Printing – Inkers
Reexamination Certificate
2003-05-06
2004-11-02
Hirshfeld, Andrew H. (Department: 2854)
Printing
Inkers
C101S116000, C101S119000, C101S364000, C101S366000, C222S386000
Reexamination Certificate
active
06810803
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a stencil printing ink container, which is capable of being releasably fitted to a stencil printing apparatus in order to furnish ink to the stencil printing apparatus.
2. Description of the Related Art
Stencil printing apparatuses for performing printing operations by use of thermosensible stencil paper have heretofore been known. With the stencil printing apparatuses, a thermal head comprising fine heating elements arrayed in a line is brought into contact with stencil paper, and the stencil paper is conveyed by a platen roller, or the like, while the heating elements are being energized. In this manner, a perforation image in accordance with image information is formed on the stencil paper. Thereafter, the stencil paper, on which the perforation image has been formed, is wound around a printing drum. Also, printing paper is pushed by a pushing member, such as a press roller, against an outer circumferential surface of the drum and moved. In this manner, ink is oozed out through an opening area of the drum and perforations of the stencil paper and transferred onto the printing paper. A printed image is thus formed on the printing paper.
In order to cope with reduction in diameter of plate making perforations of the stencil paper for obtaining a precise printed image, or in order to enhance the printing speed by enhancing infiltrating characteristics of the ink into the printing paper, it is often desired that a viscosity of the ink used be set at a low viscosity. In particular, in cases where the ink viscosity with respect to a region of a shear rate of at most 100 sec
−1
is set at a low viscosity, the ink having been transferred onto the printing paper is capable of quickly infiltrating into the printing paper, and printed paper free from an ink offset to the back of the paper is capable of being obtained.
Conventional ink furnishing means of the stencil printing apparatuses comprises an ink furnishing roller, a distributor, and a doctor roller. The ink furnishing roller is located within the printing drum and is supported between side plates which stand facing each other. The ink furnishing roller is capable of rotating around its center axis. The distributor is located on the ink furnishing roller and supplies the ink onto the ink furnishing roller. The doctor roller is located at a predetermined spacing from the ink furnishing roller and controls the thickness of an ink film, which is formed around the outer circumferential surface of the ink furnishing roller. An example of the distributor comprises parallel tubular members having a plurality of holes having a small diameter. A different example of the distributor comprises a plurality of nozzles. The ink is sucked by an ink pump from an ink container and supplied dropwise through the distributor onto the ink furnishing roller. An ink accumulating area is formed at a wedge-shaped region between the ink furnishing roller and the doctor roller. The ink is furnished through a space between the ink furnishing roller and the doctor roller into the printing drum. Such that the ink may be furnished uniformly, a predetermined amount of the ink is always held at the ink accumulating area.
Ordinarily, a W/O type of emulsion ink comprising 10 wt % to 50 wt % of an oil phase and 90 wt % to 50 wt % of an aqueous phase is utilized for the stencil printing apparatuses. In cases where the stencil printing apparatuses are left to stand for a long period of time instead of being used for the printing, since the ink accumulated at the ink accumulating area is exposed to air, water contained in the ink is vaporized, and a pigment concentration in the ink becomes high. Therefore, the ink having a low viscosity remains at the ink accumulating area. In cases where fresh ink is furnished to the ink accumulating area, the remaining ink and the fresh ink cannot easily mix with each other, and therefore it often occurs that nonuniformity in image density occurs on the printed paper. Nonuniformity in image density occurs markedly in the cases of ink, which has a comparatively high viscosity with respect to the region of the shear rate of at most 100 sec
−1
.
As an example of an ink container utilized for the stencil printing apparatuses, there has heretofore been known an ink container (a BIC type of an ink container) comprising an outside casing formed from a corrugated board, or the like, and a flexible inside bag accommodated within the outside casing. An ink injecting tube, which is formed at an end of the inside bag, is projected from the region within the outside casing to the exterior of the outside casing, and the projected end of the ink injecting tube is closed with a cap. Also, as a different example of an ink container utilized for the stencil printing apparatuses, there has heretofore been known an ink container (a piston type of an ink container) comprising a cylinder, which has a circular cylinder-like shape and is provided with an ink discharge opening section at an end, and a piston, which is located within the cylinder. In particular, the piston type of the ink container has the advantages in that the amount of the ink, which remains within the ink container after the ink suction has been performed until ink suction and furnishing cannot be conducted any more, is smaller than 8 the amount of the remaining ink in the cases of the BIC type of the ink container, and therefore the ink is capable of being used efficiently. The ink discharge opening section of the piston type of the ink container is sealed by a thread type of cap. When the piston type of the ink container is to be used, the user removes the cap from the ink discharge opening section, inserts the ink container through a container holder on the side of the main body of the stencil printing apparatus, and fits the ink discharge opening section of the ink container to an ink suction opening section on the side of the main body of the stencil printing apparatus. In this manner, the piston type of the ink container is used.
However, with the conventional piston type of the ink container, it is considered that the problems described below occurs in cases where the ink container is filled with ink having a comparatively low viscosity with respect to the region of the low shear rate described above and used. Specifically, in cases where the user removes the cap from the ink discharge opening section of the ink container and holds the ink container with the ink discharge opening section facing down, the ink drips down from the ink discharge opening section of the ink container and soils the hands or clothes of the user, the region within the stencil printing apparatus, a floor surface within a room in which the stencil printing apparatus is located, or the like.
In order for the problems described above to be solved, a structure, in which a valve opened through engagement with a main body of a printing machine is located within an ink discharge opening section of an ink container, has been proposed in, for example, Japanese Unexamined Patent Publication No. 2000-318288. However, the proposed ink container has the problems in that the valve located within the ink discharge opening section of the ink container is constituted of a fine member and therefore has a strong probability of being broken, and in that the cost cannot be kept low due to the increased number of parts.
Also, a method of setting an ink container, wherein an ink container is set in a main body of a printing machine with an ink discharge opening section of the ink container facing up, such that a user may not locate the ink container with the ink discharge opening section facing down in a state in which the ink discharge opening section is released, has been proposed in, for example, Japanese Unexamined Patent Publication No. 2000-272097. However, with the proposed method of setting an ink container, limitation is imposed upon the size of the ink container which is capable of being utilized. However, stencil printing app
Arai Masakatsu
Hashimoto Hirohide
Oshio Kenichi
Ferguson Marissa
Hirshfeld Andrew H.
Nixon & Peabody LLP
Riso Kagaku Corporation
Studebaker Donald R.
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