
as a temperature detecting sensor; Al, A2 denote amplifiers; C denotes a 
CPU forming a main portion of the measuring device. In this way, when the 
input level from the diode D which is an analogue sensor is measured, 
conventionally, it was practical that the output from the sensor was 
level-changed by means of the amplifiers (A1, A2); in this case, the error 
inherent to the circuit itself, i.e., the error derived from the offset 
voltages of the amplifiers and/or the rated error of the circuit elements 
was adjusted or compensated by variable resistors (VR1, VR2) of the 
amplifiers. That is to say, as shown in FIG. 4, with respect to the 
feature of temperature T-output value V of an ideal amplifier, a circuit 
error such as .DELTA.T will occur in effect. Thus, when the outputs of the 
amplifiers at a reference temperature T0 have values as A and B, these 
values are adjusted to have a value of V0 by means of the variable 
resistors (volume). 
However, in such a conventional example, although, if a number of systems 
(detection systems) each comprising the sensor and the amplifiers (i.e., a 
number of positions to be adjusted) is small, the production cost and/or 
the adjusting time are not badly influenced, such problem will become 
gradually noticeable as the number of such systems increases. 
SUMMARY OF THE INVENTION 
An object of the present invention is to solve the above-mentioned 
conventional drawbacks and to provide a recording head and a recording 
system having high ability, which can perform recording at a high speed 
with high resolution stable for a long time. 
Another object of the present invention is to provide an inexpensive 
recording head wherein electrical/thermal converting elements and 
functional elements are disposed on the same substrate, and an inexpensive 
recording system having a temperature adjusting function of high ability. 
A further object of the present invention is to provide a recording system 
and a temperature adjusting apparatus which can perform the temperature 
adjustment properly without increasing the manufacturing cost and/or the 
dimension thereof and without lengthening the adjustment time, even if the 
number of the above-mentioned systems is increased. 
A still further object of the present invention is to provide an ink jet 
recording head comprising an ink discharging portion having a discharge 
opening for discharging ink; a substrate having an electrical/thermal 
converting element for generating thermal energy supplied to the ink 
discharging portion and used to discharge the ink, and a temperature 
detecting element; and an information bearing means for carrying 
information providing the feature of the temperature detecting element. 
Another object of the present invention is to provide an ink jet recording 
system comprising an ink jet recording head used for forming a desired 
image on a recording medium by discharging ink from a discharge opening in 
response to a predetermined input signal; and a drive controlling means 
for controlling an operation of the ink jet recording head. It further 
comprises a temperature adjusting means having a detecting system 
including a detecting element for detecting the environmental condition 
surrounding the ink jet recording system, a memory means for storing an 
output value from the detecting system regarding an output of the 
detecting element as a reference or the result obtained by performing a 
predetermined calculation with respect to the output value, and a 
correcting means for correcting an error of the detecting system on the 
basis of the contents stored-in the memory means. 
According to the present invention, since the pattern acting as the 
information bearing means for bearing or carrying the information 
providing the feature of the temperature detecting element is previously 
formed on the recording head, it is possible to correct the dispersion in 
the temperature detecting elements obtained by the semiconductor process, 
with a very simple method and arrangement, and to perform the proper 
temperature control. 
Further, in the present invention, for the purpose of the recognition of 
the error AV conventionally adjusted by the volume, the data representing 
the characteristics of the circuit such as the value .DELTA.V, V value at 
the point A and the like are stored in the memory means comprising an 
involatile memory and the correction of the measured values is effected on 
the basis of the contents stored in the memory. 
With this arrangement, according to the present invention, since the 
reference value is previously set as the output of the detecting element, 
and the output value of the detecting system or the result obtained by 
performing the predetermined calculation using such output value is stored 
in the memory means, the error in the detecting system used is corrected 
on the basis of the contents stored in the memory means, when the control 
is effected in accordance with the environmental condition. Thus, it is 
possible to obtain the measurement result with high accuracy and to 
perform the proper temperature adjustment, without adjusting the rated 
error of the detecting element and/or the output voltage level regarding 
the offset voltage of the amplifying circuits.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be explained in connection with embodiments 
thereof with reference to the accompanying drawings. However, the present 
invention is not limited to such embodiments, but may be as any types 
which can achieve the objects of the invention. 
Embodiment 1 
First of all, a temperature feature of a diode acting as a temperature 
detecting element applicable to the present invention will be described. 
FIG. 5A shows an equivalent circuit for a diode. In FIG. 5A, when a current 
flows from a direction A to a direction B, a voltage reduction V.sub.F is 
created in a normal direction of the diode 71. In general, the voltage 
reduction V.sub.F in the normal direction varies in response to the change 
in the temperature. Thus, it is possible to detect the temperature by the 
use of such change in the voltages. 
Further, the voltage reduction V.sub.F also varies in accordance with the 
density of current flowing in the diode. If the current is maintained at a 
constant value, the voltage reduction detected in the diode 71 in the 
normal direction will be determined only as a function of the temperature. 
That is to say, the relationship between the voltage reduction V.sub.F and 
the temperature will be expressed by the following equation (1): 
EQU V.sub.F .alpha.KT/q 1n(I.sub.F /I.sub.s) (1) 
Where, K and q are constants referred to as "wave number" and "charge of 
electron", respectively. Further, I.sub.s is a given current constant 
derived from the area of the P-N connection, I.sub.F is a current value in 
the normal direction, and T is an absolute temperature. 
Accordingly, if the current value I.sub.F in the normal direction flowing 
in the diode is fixed, the voltage V.sub.F in the normal direction can be 
expressed only as a function of the absolute temperature T. That is to 
say, the following relationship is given: 
EQU V.sub.F .alpha..sigma..sub.T 
where, 
EQU .sigma.=K/q 1n (I.sub.F /I.sub.S) (2) 
FIG. 5B is a graph showing the measurement result presenting the 
relationship given by the expression (2). 
As apparent from this graph, the values of V.sub.F is dispersed due to the 
dispersion derived from the diode production or manufacturing line. 
According to FIG. 5B, in a recording head B manufactured in the same 
production line as a certain recording head A, the dispersion of 30 mV 
will occur at a temperature of 25.degree. C. (.sigma..sub.T). Converting 
this into the temperature, a detection error of 15.degree. C. will occur. 
If these two recording heads are used to be driven under the same 
condition, it will be impossible to detect the correct temperature, thus 
providing the insufficient power at the lower temperature, which causes 
the poor ink discharging and/or overheating of the recording head due to 
the inadequate control at the higher temperature, which causes the 
deterioration of the image quality. Further, the service life of the 
recording heads will be shortened. 
According to this example, since the information bearing means for carrying 
the dispersion information of the diodes is disposed on a wiring substrate 
integrally fixed to a semiconductor substrate on which the temperature 
detecting diode is arranged, the dispersion information inherent to the 
recording head is detected in a main body side, thereby permitting the 
correct temperature control. 
FIG. 6 is a schematic perspective view of a recording head according to an 
embodiment of the present invention. 
The recording head 10 is constituted by a substrate 14 arranged on an 
aluminium base plate 11 and on which a temperature detecting sensor 13 is 
formed, a top plate 15 including a liquid chamber therein and disposed on 
the substrate, and a PCB plate 12 on which the wirings extending from the 
substrate 14 to an electric connector portion 16 are disposed. Further, on 
the PCB plate 12, a sensor rank detecting pattern 17 acting as an 
information bearing means is formed. The substrate 14 is electrically 
connected to the PCB plate 12 by a bonding wire and the like (not shown), 
and further, the plate is electrically connected to a main body of a 
printer through the electric connector portion 16 so that the head 10 is 
driven by a drive controlling circuit arranged in the main body side. 
FIG. 7 shows a portion of the sensor rank detecting pattern 17 of FIG. 6 in 
an enlarged scale. In the illustrated example, four patterns 17-1, 17-2, 
17-3 and 17-4 are used. Portions 18 to be bored correspond to three areas 
a, b and c encircled by broken line circles. The pattern 17-4 is 
electrically earthed when the recording head is mounted on the recording 
system. By selectively boring the portions a, b, c, the bearing means for 
carrying the ranking information is provided. Further, by electrically or 
optically reading the selectively opened or short-circuited pattern, it is 
possible to rank the temperature sensor. In the illustrated example, the 
ranking for three bits, i.e., the ranking into eight ranks will be fully 
explained. 
FIG. 8 is a schematic perspective view for explaining the substrate 14 of 
FIG. 6. 
In FIG. 8, the reference numeral 110 denotes electrical/thermal converting 
elements which are is formed on a semiconductor substrate 140 by a process 
which will be described later. The reference numeral 103 denotes heating 
resistive layers; and 104, 104' denote a pair of electrodes. 
The reference numeral 120 denotes diodes acting as driving functional 
elements which are connected to the corresponding electrical/thermal 
converting element in series by the electrode 104 s0 that the current 
leakage is prevented when another electrical/thermal converting element is 
driven. 
The reference numeral 210 denotes diodes acting as temperature detecting 
functional elements (temperature sensors) which are arranged on both sides 
of the semiconductor substrate 140 with the interposition of the 
electrical/thermal converting elements 110. These diodes are formed 
simultaneously with the formation of the driving diodes 120 by the process 
described later. 
The reference numeral 130 denotes heating members acting as functional 
elements for heating the ink, which can perform heating control by 
controlling the current supplied on the basis of the outputs from the 
temperature sensors 210. These heating member 130 are also arranged on 
both sides of the semiconductor substrate 140. 
The reference numeral 160 denotes a wiring portion for the 
electrical/thermal converting elements, which is arranged between an array 
of the electrical/thermal converting elements 110 and an array of the 
driving diodes 120. The reference numerals 170 denote pats for providing 
the electric connection to the external equipments. 
Incidentally, while FIG. 8 shows a portion of the substrate 14, an opposite 
portion of the substrate has a symmetrical arrangement. 
The concrete ranking is shown in FIG. 9. In the recording head as shown in 
FIG. 8 used in this example, the dispersion of the values V.sub.F is 
normally included in the following range: 
EQU 0.540.ltoreq.V.sub.F .ltoreq.0.579 
And, thus, there occurs the dispersion of about 40 mV. If the sensors are 
used as they are, there will arise the detection temperature error of 
about 20.degree. C. However, by controlling the dispersion of the sensor 
diodes by means of this method and by discriminating the rank of the 
diodes, the dispersion thereof can be reduced to 1/8 of the original 
dispersion, and thus, it is possible to suppress the dispersion within a 
range of about 2.2.degree. C. 
FIG. 10 shows a reading circuit arranged in the main body side of the 
recording system when the head so ranked is used. 
In this circuit, four reading pats 17-1 to 17-4 are provided, in which the 
pattern 17-4 is earthed. The three patterns 17-1, 17-2 and 17-3 are used 
to detect the rank of the sensor. In the illustrated example, the ranking 
pattern portions connected to the patterns 17-2 and 17-3 are bored, thus 
forming the open circuits regarding the patterns 17-2 and 17-3. The 
pattern portion connected to the pattern 17-1 is not bored or cut so that 
the voltage in this pattern is maintained at the earth voltage. 
By comparing the head having the so cut pattern with a corresponding table 
such as shown in FIG. 9, it can be judged that the head is included in the 
rank 4 (i.e., the sensor has the dispersion of 0.560 to 0.565 at a room 
temperature). 
The recording factor setting means reads the rank of the head whenever a 
power source of the main body of the recording system is turned on, and 
three-bit information read is stored in a RAM in place. The three-bit 
information stored in the RAM can be read by the CPU. 
In this way, on the basis of the temperature information read, the current 
value to be supplied is determined, and such current is supplied to the 
heating member 130. 
FIG. 13 is a schematic view of a recording system for explaining the 
above-mentioned control system, where the reference numeral P denotes a 
platen for feeding a recording medium; CU denotes a control circuit 
including a sensor rank judging circuit, record factor setting circuit, 
heat signal generating circuit, drive signal generating circuit, carriage 
driving circuit and CPU; and H denotes a head having an ink tank and 
removably mounted on the recording system. 
As to the heat control, in place of the heating heater 130, the ink 
discharging electrical/thermal converting elements 110 may be energized at 
a level which does not discharge the ink. Of course, both the heating 
heater 130 and the electrical/thermal converting elements 110 may be Iused 
altogether. The controls of these elements are effected through a heat 
signal from the heat signal generating circuit on the basis of the 
parameters set by the record factor setting circuit. Further, when the 
driving condition for the ink discharge is changed, such change is 
effected through a drive signal from the drive signal generating circuit 
under the same process. 
Incidentally, in the illustrated example, while the three-bit ranking into 
eight ranks was explained, the ranking is not limited to this three-bit 
into eight ranks, but may comprise four-bit into 16 ranks, five-bit into 
32 ranks, two-bit into four ranks or the like, in accordance with the 
degree of the dispersion. 
As apparent from the above, according to this example, since the dispersion 
of the voltage reduction V.sub.F in the normal direction of the 
temperature sensors comprising the diodes integrally formed on the head 
can be judged by ranking the sensors, it is possible to perform the fine 
and correct control according to the dispersion. Further, since the 
pattern portions on the PCB plate are merely cut, the setting can be done 
easily and the image quality can be improved. 
Next, the substrate for the recording head will be explained. 
FIG. 11 is a schematic sectional view of the substrate 14 taken along the 
line A-A' of FIG. 8. 
The reference numeral 200 denotes a P-type semiconductor plate made of a 
single crystal silicone material; 201 denotes an N-type semiconductor 
embedded layer; 202 and 202' denote P-type semiconductor separating areas; 
203 denotes an N-type semiconductor epitaxial growth area; 204 denotes a 
P-type semiconductor base area; and 205 denotes an N-type semiconductor 
emitter area. The collector area is constituted by the N-type 
semiconductor areas 203', 201 and 206. Base-collector common electrodes 
301 made of aluminium material and electrodes 302 are electrically 
connected through ohmic contact areas 207, 208 and 209 of high impurity 
density material. 
In the recording head substrate having the above-mentioned construction, by 
forming the emitter area 205 acting as the diffusion layer slightly, the 
side extension of the diffusion layer can be suppressed, whereby it is 
possible to attain the high integration without worsening the pressure 
endurance and to reduce the diffusing ability between the emitter area 205 
and the base area 204. In order to use such substrate as the recording 
head, the process for forming the electrical/thermal converting elements 
on the substrate is added. This process includes a step of electrically 
connecting between the electrical/thermal converting elements and the 
functional elements. 
Now, an N-P-N transistor is formed, and the areas 206, 208 completely 
enclose the emitter area 205 and the base area 204. Further, each cell is 
electrically isolated by the element separating areas enclosing these 
areas and the separating areas 202, 202'. 
In this way, by using the N-P-N transistor having the short-circuited base 
and collector as a diode, the temperature feature thereof is improved. 
On the recording head 100 according to this embodiment, a heat accumulating 
layer 102 comprising an SiO.sub.2 film is formed, by a PCVD method or a 
sputtering method, on a heat-oxidized SiO.sub.2 film 101 on the substrate 
having the above-mentioned driving portions, and thereon, the 
electrical/thermal converting elements comprising an HfB.sub.2 heat 
resistance layer 103 obtained by the sputtering method and aluminium 
electrodes 104, 104' obtained by the sputtering method are formed. 
Further, on the heating portions 110 of the electrical/thermal converting 
elements, an SiO.sub.2 protection film 105 obtained by the sputtering 
method, and a Ta protection film 106 for preventing the canitation are 
formed. 
Now, the SiO.sub.2 film forming the heat accumulation layer 102 is formed 
integrally with insulation films between the wirings 301, 302 and 303. 
With the arrangement obtained by the transistor having the short-circuited 
base and collector as shown in FIGS. 6 and 7, since the building-up 
feature thereof is excellent and the parasitic effect is relatively low, 
the dispersion between the elements can be further reduced. Further, by 
earthing the isolation electrodes 302, it is possible to prevent the 
electric charge from flowing into the adjacent cell, thus preventing the 
erroneous operation of the other elements. 
The recording head is completed by attaching the top plate made of glass or 
resin material and adapted to constitute the ink discharging portion 
having the ink discharge opening for discharging for example the ink, to 
the substrate having the electrical/thermal converting elements and the 
functional elements operated as mentioned above. 
Next, a manufacturing process for the substrate according to this 
embodiment will be explained. 
(1) A silicon dioxidation film having a thickness of about 5000-20000 .ANG. 
is formed on a surface of the P-type silicon substrate having the impurity 
density of about 1.times.10.sup.12 -10.sup.16 cm.sup.-3. 
(2) The portion of the silicon oxidation film where the collector embedding 
area 201 of each cell is formed is removed by photo-lithography treatment. 
(3) After a thin silicon oxidation film is formed, the N-type collector 
embedding area 201 having the impurity density of 1.times.10.sup.19 
cm.sup.-3 or more is formed by 10-20 .mu.m through heat diffusion by 
ion-pouring the N-type impurity such as P, As and the like into the film. 
In this case, the sheet resistance was selected to have a low value of 30 
.OMEGA./.quadrature. or less. 
(4) Then, the portions of the oxidation film where the P-type isolation 
areas 202 should be formed are removed, and after a thin oxidation film 
having the thickness of about 100-3000 .ANG. is formed, the P-type 
isolation areas 202 having the impurity density of 1.times.10.sup.17 
-10.sup.19 cm.sup.-3 are formed through the heat diffusion by ion-pouring 
the P-type impurity such as B into the film. 
(5) After the oxidation films are removed from the whole surface, the 
N-type epitaxial area 203 having the impurity density of about 
1.times.10.sup.12 -10.sup.16 cm.sup.-3 is epitaxial-grown by about 5-20 
.mu.m (see FIG. 12A). 
(6) Next, a silicon oxidation film having a thickness of about 100-300 
.ANG. is formed on a surface of the N-type epitaxial area, the resist is 
painted, the patterning is effected, and the P-type impurity is ion-poured 
into only an area where the low density base area 204 should be formed. 
After the resist is removed, the low density P-type base area 204 having 
the impurity density of 5.times.10.sup.14 -5.times.10.sup.17 cm.sup.-3 is 
formed by 5-10 .mu.m. 
(7) After the oxidation film is removed from the whole surface and a new 
silicon oxidation film having a thickness of 1000-10000 .ANG. is formed, 
the portions of the film where the P-type isolation areas 202' should be 
formed are removed, and a BSG film is coated on the whole surface by using 
the CVD method, and further, the P-type isolation areas 202' having the 
impurity density of 1.times.10.sup.18 -10.sup.20 cm.sup.-3 are formed, 
through the heat diffusion, by about 10 .mu.m to reach the P-type 
isolation areas 202. The isolation areas 202' may be made of BBr.sub.3 
through the heat diffusion. 
(8) After the BSG film is removed, a silicon oxidation film having a 
thickness of about 1000-10000 .ANG. is formed, and then, after the portion 
of the film where the collector area 206 should be formed is removed, P 
ion is poured by forming PSG and the N-type collector area 206 is formed, 
through heat diffusion, to reach the collector embedding area 201. In this 
case, the sheet resistance was selected to have a low value of 10 
.OMEGA./.quadrature. or less, and the impurity density was selected to 
have a value of 1.times.10.sup.18 -10.sup.20 cm.sup.-3 (see FIG. 12B). 
(9) Subsequently, after the oxidation film is removed from the cell areas, 
a silicon oxidation film having a thickness of 100-300 .ANG. is formed, 
the resist patterning is. performed, and the P-type impurity is ion-poured 
into only areas where the high density base area 209 and the high density 
isolation area 207 should be formed. After the resist is removed, the 
portions of the oxidation film where the N-type emitter area 205 and the 
high density N-type collector area 208 should be formed are removed, and 
then, a PSB film is formed on the whole surface. After the ion N.sup.+ is 
poured, the high density P-type base area 209, high density P-type 
isolation area 207, N-type emitter area 205 and high density N-type 
collector area 208 are simultaneously formed through the heat diffusion. 
Incidentally, the thickness of each area was selected to have a value of 
1.0 .mu.m or less, and the impurity density was selected to have a value 
of 1.times.10.sup.19 -10.sup.20 cm.sup.-3 (see FIG. 12C). (10) Further, 
after the silicon oxidation film is partially removed from areas for 
connection to the electrodes, aluminium material is coated on the whole 
surface, and the aluminium material is removed from the area for 
electrical connection. And, the SiO.sub.2 film 102 forming the heat 
accumulating layer and the insulation film between the layers 102 is 
formed on the whole surface by about 0.4-1.0 .mu.m through the spattering 
method. The SiO.sub.2 film may be formed by the CVD method. 
Then, HfB.sub.2 material is coated by a thickness of about 1000 .ANG. to 
form the heat resistance layer 103. An aluminium layer is coated on this 
layer 103 and is patterned to simultaneously form the pair of electrodes 
104, 104' of the electrical/thermal converting elements, anode electrode 
wiring (not shown) and cathode wiring (not shown) of the diodes, and the 
electric connections therefor. 
Thereafter, the SiO.sub.2 layer 105 acting as the protection layer for the 
electrical/thermal converting elements and the insulation layers between 
the aluminium layer wirings is deposited by the sputtering method, and Ta 
material is deposited on the heating portions of the electrical/thermal 
converting elements by a thickness of about 2000 .ANG. to form the 
anti-canitation protection layer 106. In this way, the substrate as shown 
in FIG. 6 is obtained. 
Next, each of and the relationship between an ink jet unit IJU, ink jet 
head IJH, ink tank IT, ink jet cartridge IJC, ink jet recording system 
body IJRA and carriage HC to which the present invention is preferably 
applied will be fully described with reference to FIGS. 14 to 18. 
As apparent from FIG. 15 showing a perspective view of the ink jet 
cartridge, the ink jet cartridge IJC in this embodiment has a large ink 
containing ability and has a configuration that the front end of the ink 
jet unit IJU slightly protrude beyond the front face of the ink tank IT. 
The ink jet cartridge IJC can be fixedly supported by a positioning means 
and electrical contacts (described later) of the carriage HC (FIG. 17) 
mounted on the ink jet recording system IJRA and is of a non-returnable or 
disposable type which can be removably mounted on the carriage HC. 
In the illustrated embodiment shown in FIGS. 14 to 18, since the 
construction includes various inventions created before the present 
invention was completed, the whole construction will be fully explained 
while describing such construction briefly. 
(i) Construction of the Ink Jet Unit IJU 
The ink jet unit IJU is a bubble jet type unit which performs the recording 
by utilizing the electrical/thermal converting elements for generating 
thermal energy adapted to create the film boiling into the ink in response 
to an electric signal. 
In FIG. 14, the reference numeral 14 denotes a heater board on which a 
plurality of rows of electrical/thermal converting elements (discharging 
heaters) disposed on an Si substrate and aluminium electrical wiring for 
supplying the electric power to the elements are formed by the film 
forming technique. The reference numeral 12 denotes a wiring substrate 
corresponding to the heater board 14 and including wirings corresponding 
to those of the heater board 14 (which are connected to each other by the 
wire bonding) and patterns 12-1 arranged at the ends of the wirings for 
receiving the electric signals from the recording system. 
The reference numeral 1300 denotes a top plate with recesses having 
partition walls for separating a plurality of ink passages independently 
and a common liquid chamber, which top plate integrally includes an ink 
receiving port 1500 for receiving the ink supplied from the ink tank and 
for introducing the ink into the common liquid chamber, and an orifice 
plate 400 having a plurality of ink discharge openings. While material of 
the top plate is preferably polysulfone, but other moulding resin material 
may be used. 
The reference numeral 11 denotes a support (for example made of metal) for 
flatly supporting the back surface of the wiring substrate 12, which 
support 11 forms a bottom plate of the ink jet unit. The reference numeral 
500 denotes an M-shaped leaf spring which urges the common liquid chamber 
at its central portion and urges a portion of the liquid passages with a 
line contact by a front bent portion 501 formed on the spring. The heater 
board 14 and the top plate 1300 are engaged by each other by engaging a 
foot of the leaf spring 500 extending through a hole 3121 of the support 
11 with the back surface of the support 11, and the heater board 14 is 
firmly fixed to the top plate 1300 by the biasing force of the leaf spring 
500 and its front bent portion 501. The support 11 has positioning holes 
312, 1900, 2000 engaged by two positioning projections 1012 and 
positioning and heat fusing retaining projections 1800, 1801 formed on the 
ink tank IT and is further provided at its back surface with positioning 
projections 2500, 2600 for the carriage HC of the ink jet recording system 
IJRA. In addition, the support 11 has a hole 320 through which an ink 
supply tube 2200 (described later) for permitting the ink supply from the 
ink tank. The wiring substrate 12 is attached to the support 11 by an 
adhesive. 
Incidentally, recesses 2400 are formed in the support 11 near the 
positioning projections 2500, 2600, respectively, and are positioned so 
that, when the ink jet cartridge IJC is assembled (see FIG. 15), the 
recesses are situated on the extension points of a head front area 
constituted by a plurality of parallel grooves 3000, 3001 at three sides 
of the head, thus preventing the foreign matter such as dust, ink and the 
like from reaching the positioning projections 2500, 2600. 
As seen from FIG. 17, a lid member 800 having the parallel grooves 3000 
forms an outer wall of the ink jet cartridge IJC and defines a space for 
receiving the ink jet unit IJU. Further, an ink supply member 600 having 
the parallel grooves 3001 has an ink supply conduit 1600 communicating 
with the ink supply tube 2200, which ink supply conduit is fixedly 
supported at the ink supply tube 2200 side in a cantilever fashion. And, 
in order to ensure the capillary phenomenon between the ink supply conduit 
fixing side and the ink supply tube 2200, a seal pin 602 is inserted. 
Incidentally, the reference numeral 601 denotes a packing for providing a 
connection seal between the ink tank IT and the ink supply tube 2200; and 
700 denotes a filter disposed at an end of the ink supply tube near the 
ink tank. 
Since the ink supply member 600 is formed in the moulding operation, it can 
be manufactured at a low cost and with high accuracy, and, even when the 
ink jet units are manufactured in mass-production, the cantilevered ink 
supply conduit 1600 of the ink supply member can stably be pressed against 
the ink receiving port 1500. In the illustrated embodiment, the perfect 
communication can be positively obtained merely by applying any sealing 
adhesive to the pressed contacting portion between the port 1500 and the 
conduit 1600 from the ink supply member side. 
Incidentally, the ink supply member 600 is fixedly attached to the support 
11 by protruding pins (not shown) formed on the back surface of the ink 
supply member 600 through holes 1901, 1902 formed in the support 11 and 
then by fusing the protruding ends of the pins onto the back surface of 
the support 11 by heat. Since such heat-fused and slightly protruding 
portions on the back side of the support 11 can be received in recesses 
(not shown) formed in a surface of the ink tank IT to which the ink jet 
unit IJU are to be attached, the ink jet unit IJU can be correctly 
positioned. 
(ii) Construction of the Ink Tank IT The ink tank comprises a cartridge 
body 1000, an ink absorber 900, and a lid member 1100 for sealingly 
closing the cartridge body 1000 after the ink absorber 900 is inserted 
into the cartridge body from a side opposite to the side to which the unit 
IJU is attached. 
The ink absorber 900 is arranged in the cartridge body 1000 for holding the 
ink therein. The reference numeral 1200 denotes a supply port for 
supplying the ink to the unit ICU comprising the above-mentioned elements 
100-600. This port 1200 also serves as a pouring port for impregnating the 
ink into the ink absorber 900 by pouring the ink from this port before the 
ink jet unit IJU is installed on a portion 1010 of the cartridge body 
1000. 
In the illustrated embodiment, the portion through which the ink can be 
supplied include, an atmosphere vent opening 1401 and this supply port 
1200. In order to improve the ink supply from the ink absorber, an air 
space or area in the tank defined by ribs 2300 of the cartridge body 1000 
and partial ribs 2301, 2302 of the lid member 1100 is communicated with 
the atmosphere vent opening 1401 and is formed in a corner area remote 
from the supply port 1200. Thus, relatively good and uniform supply of the 
ink to the ink absorber can be effected through the supply port 1200. This 
is very effective in practical use. The ribs 2300 comprise four ribs 
arranged on the surface of the cartridge body 1000 at its rear portion and 
extending parallel to a carriage moving direction, so that the ink 
absorber is prevented from being closely contacted with the rear surface. 
Similarly, the partial ribs 2301, 2302 are formed on the inner surface of 
the lid member 1100 on extension lines of the ribs 2300, but, unlike to 
the ribs 2300, the partial ribs are divided into plural pieces to increase 
the air existing space than the ribs 2300. Incidentally, the partial ribs 
2301, 2302 are distributed on an area smaller than a half of the whole 
surface area of the lid member 1100. 
With these ribs, it is possible to positively direct the ink in the ink 
absorber at the corner area remote from the supply port 1200 by the 
capillary action toward the supply port 1200 with a more stable condition. 
The reference numeral 1401 denotes the aforementioned atmosphere vent 
opening formed in the lid member for communicating the interior of the 
cartridge with the atmosphere; and 1400 denotes a liquid anti-flow member 
arranged in the atmosphere vent opening 1400 for preventing the ink from 
leaking through the opening 1401. 
The ink containing space in the ink tank IT has a parallelepipedal shape, 
and the longer side surfaces thereof correspond to the side wall of the 
tank. Thus, the above-mentioned rib arrangement is particularly effective. 
However, the longer side surfaces are parallel to the carriage moving 
direction or the ink containing space has a cubic shape, the ink supply 
from the ink absorber 900 can be stabilized by arranging the ribs on the 
whole surface of the lid 1100. 
Further, the construction of the attachment surface of the ink tank IT to 
the ink jet unit IJU is shown in FIG. 16. 
When a straight line passing through centers of the discharge openings of 
the orifice plate 400 and extending parallel to a mounting reference face 
provided on the bottom surface of the tank IT or the top surface of the 
carriage is designated by L.sub.1, the two positioning projections 1012 
adapted to be engaged by the positioning holes 312 formed in the support 
11 are disposed on this straight line L.sub.1. The height of each 
positioning projection 1012 is slightly smaller than a thickness of the 
support 11, these projections being used to position the support 11. In 
FIG. 16, on the straight line Li, there is also disposed a pawl 2100 
adapted to be engaged by an engagement surface 4002 of a bent portion of a 
carriage positioning hook 4001, so that the force for positioning the 
carriage acts in a surface area parallel to the above-mentioned reference 
face including the straight line L.sub.1 (FIG. 17). Such relationship is 
effective since the positioning accuracy for only the ink tank equals to 
the positioning accuracy for the discharge openings of the head (The 
details will be described later with reference to FIG. 17). 
Further, projections 1800, 1801 of the ink tank corresponding to holes 
1900, 2000 of the support 11 (through-which the ink tank is fixed to the 
support) are longer than the aforementioned projections 1012, so that the 
portions of the projections protruded from the support 11 can be fused by 
heat to be fixed to the surface of the support. When a straight line 
perpendicular to the straight line L.sub.1 and passing through the 
projection 1800 is designated by L.sub.3 and a straight line perpendicular 
to the line L.sub.1 and passing through the projection 1801 is designated 
by L.sub.2, since the center of the supply port 1200 is situated 
substantially on the straight line L.sub.3, the connecting condition 
between the supply port 1200 and the ink supply tube 2200 is stabilized, 
and, if the system is dropped or is subjected to any shock, the load 
acting on such connecting condition can be reduced. Incidentally, since 
the straight line L.sub.2 is not aligned with the straight line L.sub.3 
and the projections 1800, 1801 are situated around the projection 1012 of 
the ink jet head IJH, the positioning of the head IJH to the ink tank IT 
is further ensured and reinforced. 
Incidentally, a curve shown by L.sub.4 indicates a position of an outer 
wall of the ink supply member 600 when installed. Since the projections 
1800, 1801 are situated along the curve L.sub.4, the sufficient strength 
and positional accuracy are provided by these projections, regardless of 
the weight of the front end portion of the head IJH. Incidentally, the 
reference numeral 2700 denotes a front tab of the ink tank IT adapted to 
be inserted into a hole formed in a front plate 4000 of the carriage. The 
reference numeral 2101 denotes an engagement tab for engaging by a further 
engagement portion of the carriage HC. 
Since the ink tank IT is covered by a lid or cap 800 after the ink jet unit 
IJU is mounted on the ink tank, the ink jet unit IJU is enclosed except at 
its lower opening. However, in the ink jet cartridge IJC, since the lower 
opening thereof is situated closely adjacent to the carriage HC when it is 
mounted on the carriage, the ink jet cartridge will be enclosed 
substantially at all sides thereof. 
Thus, the heat generated from the ink jet head IJH disposed in this 
enclosed space is effective to maintain a certain temperature in this 
space. 
However, when the recording system is continuously operated for a long 
time, the temperature in this space is increased. 
To avoid this, in the illustrated embodiment, in order to assist the 
natural heat dispersion, a slit 1700 having a width smaller than that of 
the aforementioned space is formed in the upper surface of the cartridge 
IJC so that the increase in temperature in the space is prevented and the 
uniformity of the temperature distribution in the whole ink jet unit IJU 
is maintained regardless of the change in the environmental condition. 
When the ink jet cartridge IJC is assembled, the ink is supplied to the 
supply tank 600 through the supply port 1200, hole 320 formed in the 
support 11 and an introduction opening formed in the back surface of the 
supply tank 600 at its central position. After flowing in the supply tank, 
the ink then flows into the common liquid chamber through an outlet 
opening formed in the tank, an appropriate supply tube and an ink 
introduction opening 1500 of the top plate 1300. At conjunction portion in 
such ink flowing path, any packings made of, for example, silicon rubber, 
butyl rubber and the like are arranged to ensure the sealing thereof and 
to keep the ink flowing path without leakage. 
Incidentally, in the illustrated embodiment, the top plate 1300 is made of 
resin material having a good anti-ink property (not deteriorated by the 
ink) such as polysulfone, polyethersulfone, polyphenylene oxide, 
polypropylene and the like, and is moulded integrally simultaneously with 
the orifice plate 400 in a mould. 
As mentioned above, since the ink supply member 600, top plate 1300 and 
orifice plate 400, and the ink tank body 1000 are formed as integral 
parts, respectively, the assembling accuracy is increased and the quality 
of the product is also improved even if it is manufactured in the 
massproduction line. Further, since the number of parts is reduced in 
comparison with the conventional manufacturing process, it is possible to 
obtain the desired features positively and easily. 
(iii) Attachment of Ink Jet Cartridge IJC to Carriage HC 
In FIG. 17, the reference numeral 5000 denotes a platen roller for guiding 
a recording medium from a downward to a upward direction. The carriage HC 
can be shifted along the platen roller 5000. On the front side of the 
carriage facing the platen roller, the front plate 4000 (having a 
thickness of 2 mm) disposed on the front side of the ink jet cartridge 
IJC, an electric connection portion supporting plate 4003 for holding a 
flexible sheet 4005 provided with patterns 2011 corresponding to the 
patterns 12-1 of the wiring substrate 12 of the cartridge IJC and a rubber 
pad 4006 for generating an elastic force for urging the flexible sheet 
from its back in coincidence with the patterns 2011, and a positioning 
hook 4001 for fixing the ink jet cartridge IJC in a recording position are 
arranged. 
The front plate 4000 has a positioning projecting surfaces 4010 in 
correspondence with the aforementioned positioning projections 2500, 2600 
of the support 11 of the cartridge, and is subjected to a vertical force 
directing toward the projecting surfaces 4010 after the carriage is 
mounted. Thus, on the front plate facing the platen roller, a plurality of 
reinforcement ribs (not shown) are provided in the direction of the 
vertical force. These ribs also form a head protection protruding portion 
protruding toward the platen roller slightly (about 0.1 mm) from a front 
surface position L.sub.5 when the cartridge is mounted. 
The electric connection portion supporting plate 4003 has a plurality of 
reinforcement ribs 4004 disposed in a direction perpendicular to the 
aforementioned ribs and the degree of the projection of these ribs 4004 is 
gradually decreased from the platen roller to the hook 4001. Thus, the 
position of the cartridge when mounted is inclined as shown in FIG. 17. 
Further, the supporting plate 4003 has a positioning face 4008 facing the 
platen roller, and a positioning face 4007 facing the hook to stabilize 
the electrical contact condition. Between these faces, a pattern contact 
area is formed, and the supporting plate defines an amount of the 
deformation of a ridge rubber sheet 4006 corresponding to the pattern 
2011. These positioning faces abut against the surface of the wiring 
substrate 12 when the cartridge is mounted in a recordable position. In 
the illustrated embodiment, since the patterns 12-1 of the wiring 
substrate 12 are arranged symmetrically with respect to the aforementioned 
straight line L.sub.1, the amounts of the deformation of the ridges of the 
rubber sheet 4006 are uniform to more stabilize the contacting pressure 
between the pats 2011 and 12-1. In the illustrated embodiment, the 
patterns 12-1 are arranged in two upper and lower rows and in two lines. 
In FIG. 14, while the patterns 12-1 were merely schematically shown for 
illustrating the other construction with detail, it should be noted that 
these patterns 12-1 have the aforementioned ranking patterns 17 and the 
patterns 2011 have a corresponding construction for reading the ranking 
patterns. 
The hook 4001 has a slot engaged by a fixed shaft 4009. By using the lost 
motion of the slot, after the hook is rotated in an anti-clockwise 
direction from a position shown in FIG. 17, by shifting the hook in the 
left direction along the platen roller 5000, the ink jet cartridge IJC 
can-be positioned with respect to the carriage HC. While the hook 4001 can 
be shifted in any manner, but preferably the movement of the hook is 
effected by a lever arrangement and the like. In any case, during the 
rotation of the hook 4001, while the cartridge IJC is shifted toward the 
platen roller, the positioning projections 2500, 2600 are shifted to a 
position where they can be abutted against the positioning faces 4010. 
Consequently, by shifting the hook 4001 to the left, the engagement 
surface 4002 of the bent portion of the hook engages by the pawl 2100 of 
the cartridge IJC. Then, by rotating the cartridge IJC in a horizontal 
plane around the contacting area between the positioning faces 2500 and 
4010, the patterns 12-1 are eventually brought in contact with the 
patterns 2011. And, when the hook 4001 is held in a predetermined position 
or fixed position, the perfect contact between the patterns 12-1 and 2011, 
the perfect contact between the positioning faces 2500 and 4010, the 
contact between the engagement surface 4002 and the pawl 2100, and the 
contact between the wiring substrate 12 and the positioning surfaces 4007, 
4008 are simultaneously attained, thus completing the holding of the 
cartridge IJC with respect to the carriage. 
(iv) Summary of Ink Jet Recording System Body 
FIG. 18 schematically shows an ink jet. recording system embodying the 
present invention. In the ink jet recording system, the carriage HC has is 
a pin (not shown) engaged by a spiral groove 5004 formed in a lead screw 
5005 rotated through driving force transmitting gears 5011, 5009 in 
response to the normal rotation of a driving motor 5013, s0 that the 
carriage can be reciprocably shifted in directions shown by the arrows a 
and b. A sheet holder 5002 urges a sheet (recording medium) against the 
platen roller 5000 through the moving direction of the carriage. 
Home position detecting means 5007, 5008 detect the presence of a lever 
5006 of the carriage by their photo couplers to control the switching of 
the rotational direction of the driving motor 5013. A supporting member 
5016 supports a cap member 5022 covering the front surface of the 
recording head, and an absorbing means 5015 performs the absorbing 
recovery of the recording head through an opening 5023 formed in the cap 
member. A support member 5019 supports a cleaning blade 5017 for movement 
in a fore and aft direction, and these are supported by a support plate 
5018 of the body. It should be noted that the cleaning blade is not 
limited to the illustrated configuration, but may be any conventional one. 
Further, a lever 5021 for initiating the suction for the absorbing 
recovery is shifted in synchronous with the movement of a cam 5020 engaged 
by the carriage, and the movement of the lever can be controlled by the 
driving force from the driving motor through a conventional transmitting 
means such as a clutch and the like. 
In the illustrated embodiment, while the capping, cleaning and absorbing 
recovery operations are performed by the action of the lead screw 5005 
when the carriage reaches the home position, these operations may be 
effected at well-known timings. The above-mentioned constructions or 
arrangements are excellent when used independently or in combination, and 
are preferable ones for use in the present invention. 
An example of the most characteristic circuit among these drive control 
systems was shown in FIG. 13. Now, the relationship between FIG. 13 and 
FIG. 10 will be described. In FIG. 13, the sensor rank judging circuit 
reads out the rank data on a data line electrically connected to the 
patterns 17-1, 17-2 and 17-3 on the basis of the timing controlled by the 
CPU through a noise preventing shunt circuit (not shown). The resistors 
shown in FIG. 10 are pull-up resistors which can keep the line voltage at 
a constant value (for example, +5 volts) when the line of the pattern is 
opened. 
Embodiment 2 
FIG. 19 shows an example of a color ink jet recording system of a so-called 
bubble jet type having the electrical/thermal converting elements as an 
energy generating means, embodying the present invention. 
In FIG. 19, a recording medium 401 such as a paper or a plastic sheet is 
supported by two pair of feeding rollers 402, 403 arranged on both upper 
and lower sides of a recording area, and is fed in a direction shown by 
the arrow A by means of the feeding rollers 402 driven by a sheet feeding 
motor 404. Ahead of the feeding rollers 402, 403, a guide shaft 405 is 
arranged in parallel to these rollers. A carriage 406 is shifted along the 
guide shaft 405 by the output of a carriage motor 407 through a wire 408 
in a direction shown by the arrow B. 
An ink jet recording head unit 490 of the bubble jet type is mounted on the 
carriage 406. The recording head unit 490 can form a color image and is 
arranged in a scanning direction, and includes four recording heads 409A, 
409B, 409C and 409D corresponding to cyan (C) ink, magenta (M) ink, yellow 
(Y) ink and black (BK) ink, respectively. On a front surface of each 
recording head 409, i.e., on a surface facing the recording medium 401 
with a predetermined distance (for example, 0.8 mm), a recording portion 
having a plurality (for example, 64, 128, 256) of ink discharge openings 
arranged in line is provided. 
More particularly, on the surface facing the recording medium 401, a 
plurality of ink discharge openings 410 arranged in a vertical direction 
at a predetermined interval are formed. By generating the bubble 411A in 
the ink by energizing the electrical/thermal converting element (heat 
resistor and the like) 411 associated with each discharge opening 410, an 
ink droplet is flies from the corresponding discharge opening due to the 
pressure created by the bubble. In this way, by transferring the ink 
droplets onto the recording medium 401 at a predetermined pattern, a 
desired recording is effected. 
On each recording head 409, a circuit substrate of a driving circuit 
(driver) 429 for performing the driving as mentioned above is mounted. 
A control portion including a control circuit (CPU), ROM and RAM provided 
in the CPU and the like is formed on a control substrate 415, and this 
control portion receives a command signal and a data signal from a host 
device 414 such as a computer and applies the driving voltage (heat 
voltage) of the electrical/thermal converting element to each recording 
head 409A-409D through a heat driver 413 and driving sources for various 
motors, on the basis of the received signal. 
An operation panel 560 attached to an outer casing (not shown) of the 
recording system comprises a key setting portion including an 
on-line/off-line changing key 416A, a line feed key 416B, a form feed key 
416C, and a record mode changing key 416D, and a display portion including 
a plurality of alarm lamps 416E and a warning lamp 416F such as a power 
source lamp. 
FIG. 20 shows an example of a head chip arranged in each recording head 
according to this embodiment. A heater board 441 comprises a silicon 
substrate on which electrical/thermal converting elements (discharging 
heaters) 445 and aluminium wirings 446 for supplying electric power to the 
discharging heaters are formed by the film forming technique. The head 
chip is completed by adhering a top plate 430 having partition walls for 
defining recording liquid passages 425 to the heater board 441. 
The recording liquid (ink) is supplied to a common liquid chamber 423 
through a supply port 424 formed in the top plate 430, and then is 
introduced into each nozzle 425. When the heater 445 is heated by 
energizing it, the bubble is created in the ink filled in the nozzle 425, 
thereby discharging the ink droplet from the discharge opening 426. 
FIGS. 21A and 21B are a plan view and an enlarged view respectively of the 
heater board according to this embodiment. 
In FIG. 21A, the reference numeral 443 denotes a discharging heater 
portion. Terminals 444 are connected to any external equipments through 
the wire bonding. Temperature sensors 442 acting as temperature detecting 
means are formed on the discharging heater portion 443 by the film forming 
technique as same as that used in the formation of the discharging heater 
portion. FIG. 21B shows a portion B including the sensor 442 of FIG. 21A 
in an enlarged scale. The reference numeral 448 denotes a lagging or heat 
keeping heater acting as a heating means. 
Since the sensors 442 are formed by the film forming technique like the 
other elements, they have very high accuracy, and they can be made of 
material having the conductivity varying in accordance with the 
temperature, such as aluminium, titanium, tantalum, tantalum pentoxide, 
niobium and the like. For example, among these materials, aluminium is a 
material which can be used to form the electrodes, titanium is a material 
which can be disposed between the heat resistance layer constituting the 
electrical/thermal converting element and the electrode to enhance the 
adhesion ability therebetween, and tantalum is a material which can be 
disposed on the protection layer on the heat resistance layer to enhance 
the anti-canitation ability of the protection layer. Further, in order to 
reduce the dispersion in the processes, the width of the wiring is 
increased, and, in order to reduce the influence from the wiring 
resistance, the wirings are arranged in a zigzag fashion, thereby 
providing high resistance. 
Incidentally, the sensor 442 may be constituted by a diode to effectively 
utilize the feature of the diode that the voltage in the normal direction 
of the diode (i.e., diode forward voltage) is changed in response to the 
temperature. FIG. 21C shows the temperature feature of the diode. 
The heat keeping heater 448 can be made of material (for example, 
HfB.sub.2) the same as that of the heat resistance layer of the 
discharging heater 405, but may be made of other material constituting the 
heater board, such as aluminium, tantalum, titanium and the like. 
Next, a mode of the temperature control for the recording head according to 
this embodiment will be explained. 
In the recording head shown in FIG. 20 according to this embodiment, as 
shown in FIG. 21, since the temperature sensors 442 are arranged on both 
sides of the heater board 441,. the temperature distribution on the 
substrate in the direction of the array of the nozzles 425 can be known 
from the outputs of the temperature sensors. Further, since the heat 
keeping heaters 448 are arranged in the vicinity of the temperature 
sensors 442, the temperature detection is swiftly responsive to the change 
in temperature due to the heating. By using this feature, the control for 
keeping the temperature distribution on the substrate at a given value can 
be performed with high response and high stability. 
FIG. 22 schematically shows a control system for the ink jet recording 
system of FIG. 19. The reference numeral 415A denotes a record controlling 
portion disposed on the control substrate 415 and adapted to perform the 
recording operation while effecting the control for various portions of 
the recording system; and 415B denotes an interface portion for sending 
and receiving various signals between it and the outside host device. The 
record controlling portion 415A may be in the form of a microcomputer 
comprising a CPU for performing the control operation, a ROM storing a 
program including the control sequencer a RAM having a recording data 
developing area and a working area, and the like. Further, in the 
illustrated embodiment, a central portion of an environmental condition 
measuring apparatus (described later with reference to FIG. 23) is 
integrally incorporated in the recording system. 
FIG. 23 shows an example that a temperature adjusting apparatus is 
integrally incorporated into the record controlling portion. 
The reference numerals D1-D4 denote temperature sensors 402 (in this 
example, diodes) disposed on the recording heads 409A-409D; 451 denotes 
amplifiers each having a constant current circuit; 452 denotes an analogue 
switch which can select one of the outputs of the amplifiers 451 on the 
basis of control signals A, B; and 453 denotes an amplifier for receiving 
the output of the analogue switch. 
The reference numeral 454A denotes a CPU constituting a main controlling 
portion of the recording system according to this example and adapted to 
perform the correction data storing operation and the measuring operation 
in accordance with a predetermined sequence which will be described later 
with reference to FIGS. 24 and 26; 454B denotes a ROM for storing the 
program including such sequence and other given data; and 454C denotes a 
RAM having a data developing area and a working area. The reference 
numeral 455 denotes a nonvolatile memory, for example, in the form of 
EEPROM; 460-463 denote heat keeping heaters (448) arranged on the heater 
boards of the recording heads 409A 409D; and 456-459 denote drivers for 
the heat keeping heaters. 
Incidentally, in FIG. 23, while one diode as the temperature sensor was 
shown for each recording head, of course, as the example shown in FIG. 21, 
two diodes may be used for each recording head. Even if the number of the 
detecting sensors (diodes) is increased as such, this embodiment can 
effectively cope with such increase of the sensors, as apparent from the 
following description. 
In the illustrated embodiment, the diodes are used as the temperature 
sensors, and the temperature is detected by the use of the temperature 
feature of the diode forward voltage reduction V.sub.F. The amplifiers 451 
are the constant current circuits, and thus, the constant current 
i=E.sub.1 /R.sub.1 flows in the diode. Of course, to arrange or adjust the 
conditions, the following equation should be met: R.sub.1 =R.sub.2 
=R.sub.3 =R.sub.4. The output selected by the analogue switch 452 on the 
basis of the control signals A, B is compared with the reference voltage 
in the amplifier 453, and the voltage difference is multiplied by R.sub.6 
/R.sub.5 to obtain the output of the amplifier 453. That is to say, the 
output V0 of the amplifier 453 can be expressed by the following equation: 
##EQU1## 
(where, C.sub.0 =E.sub.2 -(E.sub.1 -E.sub.2).multidot.(R.sub.6 /R.sub.5); 
A=-(R.sub.6 /R.sub.5)). Thus, it is found that the output V0 is a function 
of the voltage V.sub.F of the temperature sensor. 
However, in effect, the amplifiers 451, 453 are not ideal amplifiers and 
include input offset voltages and the like, and thus, the influence of 
these amplifiers upon the final output V0 cannot be negligible. Now, when 
the input offset voltage of the amplifier 451 is V.sub.1 and the input 
offset voltage of the amplifier 453 is V.sub.2, the equation (1) is 
rewritten to: 
##EQU2## 
(where, C.sub.1 =C.sub.0 +V.sub.2 A(V.sub.2 -V.sub.1)). Thus, the output 
V.sub.0 is influenced upon the offset voltages V.sub.1, V.sub.2. Further, 
in FIG. 23, since the analogue switch is used, the output V0 is also 
influenced upon the voltage reduction in this switch. 
Accordingly, in FIG. 23, if the voltage reductions in the diodes D1-D4 are 
the same, the values of the output V0 are different from each other, and 
accordingly, it is inconvenient that a certain value of the output V0 
corresponds to a given temperature unconditionally. 
In the illustrated embodiment, in consideration of the above fact, the 
following method is adopted for correcting the output V0 of the amplifier 
to detect the correct temperature. 
FIG. 24 shows an example of the procedure for obtaining the correction 
data, which correction can be carried out at the manufacturing stage or 
maintenance stage of the recording system. From the equation (2), 
EQU V0=C.sub.1 +A.multidot.V.sub.F (T) 
is obtained. Since the C.sub.1 is a constant having different values in the 
respective circuits, A is a fixed constant, and V.sub.F(T) is a function 
of the temperature, in order to seek the value C.sub.1 first, the voltage 
reduction corresponding to the value V.sub.F at for example 25.degree. C. 
is created at a portion corresponding to Dn (1.ltoreq.n.ltoreq.4), and the 
obtained values V0 are all A/D-converted by the CPU 454A (step S1, S3). 
Then, on the basis of the equation (2), for each circuit, the following 
equation is calculated to seek the value C.sub.1 (step S5): 
EQU C.sub.1 =V0-A.multidot.V.sub.F (T) (3) 
The obtained values C.sub.1 are stored in the nonvolatile memory 455 (for 
example, EEPROM and the like) (step S7). As a result, when the output V0 
is detected, from the equation (3), the following equation (4) is derived, 
and thus, the value A.multidot.V.sub.F (T) can be obtained: 
EQU A.multidot.V.sub.F (T)=V0-C.sub.1 (4) 
Thus, the temperature T can be easily sought from the previously determined 
relationship between the temperature T and the value A.multidot.V.sub.F 
(T) as shown in FIG. 25. 
In this way, when the temperature of each head is sought, by independently 
ON/OFF controlling the heat keeping heaters 410-413 arranged in the 
respective heads 409A, 409B, 409C, 409D corresponding to C ink, M ink, Y 
ink, BK ink (FIG. 22), it is possible to correctly control the head 
temperature at the desired temperature. 
FIG. 26 shows an example of the head temperature controlling procedure for 
the recording head of FIG. 23. 
When this procedure or sequence is initiated, first of all, the channel of 
the analogue switch 452 is designated by an output 0.sub.1 or 0.sub.2 
(step S11). Then, the output value V0 regarding the selected recording 
head is A/D-converted (step S13), and then, by using this value V0 and the 
constant C.sub.1 previously stored in the non-volatile memory 455, 
(V0-C.sub.1) is calculated (step S15). Next, on the basis of this result 
(V0-C.sub.1), the temperature T is calculated in accordance with the 
relation shown in FIG. 25 or is sought by referring to the table (step 
S17). By comparing the obtained temperature T with the control temperature 
T0 (step S19), the heat keeping heaters (i.e., temperature maintaining 
heaters) in each recording head are on/off controlled (step S21, S23). In 
this way, since the head temperature of each recording head is 
automatically adjusted during the operation thereof by the temperature 
adjusting apparatus according to this embodiment, the dispersion in the 
density, dispersion in the ink discharging speeds, dispersion in ink 
droplet reaching points and the like are considerably reduced, thus 
permitting the formation of good image. 
Embodiment 3 
In the above second embodiment, an example that the temperature features of 
the diodes used to the temperature sensors are uniform was explained. 
This example is useful in a case where the heater boards are obtained from 
the wafer of the same lot, since there is substantially no dispersion of 
the features of the diodes thereof. However, in effect, is since there is 
the dispersion between the lots, in this third embodiment, such dispersion 
is also corrected. 
When there is the dispersion in the values V.sub.F (T) for a predetermined 
temperature T, various values of V0 regarding the equation (2) (i.e., 
V0=C.sub.1 +A.multidot.V.sub.F (T)) at the predetermined temperature would 
be obtained. However, the temperature feature of the diode has a 
characteristic that the changing rate thereof is constant, although the 
voltage reduction V.sub.F thereof varies in a certain range in accordance 
with the temperature T, when the constant current flows in the diode, as 
shown in FIG. 27. Accordingly, when the standard feature of the diode is 
shown by a curve or line a, there arises the following relationship 
between the standard feature and a feature other than a: 
EQU V.sub.F '(T)-V.sub.F (T)=const. (5) 
Where, V.sub.F '(T) is, for example, a temperature feature of the diode 
having the feature as shown by the line b in FIG. 27. Thus, the difference 
between the line b and the line a is constant through all of the 
temperature range. 
Now, the constant C.sub.1 inherent to the circuit in the equation (2) is 
sought in the same manner as in the case of the above second embodiment, 
and is stored in the non-volatile memory 455. 
Further, a means for judging or discriminating the V.sub.F feature inherent 
to the diode is also provided in each recording head. Such means may 
include an additional non-volatile memory arranged in the recording head, 
which can store the necessary information and from which the information 
can read out as needed. 
Alternatively, as shown in FIG. 28, a pattern capable of having the judging 
information of a few bits (two bits in the illustrated example) is formed 
on the heater board, and, when the dispersion in the features of the diode 
sensors is checked, two-bit information may be obtained by cutting or 
short-circuiting the pattern of the recording head side. 
In consideration of the above, it is assumed that, when a certain recording 
head is connected to the circuit shown in FIG. 23, the recording head 
shows the following feature: 
EQU V0'=C.sub.1 +A.multidot.V.sub.F '(T) (6) 
(Incidentally, the value C.sub.1 has already been determined and stored in 
the non-volatile memory 455.) 
Now, in order to know the present temperature of this recording head, it is 
necessary to clarify the relationship between this temperature and the 
standard feature (line a in FIG. 27). If the diode has the standard 
feature, the equation (6) is expressed by: 
EQU V0=C.sub.1 +A.multidot.V.sub.F '(T) (7) 
From the equations (6) and (7), the following relation can be derived: 
EQU V0'-V0=A{V.sub.F '(T)-V.sub.F (T)} (8) 
Now, from the equation (5), it is found that the value in {} in the 
equation (8) is constant, and, since this value can be known by the means 
shown in FIG. 28, the right term of the equation (8) can be calculated by 
the CPU 454A. Thus, 
EQU V0=V0'-A{V.sub.F '(T)-V.sub.F (T)} (9) 
is calculated, and the value V0' can correspond to the value V0 in the case 
of the standard feature. When the value V0 is sought, similar to the 
second embodiment, the temperature T is sought by utilizing the relation 
shown in FIG. 25, and the proper head temperature control can be 
performed. 
FIG. 29 shows a control sequence in this third embodiment. In this example, 
between the step S13 and the step S15 in the sequence shown in FIG. 26, a 
process for classifying and judging the sensor information (step S14A) and 
a process for calculating the value V0 on the basis of such information 
and the circuit feature (step S14B) are inserted. 
Embodiment 4 
An example that the resistor sensors 442 shown in FIGS. 21A and 21B are 
used as the temperature sensors will be described. 
As shown in FIG. 30, the resistor sensor has a feature that the resistance 
value thereof increases as the temperature is increased. Also in this 
case, as in the case of the diode, there arises the dispersion in the 
features. The relationship between the temperature T and the resistance 
value R is given by the following equation: 
EQU R(T)=R0+.alpha..multidot.R0(T-T0)=R0{1+.alpha..multidot.(T-T0)}(10) 
Where, R is the resistance value .OMEGA.! at 25.degree. C., T0 is 
25.degree.C.!, and a is a temperature coefficiency inherent to the 
resistor 1/.degree.C!. When this resistor is used as the sensor, the 
detection output V0 thereof is expressed by the following relation, from 
the equation (2): 
EQU V0=C.sub.1 +A.multidot.i.sub.o R(T). (11) 
Also in this case, as in the case of the second embodiment, first of all, 
the constant C.sub.1 inherent to the circuit is calculated by using the 
reference resistance R0 as a reference value for this sensor and by A/D 
converting the value V0 at that time, and the calculated value C.sub.1 is 
stored in the non-volatile memory 455. 
Further, also in this fourth embodiment, in consideration of the difference 
r from the reference value R0 at 25.degree. C. in response to the 
dispersion in the features of the sensors, it is possible to obtain the 
information, for example, in the same manner as that shown in FIG. 28. In 
this case, the equation (10) can be rewritten as follows: 
EQU R'(T)=(R0+r).multidot.{1+.alpha..multidot.(T-T0)} (12) 
Accordingly, the detection output V0 obtained when the sensor having the 
feature R' is used becomes as follows: 
##EQU3## 
(where, C.sub.2 =C.sub.1 +Ai.sub.o (R0+r)(1-.alpha.T0)). 
From this, the temperature t is sought in accordance with the procedure 
shown in FIG. 29, and thus, the proper temperature control can be 
performed. 
Embodiment 5 
The environmental condition may be, for example, a humidity affecting an 
influence upon the viscosity of the ink. In this case, for example, in 
FIG. 23, in place of the temperature sensors, humidity sensors may be 
used, but the other elements are the same as those shown in FIG. 23. Also 
in this case, the temperature control can be performed in the same manner 
as described above. Further, various kinds of sensors may be used in 
combination. 
Incidentally, when the present invention is applied to the ink jet 
recording system, the present invention gives excellent advantages, 
particularly, in the bubble jet recording head and bubble jet recording 
system, for the reason that, since the thermal energy is used as an energy 
for effecting the recording in the bubble jet recording system, the 
control can be performed in response to the environmental condition 
(temperature) in consideration of the heat of the recording system. 
Preferably, the typical construction and principle thereof can be realized 
by using the fundamental principles, for example, disclosed in U.S. Pat. 
Nos. 4,723,129 and 5,740,796. Although this system can be applied to both 
a so-called "on-demand type" and "continuous type", it is more effective 
when the present invention is particularly applied to the on-demand type, 
because, by applying at least one drive signal corresponding to the record 
information and capable of providing the abrupt temperature increase 
exceeding the nucleate boiling to the electrical/thermal converting 
elements arranged in the sheets or liquid passages including the liquid 
(ink) therein, it is possible to form a bubble in the liquid (ink) in 
corresponding to the drive signal by generating the film boiling on the 
heat acting surface of the recording head due to the generation of the 
thermal energy in the electrical/thermal converting elements. Due to the 
growth and contraction of the bubble, the liquid (ink) is discharged from 
the discharge opening to form at least one ink droplet. 
When the drive signal has a pulse shape, since the growth and contraction 
of the bubble can be quickly effected, a more excellent ink operation can 
be achieved. Such pulse-shaped drive signal may be types disclosed in U.S. 
Pat. Nos. 4,463,359 and 4,345,262. Incidentally, by adopting the condition 
disclosed in U.S. Pat. No. 4,313,124 providing the invention regarding the 
temperature increasing rate on the heat acting surface, a further 
excellent recording can be performed. 
As the construction of the recording head, the present invention includes 
the construction wherein the heat acting portion is disposed in an arcuate 
area as disclosed in U.S. Pat. Nos. 4,558,333 and 4,459,600, as well as 
the constructions wherein the discharge openings, liquid paths and 
electrical/thermal converting elements are combined (straight liquid paths 
or orthogonal liquid paths). In addition, the present invention can 
applicable to the construction wherein each discharge opening is 
constituted by a slit with which a plurality of electrical/thermal 
converting elements associated in common as disclosed in the Japanese 
Patent Laid-Open No. 59-123670 and the construction wherein openings for 
absorbing the pressure wave of the thermal energy are arranged in 
correspondence to the discharge openings as disclosed in the Japanese 
Patent Laid-Open No. 59-138461, because the recording can be correctly and 
effectively performed regardless of the configuration of the recording 
head. 
Further, the present invention can be applied to a recording head of 
full-line type having a length corresponding to a maximum width of a 
recording medium to be recorded, as such recording head, the construction 
wherein such length is attained by combining a plurality of recording 
heads or a single recording head integrally formed may be adopted. In 
addition, among the above-mentioned serial types, the present invention is 
effectively applicable to a removable recording head of chip type wherein, 
when mounted on the recording system, electrical connection between it and 
the recording system and the supply of ink from the recording system can 
be permitted, or to a recording head of cartridge type wherein a cartridge 
is integrally formed with the head. 
Further, as to the kind and number of the recording head to be mounted, 
each recording head may correspond to each different color ink, or a 
plurality of recording heads can be used for a plurality of ink having 
different colors and/or different density. 
Furthermore, the recording system according to the present invention may be 
in the form of an image output terminal device for an information 
processing apparatus such as a computer, or a copying machine combined 
with a reader, or a facsimile having the sending and receiving functions. 
Lastly, the recording system to which the temperature adjusting apparatus 
of the present invention is applicable may not only the above-mentioned 
ink jet recording system, but also any ink jet recording systems other 
than the above type, or other recording system such as a thermal printer 
and the like. 
As mentioned above, according to the present invention, since the pattern 
acting as the information bearing means for carrying the information 
providing the features of the temperature detecting elements is previously 
arranged on the recording head, it is possible to correct the dispersion 
in the features of the temperature detecting elements obtained by the 
semiconductor process with a very simple method and arrangement, and to 
perform the proper temperature control. 
Further, according to the present invention, by previously setting the 
reference value as the detection output of the element and, by storing 
such detection output or the result obtained by effecting the 
predetermined calculation by using such detection output in the memory 
means, since the error of the detecting elements being used can be 
corrected on the basis of the contents stored in the memory means when the 
temperature adjustment is effected in accordance with environmental 
condition, it is possible to obtain the high accurate measurement result 
without adjusting the output voltage level regarding the rated error of 
the detecting element and/or the offset voltage of the amplifying circuit, 
and to reduce the number of adjustments in the mass-production line. 
Further, even when the detecting elements is one of consumption parts, it 
is not necessary to perform the level adjustment during the exchange of 
the consumption parts. 
In addition, since the head temperature adjustment during the operation is 
automatically effected for each recording head by means of the temperature 
adjusting apparatus according to the present invention, the dispersion in 
the density, the dispersion in the ink discharging speeds and the 
dispersion in the ink reaching points can be considerably reduced, thus 
permitting the formation of the high quality image.