EP0493039A2 - Wärme-Tintenstrahldruckkopf mit gesteigerter Tropfengeschwindigkeit - Google Patents

Wärme-Tintenstrahldruckkopf mit gesteigerter Tropfengeschwindigkeit Download PDF

Info

Publication number
EP0493039A2
EP0493039A2 EP91311898A EP91311898A EP0493039A2 EP 0493039 A2 EP0493039 A2 EP 0493039A2 EP 91311898 A EP91311898 A EP 91311898A EP 91311898 A EP91311898 A EP 91311898A EP 0493039 A2 EP0493039 A2 EP 0493039A2
Authority
EP
European Patent Office
Prior art keywords
ink
channel
printhead
ink jet
jet printhead
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.)
Withdrawn
Application number
EP91311898A
Other languages
English (en)
French (fr)
Other versions
EP0493039A3 (en
Inventor
Peter A. Torpey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Publication of EP0493039A2 publication Critical patent/EP0493039A2/de
Publication of EP0493039A3 publication Critical patent/EP0493039A3/en
Withdrawn legal-status Critical Current

Links

Images

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
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14032—Structure of the pressure chamber
    • B41J2/1404—Geometrical characteristics
    • 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
    • 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
    • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
    • B41J2202/01—Embodiments of or processes related to ink-jet heads
    • B41J2202/11—Embodiments of or processes related to ink-jet heads characterised by specific geometrical characteristics

Definitions

  • the invention relates generally to thermal ink jet printing systems, and more particularly to an improved thermal ink jet printhead having an increased drop velocity.
  • a printhead uses thermal energy to produce a vapor bubble in an ink-filled channel in order to expel a droplet of ink.
  • This type of printing is known as thermal ink jet printing.
  • thermal ink jet printing As disclosed in U.S. Patent No. 4,663,359 to Ayata et al., such printing systems generally include one or more ink-filled channels. One end of each channel is in fluidic communication with a relatively small ink reservoir. The opposite end of each channel, referred to as the nozzle, is an opening through which the ink can be expelled onto a recording medium such as paper.
  • a thermal energy generator usually a resistor, is located in each of the channels at a predetermined distance from the nozzle.
  • the resistors are individually addressed with a current pulse to momentarily vaporize the ink and form a bubble that will expel an ink droplet.
  • the ink bulges from the nozzle, where it is restrained by surface tension.
  • the bubble begins to contrary the ink remaining in the channel continues to move toward the collapsing bubble, causing a volumetric contraction of the ink at the nozzle. This contraction results in the separation of the bulging ink from the nozzle, thus producing a droplet.
  • the velocity and momentum of the droplet which is provided by the acceleration of the bubble as it grows inside the channel, is substantially along a straight line directed toward the recording medium.
  • the heating element is placed closer to the nozzle so that only a relatively small quantity of ink needs to be acted upon as the bubble grows and expands. Consequently, the bubble imparts a greater momentum to this small quantity of ink than it would if the heating element were placed farther from the nozzle.
  • the duration of the current pulse provided to the heating element is increased to generate more thermal energy. This thermal energy increases the quantity of heat present in the ink prior to the nucleation of the micro- sized vapor bubbles, yielding a more rapid or explosive bubble growth.
  • Blowout or ingestion occurs when a growing bubble within a channel expands so greatly that it communicates closely with outside air such that the boundary between bubble and outside air may be broken, allowing ingestion of outside air into the low pressure bubble. Because of this result, ingested air may be trapped in the channel. This air bubble can seriously degrade the nucleation or ejection process of the ink as it forms a bubble, producing a misdirected, weakly propelled droplet. Since placement of the heating element closer to nozzle and an increase in the duration of the heating pulse both produce a greater rate of bubble growth, the likelihood of blowout is also increased.
  • US-A-4,638,337 which is assigned to the same assignee as the present invention and which is incorporated herein by reference, reduces the problem of blowout while maintaining an increased bubble velocity.
  • the heating elements generating the bubbles are positioned in a recess located in the lower surface of the channel.
  • the walls of the recess are perpendicular to the lateral flow of ink in the channel. These walls constrain the expanding bubble from growing in the lateral direction and force the bubble to grow in a direction perpendicular to the direction of ink flow.
  • This arrangement reduces the likelihood of blowout, because the bubble does not expand as rapidly toward the nozzle. Therefore, the heating element may be placed closer to the nozzle and the duration of the pulses to the heating element may be increased without overly increasing the likelihood of blowout.
  • the present invention relates to a thermal ink jet printhead for ejecting and propelling ink droplets on demand that overcomes the deficiencies noted above.
  • the present invention provides a thermal ink jet printhead, including at least one elongated channel that forms a straight ink flow path therethrough.
  • the channel has an orifice at one end for ejecting the ink and an inlet at the other end for communicating with an ink reservoir.
  • a heating element is disposed inside the channel and it has a surface that contacts the ink.
  • a constrictor is placed in the channel near the orifice so that the velocity of the ink flow through the orifice is increased.
  • the volume flow rate of the ink is increased, thereby increasing the velocity of the droplet expelled from the nozzle.
  • This increase in velocity is advantageously accomplished without supplying additional heat to the ink and without moving the heating element closer to the nozzle. As a result, droplet velocity is increased without increasing the probability that blowout will occur.
  • an additional constrictor is disposed inside the channel near the inlet thereof. This constrictor aids in balancing the inertial forces against which the bubble expands.
  • a typical carriage type, multicolor, thermal ink jet printing device 10 is shown in Figure 1.
  • a linear array of ink droplet producing channels is housed in each printhead 11 of each ink supply cartridge 12 which may optionally be disposable.
  • One or more ink supply cartridges 12 are replaceably mounted on a reciprocating carriage assembly 14 which reciprocates back and forth in the direction of arrow 13 on guide rails 15.
  • the channels terminate with orifices or nozzles aligned perpendicular to the carriage reciprocating direction and parallel to the stepping direction 17 of a recording medium 16, such as paper.
  • the printhead prints a swath of information on the stationary recording medium as it moves in one direction.
  • the recording medium Prior to the carriage and printhead reversing direction, the recording medium is stepped by the printing device a distance equal to the printed swath in the direction of arrow 17 and then the printhead moves in the opposite direction printing another swath of information.
  • Droplets 18 are expelled and propelled to the recording medium from the nozzles in response to digital data signals received by the printing device controller (not shown), which in turn selectively addresses with a current pulse the individual heating elements located in the printhead channels a predetermined distance from the nozzles.
  • the current pulses passing through the printhead heating elements vaporize the ink contacting the heating elements and produce temporary vapor bubbles to expel droplets of ink from the nozzles.
  • Figure 2 shows a cross-sectional view along the length of a known channel in a thermal ink jet printhead.
  • a reservoir (not shown in this Figure) continuously supplies the ink 60 to the back section (i.e. the left-hand side in Figure 2) of the channel by capillary action.
  • the ink 60 located at the nozzle 27 forms a meniscus, the surface tension of which prevents the ink 60 from escaping therefrom.
  • Figure 2 shows the channel at a time when a heating element 34 in a recess 64 has been addressed with a current pulse to vaporize the ink 60 contacting the surface of the heating element 34 to form a bubble 61.
  • the bubble 61 causes the ink to bulge from the nozzle 27, producing a droplet 18 that is seen in Figure 2 just prior to its breaking away as a discrete droplet.
  • the recessed walls 62 of the insulative layer 58 restrict the lateral spread of the vapor bubble 61, forcing the bubble 61 to grow in a direction perpendicular to the surface of the heating element 34. As a result, the blowout phenomenon is reduced.
  • Figure 3 shows a cross-sectional view across the length of the channel of the present invention. Like reference numerals are used for the components in Figure 3 that correspond to those in Figure 2.
  • V2 V1x(A1/A2)
  • Equation 2 indicates that as the area A2 decreases relative to A1, the velocity of the ink 60 at the exit of the nozzle 27 increases. Although this equation is only approximately accurate because V1 is not completely independent of the channel geometry, it does accurately point out the general trends.
  • the bubble 61 would tend to exert an even greater fraction of its force back toward the reservoir, decreasing the force on the droplet 18 and hence decreasing the maximum velocity of the droplet 18. For this reason, it is advantageous to balance the forces exerted by the bubble 61 by equally constricting the front and back sections of the channel.
  • the channel may be formed by any of the various techniques known in the art.
  • U.S. Patent No. 4,638,337 which has been incorporated herein by reference, produces the upper substrate 31 and the lower substrate 28 from polished silicon wafers. Grooves are formed in the upper substrate 31 to form the channels.
  • a number of protective and insulating layers may be formed on the lower substrate 28 before it is joined with the upper substrate 31.
  • a thick film insulative layer 58 formed from a polyimide material may be deposited on the lower substrate 28. The layer 58 can be etched away at a particular location to form the recess 64 containing the heating element 34.
  • the surface of the upper substrate 31 is bonded to the lower substrate 28 so that the heating element 34 is positioned in the channel.
  • the front and back sections of the channel may be constricted in various ways that depend on the fabrication process used to form the channel. Any fabrication process known in the art may be used. For example, one simple method of producing the constriction is to etch the upper substrate 31 so that the mid- section of the channel is wider than the front and back sections. This etching process produces the upper-front constrictor 71 and upper-back constrictor 75 seen in Figure 3. A further constriction can be achieved by depositing an additional insulative layer 58 on what will become the front and back sections of the channel to form the lower-front and lower-back constrictors 73 and 77.
  • the mid-section of the channel is etched to a width of about 70 microns (and thus about 49 microns in height) and the front and back sections are etched to a width of about 60 microns (and thus about 42 microns in height).

Landscapes

  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
EP19910311898 1990-12-20 1991-12-20 Thermal ink jet printhead having an increased drop velocity Withdrawn EP0493039A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US63115290A 1990-12-20 1990-12-20
US631152 1996-04-15

Publications (2)

Publication Number Publication Date
EP0493039A2 true EP0493039A2 (de) 1992-07-01
EP0493039A3 EP0493039A3 (en) 1993-02-24

Family

ID=24530000

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910311898 Withdrawn EP0493039A3 (en) 1990-12-20 1991-12-20 Thermal ink jet printhead having an increased drop velocity

Country Status (2)

Country Link
EP (1) EP0493039A3 (de)
JP (1) JPH071729A (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3659303B2 (ja) 1997-12-11 2005-06-15 富士ゼロックス株式会社 液体噴射記録装置の製造方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4638337A (en) * 1985-08-02 1987-01-20 Xerox Corporation Thermal ink jet printhead
US4723136A (en) * 1984-11-05 1988-02-02 Canon Kabushiki Kaisha Print-on-demand type liquid jet printing head having main and subsidiary liquid paths
US4897674A (en) * 1985-12-27 1990-01-30 Canon Kabushiki Kaisha Liquid jet recording head
EP0461940A2 (de) * 1990-06-15 1991-12-18 Canon Kabushiki Kaisha Tintenstrahlaufzeichnungsgerät- und steuerungsverfahren

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4723136A (en) * 1984-11-05 1988-02-02 Canon Kabushiki Kaisha Print-on-demand type liquid jet printing head having main and subsidiary liquid paths
US4638337A (en) * 1985-08-02 1987-01-20 Xerox Corporation Thermal ink jet printhead
US4897674A (en) * 1985-12-27 1990-01-30 Canon Kabushiki Kaisha Liquid jet recording head
EP0461940A2 (de) * 1990-06-15 1991-12-18 Canon Kabushiki Kaisha Tintenstrahlaufzeichnungsgerät- und steuerungsverfahren

Also Published As

Publication number Publication date
JPH071729A (ja) 1995-01-06
EP0493039A3 (en) 1993-02-24

Similar Documents

Publication Publication Date Title
KR100554807B1 (ko) 유체액적을분사하기위한프린트헤드및유체액적형성방법
JP2653652B2 (ja) サーマルインクジエツトプリンターに用いるためのインクジエツトプリントヘツド
US5897789A (en) Valve assembly for controlling fluid flow within an ink-jet pen
US7506962B2 (en) Liquid discharge method, liquid discharge head and liquid discharge apparatus
US4897674A (en) Liquid jet recording head
EP0100624A1 (de) Tintenstrahldrucker mit einer mittels Dampfblase angetriebenen flexiblen Membran
EP0513441A1 (de) Druckkopf ohne Düsen für Tintenstrahldrucker
JPH0251734B2 (de)
JPS6233648A (ja) 熱式インキジエツトプリントヘツド
US6805432B1 (en) Fluid ejecting device with fluid feed slot
US4549191A (en) Multi-nozzle ink-jet print head of drop-on-demand type
CA2134385C (en) Method and apparatus for elimination of misdirected satellite drops in thermal ink jet printhead
KR970004203B1 (ko) 잉크 제트 기록 장치
US6109744A (en) Asymmetric restrictor for ink jet printhead
EP0493039A2 (de) Wärme-Tintenstrahldruckkopf mit gesteigerter Tropfengeschwindigkeit
EP2170614B1 (de) Fluidausstossvorrichtung
US6390607B2 (en) Ink jet print head
EP0067948B1 (de) Methode und Apparat zum Produzieren von Flüssigkeitstropfen auf Befehl
JPH07195697A (ja) インクジェット記録ヘッド，インクジェット記録方法およびインクジェット記録装置
JP3959837B2 (ja) インクジェットヘッド
GB2334000A (en) Method of fabricating a bimetallic cantilever valve assembly for controlling ink flow within an inkjet printhead
EP0376922B1 (de) Tintenstrahldrucker
JPH03295657A (ja) インクジェットプリンタヘッド
JP3093322B2 (ja) インクジェット記録ヘッド及び該記録ヘッドを用いたインクジェット記録装置
JPH0343254A (ja) 熱インクジェットの印字ヘッド

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19930803

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19940618