JP6697424B2 - Image forming device - Google Patents

Description

  The present invention relates to an image forming apparatus.

Conventionally, as images forming device, configuration for discharging the sheet having an image formed by the image forming unit in the casing from the discharge port to the discharge portion of the housing outer is known (Patent Document 1, etc.).

As this type of image forming apparatus, a suction device to one side wall of the outside in the width direction of the the paper conveyance path provided, are also known in which exhausting to the outside by sucking air in the sheet conveying path.

In the image forming apparatus including the suction device, it can be considered that the air in the paper transport path can be suppressed from being exhausted to the outside from the paper discharge port .
However, an image forming apparatus including the above-mentioned suction device, for sucking air from one of the outer width direction of the sheet conveying path, the sheet conveying path air, on the side not provided with the contact Keru suction device in the width direction It flows from the end toward the end on the side where the suction device is provided .

In order to solve the above-mentioned problems, the invention of claim 1 provides a conveyance path for guiding a recording medium, an image forming unit for forming an image on the recording medium, a housing for accommodating the image forming unit, and In an image forming apparatus provided with a discharge port for discharging a recording medium from the housing, a space inside the housing, which is a discharge port inner space including at least a part of the transport path and the discharge port, An opening for putting the recording medium into the inner space of the outlet and an exhaust gas for guiding the gas in the inner space of the outlet to the outside of the housing from a suction hole provided at a position different from the outlet. A passage and an exhaust means provided in the exhaust passage for exhausting the gas to the outside of the housing, and the suction hole is provided at a position facing the transport passage in the inner space of the outlet. A heating means for heating the recording medium is provided on the upstream side of the opening in the conveyance direction of the recording medium, and when the exhaust means performs an exhaust operation, the gas that has passed through the opening and the exhaust port. Both of the gas having passed through and flow into the exhaust port inner space.

According to the present invention, it is possible to uniformly suck the gas in the exhaust port inner space over the entire width direction while suppressing the gas in the exhaust port inner space from being exhausted to the outside from the exhaust port. It has an excellent effect.

FIG. 3 is a schematic enlarged view of the vicinity of a fixing unit and a paper discharge port of the copying machine of the present embodiment. 1 is a schematic configuration diagram of an entire copying machine according to an embodiment. FIG. 3 is an enlarged perspective view of the vicinity of a sheet conveyance path between the fixing unit and the sheet discharge port. The schematic top view of an exhaust duct. FIG. 3 is an explanatory diagram of a configuration in which an exterior cover is provided in a cooling mechanism including an intake hole and a suction fan to form a unit structure cooling unit. FIG. 10 is a schematic enlarged view of a fixing unit of a conventional copying machine that performs in-body discharge and a discharge port and its vicinity.

  An embodiment of an electrophotographic copying machine (hereinafter, simply referred to as "copying machine 100") will be described below as an image forming apparatus to which the present invention is applied. In the present embodiment, a monochrome image forming apparatus will be described as an example of the copying machine 100, but the present invention can be similarly applied to a known color image forming apparatus. Further, the copying machine 100 is a tabletop compact image forming apparatus, but the present invention is also applicable to a relatively large image forming apparatus mounted on the floor.

FIG. 2 is a schematic configuration diagram of the entire copying machine 100 of this embodiment.
The copying machine 100 includes a document reading device 2 on a printer unit 1 that forms an image, and a document pressing plate 3 on the document reading device 2. Further, below the printer unit 1, there is a paper feeding device 5 having a paper feeding tray 4 that can be pulled out in the front direction, which is the front side in FIG.

  The arrow “R1” in FIG. 2 indicates the conveyance path of the paper P stored in the paper feed tray 4. The sheets P stored and stacked in the sheet feeding tray 4 are pushed up by the movable bottom plate 6 on the front end side which is the right side in FIG. 2, and the feeding force is rotatively driven toward the upper right direction in FIG. Granted. The sheets of paper P are separated one by one by the friction pad 8, and the separated one sheet of paper P is moved upward by a registration roller pair 9 composed of two rollers which are arranged to face each other and are rotationally driven. It is conveyed vertically to the transfer position.

  The surface of the drum-shaped photoconductor 11 is uniformly charged by the charging roller 15 while rotating, and an electrostatic latent image is written on the surface by the laser light emitted from the writing unit 12. The electrostatic latent image becomes a toner image by being developed by the developing device 10. The toner image reaches the transfer position where the photoconductor 11 and the transfer roller 13 face each other by the rotation of the photoconductor 11, and a toner image is formed on the left surface of the paper P that passes through the transfer position in FIG. Toner is supplied from a toner bottle 14 arranged above the writing unit 12 in FIG. 2 to the developing device 10 that consumes toner by development.

  The sheet P on which the toner image is formed is heated and heated by the heat fixing roller pair 16 whose temperature is raised by the heat of the heater in the fixing unit 17 including the heat fixing roller pair 16 and the heater located above the transfer position. Pressure is applied to fix the toner image. The paper P that has passed through the fixing unit 17 is ejected from the paper ejection port 180 to the outside of the casing 19 of the printer unit 1 by the paper ejection roller pair 18 composed of two rotating rollers. The outside of the paper discharge port 180 is a space provided in the lower portion of the document reading device 2 and a paper discharge storage unit 20 provided in the body of the copying machine 100. That is, the paper P that has passed through the paper exit 180 is inside the body of the copying machine 100 formed by the image forming unit (printer unit 1) and the image reading unit (original reading device 2) that are the main body of the image forming apparatus. The sheet is discharged to the discharged sheet storage section 20 as an in-body sheet discharging section provided in the. The paper P discharged toward the discharged paper storage unit 20 forms the lower surface of the discharged paper storage unit 20, and is stacked on the paper discharge tray 21 that receives the discharged paper so that the image surface faces downward.

The copying machine 100 has another paper feed unit in addition to the paper feed tray 4. This is called a "manual paper feed section", and is a unit for feeding the paper P set on the manual paper feed tray 22 opened by rotating rightward in FIG. The arrow “R2” in FIG. 2 indicates the conveyance path of the paper P set on the manual feed tray 22.
The paper P set on the manual feed tray 22 is sent out in the left direction in FIG. 2 by the rotation of the calling roller 24 which can be swung in the vertical direction, and is guided to the registration roller pair 9. The subsequent steps are the same as the case of the stored paper P that has been merged into the transport path indicated by the arrow “R1” in FIG. 2 and stored in the paper feed tray 4.

Next, the transport path and operation in the case of double-sided printing in the copying machine 100 will be described.
The dashed arrow "R3" in FIG. 2 indicates the reversal path through which the paper P to be printed on both sides passes after an image is formed on one side.

  As in the above-described one-sided printing, the sheet P on which an image is formed on one side is sandwiched between the pair of sheet discharge rollers 18, and the front half thereof is discharged to the sheet discharge storage section 20. Then, the conveyance is temporarily stopped at the point where the rear end of the paper P has passed the front end of the reverse path switching claw 26. When the trailing edge of the sheet P in this case exceeds the tip of the reversing path switching claw 26, it moves to a position higher than the tip of the reversing path switching claw 26 due to the rigidity of the sheet. When the pair of discharge rollers 18 is reversed here, the sheet passes above the reversal path switching claw 26 as indicated by the broken line arrow "R3" in FIG. 2 and is guided downward by the guide member in the reversal path. The double-sided conveyance roller pair 27 conveys the sheet further downward.

  The sheet P that has passed the double-sided transport roller pair 27 is curvedly transported by the guide member in the reversing path as indicated by the broken line arrow “R3” in FIG. 2, and is again guided between the registration roller pair 9. In this way, an image is formed on the surface of the paper P opposite to the surface on which the paper P has been printed, whereby double-sided printing becomes possible. The double-sided printed paper P is discharged onto the paper discharge tray 21.

  2 is a columnar member provided only on the front side on the left side in FIG. 2, and has a role of holding the document reading device 2. ing. The printed paper P discharged onto the paper discharge tray 21 is normally taken out from the front side, which is the front side in FIG. 2, and if it is not possible, it is taken out from the left side. It has become.

  In the copying machine 100 shown in FIG. 2, when the fixing unit 17 heats and fixes the sheet P, the air around the fixing unit 17 is also heated and the temperature rises. Further, the copying machine 100 shown in FIG. 2 is an electrophotographic image forming apparatus in which the discharge tray 21 is provided inside the body of the apparatus body and the installation space can be reduced. In such an image forming apparatus, after forming an image on a sheet, the image is passed through the fixing section and discharged to a sheet discharge tray. Therefore, the air heated in the fixing unit is discharged together with the paper to the in-body discharge unit, and the temperature of the air in the in-body discharge unit rises, forming the periphery of the in-body discharge unit in the image forming apparatus. There is a risk that the temperature of the part will rise.

FIG. 6 is a schematic enlarged view showing the flow of air in the vicinity of the fixing unit 17 and the paper discharge port 180 of the conventional copying machine 100 that discharges paper from the inside of the cylinder.
Dashed arrows “H1” to “H3” in FIG. 6 indicate the flow of air heated by the fixing unit 17 and having an increased temperature.
The air in the vicinity of the fixing unit 17 is heated and rises together with the paper P during heat fixing (H1). Then, the temperature-increased air that has reached the discharge port inner space 50 near the uppermost portion of the casing 19 flows toward the discharge port 180 that has a flow toward the outside (H2), and together with the paper P, the discharge port 180. The sheet is discharged from the discharged sheet storage section 20 (H3).

  In a device such as the copying machine 100, in which the paper P on which an image is formed is discharged to the paper discharge storage unit 20 arranged in the apparatus body, when the temperature-increased air is discharged together with the paper P, as shown in FIG. As indicated by “Ha”, the air whose temperature has risen is collected in the space of the discharged sheet storage section 20. As a result, the temperature of the air inside the discharged paper storage unit 20 becomes high. When the temperature of the air in the discharged paper storage unit 20 becomes high, the heat gradually moves to the surroundings, and the temperature inside the copying machine 100 also rises.

  As a problem caused by an increase in the temperature inside the copying machine 100, for example, if the temperature of the document reading device 2 rises, the optical system may be distorted, and the original image may be read in a distorted state, and the image quality may deteriorate. .. Further, when the temperature of the printer unit 1 rises, the toner is melted inside and then solidified to generate fixed toner or aggregated toner, which may deteriorate the image quality. In addition, if the temperature of the air in the discharged paper storage unit 20 is high, when the paper P on which the image is formed is taken out of the discharged paper storage unit 20, the user who is in contact with the heated air becomes uncomfortable. You may feel it.

  As a conventional image forming apparatus, a suction device is provided on a rear plate (a wall on the back side in FIG. 6) of the copying machine 100, which is on the outer side in the width direction of the sheet conveying path between the fixing unit 17 and the sheet discharge port 180. The air in the casing 19 is sucked and discharged to the outside. In this apparatus, air is taken in through an opening provided in the front plate (front wall in FIG. 6) of the copying machine 100, and outside air passes through a space between the fixing unit 17 and the paper exit 180 near the paper transport path. Then, the air is exhausted from the back side provided with the suction device.

In such a configuration, the warm air on the front side of the device flows to the rear side of the device, which inevitably raises the temperature on the rear side, and the air becomes warmer toward the rear side of the device body. Will occur. With such a configuration, if the temperature of the air is to be sufficiently reduced over the entire width direction, it is necessary to set the specifications of the suction device to be high, and the efficiency of suppressing the temperature rise is reduced. Further, the temperature of the air on the front side of the main body of the apparatus, which has the lowest temperature, is excessively lowered, and the heat generated in the fixing unit 17 is transferred to the air whose temperature is lowered, and the vicinity of the fixing unit 17 is overcooled. There is a risk. If the vicinity of the fixing unit 17 is cooled too much, the heater lighting rate of the fixing unit 17 will be increased and the power consumption of the apparatus main body will be increased. Therefore, it is necessary to more efficiently exhaust the air in the paper ejection outlet inner space 50.

Patent Document 1 describes a configuration in which the air in the in-body discharge unit is sucked and discharged from the back side of the image forming apparatus. In such a configuration in which the air in the in-body discharge section is sucked, the air whose temperature has risen can be discharged to the outside of the in-body discharge section, and the air whose temperature has risen stays in the in-body discharge section. Can be prevented. However, since the air whose temperature has risen continues to be discharged from the paper discharge port to the in-body discharge section along with the paper, warm air is always supplied to the in-body discharge section, and the temperature of the air in the in-body discharge section rises. Is not sufficiently suppressed.
Further, Patent Document 1 describes a configuration including an exhaust path for discharging heat and the like from the fixing device to the outside. However, since air is sucked and discharged from one end in the width direction, there is a high temperature in the width direction inside the device from the end on the side where the suction device is not provided to the end on the side where the suction device is provided. There is a risk that a temperature gradient will occur such that a temperature difference will occur between the ends in the width direction.

Next, the characteristic part of the copying machine 100 of this embodiment will be described.
FIG. 1 is a schematic enlarged view of the vicinity of the fixing unit 17 and the paper discharge port 180 of the copying machine 100 of the present embodiment, and FIG. 3 is near the conveyance path of the paper P between the fixing unit 17 and the paper discharge port 180. FIG.

  As shown in FIGS. 1 and 3, the conveyance path between the fixing unit 17 and the paper ejection port 180 includes a pre-ejection upper upstream guide plate 30, a pre-ejection upper downstream guide plate 31, and a pre-ejection sheet. And the lower guide plate 32. As shown in FIG. 3, the paper P in the width direction of the transport path (front-back direction in FIG. 1) passes through the pre-ejection upper upstream guide plate 30 and the pre-ejection upper downstream guide plate 31. The upstream guide hole 30a and the downstream guide hole 31a are provided in the obtained range.

  As shown in FIG. 1, the copying machine 100 includes a duct lower surface plate 190 that shields a space above the fixing unit 17 and forms a lower surface of the exhaust duct 52. The lower surface plate 190 of the duct is provided with an intake hole 45 at a position facing the upper downstream guide plate 31 before discharge, and the suction fan 42 is provided as suction and exhaust means in the exhaust duct 52. The intake holes 45 are provided above the range through which the paper P can pass in the width direction of the transport path (front-back direction in FIG. 1).

By driving the suction fan 42, the air in the exhaust duct 52 is sucked by the suction fan 42, moves to the right in FIG. 1, and is discharged from the exhaust port 53 to the outside of the copying machine 100.
Further, by driving the suction fan 42, a negative pressure acts on the intake hole 45, and the air in the paper ejection outlet inner space 50 moves toward the exhaust duct 52 through the intake hole 45. Due to the movement of the air, a negative pressure also acts on the downstream guide hole 31a, and the air in the transport path passes through the downstream guide hole 31a and moves toward the paper ejection outlet inner space 50. Further, due to the movement of the air, a negative pressure also acts on the paper ejection port 180, and the air in the paper ejection storage unit 20 passes through the paper ejection port 180 and moves toward the conveyance path of the paper P.
By driving the suction fan 42, the movement of the air as described above occurs, so that the discharge path from the discharge storage portion 20 to the conveyance path and the space inside the discharge port as indicated by the double-dashed line arrow “F” in FIG. A flow of air passing through the exhaust duct 52 and the exhaust duct 52 is generated.

  As shown in FIGS. 1 and 3, the copying machine 100 sucks air from the downstream guide hole 31 a and the intake hole 45 provided inside the range through which the paper P can pass in the paper width direction of the transport path. In such a configuration, a temperature gradient occurs in which the temperature is the highest in the vicinity of the downstream guide hole 31a in the sheet width direction of the transport path and is lower as the distance from the downstream guide hole 31a increases. Since the downstream guide hole 31a is provided inside the range in which the sheet P can pass in the sheet width direction of the transport path, one of the both ends in the sheet width direction of the transport path that is farther from the downstream guide hole 31a. The temperature is the lowest near the edge of. At this time, the distance between the hottest part and the coldest part of the conveyance path in the width direction of the paper becomes shorter than that in the case where suction is performed from one end side in the width direction, and the temperature difference in the width direction caused by the temperature gradient is generated. Can be suppressed.

  Further, by providing the downstream guide holes 31a and the intake holes 45 at a plurality of positions in the paper width direction, it is possible to suck air over the entire width direction rather than the structure in which the one end side in the width direction is sucked. Thereby, the air whose temperature inside the transport path or the inside of the discharge port 50 has risen can be uniformly discharged to the outside in the width direction, and the temperature gradient in the width direction of the transport path can be suppressed.

  Further, since the air heated to a high temperature by the heating of the fixing unit 17 is sucked upstream of the paper discharge port 180 and discharged to the outside, the heated air is discharged to the paper discharge storage unit 20. Can be suppressed. As a result, it is possible to suppress the temperature rise of the discharged paper storage unit 20.

In the copying machine 100 of the present embodiment, the suction fan 42 is provided above the range through which the paper P can pass in the width direction of the transport path (front-back direction in FIG. 1). Since the downstream guide hole 31a is provided in the upper part of the transport path that transports the paper P in the horizontal direction, when the suction fan 42 is driven, the downstream guide hole 31a is orthogonal to the transport direction of the paper P and the width direction. Also, it is possible to generate an air flow in a direction orthogonal to each other.
As described above, the copying machine 100 has the suction fan 42 arranged in the widthwise direction of the sheet P through which the sheet P can pass and has a mechanism for sucking air in the direction orthogonal to the sheet conveying direction. As a result, the airflow can be evenly distributed over the entire area in the width direction of the sheet, and the airflow can efficiently perform the intake of the entire sheet width (the double-dashed line arrow “F” in FIG. 1). ) Is made.

  By efficiently sucking the air in the transport path, it is possible to form an airflow from the discharged paper storage unit 20 toward the transport path at the paper discharge port 180. Due to such an air flow, an air flow in the direction opposite to the conveying direction of the paper P is formed in the vicinity of the paper ejection port 180, and the air whose temperature has risen is exhausted together with the paper P from the paper ejection port 180 to the paper ejection storage unit 20. Can be prevented. As a result, it is possible to prevent the temperature in the vicinity of the discharged sheet storage section 20 from rising.

FIG. 4 is a schematic top view of the exhaust duct 52.
As shown in FIG. 4, the copying machine 100 is provided with a plurality of intake holes 45, and the high-temperature air located below is taken in through the intake holes 45, and the exhaust port 53 provided on the right side surface of the main body of the copying machine 100. Exhaust out of the machine. Further, in order to enhance exhaust efficiency, the exhaust duct 52 forming a flow path from the intake hole 45 toward the suction fan 42 is gradually narrowed. When the specifications of the suction fan 42 are high or when a plurality of suction fans 42 are arranged in parallel, the flow path may not be narrowed.

  As shown in FIGS. 3 and 4, by arranging a plurality of the downstream guide holes 31a and the intake holes 45 in the width direction, it is possible to realize a configuration in which the hot air is sucked over the entire width direction. it can. As a result, it is possible to suppress the occurrence of a temperature gradient in the conveyance path or in the width direction of the space 50 inside the discharge port.

The fixing unit 17 also has a function of heat storage for fixing an image formed on a sheet by heat. However, since the copying machine 100 of the present embodiment takes in air from the space between the fixing unit 17 and the paper discharge port 180 and exhausts it to the outside of the apparatus, there is a possibility that the air in the fixing unit 17, which should be at a high temperature, will also be cooled. There is. If the air in the fixing unit 17 is cooled, the heat required for fixing is also removed, so that the lighting rate of the heater is increased and the power consumption of the entire apparatus is also increased.

  On the other hand, in the copying machine 100 of the present embodiment, as shown in FIGS. 1 and 3, a shielding unit that shields the fixing unit upper space 51, which is a space above the fixing unit 17, and the discharge port inner space 50. The wall 43 is provided so that the heat of the fixing unit 17 is not taken away.

  As shown in FIGS. 1 and 3, the position of the shielding wall 43 is provided in the vicinity of the outer side of the upper surface which is the side end surface of the fixing unit 17 on the downstream side in the sheet conveying direction. If the shielding wall 43 is arranged inside the fixing unit 17, it becomes impossible to prevent the movement of high temperature air indicated by “H1” in the drawing. Further, when the position of the shielding wall 43 is past the sheet discharge storage section 20 side, the distance of the air flow in the conveyance path indicated by the two-dot chain line arrow “F” in FIG. 1 cannot be gained and sufficient cooling cannot be performed. I will end up. Therefore, the fixing unit 17 is provided near the outside of the upper surface.

The paper P discharged from the fixing unit 17 is provided with a paper discharge roller pair 18 by a paper discharge upper upper upstream guide plate 30, a paper discharge upper upper downstream guide plate 31, and a paper discharge lower lower guide plate 32. It is guided to the paper ejection port 180. The pre-ejection upper upstream guide plate 30 and the pre-ejection upper downstream guide plate 31 have an upstream guide hole 30a and a downstream guide hole 31a. The airflow generated by driving the suction fan 42 passes through the downstream guide hole 31a to cool the transport path.

  Part of the high-temperature air heated by the fixing unit 17 is carried by the paper P, passes under the shielding wall 43, and flows downstream in the transport direction. The air whose temperature has risen due to the heat of the paper P and the high-temperature air that has passed under the shielding wall 43 together with the paper P are sucked by the suction fan 42 and pass through the downstream guide hole 31a, and the outside of the apparatus. Exhausted to.

The shielding wall 43 is disposed between the upper front guide plate 30 before paper ejection and the upper downstream guide plate 31 before paper ejection, and the downstream side through which the air in the transport path sucked by the suction fan 42 passes. It is located upstream of the guide hole 31a in the transport direction.
As a result, the air heated to a high temperature by the fixing unit 17 is shielded by the shielding wall 43 and stays in the fixing unit upper space 51 except for a part of the air that has passed under the shielding wall 43. Since high-temperature air stays in the fixing unit upper space 51 adjacent to the fixing unit 17, cooling of the air that should be at high temperature in the fixing unit 17 is suppressed, and an increase in power consumption of the entire apparatus is suppressed. can do.

Further, by providing the shielding wall 43, the air that reaches the paper outlet inner space 50 from the upstream side (right side in FIG. 1) of the shielding wall 43 is limited to the air that has passed below the shielding wall 43. At this time, the flow rate of the air passing below the shielding wall 43 is set to be smaller than the flow rate of the air sucked from the intake holes 45 by the suction of the suction fan 42. Specifically, it can be set by making the opening area of the paper discharge port 180 larger than the cross-sectional area of the gap through which the air below the shielding wall 43 passes. This makes it easier for air to pass through the paper ejection port 180 than in the space below the shielding wall 43 through which air passes, and passes through the paper ejection port 180 from the paper ejection storage unit 20 and flows into the casing 19. The generation of airflow can be promoted.

As a result, the sheet passes through the sheet discharge port 180, the sheet discharge port 180, the inside of the casing 19, the downstream guide hole 31a and the intake hole 45, the suction fan 42, and the exhaust port 53. An airflow that is discharged to the outside of the machine 100 is formed.
By sucking the air in the discharge storage unit 20 from the discharge port 180 and forming an air flow in the vicinity of the discharge port 180 in the direction opposite to the conveying direction of the paper P and exhausting the air, the inside of the discharge storage unit 20 is reduced. It is possible to cool the inside of the apparatus while preventing the high temperature air from being discharged.

FIG. 5 is an explanatory diagram of a configuration in which an exterior cover 47 is provided on a cooling mechanism 46 having an intake hole 45 and a suction fan 42 to form a cooling unit 48 having a unit structure.
As a general cooling mechanism, a duct and a fan are arranged inside the machine, but in many cases, the detachability of other units is prioritized and they are often incorporated as structural parts. Recently, good serviceability such as reduction of environmental load and decomposability and recyclability is required, and it is desired that structural parts can be easily attached and detached.

  In the configuration shown in FIG. 5, the cooling mechanism 46 is attached to the exterior cover 47 to form an integrated cooling unit 48, so that it can be easily attached to and detached from the main body of the copying machine 100. This improves serviceability (decomposability and recyclability) and assembly.

  The paper P as a recording medium includes thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, recording sheets, etc. in addition to plain paper.

  What has been described above is an example, and the following unique effects can be obtained.

(Aspect A)
Image forming means such as a charging roller 15, a photoconductor 11, a writing unit 12, a developing device 10, a transfer roller 13 and a fixing unit 17, which form an image on a recording medium such as a sheet P, and a casing 19 which houses the image forming means. And the like, a discharge port such as a discharge port 180 for discharging the recording medium on which an image is formed by the image forming means from the chassis, and a discharge storage unit 20 for storing the recording medium discharged from the discharge port. The ejected recording medium accommodating portion, which is surrounded by the wall surface portion including the wall surface portion provided with the ejection port, and which is opened at least on one side surface of the main body of the apparatus. In the image forming apparatus such as the copying machine 100, which is the space of the above, provided inside the range through which the recording medium can pass in the width direction of the conveyance path that conveys the recording medium on which the image is formed by the image forming unit to the discharge port. Further, a pre-exhaust carrier path exhausting unit such as a suction fan 42 for sucking gas such as air through a suction hole such as an intake hole 45 and discharging the gas to the outside of the housing is provided.
According to this, as described in the above embodiment, in the paper width direction of the transport path, a temperature gradient occurs such that the temperature is the highest in the vicinity of the suction hole and becomes lower as the distance from the suction hole increases. By providing the suction hole inside the range in which the recording medium can pass in the width direction of the transport path, the temperature becomes the lowest near the end of the width direction of the transport path that is farther from the suction hole. .. As a result, the distance between the highest temperature portion and the lowest temperature portion in the width direction of the transport path can be made shorter than in the configuration in which suction is performed from one end side in the width direction, and the temperature difference in the width direction caused by the temperature gradient is reduced. It becomes possible to suppress more than the conventional configuration. Therefore, in the aspect A, it is possible to suppress the temperature difference in the width direction of the conveyance path of the recording medium while suppressing the temperature rise of the discharged recording medium accommodation section.

(Aspect B)
In Aspect A, the image forming unit includes a toner image forming unit such as a charging roller 15 that forms a toner image on a recording medium such as a sheet P, a photoconductor 11, a writing unit 12, a developing device 10, and a transfer roller 13. And a fixing unit such as a fixing unit 17 that heats and fixes the toner image on the recording medium. The pre-ejection conveying path exhausting unit such as the suction fan 42 is provided between the fixing unit and the ejection port such as the sheet ejection port 180. Intake gas such as air in the carrier path.
According to this, as described in the above embodiment, before the gas heated in the fixing unit is discharged from the discharge port together with the recording medium, the gas is exhausted to the outside. Can be suppressed from being discharged to the discharged recording medium storage portion such as the discharged paper storage portion 20. As a result, it is possible to suppress the temperature rise of the ejected recording medium container.

(Aspect C)
In either mode A or B, the pre-discharge conveyance path exhaust means such as the suction fan 42 sucks gas such as air from the suction holes such as the suction holes 45 to discharge the discharge storage portion 20 or the like. The configuration is such that an airflow is formed from the recording medium storage portion through an outlet such as the sheet outlet 180 and flowing into the inside of a casing such as the casing 19.
According to this, as described in the above embodiment, an air flow in the direction opposite to the conveying direction of the recording medium such as the paper P is formed near the discharge port, and the gas whose temperature has risen is discharged from the discharge port together with the recording medium. It is possible to prevent the discharge recording medium container from being discharged. As a result, it is possible to prevent the temperature in the vicinity of the discharged recording medium accommodation portion from rising.

(Aspect D)
In either mode A or B, the space inside the casing of the casing 19 party where the image forming means is provided (the upper space 51 of the fixing unit) and the space near the discharge port such as the paper discharge port 180 ( The opening area of the discharge port is larger than the opening area of the opening (the cross-sectional area of the gap under the shielding wall 43 through which air passes) which communicates with the discharge port inner space 50).
According to this, as described in the above-described embodiment, it is possible to promote the generation of the airflow that passes through the discharge port from the discharge recording medium storage unit such as the discharge storage unit 20 and flows into the housing. As a result, in the vicinity of the discharge port, an air flow is formed in the direction opposite to the conveying direction of the recording medium such as the paper P, and the gas whose temperature has risen is discharged together with the recording medium from the discharge port to the discharged recording medium container. Therefore, it is possible to prevent the temperature in the vicinity of the discharged recording medium accommodation portion from rising.

(Aspect E)
In any one of modes A to D, the sheet P and the like on which an image is formed by an image forming unit such as the charging roller 15, the photoconductor 11, the writing unit 12, the developing device 10, the transfer roller 13, and the fixing unit 17 are used. A guide member such as a pre-ejection upper-downstream guide plate 31 for guiding the recording medium to an ejection port such as the ejection port 180 is provided, and the pre-ejection transport path exhaust means includes a downstream guide hole 31a provided in the guide member. It is provided with a suction hole and a suction device such as a suction fan 42 that sucks gas such as air in the vicinity of the suction hole and discharges it to the outside of a casing such as the casing 19.
According to this, as described in the above embodiment, it is possible to suck the high-temperature gas, which is carried by the recording medium such as the paper P or the like, toward the discharge port in the conveyance path from the suction port, and the gas whose temperature has risen. Can be prevented from being discharged together with the recording medium from the discharge port to the discharged recording medium housing portion. As a result, it is possible to prevent the temperature in the vicinity of the discharged recording medium accommodation portion from rising.

(Aspect F)
In mode E, at least one suction hole such as the downstream guide hole 31a is provided in the width direction.
According to this, as described in the above embodiment, by providing the plurality of suction holes, it is possible to suppress the occurrence of the temperature gradient in the width direction in the transport path. Even if there is only one suction hole, the same effect can be obtained by providing a long hole that is long in the width direction.

(Aspect G)
In any one of the modes E and F, at least one suction device such as the suction fan 42 is provided in the width direction.
According to this, as described in the above embodiment, by providing a plurality of suction devices, the flow path through which the gas such as air flows from the suction holes such as the downstream guide holes 31a to the suction device is not narrowed, and the exhaust gas is exhausted. It is possible to improve efficiency.

(Aspect H)
In any one of Aspects A to G, a space in the interior of a casing such as a casing 19 near a discharge port such as a discharge port 180 (paper discharge port inner space 50), a charging roller 15, a photoconductor 11, The writing unit 12, the developing device 10, the transfer roller 13 and the fixing unit 17 are provided with a shielding means such as a shielding wall 43 for shielding the space (image space above the fixing unit 51) in which the image forming means is provided.
According to this, as described in the above embodiment, it is possible to prevent the gas such as air which should be at a high temperature on the image forming unit side such as the fixing unit 17 from being cooled, and increase the power consumption of the entire apparatus. Can be suppressed. Further, by providing the shielding means, it is possible to narrow the gas flow path from the image forming means side toward the suction holes such as the downstream guide hole 31a and the intake hole 45, and to suppress the flow rate. As a result, it is possible to promote the formation of an airflow that flows from the discharged recording medium storage unit such as the discharged paper storage unit 20 through the discharge port into the inside of the casing such as the casing 19 and heads toward the suction hole. As a result, in the vicinity of the discharge port, an air flow is formed in the direction opposite to the conveying direction of the recording medium such as the paper P, and the gas whose temperature has risen is discharged together with the recording medium from the discharge port to the discharged recording medium container. Can be prevented. As a result, it is possible to prevent the temperature in the vicinity of the discharged recording medium accommodation portion from rising.

(Aspect I)
In any one of Aspects A to H, a cooling unit 48, etc., which integrally supports members constituting the pre-ejection transport path exhausting means, such as the suction fan 42, and is attachable to and detachable from the main body of the copying machine 100, etc. Equipped with an exhaust unit.
According to this, as described in the above embodiment, the disassemblability, the recyclability, and the assemblability are improved.

1 Printer Part 2 Original Reading Device 3 Original Pressing Plate 4 Paper Feed Tray 5 Paper Feeding Device 6 Movable Bottom Plate 7 Paper Feeding Roller 8 Friction Pad 9 Registration Roller Pair 10 Developing Device 11 Photoreceptor 12 Writing Unit 13 Transfer Roller 14 Toner Bottle 15 Charging roller 16 Thermal fixing roller pair 17 Fixing unit 18 Paper discharging roller pair 19 Casing 20 Paper discharging storage section 21 Paper discharging tray 22 Manual feeding tray 24 Calling roller 26 Inversion path switching claw 27 Double-sided feeding roller pair 29 Supporting pillar 30 Upper front of paper discharging Upstream-side guide plate 30a Upstream-side guide hole 31 Upstream-upper upstream downstream-side guide plate 31a Downstream-side guide hole 32 Down-stream-before lower guide plate 42 Suction fan 43 Shielding wall 45 Intake hole 46 Cooling mechanism 47 Exterior cover 48 Cooling unit 50 Discharge Space inside the paper port 51 Space above the fixing unit 52 Exhaust duct 53 Exhaust port 100 Copier 180 Paper exit 190 Duct bottom plate P Paper

Patent No. 4760602

Claims (6)

A conveyance path for guiding the recording medium,
An image forming means for forming an image on the recording medium,
A housing that houses the image forming unit,
In an image forming apparatus including a discharge port for discharging the recording medium from the housing,
A space inside the housing, which is a discharge port inner space including at least a part of the transport path and the discharge port;
An opening for inserting the recording medium into the space inside the outlet,
An exhaust passage that guides the gas in the exhaust port inner space to the outside of the housing from a suction hole provided at a position different from the exhaust port,
An exhaust means provided in the exhaust path for exhausting the gas to the outside of the housing;
The suction hole is provided at a position facing the transport path in the discharge port inner space,
A heating unit that heats the recording medium is provided on the upstream side of the opening in the transport direction of the recording medium,
An image forming apparatus, wherein both the gas having passed through the opening and the gas having passed through the outlet flow into the inner space of the outlet when the exhaust unit performs an exhaust operation. The image forming apparatus according to claim 1,
The suction hole is provided vertically above the transport path,
The exhaust passage is an arrangement that extends from the suction hole toward the upstream side in the transport direction of the recording medium,
The image forming apparatus is characterized in that the exhaust unit is provided at a position apart from the suction hole in the exhaust path. The image forming apparatus according to claim 1,
An image forming apparatus, wherein an opening area of the discharge port is larger than an opening area of the opening. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus, wherein a height at which the opening is provided in a vertical direction is equal to or lower than a height at which the discharge port is provided. The image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus is characterized in that the exhaust unit is arranged to exhaust the gas in a direction from the suction hole toward an upstream side in a transport direction of the recording medium. The image forming apparatus according to any one of claims 1 to 5,
The image forming apparatus, wherein the exhaust unit exhausts the gas downward .

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