JP2011075839A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which prevents a sticking phenomenon on a paper ejection tray by spraying air to paper in a conveyance path to cool the paper, thereby cooling the paper in an early stage, and prevents turn-up of the paper, fold of the paper, breakage of the paper and jamming of the paper caused by influence on conveyance of the paper by spraying the air to the paper in the conveyance path. <P>SOLUTION: A cooling duct 78 is arranged between a first conveying roller pair 60 and a second conveying roller pair 63 in a second conveyance path 43. When the paper is held by the first conveying roller pair 60 or the second conveying roller pair 63, the paper is corrugated in a direction orthogonal to a conveying direction by drum-like driven rollers 61 and 64. When the paper is held by at least any of the first conveying roller pair 60 and the second conveying roller pair 63, rotation of a cooling fan 77 is started at prescribed rotational speed, to send cooling air by a prescribed air amount. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile machine, and more particularly to an image forming apparatus that cools a sheet heated by a fixing unit.

  In an electronic copying type image forming apparatus, a toner image formed on a photoreceptor is transferred to a sheet by a transfer unit. The sheet on which the toner image is transferred is sent to a fixing unit, and heat and pressure are applied to the fixing unit, whereby the toner image is fixed on the sheet. Thereafter, the paper is discharged from the paper discharge unit to the paper discharge tray and stacked on the paper discharge tray.

  However, if the paper is discharged as it is without being cooled, the paper stacked on the paper output tray is not cooled sufficiently and the temperature is high. There has been a phenomenon of adhesion (hereinafter, this phenomenon is referred to as a sticking phenomenon). This sticking phenomenon is particularly remarkable during double-sided printing and high-speed printing.

  To alleviate this sticking phenomenon, it is conceivable to increase the length of the conveyance path from the fixing unit to the paper discharge tray to increase the cooling time. However, as in recent years, the image forming apparatus has been downsized. Therefore, this method can no longer be adopted.

  Therefore, air is blown onto the paper after passing through the fixing device in the conveyance path to cool the paper (see Patent Documents 1 and 2 below).

JP-A-4-345187 JP-A-8-171338

  However, in the image forming apparatuses described in Patent Document 1 and Patent Document 2, the timing of blowing air and the amount of air on the paper in the transport path are not taken into consideration, so that the front edge of the paper may bend by blowing air onto the paper. However, the influence on the sheet conveyance property such that the leading end of the sheet does not properly enter the nip of the roller pair and the sheet breaks or breaks or a jam occurs is not taken into consideration.

  The present invention has been made in view of the circumstances as described above, and blows and cools air on the paper in the conveyance path to cool the paper at an early stage and prevent the sticking phenomenon on the paper discharge tray. To provide an image forming apparatus capable of preventing paper curling, paper folding, paper breakage, and paper jamming by affecting the paper transportability by blowing air onto the paper in the transport path. It is.

The present invention provides an image forming apparatus including an image forming unit that forms an image on a recording medium, and a fixing unit that heat-fixes the image on the recording medium after the image is formed.
A post-fixing conveyance path for conveying the recording medium after heat-fixing by the fixing unit, a discharge conveyance path connected to the post-fixing conveyance path and conveyed to a discharge port, and a conveyance roller pair provided in the discharge conveyance path; A cooling mechanism that is arranged in the discharge conveyance path and sends cooling air,
2. The image forming apparatus according to claim 1, wherein the conveying roller pair causes the recording medium to wave in a direction orthogonal to the recording medium conveying direction when the recording medium is sandwiched.

  As a result, even if cooling air is blown onto the recording medium to cool the recording medium, the recording medium is difficult to break. Folds, jams, etc.) are unlikely to occur.

  In addition, the transport roller pair includes two pairs, and the cooling mechanism is provided between them, and the undulation positions of the upstream and downstream transport roller pairs on the recording medium are the same with respect to the cooling mechanism. It is characterized by.

  As a result, the wavy position on the recording medium in the direction orthogonal to the recording medium conveyance direction is the same for the pair of conveyance rollers immediately upstream and the pair of conveyance rollers immediately downstream. It is difficult for the recording medium to bite.

  The cooling mechanism may vary the amount of cooling air according to the type of recording medium.

  As a result, it is possible to further prevent the recording medium from being folded and to reduce the degree of undulation, and to reduce damage to the recording medium due to undulation.

  Further, the cooling mechanism is arranged adjacent to the downstream side of the pair of transport rollers.

  As a result, air is blown onto the recording medium near the pair of conveying rollers that undulate the recording medium, so that the recording medium is unlikely to break.

  According to the present invention, in the configuration in which the cooling air of the sheet is blown downstream of the pair of conveyance rollers that sandwich the recording medium, the pair of conveyance rollers that sandwich the sheet causes the sheet to wave in the sheet conveyance direction. The stiffness is increased, and it is possible to prevent improper clamping to the roller on the downstream side of the front end of the sheet.

1 is a schematic cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows one Embodiment of the cooling mechanism in a 2nd conveyance path. It is a perspective view which shows one Embodiment of the cooling mechanism in a 2nd conveyance path. It is a figure which shows the cooling duct of this embodiment, (a) is a top view, (b) is sectional drawing in AA. 2 is a block diagram relating to a cooling mechanism of the image forming apparatus. FIG. It is a flowchart which shows the procedure of cooling to a paper. It is explanatory drawing which shows the paper conveyance and cooling in the case of duplex printing completed in single-sided printing mode or double-sided printing mode. It is explanatory drawing which shows the paper conveyance and cooling in the case of the single-sided printing of double-sided printing mode.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.

FIG. 1 is a schematic sectional view showing the structure of the image forming apparatus X according to the embodiment of the present invention.
First, the configuration of an image forming apparatus X according to an embodiment of the present disclosure will be described with reference to FIG. The image forming apparatus X is a multifunction machine having both a copying function and a printer function.
The image forming apparatus X has a copier mode (copying mode), a printer mode, and a FAX mode as print modes. An operation input from an operation unit (not shown) or a print job from an external host device such as a personal computer. Is selected by a control unit (not shown) in FIG. 1 (a control unit 101 in FIG. 5 to be described later).

  As shown in FIG. 1, the image forming apparatus X is roughly divided into an uppermost document reading unit 1, a printer unit (image forming unit) 2 disposed below the uppermost document reading unit 1, and a lower unit. And a paper feed unit 3.

  The manuscript reading unit 1 performs a copying operation when a start key on the operation panel is operated after inputting a condition input key (number of printed sheets / printing magnification, etc.) on an operation panel (not shown) disposed on the front surface of the apparatus. And the image of the document placed on the platen glass 31 is read. That is, the copy lamp 32a (light source) of the copy lamp unit 32 is turned on, and exposure of the document is started while the copy lamp unit 32 moves horizontally. Irradiation light applied to the document by the copy lamp 32a becomes reflected light (reflected light from the document) including image information of the document, and the reflected light is transmitted from the first mirror 32b provided in the copy lamp unit 32 to the second light. Reading is performed by inputting to the CCD 36 from the mirror 33, the third mirror 34, and the optical lens 35.

  The image information read in this manner is converted into an electrical signal by a CCD circuit provided in a control unit (not shown), and the image information signal is subjected to image processing under a set condition. The data is transmitted to the optical scanning unit 6 as print data.

  The printer unit 2 includes an electrophotographic process unit 20 that forms an image with a developer (toner) on a recording medium (paper), and a recording medium after the image is formed between a fixing roller 21a (heating roller) and a pressure roller 21b. And a fixing unit 21 (fixing unit) that heats and fixes an image (toner image) on the recording medium. A heater is provided inside the fixing roller 21a. The power supplied to the heater is such that the temperature detected by the temperature sensor 21c for detecting the temperature of the fixing roller 21a is maintained at a predetermined fixing temperature. It is controlled by a control unit (not shown).

  The electrophotographic process unit 20 is disposed substantially at the center of the electrophotographic process unit 20, and includes the photosensitive drum 4, a charging unit 5, an optical scanning unit 6, and a developing unit 7 disposed around the photosensitive drum 4. A transfer unit 8 and a cleaning unit 9 are provided.

  The charging unit 5 charges the surface of the photosensitive drum 4 uniformly, and the optical scanning unit 6 writes an electrostatic latent image by scanning a light image on the uniformly charged photosensitive drum 4. The developing unit 7 visualizes the electrostatic latent image written according to the print data by the optical scanning unit 6 with a developer.

  The transfer unit 8 transfers an image recorded and reproduced on the photosensitive drum 4 onto a recording medium such as recording paper, and the cleaning unit 9 removes the developer remaining on the photosensitive drum 4. Thus, a new image can be recorded on the photosensitive drum 4.

  The residual developer removed by the cleaning unit 9 is collected in the developer supply unit 10 of the developing unit 7 and recycled. Note that the image forming apparatus according to the present invention is not limited to the one provided with the process of recycling the residual developer as described above, and may be an image forming apparatus that is collected and discarded.

  In addition, the paper feed unit 3 includes paper feed trays (recording medium supply units) 11, 12, 13, and 14 on which a plurality of recording media (recording paper and the like) are set. For example, the paper can be sorted and accommodated in the paper feed trays 11 to 14 for each size.

  The paper feed tray 11 and the paper feed tray 12 are arranged in parallel with each other, the paper feed tray 13 is arranged below them, and the paper feed tray 14 is arranged below them. Here, the respective capacities of the paper feed tray 13 and the paper feed tray 14 are configured to have the same capacity. On the other hand, the capacities of the paper feed tray 11 and the paper feed tray 12 are configured to be larger than the capacities of the paper feed tray 13 and the paper feed tray 14.

  The paper feed unit 3 includes a fourth transport path 15 and a fifth transport path 16 in order to transport paper (recording media) stored in the paper feed trays 11 to 14 toward the printer section 2. ing. The fourth transport path 15 is for transporting the paper stored in the paper feed trays 11, 13, and 14 toward the printer unit 2, and the fifth transport path 16 is the paper stored in the paper feed tray 12. Is conveyed toward the printer unit 2.

  The fourth conveyance path 15 extends in the substantially vertical direction along the frame 17 of the paper feeding unit 3. On the other hand, the fifth conveyance path 16 extends in a substantially horizontal direction along the frame 17. In this way, the paper feed trays 11 to 14, the fourth transport path 15, and the fifth transport path 16 are efficiently arranged inside the paper feed unit section 3, and space saving of the paper feed unit section 3 is achieved. Is realized.

  When paper is set in each of the paper feed trays 11 to 14, the target paper feed trays 11 to 14 are pulled out toward the front side of the main body of the image forming apparatus X to replenish the paper.

  When image formation is performed on the recording medium in the image forming apparatus X, one tray is selected from the paper feed trays 11 to 14, and the sheets are separated and carried out one by one from the selected tray. .

  The paper (recording medium) carried out (supplied) from the paper feed trays 11 to 14 passes through the fourth or fifth transport path 15, 16 and then is transported upward in the third transport path 41 to be photoreceptor drum 4. And the transfer unit 8. Then, the image recorded and reproduced on the photosensitive drum 4 by the transfer unit 8 is transferred to the supplied paper. The sheet on which the image has been formed is conveyed to a fixing unit 21 (fixing unit) disposed further upward, and the toner image is heated and fixed in the fixing unit 21.

  Then, the paper after the heat fixing by the fixing unit 21 is guided further upward by being sent into the first transport path (post-fixing transport path) 42, and is further disposed above the fixing unit 21. Then, it is transported to the second transport path 43. As will be described later, the second transport path 43 is a discharge transport path and also a switchback transport path in double-sided printing.

  The second transport path 43 is a path that transports the paper (heat-fixed paper) that has passed through the first transport path 42 while changing the direction substantially in the horizontal direction. The sheet is discharged to 2a or sent to a post-processing device (not shown), or the sheet is recirculated to the sixth conveyance path (double-side conveyance path) 44 by switchback, and image formation is performed on both sides of the sheet.

  In the case of a type in which heat fixing is performed while conveying a sheet upward as in the image forming apparatus X, the sheet is raised (conveyed upward), and high-temperature air generated in the fixing unit 21 is also generated. As a result, the sheet after heat fixing is difficult to cool. Further, a portion of the original reading unit 1 (an example of the image reading unit) that is the stop position of the copy lamp unit 32 is above the first conveyance path 42 and the second conveyance path 43 (that is, the fixing unit 21). Since the heated air by the fixing unit 21 rises, the temperature tends to become abnormally high, which causes a failure of the copy lamp unit 32.

  In view of this, in the image forming apparatus X, an exhaust duct 51 is disposed between the second conveyance path 43 and the copy lamp unit 32 (stop position) portion of the document reading unit 1, and the second conveyance is performed therethrough. The air above the passage 43 is configured to be forcibly exhausted. In other words, the air above the second conveyance path 43 is guided to the side surface (the left side surface in FIG. 1) of the image forming apparatus X from the opening provided below the exhaust duct 51 and on the side surface. The exhaust fan 52 provided forcibly exhausts the apparatus outside (other positions) (the exhaust duct 51 and the exhaust fan 52 are examples of the exhaust unit).

  The exhaust duct 51 is disposed with respect to the fixing unit 21 via the second transport path 43, so that the second transport path 43 and the paper passing therethrough serve as a heat insulating layer. Compared with the case where an exhaust duct is arranged in the vicinity of the fixing unit 21 as described above, the fixing unit 21 (in order to maintain the fixing temperature without taking (cooling) heat from the fixing unit 21 more than necessary). The power consumption of the heater is not increased.

The exhaust duct 51 in the present embodiment guides air from the position above the second conveyance path 43 to the outside of the apparatus (side surface). It is configured to circulate all or a part of the air at the position above the second conveyance path 43 to the fixing unit 21 (an example of the other position) to further reduce power consumption of the fixing unit 21. Is also possible.
Here, the exhaust duct 51 is formed by a support member 50 that supports the document reading section 1 (image reading means).

  The second transport path 43 is provided with a cooling mechanism for cooling the paper, which will be described in detail below.

  2 is a configuration diagram showing an embodiment of a cooling mechanism in the second transport path 43, FIG. 3 is a perspective view showing an embodiment of a cooling mechanism in the second transport path 43, and FIG. 4 is a cooling duct of the embodiment. FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along AA.

  As shown in FIG. 2, each of the transport paths 42, 43, 44 includes an upper transport guide 71 and a lower transport guide 72, and the paper P is transported between the upper transport guide 71 and the lower transport guide 72. The second conveyance path 43 is provided with a first conveyance roller pair 60 and a second conveyance roller pair 63 at a predetermined interval, and a tip of the second conveyance roller pair 63 is a paper discharge port 80. The distance L1 between the nip of the first transport roller pair 60 and the nip of the second transport roller pair 63 is shorter than the minimum sheet length to be used. The first transport roller pair 60 includes an upper driven roller 61 and a lower drive roller 62, and the second transport roller 63 includes an upper driven roller 64 and a lower drive roller 65. As shown in FIG. 3, two pairs of the first conveyance roller pair 60 and the second conveyance roller 63 are provided in the roller rotation axis direction (paper width direction). The paper P is sandwiched between the driven rollers 61 and 64 and the driving rollers 62 and 65 and is conveyed to the discharge port 80 by the rotational driving of the driving rollers 62 and 65.

  Here, as shown in FIG. 3, the driven rollers 61 and 65 have a drum-like shape in which both end sides of the cylindrical portion protrude. For this reason, when the paper is sandwiched by the drive rollers 62 and 65, the paper P is waved in the direction orthogonal to the transport direction, and the paper is bent when the air is blown by the cooling duct 78. To prevent. Thereby, even if the air volume is increased, the paper transportability is not impaired. Since the positions of the driven roller 61 of the first transport roller pair 60 and the driven roller 64 of the second transport roller pair 63 in the direction orthogonal to the paper transport direction are the same, the corrugated position of the paper is the same. Accordingly, it is difficult for the second conveyance roller pair 63 to cause a biting defect when the sheet is conveyed from the first conveyance roller 60 to the second conveyance roller 63.

  Further, as shown in FIG. 2, a flat portion is provided in the horizontal direction at least by a predetermined length L2 from the connection portion of the first conveyance path 42 and the second conveyance path 43 to the first conveyance roller pair 60. This is intended to increase the cooling effect of the paper conveyed from the upstream side by allowing the cooling air to easily flow upstream along the second conveyance path 43.

  Also connected to the second transport path 43 are a first transport path 42 for transporting the paper from the fixing unit 21 and a sixth transport path 44 for printing the back side of the paper by switching back and recirculating the paper. Has been. And the gate 73 is attached to this connection part. The gate 73 is rotatably attached, and as shown in FIG. 2, the gate 73 is rotated upward to connect the transport path 42 and the transport path 43 (this position of the gate 73 is defined as a first position). Further, the sheet can be guided by rotating downward to connect the conveyance path 43 and the conveyance path 44 (this position of the gate 73 is set as the second position).

A first paper sensor 74 is provided on the upstream side of the first transport roller pair 60, and a second paper sensor 75 is provided on the downstream side of the second transport roller. These paper sensors 74 and 75 have a light emitting part and a light receiving part above and below the second transport path 43, and detect the presence or absence of paper in the transport path. The first sheet sensor 74 shares a sheet switchback timing sensor. The second paper sensor 75 detects completion of paper discharge by detecting the trailing edge of the paper.
The paper sensor may be an actuator type sensor.

The second transport path 43 is provided with a cooling mechanism 76, which cools the transported paper by blowing cooling air. The cooling mechanism 76 includes a cooling fan 77 and a cooling duct 78.
The cooling duct 78 is disposed between the first conveyance roller pair 60 and the second conveyance roller pair 63 and guides air from the outside to the sheet P being conveyed. As shown in FIGS. 3 and 4, the cooling duct 78 is a rectangular frame, and has a length that can cool the entire width of the paper (paper width in the direction perpendicular to the transport direction). As shown in FIG. 4, the driven roller 61 has a structure in which a rib 80 is formed in the transport direction and intermittently opens to form an air outlet 79, as shown in FIG. Also serves as. The cooling duct 78 is arranged adjacent to the downstream side of the driven roller 61 of the first transport roller 60.

  As shown in FIG. 2, the upper conveyance guide 71 has an opening in which the cooling duct 78 is installed, from which cooling air guided to the cooling duct 78 is sent to a place near the subordinate roller 61 to perform the first conveyance. The sheet sandwiched between the roller pair 60 is cooled. For this reason, the paper is not easily folded. Air is taken from the outside of the apparatus and is sent to the cooling duct 78 by the cooling fan 77.

  FIG. 5 is a block diagram relating to a cooling mechanism of the image forming apparatus. The image forming apparatus is controlled by the control unit 101 as described above. That is, the control unit 101 controls the conveyance roller pairs 60 and 63, the paper sensors 74 and 75, the gate 73, and the cooling fan 77 according to the detection values by the paper sensors 74 and 75 and the preset values registered in the storage unit 102. . In addition, timers T1 and T2 described later are set.

Next, the cooling operation by the cooling mechanism will be described.
FIG. 6 is a flowchart showing a procedure for cooling the paper, FIG. 7 is an explanatory diagram showing paper conveyance and cooling in the case of duplex printing in the simplex printing mode or duplex printing mode, and FIG. It is explanatory drawing which shows the paper conveyance and cooling in the case of printing.

  As shown in FIG. 7A, when starting the sheet conveyance, the control unit 101 rotates the gate 73 upward to close the sixth conveyance path 44 as the first position, and the first conveyance path 42 and the second conveyance path. The conveyance path 43 is communicated, and the conveyance of the sheet that has passed through the fixing unit 21 from the first conveyance path 42 to the second conveyance path 43 is started (step S1). At this time, blowing by the cooling mechanism 76 is stopped. When the first sheet sensor 74 detects the leading edge of the sheet (step S2; Yes), the control unit 101 that has received the detection signal sets the timer T1 (step S3). Since the first paper sensor 74 is disposed outside the cooling duct 78 upstream of the nip of the first transport roller pair 60, the time required for the front end of the paper to be caught in the nip of the first transport roller pair 60 is set to the timer T1. It is what. The set value of the timer T1 is registered in advance in the storage unit 102, and the control unit 101 reads it from the storage unit 102 and sets the timer T1.

  When the timer T1 is started (step S4) and the timer T1 counts up the set value (predetermined time) (step S5; Yes), as shown in FIG. The rotation of the cooling fan 77 is started, and air blowing is started with a predetermined air blowing amount (step S6). In this case, setting values such as the rotation speed of the cooling fan 77 that secures the air volume are stored in the storage unit 102 in advance, and the control unit 101 reads out this value and drives the cooling fan 77. The set value of the air volume is set to a value that does not cause a paper conveyance failure. In a state where the sheet is sandwiched between the first conveying roller pair 60, the sheet P is waved in a direction perpendicular to the conveying direction by the driven roller 61 on the drum and the drive roller 62 having a normal shape. Therefore, the stiffness of the paper becomes strong, the paper does not bend even with a certain amount of blown air, the paper is not easily bent due to the blown air, and poor transportability can be prevented.

  The air flow rate is a value corresponding to the type of paper (paper size, paper thickness, paper eye (whether the fiber direction is parallel or perpendicular to the conveyance direction, etc.)), It is set so as to prevent it, thereby preventing a poor paper transportability. In this case, setting values such as the rotation speed of the cooling fan 77 are stored in advance in the storage unit 102, and the control unit 101 reads out this value according to the type of paper and drives the cooling fan 77. The paper type may be input from the operation unit by the user when the paper is stored in the paper feed tray, or may be detected by a detection sensor and automatically set by the control unit 101.

  The sheet conveyance is continued, and as shown in FIG. 7C, the sheet P is sandwiched between the first conveyance roller pair 60 and the second conveyance roller pair 63, and the blowing is continued with the set air volume.

  Next, as shown in FIG. 7D, the control unit 101 confirms whether the first paper sensor 74 has detected the trailing edge of the paper P (step S7). When the trailing edge of the paper P is detected (step S7; Yes), the control unit 101 confirms whether or not the single-sided printing mode is set (step S8). If it is the single-sided printing mode (step S8; Yes), the timer T2 is set (step S9). Here, the timer T2 is the time until the paper passes through the outlet 79. The control unit 101 starts the timer T2 (step S10) and confirms whether the timer T2 has been increased (step S11). As shown in FIG. 7E, the blowing is continued at the set air volume until the timer T2 counts up the set value. When the timer T2 counts up the set value (step S11; Yes), as shown in FIG. 7 (f), since the sheet P has passed through the blowout port 79, the blowing is interrupted (step S12).

  It is confirmed whether or not all sheets to be printed have passed through the blowout opening 79 (step S13). If all the sheets have passed through the blowout opening 79, the process is terminated. The paper P is transported.

  In step S8, if it is not the single-sided printing mode, it is confirmed in step S14 whether the paper P is in the double-sided printing mode. If it is not the one-sided paper P in the duplex printing mode, the process proceeds to step S9, and the timer T2 is set. In the case of one-sided paper P in the duplex printing mode, the first conveyance roller pair 60 and the second conveyance roller pair 63 are stopped (step S15), and the gate 73 is rotated downward as shown in FIG. In the second position (step S16), the second transport path 43 and the sixth transport path 44 are communicated. Then, as shown in FIG. 8B, the first transport roller pair 60 and the second transport roller pair 63 are driven in reverse (step S17). As shown in FIG. 8C, even when the sheet P passes through the second conveyance roller 63 and is held only by the first conveyance roller 60, the control unit 101 sets the cooling fan 77 at the set air volume. Continue driving. The control unit 101 confirms whether the first sheet sensor 74 has detected the trailing edge of the sheet (step S18), and proceeds to step S12 when the trailing edge of the sheet is detected.

  Thus, before the front end of the sheet is nipped by the nip of the first conveying roller pair 60, the air blowing is stopped, and when the sheet is nipped by the first conveying roller pair 60, the amount of air blown by the cooling mechanism is set. Cool down. Since the single-sided printed paper in the duplex printing mode is cooled during both the period of carrying into the switchback path and the time of carrying out from the switchback path, the paper can be sufficiently cooled and heat is not accumulated in the apparatus.

  Note that the paper is sandwiched between conveyance roller pairs 60 and 63 having drum-shaped driven rollers 61 and 64, thereby undulating in a direction orthogonal to the conveyance direction, and becomes stiff and paper due to air blowing. Poor transportability (paper curling, paper folding, jamming, etc.) hardly occurs.

X image forming apparatus 20 electrophotographic process section 21 fixing unit 42 first transport path 43 second transport path 44 sixth transport path 50 support members 60, 63 transport roller pair 61, 64 driven roller 62, 65 driving roller 71 upper transport guide 72 Lower conveyance guide 80 Discharge port 73 Gates 74 and 75 Paper sensor 76 Cooling mechanism 77 Cooling fan 78 Cooling duct 79 Air outlet 80 Rib

Claims (4)

An image forming apparatus comprising: an image forming unit that forms an image on a recording medium; and a fixing unit that heat-fixes the image on the recording medium after the image is formed.
A post-fixing conveyance path for conveying the recording medium after heat fixing by the fixing unit;
A discharge transport path connected to the post-fixing transport path and transported to a discharge port;
A pair of transport rollers provided in the discharge transport path;
A cooling mechanism that is arranged in the discharge conveyance path and sends cooling air;
With
2. The image forming apparatus according to claim 1, wherein the conveying roller pair causes the recording medium to wave in a direction orthogonal to the recording medium conveying direction when the recording medium is sandwiched. The transport roller pair is two sets, and the cooling mechanism is provided between them.
The image forming apparatus according to claim 1, wherein the waviness position on the recording medium by the upstream and downstream conveying roller pairs is the same with respect to the cooling mechanism.   The image forming apparatus according to claim 1, wherein the cooling mechanism varies a cooling air volume according to a type of the recording medium.   The image forming apparatus according to claim 1, wherein the cooling mechanism is disposed adjacent to a downstream side of the pair of conveying rollers.

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