Printing apparatus for producing liquid crystal devices

Abstract: In a printing apparatus having a blade-form ink extender and an ink extension member for extending an ink thereon in association with the ink extender, there is provided a means for removing an excess of the ink from the ink extender and/or and the ink extension member. The printing apparatus is suitably used for forming a film of an organic polymer or an inorganic oxide in a process for production of a liquid crystal device.

Description: The present invention relates to a transfer printing apparatus according to the preamble of claim 1. In recent years, a flexographic apparatus has been introduced in a patterned film forming step in a liquid crystal cell production process, and the applicability thereof to a wide scope of materials has called attention. For example, the utilization of a flexographic apparatus has been considered, first for application of an alignment material, such as polyimide, and also for application of an insulating material to be formed by sintering, a sealing material and various resists. The advantages accompanying the use of a flexographic apparatus, e.g., when used in production of liquid crystal cells, may include: (1) a decrease in production cost due to omission of a patterning step, (2) an improvement in product performance due to removal of adverse effects accompanying the use of a resist and a patterning step, (3) a reduction of an equipment cost and an increase in throughput compared with the case of using a film-forming apparatus, (4) an improved performance due to protection of a print surface compared with the case of using the screen printing. Thus, the advantages are extensive and remarkable including improvements in liquid crystal cell performances, decrease in production cost and enhanced productivity. The document GB-A-1 525 805 discloses a generic transfer printing apparatus, according to the preamble of claim 1. This apparatus comprises a projecting extender in the form of a blade, an extension member for extending an ink thereon in association with the projecting extender, a printing plate for taking up said extended ink and transferring said ink to a substrate to be printed, and also a removal blade for an excess of the ink after extension from the extension member. The removal blade is set at an angle larger than 90° with respect to the extension member in the direction of transfer. Accordingly, the excessive ink is removed from the surface of the extension member roller and drained off in a direction away from the extension member. According to document DE-C-282 786 there is known a removal means by which the excessive ink is removed from a printing plate by suction. The further document GB-A-2 043 537 describes a plate for scraping any remaining ink from the surface of a transfer plate in a post-printing treatment. A principal object of the present invention is to provide a transfer printing apparatus capable of being applied to a wider scope of inks having a wider viscosity range. This object is achieved by means of the combination of the features defined in claim 1. Preferable embodiments of the invention are recited in the subclaims. The transfer printing apparatus according to the present invention may particularly suitably be used for applying a solution containing an organic polymer or an inorganic oxide precursor. Hereinbelow, some preferred embodiments of the present invention will be described with reference to the drawings. Figures 1C - 1C are side views for illustrating the extending and ink-removing actions of an extension roller in a flexographic apparatus according to an embodiment of the present invention. Figure 2 is a perspective view of the extension roller in Figure 1. Figure 3 is a perspective view of another extension roller usable in the apparatus of Figure 1. Figure 4 is a side view for illustrating a printing operation of a printing mechanism used in a conventional flexographic apparatus. Figures 1A - 1C illustrate a structure and an action of a printing mechanism, particularly an extension mechanism, in a flexographic apparatus according to an embodiment of the present invention. Referring to these figures, the mechanism includes a doctor blade 1 and an extension roller 2 equipped with a groove 2a, and is suitably used in a printing apparatus of the type using an extension roller as shown in Figure 4. According to the mechanism shown in Figure 4, an ink is extended on an extension roller 2 of a metal by a blade-form extender member, such as a doctor blade 1, and the extended ink is taken up by a printing plate 5 of a rubber fastened to a cylinder roller 4 and transferred to a rigid substrate to be printed, such as a glass plate 6 supported on a movable stage 7. An excessive amount of the ink on the extension roller 2 is removed by the extender blade and received by an ink-receiving pan. The printed film thickness is principally controlled by the viscosity of the ink and the rate of opening and depth of a fine groove pattern formed on the extension roller 2. As shown in Figures 1A - 1C, the extension roller 2 is provided with a groove 2a for removing an excess of ink 3a remaining on the doctor blade 1. More specifically, an ink 3 is extended on the extension roller 2 by the doctor blade 1 (Figure 1A), and an excess 3a of the ink remaining at the tip of the doctor blade is caused to fall in the groove 2a (Figure 1B) and further scraped off by the edge of the groove 2a (Figure 1C). As a result, it has been confirmed that inks with a broader range of viscosity can be extended and applied without causing extension irregularity, and a continuous running time is remarkably prolonged by suppressing a viscosity increase of the ink left attached to the tip of the doctor blade 1. In this instance, the groove 2a of the extension roller 2 can be formed in parallel with the rotation axis of the roller 2 as shown in Figure 3 but may preferably be formed obliquely with respect to the rotation axis of the roller 2 as shown in Figure 2 in view of the ink-scraping effect and the protection of the doctor blade 1. As described hereinabove, according to the present invention, a means for removing an excess of ink from an ink-extender member and an ink extension member is provided, whereby a transfer printing apparatus has become applicable to a wider scope of materials or inks having a broader viscosity range, thus resulting in an enhanced productivity. The transfer printing apparatus is suitably used for forming a film of an organic polymer or an inorganic oxide in a process for production of a liquid crystal device.

Claims: A transfer printing apparatus, comprising: a projecting extender (1) for extending ink (3) on an extension roller (2), a printing plate (5) for taking up said extended ink (3) and transferring said ink (3) to a substrate (6) to be printed, characterized by removal means for removing an excess (3a) of said ink (3) after the extension of ink on said extension roller (2), said removal means being a groove (2a) provided in the surface of said extension roller (2). An apparatus according to claim 1, wherein said groove (2a) is formed obliquely with respect to the rotation axis of said extension roller (2). An apparatus according to Claim 1, wherein the apparatus is adapted to produce a patterned film on a liquid crystal cell substrate. An apparatus according to Claim 1, wherein the ink comprises a solution for forming an organic polymer film. An apparatus according to Claim 1, wherein the ink comprises a solution for forming an inorganic oxide film.

Inventors: DANJO KEISHI, WATANABE YASUYUKI, YOSHIOKA TOSHIFUMI, DANJO, KEISHI, WATANABE, YASUYUKI, YOSHIOKA, TOSHIFUMI, Danjo, Keishi, c/o Canon Kabushiki Kaisha, Watanabe, Yasuyuki, c/o Canon Kabushiki Kaisha, YOSHIOKA, TOSHIFUMI, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1992
Main classification: B41F5
IPC codes: B41M1, G02F1, B41F5, B41F35, B41F9, B41N10, B41M3, B41F17