Patent Application
20140285559
Web-fed printing devices are commonplace and can be found, for example, in industrial or retail printing environments. Web-fed refers to the webs, or rolls, of media, being fed into the printing devices and are distinguishable from sheet-fed printers. Sheet-fed refers to individual sheets of media being fed into the printing device. The media can include paper, polymeric materials, or other media adapted for printing. Sheet-fed printing devices offer the advantages of being configurable for different format sizes and waste sheets can be reused for testing, which can lead to flexibility and lower cost print preparation. Web-fed printing devices, however, provide much faster printing than sheet-fed devices. The speed of web-fed printing devices makes them ideal for large runs such as newspapers, magazines, and books.
Web-fed printing devices can be used for offset, or analog, printing or for digital printing. Offset printing is a commonly used printing technique in which the inked image is transferred, or offset, from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat, or planographic, image carrier on which the image to be printed obtains ink from ink rollers while the non-printing area attracts a water-based film, or fountain solution, to keep the non-printing areas free from ink. Digital printing refers to methods of printing from a digital based image directly to the media. Digital printing can refer to professional printing where print jobs from desktop publishing and other digital sources are printed using large format or high volume laser or inkjet printers. In some circumstances, digital printing has a higher cost per page than more traditional offset printing, but the price is usually offset by the cost saving in avoiding steps to make printing plates. It also can more easily provide for on demand printing, short turn around, and even a modification of the image (variable data) with each impression.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.
Stand alone finishing modules, such as finishing module 106, are made to industry standards and are typically offered by third parties. Consequently, these finishing modules typically are not integrated with print engine 104 and operate via slack loop, i.e., where the media is fed to finishing module 106 without tension from print engine 104, or almost completely open loop. Generally, finishing module 106 is just set in place and aligned with the print engine 104. In a typical example, a dancer loop of the media in finishing module 106 is used to signal the finishing module to speed up or slow down based on the speed of the media fed from print engine 104. Additionally, print engine 104 provides start and stop signals to control the finishing module 106. Typically, finishing module 106 can operate at much higher speeds than the capabilities of print engine 104. In order to perform efficiently, finishing modules 106 receive the printed media from the print engine 104 in a form that is dry, stable, and flat with minimal distortion from media cockle and wrinkles. Accordingly, typical print engines 104 include closed loop controlled print zones for each side of the media, high-powered dryers, and active web steering mechanisms that continuously sense the position of the web and mechanically interact with the steering rollers to steer a web to a predetermined position.
Web-fed printing device 200 provides for passive steering and passive drying, which eliminates expensive corresponding components found in other web-fed printing devices. Passive steering implementations use a balance of forces to restrict the media to a predetermined path. Active steering devices, in contrast, continuously sense the position of the media and mechanically interact with the steering rollers to steer a web to a predetermined position. Active steering uses a mechanism to adjust the angle at which the media enters and leaves the roller that will adjust how the media moves along the axis of the roller. Active steering mechanisms may be expensive to build, add size and weight to the printer, difficult to implement without introducing aberrations into the print image, and complicated to control. Printers without passive drying, such as air-drying, employ high powered heaters and fans to dry the printing, which also adds costs to the printer and its use.
Print speed of the web-fed printing device 200 is affected by several factors, including print density, the physical length of the first and second drying regions 214, 226, respectively, the tension in the first and second print zones 210, 224, respectively, and the type of media 206 and printer ink (in the printer cartridges) being used. For any given combination of these factors, the optimum speed of the print engine 204 may not be the optimum speed of the sheeter 205.
The inputs 302 and 304 are applied and used to determine a beneficial tension of the media at 306. The inputs 302 and 304, and other factors such as the maximum speed of the print engine 204 and the maximum speed of the sheeter 205 or finisher are used as limiting factors to determine a beneficial print speed at 308. In the example, the physical length of the media stretched through the print engine 204 is used to determine the amount of passive drying applied to the media 206 after printing. In other examples, where the lengths are variable or the environmental conditions affect the passive drying, the lengths of the media and sensed environmental conditions, such as temperature and humidity, can be applied to determine tension 306 or speed 308.
The determined tension 306 and speed 308 are affected at 310. For example, the tension can be adjusted via the outfeed nip drive roller 228 distal to the second print zone 224. Speed can be adjusted through adjusting the number of rotations per unit time of rollers connected to a drive mechanism (not shown).
In one example, the beneficial tension 306 and speed 308 are determined through applying the parameters to look up tables. It should be noted that the amount of optimization could be dependent on the amount of characterization of the printing device performed to create the look up tables. If the operator of the printing device desires a wide variety of media 206, print densities, or ink and the overall speed of the printing device varies by a substantial amount, more characterization of the printing device may be performed. In one example where each printing device can be used to program or add characterizations to the look-up tables, the load cell roller 218 can be used to help characterize tensions in the print zones 210 and 224. The load cell roller 218 can then be left idle or removed for operation of the printing device.
The exemplary computer system includes a computing device, such as computing device 400. In a basic hardware configuration, computing device 400 typically includes a processor system having a processing unit, i.e., processors 402, and memory 404. By way of example, the processing units may include, but are not limited to, two or more processing cores on a chip or two or more processor chips. In some examples, the computing device can also have additional processing or specialized processors (not shown), such as a graphics processor for general-purpose computing on graphics processor units, to perform processing functions offloaded from the processor 402. The memory 404 may be arranged in a hierarchy and may include cache memory. Depending on the configuration and type of computing device, memory 404 may be volatile (such as random access memory (RAM)), non-volatile (such as read only memory (ROM), flash memory, etc.), or some combination of the two. Example computing devices 400 can take several forms. Such forms include a tablet, a personal computer, a workstation, a server, a handheld device, a consumer electronic device (such as a video game console), or other, and can be a stand-alone device or as part of a computer network, computer cluster, cloud services infrastructure, or other.
Computing device 400 can also have additional features or functionality. For example, computing device 400 may also include additional storage. Such storage may be removable and/or non-removable and can include, but is not limited to, magnetic or optical disks or solid-state memory, or flash storage devices such as removable storage 408 and non-removable storage 410. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any suitable method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Memory 404, removable storage 408 and non-removable storage 410 are all examples of computer storage media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, universal serial bus (USB) flash drive, flash memory card, or other flash storage devices, or any other storage medium that can be used to store the desired information and that can be accessed by computing device 400. Any such computer storage media may be part of computing device 400.
Computing device 400 often includes input and/or output connections, such as USB connections, display ports, proprietary connections, and others to connect to various devices to provide inputs and outputs to the computing device. Input devices 412 may include devices such as keyboard, pointing device (e.g., mouse), pen, voice input device, touch input device, or other. Output devices 411 may include devices such as a display, speakers, printer, or the like.
Computing device 400 often includes communication connections 414 that allow computing device 400 to communicate with other computers/applications 415. Example communication connections can include, but are not limited to, an Ethernet interface, a wireless interface, a bus interface, a storage area network interface, and a proprietary interface. The communication connections can be used to couple the computing device 400 to a computer network, which can be classified according to a wide variety of characteristics such as topology, connection method, and scale. A network is a collection of computing devices and possibly other devices interconnected by communications channels that facilitate communications and allows sharing of resources and information among interconnected devices. Examples of computer networks include a local area network, a wide area network, the Internet, or other network.
Computing device 400 can run an operating system software program and computer applications, which make up a system platform. A computer application to execute on the computing device 400 includes at least one process (or task), which is an executing program. Each process provides the resources to execute the program. Threads run in the context of the process. A thread is the basic unit to which an operating system allocates time in the processor 402. The thread is the entity within a process that can be scheduled for execution. Threads of a process can share its virtual address space and system resources. Each thread can include exception handlers, a scheduling priority, thread local storage, a thread identifier, and a thread context, or thread state, until the thread is scheduled. A thread context includes the thread's set of machine registers, the kernel stack, a thread environmental block, and a user stack in the address space of the process corresponding with the thread. Threads can communicate with each other during processing through techniques such as message passing.
An operation may execute in a thread separate from the main application thread. When an application calls methods to perform an operation, the application can continue executing on its thread while the method performs its task. Concurrent programming for shared-memory multiprocessors can include the ability for multiple threads to access the same data. The shared-memory model is the most commonly deployed method of multithread communication. Multiple threads execute on multiple processors, multiple processor cores, multiple logical nodes in a single processor core, and/or other classes of parallelism that are attached to a memory shared between the processors.
Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.
