Patent ID: 12248258

DESCRIPTION OF THE EMBODIMENTS

First Exemplary Embodiment

A first exemplary embodiment of the present disclosure will be described in detail with reference toFIGS.1through5B. A tandem-type full-color printer will be described as one example of an image forming apparatus1. However, the present disclosure is not limited to be the tandem-type image forming apparatus1and may be another type image forming apparatus. Still further, the present disclosure is not limited to be the full-color image forming apparatus and may be a monochromatic or a mono-color image forming apparatus.

Image Forming Apparatus

As illustrated inFIG.1, the image forming apparatus1is an electro-photographic full-color printer including image forming units PY, PM. PC and PK of four colors of yellow (Y), magenta (M), cyan (C) and black (K) within an apparatus body1aof the image forming apparatus1. The present exemplary embodiment adopts an intermediate transfer tandem system in which the image forming units PY, PM, PC and PK are arrayed along a rotation direction of an intermediate transfer belt7described later. The image forming apparatus1forms a toner image, i.e., an image, onto a recording material S corresponding to an image signal transmitted from a host device such as a document reading apparatus not illustrated and connected to the apparatus body1aand a personal computer communicably connected to the apparatus body1a. The recording material S is a sheet member such as a sheet of paper, a plastic film and a cloth. The image forming apparatus1also includes a control portion20for executing various controls of an image forming process and others.

The image forming process of the image forming units will be described. Firstly, the image forming units PY PM, PC and PK will be described. In the present exemplary embodiment, because the image forming units PY, PM, PC and PK are constructed approximately in the same manner except that colors of toners are different, the following description will be made by typically exemplifying the yellow image forming unit PY and by omitting descriptions of the other image forming units PM, PC and PK.

The image forming unit PY includes a photosensitive drum2, a charging unit3, an exposing unit4and a developing unit5. A surface of the photosensitive drum2serving as one example of a rotationally driven image bearing member is homogeneously charged in advance by the charging unit3, and then, an electrostatic latent image is formed on the surface of the photosensitive drum2by the exposing unit4driven based on image information signals. That is, the electrostatic latent image is formed on the photosensitive drum2. The electrostatic latent image thus formed on the photosensitive drum2is developed by the developing unit5by toner and is visualized as a toner image. An amount of the toner within the developer consumed in the image forming process is replenished from a toner cartridge not illustrated together with carrier.

After that, a predetermined pressure and a primary transfer bias are applied to the toner image formed on the photosensitive drum2by a primary transfer roller6disposed so as to face the photosensitive drum2across the intermediate transfer belt7to primarily transfer the toner image to the intermediate transfer belt7. Residual toner slightly left on the photosensitive drum2after the primary transfer is removed by a cleaning unit8to be ready for a next image forming process.

The intermediate transfer belt7is stretched by a tension roller10, a secondary transfer inner roller11and a driving roller12and is driven by the driving roller12such that the intermediate transfer belt7moves in a rotation direction R1. The image forming processes of the respective colors performed by the image forming units PY, PM, PC and PK are carried out with timing of sequentially overlapping on each color toner image primarily transferred on the intermediate transfer belt7upstream in the moving direction. As a result, finally a full-color toner image is formed on the intermediate transfer belt7and is conveyed to a secondary transfer portion15. The secondary transfer portion15is a transfer nip portion formed by a part of the intermediate transfer belt7stretched by the secondary transfer inner roller11and a secondary transfer outer roller13. It is noted that transfer residual toner after passing through the secondary transfer portion15is removed out of the intermediate transfer belt7by a transfer cleaning unit14.

A conveyance process of the recording material S to the secondary transfer portion15is synchronously executed with the forming process of the toner image sent to the secondary transfer portion15. In the conveyance process, the recording material S is fed from a sheet cassette or the like not illustrated and is sent to the secondary transfer portion15synchronously with the image forming timing. A secondary transfer voltage is applied to the secondary transfer inner roller11at the secondary transfer portion15.

The toner image is thus secondarily transferred from the intermediate transfer belt7onto the recording material S at the secondary transfer portion15by the image forming process and the conveyance process. That is, the image forming unit forms the toner image onto the photosensitive drum2and the toner image born on the photosensitive drum2is transferred onto the recording material S. After that, the recording material S is conveyed to a fixing unit30to be heated and pressurized by the fixing unit30such that the toner image is melt and fixed onto the recording material S. That is, the fixing unit30fixes the unfixed toner image that has been formed by the image forming unit onto the recording material S. The recording material S onto which the toner image has been thus fixed is discharged by a discharge roller onto a discharge tray not illustrated.

Control Portion

The image forming apparatus1includes a control portion20for executing various controls such as the image forming process described above. That is, the control portion20provided in the image forming apparatus1controls operations of the respective portions thereof. The control portion20controls the series of image forming operations in accordance with an operating portion provided on an upper surface of the apparatus body1aor with each input signal transmitted through a network.

As illustrated inFIG.2, the control portion20includes a Central Processing Unit (CPU)21serving as an arithmetic operation unit, a Read Only Memory (ROM)22, a Random Access Memory (RAM)23and others. The CPU21controls the respective portions of the image forming apparatus1while reading out a program corresponding to a control procedure stored in the ROM22. The RAM23stores operational data and input data, and the CPU21controls by making reference to the data stored in the RAM23based on the abovementioned program. The control portion20is connected with a suction fan16described later, a driving motor MI for driving a fixing belt41and others and is capable of controlling the fixing unit30.

Fixing Unit

Next, the fixing unit30will be described in detail with reference toFIG.3. As illustrated inFIG.3, the fixing unit30is constructed in a manner of a cartridge attachable to/detachable from the apparatus body1aof the image forming apparatus1(seeFIG.1). The fixing unit30includes a casing31, a heating portion40, a pressure roller32which is one example of a second rotary member, a discharge side guide portion50and an air duct60. As illustrated inFIG.8, the fixing unit30is supported by a drawing portion100that can be drawn out of the apparatus body1aof the image forming apparatus1.

The heating portion40includes a fixing belt41which is one example of a first rotary member endlessly rotatable in a rotation direction R2, a pressure pad42which is a nip forming member, a heating roller43, a steering roller44and a stay45. The respective components described above of the heating portion40are integrated into a cartridge by unit side plates not illustrated and the heating portion40is detachably attached to the casing31.

The fixing belt41is a thin and cylindrical belt member having thermal conductivity, heat resistance and others and configured to come into contact with the recording material S to heat the recording material S. According to the present exemplary embodiment, the fixing belt41has a three layer structure of a base layer, an elastic layer laid around the base layer and a releasing layer laid around the elastic layer. The base layer is 60 μm thick and is formed of polyimide resin (PI). The elastic layer is 300 μm thick and is formed of silicon rubber. The releasing layer is 30 μm thick and is formed of PFA (tetrafluoroethylene-perfluoroalkoxylene copolymer resin). The fixing belt41is stretched by the pressure pad42, the heating roller43which is one example of a stretch roller and the steering roller44. According to the present exemplary embodiment, an outer diameter of the fixing belt41is 120 mm for example and a rotational speed thereof is 300 mm's for example.

The pressure pad42is supported by the stay45and is pressed to the pressure roller32across the fixing belt41. The stay45is formed of stainless steel, and both end portions in a sub-scan direction of the stay45are supported by the casing31of the fixing unit30. It is noted that the sub-scan direction is a direction orthogonal to a conveyance direction of the recording material S that has passed through a fixing nip portion N and is a rotation axial direction of the fixing belt41for example. The fixing nip portion N which is one example of a nip portion is formed by contact portion of the fixing belt41and the pressure roller32. That is, the pressure pad42is disposed so as to face the pressure roller32across the fixing belt41and forms the fixing nip portion N between the fixing belt41and the pressure roller32.

The pressure pad42is made from LCP (liquid crystal polymer) resin for example. A lubricating sheet not illustrated is interposed between the pressure pad42and the fixing belt41. The lubricating sheet is made from a PI (polyimide) sheet coated by PTFE (polytetrafluoroethylene) of 100 μm thick for example. Projections of 100 μm are formed on the PI sheet at intervals of 1 mm to reduce sliding resistance by reducing a contact area with the fixing belt41. Lubricant is applied to an inner surface of the fixing belt41such that the fixing belt41slides smoothly against the pressure pad42.

Lubricant not illustrated is applied in advance to the lubricating sheet on a side of a contact surface with the fixing belt41to improve slidability. Oil is used as the lubricant in the present exemplary embodiment. While silicon oil is preferably used as the oil from an aspect of heat resistance and others and while oils of various viscosities are used, normally oil of 30,000 cSt or less is used because fluidity during application is inferior if the viscosity is too high. Specifically, while dimethyl silicon oil, amino-modified silicon oil, fluorine-modified silicon oil or the like is used as the oil, the oil of the present disclosure is not specifically limited to them.

The heating roller43is a stainless steel pipe of 1 mm thick and includes a heater not illustrated and composed of a halogen heater for example. The heating roller43can be heated up to a predetermined temperature, e.g., 180° C. The fixing belt41is heated by the heating roller43and is controlled up to a predetermined target temperature corresponding to a type of a sheet based on temperature detected by a thermistor not illustrated. Still further, a gear not illustrated is fixed to one end portion in a rotation axial direction of the heating roller43to connect with the driving motor MI (seeFIG.2) through the gear to be rotationally driven. The fixing belt41is rotated following the rotation of the heating roller43. Although a case where the heater can heat the fixing belt41is described in the present exemplary embodiment, the present disclosure is not limited to such configuration and the heater may heat at least one of the fixing belt41and the pressure roller32.

The steering roller44has a pivot axis in an approximately vertical direction at one end portion or near a center part in a rotation axial direction thereof and pivots with respect to the fixing belt41to generate a difference in tension in a main scanning direction and to adjust a position in the main scanning direction of the fixing belt41. It is noted that the steering roller44is a tension roller urged by an urging spring not illustrated and supported by a frame of the heating portion40to apply a predetermined tension to the fixing belt41.

The pressure roller32faces the fixing belt41to contact with each other and forms the fixing nip portion N pressed between the pressure roller32and the fixing belt41. The pressure roller32is a roller which includes an elastic layer formed around a shaft of the pressure roller32and a releasing layer formed around the elastic layer. The shaft of the pressure roller32is made from stainless steel, and conductive silicon rubber of 5 mm thick is used as the elastic layer. The releasing layer is 50 μm thick and is formed of PFA (tetrafluoroethylene-perfluoroalkoxylene copolymer resin) as fluororesin. The pressure roller32is axially supported by the casing31of the fixing unit30. A gear not illustrated is fixed at one end portion in the rotation axial direction of the pressure roller32to be connected with the dnving motor MI (seeFIG.2) through the gear to be rotationally driven.

The toner image on the recording material S is heated while being nipping and conveyed at the fixing nip portion N formed between the fixing belt41and the pressure roller32as illustrated inFIG.1. Thus, the fixing unit30fixes the toner image onto the recording material S while nipping and conveying the recording material S. Accordingly, the fixing unit30is required to achieve the both functions of applying heat and pressure and of conveying the recording material S.

The pressure roller32is pressed by a pressure spring not illustrated through a pressure frame not illustrated. Because the pressure frame moves to a side of the heating portion40after fixing the stay45to the casing31, the pressure roller32is pressed to the pressure pad42through the fixing belt41. A pressurizing force of the pressure roller32applied to the pressure pad42during the image forming process is set at 1,000 N for example. Still further, a separating member46configured to separate the recording material S that has passed through the fixing nip portion N from the fixing belt41is swingably supported by the casing31. While the separating member46is a rectangular plate-like member along the rotation axial direction, one or a plurality of contact type separation claws may be disposed depending on conditions of adhesive strength between the recording material S and the fixing belt41and of the toner image.

The casing31includes a main body33and a cover34provided above the main body33to be openable/closable and stores the heating portion40and the pressure roller32. The casing31also includes a carry-n port36for carrying in the recording material S and a sheet discharge port37for discharging the recording material S that has passed through the fixing nip portion N. The sheet discharge port37is provided at aside portion31adownstream in the conveyance direction of the casing31. A sheet conveyance path38which is a straight conveyance path for carrying in and discharging the recording material S bearing the toner image to be heated and fixed is formed from the carry-in port36to the sheet discharge port37. According to the present exemplary embodiment, the sheet conveyance path38is provided horizontally.

The casing31also includes an opening portion31bthat permits to access to the sheet conveyance path38downstream in the conveyance direction from the fixing nip portion N at the side portion31aand a door35serving as one example of an opening and closing member capable of opening/closing the opening portion31b. The door35is provided to be able to open/close the casing31to facilitate a jam treatment. The sheet discharge port37is provided through the door35according to the present exemplary embodiment.

A carry-in side guide portion39is provided along the sheet conveyance path38between the carry-in port36and the fixing nip portion N. A discharge side guide portion50is also provided along the sheet conveyance path38between the fixing nip portion N and the sheet discharge port37. The discharge side guide portion50includes an upper guide51which is one example of a first guide portion provided on an upper side of the sheet conveyance path38and a lower guide52which is one example of a second guide portion provided on a lower side of the sheet conveyance path38. The upper and lower guide portions51and52are disposed so as to face with each other across the sheet conveyance path38. The recording material S which has heated and fixed at the fixing nip portion N passes between the upper and lower guides51and52and is discharge out of the fixing unit30from the sheet discharge port37.

Discharge Side Guide Portion

Next, a configuration of the discharge side guide portion50will be detailed with reference toFIG.4. Here, a width direction W inFIG.4indicates the sub-scanning direction, e.g., the rotation axial direction of the fixing belt41. The upper and lower guides51and52are provided with the vent holes53and54, respectively, such that air between the upper and lower guides51and52readily passes upward. The vent holes53and54penetrate in a direction intersecting with the sheet conveyance path38, i.e., in a vertical direction in the present exemplary embodiment.

The vent holes53and54are provided due to the following reason. The air in a space between the upper and lower guides51and52contains a lot of moisture because the moisture contained in the recording material S is evaporated as the recording material S is nipped and heated at the fixing nip portion N between the fixing belt41and the pressure roller32. Therefore, if this air is kept within the fixing unit30, the moisture soon reaches to an amount of saturated water vapor and is condensed into dew, possibility causing various troubles such as image defects and conveyance failures. Then, the vent holes53and54are provided through the upper and lower guides51and52such that the air between the upper and lower guides51and52can be readily emitted out of the space between the upper and lower guides51and52. This arrangement makes it possible to suppress the vapor generated in the process of heating and fixing the toner image from leaking out and condensing into dew within the fixing unit30or within post-processing apparatus located downstream in the sheet conveyance direction of the fixing unit30.

It is noted that while the vent holes53and54are provided through the upper and lower guides51and52such that the move of the air is facilitated in the present exemplary embodiment, the present disclosure is not limited to such configuration and the move of the air may be facilitated by providing vent holes at least through one of the upper and lower guides51and52. Still further, while the vent holes53and54are provided through the upper and lower guides51and52in the present exemplary embodiment, the present disclosure is not limited to the shape of holes as long as the move of the air is facilitated. For instance, ribs higher than normal ribs may be provided on sheet passing surfaces of the upper and lower guides51and52to suppress the air from being retained. Or, even if the moisture is condensed into dew, it is possible to suppress the dew condensed moisture from adhering to the recording material S by keeping the dew condensation away vertically from the recording material S.

Air Duct

Next, a configuration of an air duct60serving as one example of a first duct will be detailed with reference toFIGS.5A and5B. The air duct60is provided downstream of the fixing nip portion N in the conveyance direction of the recording material S within the casing31to suction the air containing the vapor of the recording material S generated when the recording material S is heated at the fixing nip portion N. The air duct60is linked with a suction fan16which is one example of a suction unit provided in the apparatus body1aof the image forming apparatus1(seeFIG.1) to suction the air downstream in the conveyance direction of the fixing nip portion N of the casing31. It is noted that the suction fan16may be a fan dedicated for the air duct60or may be a fan used also for another use. It is also noted that a main body air duct including the suction fan and provided in the apparatus body1aof the image forming apparatus1is configured to be connected with the air duct60when the door35is closed and to be disconnected from the air duct60when the door35is opened.

The air duct60is provided on the door35and is disposed above the sheet discharge port37. The air duct60includes a suction port61opened downward and a communicating port62serving as one example of an exhaust port provided on a rear side W1of the width direction W, i.e., on a back surface side of the apparatus body1a. As illustrated inFIG.3, the suction port61is formed so as to face the discharge side guide portion50. As illustrated also inFIGS.5A and5B, the communicating port62is linked with the suction fan16. The air duct60is provided such that a longitudinal direction thereof extends in the width direction W such that the air containing the vapor generated from the recording material S can be suctioned across an entire range of the longitudinal direction.

In the present exemplary embodiment, the image forming apparatus1includes a connecting duct66, serving as one example of a second duct, configured to connect with the communicating port62of the air duct60to exhaust air out of the image forming apparatus1. The connecting duct66is separated from the air duct60in a state in which the door35opens the sheet conveyance path38. The connecting duct66is connected with the air duct60in a state in which the door35closes the sheet conveyance path38. The air duct60is provided to be movable in the apparatus body1aand the connecting duct66is provided to be fixed in the apparatus body1a. The suction fan16is provided in the connecting duct66.

According to the present exemplary embodiment, the air duct60is disposed on the side of the fixing belt41, i.e., on the side of the first rotary member or on an upper side, with respect to the sheet conveyance path38downstream in the conveyance direction of the fixing nip portion N. Because the air duct60is disposed above the sheet conveyance path38, the air duct60can efficiently suction the hot air containing the vapor generated in the vicinity of the upper and lower guides51and52when the hot air rises. However, the position where the air duct60is disposed is not limited to the upper side of the sheet conveyance path38and may be disposed under the sheet conveyance path38. It is possible to suction the air containing the vapor generated in the vicinity of the upper and lower guides51and52also in this case. The position where the air duct60is disposed may be the both sides above and under the sheet conveyance path38.

The air duct60is formed of the door35of the casing31and a duct member63attached to the door35. The duct member63is formed approximately into a plate-like member such that a width direction W thereof is the longitudinal direction. The duct member63is attached to an inner side surface of the door35. Thus, the tubular air duct60is formed by the inner side surface of the door35, the ribs64formed on the inner side surface of the door35and the duct member63. The plurality of ribs64is provided from the suction port61to the communicating port62and functions as straightening ribs that rectifies the air suctioned to the air duct60from the suction port61to the communicating port62. It is possible to suction the air uniformly across the whole range in the width direction W. i.e., in the longitudinal direction, by providing the ribs64as described above. While the plurality of ribs64which is one example of the straightening rib is provided on the door35in the present exemplary embodiment, the present disclosure is not limited to such arrangement and the ribs may be provided at least one of the door35and the duct member63.

As described above, the fixing unit30of the present exemplary embodiment includes the air duct60provided downstream in the conveyance direction of the recording material S of the fixing nip portion N in the casing31. Therefore, it is possible to suppress the image forming apparatus1from being enlarged as compared to a case where the air duct60is provided at a place separated from the fixing unit30. That is, if the air duct60is provided at a place separated from the fixing unit30in the image forming apparatus1, it is required to provide a clearance between the fixing unit30and the air duct60, possibly enlarging the image forming apparatus1. However, because such clearance is unnecessary in the fixing unit30of the present exemplary embodiment, the image forming apparatus1can be downsized. Still further, because the air duct60is provided on the door35, it is possible to save a space in terms of a layout within the fixing unit30as compared to a case where the air duct60is provided at another region.

In a case where the air duct60is provided at a place separated from the fixing unit30in the image forming apparatus1, it becomes hard to remove the vapor generated from the recording material S right after passing through the fixing nip portion N. However, because the air duct60is provided in the casing31in the fixing unit30of the present exemplary embodiment, it is possible to efficiently remove the vapor generated from the recording material S right after passing through the fixing nip portion N. Still more, because the air duct60is provided separately from the fixing nip portion N, it is possible to suppress heat necessary for fixing the recording material S at the fixing nip portion N from being lost.

Still further, the vent holes53and54are provided through the upper and lower guides51and52in the fixing unit30of the present exemplary embodiment. This arrangement makes it possible to readily suction the air containing the vapor accumulated between the upper and lower guides51and52upward by the air duct60. Therefore, because the vapor generated in the heating and fixing process does not leak out of the sheet discharge port37, is not accumulated between the upper and lower guides51and52and can be efficiently suctioned by the air duct60, it is possible to suppress the dew condensation from being otherwise generated within the fixing unit30.

It is noted that while the case where the air duct60is formed by the door35and the duct member63has been described in the fixing unit30of the present exemplary embodiment described above, the present disclosure is not limited to such configuration. For instance, a tubular air duct may be attached to the door35. Still further, the case where the plurality of ribs64serving as the straightening rib is provided within the air duct60has been described in the fixing unit30of the present exemplary embodiment, the present disclosure is not limited to such configuration. The rib64may be one or may be eliminated.

Still further, the case where the air duct60is formed inside of the casing31has been described in the fixing unit30of the present exemplary embodiment described above, the present disclosure is not limited to such configuration. For instance, it is possible to obtain the air duct integrated with the casing31by attaching a duct member on an outer side surface of the casing31or by attaching a tubular air duct on an outer surface of the casing31. In this case, the suction port of the air duct is configured to penetrate through the casing31and to face the sheet conveyance path38within the casing31. It is possible to suppress the image forming apparatus1from being enlarged as compared to the case where the air duct60is provided at a place separated from the fixing unit30.

Still further, while the sheet conveyance path38is formed horizontally in the fixing unit30of the present exemplary embodiment described above, the present disclosure is not limited to such configuration and the sheet conveyance path38may be formed vertically. In this case, the same effect with what described above may be obtained by providing the air duct60on a side of the horizontal direction of the discharge side guide portion50.

Still further, while the case where the first rotary member is the fixing belt41and the second rotary member is the pressure roller32has been described in the fixing unit30of the present exemplary embodiment described above, the present disclosure is not limited to such configuration. For instance, the first rotary member may be a fixing roller and the second rotary member may be a pressure belt.

Second Exemplary Embodiment

Next, a second exemplary embodiment of the present disclosure will be detailed with reference toFIG.6. A configuration of the present exemplary embodiment is different from that of the first exemplary embodiment in that a casing131of a fixing unit130includes a main body133and a cover134and includes no door. The configuration of the second exemplary embodiment is the same with that of the first exemplary embodiment other than that, components of the second exemplary embodiment will be denoted by the same reference signs and their detailed description will be omitted here.

According to the present exemplary embodiment, the cover134covers the sheet conveyance path38and forms the carry-in port36and the sheet discharge port37between the main body133. The sheet discharge port37is provided on a side131adownstream in the conveyance direction of the casing131. The air duct60is provided on a side wall135of the side portion131aof the casing131and is disposed above the sheet discharge port37. The air duct60is composed of the side wall135of the casing131and the duct member63attached to the side wall135. The other configuration of the air duct60is the same with that of the first exemplary embodiment.

It is possible to suppress the image forming apparatus1from being enlarged also by the fixing unit130of the present exemplary embodiment as compared to a case where the air duct60is provided at a place separated from the fixing unit130as well as the first exemplary embodiment. Still further, because the air duct60is provided on the side wall135, it is possible to save a space in terms of a layout within the fixing unit130as compared to a case where the air duct60is provided at another region.

Third Exemplary Embodiment

Next, a third exemplary embodiment of the present disclosure will be described in detail with reference toFIG.7A. In the present exemplary embodiment, a post-processing apparatus9is connected to the image forming apparatus1to which the fixing unit30of the first exemplary embodiment is applied. Because the configuration of the fixing unit30is the same with that of the first exemplary embodiment, the components are denoted by the same reference signs and their detailed description will be omitted here. Note that a sheet discharging apparatus such as a sorter, a cooling unit and others are widely applicable as the post-processing apparatus9.

Here, a case where a fixing unit230of the image forming apparatus101has no air duct60as illustrated by a comparative example inFIG.7Bwill be described. In this case, the vapor of the recording material S is liable to condensed to dew on a discharge side guide portion50downstream in the conveyance direction of the fixing nip portion N (seeFIG.3) and on guide plates191and192of the post-processing apparatus109. Although an air duct160may be provided upstream of the guide plates191and192in the post-processing apparatus109in order to solve this problem, it is unable to suppress dew condensation at the discharge side guide portion50of the fixing unit230. In the same manner, it is unable to suppress dew condensation on the discharge side guide portion50of the fixing unit230even if an air duct is provided between the fixing unit230and a sheet discharge port of the image forming apparatus101.

Then, it becomes unnecessary to provide an air duct in the post-processing apparatus9because the air duct60is provided in the fixing unit30by applying the fixing unit30of the first exemplary embodiment as illustrated inFIG.7A. This arrangement makes it possible to downsize the post-processing apparatus9as compared to the post-processing apparatus109including the air duct160as illustrated inFIG.7B. This arrangement makes it also possible to efficiently suction the vapor generated from the recording material S after passing through the fixing nip portion N and to reduce the dew condensation from being generated in the entire region downstream in the conveyance direction of the fixing nip portion N.

The image forming apparatus1described above in the exemplary embodiments have had a configuration in which the image forming units PY, PM, PC and PK configured to form a toner image and a fixing unit30configured to fix the toner image on a recording material are stored in the same casing. However, the present disclosure is not limited to such configuration and has the same effect even if the configuration of the present disclosure is adopted to a configuration of an image forming apparatus201in which a first apparatus202having a casing including an image forming units PY. PM, PC and PK is combined with a second apparatus203having a casing including a fixing unit30as illustrated inFIG.9. In this case, an apparatus body201aof the image forming apparatus201is formed by combining a body of the first apparatus202and a body of the second apparatus203.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2020-123051, filed Jul. 17, 2020 which is hereby incorporated by reference herein in its entirety.