Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
2002-10-29
2004-12-07
Tran, Hoan (Department: 2852)
Electrophotography
Image formation
Photoconductive member
C074S640000, C074S66500G
Reexamination Certificate
active
06829457
ABSTRACT:
The present disclosure relates to the subject matter contained in Japanese Patent Application No.2001-381884 filed on Dec. 14, 2001 and Japanese Patent Application No.2002-248548 filed on Aug. 28, 2002, which are incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a driving apparatus used with an image formation apparatus, such as a copier or a printer, and in particular to improvements in a driving apparatus for transmitting a driving force from a drive source to a driven body via a multiple-stage gear train and an image formation apparatus using the driving apparatus.
2. Description of the Related Art
Generally, as a technique of driving a driven body such as a photoconductor drum or an intermediate transfer body in an image formation apparatus such as a copier or a printer, a driving apparatus for transmitting a driving force from a drive source such as a motor to a driven body with a multiple-stage gear train (a gear train comprising a plurality of gears meshing with each other successively) is used (for example, refer to JP-A-61-156158).
At this time, the vibration component caused by the gears meshing with each other, a one-revolution component caused by eccentricity of a rotor of the motor, and the like enter the frequencies in the functional area of a human being and thus it is necessary to attenuate the components, etc., for providing stable rotation.
Hitherto, as a remedy, it has been generally known to attach a flywheel onto a driven body shaft of a photoconductor drum, etc., for increasing the inertia amount.
An art of attaching a flywheel of a small inertia body to a separate shaft from a driven body shaft of a photoconductor drum, etc., and increasing the speed of the flywheel, thereby giving a large inertia effect to the driven body is also known (for example, refer to Japanese Patent No. 3013779).
However, in this kind of flywheel technique, the number of parts is increased and the apparatus itself is upsized because of use of at least the flywheel as an inertia body. Thus, for example, to apply a driving apparatus of a multiple-stage gear train to a tandem image formation apparatus, etc., it is extremely difficult to apply the flywheel technique from the viewpoints of miniaturizing and making cheaper the image formation apparatus.
Hitherto, as a technique of decreasing speed fluctuation caused by a gear eccentricity component, a related art is proposed wherein the gears of a gear train are formed as gears of the same shape, for example, the same molded articles or integrally simultaneously worked molded articles and at the assembling time of the correspondence positions of the gears, the gears are selectively placed at the phase positions responsive to the speed fluctuation phases of gear shafts (for example, refer to JP-A-61-156158).
From V=r &ohgr; (where V: Speed, r: Gear radius, and &ohgr;: Angular speed), gears are rotated so that the radiuses of the gears are made the same at the mesh points of the driving apparatus and driven gears, whereby the angular speeds of the driving apparatus and driven gears are made the same for decreasing the eccentricity component of each gear.
However, this type may cope with speed fluctuation caused by the eccentricity component of each gear, but still cannot cope with speed fluctuation caused by the mesh component of each gear.
A technique is disclosed wherein, for example, in a four-cycle intermediate transfer type image formation apparatus, (1) a configuration in which the rotation period of a photoconductor drum drive gear is roughly matched with the rotation period from light exposure to primary transfer and (2) a configuration in which the rotation period of an intermediate transfer body drive gear is roughly matched with the rotation period from primary transfer to secondary transfer are adopted, thereby preventing expansion or contraction of an image caused by the difference between the peripheral speed at an image write position onto a photoconductor drum and that at a transfer position and further preventing expansion or contraction of an image caused by the difference between the speed at the transfer time from the photoconductor drum and that at the transfer time to a record material (for example, refer to JP-A-9-43932).
In this technique, it may be possible to roughly cancel fluctuation (color shift) of the one-revolution period of the photoconductor drum and an intermediate transfer body, caused by the eccentricity of the gears for driving the photoconductor drum and the intermediate transfer body, but an image defect (banding) caused by expansion or contraction of an image caused by the speed fluctuation of gear mesh frequency is not remedied at all; this is a technical problem.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a driving apparatus for making it possible to effectively prevent speed fluctuation caused by the mesh components of a multiple-stage gear train without upsizing the driving apparatus itself and an image accumulation apparatus using the driving apparatus.
The inventor et al. analyzed the mesh state of a gear pair of a multiple-stage gear train model and recognized that the mesh state of gear teeth of a G1 and G2 gear pair changed from moment to moment and the number of mesh points h became two or one and that speed fluctuation was caused by the mesh components of the multiple-stage gear train based on such a behavior, as shown in FIGS.
37
(
a
) to
37
(
c
) and FIGS.
38
(
a
) and (
b
).
When the mesh state of the gear teeth at each mesh point of the G1 and G2 gear pair was changed in the multiple-stage gear train model, for example, with a crest crest mesh transmission technique (transmission technique in which when the gear tooth at the input side mesh point of the gear G1 is a crest position, the gear tooth at the output side mesh point of the gear G1, namely, at the mesh point with the gear G2 is a crest position), the results of the speed fluctuations of the gears G1 and G2 and the difference between the speed fluctuations were obtained as shown in FIG.
39
.
On the other hand, with a crest trough mesh transmission technique (transmission technique in which when the gear tooth at the input side mesh point of the gear G1 is a crest position, the gear tooth at the output side mesh point of the gear G1, namely, at the mesh point with the gear G2 is a trough position), the results of the speed fluctuations of the gears G1 and G2 and the difference between the speed fluctuations were obtained as shown in FIG.
40
.
When the speed fluctuation difference between the gears G1 and G2 in the crest crest mesh transmission technique was compared with that in the crest trough mesh transmission technique, the result shown in
FIG. 41
was obtained and a clear difference was observed between the speed fluctuation difference waveforms.
Then, the inventor et al. obtained the knowledge that the gear speed fluctuation might be able to be controlled by changing the mesh state at each mesh point of the multiple-stage gear train, and have thought out the invention.
That is, as shown in
FIG. 1
, according to the invention, there is provided a driving apparatus for transmitting a driving force from a drive source
1
to a driven body (not shown) via a multiple-stage gear train
2
(consisting of, for example, gears
2
a
to
2
c
), characterized in that in the multiple-stage gear train
2
, the speed fluctuation phase of a mesh frequency occurring at each mesh point of the gear train consisting of the gears
2
a
to
2
c
to a target gear
2
c
is set in the range in which the speed fluctuation amplitude of the target gear
2
c
positioned downstream at the third stage or later is equal to or less than the speed fluctuation amplitude of the immediately preceding mesh gear
2
b
positioned upstream.
In such technical means, the multiple-stage gear train
2
refers to the form of a train of a large number of gears meshing with each other. Each of the gears
2
a
to
2
c
making up the multi
Hanzawa Tokuaki
Hokari Norio
Kibayashi Susumu
Mitamura Yoshihiko
Nishikawa Satoru
Fuji 'Xerox Co., Ltd.
Morgan & Lewis & Bockius, LLP
Tran Hoan
LandOfFree
Driving apparatus and image formation apparatus using the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Driving apparatus and image formation apparatus using the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Driving apparatus and image formation apparatus using the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3282385