JP2014174497A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently dehumidify a conveyance roller, to reduce cost of an image forming apparatus.SOLUTION: A conveyance roller 29 includes a plurality of rotating roller members 29b attached to a rotating shaft 29a. The whole or a part of the rotating roller member 29b is arranged in an air supply area R formed by a pair of an air inlet 35a and an air outlet 30a. The air outlet 30a of an air intake duct 30 and the air inlet 35a of an exhaust duct 35 are arranged opposite to each other, and disposed for the rotating roller members 29b. The air supplied from the lower air outlet 30a to the upper air inlet 35a efficiently dehumidifies the conveyance roller 29 arranged in an intermediate position between the air outlet 30a and the air inlet 35a. The air supplied by an intake fan 31 from the air outlet 30a of the air intake duct 30 is supplied by an exhaust fan 36 to the air inlet 35a of the exhaust duct 35, and discharged to the outside of the device via the exhaust duct 35.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine thereof, and in particular, a fixing unit that heats an unfixed image and forms a fixed image on a transported recording medium is provided. The present invention relates to an image forming apparatus.

In an electrophotographic image forming apparatus, when a toner image on a recording material is heated and fixed, the paper is heated at a high temperature, so that water contained in the paper evaporates. When the heated water vapor is condensed on the transport roller on the downstream side in the recording medium transport direction of the fixing device and water droplets adhere thereto, an abnormal image may occur due to the transported paper picking up the water droplets. Therefore, a technique for exhausting air in the vicinity of the fixing device by providing an exhaust device (fan, duct, etc.) and dehumidifying the exhausted air by arranging a dehumidifying member in the exhaust path has already been considered. Are known.

In Patent Document 1 (Japanese Patent Laid-Open No. 2006-276215), for the purpose of preventing condensation on the conveyance roller and preventing the occurrence of abnormal images, an exhaust device is provided to exhaust the air in the vicinity of the fixing device, and in the exhaust path. An image forming apparatus that dehumidifies exhausted air by disposing a dehumidifying member is disclosed.

In the technique described in Patent Document 1, air in the image forming apparatus is dehumidified, and an exhaust device is provided so as not to cause an abnormality in image quality after image formation. This is a technology that increases the manufacturing cost of the device and the operating cost of the device, increases the size of the device, increases the energy consumption, and cannot detect the replacement timing of the exhaust device (fan, etc.).

However, in the image forming apparatus that exhausts the air of the fixing unit so far and dehumidifies the air exhausted into the apparatus, the cost of the dehumidifying member is high.If the dehumidifying member is eliminated, a larger exhaust device ( And the like, and the image forming apparatus is increased in size. In addition, there is a problem in that energy consumption increases with a large exhaust device. Furthermore, there is a problem that it is not possible to self-detect the replacement timing of the exhaust device (exhaust fan, etc.).

The present invention has been made in view of the above problems, and reduces the cost, reduces size, and saves energy of an image forming apparatus that exhausts air near the fixing device and dehumidifies the exhausted air. Another object of the present invention is to enable self-detection of the replacement timing of the exhaust device (fan or the like).

In order to achieve the above object, the present invention employs the following solutions. According to a first aspect of the present invention, there is provided a fixing unit that heats an unfixed image to form a fixed image on a recording medium, a conveyance roller roller having a rotating roller member attached to a rotating shaft, and recording after the fixed image is formed. A discharge unit that discharges the medium to the outside of the apparatus main body via a conveyance path including the conveyance roller roller, an intake fan that sucks air from the outside of the apparatus main body, and air that is sucked in by the intake fan is guided to the recording medium and the recording is performed. An air intake duct having a blower opening in the width direction of the medium and an inlet in the width direction of the recording medium, and an air inlet in the width direction of the recording medium. An image forming apparatus comprising: an exhaust duct that leads to exhaust; and an exhaust fan that exhausts the air that has flowed into the exhaust duct to the outside of the apparatus main body. Provided in a pair with respect to feed Rorakoro, it is characterized in that the portion of the rotating roller member blast area formed by the inlet and the blower opening or in whole, are arranged.

According to the present invention, the rotating roller member of the conveying roller roller is arranged so that all or part of the rotating roller member is included in the air blowing area formed by the inlet of the exhaust duct and the air outlet of the intake duct. With this arrangement, the air used for cooling the recording medium immediately after the fixing process is intensively guided to the rotating roller member of the conveying roller roller after the recording medium is cooled. As a result, the air can be efficiently exhausted to the outside by the exhaust duct having an inlet near the rotating roller member of the transport roller roller and the exhaust fan. Therefore, it is possible to efficiently dehumidify the rotating roller member of the transport roller roller without using a dehumidifying member and an exhaust fan that is large and expensive and consumes a large amount of energy.

In addition, by using a storage element (memory) that integrates the energization time of an exhaust fan or the like in the control unit of the image forming apparatus, the replacement time of an exhaust device (such as a fan) that has passed a predetermined energization time from the total energization time can be set. It can detect itself.

As described above, the cost of the image forming apparatus that exhausts the air in the vicinity of the fixing device and dehumidifies the exhausted air is reduced, the size is reduced, the energy is reduced, and the time for replacing the exhaust device (fan, etc.) It has an excellent effect of self-detecting.

1 is a schematic configuration diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram showing an intake / exhaust cooling system according to an embodiment of the present invention. It is the schematic which shows the Example of the conveyance roller roller which concerns on embodiment of this invention. It is the schematic which shows the positional relationship of the intake / exhaust cooling system which concerns on embodiment of this invention, and a conveyance roller roller.

An embodiment of the present invention will be described. The present invention has the following features when a method for preventing condensation on the transport roller roller and detecting the replacement timing of an intake fan, an exhaust fan, or the like.

In short, the rotating roller member of the conveying roller roller is arranged so that all or a part thereof is included in the air blowing area formed by the inlet port of the exhaust duct and the air blowing port of the intake duct. With this arrangement, the air used for cooling the recording medium immediately after the fixing process can be intensively guided to the conveyance roller roller section after the recording medium is cooled. Air can be efficiently exhausted outside the apparatus by an exhaust duct, an exhaust fan, or the like having an inlet near the rotating roller member of the transport roller roller. Therefore, it is characterized in that it is possible to efficiently dehumidify the rotating roller member of the transport roller roller without using a dehumidifying member or an exhaust fan fan that is large and expensive and consumes a large amount of energy.

In addition, by using a storage element (memory) that integrates the energization time of the exhaust fan or the like in the control unit of the image forming apparatus, the replacement timing of the exhaust fan or the like that has passed a predetermined energization time from the total energization time is self-detected. It is a feature.

The features of the present invention described above will be described in detail with reference to the following drawings. FIG. 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention. The configuration and operation of the entire image forming apparatus will be described with reference to FIG.

In the image forming apparatus 1 according to the present embodiment, a plurality of process cartridges 10Y, 10M, 10C, and 10BK are juxtaposed so as to face the intermediate transfer belt 17, and the recording medium P is moved upward from the lower sheet feeding unit 7. This is a tandem type color image forming apparatus that is conveyed in the vertical direction toward the paper feeding unit 5.

In FIG. 1, 1 is an image forming apparatus which is a main body of a color copying machine, 3 is a document conveying unit for conveying a document to a document reading unit 4, 4 is a document reading unit for reading image information of a document, and 6 is input image information. A writing unit (exposure unit) that emits laser light based on the above, 7 is a paper feeding unit that stores a recording medium P such as transfer paper, and 10Y, 10M, 10C, and 10BK are process cartridges (imaging units) corresponding to each color. , 17 is an intermediate transfer belt on which toner images of a plurality of colors are superimposed and transferred, 18 is a secondary transfer roller for transferring the toner image formed on the intermediate transfer belt 17 to the recording medium P, and 20 is on the recording medium P. A fixing unit for fixing an unfixed image, 28 is a toner container for supplying toner of each color to the developing devices of the process cartridges 10Y, 10M, 10C, and 10BK, and 30 is for cooling the recording medium P after the fixing process. Intake mechanism for (intake system), 35 is an exhaust duct (exhaust system) for discharging the warm air by the fixing unit 20 out of the apparatus. Here, the plurality of process cartridges 10Y, 10M, 10C, and 10BK are obtained by integrating the photosensitive drum 11 (image carrier), the charger, the developing unit, and the cleaning unit, respectively. Each process cartridge 10Y, 10M, 10C, 10BK is configured to be detachable from the image forming apparatus 1.

Hereinafter, an operation during normal color image formation in the image forming apparatus 1 will be described. First, the document is transported from the document table by the transport rollers of the document transport unit 3 and placed on the contact glass of the document reading 4. Then, the document reading unit 4 optically reads the image information of the document placed on the contact glass. The document reading unit 4 scans an image of the document on the contact glass while irradiating light emitted from an illumination lamp. Then, the light reflected from the original is imaged on the color sensor via the mirror group and the lens. The color image information of the document is read for each RGB color separation light by the color sensor and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by an image processing unit (not shown) based on RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information. . Image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 6. Laser light (exposure light) based on the image information of each color is irradiated (scanned) from the writing unit 6 onto the corresponding photosensitive drums 11 of the process cartridges 10Y, 10M, 10C, and 10BK.

On the other hand, the four photosensitive drums 11 rotate in the clockwise direction in the figure. The surface of the photosensitive drum 11 is uniformly charged at a position facing the charging unit (charging roller) (charging process). Thus, a charged potential is formed on the photosensitive drum 11. Thereafter, the surface of the charged photosensitive drum 11 reaches the irradiation position of each laser beam. In the writing unit 6, laser light corresponding to the image signal is emitted from the light source corresponding to each color.

The laser light is incident on the polygon mirror and reflected, and then passes through a plurality of lenses. The laser light after passing through a plurality of lenses passes through different optical paths for each of yellow, magenta, cyan, and black components (exposure process). Laser light corresponding to the yellow component is irradiated onto the surface of the photosensitive drum 11 of the first process cartridge 10Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 11 by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11 after being charged by the charging unit. Similarly, a magenta component electrostatic latent image, a cyan component electrostatic latent image, and a black component electrostatic latent image are formed on the corresponding photosensitive drum 11. Thereafter, the surface of the photosensitive drum 11 on which the electrostatic latent image of each color is formed reaches a position facing the developing unit. Each color toner is supplied onto the photosensitive drum 11 from each developing unit 13, and the electrostatic latent image on the photosensitive drum 11 is developed (developing step). Thereafter, the surface of the photosensitive drum 11 after the development process reaches a position facing the intermediate transfer belt 17 (intermediate transfer body). A primary transfer roller 14 is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 17. At the position of the primary transfer roller 14, the toner images of the respective colors formed on the photosensitive drum 11 are sequentially transferred onto the intermediate transfer belt 17 (first transfer process).

The surface of the photosensitive drum 11 after the first transfer process reaches a position facing the cleaning unit. The cleaning unit collects untransferred toner remaining on the photosensitive drum 11 (image carrier) (cleaning step). Thereafter, the surface of the photosensitive drum 11 passes through the position of the static eliminating unit, and a series of image forming processes on the photosensitive drum 11 is completed.

On the other hand, the surface of the intermediate transfer belt 17 on which the images of the respective colors on the photosensitive drum 11 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the secondary transfer roller 18. Then, the full color image on the intermediate transfer belt 17 is secondarily transferred onto the recording medium P at the position of the secondary transfer roller 18 (second transfer step). Thereafter, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning unit 9 (cleaning unit). Then, the untransferred toner on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit 9, and a series of transfer processes on the intermediate transfer belt 17 is completed.

Here, the recording medium P at the position of the secondary transfer roller 18 is transported from the paper feed unit 7 via a transport path K1 (paper feed transport path) in which a transport guide, a registration roller 19 and the like are installed. . The recording medium P fed by the paper feeding roller 8 from the paper feeding unit 7 that stores the recording medium P passes through the conveyance path K1, and is then guided to the registration roller 19. The recording medium P that has reached the registration roller 19 is conveyed toward the position of the secondary transfer roller 18 in synchronization with the toner image on the intermediate transfer belt 17.

Thereafter, the recording medium P on which the full-color image is transferred is guided to the fixing unit 20. In the fixing unit 20, a color image is fixed on the recording medium P at a fixing nip (not shown) (a nip where a fixing roller having a heater and a pressure roller are in pressure contact). The fixing unit 20 heats the unfixed image on the recording medium P conveyed to the fixing nip, and forms a fixed image on the recording medium P. Then, the recording medium P after the fixing process is stacked on the paper discharge unit 5 after being discharged as an output image from the main body of the image forming apparatus 1 by the transport roller roller 29 through the transport path K2 (discharge paper transport path). Thus, a series of image forming processes is completed. In the present embodiment shown in FIG. 1, the transport roller roller 29 is paired with a transport roller that is not indicated by a sign at an opposing position, and discharges the recording medium P to the paper discharge unit 5.

In FIG. 1, the transport roller roller 29 is driven by a drive mechanism (drive motor or drive gear train) (not shown) and forms a pair with a transport roller not indicated by a symbol. A configuration example of the transport roller roller 29 and the transport roller paired with the transport roller roller 29 will be described with reference to FIG.

The conveying roller roller 29 may be configured to discharge the recording medium P at a paper discharge nip formed by both of them as a guide structure for conveying a recording medium having a fixed structure (not shown) on the opposite side. Further, the roller facing the conveyance roller roller 29 may be a conveyance roller having a uniform roller structure. The conveyance roller roller 29 in the present invention refers to a structure in which a conveyance roller roller 29 is formed by attaching a rotary rotation roller member to a shaft that is rotationally driven as a roller. The rotational drive includes those in which the transport roller roller 29 itself has a drive mechanism or is passively driven by the rotational drive of another transport roller that forms a paper discharge nip. The conveyance roller roller 29 refers to one in which either one of the opposing members constituting the paper discharge nip includes a roller-shaped rotating roller member as a rotating member. Further, the conveyance roller roller 29 includes a roller roller that can be rotated by applying a biasing force to one of the rotation rollers of the conveyance roller pair that conveys the recording medium P in the conveyance path of the recording medium P. A roller roller roller that is provided in the conveyance path of the recording medium P and that forms a paper discharge nip and conveys the recording medium P is referred to as a conveyance roller roller.

  The transport roller roller 29 is made of a carbon steel material for mechanical structure as a rotating shaft 29a that is driven to rotate, and a roller-shaped rotating roller member 29b attached to the rotating shaft 29a is made of silicone rubber, fluorine rubber, or a foam thereof. Used.

Here, the image forming apparatus 1 in the present embodiment is configured to print on both sides of the recording medium P. During double-sided printing, the recording medium P after the fixing process on the front side is completed is conveyed to the position of the switchback roller 49, and after the conveyance direction is reversed, the recording medium P passes through the conveyance path K3 (double-sided conveyance path). Then, after passing through the second transfer process (transfer process to the back side surface) at the position of the secondary transfer roller 18 and the fixing process at the position of the fixing unit 20 again, it passes through the transport path K2 (discharge transport path). The paper is discharged to the paper discharge unit 5.

In the image forming apparatus 1 of FIG. 1 in the present embodiment, the recording medium P is formed so as to be able to print on both sides. However, the switchback roller 49, which is a mechanism unit for printing on both sides, It is also possible to simplify the configuration by omitting the double-sided conveyance path K3.

Further, the switchback roller 49 can have the same structure as the transport roller roller 29. A switchback conveyance nip of the recording medium P is formed as a pair with a conveyance roller (not indicated by a symbol) disposed opposite to the switchback roller 49.

In the image forming apparatus 1 according to the present embodiment, an intake duct that supplies cooling air (air) flowing from the outside of the image forming apparatus 1 toward a fixed image surface (surface on which a fixed image is formed) of the recording medium P is supplied. An intake / exhaust system including 30 (intake system) and an exhaust duct 35 (exhaust system) for discharging the cooling air (air) heated by the fixing unit 20 to the outside of the image forming apparatus 1 is installed. .

In addition, the intake / exhaust system of the image forming apparatus 1 according to the present embodiment includes a memory as a storage element in a control unit (not shown) that integrates energization time to the intake fan 31 and the exhaust fan 36 in the intake duct 30 and the exhaust duct 35. I have. The memory is provided in a control unit (not shown) and stores energization time (ventilation time) to the intake fan and exhaust fan measured by the control unit. When the control unit detects that a predetermined energization time (ventilation time) has passed, the control unit displays, for example, that it is time to replace the intake fan 31 or the exhaust fan 36 of the intake / exhaust system. It has. By displaying that the replacement time has been reached on a display device (not shown), the image forming apparatus 1 can perform self-detection and can easily perform necessary maintenance.

Further, the control unit may control the energization time and the air volume to the intake fan 31 and the exhaust fan 36 based on a sequence in a predetermined table. By individually controlling the energization cycle and the air volume control to the intake fan 31 and the exhaust fan 36, the intake fan 31 and the exhaust fan 36 are energized for a predetermined time at the start of image formation and at the end of image formation in addition to the time of image formation. Thus, the transport roller roller 29 can be dehumidified.

The configuration and operation of the intake duct 30 (intake system) and the exhaust duct 35 (exhaust system), which are characteristic in the present embodiment, will be described.

FIG. 2 is a diagram illustrating the configuration of the image forming apparatus that prevents condensation on the conveyance roller roller 29 and prevents the occurrence of abnormal images. FIG. 2 shows the fixing unit 20, the recording medium guide 29 G, the cooling air intake duct 30 in the recording medium cooling system, the intake fan (not shown), the blower opening 30 a provided in the intake duct 30, and the intake duct 30. A conveyance roller roller 29 that conveys the recording medium P is shown. Further, an exhaust duct 35 installed above the transport roller roller 29 and an exhaust fan 36 provided in the exhaust duct 35 are shown. 2, the conveyance roller roller 29 indicates the conveyance roller roller 29 in the single-side printing conveyance path of the recording medium P shown in FIG. 1, and the configuration relating to the conveyance roller roller 49 in the double-sided conveyance path K3 in FIG. 1 is omitted. In FIG. 2, the configuration in the case of single-sided printing of the recording medium P is shown as an embodiment.

A color image is fixed on the recording medium P at a fixing nip (not shown) of the fixing unit 20. The fixing unit 20 heats the unfixed image on the recording medium P conveyed to the fixing nip to form a fixed image on the recording medium P. The recording medium P after the fixing step is guided to the upper side of the fixing device 20 in FIG. 2 (downstream in the conveyance direction of the recording medium P). A series of image forming processes after being conveyed as an output image outside the image forming apparatus 1 main body by the conveying roller roller 29 through the conveying path K2 (discharged conveying path) shown in FIG. Is completed. In FIG. 2, a recording medium P (not shown) is guided to a conveyance roller roller 29 along a conveyance path K2 (not shown) (shown in FIG. 1), and is discharged out of the main body of the image forming apparatus 1 by the conveyance roller roller 29, as shown in FIG. Stacked on the paper discharge unit 5.

Cooling air (air) used for cooling the recording medium P immediately after the fixing process in the fixing unit 20 is guided by the intake fan 31 and the intake duct 30 for cooling the recording medium P, and the exhaust fan 36 and the exhaust duct 35 are further cooled. It is intensively guided to the conveying roller roller 29 by the exhaust action. Thereafter, air is exhausted outside the apparatus by the exhaust duct 35 and the exhaust fan 36 having an inlet near the conveyance roller roller 29, thereby efficiently using a dehumidifying member and an exhaust fan that is large and expensive and consumes a large amount of energy. Then, the transport roller roller 29 is dehumidified. By providing the blower opening 30a and the inflow port 35a at positions facing each other, a blower region can be formed.

  FIG. 3 is a diagram illustrating an example of the conveyance roller roller 29 according to the embodiment. FIG. 3A is a diagram illustrating Example 1 in which a conveyance nip N that conveys a recording medium P (not shown) is formed by a conveyance roller roller 29 and a conveyance guide 29G as a fixed member. The conveyance roller roller 29 includes a rotation shaft 292a and a rotation roller member 29b. FIG. 3B is a diagram illustrating Example 2 in which the transport nip N is formed by the transport roller roller 29 and the transport roller 29A. The entire transport roller 29A is configured in a roller shape with respect to the transport roller roller 29. FIG. 3C is a diagram illustrating a third embodiment in which the transport nip N is formed by the transport roller roller 29 and the transport roller roller 29B. The conveyance roller roller 29 </ b> B includes a rotation shaft 29 </ b> Ba and a rotation roller member 29 </ b> Bb, and forms a conveyance nip N between the rotation roller member 29 b of the conveyance roller roller 29.

By using the conveyance roller roller shape, the cooling air in the main body of the image forming apparatus 1 can be easily passed in the vicinity of the conveyance nip N formed by the rotating roller member 29b of the conveyance roller roller 29, and the efficiency of dehumidification with respect to the conveyance roller roller 29 is improved. The effect is to rise.

FIG. 4 shows the direction of the cooling air in the intake duct 30, the arrangement of the air outlet 30 a, the arrangement position of the inlet 35 a of the cooling air to the conveying roller roller 29, the rotating shaft 29 a and the rotating roller member 29 b, the exhaust duct 35, and the exhaust fan 36. FIG. FIG. 4A is a schematic diagram of the entire intake duct 35 (intake system) and exhaust duct 35 (exhaust system). FIG. 4B shows a blower port 30a of the intake duct 35, a rotary roller member 29b, an inlet 35a of the exhaust duct 35, a blower region R formed by the pair of blower ports 30a and the inlet 35a, and the blower region R. It is a figure which shows the installation position of the arrange | positioned rotation roller member 29b.

As shown in FIG. 4, a plurality of air outlets 30 a and inflow ports 35 a are provided in each duct in the width direction of the recording medium P, which is the longitudinal direction of the transport roller roller 29. Furthermore, by providing a plurality of rotary roller members 29b corresponding to the installation positions, it is possible to improve the efficiency of dehumidification by cooling air in the vicinity of the rotary roller member 29b.

In FIG. 4, a plurality of the air outlets 30 a and the inflow ports 35 a are provided, but only one set of the air outlet 30 a and the inflow ports 35 a may be formed. A plurality of inflow ports 35a may be provided corresponding to one air blowing port 30a. One inflow port 35a may be provided corresponding to the plurality of air blowing ports 30a. What is necessary is just to install so that the rotation roller member 29b of the conveyance roller roller 29 may be located in the ventilation area | region R which both inflow ports 35a form with respect to the ventilation port 30a. Thus, even when one air blowing region R is formed by a combination of one or a plurality of the air outlets and one or a plurality of the inlets, the rotating roller member 29b of the transport roller roller 29 is provided in the air blowing region R. It only needs to be installed so as to be located. The efficiency of dehumidification by the cooling air in the vicinity of the rotary roller member 29b can be improved.

As shown in FIG. 4B, the transport roller roller 29 having a plurality of rotating roller members 29b attached to the rotating shaft 29a has a pair of flow rollers 29b as a whole or a part of the rotating roller member 29b. It exists in the position contained in the ventilation area | region R which the entrance 35a and the ventilation port 30a form. In the present embodiment, the air blowing port 30a of the intake duct 30 and the inflow port 35a of the exhaust duct 35 are provided at opposing positions, and a plurality of them are provided corresponding to the plurality of rotating roller members 29b. By conveying air from the lower air inlet to the upper air inlet, the transport roller roller 29 disposed at a position intermediate between the air outlet and the air inlet is efficiently dehumidified as a whole roller roller. Cooling air from the blower opening 30a of the intake duct 30 is ventilated by the intake fan 31 to the inlet 35a of the exhaust duct 35 by the exhaust fan 36, and further exhausted to the outside of the image forming apparatus 1 through the exhaust duct 35. The rotating roller member 29b and the transport roller roller 29 are dehumidified.

When the opening size (opening area) of the air blowing port 30a of the intake duct 30 is made smaller than the opening size (opening area) of the inflow port 35a of the exhaust duct 35, the air is sucked by the intake fan 31 and rises. The effect of improving the efficiency of taking the cooled air into the exhaust duct 35 is produced. Further, the cooling air taken into the exhaust duct 35 is discharged to the outside of the image forming apparatus 1 by the exhaust fan 36, whereby the transport roller roller 29 can be effectively dehumidified. Further, by making the total opening size (opening area) of the air blowing port 30 a in the intake duct 30 smaller than the total opening size (opening area) of the inflow port 35 a of the exhaust duct 35, the intake air is sucked by the intake fan 31. As a result, the efficiency of taking the raised cooling air into the exhaust duct 35 is improved.

By making the width 35b of the inlet 35a of the exhaust duct 35 larger than the width 29c of the rotary roller member 29b, the cooling air that is sucked by the intake fan 31 and rises from the air outlet 30a of the intake duct 30 is exhausted. When the air is taken into the inflow port 35a, the rotary roller member 29b can be ventilated so as to be in contact with the whole or a part thereof. Further, by discharging the cooling air to the outside of the image forming apparatus 1, the transport roller roller 29 and the rotating roller member 29b can be dehumidified effectively. Even when a plurality of inflow ports 35a are arranged in one air blowing region R, the width 35b of one inflow port 35a is made larger than the width 29c of the rotating roller member 29b, so that the conveying roller roller 29 and the rotating roller member 29b Dehumidification can be performed effectively.

Further, by making the air volume of the exhaust fan 36 larger than the air volume of the intake fan 30, the cooling air can be surely ventilated from the air blowing port 30a to the inflow port 35a, and the dehumidification of the conveying roller roller 29 and the effect is effective. Can be done automatically.

In the paper discharge nip N formed between the members facing the conveying roller rollers 29, the conveying roller rollers 29 form a gap that allows ventilation between the members in contact with the rotating roller members 29b. As a result, the transport roller roller 29 is efficiently dehumidified.

A switchback roller 49 shown in FIG. 1 having the same configuration as that of the conveying roller cam 29 is installed in the intake / exhaust system described above, as shown in FIG. Moisture generated in the fixing unit 20 is discharged to the outside of the image forming apparatus 1 by the intake / exhaust system according to the present invention, and the switchback roller 49 and a rotary roller member (not shown) can be dehumidified.

In this image forming apparatus, the transport roller roller is efficiently dehumidified, thereby exhausting the air in the vicinity of the fixing portion of the image forming apparatus and obtaining a high-quality image free from the influence of humidity. In addition, the cost of the image forming apparatus for dehumidifying the exhausted air can be reduced, the size and energy can be reduced, and the replacement timing of the exhaust fan can be detected by itself.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus intermediate transfer belt 3 Original conveyance part 4 Original reading part 5 Paper discharge part 6 Writing part 7 Paper feed part 8 Paper feed roller 9 Intermediate transfer belt cleaning part 10Y, 10M, 10C, 10BK Process cartridge 11 Photosensitive drum 14 Primary transfer roller 17 Intermediate transfer belt 18 Secondary transfer roller 19 Registration roller 20 Fixing unit 28 Toner container 29 Conveying roller roller 29a Rotating shaft 29b Rotating roller member 29c Rotating roller member width 29G Recording medium conveying guide 29A Conveying roller 29B Conveying roller roller 29Ba Rotating Shaft 29Bb Rotating roller member 30 Intake duct 30a Blower 31 Intake fan 35 Exhaust duct 35a Inlet 35b Inlet width 36 Exhaust fan 49 Switchback roller K1 Conveyance path K2 Conveyance path K3 Conveyance path P Recording medium R Blower area N Conveying nip

JP 2006-276215 A

Claims (10)

A fixing unit for heating an unfixed image to form a fixed image on a recording medium, a conveying roller roller having a rotating roller member attached to a rotation shaft, and a conveying path including the conveying roller roller for fixing the recording medium for forming a fixed image. A discharge unit that discharges the air to the outside of the apparatus main body, an intake fan that sucks air from the outside of the apparatus main body, and air that is sucked in by the intake fan to the recording medium, and an air intake that has a blower port in the width direction of the recording medium A duct, an exhaust duct installed in the width direction of the recording medium, having an inlet in the width direction of the recording medium, and guiding the air flowing in from the inlet to the outside of the apparatus main body, and the exhaust In an image forming apparatus comprising: an exhaust fan that exhausts air flowing into a duct to the outside of the apparatus body;
The air blowing port and the inflow port are provided as a pair with respect to the conveying roller roller, and a part of the rotating roller member or the entire rotating roller member is disposed in the air blowing region formed by the air blowing port and the inflow port. An image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the air blowing area is formed by a combination of one or a plurality of the air outlets and one or a plurality of the inflow ports. 3. 3. The image forming apparatus according to claim 1, wherein a plurality of the blowing regions are provided, and a part of the rotating roller member or the entire rotating roller member is disposed in the blowing region with respect to one blowing region. An image forming apparatus. 4. The image forming apparatus according to claim 1, wherein a width of the inlet is larger than a width of the rotating roller member. 5.   5. The image forming apparatus according to claim 1, wherein an opening area of the inflow port is larger than an opening area of the air blowing port. 6. 6. The image forming apparatus according to claim 1, wherein an air volume of air from the exhaust fan is configured to be larger than an air volume of air from the intake fan, and is greater than an air volume of air from the intake duct. And an image forming apparatus characterized in that the air volume from the exhaust duct is increased. 7. The image forming apparatus according to claim 1, further comprising a control unit having a storage element that integrates energization time of the intake fan and the exhaust fan. 8. The image forming apparatus according to claim 7, further comprising a display unit that displays that the energization time accumulated in the storage element has reached a predetermined time. 9. The image forming apparatus according to claim 1, further comprising a double-sided conveyance path for conveying the image to form an image on the remaining one side after fixing to the recording medium on the conveyance path. An image forming apparatus. 10. The image forming apparatus according to claim 9, wherein a conveying roller roller having a rotating roller member attached to a rotating shaft is disposed in the recording medium discharge portion of the double-sided conveying path.

Images