The previous post on wide-format printing technology provided an overview of roll-to-roll wide-format inkjet printers, including print-and-cut wide-format inkjet printers. This post discusses wide-format flatbed printers that can print directly on rigid materials and hybrid flatbed/roll-to-roll inkjet printers.
Wide-format flatbed printers have replaced the need to use large-format screen-printing presses to print graphics directly on 4 x 8 ft. sheets of foam board, coroplast, acrylic, metal, wood, and other sign and graphic materials.
When wide-format flatbed printers first hit the market around the year 2000, users of roll-to-roll wide-format printers could eliminate the extra production step of mounting self-adhesive flexible graphics onto the rigid sign and display boards. Some flatbed printers can hold irregularly shaped objects or heavy items that would be difficult to print directly with any other method.
Hybrid wide-format flatbed/roll-to-roll printers enable print shops with limited floor space to print graphics on both rigid sheets and flexible rolls of materials.
How Flatbed Inkjet Printers Work
Flatbed printers use vacuum tables to hold sheets of rigid or flexible materials in place while the ink is jetted from an industrial-grade printhead. These tables also keep substrates flat to maintain a consistent distance between the printheads and the substrate. Some vacuum tables have multiple print zones, so the system can print to different sizes of materials at once.
Some flatbed printers can vary the size of the ink droplets and produce high-quality images with fine details and smooth gradients between tones. Ink droplets can be placed in precise locations, even over images printed on other types of presses.
Most flatbed printers use “scanning” printheads that travel back and forth across the width of the printed sheet.
This video of Mimaki’s JFX500-2131 flatbed printer shows how variable-drop printing increases print quality and discusses the advantages of using UV-LED light to cure the inks. It also shows how the use of flatbed inkjet printing compares to the standard screen-printing process for large-format graphics printing. Video: Mimaki JFX500 UV LED Flatbed Printer.
On “bridge-type” flatbeds, the rigid sheets make multiple passes beneath a fixed array of printheads that spans the width of the print area. HP Scitex and Inca Onset flatbed printers are bridge type flatbed printers.
In this video about the HP Scitex 9000 flatbed printer, the sheet makes multiple passes beneath the fixed-array of printheads (above) that distribute inks across the width of the media (as seen below). (Video: HP Scitex | HP)
Hybrid Flatbed/Roll-to-Roll Printers can be equipped with roll-feed mechanisms that enable flexible materials to quickly be positioned beneath the moving printheads on the vacuum table.
This video shows EFI’s H1625 LED UV hybrid flatbed/roll-to-roll printer in action. This printer uses printheads made by Konica Minolta. (Video: Konica Minolta: EFI H1625 LED UV Wide Format Printer)
Types of Inks
Most flatbed and hybrid printers use piezo inkjet printheads with UV-curable inks, in which controlled intensities of UV light cause the droplets to “cure” into a thin film on the surface of the substrate.
UV-curable inks and clearcoats can be applied in layers to create dimensional effects, such as Braille letters, textured surfaces, or eye-catching details. For instance, a clear gloss varnish can form glistening water droplets that appear to pop-off the surface of an image of a rain-splashed window.
The HP Latex-R series of hybrid printers use thermal inkjet printheads and latex inks. These printers use heat instead of light to dry the inks. Because the dried latex inks don’t form an opaque film on the print surface, the natural grain of a wood substrate or luster of polished aluminum enhances the aesthetics of the print.
This video shows the HP Latex R series of printers in both flatbed and roll-to-roll print modes. (Video: Transform Almost Any Surface with HP’s Latex Rigid Printing)
Color Gamuts: Flatbed printers can apply multiple combinations of inks. The color gamut a printer can achieve depends on how many ink channels are used to apply different colors.
The chosen inkset varies depending on whether the machine will primarily be used for fast production of lower-cost outdoor graphics, high-quality photographic displays, or packaging materials that must match brand colors.
Photographic images achieve a higher level of image detail when light cyan and light magenta inks are added to the standard CMYK inks. Nine-channel Swiss Qprint flatbed printers can include orange, green, and violet inks to meet the wide range of spot colors used by brand marketers.
Some ink channels in the printhead deliver white ink, a clear varnish, or a primer to aid ink adhesion on films. White ink can provide a base layer for images that will be printed on non-white boards. Or, white ink can be used as a spot color. A white flood layer on clear film makes it possible to create graphics that can be backlit at night and bright and visible during the day.
Flatbed printers can print on the huge variety of materials used to make temporary and permanent signs, displays, and décorative products.
Depending on the ink chemistry and availability of inline primers, flatbed printers can print on acrylics, aluminum, aluminum composite materials, artboards, composite cardboard (such as Re-board), corrugated board, foamboard, MDF (medium density fiberboard) melamine, metal, particleboard, plastics, polycarbonate, fluted polypropylene (coroplast), PVC, styrene, and wood. Some flatbed printers, such as the HP Scitex FP series was specifically designed to print on a narrower range of sheets used to make folding cartons, cardboard boxes, indoor retail signs, and point-of-purchase displays. Other flatbeds use specialized UV-curable ink sets to print highway traffic signs or materials that can be processed into thermoformed plastic signs.
The Ricoh Pro T7210 flatbed printer for industrial decoration printing can print directly onto decorative glass, wood, steel panels, and bricks up 4.3 inches thick. (Video: Ricoh T7210)
The Roland VersaUV LEJ-640FT flatbed printers can print directly on heavy, rigid materials up to 6 inches thick and weighing up to 220 pounds.
Hybrid flatbed/roll-to-printers can not only print on rigid sign substrates, but also the flexible display films, synthetic papers, and adhesive vinyl used to make window graphics, posters, banners, labels, and decals.
Every flatbed, roll-to-roll, or hybrid wide-format inkjet printer is sold with a RIP (raster-image-processor). The RIP software converts data from the design files into the layout, resolution, color, and print mode data that each different printer needs to eject the ink droplets with the proper timing, sequence, and screening patterns.
To reduce the need for operators to set up jobs at each printer, production wide-format RIP software from Onyx Graphics, Caldera, ColorGate, Ergosoft and Wasatch can coordinate print production on the multiple brands of roll-to-roll and flatbed wide-format inkjet printers, digital cutters, and color measurement devices that might be used within a single print shop. .
Today, many large-format RIPs use the Adobe PDF Print Engine (APPE) to help convert the design files to print data. This enables wide-format inkjet printing workflows to be more like the PDF-based prepress workflows commonly used in commercial offset and production inkjet printing.
Like scanning flatbed printers that carry printheads across the surface of the media, flatbed cutters use moving carriages with different sets of tools to crease, score, engrave, and straight-cut or contour-cut different types and thickness of prints. Flatbed cutters also use vacuum tables to align and hold the printed materials in place.
Esko’s Kongsberg series of flatbed cutters can be used to cut rigid and flexible materials into high-volume of smaller prints, such as square or oval labels (above) or cut-out images for stand-up displays or signs. (Video: The Kongsberg Cutting Table as Game Changer)
Depending on which tool units and materials are used, a cutting table can be used to make the creases, holes, contour cuts, or engravings need to convert the printed substrate in a sellable product. For example, a cutting table can be used to:
- Create ready-to-fold boxes and cartons
- Make free-standing point-of-purchase displays and trade-show booths
- Contour-cut labels and decals
- Cut fabrics, canvas, and mesh materials for banners, décor, and apparel
- Make smaller promotional products such as coasters
- Engrave acrylic for signs and decor
- Carve (“route”) designs in wood panels
- Add braille lettering to signs and displays
When files are set up for printing on a sheet or roll of wide-format material, the software can also send cutting instructions for the printed graphics directly to the automated cutter.
Advances in Technology
The total cost of operating flatbed printers is going down, thanks to advanced technologies that reduce energy consumption, improve print speeds, automated material handling, and minimize ink usage.
This video shows the automated sheet-loading and unloading system used with the Inca Onset series of flatbed printers. (Video: Inca Onset Full Automation for Display Graphics)
Flatbed inkjet printers with LED-curing systems use significantly less energy than first-generation UV flatbed printers that used mercury-vapor lamp systems originally developed for screen-printing presses that used UV-curable inks.
To boost throughput speeds. Inca Digital has just announced a high-speed “single-cycle” mode for their Onset X flatbed printers.
As commercial print firms diversify into wide-format printing, they want unified, automated workflows that can simplify prepress, pre-flighting, color management, proofing, scheduling, job costing, and production oversight on different combinations of offset and flexo presses, production inkjet printers, roll-to-roll, and flatbed wide-format inkjet printers, and finishing devices. Software from companies such as Agfa (Apogee and Asanti), Kodak (Prinergy), and Esko (Automation Engine) can help accomplish these goals.
Innovations such as the PrintFactory Super RIP software from GMG Color can help users of multiple types of wide-format inkjet printers streamline the production of color-consistent materials. Print Factory automatically adjust the color in the print files based on which printing process, inkjets, and materials will be used for each element of a multi-part job.
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This post is part of a series we are publishing to help you understand the many types of analog and digital printing processes now in use.
Follow Ordant on LinkedIn, Facebook, or Twitter to learn when the next post in this series has been published. Our next post will discuss grand-format inkjet printers.
Digital Press Technology-Part 1: Electrophotography
Digital Press Technology - Part 2: Production Inkjet Printing
What is offset printing?
What is Screen Printing?
What is Flexographic Printing?