JP2005089079A - Curl correcting device of recording medium and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curl correcting device and an image forming device having little influence of cooling air on a recording medium. <P>SOLUTION: This curl correcting device is provided at a rear stage of a fixing means of the image forming device to correct curl of a recording paper sheet 1 after fixing images. The device is provided with curl correcting rollers 11 to curve the recording medium, a blowing device 2 for blowing and cooling the surfaces of the curl correcting rollers 11 and a guide duct 15 for straightening cooling air from the blowing device 2 in an air direction for changing a course in a direction hitting on a tip of the recording medium entering between the curl correcting rollers 11 to enter among the curl correcting roller 11 and butting rollers 12 and 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic or electrophotographic recording medium curl correction apparatus and an image forming apparatus, and more particularly to a recording medium curl correction apparatus and an image forming apparatus for correcting curling of a recording medium after image fixing. It is.

  As a color image forming apparatus 100 such as a copying machine or a printer, as shown in FIG. 3, an apparatus adopting a diagram electrophotographic recording system is widely used. This is because the latent image formed on the image carrier scanned by the reading unit 110 is developed by the image forming apparatus 120 to form a visible image (toner image formation), and the visible image is recorded on a recording medium (recording paper). The image is transferred by electrostatic force, and then the transfer image is fixed on the recording paper by the fixing device 130 by heat.

  In other words, in FIG. 3, the image forming apparatus 120 is disposed substantially at the center of the color image forming apparatus 100, and the paper feeding unit 150 is disposed immediately below the image forming apparatus 120. The paper feed unit 150 includes a paper feed cassette 151 at each stage. Another sheet feeder 152 can be added as necessary. Above the image forming apparatus 120, a reading unit 110 that reads a document is disposed. A discharge storage unit 201 is formed on the left side of the image forming apparatus 120, and an image-formed recording medium (hereinafter referred to as a recording sheet) is discharged and stored.

  In the image forming apparatus 120, an image forming unit 122 for four colors (yellow (Y), cyan (C), magenta (M), and black (BK)) is arranged around a belt-shaped intermediate transfer belt 121. Yes. In each of the image forming units 122, a charging device 162 that performs charging processing on the surface of the photosensitive member around the drum-shaped photosensitive member 161, an exposure device 170 that irradiates the photosensitive member surface with image information with laser light, and a photosensitive member. A developing device 163 that visualizes the electrostatic latent image formed by exposure on the surface of the toner and a cleaning device 164 that removes and collects toner remaining on the photoreceptor are disposed.

  First, yellow (Y) toner is developed and transferred to the intermediate transfer belt in the yellow (Y) image forming section. Next, the magenta (M) image forming unit develops the magenta toner and transfers it to the intermediate transfer belt. Next, in the cyan (C) image forming section, cyan toner is developed and transferred to the intermediate transfer belt, and finally, black (BK) toner is developed and transferred to the intermediate transfer belt.

  In this example, a transfer device 151 that transfers the four color toner images developed on the intermediate transfer belt 121 to a sheet, and an intermediate transfer cleaning device 152 that removes and collects toner remaining on the surface of the intermediate transfer belt after transfer, respectively. Is arranged.

  A fixing device 130 for fixing the toner on the recording paper from which the toner image has been obtained is disposed downstream of the image forming apparatus (downstream in the paper conveyance path). The paper that has passed through the fixing device is stored in the paper discharge storage unit 201 by the paper discharge roller 200.

  At the time of double-sided printing, the paper is branched by the guide claw 192 of the branching unit 190, the paper is reversed via the double-sided device 191, the paper skew is corrected by the registration roller 213, and the back side image forming operation is performed.

  In the paper feeding unit 150, unused paper is stored in the paper feeding cassette 151, and the bottom plate that is rotatably supported raises the uppermost paper to a position where the pickup roller can contact. Due to the rotation of the paper feed roller, the uppermost paper is fed out from the paper feed cassette and conveyed to the registration roller 213. The registration roller 213 is controlled so as to start rotation at a timing so that the conveyance of the paper is temporarily stopped and the positional relationship between the toner image on the surface of the photosensitive member and the leading edge of the paper becomes a predetermined position.

  In the reading unit 110, in order to perform reading scanning of a document (not shown) placed on the contact glass 111, a reading traveling body 112 including a document illumination light source and a mirror reciprocates. Image information scanned by the reading traveling body 112 is read as an image signal into the CCD 114 installed behind the lens 113.

  The read image signal is digitized and subjected to image processing. Based on the image-processed signal, an electrostatic latent image is formed on the surface of the photoreceptor 161 by light emission of a laser diode LD (not shown) in the exposure apparatus 170. The optical signal from the LD reaches the photosensitive member via a known polygon mirror or lens. An automatic document feeder 180 that automatically feeds a document onto the contact glass 111 is mounted above the reading unit 110.

  The color image forming apparatus 100 of this example scans and reads a document as described above, digitizes it, and copies it onto a sheet of paper. In addition to the function as a so-called digital color copying machine, the image of the document is controlled by a control device (not shown). This is a multi-function image forming apparatus having a facsimile function for exchanging information with a remote place and a so-called printer function for printing image information handled by a computer on paper. All images formed by any function are discharged and stored in one discharge storage unit 201.

  During double-sided printing, the recording paper is branched by the guide claw 192, the recording paper is reversed via the double-sided device 191, discharged from the paper discharge roller 140 via the reverse paper discharge roller 193, and discharged from the paper discharge storage unit 201. Is stacked. In this case, the stacked recording sheets are in the state that the image surface is the bottom side, and when the processing order of the originals handled by copying, facsimile, and printer is printed from one page, it is taken out from the paper discharge storage section The first page is at the top, and there is no need to perform operations such as aligning the pages anew.

  In the color image forming apparatus 100, the toner image transferred to the recording paper in the fixing device 130 is fixed by pressing and heating using the fixing rollers 131 and 132. For this reason, a curl in which both ends in the conveyance direction are warped and the image surface side is concave may occur on the recording paper. The curl state is caused by various factors such as moisture in the recording medium, nip shape of the fixing roller, temperature, humidity, recording medium material, and toner amount. For this reason, a curl correction device 140 is provided to correct the curl of the recording paper after the image fixing and make it flat.

  Conventionally, there has been the following as a curl correcting device 140 for a recording medium. The curl correction device 140 is disposed downstream of the fixing device in the sheet conveying direction, and is configured by pressing the small diameter contact rollers 142 and 143 to the large diameter lower roller 141 as shown in FIG. ing. The lower roller 141 is formed of rubber or the like having a relatively high hardness, and is driven to rotate in the direction of the arrow in the drawing by a driving means (not shown). The contact rollers 142 and 143 are made of rubber or resin having a relatively low hardness, and are driven to rotate by being pressed against the lower roller 141. The recording paper 144, which is a recording medium, is curled when it is conveyed between the lower roller 141 and the abutting rollers 142, 143 so that the image surface side is convexly wound around the lower roller 141 and conveyed. It is.

  In FIG. 6, reference numerals 145 and 146 denote conveyance guides for guiding the recording sheet 144 after image fixing to the nip of the curl correction device 140, and are attached vertically to a side plate or the like (not shown). Further, a cross flow fan 146 as a blower is provided immediately above the lower roller 141 and the contact rollers 142 and 143. This cross flow fan 146 is used to promote the cooling and solidification of the toner by blowing the cooling air A onto the recording paper 144 at the same time as it is clamped between the lower roller 141 and the abutting rollers 142 and 143 to correct the curl. It is.

Reference numerals 147 and 148 denote guide ducts, which are attached to a side plate or the like (not shown). When the air is blown by the guide ducts 147 and 148 and the cross flow fan 146, the air is not leaked to the upstream side and the downstream side of the recording paper conveyance direction from the lower roller 141 except for the curl correction portion of the recording paper 144. It is. This is because when the wind leaks upstream, the cooling and solidification of the toner proceeds before curl correction, and the effect of reverse curling by the curl correction means is reduced. On the other hand, when the wind leaks downstream This is because the behavior of the sheet 116 affects the final curl amount (see, for example, Patent Document 1).
Japanese Patent No. 3001727

  By the way, the above-described curl correction device for a recording medium has a structure in which cooling air is directly applied to a recording sheet as a recording medium. Therefore, there is a problem that the curl correction device itself is not directly cooled and cooling efficiency is low. SUMMARY OF THE INVENTION An object of the present invention is to provide a curl straightening device having a high cooling efficiency with little influence of cooling air on a recording medium.

  The invention of claim 1 is provided at a stage subsequent to a fixing means for fixing the transferred image of an image forming apparatus that transfers and fixes a visible image formed on an image carrier in accordance with image information to a recording medium. A curl correction apparatus for correcting curling of a recording medium after image fixing includes a curl correction roller for curving the recording medium and a blower for cooling the surface of the curl correction roller by passing air through the curl correction roller. This is a curl correction apparatus for a recording medium.

  According to a second aspect of the present invention, there is provided the recording medium curl correcting apparatus according to the first aspect, wherein the curl correcting roller includes a plurality of rollers for sandwiching the recording medium, and cooling air from the blower is transmitted between the curl correcting rollers. A guide duct is provided that rectifies in the wind direction so as to change the course in the direction of entering the space between the plurality of correction rollers at the leading end of the recording medium that enters.

  According to a third aspect of the present invention, in the recording medium curl correction apparatus according to the first or second aspect, the correction roller includes an upper roller and a lower roller.

  According to a fourth aspect of the present invention, the recording medium curl correcting apparatus according to any one of the first to third aspects guides the recording medium to one of two recording medium paths that diverge the recording medium after the curl correcting roller. A guide claw is provided, and a guide duct is provided that rectifies the wind in the direction of the wind so that the cooling air from the blower device hits the tip of the recording medium guided by the guide claw and changes the course in the direction guided by the guide claw. It is what.

  According to a fifth aspect of the present invention, in the recording medium correcting apparatus according to the fourth aspect, the guide claw includes a ventilation hole portion through which the cooling air passes.

  According to a sixth aspect of the present invention, in the recording medium curl correcting apparatus according to the fourth or sixth aspect, the two branched paths are a recording medium discharge path and a duplex printing path, and the guide claw is the recording medium. Is guided to one of the passages.

  A seventh aspect of the present invention is an image forming apparatus comprising the recording medium curl correcting apparatus according to any one of the first to sixth aspects.

  According to the recording medium curl correction apparatus of the present invention, the cooling air directly cools the correction roller, so that the cooling efficiency of the correction roller is improved.

  Hereinafter, the best mode for carrying out the present invention will be described based on the embodiments described in the accompanying drawings.

  FIG. 1 is a side view showing an embodiment of a curl correcting apparatus for a recording medium according to the present invention, and FIG. 2 is a plan view of the curl correcting apparatus shown in FIG. In this example, the basic configuration of the applied image forming apparatus is the same as that of the conventional color image forming apparatus shown in FIG.

  The curl correcting device 10 is arranged on the downstream side in the sheet conveying direction from the fixing device 130 including the fixing rollers 131 and 132, the driving pulley 133, and the belt 134, and as shown in FIG. The contact rollers 12 and 13 having a small diameter are pressed against each other. The upper roller 11 is made of rubber having a relatively high hardness and is driven to rotate in the direction of the arrow in the figure by a driving means (not shown). The abutting rollers 12 and 13 are made of rubber or resin having a relatively low hardness and are driven to rotate by being pressed against the upper roller 11.

  The recording paper 1 that is a recording medium is curled when it is conveyed between the upper roller 11 and the contact rollers 12 and 13 and wrapped around the upper roller 11 so that the image surface side is concave. It is.

  In this example, a cross flow fan 2 is provided immediately above the upper roller 11 as a blower that is a cooling means. The cross flow fan 2 blows the cooling air B directly on the upper roller 11 to cool the upper roller.

  Reference numeral 15 denotes a cooling air guide duct, which is attached to a side plate (not shown). The guide duct 15 guides the cooling air B so that air is blown to the upper surface of the upper roller 11 and the recording paper leading edge 1a of the recording paper 1 conveyed from the fixing device 130 when blown by the cross flow fan 2. . The wind blown to the recording paper leading edge 1 a of the recording paper guides the recording paper 1 so that the recording paper 1 enters between the upper roller 11 and the contact rollers 12 and 13.

  According to this example, since the cooling air directly cools the upper roller 11 of the curl correction device 10, the cooling efficiency of the curl correction device 10 is improved and the recording paper 1 can be smoothly guided to the curl correction device 10. it can.

It is a side view which shows the 2nd Example of an apparatus. In this example, the curl correction device 20 includes an upper roller 21 and contact rollers 22 and 23 similar to those in the first embodiment, downstream of the fixing device 130 having the same configuration as that of the first embodiment. In this example, the shape of the guide duct 25 that guides the cooling air C is different from that of the first embodiment, and a branching portion 90 is provided downstream of the upper roller 21 and the contact rollers 22 and 23, and the paper path I (back surface transfer), The present embodiment is different from the first embodiment in that a guide claw 92 for sorting to the path II (paper discharge) is provided.

  In this example, 25 directs the cooling air C to 21 and guides the air C1 to the recording paper leading edge 1a of the recording paper 1 conveyed from the fixing device 130, and changes the course of the recording paper at the guide claw 92. Branches to wind C2 to help.

  In this example, the guide claw 92 has a comb-teeth shape in which ventilation grooves, which are ventilation holes through which cooling air passes, are continuously formed. For this reason, when the recording paper 1 is discharged from the upper roller 21 by the wind of the cross flow fan 2, the recording paper 1 at the guide claw 92 as shown by the arrow E in FIG. The tip of 1 is pushed down.

  For this reason, according to this example, the cooling efficiency can be improved as in the first embodiment, the recording paper 1 can be smoothly guided to the curl correction device 20, and jamming can be reduced.

  Note that the image forming apparatus of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

1 is a side view showing a first embodiment of a curl correcting apparatus for a recording medium according to the present invention. It is a top view which shows the curl correction apparatus of the recording medium shown in FIG. It is a side view which shows the 2nd Example of the curl correction apparatus of the recording medium based on this invention. 1 is a plan view showing an image forming apparatus to which a curl correcting apparatus for a recording medium according to the present invention is applied. FIG. 5 is an enlarged view of the image forming apparatus shown in FIG. 4 showing the arrangement of the curl correcting apparatus for a recording medium according to the present invention. It is a side view which shows the curl correction apparatus of the conventional recording medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording paper 1a Recording paper front-end | tip 2 Cross flow fan 10 Curl correction apparatus 11 Curl correction roller (upper roller)
12, 13 Abutting roller 15 Guide duct 20 Curl correction device 21, Upper rollers 22, 23 Abutting roller 25 Guide duct 41 Paper discharge roller 90 Branch portion 92 Guide claw

Claims (7)

An image forming apparatus for transferring and fixing a visible image formed on an image carrier in accordance with image information to a recording medium is provided at a stage subsequent to fixing means for fixing the transferred image. A curl correction apparatus for correcting curl, comprising: a curl correction roller for curving the recording medium; and a blower for cooling the curl correction roller by ventilating the surface thereof. 2. The curl correction apparatus for a recording medium according to claim 1, wherein the curl correction roller includes a plurality of rollers for sandwiching the recording medium, and the cooling air from the blower is applied to the front end of the recording medium that enters between the curl correction rollers. An apparatus for correcting curl of a recording medium, comprising a guide duct that rectifies in a wind direction that changes a course in a direction between a plurality of correction rollers. 3. The recording medium curl correction apparatus according to claim 2, wherein the correction roller includes an upper roller and a lower roller. 4. The curl correction device according to claim 1, wherein a guide claw that guides one of two recording medium paths for branching the recording medium is disposed behind the curl correction roller, and the air blowing is performed. An apparatus for correcting a recording medium, comprising: a guide duct that rectifies the cooling air from the apparatus at the leading end of the recording medium guided by the guide claws and changes the direction of the wind in the direction guided by the guide claws. 5. The recording medium correction apparatus according to claim 4, wherein the guide claw includes a ventilation hole portion through which the cooling air passes. 6. The recording medium curl correction apparatus according to claim 4, wherein the two branched paths are a recording medium discharge path and a double-sided printing path, and the guide claw passes through the recording medium. An apparatus for correcting curl of a recording medium, characterized in that: An image forming apparatus comprising the recording medium correcting device according to claim 1.

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