Patent Publication Number: US-11034164-B2

Title: Printing path that travels in different directions through dryer

Description:
BACKGROUND 
     Digital printing technologies rely on the adhesion of printing fluid particles to a print target (e.g., a web of material or a build bed) to produce a printed item. The location of the printing fluid particles on the print target, and in some cases the phase change of the printing fluid particles, is electrically controlled to produce a desired image. Some digital printing technologies include mechanisms for adhering printing fluid particles to both sides of a print target. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an example system of the present disclosure; 
         FIG. 2  illustrates a flowchart of an example method for printing on a print target; and 
         FIG. 3  depicts a high-level block diagram of an example computer that can be transformed into a machine capable of performing the functions described herein. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure broadly describes an apparatus, method, and non-transitory computer-readable medium for printing on a print target using a printing path that travels in at least two different directions through a dryer. As discussed above, some digital printing devices include two print sections that are positioned to allow for printing on both sides of a print target (which in some cases may comprise a continuous web). Printing on both sides of the print target may introduce challenges in terms of drying. For instance, it is difficult to maintain a compact size for the printing device as a whole while providing both print sections with access to a dryer that is large enough to fully dry the printing fluid. 
     Examples of the present disclosure provide a printing device and method for printing on one or both sides of a continuous web of print target. Examples of the printing device include two print sections (one for each side of the print target) that share the same dryer for drying fluid. The printing path that the print target travels through the print sections and dryer takes a serpentine shape having at least two switchbacks (e.g., changes in direction). In some examples, there may be as many as four switchbacks, or even more than four switchbacks. The switchbacks cause the printing path to travel in opposite directions when it moves through the dryer for the first and second times. This arrangement allows two similar print sections to print, and a shared dryer to dry, both sides of a continuous web of print target, without flipping the print target during printing and/or drying. This compact configuration will allow the printing device to maintain smaller overall dimensions, which will make it easier to fit the printing device into shipping containers and some customer premises. It also allows two or more different types of dryers to be used to dry the print target at different points in the drying process, and even for dryers to be added after deployment of the printing device. 
       FIG. 1  illustrates an example system  100  of the present disclosure. In one example, the system  100  comprises a digital printing device, such as an inkjet or drop-on-demand printing device, that prints on a continuous web of print target. In one example, the system  100  generally includes a first print section  102 , a second print section  104 , and a dryer  106 . A printing path  108  carries the print target through the device  100 , including through the first print section  102 , the second print section  104 , and the dryer  106 . Any of these components may be controlled by a high-level controller (not shown), potentially in combination with a lower-level controller. The high-level controller may be implemented in a computer, as discussed in connection with  FIG. 3 . The system  100  includes other components as well (e.g., upstream and downstream components, such as unwinders, rewinders, or finishing devices that cut, stack, perforate, fold, glue and perform other operations to the system output, and other components) that are not directly pertinent to the present disclosure and are thus omitted for clarity. Thus,  FIG. 1  represents a simplified illustration of the system  100 . 
     Each of the first print section  102  and the second print section  104  is configured to dispense fluid (e.g., printing fluid, toner, detailing agent, or the like) onto one side of the print target, such that the fluid recreates an input image. In particular, the first print section  102  is configured to dispense fluid onto a first side of the print target to recreate a first image, while the second print section  104  is configured to dispense fluid onto a second side of the print target (opposite the first side of the print target) to recreate a second image. To this end, each of the first print section  102  and the second print section  104  may comprise a plurality of fluid ejection arrays (e.g., print bars), where each fluid ejection array further comprises a plurality of fluid ejection dies (e.g., print heads) that eject fluid in one or more colors. For instance, each of the first print section  102  and the second print section  104  may comprise four, six, ten, or any other number of fluid ejection arrays. The printing path  108  is configured to present the first side of the print target to the first print section  102  and the second side of the print target to the second print section  104 . Thus, although the first print section  102  and the second print section  104  may be configured in a substantially similar manner and orientation (e.g., the same components arranged in the same manner), the printing path  108  is configured such that the first and second sides of the web are presented to the first print section  102  and the second print section  104 , respectively, in the correct orientation for printing. 
     In one example, the first print section  102  and the second print section  104  are positioned side-by-side, as illustrated in  FIG. 1 . That is, the first print section  102  and the second print section  104  are spaced apart from each other laterally. In one example, the first print section  102  and the second print section  104  are configured similarly and mirrored across the lateral separation. The dryer  106  is positioned adjacent to (e.g., below) the first print section  102  and the second print section  104 . In one example, the length, l, of the dryer  106  is approximately equal to (e.g., equal within a few inches&#39; tolerance of) l 1 +l 2 +l 3 , where l 1  is the length of the first print section  102 , l 2  is the length of the second print section  104 , and l 3  is the length of a lateral separation or space between the first print section  102  and the second print section  104 . 
     The dryer  106  may comprise one or more drying units  110   1 - 110   n  (hereinafter collectively referred to as “drying units  110 ”). In one example, the drying units  110  are arranged along the length l of the dryer  106 , and may be stacked. In one example, the drying units  110  comprise two or more different types of drying units (e.g., based on two or more different types of drying mechanisms, such as infrared light, light emitting diode, radio frequency, forced hot air, or the like). The arrows illustrated within the drying units  110  represent one or more means for adding energy to (e.g., drying) the print target. The drying units  110  may be relatively “dumb,” i.e., configured in one way per print job. Alternatively, the drying units  110  may be more sophisticated, and may adapt constantly to the print job as it is printing and drying. A passive (e.g., no energy is being added) section  114  may be defined between at least two of the drying units  110 . This passive section  114  may be used to recirculate some of the hot air generated by the dryer  106 . For example, hot air generated from a first pass of the print target through the dryer  106  could be recycled and used to preheat the dryer  106  for a second pass of the print target through the dryer. 
     The dryer  106  includes at least two drying lanes  112   1  and  112   2  (hereinafter collectively referred to as “drying lanes  112 ”) that are traversed by the printing path  108 . A first drying lane  112   1  moves in a first direction (e.g., from the first print section  102  toward the second print section  104 ), while a second drying lane  112   2  moves in the opposite direction (i.e., approximately 180 degrees from the first direction, for example from the second print section  104  toward the first print section  102 ). Each of the drying lanes  112  exposes the print target on the printing path  108  to one or more of the drying units  110 . The first drying lane  112   1  and the second drying lane  112   2  may be orientated substantially parallel to each other (e.g., parallel within a few degrees&#39; tolerance), and each of the first drying lane  112   1  and the second drying lane  112   1  may be orientated in a substantially perpendicular manner relative to the passive section(s)  114  of the dryer  106 . 
     As illustrated, the printing path  108  that the print target travels through the first and second print sections  102  and  104  and the dryer  106  takes a serpentine shape having multiple switchbacks (two of which, i.e.,  116   1  and  116   2  are labeled in  FIG. 1 ). The printing path  108  carries the print target in a first direction from the unwinder of the system  100  (not shown) into the first print section  102 , which deposits fluid (e.g., printing fluid, toner, detailing agent, or the like) on a first side of the print target. Upon exiting the first print section  102 , the printing path  108  reverses direction and carries the print target through the dryer  106  for a first time (i.e., along the first drying lane  112   1 ), thereby drying the fluid on the first side of the print target. Upon exiting the dryer  106  for the first time, the printing path  108  reverses direction again and carries the print target through the second print section  104 , which may deposit fluid on the second side of the print target (if dual-sided printing is desired). Upon exiting the second print section  104 , the printing path  108  carries the print target through the dryer  106  for a second time (i.e., along the second drying lane  112   2 ), thereby drying any fluid on the second side of the print target. The printing path  108  may reverse direction at least once after exiting the second print section  104  and prior to entering the dryer  106  for the second time, such that the printing path  108  travels in opposite directions the first and second times it moves through the dryer  106  (i.e., using the first and second printing lanes  112   1  and  112   2  to carry the print target in opposite directions). Upon exiting the dryer  106  for the second time, the printing path  108  may travel toward a vision system (not shown) of the system  100  which provides feedback to the system  100 . 
       FIG. 2  illustrates a flowchart of an example method  200  for printing on a print target. The method  200  includes blocks for printing and drying at least one side of a print target, as discussed above in connection with  FIG. 1 . The method  200  may be performed, for example, by the system  100  illustrated in  FIG. 1 . It will be appreciated, however, that the method  200  is not limited to implementation with the system illustrated in  FIG. 1 . 
     The method  200  begins in block  202 . In block  204 , the system  100  prints an image on a first side of a print target. The print target may be a continuous web of print target, as discussed above. In one example, the system  100  uses the first print section  102  to print the image on the first side of the print target. Thus, the paper path  108  may carry the print target from an unwinder of the system  100  and into the first print section in block  204 . 
     In block  206 , the system  100  dries the image printed on the first side of the print target. In one example, the paper path  108  may reverse direction to carry the print target from the first print section  104  and into the dryer  106 . Thus, the paper path  108  travels in a first direction for a first pass through the dryer  106  in block  206 . 
     In block  208  (illustrated in phantom), the system  100  may print an image on a second side of the print target that is opposite the first side of the print target. In one example, the system  100  uses the second print section  104  to print the image on the second side of the print target. Thus, the paper path  108  may reverse direction at least once to carry the print target from the dryer  106  and into the second print section in block  208 . In one example, the system  100  prints on the first side of the print target and subsequently prints on the second side of the print target without turning the print target over in between printing operations. 
     In block  210  (illustrated in phantom), the system  100  may dry the image printed on the second side of the print target. In one example, the paper path  108  may reverse direction to carry the print target from the second print section  104  and into the dryer  106 . Thus, the paper path  108  travels in a second direction for a second pass through the dryer  106  in block  210 . In one example, the second direction in which the paper path  108  travels for the second pass through the dryer  106  (e.g., in block  210 ) is the opposite (e.g., different by approximately 180 degrees) of the first direction that the paper path  108  travels for the first pass through the dryer  106  (e.g., in block  206 ). In one example, the system  100  dries the first side of the print target and subsequently dries the second side of the print target without turning the print target over in between drying operations. 
     The method  200  ends in block  212 . After all sides of the print target that have been printed on have been dried, the system  100  may deliver the print target to a vision system of the system  100 . The paper path  108  may or may not reverse direction to carry the print target from the dryer  106  to the vision system. 
       FIG. 3  depicts a high-level block diagram of an example computer that can be transformed into a machine capable of performing the functions described herein. Examples of the present disclosure modify the operation and functioning of the general-purpose computer to print on one or both sides of a web of print target, as disclosed herein. 
     As depicted in  FIG. 3 , the computer  300  comprises a hardware processor element  302 , e.g., a central processing unit (CPU), a microprocessor, or a multi-core processor, a memory  304 , e.g., random access memory (RAM) and/or read only memory (ROM), a module  305  for printing on one or both sides of a web of print target, and various input/output devices  306 , e.g., storage devices, including but not limited to, a tape drive, a floppy drive, a hard disk drive or a compact disk drive, a flash drive, a receiver, a transmitter, a speaker, a display, a speech synthesizer, a fiber optic communication line, an output port, an input port and a user input device, such as a keyboard, a keypad, a mouse, a microphone, and the like. Although one processor element is shown, it should be noted that the general-purpose computer may employ a plurality of processor elements. Furthermore, although one general-purpose computer is shown in the figure, if the method(s) as discussed above is implemented in a distributed or parallel manner for a particular illustrative example, i.e., the blocks of the above method(s) or the entire method(s) are implemented across multiple or parallel general-purpose computers, then the general-purpose computer of this figure is intended to represent each of those multiple general-purpose computers. Furthermore, a hardware processor can be utilized in supporting a virtualized or shared computing environment. The virtualized computing environment may support a virtual machine representing computers, servers, or other computing devices. In such virtualized virtual machines, hardware components such as hardware processors and computer-readable storage devices may be virtualized or logically represented. 
     It should be noted that the present disclosure can be implemented by machine readable instructions and/or in a combination of machine readable instructions and hardware, e.g., using application specific integrated circuits (ASIC), a programmable logic array (PLA), including a field-programmable gate array (FPGA), or a state machine deployed on a hardware device, a general purpose computer or any other hardware equivalents, e.g., computer readable instructions pertaining to the method(s) discussed above can be used to configure a hardware processor to perform the blocks, functions and/or operations of the above disclosed method(s). 
     In one example, instructions and data for the present module or process  305  for printing on one or both sides of a web of print target, e.g., machine readable instructions can be loaded into memory  304  and executed by hardware processor element  302  to implement the blocks, functions or operations as discussed above in connection with the method  200 . For instance, the module  305  may include a plurality of programming code components, including a printing component  308  and a drying component  310 . These programming code components may be included, for example, on a controller that controls a printing device configured in a manner similar to the system  100 . 
     The printing component  308  may be configured to identify on which sides of a print target to print (e.g., one side or both sides) and to activate the appropriate print sections of a system to print an image by dispensing fluid as the print target passes through the print sections. For instance, the printing component  308  may control at least some of the functions discussed above with respect to blocks  204  and  208  of the method  200 . 
     The drying component  310  may be configured to identify when particular drying units of a dryer should be activated, and to activate the drying units accordingly. For instance, depending on whether one or both sides of a print target are being printed upon, different drying units may be activated at different times. Thus, the drying component  310  may control at least some of the functions discussed above with respect to blocks  206  and  210  of the method  200 . 
     Furthermore, when a hardware processor executes instructions to perform “operations”, this could include the hardware processor performing the operations directly and/or facilitating, directing, or cooperating with another hardware device or component, e.g., a co-processor and the like, to perform the operations. 
     The processor executing the machine readable instructions relating to the above described method(s) can be perceived as a programmed processor or a specialized processor. As such, the present module  305  for printing on one or both sides of a web of print target, including associated data structures, of the present disclosure can be stored on a tangible or physical (broadly non-transitory) computer-readable storage device or medium, e.g., volatile memory, non-volatile memory, ROM memory, RAM memory, magnetic or optical drive, device or diskette and the like. More specifically, the computer-readable storage device may comprise any physical devices that provide the ability to store information such as data and/or instructions to be accessed by a processor or a computing device such as a computer or an application server. 
     It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, or variations therein may be subsequently made which are also intended to be encompassed by the following claims.