Printing – Stenciling – Rotary machines
Reexamination Certificate
1999-12-23
2001-02-27
Yan, Ren (Department: 2854)
Printing
Stenciling
Rotary machines
C101S248000, C101SDIG029
Reexamination Certificate
active
06192793
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drum type printer, and more particularly, to a drum type printer having a mechanism for adjusting a transverse position of a printed image.
2. Description of the Prior Art
In Japanese Patent Publication No. 2542489 issued Oct. 9, 1996, there is described a device for adjusting a transverse position of a printed image for a stencil printer having a drum unit rotatably supporting a cylindrical printing drum and slidably mounted in a body of the printer along the longitudinal axis of the printing drum, so as to be manually dismountable out of the printer body at the end of the sliding drawout movement, wherein the printed image transverse position adjustment device comprises guide means provided in the printer body for guiding the drum unit in the sliding direction, a movement transmission system for moving the drum unit in the sliding direction along the guide means for a minute distance, a motor for driving the movement transmission system, and clutch means for optionally connecting or disconnecting the movement transmission system to or from the drum unit.
In the printed image transverse position adjustment device for a stencil printer described in the above-mentioned patent publication, the drum unit is slid as a whole for an adjustment of a transverse position of a printed image along the guide means for dismountably mounting the drum unit in the printer body.
The drum unit of this type, when it is the drum unit of a stencil printer, incorporates therein an ink container to serve as a source of a printing ink and an ink pump for transporting the ink from the ink container to the inside of the printing drum, so that the weight of the drum unit as a whole is substantial such as about 10 kg or more. Further, such a drum unit has a length such as about 40 cm or more and a diameter such as about 20 cm. Therefore, for the drum unit of such weight and size to be inserted into a drum unit bore of the printer body or drawn out of the drum unit bore by the hands of a man or woman, what is required for the guide means for guiding the drum unit relative to the printer body for the insertion and the drawout thereof into and out of the printer body is a strength rather than a fineness.
On the other hand, an adjustment of a transverse position of a printed image provided on a print sheet is of the order of 10 mm at the largest, and often requires a fineness smaller than 1 mm, so as to be more desirable as the fineness is higher.
In view of the above points, it will not be rational to conduct such an adjustment of a transverse position of a printed image that is in a range of 10 mm at the largest and is more desirable when it is more fine, by such macro-structural guide means for guiding the drum unit, a heavy article, over a guide distance extending so long as about 40 cm for the insertion and the drawout thereof into and out of the printer body.
SUMMARY OF THE INVENTION
In view of the above matters, it is a primary object of the present invention to provide a drum type printer equipped with a device for adjusting a transverse position of a printed image suitable for the purpose of adjusting a transverse position of a printed image and the performance required therefor.
According to the present invention, the above-mentioned primary object is accomplished by a drum type printer comprising:
a machine frame;
a printing drum;
a back press roller rotatably mounted in the machine frame for selectively pressing a print sheet to the printing drum;
first frame means for supporting the printing drum to be rotatable around a central axis thereof; and
second frame means for supporting the first frame means to be movable along the central axis of the printing drum for at least a distance corresponding to a maximum value of an adjustment of a transverse position of a printed image;
the machine frame having means adapted to removably engage a part of the second frame means for supporting and guiding the second frame means, so as to drawably receive the second frame means, the first frame means supported by the second frame means and the printing drum supported by the first frame means; and
actuation means for adjusting a transverse position of a printed image, the printed image transverse position adjustment actuation means being adapted to selectively move the first frame means relative to the machine frame when the second frame means are mounted in the machine frame.
According to the above-mentioned construction of the drum type printer, an adjustment of a transverse position of a printed image is available by the first frame means rotatably supporting the printing drum is made movable relative to the second frame means along the central axis of the printing drum within a distance corresponding to the maximum value of the printed image transverse position adjustment, so that the construction for movably supporting the first frame means relative to the second frame means can be made optionally fine and high precision as required, regardless of the easiness and toughness for the handling of the second frame means in the mounting and dismounting thereof relative to the machine frame.
In more detail, the printed image transverse position adjustment actuation means may be adapted to act between the first frame means and the machine frame.
In such a construction that the printed image transverse position adjustment actuation means act between the first frame means and the machine frame, the printed image transverse position adjustment actuation means may comprise a shaft portion provided in the first frame means to extend in a direction of extension of the central axis of the printing drum, a shift block supported and guided by the machine frame to be movable along the direction of extension of the central axis of the printing drum and having a bore for selectively receiving the shaft portion of the first frame means, drive source means for selectively driving the shift block along the movable direction thereof, and means for selectively holding the shaft portion of the first frame means in the bore of the shift block when the shaft portion was inserted in the bore.
Or, alternatively, the printed image transverse position adjustment actuation means may be adapted to act between the first frame means and the second frame means.
In both of the construction that the printed image transverse position adjustment actuation means act between the first frame means and the machine frame and the construction that the printed image transverse position adjustment actuation means act between the first frame means and the second frame means, the printed image transverse position adjustment actuation means may comprise a screw portion provided in the first frame means to extend in the direction of extension of the central axis of the printing drum, a nut member having a tapped bore and mounted on the second frame means to be rotatable around a central axis of the tapped bore, and drive source means for selectively rotating the nut member.
In such a construction, the nut member may be stationarily positioned relative to the second frame means with respect to an axial position thereof, or the nut member may be stationarily positioned relative to the machine frame with respect to an axial position thereof when the second frame means have been mounted in the machine frame.
In both of such constructions, the printing drum may have a bearing bore aligned with the central axis thereof at a first end thereof and an annular track along an inner periphery of a second end thereof opposite to the first end thereof,
the first frame means having a first shaft portion at a first end thereof, the first shaft portion extending along the central axis of the printing drum while engaging the bearing bore of the printing drum therethrough so as to rotatably support the first end of the printing drum, second and third shaft portions at a second end thereof opposite to the first end thereof, the second and third shaft portions extending in parallel with th
Kato Hiroyasu
Motoe Katsuro
Oliff & Berridg,e PLC
Riso Kagaku Corporation
Yan Ren
LandOfFree
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