Inkjet printhead architecture for high speed and high resolution printing

• US 5,648,805 A
• Filed: 10/06/1994
• Issued: 07/15/1997
• Est. Priority Date: 04/02/1992
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Ho, May Fong, Childers, Winthrop D., Steinfield, Steven W., Trueba, Kenneth E., Courian, Kenneth J., Moritz, Jules G., Knight, William R., Keefe, Brian J., Chapman, Terri I., Tappon, Ellen R.
• Primary Examiner(s): ROYER, WILLIAM J
• Application Number:
  US08/319,896
• Time in Patent Office: 1,013 Days
• Field of Search: 347/47-48, 347/50, 347/58-59, 347/65, 347/55, 347/20
• US Class Current: 347/65
• CPC Class Codes: B41J 2/04511 for electrostatic discharge protection
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04546 Multiplexing
• CPC Class Codes: B41J 2/0458 controlling heads based on heating elements forming bubbles
• CPC Class Codes: B41J 2/14024 Assembling head parts
• CPC Class Codes: B41J 2/1404 Geometrical characteristics
• CPC Class Codes: B41J 2/14072 Electrical connections, e.g. details on electrodes, connecting the chip to the outside...
• CPC Class Codes: B41J 2/14129 Layer structure
• CPC Class Codes: B41J 2/14145 Structure of the manifold
• CPC Class Codes: B41J 2/14201 Structure of print heads with piezoelectric elements
• CPC Class Codes: B41J 2/1433 Structure of nozzle plates
• CPC Class Codes: B41J 2/1603 of the front shooter type
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1626 etching
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1634 laser machining
• CPC Class Codes: B41J 2/1635 dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/175 : Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17509 : Whilst mounted in the printer
• CPC Class Codes: B41J 2/17513 : Inner structure
• CPC Class Codes: B41J 2/1752 : Mounting within the printer
• CPC Class Codes: B41J 2/17523 : Ink connection
• CPC Class Codes: B41J 2/17526 : Electrical contacts to the cartridge
• CPC Class Codes: B41J 2/1753 : Details of contacts on the cartridge, e.g. protection of contacts
• CPC Class Codes: B41J 2/17553 : Outer structure
• CPC Class Codes: B41J 2/17556 : Means for regulating the pressure in the cartridge
• CPC Class Codes: B41J 2002/14387 : Front shooter
• CPC Class Codes: B41J 2202/13 : Heads having an integrated circuit

Abstract

An improved ink flow path between an ink reservoir and ink ejection chambers in an inkjet printhead is disclosed along with a preferred printhead architecture. In the preferred embodiment, a barrier layer containing ink channels and firing chambers is located between a rectangular substrate and a nozzle member containing an array of orifices. The substrate contains two spaced apart arrays of ink ejection elements, and each orifice in the nozzle member is associated with a firing chamber and ink ejection element. The ink channels in the barrier layer have ink entrances generally running along two opposite edges of the substrate so that ink flowing around the edges of the substrate gain access to the ink channels and to the firing chambers. High speed printing capability with a firing frequency up to 12 KHz is accomplished by offsetting neighboring ink ejection elements from each other in each primitive grouping in the linear array, combining short shelf length with damped ink inlet channels, and then firing only one ink ejection element at a time in each primitive grouping thereby minimizing undesirable interference such as fluidic crosstalk between closely adjacent ink firing chambers. High resolution printing capability for at least 600 dots-per-inch by the printhead as a whole is accomplished by densely positioning the ink ejection elements in each linear array of ink ejection elements.

Claims

1. A printing system for an inkjet printer comprising:

a supply of ink in an ink reservoir;

a printhead substrate having a top surface and an opposing bottom surface, and having a first outer edge along a periphery of said substrate;

a printhead nozzle member having a plurality of ink orifices formed therein, said nozzle member being positioned to overlie said top surface of said substrate;

a plurality of ink ejection elements formed on said top surface of said substrate, each of said ink ejection elements being located proximate to an associated one of said orifices for causing a portion of said ink to be expelled from said associated orifice; and

a fluid channel, communicating with said ink reservoir, leading to each of said orifices and said ink ejection elements, said fluid channel allowing said ink to flow from said ink reservoir, along a portion of said bottom surface of said substrate, around said first outer edge of said substrate, and to said top surface of said substrate so as to be proximate to said orifices and said ink ejection elements, wherein said fluid channel includes ink channels formed over said top surface of said substrate for directing ink to each of said ink ejection elements.

2. The printing system of claim 1 wherein said fluid channel comprises a plurality of ink ejection chambers, said ink channels communicating between said ink reservoir and said ink ejection chambers, each of said ink ejection chambers being associated with an ink orifice and an ink ejection element, with adjacent ink orifices offset from each other in a scan direction of said printhead nozzle member across a medium.

3. The printing system of claim 2 wherein said substrate also has a second outer edge, and said fluid channel allows said ink to flow around said first outer edge and said second outer edge of said substrate and into said ink channels so as to deliver said ink from said ink reservoir to said ink ejection chambers.

4. The printing system of claim 2 wherein an entrance to each of said ink channels is constructed to provide an increased surface area for supporting said nozzle member when said nozzle member is positioned on a top surface of said substrate overlying said ink channels.

5. The printing system of claim 2 which further includes a plurality of ink supply cavities formed as part of said ink channels, each of said cavities being formed proximate to each of said orifices, each of said cavities being located to enlarge the ink volume capacity of said ink channels when said nozzle member is positioned on a top surface of said substrate to facilitate the refill of said ink into said ink ejection chambers.

6. The printing system of claim 1 wherein said fluid channel is formed in a barrier layer between said substrate and said nozzle member, said barrier layer also forming constriction means in said ink channels for damping said ink in said fluid channel.

7. The printing system of claim 6 wherein said barrier layer is separate from said nozzle member and is secured to a back surface of said nozzle member to provide a separation wall between adjacent ink election elements, and wherein said ink ejection elements are positioned to provide a printing resolution of at least 300 dots per inch.

8. A method for inkjet printing comprising the steps of:

providing a substrate, having a top surface and a bottom surface, with ink ejection chambers formed on said top surface grouped to form a plurality of primitives;

supplying ink from an ink reservoir along a portion of said bottom surface of said substrate, around one or more edges of said substrate'"'"'s periphery and to a top surface of said substrate to allow the ink, which has flowed around said one or more of said edges, to enter said ink ejection chambers, each ink ejection chamber substantially surrounding an ink ejection element formed on said top surface of said substrate; and

energizing one of more of said ink ejection elements to cause a portion of the ink in associated ones of said ink ejection chambers to be expelled from said orifices.

9. The method of printing of claim 8 which further includes positioning the ink ejection chambers in each primitive to be offset from each other in a carriage scan direction of said substrate accross a medium.

10. The method of printing of claim 8 wherein said step of supplying ink includes supplying the ink from an ink reservoir around at least two edges of the substrate'"'"'s periphery.

11. The method of printing of claim 10 wherein a first primitive includes a first array of ink ejection chambers grouped along one of the at least two edges, and a second primitive includes a second array of ink ejection chambers grouped along another of the at least two edges.

12. The method of printing of claim 8 wherein said energizing step includes energizing only one at a time said ink ejection elements which are grouped in a given primitive.

13. The method of printing of claim 12 wherein said energizing step includes energizing said ink ejection elements which are grouped in a given primitive in a predetermined sequence such that no adjacent ink ejection elements are successively energized.

14. The method of printing of claim 8 which further includes transporting the ink past at least one protruding damping wall prior to the ink entering said ink ejection chambers.

15. The method of printing of claim 8 which further includes providing a separate ink channel for carrying the ink into each ink ejection chamber.

16. The method of printing of claim 15 which further includes providing a channel shelf along said one or more of said edges for carrying the ink to the separate ink channels.

17. An inkjet printing system comprising:

a reservoir;

a supply of ink in said reservoir;

a printhead substrate having a top surface and an opposing bottom surface, said substrate having a plurality of ink firing chambers with ink ejection elements located therein located on said top surface of said substrate, said ink ejection elements spaced apart from each other a predetermined distance to provide a printing resolution of 300 dots per inch or greater;

fluid channels extending between said reservoir and said ink firing chambers in order to transport said ink along a portion of said bottom surface of said substrate and around one or more edges of said substrate, said substrate including a group of said ink ejection elements forming a primitive; and

demultiplexing circuitry on said substrate and connected to said ink ejection elements for selectively firing said ink ejection elements.

18. The printing system of claim 17 wherein said demultiplexing circuitry includes gates for selectively firing said ink ejection elements in a primitive one-at-a-time.

19. The printing system of claim 17 wherein said demultiplexing circuitry has a firing frequency of at least 8 KHz or greater.

20. The printing system of claim 17 wherein said ink ejection elements in said primitive are offset from each other in a carriage scan direction.