Patent Publication Number: US-2023145295-A1

Title: Vacuum conveyor system for inkjet printing with adjustment to the covered area

Description:
FIELD OF THE INVENTION 
     This description relates generally to printing systems and specifically to a vacuum conveyor system for inkjet printing with adjustment to the covered area. 
     BACKGROUND 
     Inkjet printing systems are used for non-contact ink deposition. Printing systems can sometimes use vacuum conveyor mechanisms to convey a substrate along the ink deposition stage. However, the adjustment capabilities of traditional vacuum conveyor active area adjustment systems is compromised when trying to combine a method to adjust to the substrate width and a method to adapt to the machine loading/unloading conditions. As a result, the effectivity of conventional methods is sometimes limited. 
     SUMMARY 
     Apparatus, methods, and systems for a vacuum conveyor for inkjet printing with adjustment to the covered area are disclosed. In some embodiments, a system includes a vacuum table including a vacuum chamber configured to secure a substrate for inkjet printing of the substrate. A substrate transportation system is operably coupled to the vacuum table and runs across a length of the vacuum table from a first side of the vacuum table to a second side of the vacuum table. The substrate transportation system is configured to convey the substrate from the first side to the second side for the inkjet printing. Multiple first actuators are operably coupled to the first side and located within the vacuum table. The multiple first actuators are configured to expand and retract across the length of the vacuum table from the first side to the second side to decrease the suction width and a suction length of the area of suction provided by the vacuum chamber in accordance with a substrate width and the length of the substrate transportation system covered by the substrate. 
     Multiple second actuators are operably coupled to the second side and located within the vacuum table. The multiple second actuators are configured to expand and retract along the length of the vacuum table from the first side to the second side to increase the suction length of the area of the suction in accordance with the length covered by the substrate contacting the substrate transportation system. A controller is coupled to the multiple first actuators and the multiple second actuators and configured to select one or more actuators of the multiple first actuators. The one or more actuators are caused to expand across the length of the vacuum table in accordance with the substrate width and the length of the vacuum table covered by the substrate. The multiple second actuators are caused to retract along the length of the vacuum table in accordance with the length covered by the substrate. 
     These and other aspects, features, and implementations can be expressed as methods, apparatus, systems, components, program products, means or steps for performing a function, and in other ways. 
     These and other aspects, features, and implementations will become apparent from the following descriptions, including the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a perspective view of a printing system, in accordance with one or more embodiments. 
         FIG.  2    illustrates a side view of a printing system, including a printer head and a light source, in accordance with one or more embodiments. 
         FIG.  3    illustrates a planar view of components of a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. 
         FIG.  4    is a cross-sectional view of a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. 
         FIGS.  5 A,  5 B,  5 C, and  5 D  illustrate planar views of a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. 
         FIG.  6    is a flow diagram illustrating a process for a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. 
         FIG.  7    is a block diagram illustrating a computer system to control a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present embodiments. It will be apparent, however, that the present embodiments may be practiced without these specific details. 
     This document presents systems, methods, and apparatus for a vacuum conveyor for inkjet printing with adjustment to the covered area. The embodiments disclosed herein present methods for expanding, by a controller of a vacuum conveyor system, first one or more actuators of multiple first actuators of the vacuum conveyor system to decrease the suction width of the area of suction provided by the vacuum conveyor system in accordance with the width of a substrate being inkjet printed using the vacuum conveyor system. A second one or more actuators of the multiple first actuators are retracted while the multiple second actuators are expanded. The controller retracts multiple second actuators of the vacuum conveyor system to increase the suction length of the area of suction as the substrate transportation system of the vacuum conveyor system moves the substrate along the vacuum conveyor system for inkjet printing of the substrate. This situation is maintained as long as the number of substrates on the conveyor is a maximum number. As the machine is unloaded of substrates, the controller expands the multiple retracted first actuators of the vacuum conveyor system to decrease the suction length as the substrate moves along the vacuum conveyor system. 
     The advantages and benefits of the vacuum conveyor system for inkjet printing with adjustment to the covered area using the embodiments described herein include improved integration of combined adjustment systems to substrate width and machine loading/unloading conditions. Further, the pneumatic expanding actuators used in some embodiments provide increased robustness over traditional methods. The embodiments disclosed herein provide the capability to handle a single substrate during the machine loading/unloading scenarios. 
       FIG.  1    illustrates a perspective view of a printing system  100 , in accordance with one or more embodiments. The printing system  100  includes a printer head  106 , at least one light source  112 , and a substrate transportation system  102 . Embodiments may include various combinations of these and other components, e.g., a dryer. For example, the light source  112  may be present in some embodiments, but not in others. As another example, a dryer may be included if an image  110  will not be quickly transferred to a substrate. The substrate transportation system  102  can include a belt, actuators, pulleys, etc., to move the substrate. While the printing system  100  of  FIG.  1    can include a transfer belt, other means for conveying and/or retaining a substrate or transfer material  104  can also be used, such as a rotating platform or stationary bed. 
     The printer head  106  is configured to deposit ink onto a substrate or the transfer material  104  in the form of an image  110 . An example substrate  532  is illustrated and described in more detail with reference to  FIG.  5 B . The transfer material  104 , which may also be referred to as a former material, is flexible, which allows the image  110  to be transferred to complex-shaped substrates. For example, the transfer material  104  may be a rubber former, a thermoformable material, etc. In some embodiments, the printer head  106  is an inkjet printer head that jets ink onto the substrate or the transfer material  104  using, for example, piezoelectric nozzles. Thermal printer heads are generally avoided in an effort to avoid premature sublimation of the ink. In some embodiments, the ink is a solid energy, e.g., UV curable ink. However, other inks may also be used, such as water-based energy curable inks or solvent-based energy curable inks. The ink can be deposited in different forms, such as ink droplets and colored polyester ribbons. 
     In some embodiments, one or more light sources  112  cure some or all of the ink deposited onto the substrate or the transfer material  104  by emitting UV radiation. The light source(s)  112  may be, for example, a UV fluorescent bulb, a UV light emitting diode (LED), a low-pressure, e.g., mercury (Hg) bulb, or an excited dimer (excimer) lamp and/or laser. Various combinations of these light sources could be used. For example, a printing system  100  may include a low-pressure Hg lamp and a UV LED. As discussed in more detail with reference to  FIG.  2   , the light source  112  may be configured to emit UV radiation of a particular subtype. 
     The printer head  106  and light source  112  are illustrated as being directly adjacent to one another, i.e., neighboring without any intervening components. However, additional components that assist in printing, curing, etc., may also be present. For example, multiple distinct light sources  112  may be positioned behind the printer head  106 .  FIG.  1    illustrates one possible order in which components may be arranged in order to print an image  110  onto the substrate or the transfer material  104 . Other embodiments are considered in which additional components are placed before, between, or after the illustrated components, etc. 
     In some embodiments, one or more of the aforementioned components are housed within one or more carriages. For example, the printer head  106  can be housed within a printing carriage  108 , the light source  112  can be housed within a curing carriage  114 , etc. In addition to protecting the components from damage, the carriages may also serve other benefits. For example, the curing carriage  114  can limit what portion(s) of the transfer material  104  and image  110  are exposed during the curing process. The printing system  100  may include pulleys, motors, rails, and/or any combination of mechanical or electrical technologies that enable the carriages to travel along the substrate transportation system (e.g., the transfer belt  102 ), i.e., with respect to the substrate or the transfer material  104 . The transfer belt  102  is affixed to a vacuum table  120  and moves over a vacuum platen  122  that is on top of the vacuum table  120 . The vacuum table and moves over a vacuum platen are illustrated and described in more detail with reference to  FIG.  4   . In alternative embodiments, the carriages can be fixedly attached to a rail or base of the printing system  100 . In these embodiments, the transfer material  104  can be moved in relation to the printer head  106 , light source  112 , etc., such that ink can be deposited onto the transfer material  104 . 
     In various embodiments, some or all of the components are controlled by a computer system  116 . The computer system  116  is the same as or similar to the computer system  700  illustrated and described in more detail with reference to  FIG.  5   . The computer system  116  can allow a user to input printing instructions and information, modify print settings, e.g., by changing cure settings, alter the printing process, etc. 
       FIG.  2    illustrates a side view of a printing system  200 , including a printer head  202  and a light source  204 , in accordance with one or more embodiments. While a single-pass configuration is illustrated by  FIG.  2   , other embodiments may employ multi-pass, i.e., scan, configurations. Similarly, embodiments can be modified for various printers, e.g., flatbed printer, drum printer, or lane printer. For example, a flatbed printer may include a stable bed and a traversing printer head, a stable printer head and a traversing bed, etc. A substrate transportation system is affixed to a vacuum table  120  and moves over a vacuum platen  122  that is on top of the vacuum table  120 . The vacuum table and vacuum platen are illustrated and described in more detail with reference to  FIG.  4   . 
     The printer head  202  can include distinct ink/color drums, e.g., cyan, magenta, yellow, and black (CMYK), or colored polyester ribbons that are deposited onto the surface of a transfer material  206 . Path A represents the media feed direction, e.g., the direction in which the substrate or the transfer material  206  travels during the printing process. Path D represents the distance between the printer head  202  and the surface of the transfer material  206 . 
     As described above, both direct and indirect printing have conventionally been carried out only on flat surfaces. The printing systems and methods described herein, however, allow images to be printed on complex-shaped, i.e., non-planar, surfaces by depositing ink directly onto a substrate or a transfer material  206  and then transferring the ink to a substrate. When printing directly onto a surface, print quality relies on accuracy of ink drop placement. Therefore, maintaining a constant or nearly constant distance between the printer head  202  and the flat surface of the transfer material  206  is necessary. Airflow, velocity variability, etc., can affect drop placement even when the change in distance is small, e.g., a few millimeters. 
     In some embodiments, a light source  204  cures some or all of the ink  208  deposited onto the substrate or the transfer material  206  by the printer head  202 . The light source  204  may be configured to emit wavelengths of UV electromagnetic radiation of subtype V (UVV), subtype A (UVA), subtype B (UVB), subtype C (UVC), or any combination thereof. Generally, UVV wavelengths are those wavelengths measured between 395 nanometers (nm) and 445 nm, UVA wavelengths measure between 315 nm and 395 nm, UVB wavelengths measure between 280 nm and 315 nm, and UVC wavelengths measure between 100 nm and 280 nm. However, one skilled in the art will recognize these ranges are somewhat adjustable. For example, some embodiments may characterize wavelengths of 285 nm as UVC. 
     The light source  204  may be, for example, a fluorescent bulb, a light emitting diode (LED), a low-pressure, e.g., mercury (Hg) bulb, or an excited dimer (excimer) lamp/laser. Combinations of different light sources could be used in some embodiments. Generally, the light source  204  is selected to ensure that the curing temperature does not exceed the temperature at which the ink  208  begins to sublime. For example, light source  204  of  FIG.  2    is a UV LED lamp that generates low heat output and can be used for a wider range of former types. UV LED lamps are associated with lower power consumption, longer lifetimes, and more predictable power output. 
     Other curing processes may also be used, such as epoxy (resin) chemistries, flash curing, and electron beam technology. One skilled in the art will appreciate that many different curing processes could be adopted that utilize specific timeframes, intensities, rates, etc. The intensity may increase or decrease linearly or non-linearly, e.g., exponentially, logarithmically. In some embodiments, the intensity may be altered using a variable resistor or alternatively by applying a pulse-width-modulated (PWM) signal to the diodes in the case of an LED light source. 
       FIG.  3    illustrates a planar view of components of a vacuum conveyor system  300  for inkjet printing with adjustment to a covered area, in accordance with one or more embodiments. The components of the vacuum conveyor system  300  shown in  FIG.  3    include a substrate transportation system and a vacuum platen  324 . In embodiments, the substrate transportation system can be a belt  304 . Additional components of the vacuum conveyor system  300  include components of the computer system  700  illustrated and described in more detail with reference to  FIG.  7   . Likewise, other embodiments include different and/or additional components, or be connected in a different way. 
     The vacuum conveyor system  300  is used for inkjet printing, and uses a vacuum chamber  416  (see  FIG.  4   ) connected to one or more vacuum pumps for providing suction to a vacuum platen  324  as part of the media transport. A substrate  532  to be printed is carried on a substrate transportation system over the vacuum platen  324  that has multiple openings. In some embodiments, the substrate transportation system is an air-transmissive belt  304 . An example substrate  532  is illustrated and described in more detail with reference to  FIG.  5 B . The vacuum platen  324  draws air into the apertures or openings  332  of the vacuum chamber  416 , creating a pressure differential between the upper and lower faces of the substrate  532  that flattens the substrate  532  against the vacuum platen  324 , with the belt  304  sliding over the vacuum platen  324  to feed the substrate  532  past the printing device. An example printing device  106  is illustrated and described in more detail with reference to  FIG.  1   . The printing device can be a thermal inkjet pen that reciprocates over the substrate in a scan direction perpendicular to the feed direction  308 , and which lays down successive swaths of ink droplets to generate a printed image on the substrate  532 . In some embodiments, the vacuum platen  324  is heated to facilitate rapid drying of aqueous ink. The vacuum (suction) generated secures the substrate  532  in a flat stable position as the ink dries. 
     In the embodiments described herein, the vacuum conveyor system  300  secures the substrate  532  to the belt  304  by suction. The belt  304  of the vacuum conveyor system  300  supports the substrate  532  being inkjet printed. In some embodiments, the belt  304  moves the substrate  532  from a first side  536  of the vacuum conveyor system  300  to a second side  540  of the vacuum conveyor system  300  opposite the first side  536 . The first side  536  and the second side  540  of the vacuum conveyor system  300  are illustrated and described in more detail with reference to  FIG.  5 A . In some embodiments, the vacuum platen  324  is further configured to flatten the substrate  532  to the belt  304 . 
     The belt  304  defines multiple perforations  312 ,  316  positioned to convey suction from the vacuum platen  324  to the substrate  532  to secure the substrate  532  to a second surface of the belt  304 . The second surface of the belt  304  faces away from the vacuum platen  324 , and the substrate  532  lies on the second surface of the belt  304 . In some embodiments, the multiple perforations  312 ,  314  are arranged in multiple rows along the length  520  of the vacuum platen  324 . The vacuum platen  324  defines openings  332  corresponding to the multiple perforations  312 ,  316 . The openings  332  are arranged according to the multiple rows. In some embodiments, each actuator of the multiple first actuators  404  is configured to expand to block perforations in a respective row of the multiple rows. The multiple first actuators  404  are sometimes referred to as a first array of actuators  404 . The multiple first actuators  404  are illustrated and described in more detail with reference to  FIG.  4   . In some embodiments, one or more actuators  524  of the multiple first actuators  404  are configured to expand to decrease leakage of suction provided by the vacuum conveyor system  300  from areas of the belt  304  of the vacuum conveyor system  300  lacking contact with the substrate  532 . The one or more actuators  524  are illustrated and described in more detail with reference to  FIG.  5 C . 
     The belt  304  of the vacuum conveyor system  300  moves the substrate  532  along the vacuum conveyor system  300  for inkjet printing of the substrate  532 . In some embodiments, the belt  304  is operably coupled to the vacuum chamber  416  and runs from a first side  536  of the vacuum chamber  416  to a second side  540  of the vacuum chamber  416 . The belt  304  includes a first surface  328  proximal to the vacuum chamber  416  and a second surface opposite the first surface  328  and distal to the vacuum chamber  416 . The belt  304  is configured to convey the substrate  532  on the second surface from the first side  536  to the second side  540  for inkjet printing of the substrate  532 . 
       FIG.  4    is a cross-sectional view of a vacuum conveyor system  400  for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments.  FIG.  4    shows a cross-section perpendicular to the feed direction  308 . The vacuum conveyor system  400  includes a vacuum table including a vacuum chamber  416 , multiple first actuators  404 , multiple second actuators  408 , and a substrate transportation system. The multiple second actuators  408  are sometimes referred to as a second array of actuators. Likewise, other embodiments include different and/or additional components, or are connected in a different way. 
     The vacuum table is a system for holding a substrate  532  during printing. The substrate  532  is illustrated and described in more detail with reference to  FIG.  5 B . The vacuum table includes a perforated tabletop having the vacuum chamber  416  and a vacuum pump to keep the vacuum chamber  416  below ambient pressure. As shown in  FIG.  4   , the vacuum table includes the vacuum chamber  416  configured to secure the substrate  532  for inkjet printing of the substrate  532 . The vacuum chamber  416  is configured to secure the substrate  532  by providing suction to the substrate  532 . The multiple first actuators  404  are sometimes referred to as a first array of actuators and the multiple second actuators  408  are sometimes referred to as a second array of actuators. 
     The combination of both the arrays of actuators  404 ,  408  block the flow of air in the direction  412  passing through the openings  332  of the vacuum platen  324 . In some embodiments, at least one actuator of the multiple first actuators  404  and the multiple second actuators  408  is an extensible pneumatic or hydraulic actuator. Such actuators convert energy (e.g., of compressed fluid) into mechanical motion to regulate a length that the actuator is extended. For adequate performance: 1) the actuators are surrounded by elements  420  (e.g., a guiding channel) against which the actuators can apply pressure in order to prevent the flow through the openings  332  of the vacuum platen  324 , and 2) the actuators have the ability to move longitudinally with respect to the surrounding elements  420  in order to conduct the previously described expansion-retraction sequence. Suitable actuators for this purpose include pneumatic or hydraulic actuators with high extensibility ratios (i.e., a length ratio between fully extended and fully retracted states) in order to reduce the space they take. Some examples include: 1) bellow-shaped actuators, 2) a rolled-up bladder (like a water hose) in which the application of pressure from the free end unrolls the actuator and expands it longitudinally, or 3) a rolled-up bladder turned inside out at the free tip in which the pressure induces eversion of the bladder and longitudinal expansion. An important aspect in the selection of the actuator for use is how to make possible the application of pressure to seal the flow while allowing free longitudinal movement. The third actuator proposed above has obvious advantages in this regard as the eversion motion means that there is no relative motion between the actuator walls and the surrounding elements  420  during longitudinal expansion, such that the friction force between these two elements does not impede motion. For the kinds of actuators where relative motion takes place, different methods based on hydrodynamic lubrication can be employed to reconcile these apparently opposing requirements. 
     In some embodiments, the controller  440  is coupled to the one or more actuators  524  and the multiple second actuators  408 . The controller  440  is configured to cause the one or more actuators  524  of the multiple first actuators  404  to expand across the length  520  of the vacuum chamber  416  as a substrate width  552  decreases. The substrate width  552  is shown in more detail in  FIG.  5 B . The controller  440  causes the multiple second actuators  408  to retract along the length  520  of the vacuum chamber  416  as the length covered by the substrates  560  contacting the substrate transportation system increases. The length covered by the substrates  560  is shown in more detail in  FIG.  5 B . 
     A controller  440  is coupled to the multiple first actuators  404  and the multiple second actuators  408 . The controller  440  is implemented using components of the computer system  700  illustrated and described in more detail with reference to  FIG.  7   . The controller  440  selects one or more actuators  524  of the multiple first actuators  404  and causes the one or more actuators  524  to expand and retract across a length  520  of the vacuum table. The length  520  is illustrated in more detail with reference to  FIG.  5 A . The one or more actuators  524  are illustrated in more detail with reference to  FIG.  5 C . In some embodiments, expanding and retracting the one or more actuators  524  includes controlling, by the controller  440 , a cavity length of the one or more actuators  524  using pressurized fluid. The controller  440  causes the multiple second actuators  408  to expand and retract along the length  520  of the vacuum table. In some embodiments, one or more solenoid valves  432  are coupled to the one or more actuators  524  of the multiple first actuators  404 . The controller  440  is configured to select the one or more actuators  524  using the one or more solenoid valves  432 . A solenoid valve is a control element that can shut off, release, or distribute fluid to the multiple first actuators  404 . In other embodiments, the controller  440  selects another one or more actuators  528  from the multiple first actuators  404  using the one or more solenoid valves  432  that are coupled to the one or more actuators  528 . The one or more actuators  528  are illustrated in more detail with reference to  FIG.  5 C . 
       FIGS.  5 A,  5 B,  5 C, and  5 D  illustrate planar views of a vacuum conveyor system  300  for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. These figures show, in chronological order, the typical sequence of loading and unloading of substrates the vacuum conveyor system  300 . The vacuum conveyor system  300  is illustrated and described in more detail with reference to  FIG.  3   . Likewise, other embodiments include different and/or additional components, or are connected in a different way. 
       FIG.  5 A  shows the vacuum conveyor system  300  in a first configuration  504 . The vacuum conveyor system  300  is used to ensure that a substrate is held flat below the printheads. The efficiency of the vacuum conveyor system  300  is increased by the embodiments described herein when the active area is restricted to the region covered by the substrate. In the first configuration  504 , a substrate  532  has not yet been placed on the vacuum table. The substrate  532  is illustrated and described in more detail with reference to  FIG.  5 B . To prevent leakage of the suction and decrease in the vacuum pressure in the vacuum chamber  416 , the actuators  404 ,  408  are expanded. The vacuum chamber  416  and the actuators  404 ,  408  are illustrated and described in more detail with reference to  FIG.  4   . 
     A substrate transportation system is operably coupled to the vacuum table and runs across a length  520  of the vacuum table from a first side  536  of the vacuum table to a second side  540  of the vacuum table. In some embodiments, the substrate transportation system includes a substrate transportation system illustrated and described in more detail with reference to  FIG.  3   . In embodiments, the substrate transportation system can be the belt  304 . The belt  304  is configured to convey the substrate  532  from the first side  536  to the second side  540  for inkjet printing. In some embodiments, the multiple second actuators  408  are further configured to expand across the length  520  of the vacuum table from the second side  540  to the first side  536  to decrease a suction length  556  of the area  548  of suction where the substrate  532  contacts the belt  304 . The suction length  556  and area  548  of suction are illustrated and described in more detail with reference to  FIG.  5 D . 
       FIG.  5 B  shows the vacuum conveyor system  300  in a second configuration  508  where the vacuum conveyor system is being loaded with substrates. In the second configuration  508 , the substrate  532  is entering on the left (entry) portion of the substrate transportation system (e.g., belt  304 ) on the vacuum table. The vacuum table is illustrated and described in more detail with reference to  FIG.  4   . To prevent leakage of the suction and decrease in the vacuum pressure in the vacuum chamber  416 , some of the actuators  404  are expanded. All of the actuators  408  are expanded. The vacuum chamber  416  is illustrated and described in more detail with reference to  FIG.  4   . 
     The substrate  532  is located outside the vacuum chamber  416  and between the first side  534  and the second side  540  as shown by  FIG.  5 B . The first side  534  and the second side  540  are shown by  FIG.  5 A . The multiple first actuators  404  are retracted along the length  520  of the vacuum table from the second side  540  to the first side  534  to increase the suction width  544  in accordance with the substrate width  552 . The length  520  is shown by  FIG.  5 A . The suction width  544  is shown by  FIG.  5 D . In some embodiments, the multiple first actuators  404  are operably coupled to the first side  536  of the vacuum chamber  416  and configured to expand from the first side  536  to the second side  540  of the vacuum chamber  416  to decrease the suction width  544  of the area of suction  548  provided by the vacuum chamber  416  to secure the substrate  532  for inkjet printing. In some embodiments, the multiple second actuators  408  are operably coupled to the second side  540  and configured to retract from the first side  536  to the second side  540  to increase a suction length  556  of the area  548  of the suction as the total length  560  of the substrate  532  contacting the belt  304  increases. The suction length  556  is shown by  FIG.  5 D . In some embodiments, the controller  440  has feedback mechanisms (e.g., position sensors) that enables synchronization of the movement of the tip of the multiple second actuators  408  and that of the leading edge of the substrate  532  to minimize the leakage area of the vacuum chamber  416 . In some embodiments, the multiple first actuators  404  and the multiple second actuators  408  are arranged in multiple rows along the width  568  of the vacuum chamber  416 . 
     In some embodiments, the multiple first actuators  404  are further configured to retract from the second side  540  to the first side  536  to increase the suction width  544  as the substrate width  552  increases. The multiple second actuators  408  are further configured to expand from the second side  540  to the first side  536  to decrease the suction length  556  before the substrate  532  contacts the belt  304 . The controller  440  (see  FIG.  4   ) expands the multiple second actuators  408  of the vacuum conveyor system  300  to decrease the suction length  556  of the area  548  of suction. The controller  440  retracts the multiple second actuators  408  of the vacuum conveyor system  300  to increase the suction length  556  as the substrate  532  moves along the vacuum conveyor system  300 . In some embodiments, the multiple second actuators  408  are expanded prior to the substrate  532  contacting the belt  304 . The multiple first actuators  404  are operably coupled to the first side  536  and configured to expand to decrease the suction width  544  of the area  548  of suction provided by the vacuum chamber  416  in accordance with the substrate width  552 . 
     In some embodiments, the multiple second actuators  408  are operably coupled to the second side  540  and configured to retract to increase the suction length  556  of the area  548  of suction in accordance with the total length  560  of the substrates contacting the belt  304 . The multiple first actuators  404  are configured to expand to decrease leakage of suction provided by the vacuum chamber  416  from areas of the belt  304  lacking contact with the substrate  532 . The multiple second actuators  408  are further configured to expand to decrease leakage of suction provided by the vacuum chamber  416  from areas of the belt  304  lacking contact with the substrate  532 . In some embodiments, the controller  440  causes another one or more actuators  528  (see  FIG.  5 C ) of the multiple first actuators  404  to expand across the length  520  of the vacuum conveyor system  300  in accordance with the substrate width  552  of the substrate  532 . The controller  440  causes the multiple second actuators  408  to retract as the total length  560  of the substrates contacting the belt  304  of the vacuum conveyor system  300  increases. 
       FIG.  5 C  shows the vacuum conveyor system  300  in a third configuration  512  where the total length of the vacuum conveyor is covered by substrates. In the third configuration  512 , the substrate  532  has moved from the first side  536  of the vacuum table to the second side  540  of the vacuum table. Another substrate  564  is now occupying the left portion of a substrate transportation system (e.g., the belt  304 ) and following the substrate  532  to be printed after the substrate  532  is printed. 
     The controller  440  is coupled to the multiple first actuators  404  and the multiple second actuators  408 . The controller  440  is illustrated and described in more detail with reference to  FIG.  4   . In this third configuration, the retraction or expansion of the multiple first actuators  404  and the multiple second actuators  408  is not modified. This is because both the total length  560  of the substrates contacting the belt  304  of the vacuum conveyor system  300  and the substrate width  552  of the substrate  532  remain invariable. 
       FIG.  5 D  shows the vacuum conveyor system  300  (see  FIG.  3   ) in a fourth configuration  516  where the vacuum conveyor system is being unloaded of substrates. In the fourth configuration  516 , the substrate  564  has moved from the first side  536  (see  FIG.  5 A ) of the vacuum table to the second side  540  of the vacuum table. The substrate  564  is shown shortly about to exit the vacuum table on the second side  540  after the inkjet printing. There is no other substrate on the left hand portion of a substrate transportation system (e.g., the belt  304 ). 
     The multiple first actuators  404  (see  FIG.  5 B ) are operably coupled to the first side  536  and located within the vacuum table. Some of the multiple first actuators  404  are expanded across the length  520  of the vacuum table from the first side  536  to the second side  540  to decrease a suction width  544  of an area  548  of suction provided by the vacuum chamber in accordance with a substrate width  552  (see  FIG.  5 B ). During this phase, the controller  440  (see  FIG.  4   ) of the vacuum conveyor system  300  expands the rest of the multiple first actuators  404  in order to follow the trailing edge of the last substrate  564  on the belt. In some embodiments, the controller  440  has feedback mechanisms (e.g., position sensors) that allow synchronization of the movement of the tip of the first actuators  404  and that of the leading edge of the substrate  532  to minimize the leakage area of the vacuum chamber  416 . The multiple second actuators  408  are operably coupled to the second side  540  and located within the vacuum table. During this phase, the multiple second actuators remain retracted along the length  520  of the vacuum table. 
     In some embodiments, the suction width  544  and the substrate width  552  are each oriented perpendicular to the direction  308  along the length  520  of the vacuum chamber  416 . The suction width  544  and the substrate width  552  are each oriented perpendicular to the direction  308  of motion of the belt  304 . In some embodiments, the previously described sequence is simplified by using a separate system for adjusting to the substrate width. In such embodiments, the multiple first actuators  404  are all configured in the same state, either retracted or expanded. 
       FIG.  6    is a flow diagram illustrating a process for a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. In some embodiments, the process of  FIG.  6    is performed using a vacuum conveyor system, e.g., the system  300  illustrated and described in more detail with reference to  FIG.  3   . In other embodiments, the process of  FIG.  6    is performed using components of the computer system  700  illustrated and described in more detail with reference to  FIG.  7   . Likewise, other embodiments include different and/or additional steps, or are performed in a different order. 
     In step  604 , a controller  440  (see  FIG.  4   ) of the vacuum conveyor system  300  expands one or more actuators  524  of multiple first actuators  404  of the vacuum conveyor system  300  to decrease a suction width  544  (see  FIG.  5 D ) of an area of suction  548  provided by the vacuum conveyor system  300  in accordance with a substrate width  552  of one or more substrates  532  being inkjet printed using the vacuum conveyor system  300 . Another one or more actuators  528  of the multiple first actuators  404  are retracted. The controller  440  can be computer circuitry or software and is implemented using components of the computer system  700  illustrated and described in more detail with reference to  FIG.  7   . 
     In step  608 , the controller  440  retracts multiple second actuators  408  (see  FIG.  5 B ) of the vacuum conveyor system  300  to increase a suction length  556  of the area  548  of suction. The multiple second actuators  408  were previously expanded. In some embodiments, the multiple second actuators  408  are operably coupled to a second side  540  (see  FIG.  5 A ) and configured to expand or retract from a first side  536  to the second side  540  to modify the suction length  556  of the area  548  of the suction as a total length  560  of the one or more substrates  532  contacting a substrate transportation system (e.g., the belt  304 ) increases. The suction length  556  is shown by  FIG.  5 D . In some embodiments, the multiple first actuators  404  and the multiple second actuators  408  are arranged in multiple rows along a width  568  (see  FIG.  5 A ) of the vacuum chamber  416 . 
     In step  612 , a substrate transportation system of the vacuum conveyor system  300  moves the one or more substrates  532  along the vacuum conveyor system  300  for inkjet printing of the one or more substrates  532 . For example, the belt  304  of the vacuum conveyor system  300  moves the substrate  532  along the vacuum conveyor system  300  for inkjet printing of the substrate  532 . The belt  304  defines multiple perforations  312 ,  316  (see  FIG.  3   ) positioned to convey suction from a vacuum platen  324  to the substrate  532  to secure the substrate  532  to a second surface of the belt  304 . The second surface of the belt  304  faces away from the vacuum platen  324 , and the substrate  532  lies on the second surface of the belt  304 . In some embodiments, the multiple perforations  312 ,  314  are arranged in multiple rows along a length  520  (see  FIG.  5 A ) of the vacuum platen  324 . The vacuum platen  324  defines openings  332  corresponding to the multiple perforations  312 ,  316 . 
     In step  616 , the controller  440  expands the second one or more actuators  528  of the first plurality of actuators  404  to decrease the suction length  556  (see  FIG.  5 D ) as the one or more substrates  532  move along the vacuum conveyor system  300 . 
       FIG.  7    is a block diagram illustrating a computer system  700  to control a vacuum conveyor system for inkjet printing with adjustment to the covered area, in accordance with one or more embodiments. Components of the example computer system  700  can be used to implement the systems  100 ,  200 ,  300 , and  400  illustrated and described in more detail with reference to  FIGS.  1 ,  2 ,  3 , and  4   . At least some operations described with reference to  FIG.  6    can be implemented on the computer system  700 . Likewise, other embodiments include different and/or additional components, or be connected in a different way. 
     The computer system  700  can include one or more central processing units (“processors”)  702 , main memory  706 , non-volatile memory  710 , network adapter  712  (e.g., network interface), video display  718 , input/output devices  720 , control device  722  (e.g., keyboard and pointing devices), drive unit  724  including a storage medium  726 , and a signal generation device  730  that are communicatively connected to a bus  716 . The bus  716  is illustrated as an abstraction that represents one or more physical buses and/or point-to-point connections that are connected by appropriate bridges, adapters, or controllers. The bus  716 , therefore, can include a system bus, a Peripheral Component Interconnect (PCI) bus or PCI-Express bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), an IIC (I2C) bus, or an Institute of Electrical and Electronics Engineers (IEEE) standard 1394 bus (also referred to as “Firewire”). 
     The computer system  700  can share a similar computer processor architecture as that of a desktop computer, tablet computer, personal digital assistant (PDA), mobile phone, game console, music player, wearable electronic device (e.g., a watch or fitness tracker), network-connected (“smart”) device (e.g., a television or home assistant device), virtual/augmented reality system (e.g., a head-mounted display), or another electronic device capable of executing a set of instructions (sequential or otherwise) that specify action(s) to be taken by the computer system  700 . 
     While the main memory  706 , non-volatile memory  710 , and storage medium  726  (also called a “machine-readable medium”) are shown to be a single medium, the term “machine-readable medium” and “storage medium” should be taken to include a single medium or multiple media (e.g., a centralized/distributed database and/or associated caches and servers) that store one or more sets of instructions  728 . The term “machine-readable medium” and “storage medium” shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the computer system  700 . 
     In general, the routines executed to implement the embodiments of the disclosure may be implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions (collectively referred to as “computer programs”). The computer programs typically include one or more instructions (e.g., instructions  704 ,  708 ,  728 ) set at various times in various memory and storage devices in a computing device. When read and executed by the one or more processors  702 , the instruction(s) cause the computer system  700  to perform operations to execute elements involving the various aspects of the disclosure. 
     Moreover, while embodiments have been described in the context of fully functioning computing devices, those skilled in the art will appreciate that the various embodiments are capable of being distributed as a program product in a variety of forms. The disclosure applies regardless of the particular type of machine or computer-readable media used to actually effect the distribution. 
     Further examples of machine-readable storage media, machine-readable media, or computer-readable media include recordable-type media such as volatile and non-volatile memory devices  710 , floppy and other removable disks, hard disk drives, optical disks (e.g., Compact Disk Read-Only Memory (CD-ROMS), Digital Versatile Disks (DVDs)), and transmission-type media such as digital and analog communication links. 
     The network adapter  712  enables the computer system  700  to mediate data in a network  714  with an entity that is external to the computer system  700  through any communication protocol supported by the computer system  700  and the external entity. The network adapter  712  can include a network adapter card, a wireless network interface card, a router, an access point, a wireless router, a switch, a multilayer switch, a protocol converter, a gateway, a bridge, a bridge router, a hub, a digital media receiver, and/or a repeater. 
     The network adapter  712  may include a firewall that governs and/or manages permission to access/proxy data in a computer network and tracks varying levels of trust between different machines and/or applications. The firewall can be any number of modules having any combination of hardware and/or software components able to enforce a predetermined set of access rights between a particular set of machines and applications, machines and machines, and/or applications and applications (e.g., to regulate the flow of traffic and resource sharing between these entities). The firewall may additionally manage and/or have access to an access control list that details permissions including the access and operation rights of an object by an individual, a machine, and/or an application, and the circumstances under which the permission rights stand. 
     In additional embodiments, a system includes a substrate transportation system operably coupled to a vacuum chamber and running from a first side of the vacuum chamber to a second side of the vacuum chamber. The substrate transportation system includes a first surface proximal to the vacuum chamber and a second surface opposite the first surface. The second surface is distal to the vacuum chamber. The substrate transportation system is configured to convey a substrate on the second surface from the first side to the second side for inkjet printing of the substrate. Multiple first actuators are operably coupled to the first side and configured to expand to decrease a suction width of an area of suction provided by the vacuum chamber in accordance with a substrate width. Multiple second actuators are operably coupled to the second side and configured to retract to increase a suction length of the area of suction in accordance with a total length of the one or more substrates contacting the substrate transportation system. 
     In some embodiments, a controller is electrically coupled to the multiple first actuators and the multiple second actuators. The controller is configured to cause one or more actuators of the multiple first actuators to expand across a length of the vacuum chamber as the substrate width decreases. The multiple second actuators retract along the length of the vacuum chamber as the total length of the one or more substrates contacting the substrate transportation system increases. 
     In some embodiments, the suction width and the substrate width are each oriented perpendicular to a direction along a length of the vacuum chamber. 
     In some embodiments, the suction width and the substrate width are each oriented perpendicular to a direction of motion of a belt. 
     In some embodiments, the belt defines multiple perforations positioned to convey suction from the vacuum chamber to the substrate to secure the substrate to the second surface. 
     In some embodiments, the multiple perforations are arranged in multiple rows along the length of the vacuum table. 
     In some embodiments, the vacuum chamber defines openings corresponding to the multiple perforations, the openings arranged according to the multiple rows. 
     In some embodiments, each actuator of the multiple first actuators is configured to expand to block perforations in a respective row of the multiple rows. 
     In some embodiments, the multiple first actuators are configured to expand to decrease leakage of suction provided by the vacuum chamber from areas of the belt lacking contact with the substrate. 
     In some embodiments, the multiple second actuators are further configured to expand to decrease leakage of suction provided by the vacuum chamber from areas of the belt lacking contact with the substrate. 
     In some embodiments, a controller of a vacuum conveyor system expands one or more actuators of multiple first actuators of the vacuum conveyor system to decrease a suction width of an area of suction provided by the vacuum conveyor system as a substrate being inkjet printed using the vacuum conveyor system moves along a length of the vacuum conveyor system. The controller retracts multiple second actuators of the vacuum conveyor system to increase a suction length of the area of suction as the substrate moves along the length of the vacuum conveyor system. 
     In some embodiments, a belt of the vacuum conveyor system supports the substrate being inkjet printed. The belt moves the substrate from a first side of the vacuum conveyor system to a second side of the vacuum conveyor system opposite the first side. 
     In some embodiments, the one or more actuators are first one or more actuators. Second one or more actuators of the multiple first actuators are expanded to decrease the suction width of the area of suction prior to the substrate moving along the length of the vacuum conveyor system. 
     In some embodiments, the controller expands the multiple second actuators to decrease the suction length of the area of suction prior to the substrate moving along the length of the vacuum conveyor system. 
     In some embodiments, the one or more actuators are first one or more actuators. The controller causes second one or more actuators of the multiple first actuators to expand across the length of the vacuum conveyor system in accordance with a substrate width of the substrate. 
     In some embodiments, the controller causes the multiple second actuators to retract as the length of the substrates contacting a belt of the vacuum conveyor system increases. 
     In some embodiments, the suction width and a substrate width of the substrate are each oriented perpendicular to a direction along the length of the vacuum conveyor system. 
     In some embodiments, the suction width and a substrate width of the substrate are each oriented perpendicular to a direction of motion of a belt of the vacuum conveyor system. 
     In some embodiments, the one or more actuators are configured to expand to decrease leakage of suction provided by the vacuum conveyor system from areas of a belt of the vacuum conveyor system lacking contact with the substrate. 
     In some embodiments, a system includes one or more computer processors and a non-transitory, computer-readable storage medium storing computer instructions, which when executed by the one or more computer processors cause the one or more computer processors to expand one or more actuators of multiple first actuators of the system to decrease a suction width of an area of suction provided by the system as a substrate being inkjet printed using the system moves along a length of the system. Multiple second actuators of the system are retracted to increase a suction length of the area of suction as the substrate moves along the length of the system. 
     The techniques introduced here can be implemented by programmable circuitry (e.g., one or more microprocessors), software and/or firmware, special-purpose hardwired (i.e., non-programmable) circuitry, or a combination of such forms. Special-purpose circuitry can be in the form of one or more application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc. 
     The description and drawings herein are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known details are not described in order to avoid obscuring the description. Further, various modifications may be made without deviating from the scope of the embodiments. 
     The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms that are used to describe the disclosure are discussed above, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the disclosure. For convenience, certain terms may be highlighted, for example using italics and/or quotation marks. The use of highlighting has no influence on the scope and meaning of a term; the scope and meaning of a term is the same, in the same context, whether or not it is highlighted. It will be appreciated that the same thing can be said in more than one way. One will recognize that “memory” is one form of a “storage” and that the terms may on occasion be used interchangeably. 
     Consequently, alternative language and synonyms may be used for any one or more of the terms discussed herein, but no special significance is to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any term discussed herein is illustrative only and is not intended to further limit the scope and meaning of the disclosure or of any exemplified term. Likewise, the disclosure is not limited to various embodiments given in this specification. 
     It is to be understood that the embodiments and variations shown and described herein are merely illustrative of the principles of this invention and that various modifications may be implemented by those skilled in the art.