Recording apparatus, recording head and substrate therefor

A substrate having plural recording elements and electrical leads for supplying electric signals to the recording elements includes electrical contacts for external electrical connection for reception of image signals used for driving the recording elements; and a processing circuit for converting signals which are serially supplied to the connecting contact to parallel signals to be applied to the recording elements.

FIELD OF THE INVENTION AND RELATED ART
 The present invention relates to a recording apparatus, a recording head
 usable therewith, and a substrate for a recording head. The recording
 apparatus is used as an output machine for a copying machine, a facsimile
 machine, a word processor, a host computer or the like. More particularly,
 it relates to the same in which a plurality of recording elements are
 used, which are selectively driven by integrated circuit for the driving.
 Various types of recording machines are known. Among them, a liquid
 ejection recording apparatus in which ink is ejected through ejection
 outlets provided for the respective recording elements, are desired
 because of the advantages of the low noise non-impact recording operation,
 capability of high density recording, capability of high speed recording.
 The recent demands for such apparatus includes the compactness and low
 cost.
 Among the liquid jet recording apparatus, a type using electromechanical
 converters (piezoelectric elements, for example), a type using
 electrothermal transducers and a type using pairs of electrodes supplied
 with a voltage to elect liquid droplets, are known. Further among them, an
 ink jet recording apparatus of a type in which the recording liquid is
 ejected using thermal energy, has been commercialized because of its
 advantages that the liquid ejection outlets (orifices) can be arranged at
 high density with the result of capability of high resolution recording
 and that the multi-nozzle (orifice) arrangement is relatively easy with
 the result of capability of the high speed printing.
 In a known recording head used with the recording apparatus of this type, a
 plurality of recording elements are arranged in a line, and the recording
 elements are divided into plural blocks each having several tens recording
 elements, and several or several tens driving circuits for the respective
 blocks, are formed on one substrate as integrated circuits. The recording
 elements are selectively driven in accordance with image data by the
 driving circuits, so that the recording is effected on the recording
 material such as paper.
 These recording heads are particularly noted because of its high resolution
 and high speed recording. However, further reduction of the cost and the
 size and the improvement of the performance, color printing function, or
 the like are desired. Referring to FIG. 29, there is shown a conventional
 substrate (heater board) having recording elements thereon and a schematic
 sectional view of the ink jet recording head using the substrate.
 In FIG. 29, (d), reference numeral 1 designates a heater board having
 thermal energy generating means in the form of an electrothermal
 transducers 2 a top plate 17 is provided with grooves constituting a part
 of passages for ink 3. The ink 3 is supplied through the passages formed
 by the heater board 1 and the top plate 17, as indicated by an arrow A.
 The ink is then heated by the electrothermal transducers 2 on the heater
 board 1 so that the ink is ejected through the ejection outlets 5 in the
 direction indicated by an arrow B. In FIG. 29, (a)-(c), show arrangements
 of various elements in the heater board 1. It includes electrical leads
 for electrically connecting various elements, diode arrays 7, and pads 8
 for external electrical connection. In the arrangement of FIG. 29, (a),
 the electrothermal transducers 2, the electrical leads 6, the diode arrays
 7 and the pads 8, are disposed in the order named from the ejection outlet
 5 side.
 In FIG. 29, (b), the electrical connection between various elements are the
 same as in FIG. 29, (a), but the electrical leads 6 portion and the diode
 array 7 portions are mixed. In FIG. 29, (c), the electrothermal
 transducers and the pads 8 are arranged with one-to-one relation
 therebetween.
 In an arrangement of FIG. 30, (a), (b) and (c), an ink supply port 9 is
 formed in the heater board 1 having the electrothermal transducer, as
 contrasted to the case of FIG. 29. In this case, the ink is supplied from
 the backside of the substrate cover as indicated by an arrow A, and the
 ink is ejected in a direction substantially perpendicular to the surface
 of the substrate 1, as indicated by an arrow B.
 As for the wiring in the heater board shown in FIG. 29 or 30, two types are
 known. In one of them, as shown in FIG. 29, (c), and FIG. 30, (a)-(c), and
 FIG. 31 designating the equivalent circuit, the electric signals are
 supplied from the pads 8 to the electrothermal transducers in one-to-one
 relation (direct drive type). In the other type, as shown in FIG. 29, (a)
 and (b) and FIG. 32 showing an equivalent circuit, a matrix arrangement
 using diodes are used, in which the electrothermal transducers are
 selectively driven by selective drive voltage application between segment
 pads SEG and common pads (matrix drive type).
 In the direct type shown in FIG. 31, n pads 8 are required for n ejection
 heaters (electrothermal transducers) 2. In addition, VH pad is required,
 and therefore, (n+1) pads are required in total. Since the pads 8 are
 directly connected to the ejection heaters 2, a large current such as
 approx. 150 mA. With a pulse width of 7 .mu.S in a 360 dpi recording head
 for plain paper according to an example of experiments by the inventors,
 flows therethrough. In addition, the same current multiplied by n, flows
 through the VH pad. Thus, all the electrical leads have to be designed for
 large current. Because of the number and large size of the pads, a large
 area is required for the wiring with the result of bulky substrate and
 recording head and high manufacturing cost. From the standpoint of the
 main assembly of the recording apparatus, the connecting portion and the
 wiring therein are complicated due to the large number of the pads.
 FIG. 32 shows another type of matrix drive system. The number of electrical
 leads and the pads is decreased as compared with the above-described
 direct type. However, when n ejection heaters 2 are used, the minimum
 number of pads is 2n (when 2n is not an integer, the value is rounded, and
 added by 1) are required at minimum. The electric current flowing through
 the common electrode (COM) pad is the electric current per one ejection
 heater multiplied by the number of ejection heaters connected with the
 matrix, as the case may be, and therefore, the electrical leads 12 have to
 be designed for the large current.
 Generally, in an ink jet recording head, there is a liability that the
 pressure wave at the time of bubble formation is transmitted toward
 upstream (toward a common liquid chamber) in the form of a back wave, with
 the result of fluid cross-talk among nozzles. Therefore, simultaneous
 drives of adjacent nozzles may result in instable ejection due to the back
 wave. In view of this, it is desirable that the simultaneous drives are
 effected for nozzles which are spaced greatly, from the standpoint of
 stabilized ejection and high image quality. However, in the case of the
 above-described matrix drive circuit, if the common electrode
 simultaneously drives a large number of different driving elements (COM),
 large current flows through the thin segment (SEG) leads with the result
 of potential difference within the leads. If this occurs, the
 electrothermal transducers are not supplied with proper electric energy.
 For this reason, there is a problem that the large number of elements are
 not driven.
 The problem of the large number of pads and the complicated wiring in the
 heater board, is more significant in the case of color recording.
 In order to accomplish the color recording, the recording apparatus is
 provided with a plurality of recording head for the respective colors.
 FIG. 33 is a block diagram of a circuit structure for a conventional liquid
 jet recording apparatus for color recording. Designated by references 2C,
 2Y and 2M are recording elements (electrothermal transducers) for cyan,
 yellow and magenta recording. Several tens of such elements are used.
 Function elements 10 are for controlling power supply to the recording
 elements. A shift register circuit 11 aligns the image data, corresponding
 to the recording elements. It is directly connected with a latching
 circuit 12 storing data for the recording elements. By using an output of
 an AND gate receiving as inputs an output of the latching circuit and an
 output of another AND gate connected at the input to the signal lines 14
 and 15 for controlling the power supply period to the recording elements,
 the recording element can be supplied with the power during the output
 period of the first mentioned AND gate. In the Figure, the zone indicated
 by the broken line is formed on the substrate, and therefore, the
 electrothermal transducers 2, function element array (transistor array 10
 in this embodiment) for selectively driving the electrothermal transducers
 2, are formed on the substrate.
 With this structure, however, the number of contacts between the recording
 head carriage (main assembly) and the electrical leads is still large with
 the result of complicated driving circuit. Therefore, the design and
 productions are still difficult.
 U.S. Pat. No. 5,030,971 discloses that in order to reduce the size of the
 color recording apparatus, the substrates for the different color are made
 integral. In the U.S. patent, the elements for the four colors are formed
 on the same substrate. The driving circuit in this patent is in the diode
 matrix type, and therefore, the number of electrical leads is small as
 compared with the case of the direct driving system, and therefore, the
 size of the recording head itself can be reduced. This will be
 satisfactory if the number of electrothermal transducers is small.
 However, if the number is increased to meet the demand for the high speed
 recording, for example, the number of electrical leads and the pads
 increases accordingly, with the result that the above-described problem
 arises.
 As regards the manufacturing of the substrate, the yield decreases with
 increase of the number of recording elements (electrothermal transducers),
 since the number of diodes and transistors also increases. Also, the yield
 in the formation of the ink ejection outlets or the like by connection
 with the substrate, and therefor, it has been difficult to manufacture the
 substrate having a large number of recording elements.
 In the case of the substrate having the supply port as shown in FIG. 30,
 the utilization factor of the silicone wafer constituting the substrate
 can not be increased with the result of high cost.
 SUMMARY OF THE INVENTION
 Accordingly, it is a principal object of the present invention to provide a
 substrate, a recording head using the same and a recording apparatus using
 the same, in which the wiring on the substrate is simplified.
 It is another object of the present invention to provide a substrate, a
 recording head using the same and a recording apparatus using the same in
 which a number of pads on the substrate is reduced, so that a larger
 number of recording elements can be formed on the substrate.
 It is a further object of the present invention to provide a substrate, a
 recording head using the same and a recording apparatus using the same,
 wherein even when a large current is used, the current is not concentrated
 locally on thin electrical leads.
 It is a yet further object of the present invention to provide a substrate,
 a recording head using the same and the recording apparatus using the same
 in which a number of electrical connection pads is increased, so that the
 wiring can be simplified and that the manufacturing is easy, the size is
 reduced and the cost is reduced.
 According to an embodiment of the present invention, there is provided a
 substrate having plural recording elements and electrical leads for
 supplying electric signals to the recording elements, comprising:
 electrical contacts for external electrical connection for reception of
 image signals used for driving the recording elements; and a processing
 circuit for converting signals which are serially supplied to the
 connecting contact to parallel signals to be applied to the recording
 elements.
 According to another embodiment of the present invention, there is provided
 an ink jet recording head having a substrate with plural recording
 elements and passages for supplying liquid to a neighborhood of the
 recording elements, the improvement residing in the substrate, comprising:
 electrical contacts for external electrical connection for reception of
 image signals used for driving the recording elements; and a processing
 circuit for converting signals which are serially supplied to the
 connecting contact to parallel signals to be applied to the recording
 elements.
 According to a further embodiment of the present invention, there is
 provided a recording apparatus for effecting recording operation with ink
 droplets ejected, comprising: a recording head having a structure defined
 above; and electrical signal contact connected with the recording head to
 supply the signal thereto.
 These and other objects, features and advantages of the present invention
 will become more apparent upon a consideration of the following
 description of the preferred embodiments of the present invention taken in
 conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring to FIG. 1, there is shown a semiconductor chip 1, according to an
 embodiment of the present invention. Recording elements are arranged in
 the longitudinal direction of a substrate 1 in a recording element zone 2.
 Each of the recording elements are connected to a common electrode 21 at
 the power supply side, by through hole. Designated by reference numeral
 821 is a power supply pad (VH) for the recording elements. Function
 element arrays 22 and 23 control the power supply to the recording
 elements, and are arranged so as to permit high density printing.
 Designated by reference numeral 24 is common grounded electrode (GND) for
 the recording current for the recording elements. The area thereof is
 determined depending on the current level supplied to the recording
 elements. Designated by a reference numeral 824 is a grounding pad. One of
 the features of the present invention is in a logic circuit zone 25 in
 which there are provided a logic gate zone 26, a latching circuit 12,
 shift registers 11 and 27 are formed on the surface of the semiconductor
 chip in the form of a driving integrated circuit. The logic circuit 25
 functions to control the function element arrays connected to the
 recording elements (thermal transducer elements).
 FIG. 2 shows an example of an equivalent circuit of the substrate having
 the structure as shown in FIG. 1. The recording element 2 is connected
 with a transistor 23 for selecting the recording element 2. There is shown
 an enabling leads (15) for actuating the recording element at a given
 timing, a latch 12 for latching the printing data corresponding to the
 recording elements, input leads (17) for receiving serial data and a shift
 register 11 for shifting the serial data with predetermined timing.
 FIG. 3 is a further equivalent circuit of the equivalent circuit of FIG. 2.
 The fundamental circuit structure is the same as that shown in FIG. 2, but
 in this circuit, the two enabling signal leads are replaced by one lead.
 FIG. 4 is an operating timing chart of the circuit of FIG. 3. In FIGS. 3
 and 4, recording elements are indicated as n heaters R1-Rn, as an example.
 The circuit comprises a transistors 22, logic gates 13, a latching circuit
 12 and a shift register 11. It further comprises pads 821-829 including
 the VH pad 821, GND pad 824, a strobe pad 825, a latch pad 826, a data pad
 827, a clock pad 828 and logic power source VDD pad 829.
 Referring to FIG. 4, the operation of the circuit of FIG. 3 will be
 described.
 Clock signals 18 and serial data signals 18 synchronized therewith are
 supplied to the shift register circuit 11 at the timing shown in FIG. 4.
 When all of n data are set, a latch signal (negative logic) 16 shown in
 FIG. 4 is supplied to the latch circuit 12, by which the supplied data are
 stored. The data are kept stored until the next latching signal is
 supplied. Then, an AND-output of the strobe signal 14 and the latch
 output-provided by the logic gate 13 is supplied to the transistors 22 and
 23, so that the driving signals for the heaters R1-Rn (output signals of
 the transistors) are produced. In this embodiment, the driving signal wave
 form is determined by the input wave form of the strobe signal 13
 (enabling signal (El), in the case of FIG. 2 example).
 In the circuit of FIG. 3, the output timing of the driving signals for the
 heaters R1-Rn, are simultaneous in synchronism with the strobe signals 14.
 In the case of the timing chart of FIG. 4, the different timing is usable,
 when a delay circuit is used as shown in FIG. 18 which will be described
 hereinafter.
 As will be understood from FIGS. 1-4, the minimum required number of pads
 for the heater board is seven, irrespective of the number of recording
 elements 2, in this embodiment. Therefore, the complication of the
 electric wiring attributable to the high density nozzle arrangement, can
 be avoided.
 The following Table 1 gives the minimum required pad numbers on the heater
 board in relation to the number of ejection heaters, in various driving
 systems.
 TABLE 1
 No. of
 Heaters Min. Required No.
 (m) Direct Drive Matrix Drive This Embodiment 1
 8 9 6 7
 16 17 8 7
 64 65 16 7
 4736 4737 138 7
 As will be understood from Table 1, when the number of ejection heaters 2
 is larger than 16, the number of pads is smaller in this embodiment than
 in the direct driving system or in the matrix driving system. The
 advantageous effect is even more remarkable when the number of the heaters
 increases. When a line head (covering A4 size with 400 dpi) is considered,
 the number of nozzles is as large as 4736, and therefore, the number
 difference between the prior art system and the present embodiment system
 is greatly significant.
 Furthermore, in this embodiment, four pads, namelly the strobe pad 825, the
 latch pad 826, the data pad 827 and the clock pad 828 among the seven
 pads, deal with logic signals, and not in the power supply line, and
 therefore, the large current does not flow therethrough. For this reason,
 the size of the electrical leads may be small. The electrical leads
 therefor can be arranged in smaller space. This permits a larger size
 electrical leads for the power supply for the heater. Accordingly, even
 upon the electric current concentration occurred, the electric power loss
 hardly occurs.
 Referring to FIG. 5, there is shown a structure of the substrate of FIG. 1
 according to an embodiment of the present invention. The basic material of
 the substrate is usually silicon, but it may be another material if a
 semiconductor can be formed thereon. The substrate 1 comprises a basic
 semiconductor layer 1029, and the semiconductive element has been formed
 through known ion implantation or the like. The semiconductive elements
 are designated by reference numerals 10, 1016, 1023, 1024, 1025 and 1026.
 On the semiconductor layer 1029, a first electric insulating layer 1028 is
 formed, and an electric conductive layer Is patterned on the insulative
 layer. The conductive layer is properly contacted to the semiconductive
 layer 1029 for establishment of the circuit structure of FIGS. 2 and 3 via
 through holes (not shown).
 The first conductor on the insulating layer 1028 includes VH leads 21 for
 supplying the electric energy required for bubble creation of the liquid,
 GND leads 24 for the electric grounding of the leads 21, enabling leads
 1019 for actuating the electrothermal transducers 2 at given timing, latch
 leads 1020 for latching the print data, serial data leads 1021 for
 supplying the serial data and clock leads 1022 for shifting the serial
 data at predetermined timing. On the first conductor, there is provided a
 second insulating layer 1027, and a second conductive layer is provided
 thereon which is properly contacted via through holes. To the ejection
 heater 2, the electric energy is supplied through VH-heater lead 32 via a
 through hole contact. The other end of the heater is connected to a
 collector of a transistor 10 via through hole of the first insulating
 layer and through a heater-transistor lead 33. The first transistors 10
 and the second transistors 10 are arranged in two lines, but they are
 staggered to improve the area factor.
 When, for example, the heater arrangement pitch is small, the transistor
 are arranged in plural lines since the area factor is better if the
 configuration of the transistor is close to right square. The other end of
 the transistor 10 (base) is connected to the logic gate 1023 via
 transistor base line 28. The transistor base lead 28 is made of
 polysilicon or the like. As for the first and second conductive layer
 material, aluminum or other low resistance material is used. The other end
 (emitter) of the transistor 10 is connected to the GND lead 24 via through
 hole and through the transistor-GND line. The logic gate 1023 selectively
 transmits ON-signal to the transistor through the enabling line 1019.
 Because of the driving nature of the enabling line 1019, the electrothermal
 transducer elements 2 are independently actuatable. The current flowing
 through the enabling line 1019 is very small, and therefore, the power
 loss is small even if the wiring thereof is complicated, and therefore,
 the ejection heaters 2, can be selectively actuated.
 Referring to FIG. 6, an example of manufacturing process of the substrate 1
 shown in FIG. 5, will be described. This Figure illustrates the process
 steps after the latching circuit 12, the shift register circuit 11 and the
 transistors 10 and the like have been manufactured through ion
 implantation or diffusion. In FIG. 6, designated by (a) is a top plan
 view, and (b) is a partial sectional view.
 In this embodiment, the signal line for actuating or deactuating the
 transistor by application of logic signals from the shift register 11 to
 the transistor 10, are provided by the semiconductive layer. This is
 permitted because the electric current between the shift register 11 and
 the transistor 10 is very small, and therefore, there is no need of
 providing electric lines for this purpose.
 Further, in the structure of the substrate of this embodiment, the
 transistors 10 are staggeredly arranged as shown in FIG. 6(a) with
 alternatingly different distances from the shift register, thus increasing
 the pattern integration. In the case of the substrate for the ink jet
 recording head or apparatus, the electric current flowing to the recording
 element through the transistor is large, which requires large area
 transistors. However, from the standpoint of high resolution recording,
 the distance between adjacent recording element is desired to be small.
 The staggered arrangement permits both requirements. In this embodiment,
 the distances from the shift register to the transistor is changed in two
 steps, but a larger number of steps is usable.
 FIGS. 7, 8 and 9 show the manufacturing steps, and the manufacturing steps
 proceeds in the order of (a), (b) of FIG. 7, FIG. 8, FIG. 9, (c) and (d)
 of FIG. 7.
 In FIG. 7, (a), SiO.sub.2, SiN or the like between-layers insulating film
 29 is formed on the substrate shown in FIG. 6, and through holes have been
 formed for the electric connection with the upper layer.
 In FIG. 7, (b), the first lines are formed with aluminum or the like for
 the VH common electrode 21, the grounding line 24, the logic line 31, for
 the contact 30 or the like.
 As shown in FIG. 8 by (a), (b), a second SiO.sub.2 or SiN (Si.sub.3
 N.sub.4) or the like between-layers insulating film is formed on the first
 wiring layer, and through holes are formed therein. On the second
 insulating film, a second aluminum layer is formed, and is patterned, so
 that the electric connections between the electrothermal transducers 2 and
 the VH electrode and the transistors, and the pads, are formed (FIG. 9).
 Subsequently, in order to avoid the short circuit between electrodes
 through the ink, a protection layer 36 is formed, as shown in FIG. 7, (c).
 On the protection layer, an anti-cavitation layer 37 made of Ta or the
 like may be formed, as shown in FIG. 7, (d). The anti-cavitation layer 37
 functions to protect the electrodes and the other layers from cavitation
 liable to occur bubble creation and collapse in the ink.
 Referring to FIG. 10, the description will be made as to the structure of
 the ink jet head using the heater board 1 described above. A top plate 4
 includes n orifices 5 and grooves in communication therewith,
 respectively, although not shown in the Figure. When the top plate 4 is
 combined with the heater board 1, n recording elements 2 correspond to the
 respective grooves, and therefore, the respective orifices, and in
 addition, the ink chamber is formed. The electrical pads 8 are disposed in
 marginal portions of two sides of the heater board 1. They are connected
 to the external lines for reception of the electric energy, and are
 connected therewith through wire bonding, gang bonding, bumping, clamping
 or the like.
 The member constituted by the top plate 4 and the heater board 1 is mounted
 on an ink container cover 38. The ink container cover is combined with an
 ink container case to constitute an ink container for accommodating the
 ink therein. In the ink container, an ink absorbing material may be
 contained to retain the ink therein, although not shown. The ink is
 supplied to the nozzle through an ink supply passage of the ink container
 cover 39 through a bottom portion of the recording element array 2 of the
 heater board 1. This is best seen in FIG. 11 which is a sectional view.
 The ink is supplied to the backside of the heater board 1 adjacent the
 position where the recording elements 2 are arranged, through the supply
 passage formed in the ink container cover 39. Then, the ink reaches to the
 surfaces of the individual recording elements through the nozzles of the
 top plate 4. Here, the ink is heated by the ejection heater 2 so that a
 bubble is created. By the pressure of the bubble creation, the ink is
 ejected out through the orifices 5 onto the recording material to form
 dots. As shown in FIG. 12, the ink is supplied to the surface of the
 ejection heater 2, the droplet of the ink 42 is ejected by the pressure
 resulting from the bubble creation 41.
 The ink supply around the backside of the substrate at the position having
 the recording elements, the non-uniform temperature distribution of the
 substrate is decreased, thus stabilizing the recording action. In
 addition, the distance between the recording element position and the ink
 supply chamber 43 can be decreased to the minimum, and therefore, the ink
 refilling speed can be increased, thus accomplishing the high speed
 response of the ink ejection.
 The back wave described hereinbefore can be diffused firstly because the
 distance is short between the bubble creating position (recording element
 position) and the common chamber 43 position and secondly because the
 diffusing rate of the configuration of the passage to the liquid chamber
 43 can be increased. Thus, the cross-talk attributable to the production
 of the back wave between nozzles, can be minimized. In order to assure
 these advantageous effects, the recording elements are preferably disposed
 within 1000 microns from an edge of the substrate, and further preferably,
 it is within 300 microns. Here, the position of the recording element is
 determined on the basis of the distance from an end of the common liquid
 chamber to the center of the recording element in the direction along the
 liquid passage.
 In the foregoing embodiments shown in FIGS. 10-12, the ink jet recording
 head using the substrate is of the type wherein the ink is ejected in the
 direction substantially perpendicular to the surface of the recording
 element.
 Referring to FIGS. 13 and 14, there is shown an example of the recording
 head in which the ink is ejected in the direction parallel to the surface
 of the recording element. FIG. 13 is a partial sectional view thereof, and
 FIG. 14 is a sectional view.
 In the Figure, a top plate 4 having grooves for constituting liquid
 passages 47 is joined with the substrate 1. The ink is supplied to the
 liquid passages 47 from the common liquid chamber 43, and the ink is
 supplied to the orifice by capillary force. The electric signals are
 applied to the recording elements corresponding to the liquid passages 47,
 and heat is generated by the corresponding recording elements. Then, the
 ink is heated, and a bubble 41 is created. By the pressure caused by the
 bubble creation, the ink is ejected through the ejection outlet 5. To the
 substrate according to this embodiment, having the shift register,
 recording electric signals are supplied through the wire bonding pads 45
 from a print board 46.
 FIG. 15 is a circuit diagram of the recording head element substrate
 capable of color recording, according to an embodiment of the present
 invention. The recording elements 2C, 2Y and 2M are for cyan, yellow and
 magenta recording actions. Several tens of the recording elements are
 used. Function element 10 are the same as described in the foregoing. A
 shift register circuit 11 functions to align the image data in relation to
 the recording elements. It is directly connected with a latching circuit
 12 for holding the data for the recording elements the strobe signal 14 is
 capable of controlling the on-period for the recording element. The
 signals 1034C, 1034Y and 1034M is capable of activating independently the
 respective color function element blocks. An output is provided from an
 AND gate receiving the strobe signal 14 and the signal 1034C, 1034Y,
 1034M. The output of the AND gate is supplied to an additional AND gate,
 which also receives an output of the latching circuit. The output of the
 additional AND gate permits electric power supply to the recording element
 for the period during the outputting time. According to this embodiment, a
 small and low cost recording apparatus can be achieved by forming plural
 color recording elements on the semiconductor chip (substrate).
 FIG. 16 is a drive timing chart of a recording apparatus according to the
 embodiment of the present invention. One of the features of this
 embodiment is that the image data for plural colors are serially supplied
 at the time of the image data signal (SI) supply. In other words, the
 image data for plural colors are not separately supplied, but is
 sequentially and serially supplied to a single image data signal input
 terminal 17 for the cyan, yellow, magenta (black may be added) colors. The
 serial image data for plural colors are sequentially transferred in the
 shift register 11 with the aid of transfer clock (SCK), so that the image
 data for the plural colors are aligned for one line of the recording
 elements for the respective recording heads. The shift register 11 shown
 in FIG. 15 is electrically connected with the latching circuit 12 to
 permit electric power supply to the recording elements in relation to the
 image data for the one period of the latch pulse signal (LAT) 16.
 Actually, the recording elements are driven dividedly for the respective
 colors, in the periodical time duration capable of driving the recording
 elements. The dividing operation is carried out in response to enabling
 signals 1034C, 1034Y and 1034M. By the use of this signal and the strobe
 signal 14 for determining the driving period which is proper for the
 respective colors (the actuating pulse widths matching the respective
 recording elements), the recording element blocks divided for the plural
 colors, can De selectively driven with constant pulse widths during the
 periodical time duration determined by the latching pulses.
 Because of the use of the drive timing described above, even if the
 recording operation is carried out in plural colors, there is no need of
 providing respective signal lines for the colors, so that the number of
 electrical leads and the number of pads can be reduced. Therefore, the
 size and cost of the recording head Substrate and the recording head, can
 be provided. In the foregoing description, the case of three color
 recording is taken. However, the similar driving method ran be used for a
 larger number of colors, or for mono-color recording.
 In the case of the monochromatic recording, the same structure as in the
 color recording is usable. By doing so, both of the color recording
 operation and the monochromatic recording operation are enabled only if
 the recording head is exchanged. As regards the discrimination between the
 color recording and the monochromatic recording, a discriminating code may
 be provided in the serial data, and the data is fed back from the
 recording apparatus to the printer. It is a possible alternative that the
 recording head may be provided with a cut-away portion which is detected
 by the printer.
 FIG. 17 shows an embodiment in the form of a color recording head
 cartridge, in which the advantageous effects of the present invention are
 best used. A top plate 4 is provided with ejection outlets 5M, 5Y and 5C
 for magenta, yellow and cyan colors, respectively and with grooves for
 constituting passages connected therewith. A semiconductor chip
 (substrate) 1 has plural recording elements, function elements and driving
 integrated circuits integrally on the surface thereof. The surface thereof
 is provided with electric pads 8 for connection with the respective color
 recording elements 2M, 2Y and 2C and for connection with power source. The
 common chamber 39 for supplying the ink materials to the respective
 ejection outlets, are divided in this example into the common chambers
 39M, 39Y and 39C, for the respective colors. The ink supplying common
 chambers 39M, 39Y and 39C are ink supply containers 40M, 40Y and 40C,
 respectively. In this embodiment, the size and cost are reduced. The
 fundamental mechanism and the operation of the recording head of this
 embodiment is the same as those of FIG. 10 embodiment, and therefore, the
 detailed description thereof is omitted for simplicity.
 Here, an example of the recording head in which the ink is ejected in the
 direction substantially perpendicular to the surface of the recording
 element, is taken. However, this embodiment is applicable to the recording
 head of the type shown in FIGS. 13 and 14, in which the ink supply system
 is divided for the respective ink colors.
 In the embodiment, the elements for the respective colors are formed on a
 single substrate for the color recording head. However, plural substrates
 may be cascade-connected to meet the color demand the long recording head
 demand.
 FIG. 18 shows an equivalent circuit in the wiring of the substrate which is
 cascade-connected with another substrate. FIG. 19 shows a substrate having
 such a circuit.
 As contrasted to the case of FIG. 3, output contacts 831-833 are provided
 for the cascade connection for the latching circuit 12 and the shift
 register 11, as contrasted to FIG. 3 embodiment. The substrate is
 connected with another substrate through the output contacts. By doing so,
 plural substrates may be driven by a data input signal required for
 driving one element substrate. In this case, to the driving operation is
 substantially the same as in the foregoing embodiment.
 Conventionally, in the case of the substrate or recording head having a
 large number of recording elements, the manufacturing cost is quite
 increased for the purpose of increasing the yield. However, according to
 this embodiment, the number of connecting lines can be reduced even when
 plural substrates are connected to increase the number of recording
 elements into an elongated recording head as in a full-line recording
 head, and the manufacturing cost and the design and manufacturing
 easiness, can be maintained.
 In FIG. 19 embodiment, the number of output contacts is larger than that in
 the equivalent circuit of FIG. 18. However, this results from having made
 the strobe signal lines or the like common with the other substrate. As to
 how many lines are made common, it is determined in consideration of the
 entire design of the recording head by one skilled in the art.
 FIG. 20 shows an embodiment in which the semiconductor chips or substrates
 as described hereinbefore are cascade-connected in relation to the colors,
 and still the high speed printing is possible. THe connecting pads 8 of
 the semiconductor chips 1M, 1Y and 1C for the respective colors, are
 cascade-connected with connecting elements (or wire bonding or the like)
 49. FIG. 21 shows a circuit diagram of this structure. Basically the
 contacts for the power supply are made common, and the signal line
 contacts are cascade-connected. The equivalent circuit for the respective
 colors in this embodiment is substantially the same as in FIG. 15
 embodiment, and therefore, the detailed description thereof are omitted
 for simplicity. When the cascade-connection is made, the image data
 corresponding to the total number of recording elements, are serially
 supplied for the respective colors in the case of the color recording, and
 in the case of the monochromatic recording, the monochromatic data
 corresponding to the total number of recording elements are serially
 supplied. FIG. 22 is a drive timing chart for driving the recording
 apparatus of this embodiment.
 When the semiconductor chip recording elements are arranged in the
 staggered manner, a higher speed and a higher density printing becomes
 possible, as shown in FIG. 24. The relaying member or substrate is mounted
 on the substrate for supporting the semiconductor chip. This structure is
 advantageous in that when the recording element or the semiconductor chip
 is damaged for one reason or another, the semiconductor chip may be
 exchanged as a unit.
 With this structure, the maintenance free use is possible. Since the
 recording elements corresponding to a recording width for one line and the
 function elements therefor and also the driving integration circuit, are
 structurally formed on the same substrate, so that the full-line recording
 apparatus capable of high reliability, high density and high speed, can be
 provided.
 FIG. 25 shows a recording head unit provided by the connection of the
 substrates shown in FIG. 24.
 FIG. 23 shows non-full-line type recording head, in which the recording
 elements corresponding to several tens semiconductor chips, the function
 elements and the drive integration circuits are formed on the same
 substrate, and the recording elements are grouped for the respective
 colors, and the respective liquid chambers 43M, 43Y and 43C are formed. By
 doing so, a color liquid ejection recording apparatus of high reliability,
 high density and high speed printing, can be provided. Designated by
 references 51M, 51Y and 51C are ink supply pipes for the magenta, yellow
 and cyan ink materials. As described hereinbefore, the liquid chamber may
 be separated for the respective colors in the case where the plural
 substrates are cascade-connected in a color recording head. Although not
 shown the liquid chamber is not divided and a monochromatic full-line
 liquid jet recording apparatus may be provided.
 Referring back to FIG. 18 showing an equivalent circuit capable of the
 cascade connection, it is different from the circuit of FIG. 3 in that the
 FIG. 18 circuit includes a delay circuit 48. The delay circuit of FIG. 18
 will be described, referring also to the timing chart of FIG. 4.
 Similarly to the foregoing embodiments, the clock signals 18 and the serial
 data signals 17 synchronized therewith, are supplied to the shift register
 circuit 11. When the plural heater boards 1 are cascade-connected. The
 number of clock signals 18 and the data 17 is the number of cascade
 connection m multiplied by the number n of the heater on the heater board.
 When all the data are set, the latching signal 16 is supplied to the
 latching circuit 12, so that the data is held.
 With this state, a strobe signal 14 is supplied to the delay circuit 48. In
 the delay circuit 48, the delay time can be set for the respective heaters
 in relation to the input wave form of the strobe signal 14. It produces
 logical product of the delay wave form and the latching data signal. The
 ejection heater receives the logical product signal of the delay output
 and the enabling signal 15. Where the plural substrates 1 are
 cascade-connected, the enabling signal is effective to select the
 substrate 1 to be actuated by the signal, when only a selected substrate
 is to be actuated.
 In this embodiment, any delay can be selected for the respective heaters by
 the addition of the delay circuit 48. This produces the following
 advantageous effects:
 (1) Since the instantaneous current flow decreases due to the decrease of
 the number of simultaneously driven heaters, and therefore the voltage
 drops through the VH and GND lines can be minimized: and
 (2) It is possible to provide such a delay as to prevent the simultaneous
 actuation of adjacent heaters, in consideration of the problem that when
 the adjacent heaters are simultaneously driven in the ink jet recording
 head, the fluid cross-talk problem or the temperature rise might arise.
 In this embodiment, the substrate 1 has a built in delay circuit for
 determining the drive timing, but the same advantageous effects can be
 provided by using plural strobe signal contacts.
 Referring to FIG. 26, another embodiment of. the circuit arrangement on the
 element substrate will be described. In FIG. 26, (a), the VH lines 54 and
 the GND lines are disposed immediately behind the electrothermal
 transducer element array 2, and they are connected with minimum distance
 therebetween, and therefore, the electric loss is minimum.
 In the structure shown in FIG. 26 by (b), a top plate having passage
 constituting grooves is bonded to the substrate, as described
 hereinbefore, since the element substrate of this invention is mainly used
 for ink jet recording head. In order to enhance the contactness between
 the top plate and the substrate, it is preferable that the flatness of the
 surface of the substrate is high. In FIG. 26, (b), the intersection
 between first and second lines, occur at a position away from the
 recording elements where the high flatness is particularly desired. In the
 arrangement shown in FIG. 26 by (c), the VH line 21 is disposed closer to
 the substrate edge than the recording element array, and therefore, the
 circuit wiring is possible without necessity for the multi-layer structure
 of the wiring. Therefore, the cost is reduced. In addition, there is no
 fold-back wiring, so that the arrangements around the recording elements
 are more free, so that the width of the heater can be increased. In the
 arrangement shown in FIG. 26, by (d), the GND line 5 is disposed adjacent
 the recording element array 2 with the result of lower electric loss.
 FIG. 27 is a perspective view of a liquid jet recording apparatus IJRA to
 which the present invention is applicable. It comprises a lead screw 5005
 which is rotatable by the forward and backward rotation of the driving
 motor 5013 through drive transmission gears 5011 and 5009. A carriage HC
 is engaged with the screw 5004 of the lead screw 5005. The carriage HC is
 provided with an unshown pin. The carriage is reciprocated in the
 directions a and b. A sheet confining plate 5002 urges the sheet to a
 platen 5000 over the carriage movable range. A photo-coupler constituted
 by elements 5007 and 5008 is effective to detect a lever 5006 of the
 carriage HC in the range to switch the rotational direction of the motor
 5013. The position detected by the photocoupler is a home position. A
 supporting member 5016 supports a capping member 5022 for capping the
 front side of the recording head. A sucking means 5015 functions to suck
 the air in the cap to suck out the ink from the recording head through the
 ejection outlets and through an opening 5023 of the cap. A cleaning blade
 5017 is movable toward and away from the recording head. These elements
 are supported on a supporting plate 5018. Other forms of cleaning members
 are applicable. A lever 5012 moves together with movement of a cam 5020
 engaged with the carriage to start the sucking recovery operation. The
 driving force from the driving motor is transmitted by way of known
 transmitting means such as clutch or the like.
 In this structure, the capping, cleaning and sucking operations are enabled
 when the carriage cams to the home position zone by the operation of the
 lead screw 5005. However, such operations may be carried out at different
 timing.
 In this embodiment, the recording head cartridge is carried on the carriage
 HC. The recording head 5030 is separable from the ink container 5031. As
 will be understood from the foregoing description, the size of the
 recording head can be reduced according to the present invention, and
 therefore, the recording head can be easily mounted on the carriage or the
 like. Since the function of converting the recording signal from the
 serial signal to the parallel signal, which has been allotted to the main
 assembly of the printer, is now assigned to the substrate of the recording
 head, the recording apparatus may have a simple structure. Since the
 number of contacts for the signal supply in the recording head is small,
 the wiring is simplified, and the manufacturing steps are simplified In
 addition, the compact and low cost recording apparatus can be provided.
 In the recording head used with such an ink jet recording apparatus, the
 recording head may be exchangeable by the user or may not be exchangeable
 by the user. With the embodiments of the present invention, the number of
 electric contacts is small, and the area occupied by the contacts is
 small. For these reasons, the embodiments are particularly advantageous in
 the case of the recording heads capable of being exchanged by the users.
 FIG. 28 shows a full-line type liquid jet recording apparatus. In this
 embodiment, the number of recording elements corresponding to several tens
 semiconductor chips, the function elements and the driving integrated
 circuits are formed on one substrate. Four of such line recording devices
 are used, corresponding to cyan, yellow, magenta and black color
 printings. It is possible to effect high quality full-color recording. A
 pair of rollers 201A and 201B are provided for feeding the recording
 material R in the sub-scan direction Vs. Full-line type recording means
 202BK, 202Y, 202M and 202C have ink ejecting nozzles over a range
 corresponding to the entire width of the recording material R. They are
 arranged in the order of black, yellow, magenta and cyan from the upstream
 side of the recording material feed. An ejection recovery means 200 is
 faced to the recording means in place of the recording material R during
 the ejection recovery operation, and it includes a cap, ink absorbing
 material, a wiping blade or the like.
 The typical structure and the operational principle are preferably the ones
 disclosed in U.S. Pat. Nos. 4,723,129 and 4,740,796. The principle and
 structure are applicable to a so-called on-demand type recording system
 and a continuous type recording system. Particularly, however, it is
 suitable for the on-demand type because the principle is such that at
 least one driving signal is applied to an electrothermal transducer
 disposed on a liquid (ink) retaining sheet or liquid passage, the driving
 signal being enough to provide such a quick temperature rise beyond a
 departure from nucleation boiling point, by which the thermal energy is
 provided by the electrothermal transducer to produce film boiling on the
 heating portion of the recording head, whereby a bubble can be formed in
 the liquid (ink) corresponding to each of the driving signals. By the
 production, development and contraction of the the bubble, the liquid
 (ink) is ejected through an ejection outlet to produce at least one
 droplet. The driving signal is preferably in the form of a pulse, because
 the development and contraction of the bubble can be effected
 instantaneously, and therefore, the liquid (ink) is ejected with quick
 response. The driving signal in the form of the pulse is preferably such
 as disclosed in U.S. Pat. Nos. 4,463,359 and 4,345,262. In addition, the
 temperature increasing rate of the heating surface is preferably such as
 disclosed in U.S. Pat. No. 4,313,124.
 The structure of the recording head may be as shown in U.S. Pat. Nos.
 4,558,333 and 4,459,600 wherein the heating portion is disposed at a bent
 portion, as well as the structure of the combination of the ejection
 outlet, liquid passage and the electrothermal transducer as disclosed in
 the above-mentioned patents. In addition, the present invention is
 applicable to the structure disclosed in Japanese Laid-Open Patent
 Application No. 123670/1984 wherein a common slit is used as the ejection
 outlet for plural electrothermal transducer, and to the structure
 disclosed in Japanese Laid-Open Patent Application No. 138461/1984 wherein
 an opening for absorbing pressure wave of the thermal energy is formed
 corresponding to the ejecting portion. This is because the present
 invention is effective to perform the recording operation with certainty
 and at high efficiency irrespective of the type of the recording head.
 The present invention is effectively applicable to a so-called full-line
 type recording head having a length corresponding to the maximum recording
 width. Such a recording head may comprise a single recording head and
 plural recording head combined to cover the maximum width.
 In addition, the present invention is applicable to a serial type recording
 head wherein the recording head is fixed on the main assembly, to a
 replaceable chip type recording head which is connected electrically with
 the main apparatus and can be supplied with the ink when it is mounted in
 the main assembly, or to a cartridge type recording head having an
 integral ink container.
 The provisions of the recovery means and/or the auxiliary means for the
 preliminary operation are preferable, because they can further stabilize
 the effects of the present invention. As for such means, there are capping
 means for the recording head, cleaning means therefor, pressing or sucking
 means, preliminary heating means which may be the electrothermal
 transducer, an additional heating element or a combination thereof. Also,
 means for effecting preliminary ejection (not for the recording operation)
 can stabilize the recording operation.
 As regards the variation of the recording head mountable, it may be a
 single corresponding to a single color ink, or may be plural corresponding
 to the plurality of ink materials having different recording color or
 density. The present invention is effectively applicable to an apparatus
 having at least one of a monochromatic mode mainly with black, a
 multi-color mode with different color ink materials and/or a full-color
 mode using the mixture of the colors, which may be an integrally formed
 recording unit or a combination of plural recording heads.
 Furthermore, in the foregoing embodiment, the ink has been liquid. It may
 be, however, an ink material which is solidified below the room
 temperature but liquefied at the room temperature. Since the ink is
 controlled within the temperature not lower than 30.degree. C. and not
 higher than 70.degree. C. to stabilize the viscosity of the ink to provide
 the stabilized ejection in usual recording apparatus of this type, the ink
 may be such that it is liquid within the temperature range when the
 recording signal is the present invention is applicable to other types of
 ink. In one of them, the temperature rise due to the thermal energy is
 positively prevented by consuming it for the state change of the ink from
 the solid state to the liquid state. Another ink material is solidified
 when it is left, to prevent the evaporation of the ink. In either of the
 cases, the application of the recording signal producing thermal energy,
 the ink is liquefied, and the liquefied ink may be ejected. Another ink
 material may start to be solidified at the time when it reaches the
 recording material. The present invention is also applicable to such an
 ink material as is liquefied by the application of the thermal energy.
 Such an ink material may be retained as a liquid or solid material in
 through holes or recesses formed in a porous sheet as disclosed in
 Japanese Laid-Open Patent Application No. 56847/1979 and Japanese
 Laid-Open Patent Application No. 71260/1985. The sheet is faced to the
 electrothermal transducers. The most effective one for the ink materials
 described above is the film boiling system.
 The ink jet recording apparatus may be used as an output terminal of an
 information processing apparatus such as computer or the like, as a
 copying apparatus combined with an image reader or the like, or as a
 facsimile machine having information sending and receiving function.
 As described in the foregoing, the ejection heaters, function elements and
 integrated circuits for selectively driving the function elements in
 response to the serial image data, and electric contacts for the external
 electric connection, are formed on one and the same substrate, and
 therefore, the electrical lead arrangement is not complicated even in a
 high density multi-nozzle structure. Because of the small number of
 contacts, the size of the head is reduced, and the reliability is
 increased. Also, it becomes easier to mount the substrate on the recording
 means or apparatus, and therefore, the cost is reduced.
 In the recording head of the type which can be exchanged by the users, the
 advantages of the small size and the mounting or demounting reliabilities,
 are significant. According to the embodiments of the present invention,
 the fluid loss is reduced, and the utilization factor of the chip area is
 improved. In addition, the reliability of the electric contacts in the
 structure of using plural chips, is enhanced. Furthermore, the time series
 drive control for the purpose of avoiding fluid cross-talk peculiar to the
 ink jet printing, can be made easier.
 According to the present invention, a great number of nozzles such as
 18-several 1000 nozzles can be driven with the small number of electric
 contacts (8 at minimum), and there is no limit for the time shared drive.
 By the cascade connection of plural chips arranged in the longitudinal
 direction of the nozzle arrangement, the density of the recording elements
 can be enhanced significantly. Since the electric contacts do not obstruct
 the other arrangement, the chip may be disposed close to the
 electrothermal transducer element side or the opposite side therefrom.
 Since the electric contacts may be disposed at the opposite sides of the
 electrothermal transducer elements, and the wiring resistance can be
 minimized.
 Since the shift register and or the driver transistor or the like which
 have been disposed conventionally away from the substrate, may be built in
 the substrate, by which the resistance of the leads can be minimized.
 Thus, the energy loss can be reduced. Particularly in the case of the ink
 jet system, the driving current is as large as several hundred mA due to
 the principle of the bubble ejection requiring bubble creation, the
 present invention is advantageous. When the apparatus is driven by
 buttery, the advantageous effects of the present invention are also
 significant.
 While the invention has been described with reference to the structures
 disclosed herein, it is not confined to the details set forth and this
 application is intended to cover such modifications or changes as may come
 within the purposes of the improvements or the scope of the following
 claims.