Sheet feeding or delivering – Delivering – With transfer means between conveyor and receiver
Reexamination Certificate
2000-02-04
2001-11-27
Yan, Ren (Department: 2854)
Sheet feeding or delivering
Delivering
With transfer means between conveyor and receiver
C271S188000, C400S185000
Reexamination Certificate
active
06322068
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a sheet discharge mechanism provided for an ink jet printer for forming a designated image on a sheet of paper with ink ejected from an ink head.
(2) Description of the Prior Art
In an ink jet printer in which an image is formed on a sheet of paper with ejected ink from an ink head, the sheets with images formed with ink are discharged and stacked one over another on the sheet output tray. Therefore, when images are recorded continuously on a multiple number of sheets, a sheet having an image formed with ink is laid over the previous one before its ink dries so that the sheets may be stained or the image of ink may be disrupted by contact of the undried sheet. To avoid this, continuous image forming may be performed at intervals of a time which allows for drying of the ink on the sheet. However, drying of the ink on the sheet usually needs about 40 to 60 seconds, which makes high-speed image forming impossible.
In order to solve this problem, there has been a known printer inside which a drying device for drying the ink of the image formed on the paper is provided. However, provision of such a drying device therein makes the printer body bulky and degrades its economy.
Japanese Patent Application Laid-Open Hei 6 No.91861 discloses an ink jet printer in which when a sheet of paper having an image formed with ink is discharged from the printer body, the sheet being discharged is forcibly curved so as to be projected downward with respect to the direction perpendicular to the direction of discharge of the paper. In this way, curving the paper being discharged from the printer body can prevent the leading end, with respect to the direction of discharge, of the sheet from bending or drooping downwards so that the sheet can be kept horizontal until the sheet is discharged completely from the printer body. Therefore, the sheet being discharged can be held over the sheet previously discharged for an appropriate period of time and then stacked on the sheet output tray, thus making it possible to lengthen the time for the sheet to drop onto the sheet output tray and hence dry the ink on the previous sheet on the sheet output tray.
However, even with such a configuration in which a sheet is discharged from the printer body by being curved so as to be kept horizontal, there is a fear that the sheet may droop without being kept horizontal if the sheet itself has low rigidity and can be readily flexed so that the sheet may come in contact with the previous sheet on the sheet output tray and stain the sheet being discharged or disrupt the image on the previous sheet. This problem also occurs when a large sized sheet is used.
SUMMARY OF THE INVENTION
The present invention is to solve the above problem and it is therefore an object of the present invention to provide a sheet discharge mechanism for an ink jet printer, which can prevent occurrence of image disruption and sheet staining due to undried ink when sheets of a low rigidity or of a large size are stacked one over another on the sheet output tray.
The present invention has been devised in order to achieve the above object and the present invention is configured as follows:
In accordance with the first aspect of the present invention, a sheet discharge mechanism for an ink jet printer, includes: a first sheet output tray on which sheets with images formed with ink by the ink jet mechanism are sequentially stacked one over another; a second sheet output tray located above the first sheet output tray for holding the sheet with an image formed with ink by the ink jet mechanism; and a sheet dropping means for sequentially dropping the sheet held by the second sheet output tray onto the first sheet output tray.
In accordance with the second aspect of the present invention, the sheet discharge mechanism for an ink jet printer having the above first feature is characterized in that the second sheet output tray is configured so as to curve the sheet being held thereby in such a manner that the middle part of the sheet with respect to the direction perpendicular to the direction of discharge of the sheet is projected downward.
In accordance with the third aspect of the present invention, the sheet discharge mechanism for an ink jet printer having the above first feature is characterized in that the sheet dropping means includes a sheet discharge arm which is rotated so as to come into contact with the rear end of the sheet being held over the second sheet output tray and push it out from the second sheet output tray.
In accordance with the fourth aspect of the present invention, the sheet discharge mechanism for an ink jet printer having the above third feature is characterized in that the sheet discharge arm is configured so as to pass through a cutout portion defined in the second sheet output tray.
In accordance with the fifth aspect of the present invention, the sheet discharge mechanism for an ink jet printer having the above third feature is characterized in that the sheet discharge arm is rotated and stopped based on the operation of the ink head carriage which is moved reciprocatingly by the ink jet mechanism.
In accordance with the sixth aspect of the present invention, the sheet discharge mechanism for an ink jet printer having the above third feature is characterized in that the sheet discharge arm stores the energy for rotational force while it is being stopped.
REFERENCES:
patent: 4844633 (1989-07-01), Greenberg
patent: 5409209 (1995-04-01), Nakamura et al.
patent: 5890822 (1999-04-01), Saikawa et al.
patent: 5927877 (1999-07-01), Kelly et al.
patent: 6148727 (2000-11-01), Parthasarathy et al.
patent: 691861 (1994-04-01), None
Hayashiyama Shunichi
Horinaka Hajime
Iemura Hirotoshi
Kimura Masaharu
Ochi Norihiro
Birch & Stewart Kolasch & Birch, LLP
Sharp Kabushiki Kaisha
Williams Kevin D.
Yan Ren
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