Roplast Industries is a wide web flexographic, surface printer. Flexography is a direct printing method that uses relief plates, similar to rubber stamps that are made from rubber or photopolymer with raised images. The ability to reproduce fine lines, screens and halftones is limited compared to lithography, gravure and narrow web flexography.
Roplast's bags are manufactured from linear low density, low density and medium density polyethylene film blends. In addition to white, Roplast offers many custom colors. Film finishes include gloss, matte, frosted, and pearlescent. The type of film blend and color selected affects the quality of the print lay-down, final ink densities and overprint colors (particularly process work and/or continuous tone artwork).
Note on Film Specifications: Please refer to the Roplast Film flier for more detailed information pertaining to color, density and other capabilities.
Roplast prints line screens-the measure of lines or dots per inch on a halftone screen-of solid colors and process work at 65 lpi, 85 lpi, 110 lpi or 120 lpi. The finer the screen used to create the printing negatives and plates, the more detail can be portrayed in the final printed piece. To reproduce a screen accurately, it may be required to print the solid of the same color on a separate print deck.
Line screens vary depending on printing press capability and specialty film characteristics. Please call your Roplast Sales Service Representative or Roplast Art Coordinator for specific guidelines.
Roplast’s high quality multi-color printing ranges from:
- up to 120 lpi: one to six colors/two sides
- up to 65 lpi: one to eight colors/two sides in various combinations not totaling more than eight colors (i.e. 6-side A, 2-side B).
In order to allow normal register tolerances to exist without degrading the integrity of a design, trap is required between adjacent images printing in different colors. Please supply untrapped art files (Roplast will
apply trap.) that have been designed to accommodate our trap tolerances. For the majority of Roplast products, our presses require a trap of 1/32" (0.0313) minimum to 1/16"(0.0625) maximum.
Trap tolerances vary depending on individual printing press capability. Please call your Roplast Sales Service Representative or Roplast Art Coordinator for specific guidelines on your project.
Roplast prefers that customers do not supply platemaking negatives. If this can't be avoided, negatives may be submitted for artwork containing line work only, unless the pre-press vendor making the film has “fingerprinted" our presses to determine a cut-back curve. Negatives must he right reading (RR) and emulsion side up (NEU) for surface printing. Film must be free of kinks and packaged appropriately to avoid scratches during transportation to Roplast.
It is also preferred that plates are not customer supplied. If this cannot he avoided, plates may be submitted for artwork containing line work only, unless the pre-press vendor making the plates has "fingerprinted" our presses to determine a cut-back curve. Printing plates must be 100% across the press width and distorted in the machine direction to compensate for cupping. Roplast uses a photopolymer plate thickness of 0.067" and we prefer Cyrel® EXL material over other brands. The plate thickness for rubber plates is 0.107”. Natural rubber is preferred over synthetic and PVC. Identify customer or job name and color on each plate.
Customers may visit our facility on the day(s) artwork is scheduled to print. Customer attendance is welcome, but not mandatory, unless otherwise requested by a Roplast Sales Service Representative due to a complicated design. Additionally, if you wish to visit Roplast for a press check, please inform your Roplast Sales Service Representative so they can schedule the necessary components of the visit.