Gocco (プリントゴッコ, Purinto Gokko, "Print Gocco") is a self-contained compact color printing system invented in 1977 by Noboru Hayama. Gocco became immensely popular in Japan and it is estimated that one-third of Japanese households own a Print Gocco system. The printing mechanism is that of screen printing. The Gocco sets included the materials and tools to both make the screens, and to use these screens for printing. As the Gocco screens are quite small, they were most widely used for printing greeting cards, a popular need within Japanese culture. Gocco could also print to fabrics, although only across a small area. The Gocco printing screens did offer good registration, so two or more colour printing was practical and popular.
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The name "print gocco" is derived from the Japanese word gokko (ごっこ), loosely translated as make-believe play. Riso Kagaku president Noboru Hayama explained, "We [as kids] learned rules and knowledge through make-believe play. The spirit of play is an important cultural asset. I thought that I wanted to leave "play" in the product's name."
Printing method
The Gocco process was scaled down, but otherwise very similar to large commercial screen printing techniques. The equipment included simple plastic holders for screen making and printing.
Screen printing uses a mesh screen that is coated with an impermeable paint-like material to make a stencil of the design. The ink can pass through the bare mesh, but is stopped by the impermeable stencil material. These screens are made by the printer before use, either by painting the stencil material only where it is needed or more commonly, as with the Gocco, by a simple photographic process.
Screen making
Artwork was prepared as a simple black and white illustration on paper. This could be done by hand, with ink, paint or pencil, or by computer printing (although the original Gocco pre-dated home computer printing). A translucent lightweight paper and a solidly opaque illustration gave better results and sharper prints. It was also possible to use photograms, using a natural material such as a leaf as an artwork of found-materials.
The raw screen was first coated overall with a stencil material. This was then sandwiched with the artwork and the Gocco's simple battery-powered lightbox was used to expose the screen. This used flash bulbs similar to those found in old cameras. The exposed screen could then be developed to wash away the unexposed areas (i.e. those shielded by the artwork), producing a stencil screen.
Where multiple colours were to be printed, a separate screen was made for each colour.
Gocco screens could be used repeatedly. The original patent cites a potential lifetime of 2000 prints, although few Gocco users were interested in such volumes. If cleaned of ink after printing, a screen could also be stored for future printing.
Used screens could be washed clean of the stencil afterwards, re-coated and re-used with new designs.
Printing
Printing was as for conventional screen printing. The screen and the paper to be printed were sandwiched in the Gocco printing frame. A squeegee was then used to work a viscous ink around the screen, passing through the mesh in the bare parts of the stencil and onto the paper.
Decline
In December 2005, Gocco’s parent company, Riso Kagaku Corporation, announced it would end production of the Gocco system due to low sales in Japan. An Internet campaign was started to find a new home for the product.
As of June 2007, Riso Kagaku Corporation had resumed production of several lines of Print Gocco units and they were available in Japan and through limited import retail stores in the United States.
On May 30, 2008, the Riso Kagaku Corporation announced that it would stop shipping Gocco printers in June 2008. It blamed the sharp decline in demand for its printers on the increase in use of home computers and printers. It was to continue producing supplies for the printers.