EP0792745A2 - Tête d'enregistrement à jet d'encre - Google Patents
Tête d'enregistrement à jet d'encre Download PDFInfo
- Publication number
- EP0792745A2 EP0792745A2 EP19970301275 EP97301275A EP0792745A2 EP 0792745 A2 EP0792745 A2 EP 0792745A2 EP 19970301275 EP19970301275 EP 19970301275 EP 97301275 A EP97301275 A EP 97301275A EP 0792745 A2 EP0792745 A2 EP 0792745A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- heating surface
- channel
- ejector
- heating element
- terminal
- 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- Withdrawn
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
- B41J2/015—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
- B41J2/04565—Control methods or devices therefor, e.g. driver circuits, control circuits detecting heater resistance
-
- 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
- B41J2/0459—Height 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
- B41J2/04591—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
- B41J2/04593—Dot-size modulation by changing the size of the drop
-
- 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
- B41J2/14088—Structure of heating means
- B41J2/14112—Resistive element
- B41J2/1412—Shape
Definitions
- the present invention relates to a printhead for a thermal ink-jet printer, and more particularly to an ejector in which droplets of distinctly selectable sizes may be ejected.
- US-A-4,251,824 discloses a thermal ink-jet printhead wherein each ejector includes a plurality of independently-controlled heating elements. By selecting a particular combination of elements, one can select,the size of the ejected droplet.
- US-A-4,740,796 discloses basic principles of bubble nucleation in ink-jet printing. It is also generally known that one technique for manipulating the size of ink droplets is to control the temperature of the liquid ink just before nucleation, such as by preheating the liquid ink to a predetermined temperature which will yield a known droplet size.
- an ejector for an ink-jet printing apparatus A structure defines a channel that retains a quantity of liquid ink therein. An opening is associated with the channel, through which a quantity of liquid ink may be ejected.
- a heating element defines the heating surface within the channel, the heating element dissipating heat into the channel when voltage is applied thereto, thereby nucleating a bubble in liquid ink in the channel.
- the heating surface defines a first portion adapted to dissipate heat at a first power density and a second portion adapted to dissipate heat at a second power density.
- Figure 1 is a highly simplified perspective view showing the portions of an ejector for a thermal ink-jet printhead incorporating the present invention. Although only one ejector is shown, it will be understood that a practical thermal ink-jet printhead will include 100 or more such ejectors, typically spaced at 118 to 336 ejectors per cm (300 to 600 ejectors per inch). Illustrated in Figure 1 is the general configuration of what is known as a "side-shooter" printhead wherein the channels forming the ejectors are created between two chips which are bound together.
- the printhead shown in Figure 1 comprises a heater chip 10, which is bound on a main surface thereof to a "channel plate" indicated in phantom as 12.
- the heater chip 10 is generally a semiconductor chip design as known in the art, and defines therein any number of heating elements, such as indicated as 14, on a main surface thereof. There will typically be provided one heating element 14 for every ejector in the printhead. Adjacent each ejector 14 on the main surface of heater chip 10 is a channel 16 which is formed by a groove in channel plate 12. Channel plate 12 can be made of any number of ceramic, plastic, or metal materials known in the art. When the chip 10 is abutted against the channel plate 12, each channel 16 forms a complete channel with the adjacent surface of the heater chip 10, and one heating element 14 disposes a heating surface on the inside of the channel so formed, as shown in Figure 1.
- Figure 1 shows a highly simplified version of a practical thermal ink-jet printhead, and that any number of ink supply manifolds, intermediate layers, pit layers, etc., would be provided in a practical printhead.
- Figure 1 shows the essential elements necessary to practice the present invention, and the addition of further elements to make a fully practical printhead will not detract from the claimed invention as described in detail below.
- an ink supply manifold (not shown) provides liquid ink which fills the capillary channel 16 until it is time to eject ink from the channel 16 onto a print sheet.
- a small voltage is applied to heating element 14 in heater chip 10.
- heating element 14 is typically a portion of a semiconductor chip which is doped to a predetermined resistivity. Because heating element 14 is essentially a resistor, heating element 14 dissipates power in the form of heat through its heating surface (the heating surface being defined as the surface of heating element 14 disposed within channel 16), thereby vaporizing liquid ink immediately adjacent the heating surface.
- Figure 2 is a plan view of a portion of the main surface of heater chip 10, showing in detail the heating surface provided by one heating element 14, as would be found in a single ejector according to the present invention. Also shown in Figure 2, in phantom lines, are the borders of the channel formed by channel 16 in channel plate 12 when it is bound to the main surface of heater chip 10.
- an input line is shown as 20, and creates a first terminal where input line 20 attaches to heating element 14.
- a ground line 22 is attached to each heating element 14 and a ground line 22, forming a second terminal where it meets heating element 14, which connects heating element 14 to a common ground 24.
- the ground lines 22 associated with all of the heating elements 14 on a particular chip share common ground line 24. Therefore, any control over the timing and manner of applying a voltage to any heating element 14 must be via input line 20, which is why an ejector of the present design can be considered a "single-terminal" ejector.
- an input line such as 20 is ultimately controlled by electrical signals relating to digital data representative of an image desired to be printed.
- the heating element 14 defines a heating surface of a general "bottle" shape, here defining two distinct, and generally rectangular, portions.
- a first portion of the heating surface is generally indicated as 30, while a second portion of the heating surface is generally indicated as 32.
- the two portions 30, 32 are generally aligned along an axis formed by input line 20 and ground line 22, an axis which also is parallel to the general direction of the channel formed by channel 16, and thereby aligned with the opening formed by channel 16.
- the heating element 14 provides a heating surface within channel 16 of such properties that each portion dissipates energy, in the form of heat, at a particular power density which is different from the power density of another portion.
- Power density can be defined as the amount of energy dissipated from the heating surface per unit area.
- nucleation of liquid ink in a channel is brought about essentially as follows.
- a voltage must be applied to the heating element sufficient to drive the liquid ink adjacent the heating surface to vaporization (the "burn voltage"), and this burn voltage must be applied for a suitable duration of time (“pulse width").
- a relatively low burn voltage can be compensated for by extending the pulse width and vice-versa.
- nucleation will occur only around that portion of the heating surface having the necessary power density by which a combination of burn voltage and pulse width will be sufficient to nucleate ink immediately adjacent the heating surface. Power density multiplied by time equals energy density, and nucleation occurs only over those surfaces having this sufficent energy density.
- the layout of the heating surface of heating element 14, which is an area of a particular shape doped to a uniform resistivity, provides two distinct portions 30 and 32 which will satisfy the requirements of burn voltage and/or pulse width separately.
- a first predetermined voltage V 1 is applied to heating element 14, for a predetermined pulse width
- the layout of the heating surface will be such that only the area over the portion 30 of the heating surface will be able to meet the requirements of pulse width and burn voltage; the second portion 32, being of larger area, will have no particular area therein which meets the requirements of power dissipation for nucleation.
- first portion 30, dissipating the energy of V 1 over a smaller area, will provide a higher power density than the larger second portion 32 being subjected to the same voltage V 1 . Therefore, at a certain voltage V 1 , only the liquid ink immediately adjacent portion 30 of the heating surface will nucleate, resulting in a relatively small ink vapor bubble, indicated as 40.
- the size of the nucleated liquid ink bubble in a channel is roughly proportional to the amount of liquid ink that is expelled by creation of the bubble. Therefore, the larger the nucleated liquid ink bubble, the larger the droplet of ink that will be ejected, and the larger the resulting spot size on the print sheet.
- the size of the nucleation bubble By selecting the size of the nucleation bubble, the size of the resulting droplet ejected through the opening of channel 16 can be selected, in this case between a small droplet (nucleation bubble 40 in Figure 3) or a large droplet (nucleation bubble 42 in Figure 4).
- FIG. 5 is a simplified graph showing the relationship of the voltage applied to the heating element 14, on the x axis thereof, to the resulting nucleation bubble volume on the y axis.
- the numbers 40, 42 on the y axis represent the respective volumes of the nucleation bubbles 40, 42 shown in Figures 3 and 4.
- the basic line of the graph is a "stairstep" function which flattens in two distinct areas, which correspond on the x axis to acceptable ranges for V 1 and V 2 respectively.
- An advantage of the stairstep function which is provided by the discrete demarcation between portions 30, 32 of the heating surface, is that the necessary burn voltages V 1 or V 2 can be provided within reasonably broad ranges as shown on the x axis of Figure 5. Whether, for example, the actual value of applied V 1 is closer to the left or right of the range in the graph of Figure 5, the size of the nucleation bubble which results will not significantly vary. This tolerance for a wide range of actual applied voltages is an important attribute in semiconductor-based heater chips 10, with the actual on-chip voltage (or the power density in response to a given voltage) can vary significantly from chip to chip and on a single chip over time.
- heating element 14 were a monotonic shape, such as a single triangle or an ovoid, it is likely the function of voltage to volume would not be the stairstep shown in Figure 5, but rather a substantially linear function. While a substantially linear function would have theoretical advantages of providing a continuously-variable spot size as a function of voltage, the ejector-to-ejector and chip-to-chip variances in performance would make such a continuously-variable system impractical, particularly in a printer having a number of printhead chips.
- Figure 5 shows a change in bubble volume as a function of applied voltage and presuming a constant pulse width
- a generally similar function to Figure 5 will result if the applied voltage is held constant and the pulse width, or duration, of the voltage is varied.
- the same principle shown in Figures 3 and 4 with different voltages will also be generally apparent if the same voltage is applied to the heating element 14 at two different pulse widths. Therefore, systems could be provided which are able to choose the bubble size, and therefore droplet size, by selecting either the burn voltage or the pulse width, or both.
- FIG. 6 is a simplified plan view of another possible embodiment of the present invention, wherein a different principle is used to,obtain the desired result of different power densities in different portions of the heating element.
- a heating element indicated as 14' which functions in the same way between control line 20 and ground line 22 as in the above embodiment, comprises different distinct resistive sections 50, 52, 54, 56, and 58, each of which is made of doped polysilicon, but wherein each individual section 50-58 is doped to a different resistivity.
- the sections such as 50 closer to the ground line 22 and opening in the channel are doped to a higher resistivity, with the resistivities becoming progressively lower toward input line 20.
- Sections doped to a higher resistivity will tend to nucleate the adjacent liquid ink at lower voltages, or at shorter pulse widths.
- the relative sizes of the differently-doped sections 50-58 can be manipulated to obtain different selectable bubble sizes, which result in different resulting spot sizes.
- the present example in Figure 6 shows five distinct different-doped sections, which correspond to a single heating element 14' which is responsive to five different applied voltages or pulse widths to cause the output of five distinctly different droplet sizes.
- the overall dimension of the heating surface, including all of the portions thereof is approximately 200 micrometers by 20 micrometers.
- a preferred protective covering within the channel 16 for a heating element such as 14 is tantalum. Tantalum is a good thermal conductor, which would act against the desired effect of restricting nucleation to specific portions of the heating surface.
- Possible solutions to this problem include using a protective material other than tantalum, thinning the tantalum layer, or even providing "shims" (not shown) within the protective layer over the borders between adjacent portions, these shims acting as thermal insulators.
- Possible materials for such shims include phosphosilicate glass, or polyimide.
- FIG. 7 shows a heating element 14 which is demarcated into four distinct portions, adding portions 34 and 36 to the portions 30 and 32 described in detail above.
- a heating element 14 would be responsive to four burn voltages or pulse widths and therefore be able to nucleate bubbles of four distinct sizes.
- the two general principles of defining separate portions of a heating surface such as demarcating a uniformly-doped heating surface with "shoulders" or doping different portions of the heating surface for different resistivities, could be combined in a heating element which incorporates both techniques.
- a heating surface as shown and described comprises substantially rectangular portions, it will be apparent that other general shapes for individual portions, such as round or triangular, could be provided. These alternate shapes are functional equivalents to the preferred rectangular shapes.
- the important principle is that the overall shape of the heating surface, or the profile of relative resistivities, have portions of the heating surface organized in discrete sections, as opposed to a gradual or monotonic change.
- the illustrated embodiment shown depicts different portions such as 30, 32 or 50, 52 directly bordering each other in a single-piece heating element, it is not a necessity that the different portions directly abut each other.
- the different portions could be spaced apart within channel 16 and only be connected through a connector within the heater chip 10.
- different portions of what is electrically a single heating element 14 could be provided on different surfaces (such as provided by two separate chips) forming some of the walls of the channel.
Landscapes
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US609268 | 1984-05-11 | ||
US60926896A | 1996-02-29 | 1996-02-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0792745A2 true EP0792745A2 (fr) | 1997-09-03 |
Family
ID=24440051
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19970301275 Withdrawn EP0792745A2 (fr) | 1996-02-29 | 1997-02-26 | Tête d'enregistrement à jet d'encre |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0792745A2 (fr) |
JP (1) | JPH09234867A (fr) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1078757A3 (fr) * | 1999-08-24 | 2001-08-08 | Canon Kabushiki Kaisha | Tête d'éjection de liquide, méthode pour son entrainement, cartouche et appareil de formation d'image |
US7178904B2 (en) | 2004-11-11 | 2007-02-20 | Lexmark International, Inc. | Ultra-low energy micro-fluid ejection device |
WO2019143323A1 (fr) | 2018-01-17 | 2019-07-25 | Hewlett-Packard Development Company, L.P. | Ensembles de fluides |
-
1997
- 1997-02-24 JP JP3954797A patent/JPH09234867A/ja not_active Withdrawn
- 1997-02-26 EP EP19970301275 patent/EP0792745A2/fr not_active Withdrawn
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1078757A3 (fr) * | 1999-08-24 | 2001-08-08 | Canon Kabushiki Kaisha | Tête d'éjection de liquide, méthode pour son entrainement, cartouche et appareil de formation d'image |
US6443561B1 (en) | 1999-08-24 | 2002-09-03 | Canon Kabushiki Kaisha | Liquid discharge head, driving method therefor, and cartridge, and image forming apparatus |
US7178904B2 (en) | 2004-11-11 | 2007-02-20 | Lexmark International, Inc. | Ultra-low energy micro-fluid ejection device |
WO2019143323A1 (fr) | 2018-01-17 | 2019-07-25 | Hewlett-Packard Development Company, L.P. | Ensembles de fluides |
US11254832B2 (en) | 2018-01-17 | 2022-02-22 | Hewlett-Packard Development Company, L.P. | Fluid sets |
Also Published As
Publication number | Publication date |
---|---|
JPH09234867A (ja) | 1997-09-09 |
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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 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB |
|
18W | Application withdrawn |
Withdrawal date: 19970730 |
|
RHK1 | Main classification (correction) | ||
RHK1 | Main classification (correction) |
Ipc: B41J 2/14 |