Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1997-06-25
2001-10-16
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S012000
Reexamination Certificate
active
06302504
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a recording head substrate, a recording head using the recording head substrate, and a recording apparatus using the recording head.
A recording head mounted on a conventional ink-jet recording apparatus has a circuit arrangement, as shown in FIG.
10
. In such printing head, electro-thermal conversion elements (heaters) and a driving circuit therefor are formed on a single substrate using the semiconductor process technique, as disclosed in, e.g., Japanese Patent Laid-Open No. 5-185594.
Referring to
FIG. 10
, reference numeral
401
denotes electro-thermal conversion elements (heaters) for generating heat energy;
451
, power transistors each for supplying a desired current to the corresponding heater
401
;
502
, a shift register for temporarily storing image data indicating whether or not currents are supplied to the individual heaters
401
to eject ink from the nozzles of the recording head;
503
, an image data input terminal for serially inputting image data (DATA) for turning on/off the heaters
401
;
504
, an input terminal provided to the shift register
502
to receive transfer clock pulses (CLK);
501
, latch circuits for storing image data (DATA) corresponding to the heaters
401
in units of heaters;
505
, a latch signal input terminal for inputting a latch timing signal (LT) to the latch circuits
501
;
506
, switches for determining the supply timings of currents to the heaters
401
;
452
, a power supply line for applying a predetermined voltage to the heaters to supply currents; and
453
, a GND line into which currents that flowed through the heater
401
and the power transistor
451
flow.
Note that the number of bits of image data stored in the shift register
502
, the number of power transistors
451
, and the number of heaters
401
are equal to each other.
FIG. 11
is a timing chart of various signals for driving the recording head driving circuit shown in FIG.
10
.
The operation of the recording head driving circuit shown in
FIG. 10
will be described below with reference to
FIG. 11. A
number of transfer clock pulses (CLK) corresponding to the number of bits of image data stored in the shift register
502
is input to the transfer clock input terminal
504
. In this case, assume that data is transferred to the shift register
502
in synchronism with the leading edge of the transfer clock pulses (CLK), and image data (DATA) for turning on/off the heaters
401
is input from the image data input terminal
503
.
Since the number of bits of image data stored in the shift register
502
, the number of heaters
401
, and the number of power transistors
451
for current driving are equal to each other, transfer clock pulses (CLK) corresponding to the number of heaters
401
are input to transfer the image data (DATA) to the shift register
502
. Thereafter, a latch signal (LT) is supplied to the latch signal input terminal
505
to latch image data corresponding to the heaters
401
in the latch circuits
501
.
Thereafter, when the switches
506
are set in the “ON” state for an appropriate period of time, currents are supplied to the power transistors
451
and heaters
401
via the power supply line
451
in correspondence with the ON durations of the switches
506
, and the currents then flow into the GND line
453
. At this time, each heater
401
generates heat required for ejecting ink, and ink corresponding to the image data (DATA) is ejected from the nozzles of the recording head.
The above-mentioned arrangement is conventionally known. Furthermore, a recording head having an arrangement shown in
FIG. 12
, as an improved arrangement of
FIG. 10
, is also proposed.
Referring to
FIG. 12
, reference numeral
410
denotes nMOS field effect transistors (FETs) serving as power transistors for supplying desired currents to the heaters.
When this circuit arrangement is compared with that shown in
FIG. 10
, the arrangement shown in
FIG. 10
uses Darlington-connected npn transistors as each power transistor. In this arrangement, a logic circuit such as a shift register, a latch, or the like normally uses a CMOS gate, and a BiCMOS process is used to form npn transistors simultaneously with such gate. However, the BiCMOS process requires a large number of masks, and results in high cost. In view of this problem, as shown in
FIG. 12
, when nMOS transistors are used in place of npn transistors, the power transistors can be formed using the same process (CMOS process) as that of the logic circuit, thus allowing the manufacture of a recording head with relatively low cost.
An ink-jet printing method (i.e., a printing method by ejecting liquid) can realize high speed printing and has negligibly small noise produced upon printing, and has received a lot of attention recently since it can attain printing without requiring any special process, i.e., a so-called fixing process to a normal paper sheet.
Among such ink-jet printing methods, the liquid-jet printing methods described in, e.g., Japanese Patent Laid-Open No. 54-51834 and DOLS No. 2843064 have features different from other liquid-jet printing methods in that they acquire a driving force for ejecting a droplet by applying heat energy to the liquid.
More specifically, the printing method disclosed in the above references is characterized in that the liquid that received the applied heat energy undergoes changes in state accompanying an abrupt increase in volume and is ejected by an effect obtained based on the changes in state from each orifice at the distal end of a recording head to form a flying droplet, and the droplet becomes attached to a printing medium to attain recording.
Especially, the liquid-jet printing method disclosed in DOLS No. 2843064 is very effectively applied to a so-called drop-on demand printing method, and can easily realize a full-line type, high-density, multi-orifice recording head. For this reason, high-speed printing of a high-resolution, high-quality image can be achieved.
The recording head that uses the above-mentioned printing method is built by a recording head substrate which comprises liquid ejection portions having orifices formed to eject a liquid, heat applying portions which communicate with the orifices to apply heat energy for ejecting a droplet to the liquid, liquid channels including the heat applying portions, and substrate of recording head including electro-thermal conversion elements (heating elements) as means for generating heat energy.
In recent years, on such substrate, not only a plurality of heating elements are formed, but also logic circuits such as a plurality of drivers for driving the individual heating elements, a shift register for temporarily storing image data having the same number of bits as the number of heating elements to parallelly transfer the image data, serially input from a recording apparatus, to the drivers, latch circuits for temporarily latching data output from the shift register, and the like can be mounted on the single substrate.
FIG. 19
is a block diagram showing the logic circuit arrangement of a conventional recording head having N heating elements (print elements).
Referring to
FIG. 19
, reference numeral
700
denotes a substrate;
701
, heating elements;
702
, power transistors;
703
, an N-bit latch circuit; and
704
, an N-bit shift register. Reference numeral
715
denotes a sensor for monitoring the resistances of the heating elements
701
or the temperature of the substrate
700
, or a heater for keeping the substrate
700
at a desired temperature. A plurality of such sensors and heaters may be mounted, and the sensor and heater may be integrally arranged. Reference numerals
705
to
714
, and
716
denote input/output pads. Of these input/output pads, reference numeral
705
denotes a clock input pad for inputting clock pulses (CLK) for operating the shift register
704
;
706
, an image data input pad for serially inputting image data (DATA);
707
, a latch input pad for inputting a latch clock pulses (LTCLK) for controlling the latch ci
Furukawa Tatsuo
Imanaka Yoshiyuki
Kasamoto Masami
Mochizuki Muga
Mori Toshihiro
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stewart Jr. Charles W.
LandOfFree
Recording head and recording apparatus using the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Recording head and recording apparatus using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recording head and recording apparatus using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2583149