Electrophotography – Internal machine environment – Forced air circulation
Reexamination Certificate
2001-05-16
2003-05-20
Tran, Hoan (Department: 2852)
Electrophotography
Internal machine environment
Forced air circulation
C347S155000, C399S401000
Reexamination Certificate
active
06567629
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to imaging apparatus and methods and more particularly, to apparatus and methods for cooling a sheet of media in an imaging apparatus.
BACKGROUND OF THE INVENTION
Various types of prior art imaging apparatus have been in use. By “imaging apparatus” we mean an apparatus that is configured to produce a given image on a sheet of media. Imaging apparatus include such devices known as printers, copiers, fax machines, and plotters. By “image” we mean to include any image, such as photographs, drawings, symbols, text, or any combination thereof, which is formed by depositing at least one shade or color of pigment onto a sheet of media. By “media” we mean any material onto which pigment can be affixed so as to form an image, including paper and plastic transparencies. That is, an image can range from simple black text on a white sheet of paper media to a complex color photograph on a transparency.
It is understood, then, that many different specific configurations of imaging apparatus exist. One such configuration of an imaging apparatus is that which is generally known as a laser printer. Referring now to
FIG. 1
, a schematic side elevation diagram is shown which depicts some of the basic components of a prior art laser printer apparatus
10
. The prior art laser printer apparatus
10
comprises an infeed tray
22
and an outfeed tray
24
. The infeed and outfeed trays
22
,
24
are each configured to support at least one sheet of media “M.”
The prior art laser printer apparatus
10
also comprises a set of infeed rollers
14
which are configured to feed a given sheet of media “M” along a media path “P” in the feed direction “D.” As is seen, the prior art apparatus comprises an image-producing portion
12
which, in turn, generally comprises at least one laser device and one photoconductor surface (not shown). The image-producing portion
12
is configured to apply toner (not shown), which is in a substantially powdered form, to a sheet of media “M” in order to form an image thereon, while the sheet of media passes by the image-producing portion along the media path “P.” Laser printers are known in the art and, therefore the process of forming an image on a sheet of media by employing a laser device and photoconductor will not be discussed in further detail herein.
As is further evident from a study of
FIG. 1
, the prior art apparatus
10
comprises a fusing portion
16
. The fusing portion
16
is configured to heat the media “M,” along with the toner supported thereon, to a given temperature in order to set, or “fuse,” the toner to the media. That is, generally the powdered toner, which is supported on a sheet of media “M,” is heated by the fusing portion
16
so that the toner is “melted” from its initial powdered form to a substantially “plastic” consistency. This fusing process in which the toner is substantially melted causes the toner to be substantially bonded to the media so as to form the final product of an image bonded to a sheet of media. During this fusing process, the temperature of the media “M” can reach significant levels and can be at least as high as 190°, Centigrade.
As is also seen, a set of outfeed rollers
18
is included in the prior art apparatus
10
. The outfeed rollers
18
move the media “M,” after it has passed the fuser
16
, into the outfeed tray
24
. The media “M” which is supported in the outfeed tray
24
is generally accessible to users of the apparatus
10
so that the sheets of media “M,” which now support finished images, can be retrieved by the users of the apparatus
10
. The location of the fusing portion
16
is generally fixed relative to the set of outfeed rollers
18
. That is, a given fixed distance “L” is defined along the media path “P” between the fusing portion
16
and the set of outfeed rollers
18
.
It is evident, then, that a given period of time which elapses between the moment at which a given sheet of media “M” passes through the fusing portion
16
and the moment at which the given sheet of media “M” passes through the set of outfeed rollers
18
is inversely proportional to the feed rate of the media along the feed path “P.”In other words, faster feed rates, or production rates, will result in shorter elapsed times from the moment the media “M” passes through the fusing portion
16
and the moment at which the media is available for retrieval by the users of the apparatus
10
.
Moving now to
FIG. 2
, a flow chart
30
is shown which depicts a set of prior art steps which can be used to describe the typical operational processes performed on a given sheet of media by the prior art laser printer apparatus
10
during the production of a finished image. The various steps of which the flow chart
30
is comprised will now be discussed with reference to both
FIGS. 1 and 2
. As is evident, the step S
32
serves as the beginning of the flow chart
30
. Moving on from step S
32
, the first operational step is that of S
34
. In accordance with step S
34
, a sheet of media “M” is taken from the infeed tray
22
and fed into the infeed rollers
14
so as to commence the movement of the media along the media path “P” and in the feed direction “D.”
Moving to the next step, that of S
36
, the sheet of media “M” is fed past the image-producing portion
12
, and an image comprising toner is deposited on the media by the image-producing portion. In accordance with the following step S
38
, the sheet of media “M” is fed past the fusing portion
16
, and the toner and media is heated by the fusing portion to a relatively high temperature in order to fuse the image to the media. The next step of S
40
includes passing the sheet of media “M” through the outfeed rollers
18
, and depositing the media in the outfeed tray
24
. The step S
42
denotes the end of the flow chart
30
. As discussed above, the production rate of the prior art apparatus
10
is limited by the need to provide ample time for the media “M” to cool after passing through the fusing portion
16
and before passing through the outfeed rollers
18
and into the outfeed tray
24
.
Briefly referring again to
FIG. 1
, it is evident that at relatively high feed rates, the media “M” has correspondingly less time to cool before exiting the apparatus
10
through the set of outfeed rollers
18
. This can result in the exposure of users of the apparatus
10
to media “M” which is at dangerously high temperatures, which can cause severe burns. In addition, stacked sheets of media “M” which accumulate in the outfeed tray can contain high levels of heat energy which can cause damage to the media and to the apparatus
10
, and can also pose a potential fire hazard.
Furthermore, when a media such as plastic transparencies are used in the apparatus
10
, the cumulative heat energy which is present in a stack of such transparencies can cause one sheet of media to fuse to another sheet. Therefore, feed rates of prior art imaging apparatus, such as the prior art laser printer apparatus
10
, are often limited by the need to allow the media “M” to cool sufficiently before being made available in the outfeed tray
24
.
What is needed then, are imaging apparatus and methods which achieve the benefits to be derived from similar prior art devices, but which avoid the shortcomings and detriments individually associated therewith.
SUMMARY OF THE INVENTION
The invention includes apparatus and methods for cooling a sheet of media on which an image is deposited in an imaging process. Typically, such imaging processes involve heating the media to a relatively high temperature for fusing the image to the media. The instant invention includes various embodiments thereof which are configured to actively reduce the temperature of the media before the media exits the imaging apparatus.
In accordance with a first embodiment of the present invention, an imaging apparatus comprises a cooling surface which is configured to contact a sheet of media and to thereby absorb heat energy there from. The cooling surface can be configured to act as a heat sink to abso
Anderson Bradley J.
Fortier Courtney A.
Herrmann William I.
Johnson Bruce L.
Hewlett--Packard Development Company, L.P.
Tran Hoan
LandOfFree
Cooling device for imaging apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cooling device for imaging apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cooling device for imaging apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3071230