Electrophotography – Control of electrophotography process – Control of developing
Reexamination Certificate
2000-07-24
2001-07-17
Grainger, Quana M. (Department: 2852)
Electrophotography
Control of electrophotography process
Control of developing
C366S182400, C399S237000
Reexamination Certificate
active
06263171
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink density adjusting mechanism and an electrophotographic apparatus using this ink density adjusting mechanism, and more particularly to an ink density adjusting mechanism for use in an electrophotographic process using liquid ink and an electrophotographic apparatus equipped with this ink density adjusting mechanism.
2. Description of the Related Art
Conventionally, a transmission-type sensor, with a light-emitting device and a light-receiving device as the density detecting means, has been used on an electrophotographic apparatus using liquid ink to keep the ink density at a constant level. This technology is disclosed, for example, in
FIGS. 1-4
of Japanese Patent Laid-Open Publication No. Hei 8-314283.
To quickly start printing at a right density the next time printing is to start, it is an effective way to sense the ink density after printing and then adjust the ink density at a right density. A transmission type density sensor, though simple in circuit configuration, requires ink to be circulated for sensing the correct density. Circulating ink for density adjustment after printing, that is, at non-print time, means that ink must be supplied also to a developing unit and that stains are sometimes generated on a photo-sensitive medium on which images are to be developed.
As described above, the conventional ink density adjusting mechanism circulates ink at non-print time in order to adjust the density. One of the problems with this mechanism is that, because ink is circulated also to the developing unit, stains are sometimes generated on a photo-sensitive medium on which images are to be developed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink density adjusting mechanism, which does not generate stains on a photo-sensitive medium on which images are to be developed even if ink is circulated at non-print time to adjust the density, and an electrophotographic apparatus using this ink density adjusting mechanism.
The electrophotographic apparatus according to the present invention, which uses liquid ink, has an ink density adjusting mechanism comprising a developing unit; an ink tank; a pump which circulates the ink in the ink tank; a valve which switches a circulation path of the ink between the circulation path supplying the ink to the developing unit and the circulation path bypassing the developing unit; and a density sensor which senses a density of the ink.
The ink density adjusting mechanism according to the present invention has a circulation path switching valve between the developing unit and the transmission type density sensor of the electrophotographic apparatus. This valve, when on, cuts off the ink flow path to the developing unit and circulates the ink through the ink tank to allow the ink to circulate without flowing it into the developing unit. Therefore, ink density adjustment, even if performed at non-print time, does not stain the photosensitive materials, thus making it possible to print at proper density any time and to eliminate an uneven density in a print image.
REFERENCES:
patent: 4671309 (1987-06-01), Iemura et al.
patent: 6170977 (2001-01-01), Yuakushji
patent: 8-314283 (1996-11-01), None
Grainger Quana M.
NEC Corporation
Young & Thompson
LandOfFree
Ink density adjusting mechanism and electrophotographic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink density adjusting mechanism and electrophotographic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink density adjusting mechanism and electrophotographic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2493900