Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1999-09-22
2001-11-06
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06312079
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to ink jet printers. More particularly, the invention relates to a method and apparatus for addressing and firing the nozzles on an ink jet print head cartridge that minimizes the data lines necessary to address the nozzles.
BACKGROUND OF THE INVENTION
An ink jet print head cartridge has a number of nozzles on a substrate that are used to expel drops of ink onto a printing surface. As the print head cartridge scans across a printing surface, the nozzles are fired at precisely determined times to expel drops of ink and produce an image on the printing surface. In order to decrease the time required to print an image or increase the resolution of a printed image, larger and larger numbers of nozzles are being placed on modern ink jet print head cartridges. As the number of nozzles on the print head increases, the number of input data lines required to address and fire the nozzles also increases. Unfortunately as the number of input lines to the ink jet print head increases, so does the cost and complexity of manufacturing the print head. In addition, the increasing complexity of the connections between the printer electronics and the ink jet print head leads to a decrease in the manufacturing yield when producing the print head. Thus, there is a need to reduce the number of data lines between an ink jet print head cartridge and the printer electronics of an ink jet printer.
SUMMARY OF THE INVENTION
Therefore, the present invention provides a method and apparatus for firing the nozzles of an ink jet print head that requires a reduced number of data lines to address and fire a particular selected nozzle out of a given number of nozzles on the print head.
With regard to the foregoing, the present invention provides a method of firing the nozzles of an ink jet print head cartridge that includes the step of generating and supplying serial group selection data, serial primitive selection data, and a fire pulse to the print head cartridge. A group of nozzles is selected based upon the serial group selection data. Particular nozzles within the selected group of nozzles are selected based upon said serial primitive data. The selected particular nozzles are fired based in part on the firing pulse.
Preferably, the above discussed method further includes the steps of storing the serial group selection data on the ink jet print head cartridge in a first memory and storing the serial primitive selection data on the print head cartridge in a second memory. The serial group selection data and the serial primitive data are advanced into the first memory and the second memory in accordance with a first clock signal. The serial group selection data is decoded to produce selected group result data. A logical AND or a logical NAND operation is performed on the selected group result data and the serial primitive data stored in the first memory and the second memory to produce firing data. The firing data is advanced into a firing memory in accordance with a second clock signal. The selected particular nozzles are fired by performing a logical AND or a logical NAND operation on the firing data and the firing pulse to fire the selected particular nozzles.
Addressing the nozzles of an ink jet print head by providing serial group selection data that indicates a particular group of nozzles and serial primitive selection data that indicates individual nozzles to be activated within the selected group allows the nozzles to be addressed in any sequence and requires less input lines than prior art approaches. In addition, the method provides speed advantages over prior art approaches that send all of the nozzle firing data serially over a single data line. Thus, the above described method represents a substantial improvement over prior art methods of addressing the nozzles of an ink jet print head.
Another embodiment of the present invention is directed toward an apparatus for communicating firing information to a print head having a plurality of ink firing elements. The apparatus includes data processing means for producing group selection data, primitive selection data, and a fire pulse. A group data line serially supplies the group selection data to the print head and a primitive data line serially supplies the primitive selection data to the print head. A fire pulse line supplies a fire pulse to the print head. Group selecting means on the print head select a group of firing elements from the plurality of firing elements based upon the serial group selection data. Primitive selecting means on the print head select particular firing elements within the group of firing elements based upon the primitive selection data. Firing means fire the particular firing elements based in part on the firing pulse.
The present invention further comprehends an embodiment wherein the apparatus has a set of group selection latches on the print head for storing the serial group selection data. A set of primitive latches on the print head store the primitive selection data. A first clock line supplies a first clock signal that is used to advance the serial group selection data into the set of group selection latches and the primitive selection data into the set of primitive latches. In this embodiment, the group selection data is a group address and the group selecting means comprise a decoder for receiving the group address from the group selection latches and decoding the group address to produce a selected group signal that contains a logical selection state for each group of firing elements. Firing element selection logic means perform a logical AND or a logical NAND operation on the selected group signal and the primitive selection data to produce firing data that contains a logical selection state for each firing element. A second clock line supplies a second clock signal that is used to advance the firing data to a set of firing latches that store the firing data. There is one firing latch that corresponds to each firing element. Firing logic means perform a logical AND or a logical NAND operation on the stored firing data and the firing pulse to fire the selected firing elements.
In an alternative embodiment the group selection data contains a logical selection state for each group of firing elements and the group selecting means comprise group bus lines for addressing the selected group. In addition, the primitive selecting means comprise primitive bus lines for addressing the selected firing elements within the selected group. Logic means perform a logical ANDing of the group selection data and the primitive selection data to determine the particular firing elements to be activated.
The present invention also comprehends an embodiment having a first and a second primitive data line. In such an embodiment, the primitive selection data includes first primitive selection data and second primitive selection data. The first primitive data line supplies the first primitive selection data to the print head and the second primitive data line supplies the second primitive selection data to the print head. The provision of two primitive data lines allows a greater number of primitive data bits to be supplied to the ink jet print head in a reduced amount of time.
The present invention further envisions a method of individually addressing and firing nozzles on an ink jet print head with a reduced number of data lines wherein the nozzles are arranged into a plurality of groups each having a plurality of nozzles and wherein the nozzles can be addressed and fired in any order. The method includes the step of serially providing group select data containing the address of a selected group of nozzles to the ink jet print head on a group data line. In addition, primitive select data containing a logical selection state for each of the plurality of nozzles in the selected group of nozzles is serially provided to the ink jet print head on a primitive data line. The group select data is decoded to determine a logical selection state for each group of nozzles. One of a logical ANDing
Anderson Frank Edward
Eade Thomas Jon
Parish George Keith
Barlow John
Hallacher Craig A.
Lexmark International Inc.
Luedeka Neely & Graham
LandOfFree
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