It is not too much to say that screen printing has been along with the development of electronics industry. Screen printing has to correspond with the higher efficiency and micronization of IC or LSI. Now higher precision and density in screen printing are strictly required and the precision has to be even less than 100 micron meters which brought up the shift to photographic process in this field. But in view of mass production screen printing has such advantage that it will promise to take an important part among electronics materials in future. Therefore we should not spare effort to develope specific technology not limited in the version or extention of the techniques we already have.

View full abstract

Screen printers are now employed frequently as a part of production facilities for electronic units or devices. As electronic components become lighter, thinner, shorter, and smaller, screen printers of higher accuracy and higher performance are required irrespective of whether their application processes are upstream or downstream. Under these circumferences, users' greatest concern lies in the stability of production or mass-printing of fine patterns. This paper describes the following items about new functions and devices of the screen printers as a means of solving the problem. 1. An automatic positioning device with an image recognition function (Vision system). 2. Automatic situation of printing conditions. 3. A device of increasing printing shots for improving the continuity in printing. 4. An introduction to an R & D printer (Newlong). 5. Ending

View full abstract

Composition and properties of screen printing inks for print circuit board are outlined. Continuous progress of semiconductor technology required high density circuit with high resolution and reliability on the board. The role of screen resist inks, properties of ink films and importance of rheology of ink and printing process are described.

View full abstract

Laser direct plate making system in the field of screen printing is very attractive. In this system, circuit pattern created with CAD was directly plotted on PS plate for screen printing by using an argon ion laser light. This system have a lot of advantages such as a shortening of process time, because it is not necessary to make a positive film in the process. Development of a high sensitive PS plate is expected to realize the film-less plate making system. Laser direct exposure system was found in some reports to expose a dry film photoresist or photoresist. There are few report about laser sensitive material in screen printing. We developed a highly sensitive photopolymer for argon ion laser exposure (488nm). The photopolymer has a same quality as a conventional screen printing plate.

View full abstract

Recent advances in fine pattern fabrication by screen printing are described. Screen printer equipped with optically automated alinement apparatus of substrate can result in the accuracy of within ±15μm. A screen mask with wide-weave opening and a paste with high thixotropic characteristics make it possible to fabricate a fine pattern less than 30μm W & S.

View full abstract

The ink transfer and splitting in a roll nip are investigated in connection with characteristics of rollers and blankets. Modified rolling cylinder tackmeter with precise position and stress sensors was used to determine the pressure profile in the thin ink film during passage through a roller nip. IGT printability tester, type AIC2 was used for pick test. Pick-resistance was evaluated with the velocity at the beginning of picking in the test at increasing velocity mode. In the region of around nip center, the pressure drops monotonically from a maximum at the beginning of shear region to a minimum where cavitation occurs. The pressure profile can be predicted by Gaskell's equation, qualitatively. The effect of viscoelasticity of printing inks on ink splitting becomes more pronounced using a roller of which surface is more elastic and a good affinity for ink. Blanket with smooth surface tends to cause picking and peeling because higher negative pressure arises at the end of shear region. When blanket with higher compressibility is used, picking is reduced because flexibility of intermediate sponge layer of blanket releases the distortion of surface rubber layer of blanket which causes an irregular fours between paper surface and blanket one. However the amount of ink transferred from higher compressibility blanket is less comparing with that from more rigid blanket. Ink transfer and penetration were monitored by image analyzing system based on the reflection density of the reversed side of the printed paper.

View full abstract

In this paper, fundamentals of mathematics for image analysis is described. Firstly, mathematical definition and physical meanings of some singularity functions such as delta function and rectangular function used in the image analysis are described. Secondly, Point Spread Function (PSF) and Line Spread function (LSF) are defined, and convolution integral and convolution theorem of Fourier Transform are introduced. Finally, image processing results by Gaussian filter are shown.

View full abstract

This paper deals the situation of graphic arts in hardcopy technologies and the fundamental problems in offset printing process on machine. It is emphasized that the basic ideas for comprehending offset printing process are in view of a ink transfer mechanism and a transfered ink amount and its shape of dots on paper.

View full abstract