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A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as inkjet, but xerography is standard for office copying. Commercial xerographic office photocopying and it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines. Photocopying is widely used in the business, education, and government sectors. While there have been predictions that photocopiers will eventually become obsolete as inform

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TIP: Tangible e-Ink Paper Manipulatives for Classroom Orchestration

Wafa Monia Benkaouar Johal, Pierre Dillenbourg, Hala Khodr, Ayberk Özgür

While digital tools are more and more used in classrooms, teachers' common practice remains to use photocopied paper documents to share and collect learning exercises from their students. With the Tangible e-Ink Paper (TIP) system, we aim to explore the use of tangible manipulatives interacting with paper sheets as a bridge between digital and paper traces of learning. Featuring an e-Ink display, a paper-based localisation system and a wireless connection, TIPs are envisioned to be used as a versatile tool across various curriculum activities. In this paper, we present the design principles of TIPs and a first functional prototype. We conclude by presenting future works in the evaluation of TIPs as a distributed sensor for teachers in their classroom, including learning scenario examples to illustrate our statements.

ACM2019

Reproduction of security documents and color images with metallic inks

Patrick Emmel, Roger Hersch

The present invention discloses methods and systems for printing by superposing a metallic ink and transparent inks. These methods and systems are useful for color separating images into superpositions of a metallic ink and transparent inks both for design purposes and for the creation and authentication of security documents, such as banknotes, checks, diploma, corporate documents, passports, identity cards, credit cards, product labels, optical disks, CDs, DVDs, packages of medical drugs, cosmetics, and alcoholic drink bottles. By combining a metallic ink and transparent inks, one may create printed images behaving dynamically: an image viewed under specular reflection may be considerably different from the same image viewed under non-specular reflection. Patterns which are either dark or hidden become highlighted under specular reflection, yielding interesting visual effects. Metallic inks allow therefore to create visually appealing dynamically changing color images. In addition, the inversion effect provided by metallic inks allows to enhance microstructures present in the image or to reveal hidden patterns. Since these effects are lost in photocopied documents, the disclosed methods, systems and security documents offer a high security against counterfeiting attempts.

2004

Method and apparatus for generating halftone images by evolutionary screen dot contours

Roger Hersch

The present invention is related to the synthesis, display and printing of halftone images. The invention comprises a method capable of generating screen elements with sophisticated screen dot shapes such as artistic shapes, microletters and ideograms. The method can be used to generate screen elements whose screen dots are made of evolving artistic shapes at increasing intensity level. For generating screen elements at consecutive intensity levels, intermediate contours which bound the white and black parts of each screen element are obtained by interpolating between fixed predefined contours. Such interpolated contours defining screen dots may be transformed from a screen dot definition space to a screen dot rendition space before being converted into discrete screen elements by a scan conversion and filling operation. Since the method allows producing large screen elements made up of many distinct subscreen dot shapes, the process can be used to generate discrete subscreen elements whose geometry may vary from one subscreen dot to another for the same intensity level. Some subscreen dot shape variations may be used to avoid counterfeiting by photocopying machines and digital scanners. The contours which make up the screen elements' dot shapes may be of arbitrary complexity. This characteristic makes the invented process useful in fields where halftoning with sophisticated screen dot shapes is desired, i.e. for printing banknotes, postage stamps or valuable papers. Screen dot shapes made of latin, greek cyrillic or arabic typographic characters as well as screen dot shapes made of ideograms offer new design freedom for creating posters and graphic designs.

2004

Laser printing

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a ne

Printer (computing)

In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an e

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Inkjet printing is a type of computer printing that recreates a by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 200

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This course provides the fundamental knowledge and theoretical tools needed to treat nonlinear optical interactions, covering both classical and quantum theory of nonlinear optics. It presents applications such as nonclassical state generation and coherent frequency conversion.

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AR-219: Advanced CAO and Integrated Modeling DIM

1ère année: bases nécessaires à la représentation informatique 2D (3D). Passage d'un à plusieurs logiciels: compétence de choisir les outils adéquats en 2D et en 3D. Mise en relation des outils de CAO et DIM: regard critique et aptitude à choisir les méthodes nécessaires au résultat recherché.