JP2019086612A - Image forming apparatus and heat-blocking components used for the same - Google Patents

Abstract

To inhibit an increase in temperature of an environmental space on the periphery of a fixing unit of a heating system to prevent heat from the fixing unit from unnecessarily flowing out to an image forming unit and a transfer unit.SOLUTION: An image forming apparatus comprises a fixing unit 4 that is located lateral to an image forming unit 2 and above a transfer unit 3 in an apparatus housing 1, and prevents, with heat-blocking components 5, heat from the fixing unit 4 from flowing out to a space on a side of the image forming unit 2 located above the transfer unit 3. The image forming apparatus includes, as the heat-blocking components 5, a vertical direction partition part 6 that extends in the vertical direction to be a partition between the image forming unit 2 and fixing unit 4 located above the transfer unit 3, a lateral direction partition part 7 that is provided near a lower part of the vertical direction partition part 6 and projects toward the lateral direction to be a partition between the fixing unit 4 and transfer unit 3 without blocking a conveyance path of a recording medium S, an air supply unit 8 that supplies cooling air from the space on a side of the image forming unit 2 to a space on a side of the fixing unit 4, and an exhaust unit 9 that exhausts heated air from the space on a side of the fixing unit 4 to a space in the space on a side of the image forming unit 2 other than the image forming unit 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus and a heat shielding component used for the same.

Conventionally, as an image forming apparatus of this type, for example, those described in Patent Documents 1 and 2 are already known.
In Patent Document 1, a plate extends from the vicinity of an air inlet toward a space sandwiched between a fixing device and an image forming unit, and this space is divided into upper and lower parts in the vertical direction, and Among the gaps between the image forming unit and the image forming unit, it is a mode having a shape that reduces the gap closer to the front side than the back side, whereby air on the back side is more than the front side when air is drawn. An image forming apparatus is disclosed in which the amount of heat removed on the back side is larger than that on the front side by sucking out the ink.
In Patent Document 2, a heat shielding device is provided between the fixing device of the image forming apparatus and the image forming unit, and the heat shielding between the fixing device and the image forming unit is performed, and the heat shielding device, the image forming unit and the toner cleaning The air flow path is formed by the device, and the air flow can be circulated by the fan in the air flow path. The heat shield has an opening opening toward the fixing device, serves as a duct for the cooling air flow to the fixing device, and an open / close cover An image forming apparatus is disclosed in which the opening and the duct inlet are opened with the opening operation, and the opening and the inlet of the duct are closed when the openable cover is closed.

JP, 2013-195809, A (Embodiment for carrying out the invention, FIG. 8) JP, 2014-006435, A (Embodiment for carrying out the invention, FIG. 1)

  The technical problem to be solved by the present invention is to suppress the temperature rise of the environmental space around the fixing unit of the heating method and to suppress the unnecessary flow of heat from the fixing unit to the image forming unit and the transfer unit. It is in.

  According to a first aspect of the present invention, there is provided an image forming unit provided in an apparatus housing and forming an image using an image forming material capable of being heated and fixed, and provided on a side of the image forming section in the apparatus housing. A transfer unit for transferring an image formed by the image forming unit onto a recording medium, and a side of the image forming unit and above the transfer unit in the apparatus housing, and the transfer unit A fixing unit that heats and fixes at least the image transferred to the recording medium, and the image forming unit located above the transfer unit in the apparatus casing is provided to partition the fixing unit. And a heat shielding component for blocking the flow of heat from the fixing unit to the image forming unit side space, wherein the heat shielding component is provided with the image forming unit and the fixing unit located above the transfer unit. A longitudinal partition extending longitudinally so as to partition between the A horizontal partition provided in the vicinity and projecting in the horizontal direction that divides the fixing unit and the transfer unit so as not to block the conveyance path of the recording medium; and the vertical partition provided in the vertical direction An air supply unit for supplying cooling air from the image forming unit side space in the casing to the fixing unit side space, and heating provided from the fixing unit side space in the apparatus casing, provided in the longitudinal direction partition portion And an exhaust unit for discharging air toward a space other than the imaging unit in the imaging unit side space.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the longitudinally dividing portions are opposed frame members of the device housing positioned on both sides in the width direction intersecting the conveyance direction of the recording medium. It is an image forming apparatus characterized in that it is bridged between.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the horizontal direction partition portion is bridged between opposing frame members of the device housing positioned on both sides in the width direction of the recording medium. An image forming apparatus characterized in that
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, in the horizontal partition, the end regions located on both sides in the width direction of the recording medium are compared to the middle region. According to another aspect of the present invention, there is provided an image forming apparatus, wherein a dimension of protrusion from the vertical direction partition portion is set long.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, of the lateral partition parts, a long end area with a projecting dimension and an intermediate area with a short projecting dimension positioned on both sides in the width direction of the recording medium. Is an image forming apparatus characterized by being connected via a curved portion.
A sixth aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the lateral partition portion has a hemming bending portion at the tip end portion facing the conveyance path of the recording medium. Image forming apparatus characterized in that
The invention according to claim 7 is characterized in that, in the image forming apparatus according to any one of claims 1 to 6, the exhaust unit is disposed to be biased toward the back side of the apparatus casing than the air supply unit. An image forming apparatus.
The invention according to claim 8 is an image forming apparatus according to claim 7, wherein the exhaust unit is disposed below the air supply unit.
According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, at least a part of the drive transmission mechanism for drivingly transmitting the driving force to the fixing portion is installed in the vertical direction partition portion. It is an image forming apparatus characterized by having an opening.
According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, the vertical direction partition portion contains an imaging material container in which an imaging material is accommodated as a part of the imaging portion. The image forming apparatus is characterized in that it is partitioned between the fixing unit and the fixing unit.

  According to an eleventh aspect of the present invention, there is provided an image forming section provided in an apparatus housing and forming an image using an image forming material which can be heat-fixed, and provided on a side of the image forming section in the apparatus housing. A transfer unit for transferring an image formed by the image forming unit onto a recording medium, and a side of the image forming unit and above the transfer unit in the apparatus housing, and the transfer unit And a fixing unit for heating and fixing an image transferred to a recording medium, the image forming unit and the fixing unit positioned above the transfer unit in the apparatus housing. A heat shielding component that is provided to divide the space between the image forming unit and the image forming unit side space, and the image forming unit and the image forming unit positioned above the transfer unit. A longitudinal partition portion extending in the longitudinal direction so as to partition between the fixing portion and the longitudinal portion; A horizontal direction partition part provided near the lower part of the facing partition part and protruding in the horizontal direction that divides the fixing part and the transfer part so as not to obstruct the conveyance path of the recording medium, and the vertical direction partition part Provided in an air supply unit for supplying cooling air from the image forming unit side space in the apparatus casing to the fixing unit side space, and provided in the longitudinal partition section, the fixing unit in the apparatus casing And an exhaust unit that discharges the heated air from the side space toward the space other than the imaging unit in the imaging unit side space.

According to the first aspect of the present invention, it is possible to suppress the temperature rise of the environmental space around the fixing unit of the heating method, and to suppress the unnecessary flow of heat from the fixing unit to the image forming unit and the transfer unit. .
According to the second aspect of the present invention, the overall rigidity of the device casing can be enhanced by utilizing the heat shielding component as a beam member.
According to the third aspect of the present invention, it is possible to increase the overall rigidity of the device casing as compared to the aspect in which only the longitudinal partition portion is bridged between the opposing frame members of the device casing.
According to the fourth aspect of the present invention, the heat flowing from the peripheral area around the fixing section to the transfer section through the vicinity of the width direction of the recording medium is greater than the horizontal partition section whose projection dimension from the vertical partition section is uniform. It can be prevented.
According to the fifth aspect of the present invention, the heat shielding effect from the space around the fixing portion to the transfer portion is enhanced compared to the aspect in which the end region and the intermediate region of the horizontal partition portion are continuous through the corner portion. it can.
According to the sixth aspect of the present invention, even if the recording medium from the transfer part to the fixing part comes in contact with the lateral partition part, the recording medium can be prevented from being damaged.
According to the invention of claim 7, the air supplied from the air supply unit and the exhaust gas reaching the exhaust unit can be flowed without stagnation in the space on the fixing unit side, and the air is exhausted toward the back side of the apparatus casing. It is easy to do.
According to the eighth aspect of the present invention, it is effective to exhaust the heated air from the fixing unit in the fixing unit side space without staying upward.
According to the invention of claim 9, even when the heat shield component is incorporated, the drive transmission mechanism can be installed in the vicinity of the fixing portion without interfering with the heat shield component.
According to the tenth aspect of the present invention, it is possible to suppress a situation in which the heat from the fixing unit is unnecessarily discharged to the imaging material container and the transfer unit.
According to the invention of claim 11, it is possible to suppress the temperature rise of the environmental space around the fixing unit of the heating method, and to suppress the unnecessary flow of heat from the fixing unit to the image forming unit and the transfer unit. The present invention can provide a heat shield part used in an image forming apparatus.

(A) is explanatory drawing which shows the outline | summary of embodiment which integrated the heat shielding component to which this invention was applied, (b) is the cross-sectional explanatory drawing cut | disconnected by the BB line in (a). FIG. 1 is an explanatory view showing an entire configuration of an image forming apparatus according to Embodiment 1; FIG. 6 is an explanatory view showing a peripheral structure of a sheet conveyance path around a fixing device used in Embodiment 1. FIG. 6 is an explanatory view showing an air supply and exhaust structure around the fixing device used in the first embodiment. 5 is an explanatory view showing a heat shield structure provided around the fixing device used in Embodiment 1. FIG. FIG. 2 is an explanatory view showing a heat shield component used in the first embodiment. (A) is a plan explanatory view of the lateral partition member of the heat shield component, (b) is a cross-sectional view taken along the line B-B in (a), and (c) is an installation of a drive transmission mechanism of the fixing device near the heat shield component. It is explanatory drawing which shows an example. FIG. 6 is an explanatory view showing the main parts of the exhaust part of the heat shield component used in the first embodiment. It is explanatory drawing which shows the principal part of the exhaust_gas | exhaustion part which removed the heat-insulation components in FIG. FIG. 6 is an explanatory view showing an air supply path leading to the heat shield component used in the first embodiment. FIG. 6 is an explanatory view showing an air supply path from the air supply unit of the heat shield component used in the first embodiment. FIG. 6 is an explanatory view schematically showing an air supply and exhaust operation around the fixing device of the image forming apparatus according to Embodiment 1. (A) is explanatory drawing which shows the heat-insulation components of the image forming apparatus which concerns on the form 1 of a comparison, (b) is explanatory drawing which shows the atmospheric temperature above the process cartridge by the presence or absence of heat-insulation components.

Outline of Embodiment FIG. 1 (a) shows an outline of an embodiment of an image forming apparatus incorporating a heat shielding component to which the present invention is applied, and FIG. 1 (b) is a line B-B in FIG. It is cross-sectional explanatory drawing cut | disconnected by this.
In FIG. 1, an image forming apparatus is provided in an apparatus housing 1 and forms an image using an image forming material which can be heat-fixed, and an image forming part 2 of the apparatus housing 1. A transfer unit 3 provided laterally and transferring the image formed by the image forming unit 2 onto the recording medium S, and on the side of the image formation unit 2 and above the transfer unit 3 in the apparatus housing 1 A fixing unit 4 is provided, which heats and fixes at least the image transferred onto the recording medium S by the transfer unit 3, and an image forming unit 2 and a fixing unit 4 located above the transfer unit 3 in the apparatus housing 1. And a heat shielding component 5 that blocks the heat from the fixing unit 4 from flowing out to the space on the imaging unit 2 side, and the heat shielding component 5 is configured as shown in FIG. As shown in b), a longitudinal partition 6 extending longitudinally to partition between the image forming unit 2 and the fixing unit 4 located above the transfer unit 3; A transverse partition 7 provided in the vicinity of the lower part of the partition 6 and projecting in the lateral direction, which partitions the fixing unit 4 and the transfer unit 3 so as not to obstruct the conveyance path of the recording medium S, and a longitudinal partition 6 provided in the vertical direction partition portion 6 for supplying cooling air from the image forming portion 2 side space in the device housing 1 to the fixing portion 4 side space, and the device housing 1 And an exhaust unit 9 for discharging the heated air from the space on the fixing unit 4 side in the space on the image forming unit 2 side toward the space other than the image forming unit 2.

In such a technical means, the heat shield component 5 is not limited to one which is bridged to the opposing frame members of the device casing 1 but also includes one fixed to only one side of the frame member.
Moreover, although what is integrally shape | molded by the vertical direction partition part 6 and the horizontal direction partition part 7 is common, the aspect which fixes a separate thing with a fixing tool is also included.
Furthermore, the longitudinal partition 6 widely includes one extending in the longitudinal direction within a range that fits in the space between the image forming unit 2 located above the transfer unit 3 and the fixing unit 4 and is not limited to the vertical direction. And may be inclined with respect to the vertical direction. Here, as the image forming unit 2 located above the transfer unit 3, for example, in an intermediate transfer type image forming apparatus, an image forming element located above the intermediate transfer member 2 b (for example, an image forming material container) 2c and an image forming unit including the image carrier 2a). The embodiment shown in FIG. 1 is an example in which the image carrier 2a is disposed below the intermediate transfer member 2b.

In addition, the horizontal partition 7 widely includes one extending in the lateral direction that divides the fixing unit 4 and the transfer unit 3 at a location that does not block the conveyance path of the recording medium S, and is not limited to the horizontal direction. It may be
Furthermore, the air supply unit 8 only needs to have at least an air supply opening, and an air intake fan may be installed around the air supply opening, and other than the longitudinal direction partition 6 (for example, in the middle of the duct) You may install a fan.
Furthermore, the exhaust part 9 may have at least an exhaust opening, and a fan may be installed around the exhaust opening, or even if the fan is installed other than the longitudinal partition 6 (for example, in the middle of the duct) Good.

Next, a representative aspect or a preferable aspect of the image forming apparatus according to the present embodiment will be described.
First, as an example of installation of the longitudinal partition portion 6 in the apparatus casing 1, as shown in FIGS. 1 (a) and 1 (b), the apparatus casing positioned on both sides in the width direction intersecting the conveyance direction of the recording medium S A mode in which the frame members 1f and 1r facing each other are bridged may be mentioned. The present embodiment is an aspect in which the heat shield component 5 is used as a beam member, and the bridged end portions of the vertical direction partition portion 6 are fixed to the frame members 1 f and 1 r by screws and welding.
In addition, as an example of installation of the horizontal partition 7 in the device case 1, as shown in FIGS. 1 (a) and 1 (b), the device cases 1 located on both sides in the width direction of the recording medium S face each other. An embodiment in which the frame members 1f and 1r are bridged may be mentioned. In this embodiment, in addition to the vertical partition 6, the horizontal partition 7 is also used as a beam member, and the same fixing method as the vertical partition 6 is adopted.

Furthermore, as a preferable embodiment of the transverse partition 7, an embodiment in which the end area located on both sides in the width direction of the recording medium S has a projection dimension from the longitudinal partition 6 set longer than that of the middle part . In this embodiment, the overall rigidity of the device housing 1 can be enhanced as compared with the horizontal partition 7 in which the projection dimension from the vertical partition 6 is uniform. For this reason, the beam effect on the frame members 1 f and 1 r is enhanced by increasing the contact area between the opposing frame members 1 f and 1 r of the device housing 1 and the both ends of the lateral partition 7.
Furthermore, as another preferable mode of the transverse partition 7, the long end area of the projecting dimension positioned on both sides in the width direction of the recording medium S in the transverse partition 7 and the intermediate area having a short projecting dimension There is a mode in which connection is made via the curved portion. This example is an aspect in which the end area and the intermediate area having different projecting dimensions of the horizontal partition 7 are connected via a curved portion, and the cross-sectional area of the conveyance path of the recording medium S due to the presence of the curved portion. The effect of reducing the
Moreover, as another preferable aspect of the horizontal direction partition part 7, the aspect in which the front-end | tip part facing the conveyance path of the recording medium S has a hemming bending part is mentioned. The present embodiment is an aspect in which the structure of the tip portion is devised in consideration of the possibility of the tip portion facing the transport path of the recording medium S in the horizontal partition 7 coming into contact with the recording medium S.

In addition, as an example of the layout of the exhaust unit 9 and the air supply unit 8, an aspect in which the exhaust unit 9 is disposed closer to the rear side of the device casing 1 than the air supply unit 8 may be mentioned. In this embodiment, the exhaust unit 9 is disposed on the back side of the apparatus housing 1 and the air supply unit 8 is disposed on the front side of the exhaust unit 9. In the present embodiment, the operating side of the image forming apparatus is the front side of the apparatus housing 1, and the opposite side of the front side of the apparatus housing 1 is the rear side of the apparatus housing 1.
Furthermore, as a preferable aspect of the exhaust part 9 and the air supply part 8, the aspect by which the exhaust part 9 is arrange | positioned downward rather than the air supply part 8 is mentioned. This aspect is effective in exhausting the heated air from the fixing unit 4 without staying upward in the space on the fixing unit 4 side.

Further, as a preferable aspect of the longitudinal direction partition part 6, an aspect having an opening in which at least a part of a drive transmission mechanism for transmitting a driving force to the fixing part 4 is provided. In this example, when installing the drive transmission mechanism in the vicinity of the fixing unit 4, the longitudinal partition unit may be provided without securing a space for installation of the drive transmission mechanism between the fixing unit 4 and the longitudinal partition unit 6. This is an aspect in which the drive transmission mechanism can be installed using the opening 6.
Furthermore, as another preferable mode of the longitudinal direction partition section 6, an aspect in which the image forming material storage container 2c containing an image forming material as a part of the image forming section 2 is partitioned between the image forming material container 2 and the fixing section 4 can be mentioned. In this example, the fixing unit 4 and the imaging material container 2c are partitioned by the vertical partition 6, so that heat from the fixing unit 4 is prevented from affecting the imaging material container 2c. It is valid.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the attached drawings.
実 施 Embodiment 1
FIG. 2 shows the entire configuration of the image forming apparatus according to the first embodiment.
-Overall configuration of image forming apparatus-
In the figure, the image forming apparatus 20 is configured as a full color image forming apparatus adopting, for example, an electrophotographic method, and in this example, a glass etc. is formed on the top of the apparatus casing 21 in which the imaging unit 25 is built. The original 22 transported by the automatic document feeder 23 and the automatic document feeder 23 for automatically feeding a document (not shown) to a predetermined reading position on the platen 22 is provided. This embodiment is provided with an image reading device 24 for reading an unshown original placed on the image reader 22. Of course, the image forming apparatus 20 may not include the automatic document feeder 23 or the image reader 24.

-Imaging unit-
In the present embodiment, the image forming unit 25 in the apparatus casing 21 adopts an intermediate transfer method, and for example, a plurality of color components arranged in a substantially horizontal direction (in this example, yellow (Y), magenta (M), cyan (C), black (K) image forming portion 30 (specifically, 30a to 30d) capable of forming an image, and recording medium formed with each image forming portion 30 For example, before being transferred onto the sheet S, the transfer sheet is temporarily transferred to and held on a belt-like intermediate transfer member 40, for example.
In this example, each of the image forming units 30 (30a to 30d) has a photosensitive member 31 as an image carrier, and a charging device 32 for charging the photosensitive member 31 around the photosensitive member 31 is charged. An exposure device 33 such as an LED writing device for writing an electrostatic latent image on the photosensitive member 31 and a developer containing at least a toner as charged image forming particles on the electrostatic latent image formed on the photosensitive member 31 A developing device 34 for visualizing the image, and a primary transfer device 35 provided on the back side of the intermediate transfer member 40 facing the photosensitive member 31 and transferring the developed image formed on the photosensitive member 31 to the intermediate transfer member 40 side. And a cleaning device 36 for cleaning residual toner and the like remaining on the photosensitive member 31.

The intermediate transfer member 40 is formed of, for example, a belt-like member, and is disposed above each of the image forming units 30 (30a to 30d) in this example, and is looped around a plurality of tension rolls 41 to 44 It has become. And in this example, the tension roll 41 is used as a drive roll, and the tension rolls 42 to 44 are used as driven rolls. Among the driven rolls, the tension roll 42 is also configured to share one element of a secondary transfer device 50 as a transfer unit described later, and the tension roll 43 applies tension to the intermediate transfer member 40. The tension roll 44 is used as an exposing roll that forms an image forming surface of the intermediate transfer member 40 with respect to the photosensitive member 31. An intermediate transfer member cleaning device 45 for cleaning residual toner and the like on the intermediate transfer member 40 is provided at, for example, a portion of the intermediate transfer member 40 facing the tension roll 41.
Furthermore, in the present embodiment, a plurality of developer cartridges 38 (specifically, developer storage containers for storing developers (image forming materials) containing at least respective color component toners above the intermediate transfer member 40 (specific Specifically, 38a to 38d) are installed side by side in the substantially horizontal direction. Below each developer cartridge 38, a developer conveying device 39 connected to the developing device 34 of each image forming unit 30 is provided, and the corresponding developing device 34 is provided via the developer conveying device 39. The developer is supplied.

-Secondary transfer device-
In the present embodiment, as shown in FIG. 2 and FIG. 3, a secondary transfer device 50 is provided as a transfer portion for transferring the image by the toner on the intermediate transfer member 40 onto the sheet S. In the secondary transfer device 50, the transfer roll 51 is disposed in contact with a portion of the intermediate transfer member 40 corresponding to the tension roll 42, and the tension roll 42 facing the transfer roll 51 functions as an electrode roll. The transfer voltage necessary for image transfer is applied between the intermediate transfer member 40 and the sheet S by applying a transfer voltage between the transfer roller 42 and the tension roll 42.

-Fixing device-
In the present embodiment, as shown in FIGS. 2 and 3, a fixing device 60 as a fixing unit is installed at a position approximately immediately above the secondary transfer device 50.
In this example, the fixing device 60 includes a heating fixing roll 61 that fixes the sheet S by heating an image with unfixed toner, and an endless belt-shaped pressure fixing belt 62 that presses the sheet S against the heating fixing roll 61. A pressing pad 63 for pressing the heat fixing roll 61 from the inner periphery of the pressure fixing belt 62, and a heater 64 such as a halogen lamp disposed in the heat fixing roll 61 to heat the heat fixing roll 61; By holding and conveying the sheet S in the contact area between the heating and fixing roll 61 and the pressure fixing belt 62, the unfixed toner image is heated, pressed and fixed on the sheet S. The fixing device 60 is not necessarily limited to the heating and pressure fixing method, and any method such as a non-contact heating method and a laser light fixing method may be selected as long as at least a heating step is involved.

-Curl correction device-
In the present embodiment, as shown in FIG. 2 and FIG. 3, the curl correcting device 70 is installed at a position approximately immediately above the fixing device 60.
In this example, the curl correction device 70 is disposed on the fixed image side of the sheet S, and has a curl correction belt 71 formed in an endless belt shape, and a curl correction roll disposed on the non-image side of the sheet S. And a pressing pad 73 for pressing the curl correcting belt 71 from the inner periphery thereof toward the curl correcting roll 72.
In this example, the contact area between the curl correction belt 71 and the curl correction roll 72 functions as a curl correction unit for correcting the curl of the sheet S.
Here, in the curl correction device 70 of this example, the positional relationship between the curl correction belt 71 and the curl correction roll 72 is a belt shape with respect to the positional relationship between the heat fixing roller 61 and the pressure fixing belt 62 of the fixing device 60. It arrange | positions so that the positional relationship of a member and a roll-shaped member may become reverse.
By configuring the curl correction device 70 as described above, the curl correction is performed as follows.
That is, when the sheet S holding the unfixed toner image passes the fixing device 60 (the heating fixing roller 61 and the pressure fixing belt 62), the sheet S is deformed in a concave shape toward the heating fixing roll 61 (this embodiment) Then, this is called "upper curl". On the other hand, when the fixed paper S passes through the curl correction device 70 (the curl correction belt 71, the curl correction roll 72), the curl tendency (in this example, the sheet S is deformed into a concave shape toward the curl correction roll 72). It is called "down curl". Therefore, the upper curl of the sheet S generated by the fixing device 60 is offset by the down curl of the sheet S generated by the curl correction device 70, and the curl generated on the sheet S is corrected.
In the present embodiment, although the aspect provided with the curl correction device 70 is shown, it is a matter of course that the present invention can be applied to an aspect without the curl correction device 70.

-Paper transport system-
In the present embodiment, the sheet conveyance system 80 has a plurality of sheet supply devices 81 and 82 below the apparatus casing 21 and the sheet S supplied from any of the sheet supply devices 81 and 82 is substantially vertical. The sheet is conveyed upward from below by the conveyance roll 84 appropriately installed along the vertical conveyance path 83 extending to the side, and is aligned by the alignment roll 85 in front of the secondary transfer device 50 and then passes through the secondary transfer device 50 After the fixing, the fixing device 60 and the curling correction device 70 are allowed to pass, and the first sheet storage portion 91 provided at the upper portion of the apparatus casing 21 or the second provided at the side of the apparatus casing 21. The curled sheet S is conveyed to the sheet storage unit 92.
In this example, the sheet conveyance system 80 is branched from the return conveyance path 93 provided detouring to the vertical conveyance path 83 in addition to the vertical conveyance path 83 and the middle of the vertical conveyance path 83. And a horizontal transport path 95 extending substantially horizontally in the space above the developer cartridge 38.

Here, a first sheet storage section 91 is provided at the end position of the vertical conveyance path 83, and a discharge roll 86 capable of rotating in the forward and reverse directions is provided immediately before the first sheet storage section 91. Further, a switching gate 87 for path switching is provided at a branch position between the vertical conveyance path 83 and the horizontal conveyance path 95, and switching of the path between the vertical conveyance path 83 and the return conveyance path 93 is also performed. A gate 88 is provided, and the switching gate 88 reverses the discharge roll 86 while maintaining the state where the single-sided image-forming sheet S is nipped by the vertical conveyance path 83 and makes the return conveyance path 93 A first switching operation for pulling in and a second switching operation for returning the sheet S having one-sided image formation through the vertical conveyance path 83 as it is and pulling it into the conveyance path 93 are performed.
Further, a plurality of transport rolls 94 are installed in the return transport path 93, and a plurality of transport rolls 96 are installed in the horizontal transport path 95. The second sheet storage portion 92 is disposed at the end position of the horizontal transport path 95. The discharge roller 97 is provided immediately in front of the second sheet storage unit 92.
Therefore, in the present embodiment, in the double-sided imaging mode, the sheet S on which single-sided image formation has been performed through the vertical conveyance path 83 is reversed again to the front of the alignment roll 85 of the vertical conveyance path 83 via the return conveyance path 93. After that, the sheet S is conveyed along the vertical conveyance path 83 so as to form an image on the other side of the sheet S. When it is desired to store the sheet S in the second sheet storage unit 92, the sheet S on which single-sided or double-sided image formation has been performed is switched to the horizontal conveyance path 95 in the middle of the vertical conveyance path 83 and conveyed. Good.

-Heat shield parts-
In the present embodiment, the heat shield component 100 is installed in the apparatus housing 21. The heat shield 100 is, as shown in FIGS. 2 and 3, an imaging unit 25 (specifically, a developer cartridge 38 (38 a) of the apparatus casing 21 located above the secondary transfer device 50. .About.38d)) and the fixing device 60 and the curl correcting device 70 are provided.
<Basic configuration of heat shield parts>
In the present embodiment, the heat shield component 100 is integrally formed of, for example, a stainless steel material having a low thermal conductivity, and the imaging unit 25 (in the present embodiment, the developer cartridge) located above the secondary transfer device 50 A vertical partition plate 101 extending in the vertical direction (corresponding to a substantially vertical direction in this example) so as to partition between the fixing device 60 and the curl correction device 70; In the vicinity of the lower portion of the plate 101, a lateral direction which protrudes in a lateral direction (corresponding to a substantially horizontal direction in this example) that divides the fixing device 60 and the secondary transfer device 50 so as not to obstruct the vertical transport path 83. The partition plate 110 is integrally formed.

<Configuration example of vertical direction partition plate>
In the present embodiment, as shown in FIGS. 3, 5 and 6, the longitudinal partition plate 101 is formed of a substantially rectangular plate material extending in the width direction intersecting the sheet conveyance direction, and the width direction of the sheet It is bridged between the frame members 21f and 21r of the device housing 21 located on both sides. Here, when the width direction of the sheet is the front side of the side where the image forming apparatus 20 is operated, this corresponds to the front-rear direction of the apparatus case 21, and the frame member 21 f is positioned on the front side of the apparatus case 21. The frame member 21 r is located on the back side of the device case 21.
In this example, the stretched end portion of the longitudinal direction partition plate 101 is fixed to the frame members 21f and 21r by screwing or welding. In addition, a positioning protrusion 102 is appropriately provided at one end of the vertical direction partition plate 101, and a positioning hole (not shown) into which the positioning protrusion 102 can be inserted in the frame member 21f of the corresponding device case 21 Not shown). Further, a substantially rectangular cutout opening 103 is formed in a portion of the vertical direction partition plate 101 facing the frame member 21 r located on the back side of the device housing 21. As shown in FIG. 5 and FIG. 7C, the notch opening 103 has a drive transmission mechanism (a drive gear train, a drive transmission belt, etc.) 65 for transmitting a driving force to, for example, the heating fixing roll 61 of the fixing device 60. At least a part is to be installed. Furthermore, a reinforcing flange 104 (see FIG. 6) bent at approximately 90 degrees is integrally formed on the upper edge portion of the vertical direction partition plate 101.

<Configuration example of horizontal direction partition plate>
Further, as shown in FIGS. 3, 5 and 6, the transverse partition plate 110 is formed by bending the vicinity of the lower portion of the longitudinal partition plate 101 by about 90 degrees and integrally molding the same. The projecting dimension is set smaller than the dimension in the vertical direction of the longitudinal partition plate 101, and is spanned by the frame members 21f and 21r of the apparatus casing 21 positioned on both sides in the width direction of the sheet.
In this example, the bridged end of the lateral partition plate 110 is fixed to the frame members 21f and 21r by screwing or welding. In addition, a positioning projection 112 is appropriately provided at one end of the transverse partition plate 110, and a positioning hole (the positioning projection 112 can be inserted into the corresponding frame member 21f of the apparatus housing 21) Not shown). Further, a mounting flange 113 bent at approximately 90 degrees is integrally formed at the other end of the transverse partition plate 110, and in this example, it is abutted against the frame member 21r and fixed by a screw 114. It has become.

In particular, in the present embodiment, as shown in FIGS. 6 and 7A, in the lateral direction partition plate 110, the end area located on both sides in the width direction of the sheet S is Re, and the intermediate area is Rc. Assuming that the projecting dimensions of the respective regions Re and Rc from the longitudinal direction partition plate 101 are he and hc, the relationship of he> hc is satisfied. Here, the projecting dimension he of the end region Re of the transverse partition plate 110 may be the same at both ends or may be different from each other.
Further, in the present example, in the lateral partition plate 110, the end region Re and the middle region Rc are connected via the curved portion 115, and the protruding end side of the end region Re is also formed in the curved portion 116. It is done.
Furthermore, in the present embodiment, as shown in FIGS. 7A and 7B, the transverse partition plate 110 has a tip end facing the transport path of the sheet S (corresponding to the vertical transport path 83 in FIG. 2). The hemming bending portion 117 is formed by bending around 180 degrees. The hemming bending portion 117 is to prevent the sheet S from being damaged even if the leading end of the lateral direction partition plate 110 contacts the sheet S.
Furthermore, a plurality of vent holes 118 are opened in the middle region Rc of the transverse partition plate 110, and the vent holes 118 create an air flow from the vicinity of the developer cartridge 38 to form a layer of air, thereby fixing It is provided to reduce the thermal effect of the developer cartridge 38 on the developer cartridge 38.

<Air supply structure>
In the present embodiment, the heat shield component 100 includes an air supply unit that supplies cooling air from the space on the image forming unit 25 side in the apparatus housing 21 to the space on the fixing device 60 side.
In this example, as shown in FIGS. 5 and 6, a plurality of (two in this example) rectangular air supply openings 130 are opened as an air supply portion in the upper half region of the vertical direction partition plate 101. .
And while the ventilation fan 131 is inserted and attached to each air supply opening 130, the air supply channel | path by the air supply duct 132 (refer FIG. 4) is connected.
In this example, the air supply duct 132 secures an air supply passage 133 between the developer cartridge 38 (38a to 38d) and the horizontal conveyance path 95, as shown in FIGS. 4, 5, 10 and 11. The air outside the device case 21 can be supplied from the side of the device case 21. Here, the air supply duct 132 forms an air supply passage 133 between the lower dividing member 135 which divides between the developer cartridge 38 and the upper dividing member 136 which divides between the horizontal conveyance path 95. It is In this example, one end 135a of the lower partition member 135 is connected to the lower end of the blower fan 131, and the one end 135a is curved along the outer shape of the black (K) developer cartridge 38d. A curved portion 135b and a flat portion 135c disposed substantially horizontally above the developer cartridges 38 (38a to 38d) via the curved portion 135b are provided. Further, the upper partition member 136 doubles as the lower guide chute 98 a of the pair of guide chutes 98 (specifically, 98 a and 98 b) for guiding the horizontal conveyance path 95. The upper guide chute 98b is formed with a slit-like vent hole 99 for discharging the heat of the sheet S conveyed to the horizontal conveyance path 95 to the outside.

  Further, in the present embodiment, the air supply opening 130 (see FIG. 5) of the heat shield component 100 is provided at a portion substantially facing the curl correction device 70 as shown in FIG. 3 and FIG. In the present embodiment, the curl correction device 70 has a pair of guide plates 75 and 76 for guiding the air flow from the blower fan 131 in the circumferential direction of the curl correction belt 71. The guide plates 75 and 76 are disposed on the upper and lower sides of the curl correction belt 71, and are provided with an air supply port 77 on the side of the blower fan 131 and are arranged to cover the outer periphery of the curl correction belt 71 over approximately a half circumference.

<Exhaust structure>
Further, in the present embodiment, the heat shield component 100 discharges the heated air from the space on the fixing device 60 side in the apparatus housing 21 toward the space other than the imaging section 25 in the space on the imaging section 25 side. It has an exhaust part.
In this example, as shown in FIG. 6, FIG. 8 and FIG. 9, an exhaust opening 150 consisting of, for example, a large number of through holes is provided in the lower half of the longitudinal partition 101 near the back of the device case 21. An exhaust passage 152 connected by an exhaust duct 151 is connected to the exhaust opening 150.
In the present embodiment, the exhaust duct 151 is provided in the space on the image forming portion 25 side of the vertical direction partition plate 101 of the heat shield component 100, and the first exhaust duct 152 is provided to secure the exhaust passage 152 between the vertical direction partition plate 101. A duct member 153 and a first space member provided adjacent to the first duct member 153 and having a connection port 155 on the side of the first duct member 153 and extending toward the back side of the apparatus casing 21 And the second duct member 154. An exhaust fan 156 is provided near the end position of the second duct member 154, and a ventilation outlet 157 communicating with the outside of the apparatus casing 21 is provided at the end of the second duct member 154. The air is exhausted from the outlet 157. A filter member (not shown) is provided in the vicinity of the ventilation outlet 157 of the exhaust duct 151 so as to capture toner, dust and the like contained in the exhausted air.

-Operation of the image forming apparatus-
Next, the operation of the image forming apparatus according to the present embodiment will be described.
In the present embodiment, an image of each color component toner formed in each of the image forming units 30 (30a to 30d) is primarily transferred from the photosensitive member 31 to the intermediate transfer member 40 and conveyed along the vertical conveyance path 83. After being secondarily transferred to the sheet S by the secondary transfer device 50, the sheet S to which the image has been transferred is subjected to heating and pressure fixing processing by the fixing device 60, and further, is corrected by the curl correction device 70. After the curl correction processing, the sheet is discharged to the first sheet storage unit 91 or the second sheet storage unit 92.

-Function of heat shield parts-
While such an imaging process is performed, the heat shield component 100 operates as follows.
In this example, as shown in FIG. 12, the sheet S heated through the fixing device 60 is forcibly cooled by the airflow from the plurality of blower fans 131 when passing through the curl correction device 70. Here, when the plurality of blower fans 131 are driven, the outside air outside the apparatus casing 21 is sucked through the air supply passage 133 by the air supply duct 132 and is supplied to the space portion on the fixing device 60 side. The air flow from 131 functions to cool the sheet S.
Further, the air in the space portion on the fixing device 60 side is discharged to the outside from the exhaust opening 150 via the exhaust duct 151 by driving the exhaust fan 156. At this time, the air flow supplied to the fixing device 60 side space by the blower fan 131 acts as a cooling air for the sheet S, and the temperature rises accordingly, but is integrated with the air flow flowing into the exhaust opening 150. Become exhausted.
Therefore, in this example, the developer cartridge 38 (38d) of black (K) is disposed in the vicinity of the fixing device 60 and the curl correcting device 70, but the ambient temperature of the fixing device 60 side space extremely rises. There is no concern that the heat from the fixing device 60 side space portion is blocked by the vertical direction partition plate 101 of the heat shield part 100, so that the heat from the fixing device 60 side space portion is black (K) developer cartridge There is no concern affecting 38 (38d).

Furthermore, in the present embodiment, since the lateral partition plate 110 of the heat shield 100 is disposed between the fixing device 60 and the secondary transfer device 50, the heat in the space portion on the fixing device 60 side is two. The situation affecting around the next transfer device 50 is suppressed. The suppression action will be described in detail in the later-described comparison mode 1.
Furthermore, in the present embodiment, since the vertical direction partition plate 101 and the horizontal direction partition plate 110 of the heat shield component 100 are bridged between the opposing frame members 21 f and 21 r of the device case 21, The thermal component 100 functions as one beam member of the device case 21 and is effective in enhancing the overall rigidity of the device case 21.
In particular, in the present embodiment, since the protrusion dimension he of the end region Re in the width direction of the sheet S in the lateral partition plate 110 is set longer than the protrusion dimension hc of the middle region Rc, the end region Re The contact area between the opposite end portions of the transverse partition plate 110 and the opposing frame members 21 f and 21 r of the device casing 21 is smaller than in the aspect in which the projection dimension he of the same is the same as the projection dimension hc of the middle region Rc. By increasing it, it is possible to increase the support strength of the beam as the beam member.

Furthermore, in the present embodiment, since the end region Re and the intermediate region Rc of the transverse partition plate 110 are connected via the curved portion 115, the periphery of the fixing device 60 can be compared to the aspect in which both are connected at the corner. The heat shielding area from the space to the space around the secondary transfer device 50 can be increased.
Furthermore, in the present embodiment, the projecting end of the end region Re of the lateral partition plate 110 is formed as a curved portion 116, and the distal end of the lateral partition plate 110 is formed as a hemming bending portion 117. Therefore, even when the sheet S passes through the secondary transfer device 50 toward the fixing device 60, even if the sheet S contacts the leading end of the lateral partition plate 110 of the heat shield part 100, the sheet S is The concern for damage is extremely low.

形態 Form of comparison 1
In order to confirm the heat shielding action by the horizontal direction partition plate 110 of the heat shielding component 100 according to the present embodiment, the influence of the heat shielding action by the vertical direction partition plate 101 is used by using the image forming apparatus according to the first comparative example. The effect of the heat shielding effect was confirmed under the lost condition.
As illustrated in FIG. 13A, the image forming apparatus 20 ′ according to the first comparative example includes an electrophotographic process cartridge (CRU) 200, and the fixing device 210 is installed above the process cartridge 200. In addition, a heat insulating plate 220 corresponding to only the lateral partition plate 110 is installed therebetween. The process cartridge 200 includes a charging device 202, an exposure device 203, a developing device 204, a transfer device 205 for transferring an image on the photosensitive member 201 to a sheet not shown, and a cleaning device 206 around the photosensitive member 201. It is a thing.
In this example, the change in the ambient temperature of the upper part of the process cartridge (CRU) 200 due to the presence or absence of the heat shield 220 was examined. It is understood that the upper temperature can be kept lower in the embodiment equipped with the heat shield 220. From this, it is understood that the heat influence from the fixing device 210 is improved by the provision of the heat shield 220.

  DESCRIPTION OF SYMBOLS 1 ... Device housing | casing, 1f, 1r ... Frame member, 2 ... Image formation part, 2a ... Image carrier, 2b ... Intermediate transfer body, 2c ... Imaging material container, 3 ... Transfer part, 4 ... Fixing part, 5 ... Heat shield parts, 6 ... Longitudinal partition part, 7 ... Horizontal partition part, 8 ... Air supply part, 9 ... Exhaust part, S ... Recording medium

Claims (11)

An image forming unit provided in an apparatus housing and forming an image using a heat fixable image forming material;
A transfer unit which is provided on the side of the image forming unit in the apparatus housing and transfers the image formed by the image forming unit to a recording medium;
A fixing unit which is provided on the side of the image forming unit and above the transfer unit in the apparatus housing, and which heats and fixes at least the image transferred to the recording medium by the transfer unit;
It is provided to partition between the image forming unit and the fixing unit located above the transfer unit in the apparatus housing, and the heat from the fixing unit flows out to the image forming unit side space And heat shield parts to block the
The heat shield component is a vertical partition extending longitudinally to partition between the image forming unit positioned above the transfer unit and the fixing unit;
A horizontal direction partition portion provided in the vicinity of the lower portion of the vertical direction partition portion, and projecting in the horizontal direction that partitions the fixing portion and the transfer portion so as not to block the conveyance path of the recording medium;
An air supply unit provided in the vertical direction partition unit, for supplying cooling air from the image forming unit side space in the apparatus casing to the fixing unit side space;
And an exhaust unit provided in the vertical direction partition unit and discharging heated air from the fixing unit side space in the apparatus casing toward a space other than the imaging unit in the image forming unit side space. An image forming apparatus characterized by In the image forming apparatus according to claim 1,
2. The image forming apparatus according to claim 1, wherein the longitudinal partition portion is bridged between opposing frame members of the device casing positioned on both sides in the width direction intersecting the conveyance direction of the recording medium. In the image forming apparatus according to claim 2,
2. The image forming apparatus according to claim 1, wherein the transverse partition section is bridged between opposing frame members of the apparatus casing positioned on both sides in the width direction of the recording medium. The image forming apparatus according to any one of claims 1 to 3.
2. The image forming apparatus according to claim 1, wherein in the horizontal partition, the end regions located on both sides in the width direction of the recording medium have a projection dimension from the vertical partition longer than in the middle region. In the image forming apparatus according to claim 4,
2. An image forming apparatus according to claim 1, wherein long end areas of projecting dimension located on both sides in the width direction of the recording medium and intermediate areas having short projecting dimensions of said transverse partition section are connected via a curved section. . The image forming apparatus according to any one of claims 1 to 5,
2. The image forming apparatus according to claim 1, wherein the lateral partition has a hemming bending portion at a tip end facing the transport path of the recording medium. The image forming apparatus according to any one of claims 1 to 6.
The image forming apparatus is characterized in that the exhaust unit is disposed closer to the rear side of the apparatus casing than the air supply unit. In the image forming apparatus according to claim 7,
The image forming apparatus, wherein the exhaust unit is disposed below the air supply unit. The image forming apparatus according to any one of claims 1 to 8.
The image forming apparatus according to claim 1, wherein the vertical direction partition unit has an opening in which at least a part of a drive transmission mechanism that transmits a drive force to the fixing unit is installed. The image forming apparatus according to any one of claims 1 to 9.
2. The image forming apparatus according to claim 1, wherein the vertical partition section divides an imaging material container containing an imaging material as a part of the imaging section with the fixing section. An image forming unit provided in an apparatus casing and forming an image using a heat-fixable image forming material, and provided in a side of the image forming unit in the apparatus casing and formed by the image forming unit A transfer unit for transferring the printed image to a recording medium, and a side of the image forming unit in the apparatus housing and above the transfer unit, the image transferred to the recording medium by the transfer unit Used in an image forming apparatus comprising at least a fixing unit for heat fixing, and provided so as to partition between the image forming unit and the fixing unit located above the transfer unit in the apparatus housing A heat shielding component that blocks heat from the fixing unit from flowing out to the imaging unit side space,
A longitudinal partitioning portion extending in the longitudinal direction so as to partition between the image forming portion located above the transfer portion and the fixing portion;
A horizontal direction partition portion provided in the vicinity of the lower portion of the vertical direction partition portion, and projecting in the horizontal direction that partitions the fixing portion and the transfer portion so as not to block the conveyance path of the recording medium;
An air supply unit provided in the vertical direction partition unit, for supplying cooling air from the image forming unit side space in the apparatus casing to the fixing unit side space;
An exhaust unit provided in the vertical direction partition unit and discharging heated air from the fixing unit side space in the apparatus casing toward a space other than the imaging unit in the image forming unit side space;
Heat shielding parts with.

Images