EP0505154B1 - Temperatursteuerung für thermischen Tintenstrahlaufzeichnungskopf - Google Patents

Temperatursteuerung für thermischen Tintenstrahlaufzeichnungskopf Download PDF

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Publication number
EP0505154B1
EP0505154B1 EP92302313A EP92302313A EP0505154B1 EP 0505154 B1 EP0505154 B1 EP 0505154B1 EP 92302313 A EP92302313 A EP 92302313A EP 92302313 A EP92302313 A EP 92302313A EP 0505154 B1 EP0505154 B1 EP 0505154B1
Authority
EP
European Patent Office
Prior art keywords
temperature
head
recording head
ink
ejection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92302313A
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English (en)
French (fr)
Other versions
EP0505154A2 (de
EP0505154A3 (en
Inventor
Naoji C/O Canon Kabushiki Kaisha Otsuka
Hiromitsu C/O Canon Kabushiki Kaisha Hirabayashi
Kentaro C/O Canon Kabushiki Kaisha Yano
Kiichiro C/O Canon Kabushiki Kaisha Takahashi
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Canon Inc
Original Assignee
Canon Inc
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Filing date
Publication date
Priority claimed from JP4044773A external-priority patent/JP2974487B2/ja
Application filed by Canon Inc filed Critical Canon Inc
Priority to EP00200209A priority Critical patent/EP0997287B1/de
Publication of EP0505154A2 publication Critical patent/EP0505154A2/de
Publication of EP0505154A3 publication Critical patent/EP0505154A3/en
Application granted granted Critical
Publication of EP0505154B1 publication Critical patent/EP0505154B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04528—Control methods or devices therefor, e.g. driver circuits, control circuits aiming at warming up the head
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04531—Control methods or devices therefor, e.g. driver circuits, control circuits controlling a head having a heater in the manifold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/0454—Control methods or devices therefor, e.g. driver circuits, control circuits involving calculation of temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04553—Control methods or devices therefor, e.g. driver circuits, control circuits detecting ambient temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04563—Control methods or devices therefor, e.g. driver circuits, control circuits detecting head temperature; Ink temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/0458—Control methods or devices therefor, e.g. driver circuits, control circuits controlling heads based on heating elements forming bubbles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04588—Control methods or devices therefor, e.g. driver circuits, control circuits using a specific waveform
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04591—Width of the driving signal being adjusted
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04598—Pre-pulse
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/165—Preventing or detecting of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
    • B41J2/16517—Cleaning of print head nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2002/14379—Edge shooter

Definitions

  • the present invention relates to an ink-jet recording apparatus for performing a recording operation by ejecting an ink from a recording head to a recording medium, and a temperature control method of the ink-jet recording apparatus.
  • Recording apparatuses such as printers, copying machines, facsimile apparatuses, and the like record an image consisting of a dot pattern on a recording medium such as a paper sheet or a plastic thin plate on the basis of image information.
  • the recording apparatuses can be classified into ink-jet type, wire-dot type, thermal type, laser beam type, and the like according to their recording systems.
  • an ink-jet type apparatus (ink-jet recording apparatus) causes a recording head to eject a flying ink (recording liquid) droplet from an ejection port thereof, and attaches the ink droplet to a recording medium to perform a recording operation.
  • the above-mentioned ink-jet recording apparatus is known.
  • the ink-jet recording apparatus since a recording operation is performed by ejecting an ink from a recording head, stabilization control of an ink ejection operation, and an ink ejection quantity, which is necessary for satisfying the above-mentioned requirements, is largely influenced by the temperature of the recording head.
  • the conventional ink-jet recording apparatus adopts so-called closed-loop control, i.e., a method wherein an expensive temperature sensor is provided to a recording head unit, and based on the detected temperature of the recording head, the temperature of the recording head is controlled within a desired range or ejection restoration processing is controlled.
  • a heater for the temperature control a heater member joined to the recording head unit, or an ejection heater is used in an ink-jet recording apparatus, which forms a flying droplet by utilizing a heat energy to perform recording, i.e., in an apparatus for ejecting an ink droplet by the growth of a bubble caused by film boiling of an ink.
  • the ejection heater When the ejection heater is used, it must be energized to a temperature as low as a bubble non-forming temperature.
  • an exchangeable cartridge type head in which a head and an ink tank are integrated, is expected to become increasingly popular in future.
  • the exchangeable cartridge type head is also expected to become popular from the viewpoint of maintenance due to the popularity of home/personal use wordprocessors, personal computers, and facsimile apparatuses.
  • a diode sensor for detecting the temperature of the recording head in the same process from the viewpoint of a decrease in cost. Since the diode sensor suffers from a variation in the manufacture, it does not have precision as high as a temperature sensor as a selected product. Thus, the surrounding temperatures measured by diode sensors in different manufacturing lots sometimes have a difference of 15°C or more.
  • exchangeable heads are expendable supplies, a user repetitively attaches/detaches the head from the main body. For this reason, contacts of the main body apparatus side are always exposed.
  • a temperature measurement circuit Since the output from a temperature sensor is directly supplied from the exchangeable head to a circuit on a printed circuit board of the main body through a carriage and flexible wiring lines, a temperature measurement circuit is very weak against electrostatic noise. This weak point is enhanced since the housing of a compact, portable printer cannot have a sufficient shield effect.
  • electrostatic shields and parts as a countermeasure against electrostatic noise must be added for only one temperature sensor, and a compact structure, a decrease in cost, and quality are considerably damaged.
  • the object of temperature detection of the recording head is to control the temperature of the recording head within a desired range, and to perform stabilization control of the recording ink ejection operation, and the ejection quantity, as described above. More specifically, temperature detection of the recording head means detection of the ink temperature on the ejection heater in a strict sense. However, since it is difficult to directly detect the ink temperature on the ejection heater, the temperature sensor is attached near the heater (or nozzle) (the mounting position of the temperature sensor will be described in detail later). In an ink-jet recording apparatus, since the heat conduction speed of a heater board is lower than the speed of a change in ink temperature near the ejection heater, a time delay from an actual temperature is generated even if the temperature of the head is continuously detected.
  • a temperature may be erroneously detected due to a thermal flow or electrical noise input to the temperature sensor.
  • a method of averaging several detection values of the head temperature, and determining an average value as a current head temperature is adopted.
  • the following problems are posed:
  • the present invention has been made in view of the above-mentioned problems, and has as a concern to provide a recording apparatus, which can detect the temperature of a recording head without arranging a temperature sensor in the recording head.
  • Canadian Patent Specification No. CA-A-2025506 discloses a recording head for ejecting ink from an ejection port using heat energy in response to a driving signal.
  • a control unit controls the energy supplied to a heating means for heating the head on the basis of measured ambient temperature.
  • a surrounding temperature sensor for measuring the surrounding temperature is provided in the main body of the apparatus side, and a change in temperature of the head from the past to the present time is presumed and that from the present time to the future is predicted both by calculation processing, so that optimal temperature control can be performed without arranging a temperature sensor in the actual head, which has a correlation with the temperature.
  • a change in temperature of the head is presumed or predicted by evaluating it using a matrix which is calculated in advance within a range of a thermal time constant of the head and an applicable energy.
  • Fig. 1 is a perspective view showing the arrangement of an ink-jet recording apparatus IJRA, in which the present invention is suitably practiced or applied.
  • a recording head (IJH) 5012 is coupled to an ink tank (IT) 5001.
  • IJC integrated exchangeable cartridge
  • a carriage (HC) 5014 is used for mounting the cartridge (IJC) to a printer main body, and is scanned in the sub-scan direction along a guide 5003.
  • a platen roller 5000 scans a printing medium P in the main scan direction.
  • a temperature sensor 5024 measures the surrounding temperature in the apparatus. Note that the carriage 5014 is connected to a printed circuit board (not shown) comprising electrical circuits (e.g., the temperature sensor 5024) for controlling a printer through a flexible cable (not shown) for supplying a driving signal pulse current and a head temperature control current to the recording head 5012.
  • Fig. 2 shows the exchangeable cartridge.
  • the cartridge has a nozzle portion 5029 for ejecting an ink droplet.
  • the ink-jet recording apparatus IJRA with the above arrangement will be described in detail below.
  • the carriage HC is engaged with a spiral groove 5004 of a lead screw 5005, which is rotated through driving force transmission gears 5011 and 5009 upon normal or reverse rotation of a driving motor 5013.
  • the carriage HC has a pin (not shown), and is reciprocally moved in directions indicated by arrows a and b.
  • a paper pressing plate 5002 presses a paper sheet against the platen 5000 along a carriage moving direction.
  • Photocouplers 5007 and 5008 serve as a home position detection means for confirming the presence of a lever 5006 of the carriage HC in a corresponding region, and, e.g., switching the rotational direction of the motor 5013.
  • a member 5016 supports a cap member 5022 for capping the front surface of the recording head.
  • a suction means 5015 draws the interior of the cap by vacuum suction, and performs a suction restoration operation of the recording head 5012 through an inner cap opening 5023.
  • a member 5019 allows forward/backward movement of a cleaning blade 5017.
  • the member 5019 and the cleaning blade 5017 are supported on a main body support plate 5018.
  • the blade of this embodiment is not limited to the cleaning blade 5017, but may employ a known cleaning blade.
  • a lever 5021 is used for starting a suction operation of a suction restoration operation. The lever 5021 is moved upon movement of a cam 5020 engaged with the carriage HC, and is subjected to movement control based on a driving force from the driving motor through a known transmission means (by, e.g., switching clutches).
  • capping, cleaning, and suction restoration operations can be performed at their corresponding positions by operation of the lead screw 5005 when the carriage HC reaches a home position region.
  • the embodiment is not limited to this as long as desired operations are performed at known timings.
  • Fig. 3 shows in detail the recording head 5012.
  • a heater board 5100 formed in a semiconductor manufacturing process is arranged on the upper surface of a support member 5300.
  • a temperature control heater (temperature rise heater) 5110, formed in the same semiconductor manufacturing process, for holding and controlling the temperature of the recording head 5012 is arranged on the heater board 5100.
  • a wiring board 5200 is arranged on the support member 5300.
  • the wiring board 5200, the temperature control heater 5110, and an ejection (main) heater 5113 are connected through wiring lines (not shown) by, e.g., wire bonding.
  • the temperature control heater 5110 may be prepared by adhering a heater member formed in a process different from the heater board 5100 onto the support member 5300, or the like.
  • a bubble 5114 is generated by heating by the ejection heater 5113.
  • An ink is ejected as an ink droplet 5115.
  • the head has a common ink chamber 5112 through which an ink to be ejected is flowed into the recording head.
  • Fig. 4 is a schematic view of the ink-jet recording apparatus to which the present invention is applicable.
  • each ink-jet cartridge 8a has an ink tank portion in its upper portion, and a recording head 8b (not shown) in its lower portion, and also has a connector for receiving a signal for driving the recording head 8b.
  • a carriage 9 can align and mount four cartridges (which respectively store inks of different colors, e.g., black, cyan, magenta, yellow, and the like).
  • the carriage has a connector holder for supplying signals for driving the corresponding recording heads, and the holder is connected to each recording heads 8b.
  • the apparatus includes a scan rail 9a, extending in the main scan direction of the carriage 9, for slidably supporting the carriage 9, a driving belt 9c for transmitting a driving force for reciprocating the carriage 9, a pair of convey rollers 10c and 10d, arranged in front of and behind the recording position of the recording head, for clamping and conveying a recording medium, and a recording medium 11 such as a paper sheet, which is urged against a platen (not shown) for regulating the recording surface of the recording medium 11 to be flat.
  • a scan rail 9a extending in the main scan direction of the carriage 9, for slidably supporting the carriage 9, a driving belt 9c for transmitting a driving force for reciprocating the carriage 9, a pair of convey rollers 10c and 10d, arranged in front of and behind the recording position of the recording head, for clamping and conveying a recording medium, and a recording medium 11 such as a paper sheet, which is urged against a platen (not shown) for regulating the recording surface of the recording medium 11 to be
  • the recording heads 8b of the ink-jet cartridges 8a mounted on the carriage 9 extend downward from the carriage 9, and are located between the recording medium convey rollers 10c and 10d, so that the ejection port forming surface of each recording head unit opposes parallel to the recording medium 11 urged against the guide surface of the platen (not shown).
  • the driving belt 9c is driven by a main scan motor 63, and the pair of convey rollers 10c and 10d are driven by a sub-scan motor 64 (not shown).
  • a restoration system unit 400 is arranged at the home position side on the left side in Fig. 1.
  • the restoration system unit 400 includes cap units 300 arranged in correspondence with the plurality of ink-jet cartridges 8a each having a recording head 8b.
  • the cap units 300 are slidable in the right-and-left direction in Fig. 4, and are vertically movable upon movement of the carriage 9.
  • the cap units 300 are coupled to the corresponding recording heads 8b to cap them, thus preventing an ejection error, which occurs when an ink in the ejection port of each recording head 8b becomes highly viscous and sticks to the port upon evaporation.
  • the restoration system unit 400 also includes a pump unit 500 communicating with the cap units 300.
  • the pump unit 500 is used for generating a negative pressure in suction restoration processing, which is performed by coupling the cap units 300 and the recording heads 8b when the recording heads 8b suffer from an ejection error.
  • the restoration system unit 400 includes a blade 401 as a wiping member formed of an elastic member such as rubber, and a blade holder 402 for holding the blade 401.
  • Reference numeral 403 denotes an absorber.
  • the four ink cartridges mounted on the carriage 9 use a black ink (to be abbreviated to as K hereinafter), a cyan ink (to be abbreviated to as C hereinafter), a magenta ink (to be abbreviated to as M hereinafter), and a yellow ink (to be abbreviated to as Y hereinafter), and inks overlap in this order.
  • K black ink
  • C cyan ink
  • M magenta ink
  • Y yellow ink
  • black can be realized by overlapping three colors C, M, and Y, since color development of black at that time is poor, and it is difficult to precisely overlap three colors, a chromatic color edge is undesirably formed, and the ink ejection density per unit time becomes too high. Thus, only black is separately ejected (black ink is used).
  • the recording apparatus includes a CPU 60, a program ROM 61 for storing a control program executed by the CPU 60, an EEPROM 62 for storing various data, the main scan motor 63 for moving the recording heads, and the sub-scan motor 64 for conveying a recording sheet.
  • the sub-scan motor 64 is also used in a suction operation by a pump.
  • the apparatus also includes a wiping solenoid 65, a paper feed solenoid 66 used in paper feed control, a cooling fan 67, a paper width detector LED 68, which is turned on in a paper width detection operation, a paper width sensor 69, a paper flit sensor 70, a paper feed sensor 71, a paper eject sensor 72, a pump position sensor 73 for detecting the position of a suction pump, a carriage HP sensor 74 for detecting the home position of the carriage, a door open sensor 75 for detecting an open/closed state of a door, and a temperature sensor 76 for detecting the surrounding temperature of the apparatus.
  • the apparatus includes a gate array 78 for performing supply control of recording data to the heads of four colors, a head driver 79 for driving the head, the ink cartridges 8a for four colors, and the recording heads 8b for four colors.
  • Fig. 5 shows only the cartridge 8a and the head 8b for black (Bk).
  • the ink cartridge 8a has a remaining ink sensor 8f for detecting the remaining quantity of an ink.
  • the head 8b has a main heater 8c for ejecting an ink, a sub-heater 8d for performing temperature control of the head, and a ROM 854 for storing various data for the head.
  • Fig. 6 shows a heater board (H.B) 853 of the head used in this embodiment.
  • An ejection unit array 8g in which the temperature control (sub) heaters 8d and the ejection (main) heaters 8c are arranged, and driving elements 8h are formed on a single board to have the positional relationship shown in Fig. 6. Since these elements are arranged on the single board, the head temperature can be efficiently detected and controlled. Thus, the head can be further miniaturized, and the manufacturing processing can be further simplified.
  • Fig. 6 also shows the positional relationship of an outer shielding surface 8f of a top plate for separating the H.B into a region filled with an ink, and a region not filled with an ink.
  • a surrounding temperature sensor for measuring the surrounding temperature is provided to a main body side to detect a change in head temperature from the past to the present time by calculation processing, so that optimal temperature control can be performed without arranging a head temperature sensor, which has a correlation with the head temperature.
  • a change in head temperature is presumed by evaluating it using a matrix which is calculated in advance within a range of the thermal time constant of the head and the applicable energy applied to the head.
  • the thermal time constant or thermal capacity of the recording head is essentially a ratio determined by the quantity of heat required to raise the temperature of the head a specified amount.
  • the head is controlled by a divided pulse width modulation driving method (PWM driving method) for a heater (sub-heater) for increasing the temperature of the head, and an ejection heater.
  • PWM driving method for a heater (sub-heater) for increasing the temperature of the head
  • ejection heater for increasing the temperature of the head
  • PWM driving method when a difference from a temperature control target value is large, the temperature is increased to a temperature near the target value using the sub-heater, and the remaining temperature difference is controlled by PWM ejection quantity control, so that the ejection quantity can become constant.
  • PWM in one line can be realized without arranging a temperature sensor in a head, as described above.
  • Fig. 7 is a view for explaining divided pulses according to the embodiment of the present invention.
  • VOP represents a driving voltage
  • P1 represents the pulse width of the first pulse (to be referred to as a pre-heat pulse hereinafter) of a plurality of divided heat pulses
  • P2 represents the interval time
  • P3 represents the pulse width of the second pulse (to be referred to as a main heat pulse hereinafter).
  • T1, T2, and T3 represent times for determining P1, P2, and P3.
  • the driving voltage VOP corresponds to a kind of electrical energy necessary for causing an electrothermal converting element applied with this voltage to generate a heat energy in an ink in an ink channel constituted by the heater board and the top plate.
  • the value of the driving voltage VOP is determined by the area, resistance, and film structure of the electrothermal converting element, and the channel structure of the recording head.
  • pulses are sequentially applied to have the widths P1, P2, and P3.
  • the pre-heat pulse is a pulse for mainly controlling the ink temperature in the ink channel, and plays an important role in the ejection quantity control of the present invention.
  • the pre-heat pulse width is set to be a value, which does not cause a bubble forming phenomenon in an ink by a heat energy generated by the electrothermal converting element upon application of the pre-heat pulse.
  • the interval time is set to form a predetermined time interval, so that the pre-heat pulse and the main heat pulse do not interfere with each other, and to obtain a uniform temperature distribution of an ink in the ink channel.
  • the main heat pulse forms a bubble in an ink in the ink channel to eject the ink from the ejection port.
  • the pulse width P3 of the main heat pulse is determined by the area, resistance, and film structure of the electrothermal converting element, and the ink channel structure of the recording head.
  • Figs. 8A and 8B are respectively a schematic longitudinal sectional view and a schematic front view showing an arrangement along an ink channel of a recording head to which the present invention can be applied.
  • each electrothermal converting element (ejection heater) 21 generates heat upon application of the above-mentioned divided pulses.
  • the electrothermal converting element 21 is arranged on a heater board together with an electrode wiring line, and the like for applying the divided pulses to the converter.
  • the heater board is formed of a silicon layer 29, and is supported by an aluminum plate 31 constituting the board of the recording head.
  • the ink channel 23, and a common ink chamber 25 for supplying an ink to the channel are defined.
  • Ejection ports 27 are formed in the top plate 32, and communicate with the ink channel 23.
  • Fig. 9 is a graph showing pre-heat pulse dependency of the ejection quantity.
  • the ejection quantity Vd is increased to have linearity when the pulse width P1 falls within a range between 0 and P1LMT, and its change loses linearity when the pulse width P1 exceeds P1LMT.
  • the ejection quantity Vd is saturated and becomes maximum at a pulse width P1MAX.
  • the range up to the pulse width P1LMT in which a change in ejection quantity Vd shows linearity with respect to a change in pulse width P1
  • P1LMT 1.87 ⁇ s
  • P1MAX 2.1 ⁇ s
  • the ejection quantity Vd becomes smaller than VMAX.
  • This phenomenon occurs for the following reason. That is, when the pre-heat pulse having a pulse width within the above-mentioned range is applied, a very small bubble (in a state immediately before film boiling) is formed on the electrothermal converting element, the next main heat pulse is applied before this bubble disappears, and the very small bubble disturbs bubble formation by the main heat pulse, thus decreasing the ejection quantity.
  • This region will be referred to as a pre-bubble region hereinafter, and it is difficult to perform ejection quantity control using the pre-heat pulse in this region.
  • Another factor for determining the ejection quantity of the ink-jet recording head is the temperature of the recording head (ink temperature).
  • ejection quantity control according to the present invention can be performed using the relationships shown in Figs. 9 and 10.
  • a temperature correction timer is reset and set (S110). Then, the temperature of a temperature sensor (to be referred to as a reference thermistor hereinafter) on a main body printed circuit board (to be referred to as a PCB hereinafter) is read (S120), thereby detecting the surrounding temperature.
  • a temperature sensor to be referred to as a reference thermistor hereinafter
  • PCB main body printed circuit board
  • a time elapsed from the ON operation of the power supply is read from the temperature correction timer (S130) to refer to a temperature correction table (Table 1), thus obtaining an accurate surrounding temperature from which the influence of the heat generating member is eliminated (S140).
  • Temperature Correction Timer (min) 0 to 2 2 to 5 5 to 15 15 to 30 Over 30 Correction Value (°C) 0 -2 -4 -6 -7
  • a current head chip temperature ( ⁇ ) is presumed with reference to a temperature presumption table (Fig. 14), and the control waits for input of a print signal.
  • the presumption of the current head chip temperature ( ⁇ ) is performed by adding, to the surrounding temperature obtained in step S140, a value determined by a matrix of temperature differences between the head temperature and the surrounding temperature with respect to the applied energy (power ratio) to the head, thereby updating the surrounding temperature.
  • a matrix value 0 thermal equilibrium
  • the temperature presumption table shown in Fig. 14 is a matrix table showing temperature rise characteristics per unit time, which are determined by the thermal time constant of the head, and the energy applied to the head.
  • the matrix value becomes large, while when the temperature difference between the head temperature and the surrounding temperature becomes large, since a thermal equilibrium state can be easily established, the matrix value is decreased.
  • the thermal equilibrium state is established when the applied energy is equal to the radiation energy.
  • a print target temperature ( ⁇ ) of the head chip which allows an optimal driving operation at the current surrounding temperature, is obtained with reference to a target (driving) temperature table (Table 2) (S170).
  • Table 2 the reason why the target temperature varies depending on the surrounding temperature is that even when the temperature on the silicon heater board of the head is controlled to a given temperature, since the temperature of an ink flowing into the head is low, and the thermal time constant is large, the temperature of a system around the head chip becomes consequently low if this temperature is considered as an average temperature. For this reason, as the surrounding temperature becomes lower, the target temperature of the silicon heater board of the head must be increased.
  • step S190 an ON time (t) of the sub-heater before the print operation for the purpose of decreasing the difference ( ⁇ ) is obtained with reference to a sub-heater control table (Table 3), and the sub-heater is turned on (S300). This is a function of increasing the temperature of the entire head chip by the sub-heater when the presumed temperature of the head and the target temperature have a difference therebetween at the beginning of the print operation. Thus, the temperature of the entire head chip can be set to be close to the target temperature as much as possible.
  • the sub-heater After the sub-heater is turned on for the above setting time, the sub-heater is turned off, and the current chip temperature ( ⁇ ) is presumed with reference to the current temperature presumption table (Fig. 14). Then, a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the head chip temperature ( ⁇ ) is calculated (S320), and a PWM value at the beginning of the print operation is obtained from a PWM value determination table (Table 4) according to the difference ( ⁇ ) (S330). It is difficult to cause the chip temperature to precisely approach the target temperature even using the sub-heater, and furthermore, it is very difficult to perform temperature correction in one line by the sub-heater.
  • the ejection quantity is corrected by the PWM method in accordance with the remaining difference from the target value.
  • the above-mentioned value P1 is increased to increase the ejection quantity.
  • the PWM value is optimized every time a predetermined area is printed in a one-line print operation.
  • one line is divided into 10 areas, and an optimal PWM value is set for each area. More specifically, this operation is performed as follows.
  • the print operation of an n-th area is performed (S360), and upon completion of the print operation of the 10th area, the flow returns to step S130 to read the temperature of the reference thermistor. If n ⁇ 10, and areas to be printed remain in one line (S370), the flow advances to step S380 to obtain a change in temperature of the head caused by the print operation of the immediately preceding area.
  • a head chip temperature ( ⁇ ) upon completion of the print operation of the n-th area (immediately before the print operation of an (n+1)-th area) is obtained with reference to the current temperature presumption table (Fig. 14) (S380).
  • a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the head chip temperature ( ⁇ ) is calculated, and a PWM value upon printing of the (n+1)-th area is set with reference to the PWM value determination table (Table 4) according to the difference ( ⁇ ) (S390, S400, S410). Thereafter, the flow returns to step S350.
  • the head chip temperature ( ⁇ ) can gradually approach the print target temperature ( ⁇ ). Even if a large temperature difference is present between the head chip temperature ( ⁇ ) and the print target temperature ( ⁇ ) like in an early period after power-ON, since PWM control is performed within one line, an actual ejection quantity can be controlled like that at the print target temperature, and high quality can be realized.
  • the reason why this embodiment does not simply use the number of dots (print duty) is that an energy to be supplied to a head chip varies depending on different PWM values even if the number of dots remains the same. Since the concept of "power ratio" is used, the same table can be used even when the sub-heater is turned on.
  • Stabilization control of the ejection operation/ejection quantity of the head is attained by controlling the following two points.
  • a recording signal sent through an external interface is stored in a reception buffer 78a of the gate array 78.
  • the data stored in the reception buffer 78a is expanded to a binary signal (0, 1) indicating "ejection/no ejection", and the binary signal is transferred to a print buffer 78b.
  • the CPU 60 can refer to the recording signal from the print buffer 78b as needed.
  • two line duty buffers 78c are prepared. One line upon recording is divided at equal intervals (into, e.g., 10 areas), and the print duty (ratio) of each area is calculated and stored in the duty buffers.
  • the "line duty buffer 78c1" stores print duty data in units of areas of the currently printing line.
  • the “line duty buffer 78c2” stores print duty data in units of areas of a line next to the currently printing line.
  • the CPU 60 can refer to the print duty data in units of areas of the currently printing line and the next line any time, as needed.
  • the CPU 60 refers to the line duty buffers 78c during the above-mentioned temperature prediction control to obtain the print duties of the areas. Therefore, a calculation load on the CPU 60 can be reduced.
  • a difference between the surrounding temperature and the head temperature is calculated to check if the heating operation of the sub-heater immediately before printing is necessary.
  • Fig. 15B since the head temperature is not largely shifted from the target temperature, the heating operation of the sub-heater is not performed (Fig. 15D).
  • the head temperature (Fig. 15B) immediately before printing of an area A1 is presumed, and the print operation is performed using a PWM value (Fig. 15C) for the area A1 according to the difference.
  • a PWM value Fig. 15C
  • a difference between the surrounding temperature and the head temperature is calculated to check if the heating operation of the sub-heater immediately before printing is necessary.
  • the head temperature is largely shifted from the target temperature, it is determined that the heating operation of the sub-heater is necessary, and the heating operation of the sub-heater is performed (Fig. 16D).
  • a head temperature upon completion of the heating operation of the sub-heater and immediately before printing of an area A1 (Fig. 16B) is presumed. Since it is presumed that the head temperature exceeds the target temperature, a minimum value is assigned to the PWM value (Fig. 16C) upon printing of the area A1.
  • the heating operation of the sub-heater can increase the temperature in an early period of the heating operation, since the difference between the head temperature and the target temperature is large, it can be easily presumed that the head temperature is decreased below the reference temperature upon completion of printing. Therefore, the head temperature immediately after the sub-heater is turned on is intentionally set to exceed the target temperature.
  • the minimum value is assigned to the PWM value of the area A1 to perform the print operation.
  • the duty (100%) of the area A1 is high, it is presumed that the temperature immediately before printing of an area A2 is not decreased below the target temperature, and a minimum PWM value is set for the area A2.
  • the head temperature is gradually decreased to a temperature below the target temperature, and optimal PWM values are set to perform the print operations (in this case, since the print duties are 0, no actual print operations are performed). Thereafter, the heating operation of the sub-heater and the actual print operations are performed, while setting the PWM values of the areas in the same manner as in Figs. 15A to 15E.
  • a difference between the cases in Figs. 15A to 15E and Figs. 16A to 16E is that the ejection quantity does not exceed the ejection quantity (Fig. 15E) at the target temperature in the former case, while the ejection quantity sometimes exceeds the ejection quantity (Fig. 16E) at the target temperature in the latter case.
  • a negative PWM value may be provided.
  • double-pulse PWM control is used to control the ejection quantity.
  • single-pulse PWM or PWM using triple pulses or more may be used.
  • the scanning speed of the carriage may be controlled, or the scanning start timing of the carriage may be controlled.
  • the number of divided areas (10 areas) in one line, and constants such as the temperature prediction cycle (0.1 sec), and the like used in this embodiment area merely examples, and the present invention is not limited to these.
  • step S190 Fig. 11
  • step S190 an ON time (t) of a sub-heater before printing for the purpose of decreasing the difference ( ⁇ ) is obtained with reference to a sub-heater control table (Table 3). Thereafter, the sub-heater is turned on, as shown in Fig. 21 (S200). After the sub-heater is turned on for the setting time, the sub-heater is turned off, a current chip temperature ( ⁇ ) (chip temperature immediately before printing) is presumed with reference to a current temperature presumption table (Fig. 14) (S210).
  • ⁇ current chip temperature immediately before printing
  • a difference ( ⁇ ) between a print target temperature ( ⁇ ) and the current head chip temperature ( ⁇ ) is calculated, and a PWM value is obtained with reference to a PWM value determination table (Table 4) (S220, S230).
  • a one-line print operation is performed according to the obtained PWM value (S240), and after the print operation, the flow returns to step S120 to read the temperature of a reference thermistor.
  • the head chip temperature ( ⁇ ) gradually approaches the print target temperature ( ⁇ ). Even if a large temperature difference is present between the head chip temperature ( ⁇ ) and the print target temperature ( ⁇ ) like in an early period after power-ON, since PWM control is performed in units of lines, an actual ejection quantity can be controlled to approach that at the print target temperature, and high quality can be realized.
  • double-pulse PWM control is used to control the ejection quantity.
  • single-pulse PWM or PWM using triple pulses or more may be used.
  • the scanning speed of the carriage may be controlled, or the scanning start timing of the carriage may be controlled.
  • a method of presuming the current temperature based on the print ratio (to be referred to as a print duty hereinafter), and controlling a restoration sequence for stabilizing ejection will be explained below.
  • the print duty is equal to a power ratio.
  • the current head temperature is presumed from the print duty like in the first embodiment, and a suction condition of a suction means is changed according to the presumed temperature of the head.
  • the control of the suction condition is made based on the suction pressure (initial piston position) and the suction quantity (a change in volume or a vacuum hold time).
  • Fig. 17 shows head temperature dependency of the vacuum hold time and the suction quantity.
  • the suction quantity can be controlled by the vacuum hold time during a given period, the suction quantity does not depend on the vacuum hold time outside the given period. Since the suction quantity is influenced by the head temperature presumed from the print duty, the vacuum hold time is changed according to the head presumed temperature. In this manner, even when the head temperature changes, the ejection quantity can be maintained to be constant (an optimal quantity), thus stabilizing ejection.
  • a decrease in head temperature upon a suction operation is presumed.
  • an ink at a high temperature is discharged by suction, and a new low-temperature ink is supplied from an ink tank.
  • the high-temperature head is cooled by the supplied ink.
  • Table 5 shows differences between the surrounding temperature and the head presumed temperature, and temperature fall correction values upon suction.
  • a temperature fall upon suction can be corrected based on a difference from the surrounding temperature, and a head temperature after suction can be simultaneously predicted.
  • Difference Between Surrounding Temperature and Head Presumed Temperature (°C) ⁇ T in Suction (°C) 0 to 10 -1.2 10 to 20 -3.6 20 to 30 -6.0
  • the temperature of an ink tank In the case of an exchangeable head, the temperature of an ink tank must be presumed. Since the ink tank is in contact with the head, a temperature rise caused by ejection influences the ink tank. Thus, an ink tank temperature is presumed from an average of temperatures for last 10 minutes. In this manner, the ink tank temperature can be fed back to a temperature fall after a suction operation.
  • the temperature of a supplied ink is equal to the surrounding temperature, and the temperature of the ink tank need not be predicted.
  • a main tank 41 is arranged in an apparatus main body.
  • a sub-tank 43 is mounted on, e.g., a carriage.
  • a head chip 45 is covered by a cap 47.
  • a pump 49 applies a suction force to the cap 47.
  • the current head temperature is presumed from the print duty.
  • a pre-ejection condition is changed according to the head presumed temperature.
  • the ejection quantity When the head temperature is high, the ejection quantity is increased, and wasteful pre-ejection may be performed. In this case, control can be made to decrease the pre-ejection pulse width. Table 7 below shows the relationship between the head presumed temperature and the pulse width. Since the ejection quantity is increased as the temperature is higher, the ejection quantity is controlled by decreasing the pulse width.
  • Table 8 shows the relationship between the head presumed temperature, and the number of pulses in pre-ejection. Even at a normal temperature, the number of times of pre-ejection of nozzles at the end portion is set to be different from that of those at the central portion, thus suppressing the influence due to a temperature variation. As the head temperature becomes higher, since a temperature difference between the end portion and the central portion becomes larger, the difference in the number of times of pre-ejection is also increased. Thus, a variation in temperature distribution among nozzles can be suppressed, and efficient (least minimum) pre-ejection can be performed, thus allowing stable ejection. Head Presumed Temperature (°C) 1st to 16th Nozzles 17th to 48th Nozzles 49 to 64th Nozzles 20 to 30 10 8 10 30 to 40 10 7 10 40 to 50 10 6 10 Over 50 10 5 10
  • pre-ejection temperature tables may be used in units of ink colors.
  • Table 9 shows an example of a temperature table.
  • Bk black
  • M magenta
  • C cyan
  • the number of times of pre-ejection for Bk must be set to be larger than that for Y, M, and C.
  • the ejection quantity is increased as the temperature is higher, the number of times of pre-ejection is suppressed.
  • a method of presuming the head temperature while dividing nozzles 49 into two regions is also available.
  • counters 51 and 52 for independently obtaining print duties in units of nozzle regions are arranged, and the head temperature is presumed from the independently obtained print duty to independently set a pre-ejection condition.
  • a host computer 50 is connected to the counters 51 and 52.
  • the same reference numerals in Fig. 19B denote the same parts as in Fig. 5.
  • an average head temperature during a predetermined past period is presumed from a reference temperature sensor provided to a main body, and the print duty, and a predetermined restoration means is operated at intervals optimally set according to the average head temperature.
  • the restoration means controlled according to the average head temperature includes pre-ejection and wiping, which are performed at predetermined time intervals during printing (in a cap open state) so as to stabilize ejection.
  • the pre-ejection is performed for the purpose of preventing a non-ejection state or a change in density caused by evaporation of an ink from nozzle ports.
  • this embodiment sets an optimal pre-ejection interval and an optimal number of times of pre-ejection according to the average head temperature, so as to perform efficient pre-ejection from the viewpoints of time or ink consumption.
  • an average head temperature during a predetermined past period required in this embodiment can be easily obtained.
  • This embodiment pays attention to the fact that the ink evaporation quantity is associated with head temperatures at respective timings, and a total ink evaporation quantity during a predetermined period has a strong correlation with an average head temperature during that period.
  • a method of directly detecting the head temperature it is relatively easy to perform real-time control according to head temperatures at respective timings.
  • a special storage ⁇ arithmetic circuit is necessary for obtaining a past average head temperature necessary for the control of this embodiment.
  • the wiping as another ejection stabilization means to be controlled by this embodiment is performed for the purpose of removing an unnecessary liquid such as an ink or water vapor, or a solid foreign matter such as powder paper, dust or the like, attached on an orifice formation surface.
  • This embodiment pays attention to the fact that the wet quantity due to an ink varies depending on the head temperature, and evaporation of a wet component that makes it difficult to remove an ink or a foreign matter is associated with the head temperature (the temperature of the orifice formation surface).
  • an optimal wiping interval is set according to the past average head temperature, thus efficiently performing wiping.
  • the wet quantity or evaporation of the wet component associated with the wiping has a stronger correlation with the past average head temperature than with the head temperature at a time when the wiping is executed. Therefore, a head temperature presumption means of this embodiment is suitable.
  • Fig. 20 is a flow chart showing a schematic print sequence of an ink-jet recording apparatus of this embodiment.
  • a pre-ejection timer is set according to an average head temperature at that time, and is started.
  • a wiping timer is similarly set according to the average head temperature at that time, and is started. If no paper sheet is detected, a paper sheet is fed, and a carriage scan (print scan) operation is performed to print one line upon completion of a data input operation.
  • the paper sheet is discharged, and a stand-by state is set. If the print operation is continued, the paper sheet is fed by a predetermined amount, and it is then checked if its tail end is detected.
  • the wiping timer and the pre-ejection timer which are set according to the average head temperature, are checked and re-set. Wiping or pre-ejection is performed as needed, and the timers are started again. At this time, an average head temperature is calculated independently of the presence/absence of an operation, and the wiping timer and the pre-ejection timer are re-set according to the calculated average head temperature.
  • wiping and pre-ejection timings are finely re-set according to a change in average head temperature in units of print lines, so that optimal wiping and pre-ejection can be performed according to ink evaporation and wet situations.
  • the control waits for completion of the data input operation after the predetermined restoration operation, and the above-mentioned steps are repeated to perform the print scan operation again.
  • Table 10 below is a correspondence table of the pre-ejection interval, and the number of times of pre-ejection according to an average head temperature for the last 12 sec, and is also a correspondence table of the wiping interval according to an average head temperature for the last 48 sec.
  • the pre-ejection interval is shortened to decrease the number of times of pre-ejection.
  • the pre-ejection interval is prolonged to increase the number of times of pre-ejection.
  • Such a setting operation may be properly made in consideration of characteristics such as ejection characteristics according to evaporation•viscosity increase characteristics of an ink, and a change in density.
  • the pre-ejection interval may be prolonged at a high temperature.
  • Pre-ejection Wiping Interval (sec) Suction Interval (hours) Interval (sec) No. of Pulses 20 to 30 12 16 48 72 30 to 40 9 12 36 60 40 to 50 6 8 24 48 Over 50 3 4 12 3
  • a normal liquid ink tends to increase the wet quantity and difficulty of removal as the temperature becomes higher.
  • wiping is frequently performed at a high temperature.
  • This embodiment exemplifies a case of one recording head.
  • a restoration condition may be controlled according to an average head temperature in units of recording heads, or the plurality of heads may be simultaneously driven in correspondence with a recording head having the shortest interval.
  • This embodiment exemplifies a suction restoration means according to a presumed value of a past average head temperature for a relatively long period of time as another example of restoration control based on presumption of an average head temperature like in the fifth embodiment.
  • a recording head of an ink-jet recording apparatus is often arranged to attain a negative head at nozzle ports for the purpose of stabilizing a meniscus shape at the nozzle ports.
  • An unexpected bubble in an ink channel causes various problems in the ink-jet recording apparatuses, and particularly poses a problem in a system maintained at a negative head.
  • the suction restoration means is prepared for the purpose of removing such a bubble in the ink channel, and an ink whose viscosity is increased due to evaporation in the distal end portion of a nozzle port.
  • the ink evaporation quantity changes depending on the head temperature, as described above.
  • the growth of a bubble in the ink channel is further easily influenced by the head temperature, and a bubble tends to be formed as the temperature becomes higher.
  • a suction restoration interval is set according to the average head temperature for the last 12 hours, and suction restoration is performed more frequently as the average head temperature is higher.
  • the average temperature may be re-set for every page.
  • thermal coupling of the heads is realized by directly mounting the base portions, having high thermal conductivity, of the recording heads on a carriage, which is partially (including a common support portion of the heads) or entirely formed of a material having high thermal conductivity such as aluminum.
  • a restoration system is controlled according to the hysteresis of a temperature presumed from the temperature detected by a reference temperature sensor arranged in the main body, and the print duty.
  • a foreign matter such as an ink is often deposited on an orifice formation surface to shift the ejection direction or to cause an ejection error.
  • a wiping means is arranged.
  • a wiping member having a stronger scrubbing force may be prepared, or a wiping condition is temporarily changed to enhance a wiping effect.
  • the entrance amount (thrust amount) of a wiping member formed of a rubber blade into the orifice formation surface is increased to temporarily enhance a wiping effect (scrubbing mode).
  • the scrubbing mode is controlled according to the number of times of ejection weighted by the head temperature.
  • Table 11 shows weighting coefficients, which are multiplied with the number of times of ejection as base data of a print duty according to a head temperature presumed from the print duty. More specifically, at a higher temperature that easily causes a wet ink or non-wiped ink, the number of times of ejection serving as an index of deposition is increased in control.
  • the scrubbing mode When the weighted number of times of ejection reaches five millions, the scrubbing mode is operated.
  • the scrubbing mode is effective for removing a deposit.
  • the orifice formation surface may be mechanically damaged, and hence, execution of the scrubbing mode is preferably minimized.
  • control is made based on data directly correlated to deposition of a foreign matter like in this embodiment, an arrangement can be simple, and high reliability is assured.
  • the print mode may be controlled in units of ink colors having different deposition characteristics.
  • This embodiment also exemplifies a suction restoration means like in the sixth embodiment.
  • presumption of a bubble formed upon printing is performed in addition to presumption of a bubble due to a non-print state (non-print bubble), thus allowing accurate presumption of bubbles in an ink channel.
  • the ink evaporation quantity changes according to the head temperature.
  • the growth of a bubble in the ink channel is further easily influenced by the head temperature, and a bubble tends to grow more easily as the temperature is higher.
  • a non-print bubble can be presumed by counting a non-print time weighted by the head temperature.
  • a print bubble tends to be formed as the head temperature is higher, and of course, has a positive correlation with the number of times of ejection.
  • the print bubble can also be presumed by counting the number of times of ejection weighted by the head temperature.
  • Table 12 the number of points according to a non-print time (non-print bubble), and the number of points according to the number of times of ejection (print bubble) are set, and when a total of points reaches 100 millions, it is determined that bubbles in the ink channel may adversely influence ejection, and a suction restoration operation is performed to remove the bubbles.
  • the ejection quantity control described in the first and second embodiments may or may not be performed together.
  • steps associated with PWM control and sub-heater control can be omitted.
  • the ejection quantity can be controlled to be constant without arranging a temperature sensor in a recording head, and restoration processing can be properly performed. Therefore, a good recording image can be obtained independently of the precision of the temperature sensor.
  • a change in temperature of a head is detected from the past to the present time by calculation processing, thereby presuming a head temperature.
  • a surrounding temperature sensor for measuring the surrounding temperature is provided to a main body side, and a change in head temperature from the past to the present time, and also from the present time to the future is detected by calculation processing, so that optimal temperature control can be performed without arranging a head temperature sensor having a correlation with the head temperature.
  • a change in head temperature is predicted by evaluating it using a matrix calculated in advance within a range of a thermal time constant of the head and an applicable energy.
  • step S190 a sub-heater control table (Table 3) is referred to, thus obtaining an ON time (t) of the sub-heater before the print operation for the purpose of decreasing the difference ( ⁇ ).
  • This is a function of increasing the temperature of the entire head chip by the sub-heater when the presumed temperature of the head and the target temperature have a difference therebetween at the beginning of the print operation.
  • the temperature of the entire head chip can be controlled to be close to the target temperature as much as possible.
  • a heater ON operation in step S300 in the first embodiment is not performed in this embodiment.
  • the temperature prediction table (Fig. 14) is referred to, thus predicting a (future) head chip temperature immediately before printing when the sub-heater is assumed to be turned on for the setting time (S500).
  • a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the predicted head chip temperature ( ⁇ ) is calculated (S510). Needless to say, it is desirable that the temperatures ( ⁇ ) and ( ⁇ ) are equal to each other.
  • a PWM value at the start of the print operation is set according to the difference ( ⁇ ) with reference to the PWM value determination table (Table 4), so that an ejection quantity equal to that obtained in the print operation at the print target temperature ( ⁇ ) is obtained (S520, S530). It is difficult to cause the chip temperature to precisely approach the target temperature even using the sub-heater, and furthermore, it is very difficult to perform temperature correction in one line by the sub-heater. Thus, in this embodiment, the ejection quantity is corrected by the PWM method in accordance with the remaining difference from the target value. In particular, in this embodiment, the above-mentioned value P1 is increased to increase the ejection quantity.
  • the chip temperature of the head changes in accordance with its ejection duty during a one-line print operation. More specifically, since the difference ( ⁇ ) sometimes changes even in one line, it is desirable to optimize a PWM value in one line according to the change in difference. In this embodiment, 1.0 sec is required to print one line. Since the temperature prediction cycle of the head chip is 0.1 sec, one line is divided into 10 areas in this embodiment. The previously set PWM value at the beginning of the print operation corresponds to one at the beginning of the first area.
  • the PWM value at the beginning of the second area is set.
  • a power ratio of the first area is calculated based on the number of dots and the PWM value of the first area (S570).
  • a head chip temperature upon completion of the print operation of the first area is predicted by substituting the power ratio in (with reference to) the temperature prediction table (Fig. 14) (S580).
  • step S590 a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the head chip temperature ( ⁇ ) is calculated again.
  • a PWM value for printing the second area is obtained according to the difference ( ⁇ ) with reference to the PWM value determination table (Table 4), and the PWM value for the second area is set on a memory (S600, S610).
  • the power ratio in each subsequent area is calculated on the basis of the number of dots and the PWM value of the area, and a head chip temperature ( ⁇ ) upon completion of the print operation of the corresponding area is predicted. Then, a PWM value of the next area is set according to a difference between the print target value ( ⁇ ) and the predicted head chip temperature ( ⁇ ) (S550 to S610).
  • step S560 After the PWM values of all the 10 areas in one line are set, the flow advances from step S560 to step S620, and the heating operation of the sub-heater before printing is performed. Thereafter, a one-line print operation is performed according to the set PWM values (S630). When the one-line print operation is ended in step S630, the flow returns to step S120 to read the temperature of a reference thermistor, and the above-mentioned control is sequentially repeated.
  • the head chip temperature ( ⁇ ) gradually approaches the print target temperature ( ⁇ ). Even if a large temperature difference is present between the head chip temperature ( ⁇ ) and the print target temperature ( ⁇ ) like in an early period after power-ON, since PWM control is performed within one line, an actual ejection quantity can be controlled like that at the print target temperature, and high quality can be realized.
  • control operation of this embodiment is executed by a CPU 60 shown in Fig. 5.
  • the CPU 60 can obtain print duties of the respective areas with reference to line duty buffers 78c during temperature prediction control like in the first embodiment. Therefore, an arithmetic load on the CPU 60 can be reduced.
  • a difference between the surrounding temperature and the head temperature is calculated to check if the heating operation of the sub-heater immediately before printing is necessary.
  • Fig. 15B since the head temperature is not largely shifted from the target temperature, the heating operation of the sub-heater is not performed (Fig. 15D).
  • the head temperature (Fig. 15B) immediately before printing of an area A1 is predicted, and a PWM value (Fig. 15C) for the area A1 is set according to the difference. In this case, it is determined based on the PWM value of the area A1 that the area A1 is printed with a duty of 100%, and the temperature immediately before printing of the next area A2 is predicted.
  • the duty of the area A1 is high, it can be predicted that the temperature immediately before printing of the area A2 is high, and a low PWM value is set. Since the area A2 has a low duty (0%) and low PWM value, it can be predicted that the temperature immediately before printing of an area A3 is decreased. Therefore, a large PWM value immediately before printing of an area A4 is set.
  • the PWM value upon printing of each area is set based on the presence/absence of use and power of the sub-heater before printing, and the head temperature predicted value immediately before printing of each area, and thereafter, the print operations are performed. Since it can be predicted that the head temperature (Fig. 15B) will not be largely shifted from the reference temperature in the one-line print operation, the sub-heater is not turned on immediately before printing of the next line.
  • a difference between the surrounding temperature and the head temperature is calculated to check if the heating operation of the sub-heater immediately before printing is necessary.
  • the head temperature is largely shifted from the target temperature, it is predicted that the heating operation of the sub-heater is necessary, and the heating operation of the sub-heater is performed (Fig. 16D).
  • a head temperature upon completion of the heating operation of the sub-heater and immediately before printing of the area A1 (Fig. 16B) is predicted. Since it is predicted that the head temperature exceeds the target temperature, a minimum value is assigned to the PWM value (Fig. 16C) upon printing of the area A1.
  • the heating operation of the sub-heater can increase the temperature in an early period of the heating operation, since the difference between the head temperature and the target temperature is large, it can be easily predicted that the head temperature is decreased below the reference temperature upon completion of printing. Therefore, the head temperature immediately after the sub-heater is turned on is intentionally set to exceed the target temperature.
  • the minimum value is assigned to the PWM value of the area A1.
  • the duty (100%) of the area A1 is high, it is predicted that the temperature immediately before printing of an area A2 is not decreased below the target temperature, and a minimum PWM value is set for the area A2.
  • the head temperature is gradually decreased to a temperature below the target temperature, and optimal PWM values are set. Thereafter, the heating operation of the sub-heater and the actual print operations are performed, while setting the PWM values of the areas in the same manner as in Figs. 15A to 15E.
  • a difference between the cases in Figs. 15A to 15E and Figs. 16A to 16E is that the ejection quantity does not exceed the ejection quantity (Fig. 15E) at the target temperature in the former case, while the ejection quantity sometimes exceeds the ejection quantity (Fig. 16E) at the target temperature in the latter case.
  • a negative PWM value may be provided.
  • a future head temperature can be predicted without using a temperature sensor
  • various head control operations can be performed before an actual print operation, and a more proper recording operation can be attained. Since it is possible to predict a temperature with reference to one temperature prediction table, prediction control can be facilitated.
  • the temperature prediction described in the ninth embodiment can be applied to each of the third to eighth embodiments described previously.
  • the head temperature is not limited to a presumed temperature at the present time, and a future head temperature can also be easily predicted. Therefore, the optimal pre-ejection interval and the optimal number of times of pre-ejection may be set in consideration of a future ejection condition. In addition, optimal suction restoration control may set. Furthermore, the "weighted number of times of ejection" taking a future ejection condition into consideration may be used in a calculation of the "weighted number of times of ejection" to set optimal control.
  • ink evaporation characteristics or “growth of bubbles in an ink channel” taking a future ejection condition into consideration may be used in presumption or prediction of the "ink evaporation characteristics” or “growth of bubbles in an ink channel” to set optimal control.
  • a temperature sensor is provided to a recording head, and a predicted (calculated) head temperature is corrected to improve prediction precision.
  • a head 8b has a temperature sensor 8e, and a head temperature detected by the temperature sensor 8e can be detected by a CPU 60.
  • Fig. 25 shows a heater board of a recording head, which can be used in this embodiment.
  • a temperature sensor, a temperature control heater, an ejection heater, and the like are arranged on the heater board.
  • Fig. 25 is a schematic plan view of the heater board.
  • the temperature sensors 8e are arranged at both the right and left sides of an array of a plurality of ejection heaters 8c on an Si substrate 853. These ejection heaters 8c and the temperature sensors 8e are pattern-arranged together with temperature control heaters 8d similarly arranged at both the right and left sides of the heater board, and are simultaneously formed in a semiconductor process.
  • the temperature detected by the temperature sensor 8e an average value of temperatures detected by the two temperature sensors 8e is used as the temperature detected by the temperature sensor 8e.
  • the temperature detected by a temperature sensor (to be referred to as a reference thermistor hereinafter), on a main body printed circuit board (to be referred to as a PCB hereinafter), for detecting the surrounding temperature is read (S120), thus detecting the surrounding temperature.
  • a time elapsed from the ON operation of the power supply is read from the temperature correction timer (S130), and a precise surrounding temperature from which the influence of heat generating members is corrected is obtained with reference to a temperature correction table (Table 1) (S140).
  • a current head chip temperature ( ⁇ ) is predicted with reference to a temperature prediction table (Fig. 14), and the control waits for input of a print signal.
  • a matrix value 0 thermal equilibrium
  • the sum is multiplied with 1. If no print signal is input, the flow returns to step S120 to read the temperature of the reference thermistor again.
  • the head chip temperature prediction cycle is set to be 0.1 sec.
  • the temperature prediction table shown in Fig. 14 is a matrix table showing temperature rise characteristics per unit time, determined by the thermal time constant of the head and an energy applied to the head, as described above. Strictly speaking, since the thermal time constant of the head varies depending on heads, the temperature rise characteristics may slightly vary.
  • the correction value "CAL" for the temperature prediction table is a coefficient for correcting this variation.
  • step S162 a paper feed/discharge operation of a recording medium is performed. If YES in step S162, the flow branches to a temperature prediction table correction routine (S164).
  • the reason why the temperature of the head temperature sensor is read during a paper feed/discharge period is that a change in temperature is steady since the head is not driven (heated), and the influence of a delay of heat conduction is small.
  • step S170 a print target temperature ( ⁇ ) of the head chip, at which an optimal driving operation can be performed at the current surrounding temperature, is obtained with reference to a target (driving) temperature table (Table 2).
  • step S190 an ON time (t) of a sub-heater before printing for the purpose of decreasing the difference ( ⁇ ) is obtained with reference to a sub-heater control table (Table 3).
  • the temperature prediction table (Fig. 14) is referred to, thereby predicting a (future) head chip temperature immediately before the beginning of printing under an assumption that the sub-heater is turned on for the setting time (S500).
  • the predicted temperature is corrected by the correction value CAL (S505), thereby setting the head chip temperature.
  • a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the predicted head chip temperature ( ⁇ ) is calculated (S510). Needless to say, it is desirable that the temperatures ( ⁇ ) and ( ⁇ ) are equal to each other.
  • a PWM value at the start of the print operation is set according to the difference ( ⁇ ) with reference to a PWM value determination table (Table 4), so that an ejection quantity equal to that obtained in the print operation at the print target temperature ( ⁇ ) is obtained (S520, S530).
  • the chip temperature of the head changes due to its ejection duty during a one-line print operation. More specifically, since the difference ( ⁇ ) sometimes changes even in one line, it is desirable to optimize a PWM value in one line according to the change in difference. In this embodiment, 1.0 sec is required to print one line. Since the temperature prediction cycle of the head chip is 0.1 sec, one line is divided into 10 areas in this embodiment. The previously set PWM value at the beginning of the print operation corresponds to one at the beginning of the first area.
  • the PWM value at the beginning of the second area is set.
  • a power ratio of the first area is calculated based on the number of dots and the PWM value of the first area (S570).
  • a head chip temperature upon completion of the print operation of the first area is predicted by substituting the power ratio in (with reference to) the temperature prediction table. (Fig. 14) (S580).
  • the predicted temperature is corrected by the correction value CAL (S585), thus setting the head chip temperature ⁇ .
  • step S590 a difference ( ⁇ ) between the print target temperature ( ⁇ ) and the head chip temperature ( ⁇ ) is calculated again.
  • a PWM value for printing the second area is obtained according to the difference ( ⁇ ) with reference to the PWM value determination table (Table 4), and the PWM value for the second area is set on a memory (S600, S610).
  • the power ratio in the corresponding area is calculated on the basis of the number of dots and the PWM value of the immediately preceding area, and a head chip temperature ( ⁇ ) upon completion of the print operation of the corresponding area is predicted.
  • the predicted temperature is corrected by the correction value CAL.
  • a PWM value of the next area is set according to the difference between the print target value ( ⁇ ) and the predicted head chip temperature ( ⁇ ) (S550 to S610).
  • the flow advances from step S560 to step S620, and the heating operation of the sub-heater before printing is performed.
  • a one-line print operation is performed according to the set PWM values (S630).
  • the flow returns to step S120 to read the temperature of a reference thermistor, and the above-mentioned control is sequentially repeated.
  • the head chip temperature ( ⁇ ) gradually approaches the print target temperature ( ⁇ ). Even if a large temperature difference is present between the head chip temperature ( ⁇ ) and the print target temperature ( ⁇ ) like in an early period after power-ON, since PWM control is performed within one line, an actual ejection quantity can be controlled like that at the print target temperature, and high quality can be realized. Furthermore, since a predicted temperature is corrected by the correction value CAL indicating an error between a measured temperature and a predicted temperature in a steady state of the head temperature (S155, S505, S585), the head temperature can be more accurately predicted.
  • the correction value CAL of the temperature prediction table is updated during only the paper feed/discharge operation of a recording medium. This is because, in addition to the steady state of the head temperature described above, since the paper feed/discharge operation of a recording medium requires a time of several seconds, the correction value CAL can be updated without influencing a recording time as long as control can be made within this time. More specifically, the temperature of the head chip is measured several times, thus preventing a detection error due to noise. In this embodiment, correction is performed once per paper feed/discharge operation. Alternatively, correction (prediction ⁇ measurement ⁇ correction) may be repeated a plurality of number of times during a single paper feed/discharge operation, thus improving the precision of the correction value CAL.
  • a method of repeating correction until the correction value CAL is converged to a predetermined value may be employed.
  • the correction timing is not limited to that during a paper feed/discharge operation, but may be set before or during a print operation of each line.
  • the correction value CAL disappears when the power supply is turned off.
  • the correction value may be stored in, e.g., a programmable nonvolatile storage medium (e.g., an EEPROM).
  • the temperature prediction table itself may be allocated on a nonvolatile storage medium, and may be rewritten in every correction.
  • the correction value may be calculated by other calculation means.
  • the recording apparatus comprises a head temperature measurement means for measuring the temperature of a recording head, a surrounding temperature measurement means for measuring the surrounding temperature, a temperature calculation means for calculating a variation in temperature of the recording head, and a control means for controlling the recording head on the basis of the calculation result. Therefore, the following advantages can be provided:
  • the temperature prediction described in the tenth embodiment can be applied to each of the third to eighth embodiments described previously like in the ninth embodiment.
  • a temperature sensor is provided to a recording head, and a head temperature is predicted with reference to the temperature detected by the temperature sensor in consideration of a predicted variation in temperature.
  • the arrangement of this embodiment is the same as that shown in Figs. 24 and 25 described in the tenth embodiment.
  • a future temperature can be predicted from a predicted print ratio, thus preventing a trouble caused by a time delay in temperature detection. Since response time characteristics in temperature control can be improved, ink ejection can be stabilized.
  • the temperature prediction described in the eleventh embodiment can be applied to each of the third to eighth embodiments described previously like in the ninth embodiment.
  • control can be performed in correspondence with a predicted head temperature, and response characteristics can be further improved as compared to control that is performed while predicting a head temperature.
  • This embodiment can also be applied to a case wherein a sub-heater is controlled based on the print ratio.
  • a future temperature predicted from the current head temperature and a future print ratio is lower than an ink ejection standard temperature (23°C)
  • the ON time of the sub-heater is controlled according to the difference between the two temperatures so as to always obtain a constant head temperature, thus stabilizing ejection.
  • a time shown in Table 3 is used as the ON time of the sub-heater according to the difference between the predicted future temperature and the ink ejection standard temperature. Since the ON time of the sub-heater is controlled beforehand, a control time delay at that time can be avoided, and control having good response characteristics can be realized.
  • the energization time is used as an index of an energy to be applied to head.
  • the present invention is not limited to this.
  • the number of print dots may be simply used.
  • a print time and a non-print time may be used.
  • the present invention brings about excellent effects particularly in a recording head and a recording device of the ink jet system using a thermal energy among the ink jet recording systems.
  • the above system is applicable to either one of the so-called on-demand type and the continuous type.
  • the case of the on-demand type is effective because, by applying at least one driving signal which gives rapid temperature elevation exceeding nucleus boiling corresponding to the recording information on electrothermal converting elements arranged in a range corresponding to the sheet or liquid channels holding liquid (ink), a heat energy is generated by the electrothermal converting elements to effect film boiling on the heat acting surface of the recording head, and consequently the bubbles within the liquid (ink) can be formed in correspondence to the driving signals one by one.
  • the present invention can be also effectively constructed as disclosed in JP-A-59-123670 which discloses the construction using a slit common to a plurality of electrothermal converting elements as a discharging portion of the electrothermal converting element or JP-A-59-138461 which discloses the construction having the opening for absorbing a pressure wave of a heat energy corresponding to the discharging portion.
  • a recording head of the full line type having a length corresponding to the maximum width of a recording medium which can be recorded by the recording device
  • either the construction which satisfies its length by a combination of a plurality of recording heads as disclosed in the above specifications or the construction as a single recording head which has integratedly been formed can be used.
  • the present invention can exhibit the effects as described above more effectively.
  • the invention is effective for a recording head of the freely exchangeable chip type which enables electrical connection to the main device or supply of ink from the main device by being mounted onto the main device, or for the case by use of a recording head of the cartridge type provided integratedly on the recording head itself.
  • a restoration means for the recording head, preliminary auxiliary means, and the like provided as a construction of the recording device of the invention because the effect of the invention can be further stabilized.
  • Specific examples of them may include, for the recording head, capping means, cleaning means, pressurization or aspiration means, and electrothermal converting elements or another heating element or preliminary heating means according to a combination of them. It is also effective for performing a stable recording to realize the preliminary mode which executes the discharging separately from the recording.
  • the invention is extremely effective for not only the recording mode of only a primary color such as black or the like but also a device having at least one of a plurality of different colors or a full color by color mixing, depending on whether the recording head may be either integratedly constructed or combined in plural number.

Claims (16)

  1. Aufzeichnungsgerät, mit:
    einem Aufzeichnungskopf (5012) zum Ausstoß von Tinte aus einer Ausstoßstelle (27) unter Verwendung von Blasen, die in der Tinte durch Wärmeenergie durch Anlegen eines Ansteuersignals an ein elektro-thermisches Wandlerglied entstehen;
    einem Ansteuermittel zum Anliefern des Ansteuersignals;
    einem Steuermittel (CPU60) zum Steuern der Menge (Vd) an aus der Ausstoßstelle durch Wechseln des Ansteuersignals ausgestoßen Tinte;
    einem Temperaturmeßmittel (5024) zum Messen der Umgebungstemperatur; und
    einem Rechenmittel (CPU60) zum Errechnen von Temperaturänderungen des Aufzeichnungskopfes;
    dadurch gekennzeichnet, daß
       die Rechenmittel eingerichtet sind zum Errechnen einer Temperaturänderung des Aufzeichnungskopfes gemäß der thermischen Zeitkonstanten des Aufzeichnungskopfes und gemäß der an den Aufzeichnungskopf während einer vorbestimmten Zeiteinheit gelieferten Energie, und des weiteren mit:
       einem Mittel (CPU60) zum Vorhersagen oder Schätzen der Temperatur des Aufzeichnungskopfes gemäß der vom Rechenmittel errechneten Temperaturänderung und der vom Meßmittel gemessenen Umgebungstemperatur, wobei das Steuermittel eingerichtet ist zur Änderung des Ansteuersignals für den Aufzeichnungskopf aufgrund der vorhergesagten oder geschätzten Temperatur, um so die Tintenausstoßmenge zu steuern, wobei das Rechenmittel eine Variation der Temperatur auf der Grundlage des vom Steuermittel geänderten Ansteuersignals errechnet.
  2. Gerät nach Anspruch 1, dessen Steuersignal einen Vorheizimpuls (P1) umfaßt, der vom Hauptheizimpuls (P3) durch ein Intervall (P2) getrennt ist.
  3. Gerät nach Anspruch 2, dessen Steuermittel die Impulsbreite des Vorheizimpulses auf der Grundlage der vorhergesagten oder geschätzten Temperatur ändert.
  4. Gerät nach einem der vorstehenden Ansprüche, mit:
    einem Kopftemperatur-Meßmittel zum Messen der Temperatur des Aufzeichnungskopfes;
    einem Feststellmittel zum Feststellen der Differenz zwischen der vorhergesagten Temperatur und der vom Kopftemperatur-Meßmittel gemessenen Temperatur; und mit
    einem Korrekturmittel (CPU60) zum Korrigieren der Rechnungen des Rechenmittels gemäß der Differenz.
  5. Gerät nach einem der vorstehenden Ansprüche, bei dem das Auswählen von zu errechnenden Temperaturänderungen des Aufzeichnungskopfes im Betrieb aus einer Tabelle der Temperaturänderungen erfolgt.
  6. Gerät nach einem der vorstehenden Ansprüche, bei dem das Rechenmittel über eine Matrixtabelle verfügt, die Temperaturänderungen pro Zeiteinheit anzeigt, bestimmt gemäß der thermischen Konstante des Aufzeichnungskopfes und dem Pegel des während der Zeiteinheit an den Aufzeichnungskopf gelieferten Ansteuerungssignals.
  7. Gerät nach einem der vorstehenden Ansprüche, bei dem das Steuermittel eingerichtet ist, einen Vorausstoß des Aufzeichnungskopfes gemäß der vorhergesagten oder geschätzten Temperatur zu veranlassen.
  8. Gerät nach einem der vorstehenden Ansprüche, bei dem das Steuermittel eingerichtet ist, eine Saugwiederherstellung des Aufzeichnungskopfes gemäß der vorhergesagten oder geschätzten Temperatur zu veranlassen.
  9. Gerät nach einem der vorstehenden Ansprüche, bei dem das Steuermittel eingerichtet ist, die Temperatursteuerung des Aufzeichnungskopfes gemäß der vorhergesagten oder geschätzten Temperatur zu veranlassen.
  10. Gerät nach einem der vorstehenden Ansprüche, in Kombination mit einer der nachstehenden Einrichtungen: Faksimileeinrichtung, Kopierer oder Endeinrichtung für einen Computer.
  11. Aufzeichnungsverfahren, mit den Verfahrensschritten:
    Ausstoßen von Tinte aus einer Ausstoßstelle (27) in einem Aufzeichnungskopf (5012) unter Verwendung von in der Tinte durch Wärmeenergie erzeugter Blasen durch Anlegen eines Ansteuersignals an ein elektro-thermisches Wandlerglied;
    Messen (5024) der Umgebungstemperatur; und
    Errechnen (CPU60) von Temperaturänderungen des Aufzeichnungskopfes; gekennzeichnet durch die Verfahrensschritte:
    Errechnen einer Temperaturänderung des Aufzeichnungskopfes gemäß der thermischen Zeitkonstante des Aufzeichnungskopfes und der während einer vorbestimmten Zeiteinheit an den Aufzeichnungskopf gelieferten Energie, und
    Vorhersagen oder Schätzen der Temperatur des Aufzeichnungskopfes gemäß der im Verfahrensschritt des Errechnens errechneten Temperaturänderung und Anwenden eines Steuermittels zum Ändern des Ansteuersignals für den Aufzeichnungskopf auf der Grundlage der vorhergesagten oder geschätzten Temperatur, um so die Menge des Tintenausstoßes zu steuern, und Errechnen einer Temperaturänderung des Aufzeichnungskopfes auf der Grundlage des vom Steuermittel geänderten Ansteuersignals.
  12. Verfahren nach Anspruch 11, bei dem das Ansteuersignal einen Vorheizimpuls (P1) umfaßt, der vom Hauptheizimpuls (P3) um ein Intervall (P2) getrennt ist.
  13. Verfahren nach Anspruch 12, bei dem die Impulsbreite des Vorheizimpulses eine Änderung auf der Grundlage der vorhergesagten Temperatur erfährt.
  14. Verfahren nach einem der Ansprüche 11 bis 13, mit dem weiteren Verfahrensschritt des Messens der Temperatur vom Aufzeichnungskopf, Feststellen der Differenz zwischen der vorhergesagten und der gemessenen Temperatur, und Korrigieren der Rechnungen der vorhergesagten Temperatur gemäß der Differenz.
  15. Verfahren nach einem der Ansprüche 11 bis 14, bei dem die Auswahl zu errechnender Temperaturänderungen aus einer Temperaturvariationstabelle erfolgt.
  16. Verfahren nach einem der Ansprüche 11 bis 15, bei dem das Errechnen der vorhergesagten Temperatur anhand einer Matrixtabelle erfolgt, die Temperaturänderungen pro Zeiteinheit aufzeigt, bestimmt gemäß der thermischen Zeitkonstante des Wiedergabekopfes und Pegeln des an den Aufzeichnungskopf während der Zeiteinheit gelieferten Ansteuersignals.
EP92302313A 1991-03-20 1992-03-18 Temperatursteuerung für thermischen Tintenstrahlaufzeichnungskopf Expired - Lifetime EP0505154B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP00200209A EP0997287B1 (de) 1991-03-20 1992-03-18 Temperatursteuerung für Tintenstrahlaufzeichnungskopf unter Verwendung von Wärmeenergie

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JP57460/91 1991-03-20
JP5746091 1991-03-20
JP5745791 1991-03-20
JP5746091 1991-03-20
JP57457/91 1991-03-20
JP5745791 1991-03-20
JP44773/92 1992-03-02
JP4044773A JP2974487B2 (ja) 1991-03-20 1992-03-02 記録装置
JP4477392 1992-03-02

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WO2004048100A1 (en) * 2002-11-23 2004-06-10 Silverbrook Research Pty Ltd Self-cooling thermal ink jet printhead
CN100386207C (zh) * 2002-11-23 2008-05-07 西尔弗布鲁克研究有限公司 自冷却热喷墨打印头
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EP0505154A2 (de) 1992-09-23
DE69233516D1 (de) 2005-07-07
DE69233516T2 (de) 2006-05-04
EP0505154A3 (en) 1993-03-24
DE69232385D1 (de) 2002-03-14

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