JP2010032620A - Recording material conveying device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an image quality difference between in a portion coming in contact with a conveying means and a portion not coming in contact with the conveying means, in the case where a recording material heated by a thermal fixing device is conveyed by the conveying means that partly comes in contact with the recording material. <P>SOLUTION: The printing paper discharged from the thermal fixing device 105 is sucked and conveyed by the conveying belt 302a having a plurality of holes formed therein with the suction force of a suction fan 105. With this constitution, the air sucked by the suction fan 105 is made to circulate in a cavity located on the conveying surface side of the conveying belt 302a by means of a duct 306. Thus, the image quality difference between the portion coming in contact with the conveying belt 302a and the hole portions not coming in contact with the conveying belt is suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording material conveying apparatus and an image forming apparatus.

  Patent Document 1 describes a technology of a fixing unit in which a suction fan that adsorbs a sheet discharged from the fixing unit to a carry-out belt is disposed inside a conveyance belt for conveying the sheet discharged from the fixing unit. ing.

JP 2004-198863 A

  In the present invention, when the recording material heated by the heat fixing device is conveyed by a conveying means that contacts a part of the recording material, the recording material is fixed to the recording material by a portion that is in contact with the conveying means and a portion that is not in contact with the recording material. The purpose is to provide a technique for suppressing the difference in image quality.

  According to a first aspect of the present invention, there is provided a conveying unit that contacts a part of the recording material heat-fixed by the heating fixing unit and conveys the recording material, and a section in which the conveying unit and the recording material are in contact with each other. A suction means for sucking air on a surface side where the recording material comes into contact with the transport means, an air path portion constituting a path through which air sucked by the suction means flows, and the air path portion are provided in the air path. A recording material conveying apparatus comprising: a conveyance surface side discharge port through which the air flowing through the portion is discharged to a conveyance surface side where the conveyance means contacts the recording material.

  According to a second aspect of the present invention, in the first aspect of the present invention, the transport surface side discharge port is a transport surface discharge port through which the transport means discharges air toward a transport surface that contacts the recording material. It is characterized by being.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the air path portion discharges air in a direction intersecting with the conveyance direction of the recording material on the downstream side of the conveyance unit in the conveyance direction. A downstream discharge port is provided.

  Invention of Claim 4 is provided with the water vapor | steam removal means which removes the water vapor | steam in the said air path part in the invention as described in any one of Claims 1-3.

  According to a fifth aspect of the present invention, there is provided an image forming means for forming an image on a recording material, a heat fixing means for heat fixing the image formed by the image forming means on the recording material, and any one of the first to fourth aspects. The recording material conveying apparatus according to claim 1 and a cooling means for cooling the recording material conveyed by the conveying means, and on the image surface side of the recording material on which the image is heated and fixed by the heat fixing means In the image forming apparatus, no contact is made between the heat fixing unit and the cooling unit.

  According to the first aspect of the present invention, when the recording material heated by the heat fixing device is conveyed by the conveying means that contacts a part of the recording material, the portion that contacts the conveying means and the portion that does not contact A difference in image quality fixed on the recording material can be suppressed.

  According to the second aspect of the present invention, as compared with the case where the second aspect of the invention is not used, the state of adsorption of the recording material to the conveying means is stabilized.

  According to the third aspect of the present invention, the temperature of the air on the conveying surface side of the conveying means is suppressed from lowering than when the invention according to the third aspect is not used.

  According to the invention described in claim 4, it is possible to suppress the dew condensation with the recording material as compared with the case where the invention described in claim 4 is not used.

  According to the invention described in claim 5, it is possible to suppress the image formed on the recording material from being disturbed as compared with the case where the invention described in claim 5 is not used.

Hereinafter, an embodiment using the invention will be described.
(Outline of the embodiment)
In the embodiment described below, an example of a recording material conveyance device disposed on the downstream side of the heat fixing unit and an example of an image forming apparatus including the recording material conveyance device are shown. FIG. 1 shows an image forming apparatus 100. The image forming apparatus 100 is configured to form an image on a recording material, the image forming unit 10 used as an image forming unit in the present embodiment, and the image formed in the image forming unit 10 is heated and fixed. A heat fixing device 105 used as a heat fixing unit in the embodiment, a conveying device 106 used as a recording material conveying device in the present embodiment, and a cooling device 107 used as a cooling unit in the present embodiment are provided.

  1 to 4 show conveying belts 302a and 302 used as conveying means in this embodiment. The conveyor belts 302a and 302b are in contact with a part of the heat-fixed recording material and convey the recording material. Also shown is an intake fan 305 used as suction means in the present embodiment. The suction fan 305 sucks the air on the surface side in contact with the conveyance belts 302a and 302b of the recording material. The air path portion may be constituted by a wall surface, but the duct 306 is used as the air path portion in the present embodiment. The duct 306 serves as a path for sending the air sucked by the intake fan 305 to the conveying surface side of the conveying belts 302a and 302b. Here, the cooling device 107 cools the recording material conveyed by the conveyance belt 302a.

(Configuration of image forming apparatus)
An image forming apparatus 100 illustrated in FIG. 1 includes a recording material storage device 101. In this example, a printing paper 102 which is an example of a recording material is stored in the recording material storage device 101. As the recording material, in addition to paper, resin-made materials such as OHP paper can be used.

  A transport roller mechanism 104 that transports the printing paper discharged from the recording material storage device 101 is disposed downstream of the recording material storage device 101. An image forming unit 10 having a function of forming a toner image on printing paper is disposed on the downstream side of the transport roller mechanism 104. Here, the downstream side refers to the downstream side of the processing flow when viewed in time series. On the other hand, on the upstream side, this means, on the contrary, the upstream side of the processing flow.

  A heat fixing device 105 for heat fixing the toner image formed on the printing paper onto the printing paper is disposed on the downstream side of the image forming unit 10. On the downstream side of the heat fixing device 105, a transport device 106 that transports the printing paper discharged from the heat fixing device 105 toward a cooling device 107 described later is disposed. The transport device 106 includes a transport belt 302a that transports the recording material.

  A cooling device 107 for cooling the printing paper is disposed on the downstream side of the conveying device 106. The printing paper cooled in the cooling device 107 is discharged to a discharge unit (not shown).

  The heat fixing device 105 includes a heater and becomes high temperature. When the heat fixing device becomes high temperature, the surrounding air becomes high temperature and high humidity. When this high-temperature and high-humidity air flows into the cooling device 107, the cooling device 107 may be warmed to reduce the cooling capacity, or condensation may occur on the printing paper. Conversely, when the air from the cooling device 107 flows in, the heating capability of the heat fixing device may decrease. In this embodiment, compared with the case where there is no distance between the heat fixing device and the cooling device, the distance between the heat fixing device and the cooling device is increased to make it difficult for air to flow in and out. A portion where the distance between the heat fixing device and the cooling device is increased conveys the printing paper by the conveying device 106.

(Configuration of image forming unit)
Hereinafter, the configuration of the image forming unit 10 in FIG. 1 will be described. The image forming unit 10 includes four image forming units 10Y to 10M for forming toner images of basic colors of YMCK on printing paper.

  Since the basic structures of the image forming units 10Y to 10M are the same, the configuration of the image forming unit 10Y will be described below as a representative. The image forming unit 10 </ b> Y includes a photosensitive drum 11. The photosensitive drum 11 rotates in the direction of the arrow in the figure (counterclockwise direction). A cleaning roll 12 for removing toner remaining on the surface of the photosensitive drum 11 is disposed on the photosensitive drum 11. The exposure device 13 irradiates the surface of the photosensitive drum 11 on the downstream side (counterclockwise direction in the drawing) of the cleaning roll 12 while scanning with laser light for forming an electrostatic latent image. A charging device (not shown) for charging the photosensitive drum 11 is disposed between the portion where the exposure is performed and the cleaning roll 12.

  A toner supply device 14 for supplying toner to the surface of the photosensitive drum 11 on which the latent image is formed by exposure is disposed downstream of the exposed portion of the photosensitive drum 11. Further, on the downstream side, a transfer roll 15 is disposed so as to face the photosensitive drum 11. The above is the configuration of the image forming unit 10Y. The image forming units 10M to 10K have the same basic structure except that the toner used is different.

(Operation of image forming unit)
Hereinafter, operations of the image forming units 10Y to 10K will be described. Since the operations of the image forming units 10Y to 10K are basically the same except for the color of the toner, the operation of the image forming unit 10Y will be described as a representative here.

  In the state where the photosensitive drum 11 is rotating in the counterclockwise direction in the figure, the toner remaining on the surface is removed from the cleaning roll 12. The portion from which the residual toner has been removed is charged with a charge from a charging device (not shown), and further irradiated with a laser beam from the exposure device 13 while being scanned. By this laser light irradiation, the surface of the photosensitive drum 11 is exposed in a state corresponding to the image pattern formed, and an electrostatic latent image is formed.

  Y toner is supplied from the toner supply device 14 to the portion where the electrostatic latent image is formed, and Y toner adheres to the surface of the photosensitive drum 11 in accordance with the charge distribution constituting the electrostatic latent image. . Thus, a Y-color toner image is formed on the photosensitive drum 11. The printing paper discharged from the recording material storage device 101 is transported between the photosensitive drum 11 and the transfer roll 15 in accordance with the toner image formation timing, and the printing paper is sandwiched between the two. The toner image on the photosensitive drum 11 is transferred onto the printing paper. The surface of the photosensitive drum 11 on which the toner image has been transferred is cleaned by a cleaning roll 12. By repeating the above operation, a Y-color toner image is formed on the printing paper conveyed on the conveyance path 103.

  The above is the operation of forming the Y-color toner image in the image forming unit 10Y. In the image forming units 10M to 10K, the toner image of each basic color is formed by the same operation. In this way, the color toner images are formed by sequentially superimposing the YMCK basic color toner images on the printing paper conveyed in the right direction in the drawing along the conveyance path 103.

(Configuration of heat fixing device)
Next, the configuration of the heat fixing device 105 will be described. The heat fixing device 105 includes a heat roll 201 and a pressure roll 202 facing the heat roll 201. The heat roll 201 includes a heater inside and generates heat. Reference numeral 203 denotes a fixing belt, which is stretched between the heat roll 201 and the drive roll 204. A belt cleaning roll 205 that cleans the surface of the fixing belt 203 is in contact with the fixing belt 203. Further, the fixing belt 203 is in a state of receiving pressure from the pressure roll 202 at the portion of the heat roll 201.

(Operation of heat fixing device)
Next, the operation of the heat fixing device 105 will be described. When the drive roll 204 rotates counterclockwise in the figure, the fixing belt 203 rotates counterclockwise. In this process, the printing paper conveyed through the conveyance path 103 from the left in the figure is fixed to the fixing belt 203 and the pressure. It is sandwiched between the roll 202. At this time, the toner image formed on the printing paper is heated by the fixing belt 203 and simultaneously pressed. By applying the pressure while being heated, the toner image formed on the printing paper is fixed.

(Conveyor configuration)
Next, the configuration of the transport device 106 shown in FIG. 1 will be described. The transport device 106 includes a transport belt unit 300. As shown in FIG. 1, the transport device 106 has a box-shaped housing 309 having an inlet and an outlet for transporting printing paper. A part or all of the housing 309 may be a wall surface constituted by another member. Note that when the housing 309 is present, the inflow and outflow of air from the heat fixing device and the cooling device is suppressed as compared with the case without the housing 309.

  FIG. 2 is a perspective view showing an outline of the conveyor belt unit 300. As shown in FIG. 2, the conveyance belt unit 300 has a drive roll 303 and a guide roll 304 attached to a housing 301, and a conveyance belt 302 a and a conveyance belt 302 b are stretched between the drive roll 303 and the guide roll 304. Yes.

  FIG. 2 shows a gear 305 attached to one end of the drive roll 303. A drive gear (not shown) is engaged with the gear 305, and a drive force from a motor (not shown) is transmitted to the drive gear, whereby the drive roll 303 is driven. Then, as the drive roll 303 rotates, the conveyor belts 302a and 302b rotate.

  A number of holes 30 are formed in the transport belt 302a. Similarly, a large number of holes 31 are formed in the transport belt 302b. The printing paper does not come into contact with the holes 30 or 31 of the conveyance belts 302a and 302b, but is conveyed in contact with a portion having no holes. An intake fan 305 that sucks air is disposed in the lower part of the center of the housing 300. The intake fan 305 has a centrifugal fan structure, and intakes air from an intake port 305a used as a suction port in the present embodiment, and exhausts air from an exhaust port 305b. When air is sucked in by the intake fan 305, air near the hole 30 formed in the transport belt 302a and the hole 31 formed in the transport belt 302b is also sucked.

  This suction causes a difference in air pressure between the air on the surface side of the printing paper that is in contact with the conveyance belt and the air on the back surface thereof, that is, on the toner image surface side, and the printing paper is attracted to the conveyance belts 302a and 302b. Then, the conveyance belts 301a and 301b rotate to convey the printing paper.

  FIG. 3 is a perspective view showing an outline of the duct. 4 is a perspective view showing a state in which the conveyance belt unit 300 and the intake fan 305 shown in FIG. 2 are combined with the duct 306 shown in FIG. Exhaust air from the intake fan 305 is sent to the duct 306. The duct 306 has a bent path for guiding the air sent from the intake fan 305 to the conveyance surface side (the surface on the Z-axis positive direction side in the figure) where the conveyance belts 302a and 302b contact the printing paper, Discharge ports 307a and 307b used as the conveyance surface side discharge ports in the embodiment are provided.

  That is, the duct 306 expands the flow of exhaust from the intake fan 305 in the width direction (Y-axis direction) with respect to the transport direction, and further bends the flow upward from both ends in the width direction (Z-axis positive direction). Configure the flow path that creates the flow. Further, the duct 306 bends the two flows whose flow directions are changed upward to the upstream side in the conveyance direction (X-axis negative direction), and the two flows are discharged from the discharge ports 307a and 307b to the conveyance belt 302a and A flow path is formed in the space on the conveyance surface side of 302b.

  The discharge ports 307a and 307b are positioned at both ends in the width direction in the direction perpendicular to the transport direction on the surface on which the printing paper is transported, and are displaced from the suction port 305a of the intake fan 305 in the transport direction, and the printing paper is transported It is shifted in the direction perpendicular to the surface to be applied, and is further located in the center of the discharge ports 307a and 307b in the width direction.

  Air sucked by the intake fan 305 is exhausted from the intake fan 305 to the duct 306. The exhaust gas passes through the duct 306 and is discharged from the discharge ports 307a and 307b to the space on the surface side of the conveyor belts 302a and 302b that contacts the printing paper.

  As shown in FIGS. 3 and 4, the duct 306 is formed with a plurality of outlets 308 used as downstream outlets in the present embodiment. Part of the air flowing in the duct 306 is discharged from the discharge port 308 toward the conveyance path 103.

  The discharge port 308 is provided between the conveyor belts 302a and 302b and the cooling device 107 (see FIG. 1). By discharging the air in the duct 306 from the discharge port 308 in a direction that blocks the air around the conveyor belt and the air around the cooling device, the air is discharged downstream of the conveyor belts 302a and 302b and upstream of the cooling device 107. In addition, a wall (air curtain) of air flowing from the lower side to the upper side is formed. This air wall becomes an obstacle when the air circulating in the transfer device 106 shown in FIG. 1 flows in the direction of the cooling device 107.

(Transfer device operation)
First, the drive roll 303 is rotated in the clockwise direction in FIG. 1, and the intake fan 305 is further operated. In this state, when the printing paper is discharged from the heat fixing device 105, the printing paper is attracted to the conveyance belts 302a and 302b, and the printing paper is downstream (in the X-axis direction) according to the rotation of the conveyance belts 302a and 302b. It is conveyed toward.

  At this time, the exhaust air from the intake fan 305 passes through the duct 306 and is discharged from the discharge ports 307a and 307b into the space above the printing paper. On the other hand, since the printing paper is heated (for example, about 70 ° C. to 90 ° C.) in the heat fixing device 105, the printing paper being conveyed in the conveying device 106 is at a temperature higher than normal temperature (temperature of the surrounding environment). Therefore, the air sucked into the intake fan 305 while the printing paper is being conveyed by the conveying belts 302a and 302b is warmed by the heat of the printing paper. This warmed air is guided by the duct 306 and discharged from the discharge ports 307a and 307b above the printing paper being conveyed.

  The printing paper discharged from the heat fixing device 105 is attracted to the rotating conveyance belts 302a and 302b on the back side (the lower side in FIG. 1) of the surface on which the image is formed, so that the right side in FIG. It is conveyed toward. Incidentally, there are cases where images are formed on both sides of the printing paper. In this case, the surface on which the image is formed means the surface heated immediately before by the downstream heat fixing device, and the image After an image is formed by the forming unit 10 and passes through the heat fixing device 105, an image is again formed on the back surface by the image forming unit 10, and when the image is heated and fixed, the surface on which the image is formed later is displayed. It is called the surface on which the image is formed. Since the printing paper has a certain degree of elasticity (strength to maintain its shape), it is separated from the conveying belts 302a and 302b on the downstream side of the conveying belts 302a and 302b, and then in the cooling device 107. By being sandwiched between the transport belts 401 and 402, the transport belt is further transported in the right direction in the figure. At this time, between the heat fixing device 105 and the cooling device 107, no member contacts the surface side on which the image of the printing paper is formed.

  Since the air discharged above the printing paper being transported is the above-described warmed air, the temperature of the atmosphere in the space above the printing paper being transported is higher than the temperature of the outside air. As a result, the temperature difference between the portion of the printing paper in contact with the conveyance belts 302a and 302b and the portion facing the numerous holes 30 and 31 is alleviated, and the traces of the shapes of the holes 30 and 31 are formed into an image. Occurrence of phenomena remaining on the surface is suppressed.

  Further, exhaust is performed upward from the exhaust port 308, and an air curtain is formed by the flow of the exhaust. This air curtain prevents the flow of air toward the cooling device 107 on the downstream side in the transport direction.

(Configuration of cooling device)
Next, the cooling device 107 will be described. As shown in FIG. 1, the cooling device 107 includes conveyance belts 401 and 402. The conveyance belt 401 and the conveyance belt 402 are in uniform contact with each other in the direction orthogonal to the conveyance direction of the printing paper, so that there is no difference between a contact portion and a non-contact portion. The conveyance belt 401 is in contact with the heat sink 403 on the surface opposite to the side in contact with the printing paper. The transport belt 401 is driven to rotate by the drive roll 404 in a state where the tension is applied by the tension roll 405.

  The conveyance belt 402 has a surface opposite to the side in contact with the printing paper pressed by a pressing roll group 406, is given tension by a tension roll 408, and is further driven by a driving roll 407 to rotate. The pressing roll group 406 presses the conveying belt 402 toward the conveying belt 401 by pressing a plurality of rolls upward (in the direction of the heat sink 403) by the repulsive force of the spring.

(Cooling device operation)
First, the conveyor belt 401 is rotated in the counterclockwise direction in the figure, and the conveyor belt 402 is rotated in the clockwise direction in the figure. In this state, the printing paper conveyed from the conveying device 106 is sandwiched between the conveying belts 401 and 402, and the printing paper is conveyed in the right direction (X-axis positive direction) in the drawing.

  At this time, the printing paper is pressed against the transport belt 401 by the function of the pressing roll group 406, and the transport belt 401 is pressed against the heat sink 403. As a result, the heat on the printing surface (the surface on which the image is formed) of the printing paper escapes to the heat sink 403 via the conveying belt 401, and the printing paper whose temperature has risen due to heating in the heat fixing device 105 is cooled. The cooled printing paper is discharged from the cooling device 107 in the right direction in the figure.

(Other shapes of ducts)
Next, another example of the duct 306 shown in FIGS. 3 and 4 will be described. FIG. 5 is a perspective view showing another example of the duct. FIG. 5 shows a structure provided with the discharge ports 310a and 310b used as the downstream discharge ports in the present embodiment. In the example shown in FIG. 5, a part of the exhaust from the intake fan 305 is discharged from the discharge ports 310 a and 301 b on the downstream side of the conveyance belts 302 a and 302 b (see FIG. 2) not shown in FIG. 5.

  The direction of the flow of air discharged from the discharge ports 310a and 301b is a direction that intersects the transport direction of the printing paper (the positive direction of the X axis in the drawing) and a direction along the surface of the printing paper. The air discharged from the discharge ports 310a and 301b also becomes an air curtain having the same function as the exhaust discharged from the discharge port 308 of FIG.

  FIG. 6 is a perspective view showing another example of the duct. FIG. 6 shows an example in which the metal plate 311 used as the water vapor removing means in the present embodiment is arranged on the inner bottom surface of the duct 306 in the configuration shown in FIG. As the metal plate 311, for example, an aluminum plate or a copper plate is used. The metal plate 311 removes water vapor by condensing moisture contained in the air flowing in the duct 306.

  Instead of the metal plate 311, a metal member provided with fins having a large surface area may be used. The water vapor removing means may use a material that adsorbs moisture known as a dehumidifying agent. Moreover, a part or front part of the duct 306 may be made of a metal material, and the inner surface (inner wall) of the duct 306 may be used as a water vapor removing unit.

  FIG. 7 is a perspective view (A) and a bottom view (B) showing another example of the duct. FIG. 7B shows a state where FIG. 7A is viewed in the positive Z-axis direction. FIG. 7 shows a duct 500. The duct 500 includes an enlarged portion 501 having a hollow structure, vertical portions 502a and 503a, extension portions 502b and 503b, and an extension portion connection portion 504, respectively.

  That is, the exhaust air from the suction fan 305 is expanded in the downstream direction in the expansion portion 501, and is guided to the vertical portions 502a and 503a that rise upward from both ends in the width direction of the downstream end of the expansion portion 501. Each of the upper portions of the vertical portions 502a and 503a is connected to extensions 502b and 503b extending in the upstream direction considered in the transport direction. The ends of the extension portions 502b and 503b are connected by an extension portion connection portion 504 extending in the width direction of the transport surface.

  A plurality of discharge ports 505 used as a transport surface discharge port in the present embodiment are formed on the lower surface (the surface side on which printing paper is transported) of the extension portion connection unit 504. The air flowing inside the duct 500 is exhausted downward (in the negative Z-axis direction) from the discharge port 505.

  In a state where the printing paper is conveyed below the discharge port 505, a force that is pressed against the conveyance surface by the air exhausted from the discharge port 505 acts on the printing paper. Further, the air exhausted from the discharge port 505 flows in a direction intersecting the printing paper conveyance direction (X-axis positive direction), and functions as an air curtain that prevents the outflow of the atmosphere from the heat fixing device in the downstream direction. To do.

  Discharge ports 506a and 506b used as downstream discharge ports in the present embodiment are formed in the wall surfaces of the vertical portions 502a and 503a on the transport surface side. A part of the air flowing in the duct 500 is exhausted from the discharge ports 506a and 506b. The exhaust flows in a direction intersecting the printing paper conveyance direction (X-axis positive direction) and functions as an air curtain that prevents the outflow of the atmosphere in the downstream direction.

(Modification)
Although an example in which a color image forming function is provided as the image forming unit 10 has been described, in the case of dedicated monochrome images, only one image forming unit is required. Further, the image forming unit may employ a configuration in which an image is temporarily transferred from a photosensitive drum to a transfer belt without being directly transferred from the photosensitive drum to a recording medium, and then transferred to a recording material.

  Moreover, you may arrange | position the heating means which heats the air in a duct. Examples of the heating means include an example of an electric heater that heats the duct or radiates heat in the duct. In this embodiment, a large number of holes (reference numerals 30 and 31 in FIG. 2 or FIG. 3) are formed in the conveyance belt in order to adsorb the recording material on the conveyance belt. The hole may be an elongated gap such as a slit. Further, it is also possible to divide the conveying belt into a plurality of parts and provide a gap in a portion adjacent to the conveying belt and suck the recording material to the conveying belt using this as a ventilation portion. Further, the number of the conveyor belt may be one, or three or more.

  In FIG. 1, the structure using the fixing belt 203 is illustrated as the heat fixing unit. However, the printing paper is directly sandwiched between the heat roll 201 and the pressure roll 202 without using the fixing belt 203. A configuration in which fixing is performed may be employed.

  The suction means may be an axial fan instead of the centrifugal fan structure. The cooling means may be configured such that the printing paper is sandwiched between a pair of rolls and cooling is performed by releasing heat to at least one of the rolls. The cooling means may be combined with a fan, a Peltier element, or a forced cooling means using water cooling.

  3 to 6, the duct 306 includes discharge ports that discharge air at both ends in the width direction of the surface on which the printing paper is transported. The intake fan 305 that sends air into the duct 306 includes a suction port 305a at an intermediate portion between both ends in the width direction of the surface on which the printing paper is conveyed. In this configuration, since the symmetry of the airflow from the discharge ports 307a and 307b to the suction port 305a is improved, the force for sucking the printing paper in the transport belts 302a and 302b is generated in a well-balanced manner.

  In the present embodiment, the conveyance belt 401 that contacts the printing paper is used as the cooling device. However, since a distance is provided between the heating fixing device and the cooling device, the heating fixing from the printing paper is performed as compared with the case where there is no distance. Since water vapor generated by heating in the apparatus reaches the cooling apparatus after being released into the air, the occurrence of condensation is suppressed.

  In the above embodiment, the operation when there is printing paper is described. However, even when there is no printing paper, for example, during the warm-up of the heat fixing device, suction is performed by the intake fan and the air passes through the duct. The air may be discharged to the conveying surface side. In general, when the heated printing paper is not in contact with the conveyance belt, the temperature of the conveyance belt is lower than that in contact, and the recording material is not in contact with the conveyance belt. The temperature difference is easy to occur. Here, when the intake and discharge are performed, the efficiency in which the conveyance belt is heated by the air heated by the warm-up of the heating and fixing device is increased as compared with the case where the intake and discharge are not performed. The temperature difference is difficult to occur. Further, in order to raise the temperature of air sucked by the intake fan to a high temperature, a configuration may be adopted in which heat escapes from the heat fixing device to the vicinity of the intake fan.

  The present invention can be used in an image forming apparatus.

1 is a conceptual diagram illustrating an example of an image forming apparatus using the invention. It is a perspective view which shows the outline | summary of a conveyance belt unit. It is a perspective view which shows a duct. It is a perspective view which shows the state which attached the conveyance belt unit to the duct. It is a perspective view which shows the other example of a duct. It is a perspective view which shows the other example of a duct. It is the perspective view (A) and bottom view (B) which show the other example of a duct.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Image forming part, 10Y ... Image forming unit, 10M ... Image forming unit, 10C ... Image forming unit, 10K ... Image forming unit, 11 ... Photoconductor drum, 12 ... Cleaning roll, 13 ... Exposure device, 14 ... Toner supply 15: transfer roll, 30 ... hole, 31 ... hole, 100 ... image forming apparatus, 101 ... recording material storage device, 102 ... printing paper, 103 ... transport path, 104 ... transport roller mechanism, 105 ... heat fixing device, DESCRIPTION OF SYMBOLS 106 ... Conveyance device, 107 ... Cooling device, 201 ... Heat roll, 202 ... Pressure roll, 203 ... Fixing belt, 204 ... Drive roll, 205 ... Belt cleaning roll, 300 ... Conveyance belt unit, 301 ... Housing, 302a ... Conveyance Belt, 302b ... Conveying belt, 303 ... Drive roll, 304 ... Guide roll, 305 ... Intake fan 305a ... intake port, 305b ... exhaust port, 306 ... duct, 307a ... discharge port, 307b ... discharge port, 308 ... discharge port, 309 ... casing, 401 ... transport belt, 402 ... transport belt, 403 ... heat sink, 404: Drive roll, 405: Tension roll, 406: Pressing roll group, 407: Drive roll, 408: Tension roll.

Claims (5)

A conveying unit that contacts a part of the recording material heat-fixed by the heating fixing unit and conveys the recording material;
In a section where the conveying means and the recording material are in contact, a suction means for sucking air on a surface side where the recording material comes into contact with the conveying means;
An air path portion constituting a path through which air sucked by the suction means flows;
A recording medium, comprising: a conveyance surface-side discharge port that is provided in the air path portion and that discharges air that has flowed through the air path portion to a conveyance surface side in contact with the recording material. Material transport device.   2. The recording material transport apparatus according to claim 1, wherein the transport surface side discharge port is a transport surface discharge port through which the transport unit discharges air toward a transport surface in contact with the recording material.   3. The recording according to claim 1, wherein the air path portion includes a downstream discharge port that discharges air in a direction intersecting with the conveyance direction of the recording material on the downstream side in the conveyance direction of the conveyance unit. Material transport device.   The recording material conveying apparatus according to claim 1, further comprising a water vapor removing unit that removes water vapor in the air path portion. Image forming means for forming an image on a recording material;
A heat fixing means for heat fixing the image formed by the image forming means to the recording material;
The recording material conveying device according to any one of claims 1 to 4,
Cooling means for cooling the recording material conveyed by the conveying means,
2. An image forming apparatus according to claim 1, wherein an image surface side of the recording material on which the image is heated and fixed by the heat fixing unit is not in contact between the heat fixing unit and the cooling unit.

Images