BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to an image forming apparatus equipped with a dehumidifier
that dehumidifies the inside of the apparatus.
2. Description of the Related Art
[0002] Generally, in a dehumidifier in an image forming apparatus, air in a copying section
containing moisture and dusty toner generated in a developing section are guided into
a dehumidifier by an air distribution fan. Dew is formed by moisture in the air, turned
to droplets, and falls into a recycled water receiver by a cooling fan fitted to a
low-temperature section of a Peltier element. At this time, the dusty toner is captured
by the droplets, and falls into the recycled water receiver together with the droplets.
The air, from which moisture and dusty toner are removed, is exhausted outside of
the dehumidifier and supplied to the copying unit. At this time, by cooling a high-temperature
section of the Peltier element with the air distribution fan via a radiating fin fitted
to the Peltier element, the cooling efficiency of the low-temperature section of the
Peltier element increases. Accordingly, the dehumidification efficiency is improved,
as disclosed in Japanese Patent Application Laid-Open No. H6-83129, paragraph [0035]
to [0036], Figs. 1 and 2.
[0003] The electrophotographic image forming apparatus is apt to be affected by environmental
changes, and a measure against a characteristic change due to temperature and humidity
becomes a large technical problem. For example, the main characteristics of image
processing such as chargeability and toner properties (fluidity and the like) are
largely affected by the humidity, causing defective charging, defective cleaning,
and the like, thereby becoming a cause of defective image formation. Furthermore,
the rigidity and Young's modulus of rubber parts used for a cleaning blade and for
transporting and separating paper change according to the temperature, thereby causing
defective cleaning, jam, and defective transport such as multi feed and the like.
Furthermore, when a transfer material such as paper absorbs moisture, it becomes soft,
thereby decreasing the transport property, or when paper becomes dry, the resistance
increases, thereby causing defective transfer.
[0004] Therefore, an image forming apparatus including a detector that detects the temperature
and humidity in the apparatus, and an adjusting unit that adjusts the temperature
and humidity in the apparatus based on the detection result of the temperature and
humidity detector has been disclosed. For example, Japanese Patent Application Laid-Open
No. H9-81018 discloses an image forming apparatus in which the main part thereof is
configured substantially as a closed space. The humidity in the apparatus is detected
by a humidity detector and compared with a predetermined optimum humidity, and when
there is a difference, a humidity adjusting unit adjusts the humidity in the apparatus.
Japanese Patent Application Laid-Open No. 2003-280467 discloses an image forming apparatus
in which a plurality of imaging units is respectively configured substantially as
a closed space, and a temperature and humidity detector and a temperature and humidity
adjusting unit are provided for each of the imaging units.
[0005] In an assembly process of a conventional dehumidifier, however, since the Peltier
element is susceptible to load and impact, difficulties arise when the Peltier element,
a cooling-and-dehumidifying member, and a heat exhaust member are uncovered, and the
work is complicated.
[0006] In the image forming apparatuses disclosed in Japanese Patent Application Laid-Open
Nos. H9-81018 and 2003-280467, the position between the temperature and humidity detector
and a heat source that generates heat in the apparatus is not taken into consideration.
When the temperature and humidity detector is installed near the heat source, for
example, a fixing apparatus that fixes a toner image by thermo-compression bonding,
the temperature and humidity detector is directly affected by the heat from the heat
source. Therefore, even if the temperature and humidity adjusting unit is operated
based on the detection result of the temperature and humidity detector, it is difficult
to control the ambient atmosphere in the apparatus and the imaging units to a temperature
or humidity suitable for image formation.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to at least solve the problems in the conventional
technology.
[0008] According to an aspect of the present invention, an image forming apparatus includes
a flow path forming member that forms a dehumidified air flow path and an exhaust
heat air flow path, a dehumidifier including a cooling-and-dehumidifying member positioned
in the dehumidified air flow path, and a heat exhaust member positioned in the exhaust
heat air flow path, a case that covers an aperture common to the dehumidified air
flow path and the exhaust heat air flow path, and an imaging unit connected to the
dehumidifier by a connecting air flow path through which dehumidified air is introduced
into the imaging unit from the dehumidified air flow path.
[0009] According to another aspect of the present invention, an image forming apparatus
includes a flow path forming member that forms a dehumidified air flow path and an
exhaust heat air flow path, a dehumidifier including a cooling-and-dehumidifying member
positioned in the dehumidified air flow path, a heat exhaust member positioned in
the exhaust heat air flow path, and a Peltier element positioned between the cooling-and-dehumidifying
member and the heat exhaust member, a case that covers an aperture common to the dehumidified
air flow path and the exhaust heat air flow path, and an imaging unit connected to
the dehumidifier by a connecting air flow path through which dehumidified air is introduced
into the imaging unit from the dehumidified air flow path.
[0010] According to still another aspect of the present invention, an air intake and exhaust
system includes a flow path forming member that forms a dehumidified air flow path
and an exhaust heat air flow path, a dehumidifier including a cooling-and-dehumidifying
member positioned in the dehumidified air flow path, and a heat exhaust member positioned
in the exhaust heat air flow path, an inlet port to which the dehumidifier is connected,
a case that covers an aperture common to the dehumidified air flow path and the exhaust
heat air flow path, a connecting air flow path through which dehumidified air is introduced
into an imaging unit from the dehumidified air flow path, a dehumidifying fan that
sends an air flow from the dehumidified air flow path to the connecting air flow path,
and a heat exhaust fan that discharges exhaust heat from the exhaust heat air flow
path to outside.
[0011] According to still another aspect of the present invention, an air intake and exhaust
system includes a flow path forming member that forms a dehumidified air flow path
and an exhaust heat air flow path, a dehumidifier including a cooling-and-dehumidifying
member positioned in the dehumidified air flow path, a heat exhaust member positioned
in the exhaust heat air flow path, and a Peltier element positioned between the cooling-and-dehumidifying
member and the heat exhaust member, an inlet port to which the dehumidifier is connected,
a case that covers an aperture common to the dehumidified air flow path and the exhaust
heat air flow path, a connecting air flow path through which dehumidified air is introduced
into an imaging unit from the dehumidified air flow path, a dehumidifying fan that
sends an air flow from the dehumidified air flow path to the connecting air flow path,
and a heat exhaust fan that discharges exhaust heat from the exhaust heat air flow
path to outside.
[0012] According to still another aspect of the present invention, an image forming apparatus
includes a plurality of imaging units that forms a toner image on an image carrier,
a temperature/humidity detector that detects temperature and humidity in the image
forming apparatus, a temperature/humidity adjusting unit that adjusts temperature
and humidity in the image forming apparatus, a controller that controls the temperature/humidity
adjusting unit based on a detection result of the temperature/humidity detector to
adjust temperature and humidity to a predetermined range, and a heat source that generates
highest temperature in the image forming apparatus, wherein the temperature/humidity
detector is located near one of the imaging units located furthest from the heat source.
[0013] According to still another aspect of the present invention, an image forming apparatus
includes a plurality of imaging units that forms a toner image on an image carrier,
a temperature/humidity detector that detects temperature and humidity in each of the
imaging units, a temperature/humidity adjusting unit that adjusts temperature and
humidity in each of the imaging units, a controller that controls the temperature/humidity
adjusting unit based on a detection result of the temperature/humidity detector to
adjust temperature and humidity to a predetermined range, and a heat source that generates
highest temperature in the image forming apparatus, wherein the temperature/humidity
detector is located in one of the imaging units located furthest from the heat source.
[0014] The above and other objects, features, advantages and technical and industrial significance
of this invention will be better understood by reading the following detailed description
of presently preferred embodiments of the invention, when considered in connection
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0015]
Fig. 1 is a block diagram of an image forming apparatus according to a first embodiment
of the present invention;
Fig. 2 is a perspective view of a dehumidifier used in the first embodiment;
Fig. 3 is a perspective view of the dehumidifier used in the first embodiment;
Fig. 4 is a plan view of the dehumidifier used in the first embodiment;
Fig. 5 is a plan view of a dehumidifier used in the second embodiment;
Fig. 6 is a plan view of a dehumidifier used in the third embodiment;
Fig. 7 is a plan view of another example of the dehumidifier used in the third embodiment;
Fig. 8 is a perspective view of an image forming apparatus according to a fourth embodiment
of the present invention, with a part of the configuration being shown in broken-out
section;
Fig. 9 is a flowchart of an operation performed by the dehumidifier of the present
invention;
Fig. 10 is a schematic block diagram of the inner configuration of a printer according
to a fifth embodiment of the present invention;
Fig. 11 is a control block' diagram of the printer;
Fig. 12 is a schematic block diagram of the inner configuration of a printer according
to another embodiment;
Fig. 13 depicts the configuration of a desiccant air conditioner;
Fig. 14 depicts the configuration of an air conditioner using a Peltier element; and
Fig. 15 is a characteristic diagram of the relation between temperature and saturated
water vapor content.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Exemplary embodiments of the present invention will be described below with reference
to accompanying drawings. The present invention is not limited to these embodiments.
[0017] Figs. 1 to 4 depict a first embodiment of the present invention. In Figs. 1 to 4,
like or equivalent elements are designated with like or similar reference numerals,
and redundant explanations thereof are omitted.
[0018] Fig. 1 is a block diagram of the principle of an image forming apparatus according
to the first embodiment of the present invention. An image forming apparatus 1 includes
a dehumidifier 13 having a Peltier element 10 arranged between a cooling-and-dehumidifying
member 11 and an heat exhaust member 12, a dehumidifier/exhaust heat case 15 that
integrally covers a common aperture of a dehumidified air flow path A provided on
a side of the cooling-and-dehumidifying member 11 and an exhaust heat air flow path
B provided on a side of the heat exhaust member 12, and an electrophotographic imaging
unit 14 connected to a subsequent stage of the dehumidifier 13 for introducing dehumidified
air C from the dehumidified air flow path A through an air flow path 24.
[0019] The image forming apparatus 1 includes an inlet port 16, the dehumidifier 13 connected
to the inlet port 16, the air flow path 24 located on a downstream side of the dehumidifier
13, the imaging unit 14 connected to the air flow path 24, an exhaust path 23 located
on a downstream side of the imaging unit 14, and an exhaust port 17 located at the
end of the exhaust path 23.
[0020] The dehumidifier 13 includes a dehumidifying fan 21, the cooling-and-dehumidifying
member 11 in a form of a fin located on a discharge side of the dehumidifying fan
21 for increasing the contact area with the air, the heat exhaust member 12 in a form
of a fin located on a downstream side of the inlet port 16 for increasing the contact
area with the air, and a heat exhaust fan 20 located on a downstream side of the heat
exhaust member 12.
[0021] The imaging unit 14 is located between the air flow path 24 and the exhaust path
23, and includes a humidity detector 8 that detects the humidity inside the apparatus,
a transfer paper container 26 for receiving transfer paper 28, a transfer paper transport
unit 29, a drum-like photoconductor 31, and an image transfer unit 32 that transfers
an image onto the photoconductor 31. The humidity detector 8 detects the relative
humidity in the imaging unit 14, and when the detected humidity indicates a predetermined
value or higher, dehumidifies the air in the dehumidifier/exhaust heat case 15 by
operating predetermined equipment arranged in the dehumidifier/exhaust heat case 15,
to supply dehumidified air from the dehumidifier/exhaust heat case 15 to the imaging
unit 14. The function and the like of the humidity detector 8 are explained later
in detail.
[0022] In the image forming apparatus 1, an exhaust-heat foreign-matter removing member
19 can be provided on an inlet port side of the heat exhaust fan 20 provided in the
dehumidifier 13, as a dustproof measure. A dehumidification foreign-matter removing
member 18 can be provided inside of the air flow path 24, as well. In the first embodiment,
to enable stable operation of the imaging unit 14 and prevent an abnormal image, a
unit that attracts fine particles in the air by a fine particles-removing filter or
a static elimination filter can be appropriately used.
[0023] An air intake and exhaust system includes the inlet port 16 for drawing the air in,
the dehumidifier 13 having the Peltier element 10 arranged between the cooling-and-dehumidifying
member 11 and the heat exhaust member 12, the dehumidifier/exhaust heat case 15 that
integrally covers the common aperture of the dehumidified air flow path A provided
on a side of the cooling-and-dehumidifying member 11 and the exhaust heat air flow
path B provided on the side of the heat exhaust member 12, the air flow path 24 for
allowing the dehumidified air C to pass from the dehumidified air flow path A to the
imaging unit 14, and the heat exhaust fan 20 for exhausting exhaust heat D from the
exhaust heat air flow path B. In Fig. 1, reference letter E represents exhaust air
from the imaging unit 14.
[0024] Fig. 2 is a perspective view of the dehumidifier 13 used in the image forming apparatus
according to the first embodiment. Overlapping explanations for like members as in
Fig. 1 are omitted.
[0025] The dehumidifier 13 includes the dehumidifier/exhaust heat case 15 that is located
in an area enclosed by a two-dot chain line, and integrally covers the common aperture
of the dehumidified air flow path A and the exhaust heat air flow path B enclosed
by a housing 22. An insulating member 9 that increases the dehumidification effect
can be provided at a corner on the back of the dehumidifier/exhaust heat case 15.
[0026] The dehumidifier 13 is provided with an exhaust port 17a on the left side of the
front face, and can exhaust the exhaust air exhausted by the heat exhaust fan 20.
A water absorption/diffusion member 25 is provided respectively on a bottom face and
a vertical surface between the exhaust port 17a and the heat exhaust fan 20, so that
droplets generated by dewing from the moisture in the air cooled by the cooling-and-dehumidifying
member 11 (see Fig. 1) can be allowed to infiltrate in the water absorption/diffusion
member 25.
[0027] The dehumidifier 13 is provided with the inlet port 16 on the right of the front
face, and can introduce the air through a dehumidification foreign-matter removing
member 18a covering the inlet port 16 to execute dust-proof measures.
[0028] Fig. 3 is a perspective view of the dehumidifier 13 used in the image forming apparatus
according to the first embodiment. The dehumidifier/exhaust heat case 15 (see Fig.
1) is removed from the housing 22. Overlapping explanations for like members as in
Fig. 2 are omitted.
[0029] The dehumidifier 13 includes an inlet port 16b located on the front face of the dehumidifying
fan 21, the inlet port 16b separated from the dehumidifying fan 21, the water absorption/diffusion
member 25 located near the inlet port 16a, the exhaust-heat foreign-matter removing
member 19 provided at an inlet port of the heat exhaust fan 20, and a plurality of
the cooling-and-dehumidifying members 11 located on the downstream of the dehumidifying
fan 21.
[0030] The cooling-and-dehumidifying members 11 has an opening formed substantially'at the
center of a wall, which separates air flow drawn in by a negative pressure by the
heat exhaust fan 20, and air flow pressurized by the dehumidifying fan 21, and can
improve the dehumidification effect and the heat exhaust effect.
[0031] The operation of the image forming apparatus 1 is explained with reference to Fig.
1 and Fig. 4. In the image forming apparatus 1, the air drawn in from the dehumidified
air flow path A is dehumidified by the cooling-and-dehumidifying member 11, and the
dehumidified air is fed to the imaging unit 14 through the inner air flow path 24.
[0032] The dehumidifier 13 feeds the dehumidified air to the imaging unit 14, to reduce
changes in the characteristic values (hardness, Young's modulus, and the like) of
rubber parts, changes in electric charges of a developer, and changes in toner properties
(fluidity and the like), and hence, can provide a system having a stable imaging function.
Furthermore, occurrence of abnormal images such as image blur occurring under a high
humidity condition can be suppressed.
[0033] In this example, the humidity detector 8 is fitted to an imaging unit (developing
unit) 33d (see Fig. 8) in the imaging unit 14 (see Fig. 1). The humidity detector
8 is for detecting the humidity in the imaging unit, and can be also used at the time
of process control. Alternatively, a temperature/humidity detector can be used.
[0034] The dehumidifier 13 operates, as shown in a flowchart shown in Fig. 9, when the humidity
detector 8 indicates relative humidity of 60% or higher. More specifically, when the
humidity detector 8 indicates relative humidity of 60% or higher, the dehumidifying
fan 21 (heat-absorbing fan), the Peltier element 10, and the heat exhaust fan 20 (radiating
fan) are energized, and the outside air is introduced, respectively, to the dehumidified
air flow path A by the dehumidifying fan 21 (heat-absorbing fan), and to the exhaust
heat air flow path B by the heat exhaust fan 20 (radiating fan). The outside air introduced
to the dehumidified air flow path A is dehumidified by the cooling-and-dehumidifying
member 11, cooled by the Peltier element 10 to turn into the dehumidified air C, and
fed to the imaging unit 14 through the air flow path 24. The outside air introduced
to the exhaust heat air flow path B is heated by the heat from the heat exhaust member
12, heated by the Peltier element 10, absorbs water vapor evapotranspirated by the
water absorption/diffusion member 25 to turn into exhaust heat D, and is exhausted
from the exhaust port 17,
[0035] When the humidity in the imaging unit 14 reaches a certain value, the dehumidifier
13 is operated as shown in Fig. 9. Accordingly, the humidity in the imaging unit 14
can be maintained at a certain value or less, thereby realizing a stable image quality.
Furthermore, by operating the dehumidifier 13 only when the humidity detector 8 indicates
a certain humidity, energy saving can be realized. In addition, various sensors in
the imaging unit 14 can be cleaned by the wind pressure of the air fed to the imaging
unit 14, to improve the detection accuracy.
[0036] To operate the dehumidifier 13, much power is required. On the other hand, in the
state that paper is fed to the image forming apparatus 1, the influence of the humidity
with respect to the imaging unit 14 is small. Therefore, by operating the dehumidifier
13 only in the state that paper is not fed to the imaging unit 14, power consumed
by the whole image forming apparatus 1 can be suppressed. Furthermore, when a user
wishes to save energy, the dehumidifier 13 can be left inactivated completely.
[0037] The dehumidifier 13 has the Peltier element 10, the cooling-and-dehumidifying member
11, and the heat exhaust member 12, and can be covered and integrally formed with
the housing 22 and the dehumidifier/exhaust heat case 15 that form the dehumidified
air flow path A and the exhaust heat air flow path B. An insulating member 9a shown
in Fig. 4 insulates the dehumidified air flow from the inner temperature of the image
forming apparatus 1, to increase the dehumidification effect.
[0038] By using the Peltier element 10 in the dehumidifier 13, the apparatus can be downsized
and energy saving can be realized. For example, the apparatus is made small and simplified
by using the Peltier element 10 shown in Fig. 4.
[0039] In the dehumidifier 13, the cooling-and-dehumidifying member 11 is a cooling fin,
and a heat-conduction member (not shown) is clamped between the heat absorbing surface
of the Peltier element 10 and the dehumidifier 13. Likewise, the heat exhaust member
12 here is a radiating fin, and a heat-conduction member (not shown) is clamped between
the heat generating surface of the Peltier element 10 and the dehumidifier 13.
[0040] An insulating member 9b is provided at an opening of a wall, which separates the
dehumidified air flow path A from the exhaust heat air flow path B, and serves as
an insulating member that insulates between the cooling-and-dehumidifying member 11
(cooling fin) and the heat exhaust member 12 (radiating fin).
[0041] The housing 22 forms a part of the dehumidified air flow path A and the exhaust heat
air flow path B surrounding the dehumidifier 13, and the common aperture of the dehumidified
air flow path A and the exhaust heat air flow path B is exposed. The common aperture
is integrally covered with the dehumidifier/exhaust heat case 15, thereby providing
the dehumidified air flow path A and the exhaust heat air flow path B, to separate
the air flow. The water absorption/diffusion member 25 absorbs and transports dehumidified
water generated in the cooling-and-dehumidifying member 11.
[0042] The dehumidifying fan 21 serves as a fan for feeding air to the cooling-and-dehumidifying
member 11, and sends dehumidified air from the dehumidified air flow path to the air
flow path 24. On the other hand, the heat exhaust fan 20 absorbs air from the heat
exhaust member 12 and exhausts heated air.
[0043] As shown in Fig. 4, the water absorption/diffusion member 25 can absorb dehumidified
water dropped from the cooling-and-dehumidifying member 11, and transport water horizontally.
That is, since the water absorption/diffusion member 25 horizontally transports water
formed by dewing in the cooling-and-dehumidifying member 11 at any time, it is not
necessary to provide a reservoir for collecting a large amount of water below the
cooling-and-dehumidifying member 11, and hence, water leak due to an influence of
the image forming apparatus 1 being vibrated or inclined can be prevented.
[0044] Furthermore, a reservoir area for collecting dehumidified water can be provided side
by side in the dehumidifier 13, so as to collect water formed by dewing temporarily.
That is, by providing a reservoir area in the dehumidifier 13, dehumidified water
generated in the cooling-and-dehumidifying member 11 can be collected as it is in
the dehumidifier 13.
[0045] Since the water absorption/diffusion member 25 is installed on the bottom face and
the vertical surface along the exhaust heat air flow path B, the absorbed water can
be easily evaporated even in a space-saving area. Particularly, since the air flow
after having passed the heat exhaust member 12 is warm air as compared to the air
flow at the inlet port, the evaporation ability of water absorbed by the water absorption/diffusion
member 25 can be improved.
[0046] Thus, since the dehumidifier 13 has an evaporative mechanism of the dehumidified
water, the maintenance property of the dehumidifier and the downsizing effect can
be improved. By evaporating the dehumidified water in the exhaust heat air flow path,
a water storage tank having a large capacity, a disposal operation of water, and the
like are not required.
[0047] In the image forming apparatus 1, the area of the imaging unit 14 to be dehumidified
is set to be the vicinity of the photoconductor 31 and other process units adjacent
thereto (for example, the transfer paper container 26, the transfer paper transport
unit 29, and the image transfer unit 32), thereby promoting downsizing and energy
saving.
[0048] Furthermore, by providing the imaging unit 14 in a substantially closed process cartridge
including the photoconductor 31 and at least one other process unit (for example,
the image transfer unit 32), the dehumidification efficiency can be increased, thereby
enhancing downsizing and energy saving of the image forming apparatus 1.
[0049] Furthermore, if the area to be dehumidified is extended up to the vicinity of the
area including the transfer paper 28 and the transfer paper transport unit 29 and
to the inside of the transfer paper container 26, the transfer paper 28 and the transfer
paper transport unit 29 are prevented from absorbing moisture excessively as compared
to the atmosphere, thereby providing stable transportability and transferability.
Furthermore, since the exhaust-heat foreign-matter removing member 19 is provided
in the exhaust heat air flow path B or the dehumidification foreign-matter removing
member 18 is provided in the dehumidified air flow path A, even if there is foreign
matter such as dust in the outside air, the parts in the air-conditioned area in the
image forming apparatus 1 can be effectively prevented from being soiled,
[0050] Thus, in the first embodiment, the imaging system can be stabilized by temperature
control performed by dehumidifying the air in the dehumidified air flow path, and
occurrence of abnormal images in a high-temperature environment can be also prevented
by dehumidifying the air in the image forming apparatus 1. By adopting the configuration
of a monolithic dehumidifier 13 covered with the dehumidifier/exhaust heat case 15,
an image forming apparatus in which the dehumidified air and the exhaust air are not
mixed together can be provided.
[0051] Since the image forming apparatus 1 includes the monolithic dehumidifier 13 covered
with the dehumidifier/exhaust heat case 15, unbalanced load and impact with respect
to the Peltier element 10 can be effectively prevented in a process of assembling
the dehumidifier 13 in the image forming apparatus 1.
[0052] Furthermore, by adopting the monolithic dehumidifier 13 including the heat exhaust
fan 20 covered with the dehumidifier/exhaust heat case 15, gaps and joints in the
exhaust path between the heat exhaust member 12 and the heat exhaust fan 20 can be
reduced. Accordingly, the heat in the dehumidifier 13 can be exhausted efficiently,
and the dehumidification efficiency can be also improved.
[0053] Since the dehumidifying fan 21 is integrally formed with the dehumidifier 13, gaps
and joints in the exhaust path between the heat exhaust member 12 and the heat exhaust
fan 20 is reduced, and hence, the air can be efficiently dehumidified.
[0054] Since the dehumidifying fan 21 pressurizes the outside air and sends the air to be
dehumidified to the dehumidifier 13, it is not necessary to provide an imaging unit
air flow fan, thereby enabling reduction in the number of parts of the image forming
apparatus 1.
[0055] Even if there is foreign matter such as dust in the outside air, the dehumidification
foreign-matter removing member 18 or the exhaust-heat foreign-matter removing member
19 removes the foreign matter. Accordingly, the internal parts in the image forming
apparatus 1 can be prevented from being soiled.
[0056] That is, by providing the foreign matter removing member in each air flow path, even
if there is foreign matter such as dust in the outside air, the parts in the air-conditioned
area can be prevented from being soiled. Furthermore, since the respective foreign
matter removing members are integrally formed with the dehumidifier 13 and there is
little gap in the respective air flow paths, the inner parts in the image forming
apparatus 1 can be effectively prevented from being soiled.
[0057] By making the imaging unit 14 substantially closed, natural exchange with the air
outside the image forming apparatus 1 is reduced, thereby improving the dehumidification
effect. Furthermore, since the dehumidification efficiency is improved, energy consumption
can be reduced.
[0058] By performing dehumidification with respect to a limited area, that is, the photoconductor
and the process units adjacent thereto, which have a large dehumidification effect,
the dehumidification efficiency is improved, thereby enabling downsizing and energy
saving.
[0059] Furthermore, by integrally forming the area to be dehumidified as a process cartridge,
the closed condition of the area to be dehumidified can be easily maintained, to increase
the dehumidification efficiency, thereby enabling downsizing and energy saving of
the image forming apparatus 1.
[0060] Furthermore, by expanding the area to be dehumidified up to the vicinity of the area
including the transfer paper 28 and the transfer paper transport unit 29 and to the
inside of the transfer paper container 26, the transfer paper 28 and the transfer
paper transport unit 29 are prevented from absorbing moisture excessively, thereby
improving stable transportability and transferability of the transfer paper 28.
[0061] Fig. 5 is a plan view of a dehumidifier used in the image forming apparatus according
to a second embodiment of the present invention. Overlapping explanations of like
elements in the dehumidifier shown in Fig. 4 are omitted.
[0062] The air pressurized and fed from the dehumidified air flow path shown on the right
side of Fig. 5 is transferred to the air flow path 24 (see Fig. 1) on the downstream
side, through the cooling-and-dehumidifying member 11. Dust mixed in the air introduced
from the outside is filtered by the dehumidification foreign-matter removing member
18 arranged between the cooling-and-dehumidifying member 11 and the air flow path
24, thereby preventing contamination of the photoconductor 31 and the like.
[0063] Figs. 6 and 7 are plan views of the dehumidifier used in an image forming apparatus
according to a third embodiment of the present invention. Overlapping explanations
of like elements in the dehumidifier shown in Fig. 4 are omitted.
[0064] The air pressurized and fed from the dehumidified air flow path shown on the right
side of Fig. 6 is transferred to the air flow path 24 (see Fig. 1) on the downstream
side, through the cooling-and-dehumidifying member 11. Dust mixed in the air introduced
from the outside is filtered by a common foreign matter removing member 27 arranged
between the cooling-and-dehumidifying member 11 and the air flow path 24, thereby
preventing contamination of the photoconductor 31 and the like.
[0065] The common foreign matter removing member 27 is inserted into a through opening provided
in the wall separating the dehumidified air flow path and the exhaust heat air flow
path, and extended to the discharge opening side of the heat exhaust fan 20. In this
case, the common foreign matter removing member 27 can effectively remove the dust
mixed in the exhaust heat air flow passing through the exhaust heat air flow path,
thereby preventing deterioration in the durability or the required performance of
the dust-proof parts in the image forming apparatus 1.
[0066] Fig. 7 is a plan view of a modified example of the third embodiment. The common foreign
matter removing member 27 is provided near the heat exhaust fan 20 in Fig. 6. However,
in the modified example shown in Fig. 7, a common foreign matter removing member 27a
is arranged between the dehumidifying fan 21 and the cooling-and-dehumidifying member
11.
[0067] Since the common foreign matter removing member 27a is located on the upstream of
the exhaust heat air flow path and the dehumidified air flow path, the foreign matter
mixed in the absorbed air can be removed at an early stage. Accordingly, such a problem
that dust adheres on the fins in the cooling-and-dehumidifying member 11 and the heat
exhaust member 12 can be effectively prevented.
[0068] Thus, in the third embodiment, since the dehumidification foreign-matter removing
member and the exhaust-heat foreign-matter removing member are constructed as one
part, the number of parts can be reduced, thereby reducing the number of processes
in the maintenance work.
[0069] Fig. 8 is a perspective view of an image forming apparatus according to a fourth
embodiment of the present invention, with a part of the configuration being cut. Overlapping
explanations of like elements shown in Fig. 1 are omitted.
[0070] The image forming apparatus 1 includes the dehumidifier 13 having the inlet port
16 and the exhaust port 17a, a plurality of imaging units 14a to 14d connected to
the dehumidifier 13 via the air flow path 24, and an exhaust port 17b that exhausts
exhaust air from the imaging units 14a to 14d via the exhaust path.
[0071] The imaging units 14a to 14d includes photoconductors 31a to 31d that transfer primary
color images respectively different from each other, image transfer units 32a to 32d,
developing units 33a to 33d, cleaning units 34a to 34d, and toner supply units 35a
to 35d.
[0072] The imaging units 14a to 14d can provide a color imaging system having photoconductors
31a to 31d, to which dehumidified air is supplied from the dehumidifier 13, with the
foreign matter therein being removed.
[0073] In the fourth embodiment, since the air in the dehumidified air flow path is dehumidified,
changes in the characteristic values (hardness, Young's modulus, and the like) of
rubber parts in the image forming apparatus 1, changes in electric charges of the
developer, and changes in toner properties (fluidity and the like) can be reduced.
Accordingly, in the color imaging system having the photoconductors 31a to 31d, a
difference in the transferred images of the respective imaging systems can be reduced,
and out of color registration can be reduced, thereby achieving high quality of images.
[0074] The action and effects described in the above embodiments are only the most suitable
ones achieved by the invention, and are not limited to those described in the embodiments.
[0075] A fifth embodiment in which the present invention is applied to a full color printer
(hereinafter, "printer"), which is the image forming apparatus, is explained. Fig.
10 is a schematic block diagram of the inner configuration of the printer. As shown
in Fig. 10, the printer includes process cartridges 102Y, 102C, 102M, and 102K, which
are the imaging units for imaging respective color toner images of yellow (Y), cyan
(C), magenta (M), and black (K), in an apparatus body 101. Hereinafter, subscripts
Y, C, M, and K at the end of respective reference numbers indicate that these are
members for yellow, cyan, magenta, and black. An intermediate transfer unit 104 having
an intermediate transfer belt 103, to which toner images formed by the respective
process cartridges 102 are transferred, is provided below the respective process cartridges
102.
Below the intermediate transfer unit 104, a fixing apparatus 105, which is the fixing
unit that fixes the toner image on the transfer paper P, and a transport unit 106
that transports the transfer paper P to the fixing apparatus are provided. The fixing
apparatus 105 includes a heating roller 105a having a heat source (not shown) therein,
and a pressure roller 105b pressed against the heating roller 105a, and hence, the
fixing apparatus 105 is a heat source that generates heat most in the apparatus. A
paper feed cassette 107 for storing the transfer paper P, which can be pulled out,
is provided in the lower part of the apparatus body 101.
[0076] The respective process cartridges 102Y, 102C, 102M, and 102K respectively include
a drum-like photoconductor 110Y, 110C, 110M, or 110K, a charging roller 111Y, 111C,
111M, or 111K that charges the photoconductor 110, a development apparatus 112Y, 112C,
112M, or 112K that develops a latent image formed on the photoconductor 110, and a
cleaning blade 113Y, 113C, 113M, or 113K that cleans residual toner on the photoconductor
110. Furthermore, the respective process cartridges 102Y, 102C, 102M, and 102K respectively
include an optical unit (not shown) that can irradiate laser beams to the photoconductor
110Y, 110C, 110M, or 110K.
[0077] The process for obtaining a color image in the printer having such a configuration
is explained. At first, in the process cartridge 102Y, 102C, 102M, 102K, the photoconductor
110Y, 110C, 110M, 110K is uniformly charged by the charging roller 111Y, 111C, 111M,
111K. Thereafter, the laser beams are scanned and exposed by the optical unit based
on the image information, to form a latent image on the surface of the photoconductor
110Y, 110C, 110M, 110K. The latent image on the photoconductor 110Y, 110C, 110M, 110K
is developed by the respective color toners carried on the developing roller in the
development apparatus 112Y, 112C; 112M, 112K, to become a visible image as a toner
image. The toner images on the photoconductors 110Y, 110C, 110M, and 110K are sequentially
overlapped and transferred onto the intermediate transfer belt 103. On the other hand,
the transfer paper P in the paper feed cassette 107 is transported into the apparatus
body 101 by a paper feed roller 108 arranged near the paper feed cassette 107, and
transported to a secondary transfer unit at predetermined timing by a resist roller
pair 109. In the secondary transfer unit, the toner image formed on the intermediate
transfer belt 103 is transferred onto the transfer paper P. The transfer paper P onto
which the toner image is transferred is transported by the transport unit 106, passes
between the heating roller 105a and the pressure roller 105b in the fixing apparatus
105, thereby performing image fixation, and the transfer paper P is ejected outside
of the apparatus body.
[0078] In the printer according to the fifth embodiment, a temperature/humidity detector
120, which is the temperature/humidity detector that detects temperature and humidity
in the apparatus body 101, is provided above the black process cartridge 102K, which
is located at the furthest position from the fixing apparatus 105 as the heat source,
among the process cartridges 102Y, 102C, 102M, and 102K. In the upper part of the
apparatus body 101, an air conditioner 121 is provided, which is the temperature/humidity
adjusting unit that adjusts the temperature and humidity in the ambient atmosphere
in the apparatus body 101.
[0079] As shown in Fig. 11, a controller 122 that controls the operation of the air conditioner
121 based on the detection result of the temperature/humidity detector 120 so that
the temperature and the humidity in the apparatus body 101 is within a predetermined
range is installed. The controller 122 reads the temperature detected by the temperature/humidity
detector at predetermined timing, to determine whether the detected temperature is
within the predetermined range. When the detected temperature is within the predetermined
range, the controller 122 stops the operation of the air conditioner 121. When the
detected temperature is not within the predetermined range, the controller 122 operates
the air conditioner 121 so as to control the temperature and humidity in the apparatus
body 101 to be within the predetermined range. The controller 122 can be provided
exclusively for the control of the air conditioner 121, or can be a controller that
can control the whole image forming process. A part to be air-conditioned by the air
conditioner 121 is desirably formed substantially in a closed configuration. While
the part to be air-conditioned is the entire part of the apparatus body 101, the configuration
can be such that each process cartridge 102Y, 102C, 102M, 102K that is most likely
to be affected by the temperature and humidity can be individually air-conditioned.
[0080] Fig. 12 is a schematic block diagram of the inner configuration of a printer according
to another embodiment. In Fig. 12, like parts as in Fig. 10 are denoted by like reference
signs, and the explanation thereof is omitted. As shown in Fig. 12, a temperature/humidity
detector 123, which is the temperature/humidity detector that detects temperature
and humidity in the process cartridge 102, can be provided above the black process
cartridge 102K, which is located at the furthest position from the fixing apparatus
105, among the process cartridges 102Y, 102C, 102M, and 102K. In the upper part of
the apparatus body 101, an air conditioner 124 is provided, which is the temperature/humidity
adjusting unit that adjusts the temperature and humidity in the ambient atmosphere
in the process cartridges 102Y, 102C, 102M, and 102K. Also in this case, the controller
122 reads the temperature detected by the temperature/humidity detector 123 at predetermined
timing, to determine whether the detected temperature is within the predetermined
range. When the detected temperature is within the predetermined range, the controller
122 stops the operation of the air conditioner 124. When the detected temperature
is not within the predetermined range, the controller 122 operates the air conditioner
124 so as to control the temperature and humidity in the process cartridges 102Y,
102C, 102M, and 102K to be within the predetermined range.
[0081] The process cartridges 102Y, 102C, 102M, and 102K, which are the part to be air-conditioned
by the air conditioner 124 is desirably formed substantially in a closed configuration.
For example, the configuration is such that a part of a side plate of the process
cartridge 102, which is the incident range of the laser beams from the optical unit,
is formed of a transparent window, and only the secondary transfer unit for transferring
the toner image on the photoconductor 110 onto the transfer material is opened. An
inlet port and an exhaust port connected to the air conditioner 124 are then formed
in the process cartridge 102.
[0082] For the air conditioners 121 and 124, a desiccant air conditioner or an air conditioner
using a Peltier element can be used. Fig. 13 depicts the configuration of the desiccant
air conditioner. As shown in Fig. 13, a desiccant air conditioner 130 includes a desiccant
rotor 131 rotating in a direction of arrow A, a heater 132, and a fan 133. In the
lower part of the desiccant rotor 131, conditioned air from a part to be air-conditioned
passes from a direction of arrow B, and at this time, moisture is absorbed by the
desiccant rotor 131 and passes in a direction of arrow C, and dried conditioned air
is supplied by the fan 133 in a direction of arrow D, to be returned to the part to
be air-conditioned. On the other hand, in the upper part of the desiccant rotor 131,
moisture in the desiccant rotor 131 is removed by the heater 132, and high moisture
is discharged in a direction of arrow E toward a radiator or the outside of the apparatus.
The desiccant air conditioner 130 can realize a small size and low noise, as compared
to an air conditioner using a compressor.
[0083] Fig. 14 depicts the configuration of an air conditioner using the Peltier element.
As shown in Fig. 14, an air conditioner 140 using the Peltier element is configured
such that a Peltier element 141, whose one surface becomes low temperature and the
other surface becomes high temperature according to the flowing direction of the electric
current, is put between heat exchanger plates of a fin unit 142 on the heat absorbing
side and a fin unit 143 on the heat generating side. In the fin unit 142 on the heat
absorbing side, the conditioned air is allowed to flow in a direction of arrow F and
cooled by a fan 144, and the moisture is removed as dew condensation. In the fin unit
143 on the heat generating side, the heated conditioned air is cooled by a fan 146.
The air conditioner 140 using the Peltier element 141 can realize a small size and
low noise, as compared to an air conditioner using a compressor.
[0084] While the temperature/humidity detectors 120 and 123 preferably detect both temperature
and humidity individually, at least one of temperature and humidity need only to be
detected. Also, in the air conditioners 121 and 124, while it is preferable that both
temperature and humidity can be individually controlled, at least one of temperature
and humidity need only to be controlled. For example, the relation between the temperature
and saturated water vapor content is as shown in Fig. 15. Therefore, for example,
the saturated water vapor content at 40°C is 51.2 g/m
2, and at this time, if the water vapor content is 11.4 g/m
2, the relative humidity becomes 11.2/51.2x100%=22%. When the temperature is 25°C,
the saturated water vapor content is 22.8 g/m
2, and the relative humidity becomes 11.4/22.8x100%=50%. Accordingly, by controlling
the temperature, the humidity can be controlled.
[0085] In the printer according to the fifth embodiment, the temperature/humidity detector
120 is installed near the black process cartridge 120K located at the furthest position
from the fixing apparatus 105, among the process cartridges 102Y, 102C, 102M, and
102K. Therefore, the temperature/humidity detector 120 can detect temperature and
humidity in the ambient atmosphere in the apparatus body 101, in the state that the
temperature/humidity detector 120 is hardly affected directly by the heat from the
fixing apparatus 105, as compared to an instance in which the temperature/humidity
detector 120 is installed near the process cartridge 102Y, 102C, or 102M.
[0086] In the printer according to the fifth embodiment, the temperature/humidity detector
123 is installed in the black process cartridge 102K located at the furthest position
from the fixing apparatus 105, among the process cartridges 102Y, 102C, 102M, and
102K. Since parts in the printer that are apt to be affected by temperature and humidity
are provided in the process cartridge 102 in a centralized manner, it is required
to detect accurately the temperature and humidity in the ambient atmosphere in the
process cartridge 102. When the temperature/humidity detector 123 is installed in
the process cartridge 102K, the temperature and humidity in the ambient atmosphere
in the process cartridge 102K can be detected more accurately, than in the instance
in which the temperature/humidity detector 123 is installed outside the process cartridge
102K.
[0087] Furthermore, in the process cartridge 102 having the photoconductor 110, which performs
development, charging, and cleaning, the influence of humidity is large, and hence,
it is desired to control the humidity (relative humidity) to be equal to or lower
than a certain value. In the black process cartridge 102K located at the furthest
position from the fixing apparatus 105, if the relative humidity can be set equal
to or lower than the certain value, in the process cartridges 102Y, 102C, and 102M
close to the fixing apparatus 105, the relative humidity becomes lower than that of
the black process cartridge 102K, due to the heat from the fixing apparatus 105. In
other words, if the relative humidity is controlled in the black process cartridge
102K located at the furthest position from the fixing apparatus 105, the relative
humidity is inevitably maintained to be equal to or lower than the certain value in
the other process cartridges 102Y, 102C, and 102M.
Accordingly, it is not necessary to install the temperature/humidity detector 120
or 123 in the respective process cartridges 102Y, 102C, and 102M, and only one temperature/humidity
detector 120 or 123 can serve the function.
[0088] By making the color of the process cartridge located at the furthest position from
the heat source black, the temperature and humidity of the black process cartridge
102K having the highest use frequency can be controlled most accurately.
[0089] In general, the part generating heat most in the printer is the fixing apparatus
that performs fixation by thermo compression bonding. Therefore, by installing the
temperature/humidity detector 120, 123 at a position away from the fixing apparatus
105, the temperature/humidity detector 120, 123 is hardly affected by the heat from
the fixing apparatus 105.
[0090] The desiccant air conditioner 130 and the air conditioner 140 using the Peltier element
can realize a small size and low noise, as compared to the air conditioner using a
compressor.
[0091] Although the invention has been described with respect to a specific embodiment for
a complete and clear disclosure, the appended claims are not to be thus limited but
are to be construed as embodying all modifications and alternative constructions that
may occur to one skilled in the art that fairly fall within the basic teaching herein
set forth.
1. An image forming apparatus (1) comprising:
a flow path forming member that forms a dehumidified air flow path (A) and an exhaust
heat air flow path (B);
a dehumidifier (13) including
a cooling-and-dehumidifying member (11) positioned in the dehumidified air flow path
(A), and
a heat exhaust member (12) positioned in the exhaust heat air flow path (B);
a case (15) that covers an aperture common to the dehumidified air flow path (A) and
the exhaust heat air flow path (B); and
an imaging unit (14) connected to the dehumidifier (13) by a connecting air flow path
(24) through which dehumidified air is introduced into the imaging unit (14) from
the dehumidified air flow path (A).
2. The image forming apparatus (1) according to claim 1, comprising
a Peltier element (10) positioned between the cooling-and-dehumidifying member (11)
and the heat exhaust member (12).
3. The image forming apparatus (1) according to one of claims 1 or 2, wherein the dehumidifier
(13) includes a heat exhaust fan (20) that discharges exhaust heat from the exhaust
heat air flow path (B) to outside of the image forming apparatus (1) .
4. The image forming apparatus (1) according to one of claims 1 or 2, wherein the dehumidifier
(13) includes a dehumidifying fan (21) provided in front of the cooling-and-dehumidifying
member (11).
5. The image forming apparatus (1) according to one of claims 1 or 2, wherein the connecting
air flow path (24) includes a member that filters out foreign partiales (18).
6. The image forming apparatus (1) according to claim 1, wherein the exhaust heat air
flow path (B) includes a member that filters out foreign particies (18a).
7. The image forming apparatus (1) according to one of claims 1 or 2, wherein the dehumidifier
(13) includes a member that filters out foreign particles (27, 27a) from both the
dehumidified air flow path (A) and the exhaust heat air flow path (B).
8. The image forming apparatus (1) according to one of claims 1 to 2, wherein the exhaust
heat air flow path (B) includes an absorption/diffusion member (25) that stores dehumidified
water.
9. The image forming apparatus (1) according to one of claims 1 or 2, wherein the imaging
unit (14) includes a photoconductor (31) and an image transfer unit (32) adjacent
to the photoconductor (31).
10. The image forming apparatus (1) according to one of claims 1 or 2, wherein the imaging
unit (14) is a process cartridge (102)in which a photoconductor (31) and an image
transfer unit (32) adjacent to the photoconductor (31) are integrally combined.
11. The image forming apparatus (1) according to one of claims 1 or 2, wherein the imaging
unit (14) includes transfer paper (28), a transfer paper transport unit (29), and
a transfer paper Container (26).
12. The image forming apparatus (1) according to one of claims 1 or 2, wherein the imaging
unit (14) includes a color imaging mechanism having independent photoconductors (31).
13. The image forming apparatus (1) according to one of claims 1 or 2, wherein the imaging
unit (14) includes
a humidity detector (8) that detects a relative humidity in the imaging unit (14),
wherein
the dehumidifier (13) dehumidifies air in the dehumidified air flow path (A) when
the humidity detected by the humidity detector (8) is a predetermined value or more
and supplies dehumidified air to the imaging unit (14) from the case (15).
14. The image forming apparatus (1) according to claim 5, wherein the imaging unit (14)
includes a dust-proof construction in which the dehumidified air introduced from the
connecting air flow path (24) is discharged to a downstream exhaust path (23).
15. The image forming apparatus (1) according to claim 3, wherein the dehumidified air
seht from the dehumidifying fan (21) is introduced to the imaging unit (14) through
the cooling-and-dehumidifying member (11).
16. An air intake and exhaust System comprising:
a flow path forming member that forms a dehumidified air flow path (A) and an exhaust
heat air flow path (b)
a dehumidifier (13) including
a cooling-and-dehumidifying member (11) positioned in the dehumidified air flow path
(A), and
a heat exhaust member (12) positioned in the exhaust heat air flow path (B);
an inlet port (16) to which the dehumidifier (13) is connected;
a case (15) that covers an aperture common to the dehumidified air flow path (A) and
the exhaust heat air flow path (B);
a connecting air flow path (24) through which dehumidified air is introduced into
an imaging unit (14) from the dehumidified air flow path (A);
a dehumidifying fan (21) that sends an air flow from the dehumidified air flow path
(A) to the connecting air flow path (24); and
a heat exhaust fan (20) that discharges exhaust heat from the exhaust heat air flow
path (B) to outside.
17. The air intake and exhaust System according to claim 16, wherein the dehumidifier
(13) includes a water absorption member (25) integrally provided in the dehumidified
air flow path (A).
18. The air intake and exhaust System according to claim 16, wherein the dehumidifier
(13) evaporates dehumidified water in the exhaust heat air flow path (B).
19. The air intake and exhaust system according to claim 16, wherein the dehumidifier
(13) includes a water absorption/diffusion member (25) integrally provided in the
exhaust heat air flow path (B), and the dehumidifier (13) ventilates the exhaust heat
to the water absorption/diffusion member (25) containing dehumidified water to evaporate
the dehumidified water.
20. The air intake and exhaust system according to one of claims 16 to 19 comprising:
a Peltier element (10) positioned between the cooling-and-dehumidifying member (11)
and the heat exhaust member (12).
21. An image forming apparatus (1) comprising:
a plurality of imaging units (14) that forms a toner image on an image carrier;
a temperature/humidity detector (120, 123) that detects temperature and humidity in
the image forming apparatus (1);
a temperature/humidity adjusting unit that adjusts temperature and humidity in the
image forming apparatus (1) ;
a controller (122) that controls the temperature/humidity adjusting unit based an
a detection result of the temperature/humidity detector (120, 123) to adjust temperature
and humidity to a predetermined range; and
a heat source that generates highest temperature in the image forming apparatus (1),
wherein
the temperature/humidity detector (120, 123) is located near one of the imaging units
(14) located furthest from the heat source.
22. The image forming apparatus (1) according to claim 21, wherein:
a temperature/humidity adjusting unit adjusts temperature and humidity in at least
one of or in each of the imaging units (14).
23. The image forming apparatus (1) according to one of claims 21 or 22, wherein the temperature/humidity
detector (120, 123) is located near or in one of the imaging units (14) located furthest
from the heat source, and not near any of the other imaging units (14).
24. The image forming apparatus (1) according to one of claims 21 or 22, wherein the imaging
unit (14) furthest from the heat source contains a black toner.
25. The image forming apparatus (1) according to one of claims 21 or 22, wherein the heat
source is a fixing unit that fixes the toner image on a transfer material by thermo
compression bonding.
26. The image forming apparatus (1) according to one of claims 21 or 22, wherein the temperature/humidity
adjusting unit is a desiccant air conditioner.
27. The image forming apparatus (1) according to one of claims 21 or 22, wherein the temperature/humidity
adjusting unit is an air conditioner using a Peltier element (10).