In thermal inkjet printing systems, a thermal inkjet (TIJ) printhead typically ejects printing fluid drops from a reservoir through a plurality of nozzles onto a print medium. The nozzles are typically arranged in one or more arrays or columns such that properly sequenced ejection of printing fluid from the nozzles causes intended images to be printed on a print medium as the printhead and/or print medium move relative to each other. TIJ printheads eject printing fluid drops from a nozzle by passing electrical current through a heating element, which generates heat and vaporizes a small portion of the printing fluid within a firing chamber. The rapidly expanding vapor bubble forces a small amount of printing fluid to drop out of the nozzle. When the heating element cools, the vapor bubble quickly collapses, drawing more printing fluid from the reservoir into the firing chamber.
During printing, heat from the heating elements as well as the physical configuration and thermal characteristics of the TIJ die affect the temperature of the TIJ die. For instance, the areas, e.g., ends, of the TIJ die that do not contain heating elements often act as heat sinks and thus pull heat from locations in the TIJ die containing heating elements. Thermal differences over the nozzle column area of the TIJ die have a significant influence on characteristics of the printing fluid drops being fired from the nozzles. For example, a higher die temperature results in a higher drop weight and drop velocity, while a lower die temperature results in a lower drop weight and velocity. Thus, variations in temperature across the die have been known to result in variations in drop weight, velocity and shape, which have been known to have a considerable impact on print quality. For example, drops with lower drop weight ejected from cooler areas of the die have been known to result in printed areas on the print medium that have less printing fluid than intended. The areas printed with less printing fluid will appear to be lighter than other areas printed with drops of higher drop weight ejected from warmer areas of the die. In general, print quality problems associated with inconsistent drop characteristics caused by variations in temperature across the TIJ die are referred to as light area banding (LAB), die boundary banding (DBB), and hue shift.
Features of the present disclosure are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which:
For simplicity and illustrative purposes, the present disclosure is described by referring mainly to an example thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be readily apparent however, that the present disclosure may be practiced without limitation to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the present disclosure. As used herein, the terms “a” and “an” are intended to denote at least one of a particular element, the term “includes” means includes but not limited to, the term “including” means including but not limited to, and the term “based on” means based at least in part on.
Disclosed herein are methods for enhancing temperature distribution uniformity across a printer die and apparatuses for implementing the methods. In the methods, a warming map that identifies the drop generators of a plurality of drop generators that are to be supplied with warming pulses to enhance temperature distribution uniformity across the printer die may be accessed. The warming map may identify a non-uniform distribution of the drop generators across a column of a plurality of columns. In addition, the warming map may be implemented to supply the drop generators identified in the warming map as the drop generators that are to receive the warming pulses.
Through implementation of the methods and apparatuses disclosed herein, temperature distribution uniformity across a printer die may be enhanced. In one regard, therefore, the methods and apparatuses disclosed herein may enable the drop generators of a printer die to drop substantially equivalently sized drops of printing fluid and thus substantially enhance a print quality of the printer die.
With reference first to
As shown in
Each of the print slots 108-114 is depicted as including a plurality of drop generators 116 arranged along two parallel columns. The drop generators 116 are depicted as being arranged along a first drop generator column 115a and a second drop generator column 115b. A relatively small number of drop generators 116 is shown for convenience, but it should be clearly understood that each of the print slots 108-114 may include much larger numbers of drop generators 116, for instance, to be able to print at 600 dpi or more across the width of a media 130. Each of the drop generators 116 may be a resistor (or equivalently, a heating element) that may be energized to cause drops of printing fluid to be ejected out of respective nozzles (an example is shown in
As discussed in greater detail herein below, the controller 102 also includes a warming map implementing apparatus 104 that is to access a warming map that identifies the drop generators 116 of the printer die 106 that are to be supplied with warming pulses to warm the printer die during a warming operation, in which the warming map identifies a non-uniform distribution of the drop generators 116 across a column of the plurality of columns that are to be supplied with the warming pulses. The warming pulse may include a precursor pulse without a firing pulse. As discussed herein, a distribution of drop generators 116 across a column 115a of drop generators 116 that are to be supplied with the warming pulses may be construed as being non-uniform when a larger number of drop generators 116 in a particular section of the drop generators 116 as compared with the number of drop generators 116 in another section are included in the distribution of the drop generators that are to be supplied with the warming pulses. Thus, for instance, a distribution in which every other drop generator 116 along a column of drop generators 116 is identified in a warming map to receive warming pulses during a warming operation may be construed as being a warming map having a uniform distribution of drop generators 116 that are to be supplied with warming pulses.
In addition, the warming map implementing apparatus 104 may supply the drop generators 116 identified in the warming map as drop generators that are to receive warming pulses during a warming operation with the warming pulses during the warming operation. According to an example, the warming map implementing apparatus 104 supplies the drop generators 116 identified in the warming map with warming pulses, e.g., supplies precursor pulses without supplying firing pulses. As such, the warming map implementing apparatus 104 may not supply the drop generators 116 identified in the warming map with firing pulses to cause printing fluid to be ejected out of nozzles during a warming operation. Instead, the duration of the pulses supplied to the drop generators 116 identified in the warming map may only be sufficient to heat printing fluid, and thus a section of printer die 106, around the identified drop generators 116.
As also shown in
Turning now to
As shown in
According to an example, the drop generator 116 is a resistor that is energized, e.g., heated, through receipt of an electrical signal through a signal line 128. A simplified example of a manner in which signal lines 128 may be connected between the controller 102 and the drop generators 116, according to an example, is depicted in
Particularly, during a printing operation, the drop generator 116 may receive an ejection pulse, e.g., both a precursor pulse and a firing pulse, to cause a bubble to be formed in the printing fluid 118 contained in the printing fluid chamber 122, which may cause a printing fluid drop 126 to be ejected through the nozzle 124. During a warming operation, the drop generator 116 may receive a warming pulse, e.g., a precursor pulse without a firing pulse. As such, during the warming operation, the drop generator 116 may heat the printing fluid 118 in the printing fluid chamber 122 without causing a printing fluid drop 126 from being ejected through the nozzle 124. The heating of the printing fluid 118 may also cause areas in the printer die 106 that are near the heated printing fluid 118 to also become heated. As discussed herein, the drop generators 116 that are supplied with the warming pulses to thus heat intended areas of the printer die 106 are identified in a warming map. In addition, because a non-uniform temperature distribution may exist across a printer die 106, the warming map may identify a non-uniform distribution of drop generators 116 that are to receive the warming pulses. That is, for instance, the warming map may identify the drop generators 116 that are located near areas of the printer die 106 that have relatively lower temperatures as the drop generators that are to be supplied with the warming pulses.
By way of particular example in which heat is known to be dissipated at a faster rate at the ends of the printer die 106 and thus the ends of the printer die 106 have relatively lower temperatures than the middle section of the printer die 106, the warming map may include a larger number of drop generators 116 that are to be supplied with the warming pulses at the ends of the printer die 106 as compared with the number of drop generators 116 located near the middle section of the printer die 106. Furthermore, the warming map may indicate that only the drop generators 116 located at the ends of the printer die 106 are to be supplied with the warming pulses and that the drop generators 116 located near the middle of the printer die 106 are not to receive the warming pulses during a warming operation.
During a printing operation, the controller 102 may selectively activate the drop generators 116 according to a proper sequence as the media 130 is fed in the feed direction 132 to cause printing fluid drops 126 to be dropped at the appropriate locations on the media 130. According to an example, the controller 102 may also cause the printer die 106 to be scanned in a direction perpendicular to the feed direction 132 during a printing operation. In addition, the drop generators 116 may be selectively energized to form a desired image on the media 130. The desired image may include any of text, pictures, lines, drawings, filled-in drawings, etc.
Turning now to
As shown in
The processor 202, which may be a microprocessor, a micro-controller, an application specific integrated circuit (ASIC), or the like, is to perform various processing functions in the controller 102. The processing functions may include invoking or implementing the warming map implementing apparatus 104 and particularly, the modules 210 and 212 of the warming map implementing apparatus 104, as discussed in greater detail herein below. According to an example, the warming map implementing apparatus 104 is a hardware device on which is stored various sets of machine readable instructions. The warming map implementing apparatus 104 may be, for instance, a volatile or non-volatile memory, such as dynamic random access memory (DRAM), electrically erasable programmable read-only memory (EEPROM), magnetoresistive random access memory (MRAM), memristor, flash memory, floppy disk, a compact disc read only memory (CD-ROM), a digital video disc read only memory (DVD-ROM), or other optical or magnetic media, and the like, on which software may be stored. In this example, the modules 210 and 212 may be software modules, e.g., sets of machine readable instructions, stored in the warming map implementing apparatus 104.
In another example, the warming map implementing apparatus 104 may be a hardware component, such as a chip, an integrated circuit, etc., and the modules 210 and 212 may be hardware modules on the hardware component. In a further example, the modules 210 and 212 may include a combination of software and hardware modules. In a yet further example, the processor 202 may be an ASIC that is to perform the functions of the modules 210 and 212. In this example, the processor 202 and the warming map implementing apparatus 104 may be a single processing apparatus.
The processor 202 may store data in the data store 206 and may use the data in implementing the modules 210 and 212. For instance, the processor 202 may store data pertaining to an image that is to be printed onto a medium 130. In any regard, the data store 206 may be volatile and/or non-volatile memory, such as DRAM, EEPROM, MRAM, phase change RAM (PCRAM), memristor, flash memory, and the like. In addition, or alternatively, the data store 206 may be a device that may read from and write to a removable media, such as, a floppy disk, a CD-ROM, a DVD-ROM, or other optical or magnetic media.
The signal line interface 204 may include hardware and/or software to enable the processor 202 to respectively send electrical signals to the drop generators 116 over signal lines 128. Although not shown, the signal line interface 204 may be connected to a power source from which the electrical signals may be transmitted to the respective drop generators 114. In addition, the processor 202 may be connected to an input/output interface (not shown) that may enable the processor 202 to access a network, such as an internal network, the Internet, etc., over which the processor 202 may receive files containing images to be printed. The input/output interface may include a network interface card and/or may also include hardware and/or software to enable the processor 202 to communicate with various input and/or output devices, such as a keyboard, a mouse, a display, another computing device, etc., through which a user may input instructions into the printing system 100.
Various manners in which the processor 202 in general, and the modules 210 and 212 in particular, may be implemented are discussed in greater detail with respect to the method 300 depicted in
The description of the method 300 is made with reference to the printing system 100 illustrated in
With reference to the method 300 depicted in
According to an example, the warming map accessing module 210 may access the warming map from the data store 206. In another example, the warming map may be firmware and the warming map accessing module 210 may access the warming map, which may be hardcoded on the warming map implementing apparatus 104.
At block 304, the warming map may be implemented to supply the drop generators 116 identified in the warming map as the drop generators that are to receive the warming pulses. Particularly, the drop generator warming pulse supplying module 212 may supply the drop generators 116 identified in the warming map as the drop generators that are to receive the warming pulses over respective signal lines 128. The warming pulses may be a continuous series of pulses that have pulse widths of sufficiently short durations so that the energy of the pulses is insufficient to cause a deposition of a printing fluid drop from a nozzle 124 of a print slot 108. By way of particular example, a warming pulse may have a duration of around 400 nanoseconds, whereas a firing pulse, which is of sufficient duration to cause a printing fluid drop 126 to be dropped, may have a duration of around 1000 nanoseconds. In addition, an ejection pulse may include a precursor pulse having a duration of around 400 nanoseconds with a delay of about 600 nanoseconds between the precursor pulse and the firing pulse.
Turning now to
In
Although the warming maps in
According to an example, the warming maps 400-600 may be generated through testing of the performance of the drop generators 116. That is, a set of printing fluid printed by the printer die 106 may be examined to determine which of the drop generators 116 may have deposited relatively smaller drops of printing fluid as compared with the other drop generators 116. Those drop generators 116 that have deposited relatively smaller drops of material may be identified in a warming map as being the drop generators 116 that are to be supplied with warming pulses during a warming operation. As another example, the warming maps 400-600 may be generated through thermal imaging of the printer die 106, for instance, following a printing operation, to identify areas of lower temperature and the drop generators 116 located near the areas of lower temperature may be identified in a warming map as being the drop generators 116 that are to be supplied with warming pulses during a warming operation. In one regard, therefore, the warming map may differ for different types of printing systems, different printmodes of a printing system, etc. In addition, the warming maps for printer die 106 that are formed of different types of materials, e.g., ceramic, plastic, etc., may differ from each other.
With reference first to
Turning now to
With reference to
In other examples, the warming map may include a different distribution of the drop generators 116 located along a first column 115a of a print slot 108 as compared with the drop generators 116 located along a second column 115b of the print slot 108.
As discussed above with respect to
In another example, a first warming map may be accessed and implemented for the drop generators 116 in one of the print slots 108-114 and a second warming map be accessed and implemented for the drop generators 116 in another one of the print slots 108-114, in which the second warming map differs from the first warming map. In this example, for instance, the warming maps for the print slots 108 and 114 located near the top and bottom of the printer die 106 may have a larger number of drop generators 116 that are to receive the warming pulses than the warming maps for the print slots 110 and 112 located near the middle of the printer die 106 that are to be supplied with the warming pulses during a warming operation.
According to another example, at block 302, the warming map accessing module 210 may access a warming map from a plurality of available warming maps to which the warming map accessing module 210 may have access. For instance, the warming map accessing module 210 may have access to each of the warming maps 400-600. In this example, each of the available warming maps may identify a different non-uniform distribution of drop generators 116. By way of example, the warming map accessing module 210 may access a first warming map to be implemented during a warming operation that is performed prior to performing a printing operation and may access a second warming map to be implemented during warming operation that is performed during a printing operation. As another example, the warming map accessing module 210 may access a first warming map to be implemented for a first type of print mode and a second warming map to be implemented for a second type of print mode. As a yet further example, the warming map accessing module 210 may access a first warming map when the printing system 100 is to print graphics and to access a second warming map when the printing system 100 is to print text. As a further example, the warming map accessing module 210 may automatically switch between different warming maps in order to achieve the highest level of temperature distribution uniformity. In this example, the decision as to which warming map to implement may be based upon a running drop generator 116 firing history, data obtained by local temperature sensors, etc.
Some or all of the operations set forth in the method 300 may be contained as utilities, programs, or subprograms, in any desired computer accessible medium. In addition, the method 300 may be embodied by computer programs, which may exist in a variety of forms both active and inactive. For example, they may exist as machine readable instructions, including source code, object code, executable code or other formats. Any of the above may be embodied on a non-transitory computer readable storage medium.
Examples of non-transitory computer readable storage media include computer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes. It is therefore to be understood that any electronic device capable of executing the above-described functions may perform those functions enumerated above.
Turning now to
The computer readable medium 710 may be any suitable medium that participates in providing instructions to the processor 702 for execution. For example, the computer readable medium 710 may be non-volatile media, such as an optical or a magnetic disk; volatile media, such as memory. The computer-readable medium 710 may also store a warming map implementing machine readable instructions 714, which may perform the method 300 and may include the modules 210 and 212 of the warming map implementing apparatus 104 depicted in
Although described specifically throughout the entirety of the instant disclosure, representative examples of the present disclosure have utility over a wide range of applications, and the above discussion is not intended and should not be construed to be limiting, but is offered as an illustrative discussion of aspects of the disclosure.
What has been described and illustrated herein is an example of the disclosure along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Many variations are possible within the spirit and scope of the disclosure, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.
Number | Date | Country | |
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Parent | 15304603 | Oct 2016 | US |
Child | 15874837 | US |