Winding – tensioning – or guiding – Convolute winding of material – With coiled supply
Reexamination Certificate
1999-10-20
2001-10-23
Jillions, John M. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With coiled supply
C242S538100, C399S327000
Reexamination Certificate
active
06305636
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates a to web driving device for cleaning an object or for applying liquid such as oil to an object by the action of contact. The web driving device is equipped in a device such as an image forming apparatus (e.g., a copier, a facsimile, or a printer). More specifically, the web driving device is equipped in a fixing device or a photosensitive device in the image forming apparatus.
2. Discussion of the Background
A conventional web driving device, as depicted in
FIG. 1
, is equipped in a fixing device. The fixing device generally includes a fixing roller
1
that has a heater
3
inside such that a surface of the fixing roller
1
is heated and controlled at prescribed temperature. A press roller
2
presses the fixing roller
1
and makes a nip portion between them. When a sheet of paper
5
having unfixed toner image thereon is fed through the nip portion, the toner image is fixed to the paper
5
. The fixing device further includes a web device having a web
44
made of an unwoven wiper that is constructed of aramid fiber mixed with PET (polyethylene terephthalate) fiber. The web
44
contains oil as required. One edge of the web
44
is fixed to a winding axis
42
and another edge of the web is fixed to a supplying axis
43
. Most of the web
44
is wound in the supplying axis
43
in initial condition. A pressing roller
45
is located between the winding axis
42
and supplying axis
43
for pressing the web
44
to the fixing roller
1
. The web
44
is moved step by step and then the web
44
removes a residual quantity on the fixing roller
1
or supplies oil to the fixing roller
1
. A motor
72
drives the winding axis
42
for winding the web
44
at a constant angle in one action via a transferring mechanism
71
such as a gear or a timing pulley. The pressing roller
45
has a layer made of a silicon rubber or a forming rubber on a core metal.
Construction of the web driving device and amount of sending (or unwinding) of the web has numerous variations depending upon the manner in which the image forming apparatus is going to be utilized. The amount of sending is generally limited to a small amount because the web
44
is restricted in length or setting space. More specifically, the amount of sending is generally limited to between 0.5 mm/hour and 2 mm/hour.
In this conventional web driving device, there is a problem that when the web is pulled unexpectedly (for example during a paper jam) and the fixing roller is manually rotated via a handling knob, then the winding axis is rotated in conjunction with the fixing roller. The reason why the problem comes up is the winding axis is usually put only under light load for helping the supplying axis for taking up the web. More specifically, when a paper
5
is jammed, as depicted in FIG.
2
(
a
), and the paper
5
is taken out along a normal feeding direction (indicated by an arrow), the web
44
may not be drawn by a torque of the fixing roller
1
as the winding axis
42
is locked by the motor
72
in an undriving condition. However, when a paper
5
, as depicted in FIG.
2
(
b
), is taken out along a counter direction of the normal feeding direction (indicated by an arrow), the web
44
is drawn by a torque of the fixing roller
1
(as shown using a dotted lines) because the supplying axis
43
is not locked. Accordingly, cleaning ability of the web
44
is reduced. Furthermore, the web
44
may be caught in the nip portion by the slack when the printing action restarts.
To solve the above problem, a device is disclosed in a Laid-Open Japanese Patent Application No. 08-185074. The device has a locking mechanism for preventing the looseness of the web. The device has a supplying axis including a ratchet gear at the edge thereof, a winding axis for taking up the web, a solenoid actuated in response to winding action of the winding axis.
The solenoid has a ratchet hook that is engaged with the ratchet gear only when the winding axis rotates. However, as a controller must control the action of the solenoid and the action of the winding axis accurately, controlling by the controller becomes difficult. Furthermore, the device must have a ratchet hook and a solenoid of increased rigidity in order to insure that the rotation of the supplying axis is properly stopped. Therefore the device must be upsized.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide a novel web driving device that overcomes the above-mentioned limitations of existing methods and systems.
Another object of the present invention is to provide a novel web driving device that actuates with reliability.
The present invention provides a web driving device including a web, a winding axis connected to a first end of the web and configured to rotate and wind the web about the winding axis in a winding direction, and a supplying axis connected to a second end of the web and configured to rotate. The web driving device further includes a driving device configured to drive the winding axis in the winding direction. The driving device is configured to prevent rotation of the winding axis when the driving device is in an inactive condition. The invention further advantageously provides an intermediate gear device engaged to the winding axis and configured to restrict rotation of the supplying axis when the winding axis stops rotating.
The present invention advantageously includes a first embodiment where the supplying axis includes a first protrusion fixed thereto, and the intermediate gear device includes a second protrusion fixed thereto. In this embodiment the second protrusion is configured to engage the first protrusion to prevent the supplying axis from rotating in at least one direction when the driving device is in the inactive condition. The first protrusion and the second protrusion are preferably configured to allow relative rotation between the supplying axis and the intermediate gear device in a first direction but prevent relative rotation between the supplying axis and the intermediate gear device in a direction opposite to the first direction. The first protrusion is incorporated in a cam surface attached to the supplying axis and the supplying axis is biased towards the intermediate gear device to maintain contact between the second protrusion and the cam surface during rotation of the supplying axis and the intermediate gear device.
The present invention advantageously includes a second embodiment where the supplying axis includes a one-way gear assembly having a one-way clutch configured to engage the supplying axis with the intermediate gear device and prevent the supplying axis from rotating in at least one direction when the driving device is in the inactive condition.
The present invention further advantageously includes a third embodiment where the intermediate gear device includes a first portion engaged to the supplying axis and having a first tooth and a second portion engaged to the winding axis and having a second tooth. The second tooth is configured to engage the first tooth to prevent the supplying axis from rotating in at least one direction when the driving device is in the inactive condition. The first tooth and the second tooth are preferably configured to allow relative rotation between the first portion and the second portion in a first direction but prevent relative rotation between the first portion and the second portion in a direction opposite to the first direction.
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pate
Satoh Masahiko
Seki Takayuki
Jillions John M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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