Patent Publication Number: US-9427955-B2

Title: To control a printer carriage

Description:
PRIORITY 
     This application is a continuation application of commonly assigned and copending U.S. patent application Ser. No. 13/873,783, filed on Apr. 30, 2013, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Printer apparatus, such as inkjet printers, include a printer carriage on which a printhead is installed. The printer carriage is moveable bidirectionally along a scan axis and enables the printhead to provide printing fluid (such as ink) along the width of the media. The printer apparatus is arranged to move the media through the printer apparatus along a media axis and thereby enable the printhead to provide printing fluid along the length of the media. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
       Reference will now be made by way of example only to the accompanying drawings in which: 
         FIG. 1  illustrates a schematic diagram of printer apparatus according to an example; 
         FIG. 2  illustrates a plan view of printer apparatus according to an example; 
         FIG. 3  illustrates a flow diagram of a method of controlling a printer carriage according to an example; 
         FIG. 4  illustrates a plan view of printed media according to an example; 
         FIG. 5  illustrates a graph of carriage speed versus time for printing the printed media illustrated in  FIG. 4 ; 
         FIG. 6  illustrates a flow diagram of a method of controlling the movement of media according to an example; 
         FIG. 7  illustrates a plan view of printed media according to another example; 
         FIG. 8  illustrates a graph of media speed versus time for printing the printed media illustrated in  FIG. 7 ; and 
         FIG. 9  illustrates a schematic diagram of another printer apparatus according to an example. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a schematic diagram of printer apparatus  10  including a controller  12 , a first actuator  14 , a printer carriage  16 , a printhead  18 , a second actuator  20  and a heater unit  22 . The printer apparatus  10  may include a single housing for housing the controller  12 , the first actuator  14 , the printer carriage  16 , the printhead  18 , the second actuator  20  and the heater unit  22  therein. In other examples, the printer apparatus  10  may comprise separate housings for different components (for example, a first housing for the controller  12 , the first actuator  14 , the printer carriage  16 , the printhead  18  and the second actuator  20 , and a second housing the heater unit  22 ). 
     The printer apparatus  10  may be a module in some examples. As used here, ‘module’ refers to a unit or apparatus that excludes certain parts/components that would be added by an end manufacturer or a user. For example, where the printer apparatus  10  is a module, the printer apparatus  10  may only include the controller  12  (the first actuator  14 , the printer carriage  16 , the printhead  18 , the second actuator  20  and the heater unit  22  being added by an end manufacturer). 
     In overview, the printer apparatus  10  is arranged to receive media  24  (which may be a sheet or web of media), and print on the media  24  using printing fluid. The printed media  24  is then provided to the heater unit  22  which then dries the printed media  24 . The printer apparatus  10  then outputs the printed media  24  for collection by a user. 
     The implementation of the controller  12  can be in hardware alone (for example, a circuit, a processor and so on), have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware). 
     The controller  12  may be implemented using instructions that enable hardware functionality, for example, by using executable computer program instructions in a general-purpose or special-purpose processor  26  that may be stored on a computer readable storage medium  28  (disk, memory and so on) to be executed by such a processor  26 . 
     The processor  26  is configured to read from and write to the memory  28 . The processor  26  may also comprise an output interface via which data and/or commands are output by the processor  26  and an input interface via which data and/or commands are input to the processor  26 . 
     The memory  28  stores a computer program  30  comprising computer program instructions that control the operation of the printer apparatus  10  when loaded into the processor  26 . The computer program instructions  30  provide the logic and routines that enables the printer apparatus  10  to perform the methods illustrated in  FIGS. 3 and 6 . The processor  26  by reading the memory  28  is able to load and execute the computer program  30 . 
     The printer apparatus  10  may therefore comprise: at least one processor  26 ; and at least one memory  28  including computer program code  30 ; the at least one memory  28  and the computer program code  30  configured to, with the at least one processor  26 , cause the printer apparatus  10  at least to perform: controlling the printer carriage  16  to move along a first axis at a first predetermined speed when the printhead  18 , installed on the printer carriage  16 , is ejecting printing fluid in a print zone, the printer carriage  16  being moveable bidirectionally along the first axis in swaths to enable the printhead  18  to print in the print zone; and controlling the printer carriage  16  to move along the first axis at a second predetermined speed, higher than the first predetermined speed, when the printhead  18  is not ejecting printing fluid in the print zone. 
     The computer program  30  may arrive at the printer apparatus  10  via any suitable delivery mechanism  32 . The delivery mechanism  32  may be, for example, a non-transitory computer-readable storage medium, a computer program product, a memory device, a record medium such as a compact disc read-only memory (CD-ROM) or digital versatile disc (DVD) or a solid state memory, an article of manufacture that tangibly embodies the computer program  30 . The delivery mechanism  32  may be a signal configured to reliably transfer the computer program  30 . The printer apparatus  10  may propagate or transmit the computer program  30  as a computer data signal. 
     Although the memory  28  is illustrated as a single component it may be implemented as one or more separate components some or all of which may be integrated/removable and/or may provide permanent/semi-permanent/dynamic/cached storage. 
     References to ‘computer-readable storage medium’, ‘computer program product’, ‘tangibly embodied computer program’ etc. or a ‘controller’, ‘computer’, ‘processor’ etc. should be understood to encompass not only computers having different architectures such as single/multi-processor architectures and sequential (Von Neumann)/parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc. 
     As used in this application, the term ‘circuitry’ refers to all of the following: 
     (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and 
     (b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus to perform various functions) and 
     (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. 
     This definition of ‘circuitry’ applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term “circuitry” would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. 
     The first actuator  14  is configured to move the printer carriage  16  relative to the media  24 . The first actuator  14  is arranged to move the printer carriage  16  at a plurality of different speeds (that is, the first actuator  14  may move the printer carriage  16  at two or more speeds that are greater than zero kilometers per hour). The first actuator  14  may be any suitable actuator or combination of actuators and may include at least one servo motor for example. The controller  12  is arranged to control the first actuator  14  to move the printer carriage  16 . 
     The printer carriage  16  may have any suitable structure for receiving the printhead  18  and enabling the printhead  18  to be installed therein. In some examples, the printer carriage  16  is coupled to the first actuator  14  via a carriage belt (not illustrated in  FIG. 1 ). 
     The printhead  18  is installed in the printer carriage  16  and is arranged to provide printing fluid. The printhead  18  may be any suitable printhead and may be an inkjet printhead that includes a plurality of nozzles for ejecting printing fluid. The printing fluid may be any suitable ink or combination of inks and may include, for example, latex ink. The controller  12  is arranged to control the printhead  18  to provide printing fluid. 
     The second actuator  20  is configured to move the media  24  under the printer carriage  16  to enable the printhead  18  to print along the length of the media  24 . The second actuator  14  is arranged to move the media  24  at a plurality of different speeds (that is, the second actuator  20  may move the media  24  at two or more speeds that are greater than zero kilometers per hour). The second actuator  20  may be any suitable actuator or combination of actuators and may include at least one roller for moving the media  24 . The controller  12  is configured to control the second actuator  20  to move the media  24 . 
     The heater unit  22  is arranged to receive the printed media  24  and provide heat to printed media  24 . The heat from the heater unit  22  may increase the rate at which the printing fluid on the media  24  dries. Where the printing fluid includes latex ink, the heat from the heater unit  22  dries and cures the latex ink. 
       FIG. 2  illustrates a plan view of the printer apparatus  10  according to an example. In this Fig, the first actuator  14 , the second actuator  20 , the printer carriage  16 , the printhead  18 , and the media  24  are illustrated. 
     The first actuator  14  includes a servo motor  14  and a carriage belt  34 . The servo motor  14  is coupled to the printer carriage  16  via the carriage belt  34 . The first actuator  14  is arranged to move the printer carriage  16  bidirectionally in swaths along a first axis  36  (which may also be referred to as a scan axis  36 ) and therefore across the width of the media  24 . As used here, a swath of the printer carriage  16  is where the printer carriage  16  moves back and forth across the width of the media  24 . For example, a first swath of the printer carriage  16  covers a first portion of the media  24 , and a second swath of the printer carriage  16  covers a second different portion of the media  24 . 
     The second actuator  20  includes a servo motor  38  and a roller  40 . The roller  40  is arranged to receive the media  24  and the servo motor  38  is arranged to rotate the roller  40  and thereby move the media  24  along a second axis  42  (which may also be referred to as the media axis  42 ) and under the printer carriage  16 . The second axis  42  is orthogonal to the first axis  36 . In some examples, the second actuator  20  may include a plurality of servo motors  38  and rollers  40  distributed throughout the printer apparatus  10  that function to move the media  24  along the second axis  42  and through the printer apparatus  10 . 
     The movement of the printer carriage  16  and the media  24  by the first and second actuators  14 ,  20  enables the printhead  18  to eject printing fluid over a print zone  43  of the media  24 . In some examples, the print zone  43  may be equal to the width of the media  24 . In other examples, the print zone  43  may be smaller than the width of the media  24  (that is, at least one margin may be positioned adjacent the print zone  43  in which the printhead  18  does not eject printing fluid). The print zone  43  may include areas that receive printing fluid from the printhead  18  and other areas that do not receive printing fluid from the printhead  18 . Therefore, the print zone may be defined as an area in which the printhead  18  may eject printing fluid. 
       FIG. 3  illustrates a flow diagram of a method of controlling the printer carriage  16  according to an example. 
     At block  44 , the controller  12  analyses image data (which may be stored on the memory  28  for example) to determine if at least one subsequent swath to be printed includes a region in which the printhead  18  is to eject printing fluid. For example, the controller  12  may analyze the next swath in the image data, a plurality of swaths in the image data, or may analyze all of the swaths in the image data prior to performing block  46  or block  48 . 
     At block  46 , the controller  12  uses the analysis performed in block  44  to control the printer carriage  16  to move along the first axis  36  at a first predetermined speed when the printhead  18  is ejecting printing fluid in the print zone  43 . 
     At block  48 , the controller  12  uses the analysis performed in block  44  to control the printer carriage  16  to move along the first axis  36  at a second predetermined speed, higher than the first predetermined speed, when the printhead  18  is not ejecting printing fluid in the print zone  43 . 
     Blocks  46  and  48  may be performed by the controller  12  a plurality of times and in different orders depending upon the image data. For example, where a swath does not include any region that is to receive printing fluid, the controller  12  may control the printer carriage  16  to move at the second predetermined speed in that swath. By way of another example, where a swath includes a region that is to receive printing fluid, and a region that is not to receive printing fluid, the controller  12  may control the printer carriage  16  to move at the first predetermined speed over the region to receive printing fluid, and control the printer carriage  16  to move at the second predetermined speed over the region that is not to receive printing fluid. 
     In some examples, the first predetermined speed is the normal print mode speed of the printer apparatus  10  and the second predetermined speed is faster than the normal print mode speed of the printer apparatus  10 . The controller  12  may also be arranged to control the first actuator  14  to move the printer carriage  16  at a plurality of different speeds that are greater than the first predetermined speed. 
     At block  50 , the controller  12  controls the heater unit  22  to provide heat to the printing fluid on the media  24 . In some examples, the printer apparatus  10  may not include a heater unit  22  and in these examples, the method does not include block  50 . 
     In some examples, the first predetermined speed (that is, the normal, or default, print mode speed of the printer apparatus  10 ) of block  46  may not be the lowest speed of the printer carriage  16 . In these examples, the controller  12  uses the analysis performed in block  44  to control the printer carriage  16  to move along the first axis  36  at a predetermined speed that is lower than the first predetermined speed when the printhead  18  is ejecting printing fluid in the print zone  43  at a higher printing fluid density. For example, the first predetermined speed may be used when the printing fluid density is 70% of the maximum printing fluid density, and a lower predetermined speed may be used when the printing fluid density is greater than 70% of the maximum printing fluid density. This feature may be advantageous in that it may provide a faster default print mode speed. 
       FIG. 4  illustrates a plan view of printed media  24  according to an example. The media  24  includes a first region  52  that has received printing fluid and a second region  54  that has a received printing fluid. The first region  52  and the second region  54  were printed in one swath  56  of the printer carriage  16  (either in one or two passes) and are spaced apart from one another. The swaths  58 ,  60  which are before and after the swath  56  respectively do not include any regions that have received printing fluid. 
       FIG. 5  illustrates a graph  62  of carriage speed versus time for printing the swath  56  of the printed media  24  illustrated in  FIG. 4 . The graph  62  includes a horizontal axis  64  for time, a vertical axis  66  for speed, and a line  68  that represents the speed of the printer carriage  16  over time. 
     At time t 1 , the printer carriage  16  is positioned outside of the print zone  43  and the controller  12  controls the first actuator  14  to move the printer carriage  16  at the second predetermined speed V 2 . Between times t 1  and t 2 , the printer carriage  16  is accelerated to the second predetermined speed and the printer carriage  16  enters the print zone  43  at time t 2 . The printer carriage  16  moves at the second predetermined speed V 2  for a period of time and the controller  12  then controls the first actuator  14  to move the printer carriage  16  at the first predetermined speed V 1 . 
     At time t 3 , the printer carriage  16  is moving at the first predetermined speed V 1  and the controller  12  controls the printhead  18  to eject printing fluid onto the media  24  and over the first region  52 . At time t 4 , the controller  12  controls the printhead  18  to stop ejecting printing fluid and controls the first actuator  14  to move the printer carriage  16  at the second predetermined speed V 2 . 
     The printer carriage  16  moves at the second predetermined speed V 2  for a period of time and the controller  12  then controls the first actuator  14  to move the printer carriage  16  at the first predetermined speed V 1 . At time t 5 , the printer carriage  16  is moving at the first predetermined speed V 1  and the controller  12  controls the printhead  18  to eject printing fluid onto the media  24  and over the second region  54 . At time t 6 , the controller  12  controls the printhead  18  to stop ejecting printing fluid and controls the first actuator  14  to move the printer carriage  16  at the second predetermined speed V 2 . At time t 7 , the printer carriage  16  exits the print zone  43  and the controller  12  controls the first actuator  14  to stop the movement of the printer carriage  16 . 
     The velocity profile illustrated in  FIG. 5  may be repeated where the first region  52  and the second region  54  are printed in two passes of the printer carriage  16 . Where the first and second regions  52 ,  54  are printed in a single pass of the printer carriage  16 , the controller  12  may control the first actuator  14  to return the printer carriage  16  back to the starting position (that is, the position of the printer carriage  16  at time t 1 ) at the second predetermined speed. 
     The printer apparatus  10  is advantageous in that where the printhead  18  is not ejecting printing fluid, the controller  12  controls the first actuator  14  to move the printer carriage  16  at a greater speed than when the printhead is ejecting printing fluid. This may result in the printer carriage  16  requiring less time to complete a swath of printing and may consequently increase the throughput of media through the printer apparatus  10 . Therefore, the printer apparatus  10  may have increase productivity, and due to the greater throughput of media, provide a reduced cost for printing. 
       FIG. 6  illustrates a flow diagram of a method of controlling the movement of media according to an example. At block  70 , the controller  12  analyses image data (stored on the memory  28  for example) to determine if at least one subsequent swath includes a region in which the printhead is to eject printing fluid. 
     At block  72 , the controller  12  uses the analysis performed in block  70  to control the media  24  to move along the second axis  42  at a third predetermined speed when the printhead is ejecting printing fluid in a subsequent swath. 
     At block  74 , the controller  12  uses the analysis performed in block  70  to control the media  24  to move along the second axis  42  at a fourth predetermined speed, higher than the third predetermined speed, when the printhead is not ejecting printing fluid in a subsequent swath. 
     Blocks  72  and  74  may be performed by the controller  12  a plurality of times and in different orders depending upon the image data. In some examples, the third predetermined speed may be the normal print mode media axis speed of the printer apparatus  10  and the fourth predetermined speed is faster than the normal print mode media axis speed of the printer apparatus  10 . The controller  12  may also be arranged to control the second actuator  20  to move the media  24  at a plurality of different speeds that are greater than the third predetermined speed. 
     In some examples, the controller  12  may control the media  24  to move along the second axis  42  at the fourth predetermined speed when the printhead  18  is not ejecting printing fluid in a plurality of subsequent swaths which is greater than a threshold number of swaths. If the number of swaths is less than the threshold number, the controller  12  controls the media  24  to move along the second axis  42  at the third predetermined speed. 
       FIG. 7  illustrates a plan view of printed media  24  according to an example. The media  24  includes a region  76  that has received printing fluid and was printed in two swaths  78 ,  80  of the printer carriage  16  (either in one or two passes of the printer carriage). The swaths  82 ,  84  which are before and after the swaths  78 ,  80  respectively do not include any regions that have received printing fluid. 
       FIG. 8  illustrates a graph  86  of media speed versus time for printing the media  24  illustrated in  FIG. 7 . The graph  86  includes a horizontal axis  88  for time, a vertical axis  90  for speed, and a line  92  that represents the speed of the media  24  over time. 
     At time t 1 , the controller  12  controls the movement of the media  24  to move at the fourth predetermined speed since the swath  82  does not include a region that receives printing fluid from the printhead  18 . At time t 2 , the controller  12  controls the movement of the media  24  so that the media  24  is brought to a stop at time t 3 . Between times t 1  and t 3 , the printer carriage  16  remains stationary. 
     Between times t 3  and t 4 , the controller  12  controls the printer carriage  16  to move along the first axis  36  in swath  78  to enable the printhead  18  to eject printing fluid within region  76  (the media remaining stationary). The printer carriage  16  is moved at varying speeds in accordance with the preceding paragraphs and as illustrated in  FIG. 3 . At time t 4 , the controller  12  controls the movement of the media  24  to move at the third predetermined speed V 3  and then controls the movement of the media  24  so that the media  24  is brought to a stop at time t 5 . 
     Between times t 5  and t 6 , the controller  12  controls the printer carriage  16  to move along the first axis  36  in swath  80  to enable the printhead  18  to eject printing fluid within region  76  (the media remaining stationary). The printer carriage  16  is moved at varying speeds in accordance with the preceding paragraphs and as illustrated in  FIG. 3 . At time t 6 , the controller  12  controls the movement of the media  24  to move at the fourth predetermined speed V 4  since the swath  84  does not include a region that receives printing fluid from the printhead  18 . 
     The printer apparatus  10  is advantageous in that where the printhead  18  is not ejecting printing fluid in a subsequent swath, the controller  12  controls the second actuator  20  to move the media  24  at a greater speed than when the printhead is ejecting printing fluid in a subsequent swath. This may result in an increase in the throughput of media through the printer apparatus  10 . 
     The blocks illustrated in  FIGS. 3 and 6  may represent steps in a method and/or sections of code in the computer program  30 . The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some blocks to be omitted. 
     Although examples of the present invention have been described in the preceding paragraphs, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. 
     For example,  FIG. 9  illustrates a schematic diagram of another printer apparatus  101  according to an example. The printer apparatus  101  is similar to the printer apparatus  10  and where the features are similar, the same reference numerals are used. 
     The printer apparatus  101  differs from the printer apparatus  10  in that the controller  12  includes first circuitry  94  and second circuitry  96 . The first circuitry  94  is arranged to block  44  illustrated in  FIG. 3  and block  70  illustrated in  FIG. 6 . The second circuitry  96  is arranged to perform blocks  46 ,  48  in  FIG. 3  and blocks  72  and  74  illustrated in  FIG. 6 . 
     In some examples, the first circuitry  94  is an application specific integrated circuit (ASIC) and is arranged to determine if a swath includes a region in which the printhead is to eject printing fluid by performing non-zero-row-logging. 
     Features described in the preceding description may be used in combinations other than the combinations explicitly described. 
     Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. 
     Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not. 
     Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.