JP5887509B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus, it is known that several kinds of chemical substances are released from the image forming apparatus during image formation. Typical chemical substances to be released include ozone generated when the photosensitive drum is charged, and toner dust generated during development or fixing. Conventionally, measures such as providing a filter have been taken in order to prevent such generated chemical substances from being released outside the image forming apparatus.

  For example, a volatile chemical substance collection device in an electronic device disclosed in Patent Document 1 generates an electric field in an atmosphere from an electric field generation / collection member in an exhaust duct provided at an upper portion of a fixing unit, and the action of the electric field Volatile organic compounds (VOC) contained in the atmosphere are attracted to the surface of the electric field generating and collecting member and collected.

  Further, the image forming apparatus disclosed in Patent Document 2 is provided with a duct having an intake port for taking in fine particles generated from a heating roller in the fixing device in the vicinity of the fixing device. An exhaust fan that generates an air flow from the intake port to the outlet is provided in the extended portion of the duct, and a first filter member is provided upstream of the exhaust fan. The first filter member captures ultrafine particles (for example, siloxane) generated from the rubber layer constituting the fixing device. In addition, a shutter that closes the gap between the first filter member and the expansion unit is provided, and the control unit of the image forming apparatus has a state in which the shutter closes the first filter unit according to a predetermined initial burst condition. The shutter is switched between a state where the shutter does not block the first filter portion.

  Further, in the odor removing apparatus in the composite image forming apparatus of Patent Document 3, a plurality of gas passage portions for guiding gas into the housing are formed at the bottom of the housing. Each gas passage section is a cylindrical body having an inner diameter on the upper side inside the casing smaller than the inner diameter of the casing bottom, and an ozone decomposition filter including an ozone decomposition catalyst is disposed on the inner diameter surface of the cylindrical body. A waste liquid absorber is disposed on the bottom of the housing, a deodorizing adsorbent is disposed on the upper lid in the housing, and a gas passing between the waste liquid absorber and the deodorizing adsorbent is disposed on the side of the housing. An exhaust port is provided.

JP 2009-282455 A JP 2011-180235 A JP 2011-180283 A

  By the way, recently, with the growing awareness of environmental protection around the world, fine particles (for example, ultra fine particles (UFP: Ultrafine Particles having a particle size of 100 nm or less) different from ozone and the like are generated from an electrophotographic image forming apparatus. To do so has become a problem.

However, as a structure for capturing ultrafine particles, for example, an electronic device shown in Patent Document 1, an additional volatile chemical substance collecting device that attracts and collects volatile organic compounds to the surface of the electric field generating and collecting member can be added. In this case, there arises a problem that the structure becomes complicated.
Further, for example, as in the image forming apparatus shown in Patent Document 2, if a first filter member capable of capturing particulates is provided on the upstream side of the exhaust fan, and the exhaust gas is transmitted through the first filter member, The first filter member increases the resistance during air conveyance, the exhaust efficiency decreases, and the temperature inside the housing rises. For this reason, the output of the exhaust fan has to be increased, and there arises a problem that there is a concern about generation of noise and an increase in running cost.
Furthermore, if a plurality of dedicated odor removing devices (for example, two in Patent Literature) are added as in the composite image forming device shown in Patent Literature 3, for example, the structure becomes complicated and the cost of the device cannot be avoided. There is a problem.

  SUMMARY OF THE INVENTION In order to solve the above-described conventional problems, an object of the present invention is to provide an image forming apparatus that has a simple structure, reduces the discharge amount of ultrafine particles, and suppresses an increase in the output of an exhaust fan.

  The present invention provides a fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet, and a direction along the axis of the heating roller. A duct that is disposed in the vicinity of the fixing device along the axis of the heating roller and is exhausted by an exhaust fan provided at one end in the longitudinal direction, and a duct on the fixing device side of the duct. An exhaust port that is opened in the first side wall and communicates with the fixing device and the duct; and a planar filter that is attached to an inner wall surface of the duct, the surface of the filter extending in a longitudinal direction of the duct On the other hand, in the image forming apparatus, grooves and protrusions extending in an oblique direction are uneven surfaces alternately arranged in the longitudinal direction of the duct.

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the exhaust gas is increased, the probability of capturing ultrafine particles is improved, and the amount of ultrafine particles discharged outside the image forming apparatus is reduced. Can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclined direction (hereinafter referred to as a “separated inclination direction”) in which the inclined end of one end side (exhaust fan side) in the duct longitudinal direction of the groove portion and the protruding portion is separated from the first side wall. On the other hand, the other is an inclination direction in which the inclined end of the groove portion and the protruding portion on the exhaust fan side approaches the first side wall (hereinafter referred to as “approach inclination direction”).
Further, the exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of flow of the exhaust gas is gradually bent from the exhaust port and is changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
Exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction can easily contact the exhaust gas over the entire length in the extending direction. As a result, the time for the exhaust gas to contact the groove portion and the ridge portion in the direction of the separating inclination becomes long.
On the other hand, the exhaust immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust gas tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  The present invention provides a fixing device including a heating roller and a pressure roller for heating and pressing a paper carrying an unfixed toner image and fixing the unfixed toner image on the paper, and a fixing device containing the fixing device. A housing chamber, and a duct that is formed in a length in a direction along the axis of the heating roller with a part of a wall portion in the fixing device housing chamber as a first side wall, and is exhausted by an exhaust fan provided at one end in the longitudinal direction. An exhaust port that is opened in the first side wall and communicates with the fixing device housing chamber and the duct; and a planar filter that is attached to an inner wall surface of the duct. In the image forming apparatus, grooves and ridges extending obliquely with respect to the longitudinal direction are uneven surfaces alternately arranged in the longitudinal direction of the duct.

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the housing chamber exhaust is increased, the capture probability of the ultrafine particles is improved, and the ultrafine particles are discharged out of the image forming apparatus. The amount can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclined direction (separated inclination direction) in which the inclined end of the groove portion and the protruding portion on one end side in the longitudinal direction of the duct (exhaust fan side) is separated from the first side wall. On the other hand, the other is an inclination direction (approaching inclination direction) in which the inclined end of the groove portion and the protruding portion on the exhaust fan side approaches the first side wall.
In addition, the housing chamber exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of the flow of the storage chamber exhaust gas is gradually bent from the exhaust port and changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
The containment chamber exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction are easy to contact the storage chamber exhaust over the entire length in the extending direction. As a result, the groove portion and the ridge portion in the separating inclination direction have a longer time for the accommodation chamber exhaust to contact.
On the other hand, the exhaust in the storage chamber immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust in the storage chamber tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  Since the duct also serves as a part of the wall of the fixing device housing chamber, the image forming apparatus can be easily manufactured. Further, since the duct is disposed adjacent to the fixing device housing chamber along the pressure roller, no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  According to another aspect of the present invention, there is provided a fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet, and an axis of the heating roller. A duct that is formed in a longitudinal direction along the axis of the heating roller and that is disposed in the vicinity of the fixing device and is exhausted by an exhaust fan provided at one end in the longitudinal direction; and the fixing device of the duct An exhaust port that is opened in the first side wall on the side and communicates with the fixing device and the duct; and a planar filter that is attached to the inner wall surface of the duct in parallel with the inner wall surface, The surface of the filter is an image forming apparatus in which grooves and ridges extending in an oblique direction with respect to the longitudinal direction of the duct are concave and convex surfaces alternately arranged in the longitudinal direction of the ceiling surface of the duct. .

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the exhaust gas is increased, the probability of capturing ultrafine particles is improved, and the amount of ultrafine particles discharged outside the image forming apparatus is reduced. Can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclination direction (separation inclination direction) in which an inclined end of one end side in the longitudinal direction of the duct (exhaust fan side) of the groove portion and the protrusion portion located on the ceiling surface is separated from the first side wall. The other is an inclination direction (approaching inclination direction) in which the inclined end of the groove portion and the protruding portion on the exhaust fan side of the ridge portion approaches the first side wall.
Further, the exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of flow of the exhaust gas is gradually bent from the exhaust port and is changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
Exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction can easily contact the exhaust gas over the entire length in the extending direction. As a result, the time for the exhaust gas to contact the groove portion and the ridge portion in the direction of the separating inclination becomes long.
On the other hand, the exhaust immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust gas tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  The planar filter is attached in parallel to the inner wall surface of the duct. By arranging the filter in parallel with the inner wall surface, it is possible to easily fix the filter directly to the inner wall surface using an adhesive, a double-sided adhesive tape, or the like. In the duct, the filter is directly fixed to the inner wall surface, so that the reduction of the air conveyance space is minimized.

  The present invention further includes a fixing device including a heating roller and a pressure roller for heating and pressing a paper carrying an unfixed toner image and fixing the unfixed toner image on the paper, and the fixing device. The fixing device housing chamber and a part of the wall portion of the fixing device housing chamber are formed as a first side wall in a length direction along the axis of the heating roller, and are exhausted by an exhaust fan provided at one end in the longitudinal direction. A duct, an exhaust port that is opened in the first side wall and communicates with the fixing device housing chamber and the duct, and a planar filter that is attached to the inner wall surface of the duct in parallel to the inner wall surface; The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct. Forming equipment .

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the housing chamber exhaust is increased, the capture probability of the ultrafine particles is improved, and the ultrafine particles are discharged out of the image forming apparatus. The amount can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclination direction (separation inclination direction) in which an inclined end of one end side in the longitudinal direction of the duct (exhaust fan side) of the groove portion and the protrusion portion located on the ceiling surface is separated from the first side wall. The other is an inclination direction (approaching inclination direction) in which the inclined end of the groove portion and the protruding portion on the exhaust fan side of the ridge portion approaches the first side wall.
In addition, the housing chamber exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of the flow of the storage chamber exhaust gas is gradually bent from the exhaust port and changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
The containment chamber exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction are easy to contact the storage chamber exhaust over the entire length in the extending direction. As a result, the groove portion and the ridge portion in the separating inclination direction have a longer time for the accommodation chamber exhaust to contact.
On the other hand, the exhaust in the storage chamber immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust in the storage chamber tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  Since the duct also serves as a part of the wall of the fixing device housing chamber, the image forming apparatus can be easily manufactured. Further, since the duct is disposed adjacent to the fixing device housing chamber along the pressure roller, no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  The planar filter is attached in parallel to the inner wall surface of the duct. By arranging the filter in parallel with the inner wall surface, it is possible to easily fix the filter directly to the inner wall surface using an adhesive, a double-sided adhesive tape, or the like. In the duct, the filter is directly fixed to the inner wall surface, so that the reduction of the air conveyance space is minimized.

  Further, the present invention provides a fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet, and an axis of the heating roller. A duct that is formed in a longitudinal direction along the axis of the heating roller and that is disposed in the vicinity of the fixing device and is exhausted by an exhaust fan provided at one end in the longitudinal direction; and the fixing device of the duct An exhaust port that is open in the first side wall and communicates with the fixing device and the duct; and a planar filter that is attached to the inner ceiling surface of the duct in parallel with the ceiling surface. The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct. so That.

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the exhaust gas is increased, the probability of capturing ultrafine particles is improved, and the amount of ultrafine particles discharged outside the image forming apparatus is reduced. Can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclination direction (separation inclination direction) in which an inclined end of one end side in the longitudinal direction of the duct (exhaust fan side) of the groove portion and the protrusion portion located on the ceiling surface is separated from the first side wall. The other is an inclination direction (approaching inclination direction) in which the inclined end of the groove portion and the protruding portion on the exhaust fan side of the ridge portion approaches the first side wall.
Further, the exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of flow of the exhaust gas is gradually bent from the exhaust port and is changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
Exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction can easily contact the exhaust gas over the entire length in the extending direction. As a result, the time for the exhaust gas to contact the groove portion and the ridge portion in the direction of the separating inclination becomes long.
On the other hand, the exhaust immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust gas tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  In addition, by installing the filter in parallel to the ceiling surface of the duct, it is possible to effectively bring the exhaust gas containing water vapor generated at the time of fixing the paper and ultrafine particles having buoyancy caused by the rising air current into contact with the filter. It becomes possible. In particular, since the exhaust immediately after the exhaust fan is stopped stays in the vicinity of the ceiling surface after moving at a low flow rate, ultrafine particles can be captured efficiently.

  The present invention further includes a fixing device including a heating roller and a pressure roller for heating and pressing a paper carrying an unfixed toner image and fixing the unfixed toner image on the paper, and the fixing device. The fixing device housing chamber and a part of the wall portion of the fixing device housing chamber are formed as a first side wall in a length direction along the axis of the heating roller, and are exhausted by an exhaust fan provided at one end in the longitudinal direction. A duct, an exhaust port that is opened in the first side wall and communicates with the fixing device housing chamber and the duct, and a planar filter that is attached to the ceiling surface inside the duct in parallel with the ceiling surface. And the surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct. , Image forming equipment It is.

  In the configuration described above, the duct is disposed in the vicinity of the fixing device along the axis of the heating roller, so that no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  In addition, since the filter is configured to be long along the longitudinal direction of the duct, the contact time with the housing chamber exhaust is increased, the capture probability of the ultrafine particles is improved, and the ultrafine particles are discharged out of the image forming apparatus. The amount can be reduced. Further, since the filter does not cross the air conveyance space of the duct, unlike the conventional transmission type filter, an increase in resistance during the air conveyance can be suppressed, in other words, an increase in the output of the exhaust fan can be suppressed.

Moreover, a groove part and a protrusion part are extended in the diagonal direction with respect to the longitudinal direction of a duct. “Inclined with respect to the longitudinal direction of the duct” is considered to be two inclined directions. One is an inclination direction (separation inclination direction) in which an inclined end of one end side in the longitudinal direction of the duct (exhaust fan side) of the groove portion and the protrusion portion located on the ceiling surface is separated from the first side wall. The other is an inclination direction (approaching inclination direction) in which the inclined end of the groove portion and the protruding portion on the exhaust fan side of the ridge portion approaches the first side wall.
In addition, the housing chamber exhaust flowing in the air conveyance space of the duct toward the exhaust fan first flows into the duct in a direction orthogonal to the longitudinal direction of the duct from the exhaust port of the first side wall. That is, the direction of the flow of the storage chamber exhaust gas is gradually bent from the exhaust port and changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.
The containment chamber exhaust gas immediately after flowing in from the exhaust port is likely to flow downstream without being countered along the extending direction of the groove portion and the ridge portion when the groove portion and the ridge portion are in the separating inclination direction. Therefore, the groove portion and the ridge portion in the separating inclination direction are easy to contact the storage chamber exhaust over the entire length in the extending direction. As a result, the groove portion and the ridge portion in the separating inclination direction have a longer time for the accommodation chamber exhaust to contact.
On the other hand, the exhaust in the storage chamber immediately after flowing in from the exhaust port is likely to hit from a direction substantially orthogonal to the extending direction of the protrusion when the groove and the protrusion are in the approaching inclination direction. That is, the exhaust in the storage chamber tends to generate a turbulent flow by colliding with the ridge, and many vortices are generated in the vicinity of the filter. As a result, the probability that the ultrafine particles are trapped in the minute gaps of the filter itself is improved in the grooves and protrusions in the approaching inclination direction.
It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan which of the approaching inclination direction and the separating inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion and the ridge portion in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  Since the duct also serves as a part of the wall of the fixing device housing chamber, the image forming apparatus can be easily manufactured. Further, since the duct is disposed adjacent to the fixing device housing chamber along the pressure roller, no useless space is generated in the image forming apparatus. As a result, the configuration of the image forming apparatus itself is simple and compact. Further, the filter can be easily replaced, and the maintainability of the image forming apparatus can be improved.

  Further, since the filter is installed in parallel with the ceiling surface of the duct, the storage chamber exhaust containing water vapor generated at the time of fixing the paper and ultrafine particles generated by buoyancy due to the rising airflow is effectively brought into contact with the filter. It becomes possible. In particular, since the storage chamber exhaust immediately after the exhaust fan stops stays in the vicinity of the ceiling surface after moving at a low flow rate, ultrafine particles can be efficiently captured.

  Furthermore, the present invention is an image forming apparatus in which a plurality of the exhaust ports are formed in the longitudinal direction of the first side wall.

  In the configuration described above, there are a plurality of exhaust ports, and the interval and area of each exhaust port are appropriately set, so that the exhaust duct that flows into the air conveyance space of the duct is compared with the case where there is one exhaust port. Variations in the inflow amount in the longitudinal direction can be suppressed.

  Furthermore, the present invention is an image forming apparatus in which a transmission type filter that allows exhaust from the fixing device to pass is attached to an exhaust opening surface of the exhaust fan.

  In the configuration described above, the exhaust gas including the exhaust from the fixing device passes through the air conveyance space of the duct and is exhausted from the exhaust opening surface of the exhaust fan in a state where ultra fine particles are reduced. At this time, the exhaust passes through the transmission type filter, so that the remaining ultrafine particles are further captured. The transmission type filter is provided over the entire cross section of the duct, so that ultrafine particles can be captured supplementarily.

  According to the present invention, the discharge amount of ultrafine particles can be reduced with a simple structure, and the increase in the output of the exhaust fan can be suppressed.

Longitudinal sectional view of the MFP of this embodiment The perspective view which looked at the 1st side wall of the multifunctional machine shown in FIG. 1 from the fixing device storage chamber side FIG. 2 is a perspective view in which FIG. 2 is cut out at a substantially central position in the longitudinal direction of the heating roller. 3 is a perspective view looking up from below the duct side. The perspective view which looked at the exhaust port of the 1st side wall from the upper part in the state which omitted illustration of the duct ceiling surface Perspective view of filter Perspective view of transmissive filter

  Hereinafter, an embodiment of an image forming apparatus according to the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings. In the following embodiment, an electrophotographic multifunction peripheral will be described as an example of an image forming apparatus according to the present invention. However, the image forming apparatus according to the present invention is not limited to a multifunction peripheral, and may be a copying machine or a printer, for example.

  FIG. 1 is a longitudinal sectional view of a multifunction machine 11 according to this embodiment. FIG. 2 is a perspective view of the first side wall 57 of the multifunction machine 11 shown in FIG. 1 as viewed from the fixing device housing chamber 51 side. FIG. 3 is a perspective view of FIG. 2 cut out at a substantially central position in the longitudinal direction of the heating roller 41. 4 is a perspective view of FIG. 3 as viewed from below the duct 53 side. FIG. 5 is a perspective view of the exhaust port 63 of the first side wall 57 as seen from above with the duct ceiling surface 71 not shown. FIG. 6 is a perspective view of the filter 65. FIG. 7 is a perspective view of the transmission filter 85.

  The multifunction machine 11 of the present embodiment has functions such as a scanner, a copy, and a printer, for example, and based on print job data input from an external device (for example, a PC (Personal Computer (not shown))), a sheet (for example, a recording material) Alternatively, a single-color or multi-color image is formed (fixed) on a recording sheet and discharged.

  1 includes a photosensitive drum 13, a charger 15, a developing roller 17, a transfer roller 19, an exposure device 21, a fixing device 23, and a paper feeding cassette (main unit casing 31). (Not shown), a paper transport roller 25, a paper discharge roller 27, and a paper discharge tray 29.

  For example, a set of visible image forming units (process units) 33 is disposed at a substantially central position in the main body casing 31 of the multifunction machine 11 shown in FIG. For the sake of simplicity, the multifunction machine 11 shown in FIG. 1 will be described assuming that a set of visible image forming units 33 for forming a black image, for example, is disposed. A visible image forming unit having a similar configuration may be arranged for each (yellow, magenta, cyan).

  The visible image forming unit 33 is provided with a photosensitive drum 13 that serves as a carrier for an electrostatic latent image corresponding to print job data input to the multifunction machine 11, and around the photosensitive drum 13, A charger 15, a developing roller 17, a transfer roller 19, and a cleaning unit 35 are disposed.

  The charger 15 uniformly charges the surface of the photosensitive drum 13 to a predetermined potential (for example, a negative potential). The charger 15 is preferably of a charging roller type that can uniformly charge the surface of the photosensitive drum 13 without generating ozone as much as possible when charging the photosensitive drum 13, for example. However, the charger 15 is not limited to the charging roller type, and for example, a contact brush or a non-contact charger type may be used.

  The developing roller 17 visualizes the electrostatic latent image formed on the photosensitive drum 13 by the exposure device 21 described later using the toner supplied to the developing roller 17. As a result, a toner image corresponding to the print job data is obtained. In this embodiment, for example, black toner is supplied to the developing roller 17. The multi-function device 11 may be supplied with toner of each color to each developing roller of the visible image forming unit having the same configuration as the visible image forming unit 33 corresponding to each color of yellow, magenta, and cyan.

  The transfer roller 19 is disposed so as to face the photosensitive drum 13, and transfers the toner image formed on the surface of the photosensitive drum 13 onto the paper 37 conveyed along the paper conveyance path 45. Hereinafter, the toner image transferred onto the sheet 37 by the transfer roller 19 is referred to as an “unfixed toner image”.

  The cleaning unit 35 removes and collects the toner remaining on the surface of the photosensitive drum 13 after the transfer process in the transfer roller 19.

  The exposure apparatus 21 includes a laser scanning unit 39 (LSU: Laser Scanning Unit). The laser scanning unit 39 includes a laser light source, a polygon mirror that scans laser light emitted from the laser light source, and a lens that guides the laser light scanned by the polygon mirror to the photosensitive drum 13 and a reflection mirror. . The laser scanning unit 39 exposes the surface of the photosensitive drum 13 with light from the polygon mirror according to the input print job data, and forms an electrostatic latent image on the photosensitive drum 13 according to the print job data. .

  The fixing device 23 includes a heating roller 41 and a pressure roller 43 that extend perpendicularly to the paper 37. The heating roller 41 is heated to a predetermined target temperature (for example, a fixing temperature within a range of 180 to 200 ° C.) by a heater as a heating source. The pressure roller 43 is urged toward the heating roller 41 by a spring (not shown). The fixing device 23 fixes the unfixed toner image on the paper 37 by heating and pressurizing the paper 37 on which the toner image is transferred by the pressure roller 43 and the heating roller 41.

  In the main casing 31, a paper transport path 45 is formed between a paper feed cassette (not shown) and the paper discharge tray 29. The sheet conveyance path 45 is configured by a conveyance path from the sheet conveyance roller 25, between the photosensitive drum 13 and the transfer roller 19, and through the fixing device 23 to the sheet discharge roller 27 (in FIG. 1). (See arrow A). The paper transport path 45 becomes a paper discharge path 47 immediately before the paper discharge roller 27. The paper discharge path 47 is provided with a switchback conveyance path (not shown) for sending the paper 37 again to the position of the transfer roller 19 in, for example, double-sided printing.

  Furthermore, a control unit (not shown) for controlling the overall operation of the multifunction machine 11 is provided in the main body casing 31. The control unit is configured using a processor (for example, a central processing unit (CPU), a micro processing unit (MPU), or a digital signal processor (DSP)). The control unit performs operations of each unit of the multifunction machine 11, that is, each operation of the photosensitive drum 13, the charger 15, the developing roller 17, the transfer roller 19, the exposure device 21, the fixing device 23, the paper transport roller 25, and the paper discharge roller 27. Control. The control unit also controls the operation of an exhaust fan 49 (see FIG. 2) described later.

  In the multifunction machine 11 having the above-described configuration, the image forming process is performed as follows by the control unit of the multifunction machine 11.

  At the time of image formation, first, paper 37 is sent out one by one from a paper feed cassette (not shown) to a paper transport path 45 by a paper transport roller 25.

  After the charger 15 uniformly charges the surface of the photosensitive drum 13, the exposure device 21 uses a laser beam in accordance with print job data input from an external device to scan the charged area on the surface of the photosensitive drum 13. Exposure. As a result, an electrostatic latent image corresponding to the print job data is formed on the surface of the photosensitive drum 13. Subsequently, the developing roller 17 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 13 using the toner supplied by the developing roller 17. As a result, a toner image corresponding to the print job data is obtained.

  Further, the transfer roller 19 transfers the toner image formed on the surface of the photosensitive drum 13 onto the paper 37 that has been fed from the paper feed cassette (not shown) by the paper transport roller 25 and transported. As a result, an unfixed toner image corresponding to the print job data is transferred onto the paper 37. The unfixed toner image transferred onto the paper 37 is conveyed to the fixing device 23. The fixing unit 23 heats and presses the unfixed toner image sufficiently with the heating roller 41 and the pressure roller 43 to fix it on the paper 37. As a result, an image corresponding to the print job data is formed on the paper 37, and the paper 37 is discharged to the paper discharge tray 29 by the paper discharge roller 27.

  Here, in the multifunction machine 11 of the present embodiment, a fixing device storage chamber 51 for storing the fixing device 23 is provided around the fixing device 23. The fixing device accommodating chamber 51 is formed as a cavity having an airtightness so that ultra fine particles (UFP) generated in the fixing device accommodating chamber 51, that is, the ultrafine particles (UFP) generated in the fixing device 23 do not leak outside the fixing device accommodating chamber 51. The

  More specifically, the fixing device housing chamber 51 is formed by connecting a plurality of sheet metal materials and molded resin plates fixed to the main body casing 31. Since the fixing device accommodating chamber 51 becomes negative pressure by the suction of an exhaust fan 49 described later, the presence of a small gap of about the paper conveyance path 45 leading to the outside of the cavity is allowed. Further, the fixing device accommodating chamber 51 is not evacuated by the outside air flowing from these gaps. The fixing device accommodating chamber 51 may be provided with a dedicated air supply port.

  Further, a duct 53 is provided adjacent to the fixing device housing chamber 51. The duct 53 is formed to be long in the direction along the axis 59 (see FIG. 2) of the heating roller 41, and is disposed in the vicinity of the fixing device 23 along the axis 59 of the heating roller 41. More specifically, the duct 53 is formed to be long in the direction along the axis 59 (see FIG. 2) of the heating roller 41 with a part of the wall portion 55 in the fixing device housing chamber 51 as a first side wall 57. . An exhaust fan 49 (see FIG. 2) is provided at one end side in the longitudinal direction of the duct 53, and the exhaust fan 49 removes exhaust gas containing air present in the air conveyance space 61 (see FIG. 1) of the duct 53 of the main casing 31. Exhaust outwards.

  An exhaust port 63 (see FIG. 2) is opened in the first side wall 57 of the duct 53 on the fixing device 23 side, that is, the first side wall 57 of the wall portion 55 of the fixing device housing chamber 51. The exhaust port 63 allows the fixing device 23 and the duct 53 to communicate with each other. More specifically, the exhaust port 63 communicates the fixing device housing chamber 51 provided so as to cover the fixing device 23 and the duct 53. In the present embodiment, as shown in FIG. 2, a plurality of (two in FIG. 2) exhaust ports 63 are formed in the longitudinal direction of the first side wall 57. The intervals and opening areas of the respective exhaust ports 63 are set after adjustment in the longitudinal direction of the fixing device storage chamber 51 so that the storage chamber exhaust 87 described later is exhausted without variation.

  A planar filter 65 is detachably attached to the inner wall surface of the duct 53 in parallel with the inner wall surface. The inner wall surface of the duct 53 is used as a general term for the duct ceiling surface 71, the first side wall 57, the second side wall 73, and the bottom wall 75. As shown in FIG. 6, the filter 65 holds the filter main body 67 inside the frame body 69. The filter 65 is detachably attached to the duct 53 when the frame body 69 is held or released from a holding portion (not shown) such as a locking structure and a rail provided inside the duct 53. .

  The duct 53 is formed with a ceiling surface (duct ceiling surface 71) of the rectangular duct 53 whose inner wall surface is along the longitudinal direction of the duct 53. The filter 65 is attached to the duct ceiling surface 71, and specifically, is preferably installed in a rectangular shape that covers the duct ceiling surface 71. As long as the filter 65 has an area covering most of the duct ceiling surface 71 as a result, the filter 65 may be divided into a plurality of parts instead of a single one.

  In addition to the duct ceiling surface 71, the filter 65 may be installed on the first side wall 57, the second side wall 73, and the bottom wall 75 so as to cover all or a part thereof. However, when the filter 65 is provided on the first side wall 57, the filter 65 is provided at a portion other than the exhaust port 63 so as not to block the exhaust port 63.

  The duct ceiling surface 71 is formed with an upward slope that becomes higher as the distance from the exhaust port 63 increases. The second side wall 73 opposite to the first side wall 57 across the duct ceiling surface 71 has an acute angle with the duct ceiling surface 71.

  As shown in FIG. 6, the surface of the filter 65 has parallel grooves 77 and protrusions 79 extending obliquely with respect to the longitudinal direction of the duct 53, and the longitudinal direction of the duct ceiling surface 71 (the arrow in FIG. 6). It is formed to have uneven surfaces 81 that are alternately arranged in the (B direction). Since the filter 65 has the uneven surface 81, the surface area increases.

  In addition, the groove part 77 and the protrusion part 79 which comprise the uneven surface 81 are good also as various shapes. For example, although not shown, the groove 77 can be a V-groove and the protrusion 79 can be an inverted V-shaped chevron. Although not shown in the drawings, the groove 77 and the ridge 79 may form a so-called sine wave shape in which the bottom of the V groove and the top of the inverted V-shaped chevron are curved. . Further, although not shown, the groove 77 and the ridge 79 may be a concave groove having a flat groove bottom and a convex ridge 79 having a flat top.

  In this embodiment, the transmission type filter 85 shown in FIGS. 5 and 7 is attached so as to cover the exhaust opening surface 83 (see FIG. 2) of the exhaust fan 49. As shown in FIG. 7, the surface of the transmission filter 85 is also formed to have an uneven surface 81 in which parallel groove portions 77 and protrusions 79 are alternately arranged. The transmissive filter 85 has an uneven surface 81, thereby increasing the surface area. The transmission filter 85 allows the storage chamber exhaust 87 (described later) flowing in through the exhaust port 63 to pass therethrough. Similar to the filter 65, the transmission filter 85 is also detachably attached to the exhaust opening surface 83.

Next, the operation of the multifunction machine 11 having the above-described configuration will be described.
In the multifunction machine 11, an unfixed toner image corresponding to print job data input from an external device is transferred onto the paper 37 and conveyed to the fixing device 23. In the fixing device 23, the paper 37 is sandwiched between the heating roller 41 and the pressure roller 43. The unfixed toner image carried on the sheet 37 is fixed as an image fused to the sheet 37 by the heating by the heating roller 41 and the pressing by the pressure roller 43.

  At this time, it is known that a very small amount of toner constituting the unfixed toner image is separated from the unfixed toner image together with water vapor in the fixing device 23 as the moisture contained in the paper 37 evaporates. Generally, a toner is configured using a pigment, a wax, and an external additive. The external additive improves the reaction efficiency with static electricity as a main effect, and is used by attaching fine particles such as silica to the toner surface. In recent years, it has been reported that an external additive that separates together with water vapor is considered to be one of the factors that increase ultrafine particles (UFP) in the multifunction machine 11.

  In the present embodiment, the external additive separated from the toner surface is transported to the upper portion of the fixing device housing chamber 51 together with the air that is moved by natural convection and the suction force of the exhaust fan 49 together with the water vapor generated when the paper 37 is fixed. . A first side wall 57, which is a part of the wall portion 55, is provided above the fixing device housing chamber 51. The first side wall 57 serves as a partition wall with the duct 53 provided adjacent to the fixing device housing chamber 51. The duct 53 is formed long in the direction along the axis 59 of the heating roller 41. In other words, the duct 53 is arranged in parallel and adjacent to the fixing device 23 and the partition wall, so that the compactness of the multifunction machine 11 is realized. An exhaust port 63 is formed in the first side wall 57 that is a partition wall, and the exhaust port 63 is located inside the fixing device housing chamber 51, that is, the exposure space of the fixing device 23 and the inside of the duct 53 (the air conveyance space 61). And communicate with each other.

  The duct 53 causes the air in the air transport space 61 to flow toward one end in the longitudinal direction by an exhaust fan 49 provided on one end in the longitudinal direction. As a result, the air inside the fixing device housing chamber 51 is sucked and flows into the air conveyance space 61 of the duct 53 having a negative pressure through the exhaust port 63. The external additive (ultrafine particle: UFP) separated from the toner surface together with water vapor generated when fixing the paper 37 is mostly sucked air (hereinafter referred to as “container exhaust”) together with other volatile organic compounds (VOC) and dust. And flows into the air conveyance space 61 of the duct 53.

  The housing chamber exhaust 87 shown in FIGS. 2 and 3 comes into contact with the surface of the planar filter 65 attached in parallel to the inner wall surface of the duct 53 when being transferred to one end in the longitudinal direction of the duct 53. It has been confirmed that the ultrafine particles (UFP) contained in the storage chamber exhaust 87 are captured by the filter 65 due to the contact between the filter 65 and the storage chamber exhaust 87. Specifically, it can be confirmed by measuring the discharge amount of ultrafine particles on the outlet side of the exhaust fan 49 when the filter 65 is provided in the duct 53 and when the filter 65 is not provided. The action of the ultrafine particles captured by the filter 65 arranged in parallel with the storage chamber exhaust 87 is that the storage chamber exhaust 87 becomes a turbulent flow in the vicinity of the surface of the filter 65, resulting in a vortex. It may be caught on the surface of the filter 65, that is, captured.

  The filter 65 can use vegetable fiber, mineral fiber, synthetic fiber, woven fabric, non-woven fabric, felt, knitted fabric, resin foam, porous film, or the like as a base material. Regardless of which substrate is used, the surface of the filter 65 is configured with a large number of microvoids, that is, fiber gaps and pores.

  The storage chamber exhaust 87 flowing through the air transfer space 61 of the duct 53 is a uniform flow at a position far from the filter 65 and has no speed gradient (speed change). On the other hand, since there is no slip on the surface of the filter 65, a region in the vicinity of the surface of the filter 65 is formed where the flow rate continuously changes due to the influence of frictional force and leads to a uniform flow. That is, the surface of the filter 65 is covered with a thin layer (boundary layer) having a large velocity gradient. It is considered that the ultrafine particles whose carrier energy is reduced by the boundary layer and the above-described vortex caused by the turbulent flow are caught by being caught in the minute gap on the filter surface. Note that the boundary layer is changed by ultrafine particles (UFP) trapped and deposited. Note that there seems to be an optimum value for the correlation between the ultrafine particles (UFP) and the size of the microvoids and the flow velocity of the containment chamber exhaust 87.

  As described above, in this embodiment, the duct 53 is disposed in the vicinity of the fixing unit 23 along the axis 59 of the heating roller 41, so that no useless space is generated in the multifunction machine 11. As a result, the configuration itself of the multifunction machine 11 is simple and compact.

  More specifically, in this embodiment, since the duct 53 also serves as a part of the wall portion 55 of the fixing device housing chamber 51, the multifunction machine 11 can be easily manufactured. Further, since the duct 53 is arranged adjacent to the fixing device housing chamber 51 along the heating roller 41 with only a partition wall therebetween (no parallel space), no useless space is generated in the multifunction machine 11. As a result, the configuration itself of the multifunction machine 11 is simple and compact. In addition, the filter 65 can be easily replaced, and the maintainability of the multifunction machine 11 can be improved.

  In addition, since the filter 65 is configured to be long along the longitudinal direction of the duct 53, the contact time with the housing chamber exhaust 87 is increased, the probability of capturing ultrafine particles (UFP) is improved, and the ultrafine particles (UFP) are increased. ) To the outside of the multifunction machine 11 can be reduced. Further, the filter 65 does not cross the air conveyance space 61 of the duct 53 and is installed in the air conveyance space 61 in parallel with the conveyance direction of the storage chamber exhaust 87. Thereby, unlike the conventional transmission filter, the filter 65 can suppress an increase in resistance during air conveyance, in other words, an increase in the output of the exhaust fan.

  Further, in the multi-function device 11, the filter 65 is installed on the duct ceiling surface 71, so that the storage chamber exhaust 87 including water vapor generated when the paper 37 is fixed and ultra fine particles (UFP) in which buoyancy is generated by the rising airflow. Can be effectively brought into contact with the filter 65. In particular, the containment chamber exhaust 87 immediately after the exhaust fan 49 is stopped stays in the vicinity of the duct ceiling surface 71 after moving at a low flow rate, so that ultrafine particles (UFP) can be efficiently captured.

  Further, in the multi-function device 11, the duct ceiling surface 71 has an upward slope that becomes higher as the distance from the exhaust port 63 increases, and the included angle between the second side wall 73 and the duct ceiling surface 71 becomes an acute angle. For this reason, the air conveyance space 61 sandwiched between the second side wall 73 and the filter 65 becomes a corner space that is gradually narrowed upward. In this corner space, due to the frictional force of the second side wall 73 and the filter 65, the flow speed during exhausting decreases toward the far side farther from the exhaust fan 49. In addition, it is expected that the storage chamber exhaust 87 including the ultrafine particles (UFP) that has risen together with the water vapor rises toward the corner space. Thereby, ultrafine particles (UFP) can be deposited on the filter 65 from the back side of the corner space. As a result, the surface of the filter 65 can be used efficiently from the back side of the corner space.

  Further, in the multifunction machine 11, a filter 65 having a concavo-convex surface 81 in which grooves 77 and protrusions 79 are alternately arranged is installed in the conveying direction of the storage chamber exhaust 87. The accommodation chamber exhaust 87 to be conveyed repeatedly collides with the groove portion 77 and the protruding portion 79 to generate a vortex. Thereby, the filter 65 can improve the probability of trapping ultrafine particles (UFP) in the minute gaps of the filter 65 itself.

  Further, in the multifunction machine 11, there are a plurality of exhaust ports 63, and the interval and area of each exhaust port 63 are set appropriately. Thereby, compared with the case where the number of the exhaust ports 63 is one, the dispersion | variation in the inflow amount in the longitudinal direction of the duct 53 of the storage chamber exhaust 87 which flows in into the air conveyance space 61 of the duct 53 can be suppressed.

  Further, in the multi-function device 11, the storage chamber exhaust 87 containing the exhausted matter from the fixing device 23 passes through the air conveyance space 61 of the duct 53, so that the ultrafine particles (UFP) are reduced in the exhaust fan 49. The air is exhausted from the exhaust opening surface 83. At this time, the storage chamber exhaust 87 containing the exhaust from the fixing device 23 passes through the transmission filter 85, so that the remaining ultrafine particles are further captured. The transmission filter 85 is provided over the entire cross section of the duct 53, so that ultrafine particles can be captured supplementarily. The filter 65 and the transmission filter 85 in the duct 53 can be installed by appropriately adjusting the filter capacity. For example, the filter 65 in the duct 53 may have a long replacement time, and the transmission filter 85 may have a short replacement time.

  Here, if a conventional configuration in which the filter 65 is not provided in the duct 53 is considered, the reduction of ultrafine particles (UFP) depends only on the transmission filter 85. In this case, if the transmission filter 85 is made thicker in order to improve the trapping performance of ultra fine particles (UFP), the exhaust fan 49 having a larger output is required, and therefore noise increases.

  On the other hand, in the multi-function device 11 according to the present embodiment in which the duct 53 includes the filter 65, the transmission filter 85 may have any auxiliary performance. Therefore, the multifunction machine 11 of the present embodiment does not increase the air resistance even when the transmission filter 85 is attached, and can suppress an increase in the output of the exhaust fan 49.

In the filter 65, the groove 77 and the protrusion 79 extend in an oblique direction with respect to the longitudinal direction of the duct 53. “Inclined with respect to the longitudinal direction of the duct 53” may be two inclined directions. One is an inclination direction (separation inclination direction) in which the inclined end of the groove 77 and the protrusion 79 located on the duct ceiling surface 71 on one end side in the longitudinal direction of the duct (exhaust fan 49 side) is separated from the first side wall 57. is there. On the other hand, on the contrary, the groove 77 located on the duct ceiling surface 71 and the inclined end of the ridge 79 on the exhaust fan 49 side are in an inclination direction (approaching inclination direction) approaching the first side wall 57. is there.
In addition, the storage chamber exhaust gas 87 flowing in the air conveyance space 61 of the duct 53 toward the exhaust fan 49 first flows into the duct 53 from the exhaust port 63 of the first side wall 57 in a direction orthogonal to the longitudinal direction of the duct 53. . That is, the direction of the flow of the storage chamber exhaust gas 87 is gradually bent from the exhaust port 63 and is changed to a right angle direction. Strictly speaking, it is a complex three-dimensional streamline that interferes with each other.

The storage chamber exhaust 87 immediately after flowing in from the exhaust port 63 is downstream without being countered along the extending direction of the groove 77 and the ridge 79 when the groove 77 and the ridge 79 are in the “separated inclination direction”. It becomes easy to flow. Therefore, the groove portion 77 and the protruding portion 79 in the separating inclination direction facilitate the contact of the containing chamber exhaust 87 over the entire length in the extending direction. As a result, the groove 77 and the protrusion 79 in the direction of separating inclination increase the time for the accommodation chamber exhaust 87 to contact.
On the other hand, the storage chamber exhaust 87 immediately after flowing in from the exhaust port 63 is easy to hit from a direction substantially perpendicular to the extending direction of the protrusion 79 when the groove 77 and the protrusion 79 are in the “approaching inclination direction”. Become. In other words, the containment chamber exhaust 87 is likely to generate turbulent flow by colliding with the protrusion 79, and many vortices are generated in the vicinity of the filter 65. As a result, the probability that the grooves 77 and the protrusions 79 in the approaching inclination direction trap ultrafine particles in the minute gaps of the filter 65 itself is improved.

  It can be confirmed by measuring the discharge amount of the ultrafine particles on the outlet side of the exhaust fan 49 which of the approaching inclination direction and the separation inclination direction can capture more ultrafine particles. As a result of confirmation, it has been found that the groove portion 77 and the protruding portion 79 in the approaching inclination direction have a higher capture rate of ultrafine particles than in the separating inclination direction.

  While various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  INDUSTRIAL APPLICABILITY The present invention is useful as an image forming apparatus that has a simple structure, reduces the discharge amount of ultrafine particles, and suppresses an increase in the output of an exhaust fan.

11 MFP 23 Fixing device 37 Paper 41 Heating roller 43 Pressure roller 49 Exhaust fan 51 Fixing device housing chamber 53 Duct 55 Wall portion 57 First side wall 59 Axis 63 Exhaust port 65 Filter 71 Duct ceiling surface (ceiling surface of the duct)
73 Second side wall 77 Groove portion 79 Projection portion 81 Uneven surface 83 Exhaust opening surface 85 Transmission type filter

Claims (8)

A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A duct that is formed in a length in a direction along the axis of the heating roller, is disposed in the vicinity of the fixing device along the axis of the heating roller, and is exhausted by an exhaust fan provided at one end in the longitudinal direction;
An exhaust port that is opened in a first side wall of the duct on the side of the fixing unit, and communicates the fixing unit and the duct;
A planar filter attached to the inner wall surface of the duct,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the duct.
Image forming apparatus. A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A fixing device storage chamber for storing the fixing device;
A duct that is formed in a length in a direction along the axis of the heating roller with a part of the wall portion in the fixing device housing chamber as a first side wall, and is exhausted by an exhaust fan provided on one end side in the longitudinal direction;
An exhaust port that is opened in the first side wall and communicates the fixing device housing chamber and the duct;
A planar filter attached to the inner wall surface of the duct,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the duct.
Image forming apparatus. A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A duct that is formed in a length in a direction along the axis of the heating roller, is disposed in the vicinity of the fixing device along the axis of the heating roller, and is exhausted by an exhaust fan provided at one end in the longitudinal direction;
An exhaust port that is opened in a first side wall of the duct on the side of the fixing unit, and communicates the fixing unit and the duct;
A planar filter attached to the inner wall surface of the duct in parallel with the inner wall surface,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct.
Image forming apparatus. A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A fixing device storage chamber for storing the fixing device;
A duct that is formed in a length in a direction along the axis of the heating roller with a part of the wall portion in the fixing device housing chamber as a first side wall, and is exhausted by an exhaust fan provided on one end side in the longitudinal direction;
An exhaust port that is opened in the first side wall and communicates the fixing device housing chamber and the duct;
A planar filter attached to the inner wall surface of the duct in parallel with the inner wall surface,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct.
Image forming apparatus. A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A duct that is formed in a length in a direction along the axis of the heating roller, is disposed in the vicinity of the fixing device along the axis of the heating roller, and is exhausted by an exhaust fan provided at one end in the longitudinal direction;
An exhaust port that is opened in a first side wall of the duct on the side of the fixing unit, and communicates the fixing unit and the duct;
A planar filter attached to the ceiling surface inside the duct in parallel to the ceiling surface,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct.
Image forming apparatus. A fixing device including a heating roller and a pressure roller for heating and pressing a sheet carrying an unfixed toner image and fixing the unfixed toner image on the sheet;
A fixing device storage chamber for storing the fixing device;
A duct that is formed in a length in a direction along the axis of the heating roller with a part of the wall portion in the fixing device housing chamber as a first side wall, and is exhausted by an exhaust fan provided on one end side in the longitudinal direction;
An exhaust port that is opened in the first side wall and communicates the fixing device housing chamber and the duct;
A planar filter attached to the ceiling surface inside the duct in parallel to the ceiling surface,
The surface of the filter is an uneven surface in which grooves and ridges extending obliquely with respect to the longitudinal direction of the duct are alternately arranged in the longitudinal direction of the ceiling surface of the duct.
Image forming apparatus. The image forming apparatus according to any one of claims 1 to 6,
A plurality of the exhaust ports are formed in the longitudinal direction of the first side wall,
Image forming apparatus. The image forming apparatus according to any one of claims 1 to 7,
A transmission type filter that allows exhaust from the fixing device to pass through is attached to the exhaust opening surface of the exhaust fan.
Image forming apparatus.

Images