Browse Prior Art Database

Copier Diffuser

IP.com Disclosure Number: IPCOM000052197D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Louis, HP: AUTHOR [+2]

Abstract

During copying on office copiers with good grey tone reproduction, such as IBM Copier III, the reproduction of high gloss or metallic, reflecting masters shows grey clouds in the background of the image. These clouds, resulting from localized overexposure or underexposure caused by the gloss of the master and the positioning of the light source, are eliminated by special diffusers 1 which are placed on glass plate 2 of the copier.

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Copier Diffuser

During copying on office copiers with good grey tone reproduction, such as IBM Copier III, the reproduction of high gloss or metallic, reflecting masters shows grey clouds in the background of the image. These clouds, resulting from localized overexposure or underexposure caused by the gloss of the master and the positioning of the light source, are eliminated by special diffusers 1 which are placed on glass plate 2 of the copier.

Fig. 1 is a schematic diagram of a first embodiment, according to which a glass diffuser 3 with a roughened surface 4 on one side is used on glass plate 2. Glass diffuser 3 has a thickness of about 2 to 3 mm and is roughened to the desired value by glass-to-glass grinding with a wet glass grinding powder. The smooth surface of glass diffuser 3 rests directly on glass plate 2 of the copier. Master 5 is placed on the roughened surface 4 and pressed closely against glass diffuser 3 by means of a plate 6 comprising, if necessary, a foam layer 7. Thus, the light is scattered at the roughened surface 4 in the immediate vicinity of the master surface, while the reproduction of the desired contents of the master is not noticeably affected.

Fig. 2 shows a foil diffuser 8, in place of the glass diffuser 3, which is about 35 Mum thick and which is roughened on one side in the same manner as glass diffuser 3. Whether the roughened side of the foil faces the glass plate 3 or the master is not important.

It is also possible to use a f...