Toyo Seikan Kaisha, Ltd.

Japan Crown Cork Co Ltd.

Masao Ishinabe

Katsuhiro Imazu

Akihiko Machii

Tomomi Kobayashi

Hisao Iwamoto

Hiroshi Ueno

Seishichi Kobayashi

Hiroshi Matsubayashi

Kiyoshi Kawaguchi

Hiroo Ikegami

Takashi Yazaki

Imazu Katsuhiro

Sumio Takeishi

Yutaka Okunishi

Atsuo Masaki

Disclosed is a process for making a preliminarily printed formed body, which is characterized in that a halftone separated rectangular printing plate is once made from a rectangular original, halftone dots of each halftone-separated image are developed on an annular plane by picture element units finer than the halftone dots to deform the shapes of the dots, an annular halftone dot image is formed based on the changes of the shapes of the halftone dots and a halftone printing plate for the annular halftone dot image is made, and this halftone printing plate is applied to a blank to be formed. According to this process undesirable formation of a striped pattern caused by the elongating flow of the blank in the height direction and the contracting flow of the blank in the circumferential direction is prevented and a strange feeling is not given to the printed image, and a faithful printed image can be reproduced.

Process for making preliminarily printed formed body

Process for the preparation of a draw-formed printed can

Disclosed is a method for preliminarily printing a blank for a tapered draw-formed body, which comprises transforming digital rectangular coordinates to annular coordinates so that the height of the rectangular coordinates is made to correspond to the height of a tapered plane on which the printed image is to be manifested and the change of the area of the tapered plane by a minute change of the height of the tapered plane is made equal to the change of the area of the annular plane. In this method, excessive flattening of the image in the lateral direction is prevented when the resulting preliminarily printed blank is draw-formed, and an image having a beautiful appearance and a high commercial value can be reproduced.

Method for preliminarily printing blank for tapered draw-formed body

Disclosed is a packing can having a circumferential polyhedral wall formed on a can barrel, in which as compared with boundary ridgelines of structural unit faces of the polyhedral wall and crossing points of these boundary ridgelines, the structural unit faces are convex to the interior of the can and the structural unit faces are arranged so that adjacent rows of structural unit faces have a phase difference in the axial direction of the can. This packing can has a very high strength against deformation by application of the external pressure. Furthermore, in preparing this packing can, damage of a coating layer formed on a metal sheet used as the can barrel blank can be effectively prevented.

Packing can

The present invention provides a redrawing method which comprises holding a preliminarily drawn cup of a covered metal sheet by an annular holding member inserted in the cup and a redrawing die, and relatively moving the redrawing die and a redrawing punch arranged coaxially with the holding member and redrawing cup, said drawing punch being capable of going into the holding member and coming out from the holding member, so that the redrawing die and redrawing punch are engaged with each other, to form a deep-drawn cup having a diameter smaller than that of the preliminarily drawn cup. This redrawing method is prominently characterized in that the radius of curvature of the operating corner portion of the redrawing die is 1 to 2.9 times as large as the bare sheet thickness of the metal sheet. According to this redrawing method, the thickness is effectively reduced by bending and elongating of the side wall, and the variation of the thickness between the upper and lower portions of the side wall is eliminated and the thickness is uniformly reduced as a whole.

Redrawing method and drawn-redrawn can

Plastic cap

The present invention provides a redrawing method which comprises holding a preliminarily drawn cup of a covered metal sheet by an annular holding member inserted in the cup and a redrawing die, and relatively moving the redrawing die and a redrawing punch arranged coaxially with the holding member and redrawing cup, the drawing punch being capable of going into the holding member and coming out from the holding member, so that the redrawing die and redrawing punch are engaged with each other, to form a deep-drawn cup having a diameter smaller than that of the preliminarily drawn cup. This redrawing method is prominently characterized in that the radius of curvature of the operating corner portion of the redrawing die is 1 to 2.9 times as large as the bare sheet thickness of the metal sheet. According to this redrawing method, the thickness is effectively reduced by bending anad elongating of the side wall, and the variation of the thickness between the upper and lower portions of the side wall is eliminated and the thickness is uniformly reduced as a whole.

Redrawing method

A process for the preparation of a printed draw-formed body having a printed image on the side wall thereof by subjecting a prior-printed blank to draw-forming, which comprises converting an image of an original to be printed to a digital image element signal on a rectangular coordinate, converting the image element signal on the rectangular coordinate to an image signal or image signals on a corresponding conversion coordinate formed by developing the rectangular coordinate to an annular plane having an area substantially equal to the area of said rectangle, reading image element signals on the conversion coordinate in order of the coordinate, photo-electrically converting the read image element signals to a printing plate for the blank and printing the blank by using the formed printing plate. According to this process, since digital coordinate conversion is performed while compensating anisotropy of the elongation of the metal blank, an improved printing precision can be obtained in a draw-formed body.

Process for printed draw-formed body, and container formed by this

Growing community of inventors

Atsugi, Japan

Masao Ishinabe