JP2008170695A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress image quality defects occurring due to the heat that a recording medium is eventually possessed by heat fixing in a both side image forming apparatus in which heat fixing is performed. <P>SOLUTION: A duct 610 is disposed in a space formed between a transfer section 332 of a marking unit 21 and a recursion conveyance way forming section 512 of a both-side conveyance way 510. The duct 610 is provided with a duct 620 to forcibly form the flow of air within a cavity, and to take in the air outside a casing of a relatively low temperature. The heat fixed recording medium already recorded on one side and the recursion conveyance way forming section 512 warmed by the heat of the recording medium can be cooled by the cooling effect of the air within the duct 610. The transmission of their heat to the transfer section 332 of the marking unit 32 can be suppressed by a heat insulation effect. As a result, the heat fixed recording medium already recorded on the one side passes the neighborhood of the marking unit 32 and thereby the image quality defects due to the heat eventually possessed in the recording medium by the heat fixing can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording apparatus and an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses such as laser printers and copying apparatuses that form images on recording media such as paper (also called recording paper) and OHP (OverHead Projector) sheets are widely used in companies and homes. Some image forming apparatuses are capable of forming images on both sides of a recording medium (referred to as double-sided printing) (hereinafter also referred to as double-sided image forming apparatuses).

  In an electrophotographic double-sided image forming apparatus, in general, a recording medium is sent to an image forming unit called an image forming unit, a transfer unit, an image output unit, or the like of the apparatus to form an image on one side (referred to as a front surface) of the recording medium. After transferring and fixing by heat and pressure (hereinafter referred to as heat fixing), the front and back of the recording medium on which single-side recording has been performed are reversed, and a conveyance path called a double-side conveyance path or a reverse conveyance path is formed. Then, the image is sent again to the image forming unit, and the image is transferred to the other side (referred to as the back side) to form images on both sides of the recording medium (see, for example, Patent Document 1).

JP 2000-198574 A

  An object of the present invention is to make a recording apparatus having a recursive conveyance unit less susceptible to the influence of a recording medium passing through a recursive conveyance path.

  The invention according to claim 1 is a recording unit that performs recording on a recording medium, a heat treatment unit that uses heat to process an image recorded on the recording medium by the recording unit, and a vertical direction of the recording unit A recursive conveyance path that is positioned below and recursively conveys the recording medium that has passed through the heat treatment section to the recording section, and a guide that is disposed between the recording section and the recursive conveyance path and that is close to the recursive conveyance path. A recording apparatus having an air path.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first opening provided in a part of the recursive conveyance path facing the air guide path, and the first And a second opening provided at a portion facing the recursive conveyance path.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, it further includes a first air flow generating means for generating an air flow in the air guide passage.

  According to a fourth aspect of the invention, in the third aspect of the invention, the first air flow generating means is configured to suck out air from the air guide passage.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the image forming portion and the first air guide path are further disposed, and a cavity is formed therein. The cavity member is provided.

  The invention described in claim 6 is characterized in that in the invention described in claim 5, there is further provided a second air flow generating means for generating an air flow in the hollow member.

  According to a seventh aspect of the invention, in the sixth aspect of the invention, the first air flow generating means also serves as the second air flow generating means.

  According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the recording unit transfers an image holding member holding an image and an image formed on the image holding member to a recording medium. An image forming apparatus having a transfer section that performs heat transfer, and the heat treatment section fixes the image transferred to the recording medium by the transfer section to the recording medium using heat. It is characterized by that.

  According to the first aspect of the present invention, there is provided a recording medium that can obtain a cooling action and a heat insulation action by the air in the air guide path, and that passes through the recursive conveyance path as compared with the case where this configuration is not provided. The influence on the recording unit can be reduced.

  According to the second aspect of the present invention, when the recording medium passes through the recursive conveyance path, the heat received from the heat treatment section, the generated water vapor, and the like can be discharged from the air guide path, and the influence on the recording section. Can be further reduced.

  According to the third aspect of the present invention, it is possible to reduce the influence on the recording portion more effectively by generating a positive air flow in the air guide passage.

  According to the fourth aspect of the present invention, the heat and water vapor of the recording medium can be actively sucked by setting the inside of the air guide path to a state where the atmospheric pressure is lower than the recursive transport path.

  According to the fifth aspect of the present invention, the influence on the recording portion can be further reduced by the hollow member disposed between the air guide path heated by the heat from the recording medium and the recording portion.

  According to the sixth aspect of the present invention, by generating a positive air flow in the cavity, it is possible to further reduce the influence on the recording unit even with respect to the fifth aspect of the present invention.

  According to invention of Claim 7, compared with the case where this structure is not provided, a cooling effect can be heightened, making an apparatus small and low-cost.

  According to the eighth aspect of the present invention, the influence on the image forming unit due to heat and water vapor from the recording medium in the recursive conveyance path in the image forming apparatus is reduced as compared with the case where the present configuration is not provided. I can do it.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the following, an example in which an electrophotographic image forming apparatus having a print (printer) function and a copy (copy) function in combination is used as a recording apparatus will be described. However, this is an example, and the target recording apparatus is not limited to an electrophotographic image forming apparatus. All of the embodiments described later can be similarly applied to all apparatuses having a function of recording on a recording medium such as paper (recording paper) or an OHP sheet and having a recursive conveyance path. As an example, the recording apparatus of the present invention may be an ink jet recording apparatus having an ink drying mechanism.

  The image output terminal 1 is an example of an image forming apparatus according to the present invention. For example, the image output terminal 1 is a so-called multifunction machine having a copying function, a page printer function, and a facsimile transmission / reception function, and is configured as a digital printing apparatus. ing.

  The image output terminal 1 is roughly a controller having an image reading unit 10 for reading a document, an image processing function for performing desired image processing on input image data, and a control function for controlling the operation of the entire terminal. Print from either the image forming unit 20 or the image output unit 30 that forms and outputs a visible image on a predetermined recording medium based on the image data from the controller unit 20, and the built-in paper feed tray 82 or the manual feed tray 83 A paper feed unit 80 is provided that transports a recording medium such as paper or an OHP sheet (hereinafter, typically described as “paper”) to the image output unit 30.

  Hereinafter, the configuration of the present invention in the image output unit 30 of the first embodiment (first example) will be described in detail.

  As illustrated, the image output unit 30 according to the first embodiment (first example) has a predetermined process speed based on image data read by the image reading unit 10, print data acquired via the connection cable 90, and the like. Are provided with a marking unit 32 as a recording unit for forming an image on the paper being conveyed, a fixing unit 33 as a heat treatment unit, and a duplex copying unit 34 including a recurring conveyance path.

  In the present embodiment, the marking unit 32 employs a system that forms an image using an electrophotographic process. Specifically, the marking unit 32 includes, as a main element, a photosensitive drum 312 that is an example of an image carrier that has a photoconductive photosensitive layer and carries an image (hereinafter referred to as a toner image) formed of toner. A photoconductor unit 310, a charger 314 for uniformly charging the photoconductor drum 312, and a document which is an exposure means for forming a latent image by exposing the photoconductor drum 312 with laser light based on input image information. And a scanning unit 316.

  Further, the marking unit 32 develops the latent image on the photosensitive drum 312 to form a toner image, and transfers the toner image carried on the photosensitive drum 312 onto the conveyed paper. The transfer unit 332, a separation unit that separates the sheet onto which the toner image has been transferred from the photosensitive drum 312, and a transfer unit 330 including a conveyance path, and the toner remaining on the photosensitive drum 312 after being transferred to the sheet And a cleaning unit 340 as a cleaning means for removing water.

  The charger 314, the writing scanning unit 316, the developing unit 320, the transfer unit 330, and the cleaning unit 340 are disposed around the photosensitive drum 312. The image output unit 30 first includes a fixing unit 33 on the paper discharge unit 36 side of the transfer unit 330, and further, on the paper discharge unit 36 side of the fixing unit 33, the single-side printed paper is directly used on the paper discharge unit 36 side. A transport path switching unit 350 that switches between transporting to the duplex copying unit 34 side.

  Among the units arranged around the photosensitive drum 312, the transfer unit 330 is disposed below the photosensitive unit 310. A double-sided copying unit 34 is disposed below the transfer unit 330 and the fixing unit 33.

  Although not shown in FIG. 2, as shown in FIG. 1, a sheet feeding tray 82 that can store a plurality of sheets in a stacked state is disposed below the duplex copying unit 34. The sheet conveyed from the sheet feed tray 82 is transferred from the lower left side of the drawing to a transfer area A formed between the photosensitive drum 312 of the photosensitive unit 310 and the transfer unit 330 (specifically, the transfer unit 332). It is sent.

  In such a configuration, the photosensitive drum 312 is rotated in the direction of an arrow by a driving unit such as a motor, a gear, and a pulley (not shown), and is uniformly charged by the charger 314 and synchronized with the leading edge of the paper. The latent image formation by the writing scanning unit 316 that has started exposure and the development by the developing unit 320 are performed, and a toner image based on the input image information is formed on the photosensitive drum 312.

  The toner image formed on the photoconductive drum 312 is transferred by the transfer unit 330 onto the paper conveyed to the transfer area A formed between the photoconductive drum 312 and the transfer unit 330 via the conveyance path. The

  The sheet onto which the toner image has been transferred is further separated from the photosensitive drum 312 by a separator (not shown) attached to the transfer unit 330 and conveyed to the fixing unit 33, where it is heated and pressurized. Thus, the toner image is fixed on the paper.

  On the other hand, the photosensitive drum 312 having the toner image transferred onto the sheet continues to rotate, and the toner remaining on the photosensitive drum 312 is removed by the cleaning unit 340 to prepare for the next image formation.

  As shown on the left side of the drawing in the image output unit 30, various conveyance rollers (including both one and a pair) 418 are provided between the paper feed tray 82 and the transfer area A. A paper feeding / conveying path 410 (generally a range of arrows at both ends in the drawing), which is an example of a conveying unit configured to convey paper from the paper feeding tray 82 or the manual feed tray 83 to the transfer area A, is provided.

  The conveyance roller 418 is not limited to one and a plurality of conveyance rollers 418 may be provided. In the figure, each reference numeral is followed by a lowercase English reference. In the description in the text, when they are distinguished, they are described with the reference, but when there is no need for special distinction, they are described without the reference. The same applies to the conveyance rollers of the conveyance path switching unit 350 and the double-sided conveyance path 510 described later.

  For example, in the first embodiment (first example), the paper feed conveyance path 410 is a pair of loop forming rollers 418a that are loop forming means for conveying the paper conveyed from the paper supply unit 80 and the double-sided conveyance path 510 (not shown). And a registration roller 418b which is an abutting means for resuming the conveyance after the sheet conveyed by the loop forming roller 418a is once abutted.

  The loop forming roller 418a and the registration roller 418b constitute a bending correcting unit that forms a loop on the conveyed paper and corrects the paper bending. Preferably, as shown in the figure, loop formation guides 420 and 422 are used as guide members for guiding the conveyance of the paper between and in the vicinity of the loop formation roller 418a and the registration roller 418b in order to surely perform the loop formation. It is preferable to provide.

  The loop formation guides 420 and 422 have a mountain shape in cross section, and function as a loop formation guide that guides the paper in a loop shape along the loop formation guides 420 and 422.

  The conveyance path switching unit 350 includes various conveyance rollers (including both one and a pair) 358, and the like. The single-side printed paper fixed by the fixing unit 33 is printed on the double-sided copying unit 34 side. Constitutes a part of the re-feeding means for transporting the paper.

  The double-sided copying unit 34 used for double-sided printing re-feeds the single-sided printed paper with an image formed on one side upside down and transports it again to the transfer area A between the photosensitive drum 312 and the developing unit 320. It constitutes the main part of the means.

  The duplex copying unit 34 includes a recursive path forming member 512 and various transport rollers (including both one and a pair) 518 as a recursive transport path, and is transported from the transport path switching unit 350. A double-sided conveyance path 510 (generally a range of arrows at both ends in the drawing), which is an example of a conveyance unit that conveys the printed single-sided printed sheet to the paper feed conveyance path 410 side, is provided.

  The recursive transport path forming member 512 has a role of guiding the paper transported by the transport rollers 518 b to 518 d to the paper feed transport path 410.

  The conveyance path switching unit 350 and the double-sided copying unit 34 form a component for refeeding the paper on which the image is formed in the transfer area A to the transfer area A. The conveyance path switching unit 350 discharges the single-sided printed paper on which the toner image is fixed and discharged by the fixing unit 33 as it is to the discharge unit 36 side, and transfers it to the duplex copying unit 34 side for duplex printing. Switch the transport path with.

  As shown in the lower right side of the drawing in the image output unit 30, a sheet reversing mechanism 360 (generally a diagram) is an example of a reversing unit that reverses the front and back of the sheet between the transport path switching unit 350 and the duplex copying unit 34. A range of arrows at both ends is formed.

  When the image-formed paper (including both single-sided printed paper and double-sided printed paper) is discharged as it is, that is, with the image-formed side facing up, the transport path switching unit 350 outputs the paper outside the machine. The paper is immediately discharged to the paper unit 36.

  In addition, when the paper on which the image is formed is reversed and discharged, that is, when the image-formed surface is discharged downward, the transport path switching unit 350 removes the paper discharged from the fixing unit 33. The conveyance roller 358a once conveys the paper in the direction of the paper reversing mechanism 360, reverses the conveyance direction after the paper passes through the conveyance path switching unit 350, that is, reverses the front and back by performing a switchback, and the conveyance roller 358b discharges to the discharge unit 36 side outside the apparatus.

  On the other hand, when an image is formed on the back side of the single-side printed paper, the conveyance path switching unit 350 conveys the single-side printed paper discharged from the fixing unit 33 toward the paper reversing mechanism 360 by the conveyance roller 358a. Then, after the sheet passes through the conveyance path switching unit 350, the conveyance direction is reversed, that is, the paper is reversed by performing switchback, and the double-side conveyance path 510 is conveyed by the conveyance rollers 518a and 518b of the duplex copying unit 34. Then, the paper is drawn to the side and further conveyed to the paper feed conveyance path 410 side.

  The single-side printed paper that has been turned upside down and conveyed by the conveyance rollers 518c and 518d on the duplex conveyance path 510 of the duplex copying unit 34 is fed at the merge section 520 shown in the lower left side of the drawing in the image output section 30. 410, and is conveyed to a transfer area A formed between the photosensitive drum 312 and the transfer unit 330 in the same manner as the paper feed from the paper feed tray 82 and the manual feed tray 83.

  Here, the image output unit 30 of the first embodiment (first example) is guided to the paper reversing mechanism 360 side of the space formed between the duplex conveyance path 510 and the transfer unit 330 in the duplex copying unit 34. A long duct 610 is provided as an air path.

  The duct 610 is disposed across the front side and the depth side of the paper surface. That is, the double-sided conveyance path 510 is disposed so as to be substantially orthogonal to the paper conveyance direction of the recursive conveyance path forming member 512.

  In the duct 610 used in the first embodiment (first example), the lower surface on the recursive conveyance path forming member 512 side is opened, and the recursive conveyance path forming member 512 is configured as a part of the duct 610. Yes. Thereby, as a whole, an air guide path having a generally tunnel type structure capable of positively forming an air flow is formed.

  In addition, the image output unit 30 of the first embodiment (first example) positively sends an air flow into the duct 610 at one or both ends of the long duct 610 as necessary. The fan 630 is provided as a forced convection means that is formed in a manner to allow the heat radiation function and the heat insulation function to act (refer to FIG. 3 described later for details). The fan 630 forcibly forms an air flow in the cavity, or air outside the casing of the relatively low-temperature fan 630 (simply referred to as “outside air”) is actively taken into the air guide path.

  Here, “if necessary” means that the heat or water vapor from the paper is sucked and exhausted by a fan 630 as a forced convection device, thereby increasing the temperature due to the paper heat of each unit such as transfer, development, and charging. It means a case where the purpose is to enhance the effect of heat countermeasures for paper to improve the problem of condensation due to water vapor.

<Fan Arrangement Example; First Embodiment>
FIG. 3 is a diagram illustrating an arrangement example of the fans 630 in relation to the air guide path (duct 610) and the recursive conveyance path. In FIG. 3, not only the relationship with the recursive conveyance path forming member 512 as the recursive conveyance path, but also the paper reversal conveyance path 364 of the paper reversal mechanism 360 used in the first embodiment (second example) described later. The relationship is also shown in parentheses.

  First, in any of the first arrangement example shown in FIG. 3A and the second arrangement example shown in FIG. 3B, individual plate members 514 are connected to form a recurring conveyance path forming member. ing. In the figure, one of the plate-like members 514 is shown.

  Angles 515 that prevent the sheet from dropping off in the width direction are provided on part of both sides in the width direction of the plate-like member 514. An opening 516 is formed in the plate member 514. The number of openings 516 formed is arbitrary as necessary. In the drawing, two openings 516 are arranged in a line in the width direction of the plate-like member 514 (that is, the recurring conveyance path forming member 512).

  In the duct 610 of the present embodiment, as shown in FIG. 3D, wall surfaces 610a, 610b, and 610c are provided on the upper surface and the side surfaces on both sides of the marking unit 32, respectively. The bottom surface on the plate-like member 514 side that constitutes a structure having an open opening 610d.

  The opening 610d is such that the ends of the wall surfaces 610b and 610c on both sides on the plate-like member 514 side are in close contact with the plate-like member 514 (closely close to each other or close enough to make the gap as small as possible). By arranging, the plate-like member 514 is configured as a part of the duct 610. Thereby, the opening 610d of the duct 610 is complemented by the plate-like member 514, and as a whole, an air guide path having a generally tunnel-type structure capable of positively forming an air flow is formed.

  For example, in the first arrangement example shown in FIG. 3A, a fan 630a for sucking outside air is placed at one end of the duct 610 (the right-side opening 610e), and the air flowing through the duct 610 Arranged upstream. In this case, the air sucked into the duct 610 by the fan 630a passes through the duct 610 and is further discharged from the other end of the duct 610 (the left opening 610f in the drawing).

  On the other hand, in the second arrangement example shown in FIG. 3B, an air exhaust fan 630b is provided at the other end of the duct 610 (the left opening 610f in the figure), and the air flowing through the duct 610 is It is arranged downstream. In this case, outside air is sucked into the duct 610 from the end opposite to the end where the fan 630b is provided (the opening 610e on the right side in the figure), and is further exhausted by the fan 630b through the duct 610. In this arrangement, since the inside of the duct 610 has a negative pressure as compared with other portions, the air in the recursive conveyance path is actively drawn into the duct 610. In this case, it is more effective to configure the air to flow into the opening 610e on the right side from the outside of the image forming apparatus.

  As in the third arrangement example shown in FIG. 3C, the first arrangement example shown in FIG. 3A and the second arrangement example shown in FIG. One end (right opening 610e in the figure) is provided with a fan 630a for sucking outside air, and the other end of the duct 610 (left opening 610f in the figure) is provided with an air discharge fan 630b. It is good also as a structure.

  In any of the first arrangement example shown in FIG. 3A, the second arrangement example shown in FIG. 3B, and the third arrangement example shown in FIG. 3C, the fans 630a and 630b are forced. The one side printed paper passing through the opening surface side of the duct 610 or the opening surface side of the duct 610 by flowing the externally sucked outside air into the duct 610, that is, by flowing cooling air in the direction perpendicular to the paper conveyance direction. The outside air is blown onto the surface of the plate-like member 514 that passes through or is fixedly arranged, and the single-side printed paper and the plate-like member 514 (that is, the recurring conveyance path forming member 512) are cooled. The air in the duct 610 warmed by this cooling action is discharged from the other end (the left end in the figure). Further, water vapor generated from the single-side printed paper is discharged together with the air in the duct 610.

  In addition, an opening 516 is formed in the plate-like member 514, and the air in the duct 610 and the air in the recursive conveyance path 510 can be circulated through the opening 516.

  In this embodiment, the fan 630 is provided. However, the heat discharge by the air flow in the air guide path formed by the duct 610 and the recurring transport path forming member 512 (specifically, the plate-like member 514) is used. Then, the heat of the single-side printed paper is sucked, the recurring conveyance path forming member 512 (specifically, the plate-like member 514) is cooled, or the heat from the single-side printed paper or the plate-like member 514 is insulated. In doing so, it is not essential to provide the fan 630.

  Openings 610e and 610f are provided at both ends of the duct 610. Even if the openings 610e and 610f are provided, the air naturally flows in the duct 610 due to the air flow in the image forming apparatus or the temperature difference of the air, thereby obtaining a cooling action and a heat insulation action by discharging heat. Because it can.

<First embodiment; paper reversing conveyance path>
FIG. 4 is a side sectional view showing a second example of the first embodiment of the detailed configuration example of the image output unit 30 of the image output terminal 1. The image output unit 30 of the first embodiment (second example) replaces the double-sided conveyance path 510 in the first embodiment (first example) as a recursive conveyance path for conveying printed paper in the duplex copying unit 34. The sheet reversing conveyance path 364 is characterized in that it is provided directly below the marking unit 32.

  The image output unit 30 of the first embodiment (second example) is configured to include a paper reversal conveyance path 364 as a recursive conveyance path through which printed paper is conveyed in the duplex copying unit 34, and guide the paper reversal conveyance path 364. It has the 1st characteristic in the point constituted as a part of air course. This is the same as the first feature in which the double-sided conveyance path 510 is configured as a part of the air guide path in the image output unit 30 of the first embodiment (second example).

  Other points are generally the same as those of the image output unit 30 of the first embodiment (first example), and the second and third features of the image output unit 30 of the first embodiment (first example) are the same. Have. Hereinafter, the difference from the image output unit 30 of the first embodiment (first example) will be mainly described. In addition, the same code | symbol is attached | subjected and demonstrated about the functional element similar or similar to 1st Embodiment (1st example).

  As shown in the figure, the image output unit 30 of the first embodiment (second example) has a predetermined process speed based on image data read by the image reading unit 10, print data acquired via the connection cable 90, and the like. A marking unit 32, a fixing unit 33, and a duplex copying unit 34, which form an image using an electrophotographic process for forming an image on a sheet conveyed by the printer. This is the same as in the first embodiment (first example).

  The image output unit 30 of the first embodiment (second example) first separates the paper on which the toner image formed on the photoconductive drum 312 has been transferred by the transfer unit 330 from the photoconductive drum 312, and then removes the paper. A conveyance path 540 for conveying to the fixing unit 33 is provided between the transfer unit 330 and the fixing unit 33.

  Further, the image output unit 30 of the first embodiment (second example) reverses the case where the paper (single-sided printed paper or double-sided printed paper) discharged by the fixing unit 33 is discharged to the outside as it is. A transport path switching unit 350 that switches the transport path when the paper is discharged later or re-feeded to form an image on the back surface, a paper reversing mechanism 360 that reverses the front and back of the paper that is re-fed, and a paper reversing mechanism 360 The re-feeding path 370 is substantially the same as the double-sided conveyance path 510 of the first embodiment (first example) for re-feeding the paper that has been reversed in the step 1 to the marking unit 32.

  The transport path switching unit 350 is an example of a unit that transports the paper fixed by the fixing unit 33 to the paper reversing mechanism 360 without transporting the paper to the paper discharge unit 36, and includes a transport belt 352 and a switching lever 356. And a pair of conveying rollers 358a, 358b, 358c.

  The sheet reversing mechanism 360 includes a sheet guiding unit 362 that guides a single-side printed sheet to be switched back, a sheet reversing conveyance path 364, and a pair of conveyance rollers 368 that can rotate left and right. The sheet reversal conveyance path 364 extends to the lower part of the transfer unit 330 of the marking unit 32.

  In the refeed path 370, various pairs of transport rollers 378 are provided in order to return the switched back single-side printed paper whose front and back are reversed by the paper reversing mechanism 360 to the marking unit 32 again through the refeed path 370. Is provided.

  The paper feed transport path 410 is transported by a pair of loop forming rollers 418a which are loop forming means for transporting paper transported from the paper feed section 80 and the refeed paper path 370 which are not shown, and the loop forming rollers 418a. It has a pair of registration rollers 418b which are abutting means for resuming conveyance after the paper is once abutted, and a general pair of conveyance rollers 418c.

  The loop forming roller 418a and the registration roller 418b constitute a bending correcting unit that forms a loop on the conveyed paper and corrects the paper bending. Preferably, as shown in the figure, a loop forming guide 420 functioning as an upper guide as a guide member for guiding the conveyance of the sheet between the loop forming roller 418a and the registration roller 418b in order to surely perform the loop formation. It is preferable to provide a loop forming guide 422 that functions as a lower guide.

  The loop formation guide 420 has a mountain shape in cross section, and functions as a loop formation guide that guides the paper in a loop shape along the loop formation guide 420. A pair of transport rollers 418c is provided on the downstream side of the loop formation guides 420 and 422. Between the transport roller 418c and the registration roller 418b, a light source 426 and a detection unit 428, which are means for detecting the transport state of the paper, are provided. Is provided.

  In such a configuration, when an image-formed sheet (including both single-sided printed paper and double-sided printed paper) is discharged as it is, that is, with the image-formed side facing upward, the conveyance path switching unit 350 Falls the switching lever 356 toward the fixing unit 33 and immediately discharges the sheet to the sheet discharge unit 36 outside the apparatus.

  Also, when paper is discharged with the front and back sides of the image-formed paper turned upside down, that is, when paper is discharged with the image-formed side down, the transport path switching unit 350 moves the switching lever 356 to the paper discharge unit 36 side. The paper discharged from the fixing unit 33 is once transported in the direction of the paper reversing mechanism 360 by the transport rollers 358a and 358b, and after the paper passes the switching lever 356, the transport direction is reversed by the transport roller 358b. In other words, the front and back are reversed by performing a switchback, and the paper is again discharged to the paper discharge unit 36 side by the conveying roller 358b. That is, the transport path switching unit 350 of the first embodiment (second example) itself includes a paper reversing mechanism.

  On the other hand, when forming an image on the back side of the single-sided printed paper, the conveyance path switching unit 350 tilts the switching lever 356 toward the paper discharge unit 36 so that the single-sided printed paper discharged from the fixing unit 33 is conveyed to the conveyance roller 358a. , 358b, 358c, 358d are conveyed in the direction of the sheet reversing mechanism 360. Then, the sheet is reversed toward the sheet re-feeding path 370 by the conveying roller 368 of the sheet reversing mechanism 360, and the conveying direction is reversed by the conveying roller 368. Transport to the path 370 side.

  The one-side printed paper that has been turned upside down and conveyed by the respective conveying rollers 378 in the refeed path 370 is merged into the sheet feed conveyance path 410 at the merge section 520 shown in the lower right side of the drawing in the image output section 30. Similarly to the paper feed from the paper feed tray 82 and the manual feed tray 83, the paper is conveyed to the transfer area A formed between the photosensitive drum 312 and the transfer unit 330.

  Here, the image output unit 30 of the first embodiment (second example) has a sheet heat suction and conveyance path in a space formed between the sheet reversal conveyance path 364 and the transfer unit 330 in the duplex copying unit 34. A long duct 610 having both functions of cooling is provided.

  The duct 610 is disposed on the front side and the depth side of the sheet. That is, it is arranged so as to be substantially orthogonal to the paper conveyance direction of the paper reversal conveyance path 364.

  The duct 610 used in the first embodiment (second example) has a lower surface on the side of the paper reversal conveyance path 364, and the paper reversal conveyance path 364 is configured as a part of the duct 610. Thereby, as a whole, an air guide path having a generally tunnel type structure capable of positively forming an air flow is formed.

  Further, the image output unit 30 of the first embodiment (second example) positively sends air flow into the duct 610 at one or both ends of the long duct 610 as necessary. The fan 630 is provided as a forced convection means that is formed in a manner to allow the heat radiation function and the heat insulation function to act. This is the same as in the first embodiment (first example).

  The arrangement of the fan 630 in relation to the duct 610 and the paper reversal conveyance path 364 is the same as that in which the recursive conveyance path forming member 512 is replaced with the paper reversal conveyance path 364 as shown in parentheses in FIG. Similar to the description in FIG. 3, an opening 366 corresponding to the opening 516 is formed in the sheet reversal conveyance path 364. As with the openings 516, the number of openings 366 is arbitrary. In addition, since the functions and effects of the sheet reversing conveyance path 364 and the opening 366, the duct 610, and the fan 630 of the sheet reversing mechanism 360 are the same as those in the first embodiment (first example), detailed description is given here. I will omit the explanation.

<Second embodiment: Double-sided conveyance path>
FIG. 5 is a side sectional view showing a first example of the second embodiment of the detailed configuration example of the image output unit 30 of the image output terminal 1. The image output unit 30 of the second embodiment (first example) includes a double-sided conveyance path 510 as a recursive conveyance path through which printed paper is conveyed in the double-sided copying unit 34. It is characterized in that a long duct 620 is provided as a hollow member on the transfer unit 330) side.

  In other words, the air guide path (duct 610) and the hollow member (620) are arranged in two layers in the space formed between the paper reversal transport path 364 as the recursive transport path and the marking unit 32. Yes.

  As with the duct 610, the duct 620 is disposed on the front side and the depth side of the page. That is, the double-sided conveyance path 510 is disposed so as to be substantially orthogonal to the paper conveyance direction of the recursive conveyance path forming member 512.

  The duct 610 is composed of the heat radiation action of the paper and the recursive conveyance path, that is, the heat absorption action of the paper using the air flow in the wind tunnel and the heat discharge, the cooling action of the recursive conveyance path, and the air in the duct 610 itself. The duct 620 according to the present embodiment has a heat insulating function to prevent the heat of the single-side printed paper and the recurring conveyance path forming member 512 from being transmitted to the marking unit 32 side. It has only a heat insulating effect to prevent the heat of the printed paper and the recurring transport path forming member 512 from being transmitted to the marking unit 32 side. However, even if there is some air flow between the duct 610 and the duct 620, the effect of the present invention is not hindered.

  Further, the image output unit 30 of the second embodiment (first example) has an air flow in the duct 620 at one or both ends of the added long duct 620 as necessary. The fan 640 is provided as a forced convection means for positively forming the air and causing the heat insulation function to act (refer to FIG. 6 described later for details).

  Here, “if necessary” means that the air in the fan 640 heated by the heat from the paper is exhausted by the fan 640 as a forced convection device, so that the paper heat of each unit such as transfer, development, and charging It means the case where the purpose is to enhance the effect of paper heat countermeasures to improve the problem of temperature rise due to.

  In addition, when providing the fan 630 with respect to the duct 610 demonstrated in 1st Embodiment, you may comprise so that one fan may serve as fan 630,640. That is, one fan 650 is used for both the duct 610 on the plate-like member 514 side which is the first cavity member and the duct 620 on the marking unit 32 (particularly the transfer unit 330) side which is the second cavity member. Alternatively, refer to FIG. 6 to be described later for details.

<Fan Arrangement Example; Second Embodiment>
FIG. 6 is a diagram illustrating an arrangement example of the fans 640 in relation to the hollow member (duct 620) and the recursive conveyance path. In FIG. 6, not only the relationship with the recursive conveyance path forming member 512 as the recursive conveyance path, but also the paper reversal conveyance path 364 of the paper reversal mechanism 360 used in the second embodiment (second example) described later. The relationship is also shown in parentheses. Note that, here, the fan 630a is disposed on the upstream side of the duct 610 and the fan 630b is disposed on the downstream side, but only one of the fans 630a and 630b is shown. You may combine with the aspect arrange | positioned.

  For example, as shown in FIG. 6A, ducts 620 added to the upper part of the duct 610 (on the marking unit 32 side) are wall surfaces 620a and 620b on the upper surface and the side surfaces on the marking unit 32 side and the lower surface on the duct 610 side, respectively. , 620c, 620d. That is, a wall surface 620d may be provided also on the duct 610 side, and the duct 620 itself may form a cavity having a generally tunnel type structure that can actively form an air flow. In this case, the duct 620 need not be in close contact with the duct 610.

  Alternatively, as shown in FIG. 6B, wall surfaces 620a, 620b, and 620c are provided on the upper surface on the marking unit 32 side and the side surfaces on both sides, whereas the lower surface on the duct 610 side is opened 620g. It is good also as a structure provided with. The opening 620g is arranged so that the end of the wall 610a side of the duct 610 on both wall surfaces 620b and 620c is in close contact with the wall surface 610a (closely close to each other so that the gap is as small as possible). Thus, the wall surface 610 a on the duct 620 side of the duct 610 is configured as a part of the duct 620. In effect, the structure is similar to the duct 610. Thereby, the opening surface of the duct 620 is complemented by the wall surface 610a of the duct 610, and as a whole, a cavity having a generally tunnel-type structure capable of positively forming an air flow is formed. Of course, the duct 610 and the duct 620 may be integrally formed.

  For example, in the first arrangement example (basic form) shown in FIG. 6 (C1), a fan 640a for sucking outside air is placed at one end of the duct 620 (the opening 620e on the right side in the figure), and the inside of the duct 620 is placed. Arranged upstream of the flowing air. In this case, the air sucked into the duct 620 by the fan 640a passes through the duct 620 and is further discharged from the other end of the duct 620 (the left opening 620f in the drawing).

  In addition, when providing the fan 630a with respect to the duct 610 like the 1st example of arrangement | positioning (modified example) shown in FIG.6 (C2), even if it comprises so that one fan 650a may serve as the fans 630a and 640a. Good. On the other hand, in the second arrangement example (basic form) shown in FIG. 6 (D2), an air exhaust fan 640b is placed in the duct 620 at the other end of the duct 620 (left opening 620f in the figure). It is arranged downstream of the flowing air. In this case, outside air is sucked into the duct 620 from the end opposite to the end where the fan 640b is provided (the opening 620e on the right side in the drawing), passes through the duct 620, and is further discharged by the fan 630b.

  Further, as in the second arrangement example (modification) shown in FIG. 6D2, when the fan 630b is provided for the duct 610, one fan 650b may be configured to serve as the fans 630b and 640b. Good.

  Further, as in the third arrangement example (basic form) shown in FIG. 6 (E1), the first arrangement example (basic form) shown in FIG. 6 (C1) and the second arrangement example (basic form) shown in FIG. 6 (D1). ) Is provided at one end of the duct 620 (right opening 620e in the figure), and a fan 640a for sucking outside air is provided at the other end (left opening 620f in the figure) of the duct 620. It is good also as a structure which provides the fan 640b for air discharge.

  Also in this case, when the fans 630a and 630b are provided for the duct 610 as in the third arrangement example (modified example) shown in FIG. 6E2, one fan 650a also serves as the fans 630a and 640a. In addition, one fan 650b may be configured to serve as the fans 630b and 640b.

  In this example, the fan 640 (or 650) is provided. However, the heat from the air flow in the cavity of the duct 620 is used to block the heat from the single-side printed paper and the plate-like member 514. It is not essential to provide the fan 640 (or 650).

  Openings 620e and 620f are provided at both ends of the duct 620. This is because even if the openings 620e and 620f are provided, air naturally flows in the duct 620, and a heat insulating effect by heat discharge can be obtained.

<Second Embodiment: Paper Reversal Conveyance Path>
FIG. 7 is a side sectional view showing a second example of the second embodiment of the detailed configuration example of the image output unit 30 of the image output terminal 1. The image output unit 30 of the second embodiment (second example) replaces the double-sided conveyance path 510 in the second embodiment (first example) as a recursive conveyance path through which the printed paper in the double-sided copying unit 34 is conveyed. The sheet reversing conveyance path 364 is characterized in that it is provided directly below the marking unit 32. This is the same as in the first embodiment (second example).

  On the premise of such a configuration, the image output unit 30 of the second embodiment (second example) is provided between the sheet reversal conveyance path 364 and the transfer unit 330, as in the first embodiment (second example). A duct 610 is provided in the space to be formed. Further, as in the second embodiment (first example), transfer, development, charging, and the like are further performed on the duct 610 on the marking unit 32 (especially transfer unit 330) side. As an example of a sheet heat countermeasure means for improving the temperature rise problem due to sheet heat in each unit, a long second duct 620 that functions to insulate heat from the sheet is provided.

  Also in this case, the duct 620 is arranged on the near side and the depth side of the paper surface, similarly to the duct 610. That is, it is arranged so as to be substantially orthogonal to the paper conveyance direction of the paper reversal conveyance path 364.

  In addition, the image output unit 30 of the second embodiment (second example) is provided at one or both ends of the added long duct 620 as in the second embodiment (first example). If necessary, a fan 640 is provided as a forced convection means for positively forming an air flow in the duct 620 and acting a heat insulating function.

  As in the second embodiment (first example), when the fan 630 is provided for the duct 610 described in the first embodiment, one fan may serve as the fans 630 and 640. .

  The arrangement of the fan 640 (or 650) in the relationship between the duct 620 and the paper reversing conveyance path 364 is such that the recursive conveyance path forming member 512 is replaced with a paper reversing conveyance path 364 as shown in parentheses in FIG. It is the same. The functions and effects of the sheet reversing conveyance path 364, the duct 620, and the fan 640 (or 650) of the sheet reversing mechanism 360 are the same as those in the second embodiment (first example), and thus detailed description thereof is omitted here. To do.

<Third embodiment; double-sided conveyance path>
FIG. 8 is a side sectional view showing a first example of the third embodiment of a detailed configuration example of the image output unit 30 of the image output terminal 1. The image output unit 30 of the third embodiment (first example) is configured to include a double-sided conveyance path 510 as a recursive conveyance path for conveying printed paper in the double-sided copying unit 34, in the second embodiment (first example). It is characterized in that the duct 610 provided in the above is removed and only the duct 622 corresponding to the duct 620 is disposed only for the purpose of heat insulation. However, in this case, the duct 622 is an example of an air guide path.

  In addition, the image output unit 30 of the third embodiment (first example) actively causes the flow of air into the duct 622 at one or both ends of the long duct 622 as necessary. A fan 642 is provided as a forced convection means that is formed in a manner to allow the heat radiation function and the heat insulation function to act (refer to FIG. 9 to be described later in detail).

  Here, “if necessary” means that the air in the fan 642 heated by the heat from the paper is exhausted by the fan 642 as a forced convection device, so that the paper heat of each unit such as transfer, development, and charging It means the case where the purpose is to enhance the effect of paper heat countermeasures to improve the problem of temperature rise due to.

<Fan Arrangement Example; Third Embodiment>
FIG. 9 is a diagram illustrating an arrangement example of the fans 642 in relation to the air guide path (duct 622) and the recursive conveyance path. In FIG. 9, not only the relationship with the recursive conveyance path forming member 512 as the recursive conveyance path, but also the paper reversal conveyance path 364 of the paper reversal mechanism 360 used in a third embodiment (second example) described later. The relationship is also shown in parentheses.

  The duct 622 forms a cavity in each wall surface constituting the duct 622. As shown in FIG. 9A, the duct 622 has an upper surface on the marking unit 32 side, side surfaces on both sides, and a lower surface on the duct 610 side, respectively. Wall surfaces 622a, 622b, 622c, and 622d are provided. That is, a wall surface 622d is also provided on the plate-like member 514 side constituting the recursive conveyance path forming member 512, and the duct 622 itself has an air guide path having a generally tunnel type structure that can actively form an air flow. Try to form.

  It is not necessary to provide the opening 516 in the plate member 514. Further, the duct 622 does not need to be in close contact with the plate member 514. These points are different from the corresponding first embodiment (first example) and second embodiment (first example).

  The duct 622 is disposed between the single-sided printed paper or the recurring conveyance path forming member 512 (specifically, the plate-like member 514) and the marking unit 32 (particularly the transfer unit 330), and heat is blocked by air inside the duct 622. By utilizing the effect, a heat insulating effect is prevented to prevent the heat of the single-sided printed paper or the plate-like member 514 (recursive conveyance path forming member 512) from being transmitted to the marking unit 32 side.

  For example, in the first arrangement example shown in FIG. 9B, a fan 642a for sucking outside air is placed at one end of the duct 622 (right opening 622e in the figure), and the air flowing through the duct 622 is Arranged upstream. In this case, the air sucked into the duct 622 by the fan 642a passes through the duct 622 and is further discharged from the other end of the duct 622 (left opening 622f in the drawing).

  On the other hand, in the second arrangement example shown in FIG. 9C, an air discharge fan 642b is placed at the other end of the duct 622 (the opening 622f on the left side in the figure), and the air flowing through the duct 622 is It is arranged downstream. In this case, outside air is sucked into the duct 622 from the end opposite to the end where the fan 642b is provided (the opening 622e on the right side in the figure), passes through the duct 622, and is further discharged by the fan 630b.

  Further, as in the third arrangement example shown in FIG. 9D, the first arrangement example shown in FIG. 9B and the second arrangement example shown in FIG. A configuration in which a fan 642a for sucking outside air is provided at one end (right opening 622e in the drawing) and a fan 642b for discharging air is provided at the other end (left opening 622f in the drawing) of the duct 622. It is good.

  In any of the first arrangement example shown in FIG. 9B, the second arrangement example shown in FIG. 9C, and the third arrangement example shown in FIG. 9D, the fans 642a and 642b are forced. The sucked outside air is caused to flow into the duct 622, that is, the cooling air is caused to flow in a direction perpendicular to the paper transport direction. The heat blocking effect of the air itself in the duct 622 prevents the heat of the single-side printed paper and the plate-like member 514 (recursive transport path forming member 512) transmitted to the duct 622 side from being transmitted to the marking unit 32 side. .

  In this example, the fan 642 is provided. However, the fan 642 is provided in order to cut off the heat from the single-side printed paper and the plate-like member 514 by using heat discharge by the air flow in the duct 622. That is not essential.

  The duct 622 is provided with openings 622e and 622f at both ends of the elongated shape. This is because even if the openings 622e and 622f are provided, the air naturally flows in the duct 622, and a heat insulating action by heat discharge can be obtained.

  In addition, it is not essential to provide the openings 622e and 622f at the end of the duct 622, and a wall surface may be used. This is because heat insulation can be obtained by the air in the duct 622. However, in this case, the internal temperature rises due to the heat insulation action, and the effect is reduced.

<Third embodiment; paper reversing conveyance path>
FIG. 10 is a side sectional view showing a second example of the third embodiment of the detailed configuration example of the image output unit 30 of the image output terminal 1. The image output unit 30 of the third embodiment (second example) replaces the double-sided conveyance path 510 in the third embodiment (first example) as a recursive conveyance path through which the printed paper in the double-sided copying unit 34 is conveyed. The sheet reversing conveyance path 364 is characterized in that it is provided directly below the marking unit 32. This point is the same as in the first embodiment (second example) and the second embodiment (second example).

  On the premise of such a configuration, the image output unit 30 of the third embodiment (second example) is provided in the second embodiment (second example) similarly to the third embodiment (first example). This is characterized in that the duct 610 is removed and only the duct 622 is disposed for the purpose of heat insulation only. The air in the duct 622 is configured to receive only a heat insulating effect that prevents the heat of the single-side printed paper and the recurring conveyance path forming member 512 from being transmitted to the marking unit 32 side.

  It is not necessary to provide the opening 366 in the sheet reverse conveyance path 364. Further, the duct 622 does not need to be in close contact with the sheet reverse conveyance path 364. These points are different from the corresponding first embodiment (second example) and second embodiment (second example).

  In addition, the image output unit 30 of the third embodiment (second example) is required at one or both ends of the long duct 622 as in the third embodiment (first example). Accordingly, a fan 642 is provided as a forced convection means for positively forming an air flow in the duct 622 and acting a heat insulating function.

  The arrangement of the fan 642 in relation to the duct 622 and the paper reversal conveyance path 364 is the same as that in which the recursive conveyance path forming member 512 is replaced with the paper reversal conveyance path 364 as shown in parentheses in FIG. Since the effects of the sheet reversing conveyance path 364, the duct 622, and the fan 642 of the sheet reversing mechanism 360 are the same as those in the third embodiment (first example), a detailed description is omitted here.

1 is a diagram illustrating an overall outline of an image output terminal having a function of an image forming apparatus according to the present invention. It is a sectional side view which shows 1st Embodiment (1st example) of the detailed structural example of the image output part of an image output terminal. In 1st Embodiment, it is a figure explaining the example of arrangement | positioning of the fan in the relationship with a 1st hollow member and a recursive conveyance path. It is a sectional side view which shows 1st Embodiment (2nd example) of the detailed structural example of the image output part of an image output terminal. It is a sectional side view which shows 2nd Embodiment (1st example) of the detailed structural example of the image output part of an image output terminal. In 2nd Embodiment, it is a figure explaining the example of arrangement | positioning of the fan in the relationship with a 2nd hollow member and a recursive conveyance path. It is a sectional side view which shows 2nd Embodiment (2nd example) of the detailed structural example of the image output part of an image output terminal. It is a sectional side view which shows 3rd Embodiment (1st example) of the detailed structural example of the image output part of an image output terminal. In 3rd Embodiment, it is a figure explaining the example of arrangement | positioning of the fan in the relationship with a 1st hollow member and a recursive conveyance path. It is a sectional side view which shows 3rd Embodiment (2nd example) of the detailed structural example of the image output part of an image output terminal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image output terminal, 10 ... Image reading part, 12 ... Document feeder, 15 ... User interface part, 20 ... Controller part, 24 ... Electrical board unit, 26 ... Board storage housing, 30 ... Image output part, 310 ... Photosensitive Body unit, 312 ... photosensitive drum, 314 ... charger, 316 ... writing scanning unit, 32 ... marking unit, 320 ... developing unit, 33 ... fixing unit, 330 ... transfer unit, 332 ... transfer section, 34 ... duplex copying Unit: 340: Cleaning unit, 350: Conveyance path switching unit, 352 ... Conveyance belt, 356 ... Switching lever, 358 ... Conveyance roller, 36 ... Discharge unit, 360 ... Paper reversing mechanism, 362 ... Paper guide unit, 364 ... Paper Reverse conveyance path, 366... Opening, 368... Transport roller, 370 .. refeed path, 378. DESCRIPTION OF SYMBOLS 0 ... Paper feed conveyance path, 412 ... Paper feed conveyance belt, 418 ... Conveyance roller, 510 ... Double-sided conveyance path, 512 ... Recursive conveyance path formation member, 514 ... Plate-shaped member, 516 ... Opening, 518 ... Conveyance roller, 520 ... Junction part, 610 ... Duct (first hollow member), 610d ... Opening part, 620 ... Duct (second hollow member), 620g ... Opening part, 622 ... Duct (first hollow member), 630, 640 , 642, 650... Fan, 80... Paper feed unit, 82.

Claims (8)

A recording unit for recording on a recording medium;
A heat treatment unit for processing an image recorded on the recording medium by the recording unit using heat;
A recursive conveyance path that is located below the recording unit in the vertical direction and recursively conveys the recording medium that has passed through the heat treatment unit to the recording unit;
An air guide path for guiding air, which is disposed between the recording unit and the recursive transport path and close to the recursive transport path;
A recording apparatus comprising: A first opening provided in a part of the recurring conveyance path facing the air guide path;
A second opening provided in a portion of the first air guide path facing the recursive conveyance path;
The recording apparatus according to claim 1, further comprising:   The recording apparatus according to claim 1, further comprising a first air flow generation unit configured to generate an air flow in the air guide path.   The recording apparatus according to claim 3, wherein the first air flow generation unit is configured to suck out air from the air guide path.   5. The recording according to claim 1, further comprising a hollow member that is disposed between the image forming unit and the first air guide path and in which a cavity is formed. apparatus.   6. The recording apparatus according to claim 5, further comprising second air flow generation means for generating an air flow in the hollow member.   The recording apparatus according to claim 6, wherein the first air flow generation unit also serves as the second air flow generation unit. The recording section is an image forming section having an image holding body for holding an image and a transfer section for transferring an image formed on the image holding body to a recording medium,
8. The heat treatment unit according to claim 1, wherein the heat treatment unit is a fixing unit that fixes an image transferred to the recording medium by the transfer unit to the recording medium using heat. 9. The image forming apparatus described.