Patent Publication Number: US-11027550-B2

Title: Spitting offsets for printheads

Description:
BACKGROUND 
     Printing devices are often used to present information. In particular, printing devices may be used to generate output that may be easily handled and viewed or read by users. Accordingly, the generation of output from printing devices from electronic form is used for the presentation and handling of information. Some printing devices use print fluids to generate output. In such printing devices, the print fluids are generally applied to a medium. Print fluids may be applied to a medium via a printhead having a plurality of nozzles or dies that may eject the print fluid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made, by way of example only, to the accompanying drawings in which: 
         FIG. 1  is a schematic representation of an example apparatus to reduce textile use during health spitting procedures of a printhead; 
         FIG. 2A  is a top view of the example apparatus of  FIG. 1  with the textile in a first position; 
         FIG. 2B  is a top view of the example apparatus of  FIG. 1  with the textile in a second position; 
         FIG. 3A  is a view of the textile after the first health spitting procedure from the first nozzle; 
         FIG. 3B  is a view of the textile after the second health spitting procedure from the second nozzle; 
         FIG. 4  is a schematic representation of another example apparatus to reduce textile use during health spitting procedures of a printhead; 
         FIG. 5A  is a schematic representation of another example apparatus to reduce textile use during health spitting procedures of a printhead; 
         FIG. 5B  is a bottom view of the printhead of the apparatus of  FIG. 5A ; 
         FIG. 6  is a view of the textile after the health spitting procedures carried out by the apparatus of  FIG. 5A ; 
         FIG. 7  is a schematic representation of the example controller of the apparatus of  FIG. 5A ; and 
         FIG. 8  is a flowchart of an example of a method of reducing textile use during health spitting procedures of a printhead. 
     
    
    
     DETAILED DESCRIPTION 
     Some printing devices use fluids to generate output. For example, printing devices may generate documents, images, or three-dimensional objects. In such printing devices, fluid delivery systems are generally used to deliver a liquid from one part of the printing device, such as a reservoir to a printhead where the fluid is subsequently ejected through a nozzle onto a media, such as paper, to generate an image. Over time, the health of the nozzle degrades. For example, the nozzle health may degrade and become less responsive or completely inoperable due to mechanical degradation. In other examples, the nozzle health may degrade due to a build-up of deposits around the nozzle, such as dried print fluid, dirt, dust particles, and/or fibers released from a print media. 
     As deposits build up on a nozzle, a cleaning procedure may be used to clean the nozzle to restore it to good health. In order to reduce nozzle clogs and to restore nozzles to a healthy state for subsequent printing operations, nozzles may be periodically exercised by ejecting a number of ink drops. This may be carried out upon detection of an unhealthy nozzle or at fixed intervals of time. The process of exercising the nozzle in such a manner may be commonly referred to as “health spitting” or simply as “spitting.” 
     In some examples, the health spitting occurs over a waste material, such as a textile. The waste material may also be used to physically contact the nozzle to remove any buildup of contaminants on the nozzle. Accordingly, the waste material, such as a textile, is to be cleaned to reduce the risk of further contamination. 
     In the examples described below, an apparatus is provided that may be used to keep the nozzles clean and relatively free from contaminants. In particular, the apparatus provides a manner by which the health spitting process may be carried out on a reduced amount of textile or other waste material. Accordingly, the apparatus may be used to reduce costs as well as the consumption of single use components. 
     As used herein, any usage of terms that suggest an absolute orientation (e.g. “top”, “bottom”, “vertical”, “horizontal”, etc.) are for illustrative convenience and refer to the orientation shown in a particular figure. However, such terms are not to be construed in a limiting sense as it is contemplated that various components will, in practice, be utilized in orientations that are the same as, or different than those described or shown 
     Referring to  FIG. 1 , an apparatus  10  to reduce textile use during health spitting procedures of a printhead  15  is generally shown. In the present example, the apparatus  10  may be part of a printing device to maintain and/or improve the health of nozzles on the printhead  15 . Accordingly, the printing device may include additional components for delivering print fluid to print media as well as for positioning the print media within the printing device. The apparatus  10  may include additional components, such as various controllers, and additional interfaces or displays to interact with a user or administrator. In other examples, the apparatus  10  may be integrated with the control systems of the printing device such that interfaces and controllers are managed by the printing device or another computing device. Furthermore, in some examples, the apparatus  10  may be used during the printing process to clean the nozzles between print jobs or during the print job. In other examples, the apparatus  10  may be used upon user request. In the present example, the apparatus  10  includes a printhead  15 , nozzles  20  and  25 , and a textile  30 . 
     The printhead  15  is to dispense print fluid in general. For example, the printhead  15  may dispense print fluid onto media to generate an output image. The manner by which the printhead  15  dispenses the print fluid is not limited. For example, the printhead  15  may eject a plurality if drops of print fluid. In the present example, the printhead  15  may eject drops of print fluid under pressure such that the drops travel along a drop path from the printhead  15  through the air to a target, such as to a print media or to the textile  30  as discussed in greater detail below. The source of the print fluid provided to the printhead  15  is also not limited. For example, the printhead  15  may receive print fluid from a tank, reservoir, or other print fluid source. The printhead  15  may use a thermal ink jet or a piezo ink jet mechanism to push the print fluid from the print fluid source to the target. In other examples. the printhead  15  may include a motor and/or vacuum to draw the print fluid via a fluid line. In further examples, the printhead  15  may use capillary action to draw the print fluid or the printhead  15  may include a tank such that the print fluid is delivered to the printhead  15  by gravity. In some examples, the printhead  15  may include multiple sources of print fluid where each source of print fluid may provide a different print fluid. For example, the printing device may have separate tanks of print fluid for different colors, such as black, cyan, magenta, and yellow. The print fluid from each source may be directed to different nozzles on the printhead  15 . Accordingly, during a printing operation, the printhead  15  may dispense a mixture of different colors to deposit on the media depending on the output image. 
     In some examples, the printhead  15  may also include various control components such as a controller or microprocessor. The controller or microprocessor may receive electrical signals corresponding to a print job. The printhead  15  may then coordinate the nozzles  20  and  25  to dispense the print fluid onto the textile  30  during the health spitting and to dispense the print fluid onto the print media to generate an image or document. As discussed above, the control components may also be used to control the apparatus  10  and/or other systems for maintaining the health of the nozzles  20  and  25  on the printhead  15  as well as detecting and diagnosing the health of the nozzles  20  and  25  with a diagnosis system, such as an optical drop detection system (not shown). 
     The nozzle  20  is disposed on the printhead  15  and is to eject a plurality of drops of print fluid onto the textile during a health spitting process to remove contaminants from the nozzle  20 . The manner by which the nozzle  20  carries out the health spitting process is not limited. In the present example, the nozzle  20  may eject a plurality of drops of print fluid under high pressure such that the plurality drops push any contaminants lodged near the tip of the nozzle  20  free. In other examples, the nozzle  20  may also receive mechanical assistance to remove contaminants, such as contact from the textile  30  or a brush (not shown). 
     The nozzle  25  is also disposed on the printhead  15  and is to eject a plurality of drops of print fluid onto the textile during a health spitting process to remove contaminants from the nozzle  25 . In the present example, the nozzle  25  is to be offset from the nozzle  20  by an offset distance of x as shown in  FIG. 2A . The offset distance is not particularly limited. In the present example, the offset distance may be about 10 mm. In other examples, the offset distance may be smaller, such as about 5 mm, or larger, such as about 15 mm. It is to be appreciated that the offset distance is to be measured along a direction of travel of the textile  30 , which is the same direction of travel of the print media relative to the printhead  15 . 
     The manner by which the nozzle  25  carries out the health spitting process is not limited and may include the methods discussed above in connection with the nozzle  25 . In the present example, the nozzle  25  may eject a plurality of drops of print fluid under high pressure such that the plurality drops push any contaminants lodged near the tip of the nozzle  25  free. In other examples, the nozzle  25  may also receive mechanical assistance to remove contaminants, such as contact from the textile  30  or a brush (not shown). 
     The textile  30  is to receive the plurality of drops of print fluid from the nozzle  20  and the nozzle  25 . In particular, the textile  30  is to absorb the print fluid without allowing the print fluid to run along the surface of the textile  30  or to bounce off the textile  30  to further contaminate the printhead  15  or other parts of the printing device, such as the print media (not shown), which may be adjacent to the textile  30 . The material from which the textile  30  may be constructed is not particularly limited. For example, the textile  30  may be cotton, paper, or other material capable of absorbing print fluid. 
     Referring to  FIG. 2A , the textile  30  may also be moved relative to the printhead  15  by the offset distance x along the direction of travel indicated by the arrow A to the position shown in  FIG. 2B . In particular, the textile  30  may be moved between the ejection of the plurality of drops from the nozzle  20  and the ejection of the plurality of drops from the nozzle  25 . It is to be appreciated that the health spitting procedure is to be carried out by the nozzle  20  and the nozzle  25  in sequential order; however, the specific order may be changed. In the present example, the nozzle  20  carries out the health spitting process in the position shown in  FIG. 2A  to generate a spot  50  as shown in  FIG. 3A . After the health spitting process for the nozzle  20  is completed, the textile  30  is moved by the offset distance to the position shown in  FIG. 2B  in which the nozzle  25  carries out the health spitting process to generate a spot  55  as shown in  FIG. 3B . The spot  50  and the spot  55  form a spit pattern. The size of the spot  50  and the spot  55  is not particularly limited and is dependent on the configuration of the printhead  15  as well as the distance the textile  30  is from the printhead  15  and the amount of print fluid ejected during the health spitting process. For example, the width of the spot  50  and the spot  55  may be at least about 1 mm wide in some examples. In other examples, the width of the spot  50  and the spot  55  may be at least about 4 mm wide. Further examples may have non-uniform spot sizes. 
     Referring to  FIG. 3B , in the present example, the spit pattern is formed in a substantially straight line perpendicular to the travel direction of the textile  30  and the print media (not shown). It is to be understood that by forming the spit pattern into a substantially straight line may serve to reduce the amount of textile  30  used during the health spitting procedure for the nozzle  20  and the nozzle  25 . In particular, since the width of the textile  30  used in the health spitting procedure of the nozzle  20  and the nozzle  25  is limited to the width of the spot  50  and the spot  55 , the subsequent health spitting procedure may be carried out adjacent to the line formed by the spot  50  and the spot  55 . Continuing with the example above where the offset distance is about 10 mm and the width of the spot  50  and the spot  55  are about 1 mm each, the apparatus  10  reduces the amount of textile  30  used by up to about 90 percent compared with a process where the nozzle  20  and the nozzle  25  carry out the health spitting simultaneously or without any movement of the textile  30  between their respective health spitting procedures. 
     The manner by which the textile  30  is moved relative to the printhead  15  is not particularly limited. For example, the textile  30  may be connected to rollers to move the textile  30 . In other examples, the textile  30  may be affixed to a moveable substrate. In further examples, the textile  30  may also be stationary and the printhead  15  may be moved instead. 
     Referring to  FIG. 4 , another apparatus  10   a  to reduce textile use during health spitting procedures of a printhead  15   a  is generally shown. Like components of the apparatus  10   a  bear like reference to their counterparts in the apparatus  10 , except followed by the suffix “a”. In the present example, the apparatus  10   a  includes a printhead  15   a , nozzles  20   a  and  25   a , a textile  30   a , a textile dispenser  35   a , and a textile collector  40   a  to collect used textile  30   a.    
     In the present example, the textile dispenser  35   a  is to dispense the textile  30   a . The textile dispenser  35   a  is not particularly limited. For example, the textile dispenser  35   a  may include a roll of textile  30   a  that is pulled out to advance the textile  30   a  after each health spitting procedure of the nozzle  20   a  and the nozzle  25   a . The textile dispenser  35   a  may also take another form in other examples, such as accordion-folded textile  30   a  in a box. 
     The textile collector  40   a  is to collect used textile  30   a  after it has received print fluid from the nozzle  20   a  and the nozzle  25   a . The textile collector  40   a  is not particularly limited and may include a roll similar to the textile dispenser  35   a . In this example, the textile collector  40   a  may receive the textile  30   a  from the textile dispenser  35   a  after the textile  30   a  receives print fluid from the health spitting process. A motor (not shown) may be optionally connected to the textile collector  40   a  to provide rotation to pull the textile  30   a  to provide motion. It is to be appreciated that this may also cause the textile dispenser  35   a  to dispense additional textile  30   a  as it is collected after use. 
     In summary, the printhead  15   a  may be used in operation to dispense print fluid. For example, the printhead  15   a  may dispense the fluid onto a print media to generate a document or image. In another example, the printhead  15   a  may dispense print fluid to generate an object during a three-dimensional printing process. As the nozzle  20   a  and the nozzle  25   a  of the printhead  15   a  are used, contaminants may build up to affect print quality. At some point, a trigger event occurs that causes the printhead  15   a  to carry out a health spitting procedure to clean the nozzle  20   a  and the nozzle  25   a  to remove contaminants. In the present example, the printhead  15   a  may then be moved over the textile  30   a  as shown in  FIG. 4 . The health spitting procedure is carried out as described above where the textile  30   a  is moved between the health spitting of the nozzle  20   a  such that the health spitting of the nozzle  25   a  is to be carried out along a straight line. The manner by which the textile  30   a  moves is not limited. In this example, the textile collector  40   a  may be used to pull the textile to form the first position to receive print fluid from the nozzle  20   a  to the second position to receive print fluid from the nozzle  25   a . In some examples, the textile dispenser  35   a  may also be equipped with a motor to pull the textile  30   a  in the reverse direction. This feature may be used to reposition the textile  30   a  such that the spit pattern may be further packed closer together with a subsequent spit pattern. 
     Referring to  FIG. 5A , another apparatus  10   b  to reduce textile use during health spitting procedures of a printhead  15   b  is generally shown. Like components of the apparatus  10   b  bear like reference to their counterparts in the apparatus  10 , except followed by the suffix “b”. In the present example, the apparatus  10   b  includes a printhead  15   b , printhead dies  20   b - 1 ,  20   b - 2 ,  20   b - 3 ,  25   b - 1 , and  25   b - 2  (as shown in  FIG. 5B ; generically, these printhead dies are referred to herein as “printhead die  20   b ” or “printhead die  25   b ”, and collectively they are referred to as “printhead dies  20   b ” or “printhead dies  25   b , this nomenclature is used elsewhere in this description), a textile  30   b , and a controller. 
     Referring to  FIG. 5B , the apparatus  10   b  includes a plurality of printhead dies  20   b  disposed on the printhead  15   b  and is to eject print fluid during a health spitting process to remove contaminants from the printhead dies  20   b . In particular, the printhead dies  20   b  are disposed along a line that is perpendicular to a direction which media is to move through a printing device. The manner by which the printhead dies  20   b  eject print fluid is not particularly limited. For example, each printhead die  20   b  may have a nozzle or orifice from which uses a thermal ink jet or a piezo ink jet mechanism to push the print fluid therethrough. 
     The printhead dies  25   b  are also disposed on the printhead  15   b  and are to eject print fluid onto the textile  30   b  during a health spitting process to remove contaminants from the printhead dies  25   b . In the present example, the printhead dies  25   b  are disposed along a line parallel to the line of printhead dies  20   b  but offset by an offset distance. The offset distance is not particularly limited. In the present example, the offset distance may be about 10 mm. In other examples, the offset distance may be smaller, such as about 5 mm, or larger, such as about 15 mm. It is to be appreciated that the offset distance is to be measured along a direction of travel of the textile  30   a , which is the same direction of travel of the print media relative to the printhead  15   a.    
     In the present example, contaminants are removed from the printhead dies  20   b  and the printhead dies  25   b  by ejecting a plurality of drops of print fluid under high pressure such that the plurality drops push any contaminants on the printhead dies  20   b  and the printhead dies  25   b  free. In other examples, the printhead dies  20   b  and the printhead dies  25   b  may also receive mechanical assistance to remove contaminants, such as contact from the textile  30   b  or a brush (not shown). 
     Referring to  FIG. 6 , in the present example, the spit pattern from the apparatus  10   b  is formed in a substantially straight line perpendicular to the travel direction of the textile  30   b  and the print media (not shown). In the present example, the spit pattern includes spots  50   b - 1 ,  50   b - 2 ,  50   b - 3 ,  55   b - 1 , and  55   b - 2 . It is to be understood that by forming the spit pattern into a substantially straight line may serve to reduce the amount of textile  30   a  used during the health spitting procedure for the printhead dies  20   b  and the printhead dies  25   b . In particular, since the width of the textile  30   a  used in the health spitting procedure of the printhead dies  20   b  and the printhead dies  25   b  is limited to the width of the spots  50   b  and the spots  55   b , the subsequent health spitting procedure may be carried out adjacent to the line formed by the spots  50   b  and the spots  55   b . For example, if it were to be assumed that that the offset distance is about 10 mm and the width of the spots  50   b  and the spots  55   b  are about 4 mm each, the apparatus  10   b  reduces the amount of textile  30   b  used by up to about 60 percent compared with a process where the printhead dies  20   b  and the printhead dies  25   b  carry out the health spitting simultaneously or without any movement of the textile  30  between their respective health spitting procedures. 
     Referring to  FIG. 7 , the controller  100  is shown in more detail. In the present example, the controller  100  is in communication with the printhead  15   b  as well as control the movement of the textile  30   b . In particular, the controller  100  may be in communication valves to control print fluid flow as well as motors to move the printhead  15   b  and the textile  30   b  in accordance with the present example. The controller  100  may include a communications interface  105 , a memory storage unit  110 , printhead controller  115 , and a textile controller  120 . 
     The communications interface  105  is to communicate with an external device to send and receive commands or other data. In the present example, the external device may be the printing device or another device to monitor the health of the printhead dies  20   b  and/or the printhead dies  25   b . In other examples, the communications interface  105  may communicate with a server to provide health data to the server, such as in examples where the printing device is managed remotely. The manner by which the communications interface  105  sends and receives data is not limited and may include sending and receiving an electrical signal via a wired connection. For example, the communications interface  105  may be connected to the printing device in examples where the apparatus  10   b  is part of the printing device, such as part of an onboard maintenance system. In other examples, the communications interface  105  may send and receive wireless signals such as via a Bluetooth connection, radio signals or infrared signals from the scanning device. In further examples, the communications interface  105  may be a network interface for communicating over a local area network or the Internet where the communications interface  105  may communicate with a remote server. 
     The memory storage unit  110  may include a non-transitory machine-readable storage medium that may be any electronic, magnetic, optical, or other physical storage device. In the present example, the memory storage unit  110  may store an operating system that is executable to provide general functionality to the apparatus  10   a , for example, to support various applications. Examples of operating systems include Windows™, macOS™, iOS™, Android™, Linux™, and Unix™. The memory storage unit  110  may additionally store instructions executable by the printhead controller  115  to operate the printhead  15   b , as well as the textile controller  120  to coordinate movement of the textile relative to the printhead  15   b.    
     In the present example, the memory storage unit  110  may also maintain a database to store a maintenance history the printhead dies  20   b  and the printhead dies  25   b . For example, a log of the last health spit procedure carried out on each printhead die  20   b  and each printhead die  25   b.    
     The printhead controller  115  is to control the printhead  15   a . In particular, the printhead controller  115  may be to direct the printhead dies  20   b  and the printhead dies  25   b  to carry out a healthy spitting procedure by ejecting print fluid. The printhead controller  115  may also be used to move the printhead  15   b  within the printing device. For example, the printhead controller  115  may be used to position the printhead  15   b  above the textile  30   b  as well as to operate the printhead during normal printing operations. 
     The printhead controller  115  is to control the printhead  15   a . In particular, the printhead controller  115  may be to direct the printhead dies  20   b  and the printhead dies  25   b  to carry out a healthy spitting procedure by ejecting print fluid. The printhead controller  115  may also be used to move the printhead  15   b  within the printing device. For example, the printhead controller  115  may be used to position the printhead  15   b  above the textile  30   b . In other examples, the printhead controller  115  may be the same controller used to control the printhead during normal printing operations. 
     Referring to  FIG. 8 , a flowchart of a method of reducing textile use during health spitting procedures is shown at  200 . In order to assist in the explanation of method  200 , it will be assumed that method  200  may be performed with the apparatus  10 . Indeed, the method  200  may be one way in which apparatus  10  is used and the following discussion of method  200  may lead to a further understanding of the apparatus  10  along with its various components. 
     Referring to block  210 , the nozzle  20  may be used to eject a plurality of drops onto the textile  30 . The plurality of drops may be ejected as part of a health spitting process to clean the nozzle  20 . In some examples, the nozzle  20  may be further cleaned after the ejection of the drops of print fluid using a mechanical process such as contacting the textile  30  to the nozzle  20  to effectively wipe the nozzle  20  clean of additional residue. 
     Block  220  comprises moving the textile  30  by an offset distance. In the present example, the offset distance is the same as the distance that the nozzle  20  and the nozzle  25  are offset in the direction of travel as shown as the value x in  FIG. 2A . It is to be appreciated that by moving the textile  30  by the offset distance, the nozzle  25  is to be positioned to eject droplets along the same line that the nozzle  20  deposited the ejected drops. The manner by which the textile  30  is moved is not particularly limited. For example, the textile  30  may be moved by having a motor attached to a dispenser roll and a collector roll such that the textile  30  may be moved in one dimension to expose clean portions and to eventually collect used portions of the textile  30 . 
     Referring to block  230 , the nozzle  25  may be used to eject a plurality of drops onto the textile  30  after the movement in block  220 . The plurality of drops may be ejected as part of a health spitting process to clean the nozzle  25  similar to the process for the nozzle  20  in block  210 . In some examples, the nozzle  25  may be further cleaned after the ejection of the drops of print fluid using a mechanical process such as contacting the textile  30  to the nozzle  25  to effectively wipe the nozzle  25  clean of additional residue. 
     It should be recognized that features and aspects of the various examples provided above may be combined into further examples that also fall within the scope of the present disclosure.