JP2009234751A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain an image defect generated by damaging a surface of a fixing member due to burr remaining at an edge or the like of a recording paper in an image forming apparatus using an electrophotography system. <P>SOLUTION: The image forming apparatus includes a toner image forming part, a transferring part, a burr reforming device 70 for reforming burr at an edge of a recording paper supplied to the transferring part, and a fixing part for fixing a toner image on the recording paper whose burr is reformed. The burr reforming device 70 has a burr reforming roll 71 provided with a spiral protrusion 713 on its surface, and a pressurizing roll 72 pressurizing the burr reforming roll 71. After the edge of the recording paper reaches an opposed part Q of the burr reforming roll 71 and the pressurizing roll 72, the edge of the recording paper is sequentially pressurized by a spiral protrusion 713 of the rotating burr reforming roll 71. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus such as a copying machine or a printer using an electrophotographic system.

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic copying machine or printer, a toner image transferred onto a recording medium such as recording paper is fixed by a thermal pressure fixing method.
In this case, normally, a latent image formed on a predetermined photoconductor is visualized as a toner image by a developing unit, and a recording sheet that has been waiting on a resist roll in time with this image is conveyed, and a predetermined transfer is performed. The image is transferred onto the recording paper by the means, and then the image is fixed on the recording paper by pressure and heat fixing.

In this case, if there is a burr at the end of the recording paper, for example, the recording paper standby position on the registration roll may vary, which may cause variations in the image printing position on the recording paper.
To deal with such a problem, Patent Document 1 describes an image forming apparatus in which a burr correcting unit that corrects a burr at the end of a recording sheet is provided between a paper feeding unit and a registration roll. The burr correcting means is arranged so that fine irregularities are formed on the surface of the roll along the feeding direction of the recording paper, and the positions of the irregularities on the roll pair are alternately shifted so as to engage with each other, thereby removing the burr at the leading edge of the recording paper. The crushing method is adopted.

Japanese Patent Laid-Open No. 10-218459

  By the way, in recent years, in a fixing device that employs a thermal pressure fixing method, the surface layer of the fixing member may be formed using a fluororesin in order to impart high releasability to the surface of the fixing member. Since the surface layer of the fluororesin has a relatively low hardness, it is easily damaged by the recording paper edge and paper width edge supplied to the nip portion. In particular, there may be a case where scars and streaks generated on the surface of the fixing member due to burrs existing at the edge of the recording paper are transferred to the image surface after fixing, resulting in an image defect.

  The present invention has been made to solve such problems. In other words, an object of the present invention is to provide an image forming apparatus using an electrophotographic system in which burrs are present at the leading edge of a recording sheet on which an image is fixed, and image defects caused by scratching the surface of the fixing member. It is to suppress.

Therefore, in the present invention, a method is adopted in which a spiral roll having a spiral convex portion formed on the roll surface and a straight roll are combined, and the leading edge of the recording paper is passed through the opposed portions of these roll pairs. Thus, according to the present invention, an image forming apparatus according to claims 1 to 7 is provided.
The invention according to claim 1 is a toner image forming unit that forms a toner image, a transfer unit that transfers a toner image formed by the toner image forming unit onto a recording sheet, and a recording sheet that is supplied to the transfer unit A burr correcting unit that corrects the burr at the tip of the recording medium, and a fixing unit that fixes the toner image transferred by the transfer unit onto the recording paper on which the burr at the tip is corrected by the burr correcting unit. The burr correcting means includes a burr correcting roll having a spiral convex portion that is rotationally driven and arranged adjacent to the roll surface at a predetermined interval, and a burr correcting roll that rotates while pressing the burr correcting roll. A pressure roll on which no convex portion is formed, and the burr straightening roll is formed after a leading end of a recording sheet fed to a facing part between the burr straightening roll and the pressure roll reaches the facing part. ,in front An image forming apparatus characterized by sequentially pressing the leading end of the recording sheet by the spiral protrusions.

The invention according to claim 2 is such that the burr correcting roll of the burr correcting means rotates at a speed faster than the feeding speed of the recording paper fed to the opposite part of the burr correcting roll and the pressure roll. The image forming apparatus according to claim 1.
According to a third aspect of the present invention, the burr correcting roll of the burr correcting unit is configured such that the leading edge of a recording sheet fed to a facing portion between the burr correcting roll and the pressure roll reaches the facing portion. The spiral convex portion rotates so as to contact the entire width direction of the recording paper while moving a length corresponding to a region on the recording paper where the toner image is not formed. Item 3. The image forming apparatus according to Item 1 or 2.

The invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3, wherein the pressure roll of the burr correcting means is made of an elastic material.
According to a fifth aspect of the present invention, the pressure roll of the burr correcting means rotates at the same speed as the feeding speed of the recording paper fed to the opposite portion between the burr correcting roll and the pressure roll. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

  According to a sixth aspect of the present invention, the burr correcting means applies the addition to the burr correcting roll before the recording paper fed to the facing portion between the burr correcting roll and the pressure roll reaches the facing portion. 6. A contacting / separating means for contacting the pressure roll and separating the burr correction roll and the pressure roll after the leading edge of the recording paper reaches the facing portion. The image forming apparatus according to claim 1.

  According to a seventh aspect of the present invention, there is provided a toner image forming portion that forms a toner image, a transfer portion that transfers a toner image formed by the toner image forming portion onto a recording sheet, and before being supplied to the transfer portion. A burr correcting means for correcting the burr at the front end of the recording paper, and a fixing section for fixing the toner image transferred by the transfer section onto the recording paper whose front burr has been corrected by the burr correcting means; The burr correcting means includes a burr correcting roll having a spiral-shaped convex portion that is driven to rotate and formed on the roll surface, a pressure roll that rotates while pressing the burr correcting roll, and the burr correcting roll. Detecting means for detecting the position of the recording paper fed to the facing portion between the pressure roll and the pressure roll, and the leading end of the recording paper fed to the facing portion between the burr correction roll and the pressure roll Reach the department The burr straightening roll is brought into contact with the burr straightening roll, and the burr straightening roll is separated from the pressure roll after the leading edge of the recording paper reaches the facing portion. An image forming apparatus characterized by the above.

  According to the first aspect of the present invention, by sequentially pressing the leading edge of the recording paper by the spiral convex portion of the burr correcting roll, it is possible to perform correction processing by applying extreme pressure to the burr portion at the leading edge of the recording paper. Further, image defects that occur because the surface of the fixing member is damaged by burrs remaining at the leading edge of the recording paper are suppressed.

  According to the second aspect of the present invention, extreme pressure is applied to the entire burr at the tip of the recording paper, and the correction effect is enhanced by rubbing the recording paper with the burr correcting roll.

  According to the third aspect of the present invention, it is possible to efficiently process the area where the burrs at the front end of the recording paper remain as compared with the case where this configuration is not provided.

  According to the invention which concerns on Claim 4, compared with the case where it does not have this structure, the adhesiveness of a pressure roll and a recording paper improves.

  According to the fifth aspect of the present invention, only the leading end portion of the recording paper is processed as compared with the case where this configuration is not provided.

  According to the sixth aspect of the present invention, compared to the case where the present configuration is not provided, the range in which there is a burr at the leading edge of the recording paper fed to the opposed portion between the burr correcting roll and the pressure roll. It can be processed.

  According to the seventh aspect of the present invention, it is possible to correct the burrs at the leading edge of the recording paper based on the position signal of the recording paper detected by the detecting means, as compared with the case where this configuration is not provided.

  Hereinafter, the best mode (embodiment) for carrying out the present invention will be described. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. Also, the drawings used are used to describe the present embodiment and do not represent the actual size.

First, a schematic configuration of the image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram of an image forming apparatus to which the exemplary embodiment is applied. Here, an intermediate transfer type image forming apparatus generally called a tandem type will be described as an example. The image forming apparatus shown in FIG. 1 includes a plurality of image forming units 1Y, 1M, 1C, and 1K that form toner images of respective color components by electrophotography as a toner image forming unit. Next, as the transfer unit, the primary transfer unit 10 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 15, and the intermediate transfer belt 15. A secondary transfer unit 20 that collectively transfers (secondary transfer) the transferred superimposed toner image onto a recording sheet P that is a recording material (recording sheet). Furthermore, a fixing device 60 that fixes the secondary transferred image on the recording paper P is provided as a fixing unit. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  As shown in FIG. 1, each of the image forming units 1Y, 1M, 1C, and 1K includes a photosensitive drum 11 that rotates in the direction of arrow A, a charger 12 that charges the photosensitive drum 11, and a photosensitive drum 11. A laser exposure device 13 for writing an electrostatic latent image (in FIG. 1, an exposure beam is indicated by a symbol Bm) and each color component toner is accommodated, and the electrostatic latent image on the photosensitive drum 11 is visualized with toner. And a developing unit 14. Further, a primary transfer roll 16 that transfers each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15 in the primary transfer unit 10, a drum cleaner 17 that removes residual toner on the photosensitive drum 11, and Have In the present embodiment, these image forming units 1Y, 1M, 1C, and 1K are arranged in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Arrange substantially linearly.

  The intermediate transfer belt 15 is circulated (rotated) at a predetermined speed in the direction B shown in FIG. 1 by various rolls. As various rolls, a drive roll 31 that rotates the intermediate transfer belt 15, a support roll 32 that supports the intermediate transfer belt 15, a tension roll 33 that applies a certain tension to the intermediate transfer belt 15 to prevent meandering, and a secondary roll A backup roll 25 provided in the transfer unit 20 and a cleaning backup roll 34 provided in a cleaning unit that scrapes residual toner on the intermediate transfer belt 15 are provided.

  The primary transfer unit 10 includes a primary transfer roll 16 that faces the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. A voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of the toner is applied to the primary transfer roll 16, and the toner images on the photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, A superimposed toner image is formed on the transfer belt 15.

The secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image carrying surface side of the intermediate transfer belt 15 and a backup roll 25. A backup roll 25 is disposed on the back side of the intermediate transfer belt 15 to serve as a counter electrode of the secondary transfer roll 22, and a metal power supply roll 26 to which a secondary transfer bias is stably applied is disposed in contact.
The secondary transfer roll 22 is placed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween, and further, the secondary transfer roll 22 is grounded to form a secondary transfer bias between the secondary transfer roll 22 and the secondary transfer section. The toner image is secondarily transferred onto the recording paper P transported to 20.

  An intermediate transfer belt cleaner 35 for removing residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer is provided on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15 so as to be able to contact and separate. A reference sensor (home position sensor) 42 that generates a reference signal for taking an image forming timing in each of the image forming units 1Y, 1M, 1C, and 1K is disposed upstream of the yellow image forming unit 1Y. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C and 1K start image formation.

In the present embodiment, as a recording paper transport system, a recording paper tray 50 that accommodates the recording paper P, a pickup roll 51 that takes out and transports the recording paper P in the recording paper tray 50, and a transport that transports the recording paper P. A roll 52, a conveyance chute 53 that sends the recording paper P to the secondary transfer unit 20, a conveyance belt 55 that conveys the recording paper P secondarily transferred by the secondary transfer roll 22 to the fixing device 60, and a recording paper A fixing inlet guide 56 for guiding P to the fixing device 60.
Furthermore, in the present embodiment, a burr correcting device that corrects burrs remaining at the front end of the recording paper P in front of the secondary transfer roll 22 at a predetermined position between the transport roll 52 and the secondary transfer roll 22. 70 is provided. The burr correcting device 70 will be described later.

Next, a basic image forming process of the image forming apparatus will be described.
In the image forming apparatus shown in FIG. 1, an image processing apparatus (IPS) (FIG. 1) is added to image data output from an image reading apparatus (IIT) (not shown), a personal computer (PC) (not shown), or the like. The image forming operation is executed by the image forming units 1Y, 1M, 1C, and 1K. In the IPS, input image data is subjected to predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing. The image data subjected to the image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates, for example, an exposure beam Bm emitted from a semiconductor laser to the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. After the surfaces of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are charged by the charger 12, the surfaces are scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent image is developed as a toner image of each color of Y, M, C, and K by each of the image forming units 1Y, 1M, 1C, and 1K.

  Next, the toner image formed on the photosensitive drum 11 is transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photosensitive drums 11 and the intermediate transfer belt 15 come into contact with each other. Specifically, in the primary transfer unit 10, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of toner is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, The image is sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

  After the toner image is sequentially primary-transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves to convey the toner image to the secondary transfer unit 20. The recording paper transport system rotates the pickup roll 51 in accordance with the timing of transporting the toner image to the secondary transfer unit 20 and supplies the recording paper P of a predetermined size from the recording paper tray 50. The recording paper P supplied by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport chute 53. Before reaching the secondary transfer unit 20, the recording paper P is temporarily stopped, and a registration roll (not shown) is rotated in accordance with the movement timing of the intermediate transfer belt 15 carrying the toner image. The position and the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the recording paper P is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (minus polarity) is applied from the power supply roll 26, and a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Then, the unfixed toner image carried on the intermediate transfer belt 15 is pressed at the secondary transfer unit 20 by the secondary transfer roll 22 and the backup roll 25, and electrostatically transferred onto the recording paper P at once.

Thereafter, the recording sheet P electrostatically transferred with the toner image is peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22 and conveyed as it is, to the conveyance belt 55 provided on the downstream side of the secondary transfer roll 22 in the recording sheet conveyance direction. And carry. The conveyance belt 55 conveys the recording paper P to the fixing device 60. The fixing device 60 processes the unfixed toner image on the recording paper P with heat and pressure and fixes it on the recording paper P. The recording paper P on which the fixed image is formed is conveyed to a paper discharge placement unit provided in a discharge unit of the image forming apparatus.
On the other hand, after the transfer to the recording paper P is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and the cleaning backup roll 34 and the intermediate transfer belt cleaner are transferred. It is removed from the intermediate transfer belt 15 by 35.

Next, the burr correcting device 70 will be described.
FIG. 2 is a diagram for explaining the burr correcting device 70 in the present embodiment. As shown in FIG. 2, the burr correction device 70 is composed of a pair of rolls, and has a burr having a spiral convex portion (spiral convex portion 713) that is rotated on a roll surface by a predetermined driving device (not shown). The straightening roll 71 includes a pressure roll 72 that is a straight roll that rotates while pressing the burr straightening roll 71 and does not have a spiral convex portion on the roll surface.
The burr straightening device 70 employs a roll pair configuration of a burr straightening roll 71 having a spiral convex portion 713 and a pressure roll 72 that is a straight roll, so that the burr straightening roll 71 and the pressure roll 72 are opposed to each other. An extreme pressure is applied to the burrs remaining at the leading end of the recording paper P fed to Q to correct the burrs.

  In the present embodiment, the burr correcting roll 71 is composed of a roll body 711 formed integrally with a metal such as aluminum and a roll shaft 712 made of a predetermined metal. Note that the roll body 711 of the burr correction roll 71 may be molded using a synthetic resin or the like adjusted to a predetermined hardness.

  As shown in FIG. 2, the spiral convex portion 713 of the burr straightening roll 71 is inclined so as to have a predetermined angle with respect to the roll shaft 712 of the burr straightening roll 71, and is arranged in a spiral shape over the entire roll surface. Yes. In the present embodiment, the height d of the spiral convex portion 713 is formed to be in the range of 100.2% to 110% with respect to the roll diameter R of the burr correction roll 71.

  As shown in FIG. 2, in the present embodiment, the spiral pitch T of the spiral convex portion 713 formed on the roll surface of the burr straightening roll 71 is 10% to 100% with respect to the roll diameter R of the burr straightening roll 71. % Range. Here, the spiral pitch T is the length in the major axis direction of the roll body 711 between the adjacent spiral protrusions 713. If the spiral pitch T is too short, the paper tends to be deformed. If the spiral pitch T is excessively long, it is necessary to increase the number of rotations of the burr correction roll 71 (to increase the rotation speed).

  In this embodiment, the roll diameter R of the burr correction roll 71 is usually in the range of 20 mm to 50 mm. Further, the length L in the major axis direction of the burr correcting roll 71 is usually in the range of 300 mm to 360 mm when the paper width is A4 lateral feed.

In the present embodiment, the pressure roll 72 includes a roll body 721 that is integrally formed of an elastic material, and a predetermined metal roll shaft 722. Since the roll body 721 is formed of an elastic material, the adhesion between the pressure roll 72 and the recording paper P (see FIG. 1) is enhanced. Examples of such an elastic material include silicon rubber and ethylene-propylene-diene rubber (EPDM).
As shown in FIG. 2, in the present embodiment, the pressure roll 72 is a straight roll that does not have a spiral convex portion on the roll surface of the roll body 721. By combining the metal burr straightening roll 71 having the spiral convex part 713 described above and the pressure roll 72 made of an elastic material having no spiral convex part on the roll surface, the burr straightening roll 71 and the pressurizing roll 71 are added. It becomes possible to apply an extreme pressure to the tip of the recording paper P (see FIG. 1) fed to the portion Q facing the pressure roll 72.
The roll diameter of the pressure roll 72 is usually in the range of 20 mm to 50 mm. Further, the length in the major axis direction of the pressure roll 72 is usually in the range of 300 mm to 360 mm when the paper width is A4 lateral feed.

Next, the burr correction process by the burr correction device 70 will be described.
FIG. 3 is a diagram for explaining a process for correcting the burr at the leading edge of the recording paper P by the burr correcting device 70. As shown in FIG. 3 (a), the recording roll P including a pair of rolls rotates in the direction of the arrow D and the direction of the arrow E, respectively, so that the recording paper P with the burrs C remaining at the tip is transported. The paper is fed to a facing portion Q between the burr correction roll 71 and the pressure roll 72 in the apparatus 70. At this time, the position of the conveyed recording paper P is detected by a sensor (detecting means) 73 disposed in front of the burr correcting device 70.

Next, as shown in FIG. 3B, when the position of the recording paper P is detected by the sensor 73, the pressure roll 72 is moved in the direction of arrow H by an unshown contact / separation device, and the burr correction roll 71 is moved. The pressure roll 72 comes into contact. At this time, the leading end portion of the recording paper P fed to the facing portion Q is pressed with a certain width in the paper feeding direction by a pressure roll 72 made of an elastic material.
In the present embodiment, the pressure roll 72 normally presses the burr correction roll 71 with a load of about 50 kgf. At the same time, the burr correction roll 71 is rotated in the direction of arrow F by a driving device (not shown), and the pressure roll 72 is driven to rotate in the direction of arrow G as the burr correction roll 71 rotates.
At this time, the spiral protrusion 713 (see FIG. 2) of the burr correcting roll 71 rotates while contacting the recording paper P, whereby the burr C at the front end of the recording paper P is corrected.

Subsequently, as shown in FIG. 3C, when the leading end of the recording paper P moves the opposing portion Q by a predetermined length, the pressing roll 72 is moved in the direction of arrow I by the contact / separation means (not shown), The correction roll 71 and the pressure roll 72 are separated from each other. At the same time, the rotation of the burr correction roll 71 and the pressure roll 72 is stopped, and the recording paper P is conveyed to the secondary transfer unit 20 (see FIG. 1) by the conveyance roll 52.
In the present embodiment, after the leading end of the recording paper P is inserted into the facing portion Q between the burr correction roll 71 and the pressure roll 72, the toner image on the recording paper P is not formed in the transport direction. When the length corresponding to the area is moved, the burr correcting roll 71 and the pressure roll 72 are separated from each other.
Specifically, the length corresponding to the area where the toner image is not formed on the recording paper P is 2 mm from the front end of the recording paper P, preferably about 1 mm. Thereby, the area | region where the burr | flash of the front-end | tip part of the recording paper P remains is corrected effectively.

In the present embodiment, the burr correcting roll 71 has a roll main body 711 (while the front end of the recording paper P fed to the facing portion Q between the burr correcting roll 71 and the pressure roll 72 passes through the facing portion Q. The spiral projection 713 formed on the roll surface of FIG. 2) rotates while pressing the recording paper P.
At this time, the portion of the convex portion arranged in a range corresponding to the length between the adjacent convex portions of the spiral convex portion 713 (spiral pitch T (see FIG. 2)) is brought into contact with the leading end portion of the recording paper P. It is preferable to rotate at least once. As a result, an extreme pressure can be applied over the entire leading edge of the recording paper P, and the entire burr C present at the leading edge of the recording paper P is corrected.

In the present embodiment, the burr correcting roll 71 can rotate at a speed faster than the feeding speed of the recording paper P fed to the opposed portion Q between the burr correcting roll 71 and the pressure roll 72 by the transport roll 52. preferable. At this time, the pressure roll 72 preferably rotates at the same speed as the paper feed speed (paper travel speed) of the recording paper P fed to the facing portion Q.
Thus, in the present embodiment, the entire burr C remaining at the front end of the recording paper P is corrected by providing a speed difference between the rotation speed of the burr correction roll 71 and the rotation speed of the pressure roll 72. Is possible. At this time, the rotational speed (V ₂ ) of the burr correcting roll 71 is determined by the size of the spiral pitch T (see FIG. 2) of the spiral convex portion 713 (see FIG. 2) formed on the roll surface. According to the relational expression
T ≦ (2 × V ₂ sin θ) / (V ₁ cos θ)
In the above relational expression, T is the spiral pitch, V ₁ is the sheet running speed, V ₂ is the rotational speed of the burr correcting roll 71, and θ is the spiral angle.
Moreover, in this Embodiment, the rotational speed of the burr | flash correction | amendment roll 71 becomes 1.2 times-5 times normally the pressure roll 72 rotational speed, Preferably it becomes 2 times.

  Further, in the present embodiment, the burr correcting roll 71 has a spiral convex portion while the tip of the recording paper P fed to the facing portion Q between the burr correcting roll 71 and the pressure roll 72 passes through the facing portion Q. It is preferable that the contact portion of 713 (see FIG. 2) with the recording paper P rotates at least once at high speed. As a result, the tip portion of the recording paper P where the burrs C remain is corrected throughout, and the possibility that the uneven shape remains in other portions of the recording paper P is eliminated.

Next, the contacting / separating means for contacting and separating the burr correcting roll 71 and the pressure roll 72 will be described.
FIG. 4 is a diagram illustrating an example of a mechanism for moving the roll pair of the burr correcting device 70 toward and away from each other. The contact / separation device 80 shown in FIG. 4 operates based on a signal obtained by detecting the position of the recording paper P fed to the facing portion Q between the burr correction roll 71 and the pressure roll 72 by the sensor 73 (see FIG. 3). A solenoid 81, a blanket 83 that holds the roll shaft of the pressure roll 72 with a shaft 82 fixed to the main body of the image forming apparatus (not shown) as a rocking center, and the solenoid 81 and the blanket 83 are connected to each other to press the blanket 83. A tension spring 84 for applying a tensile force for bringing the roll 72 into contact with the burr correcting roll 71 and a main body of the image forming apparatus (not shown) and the blanket 83 are connected, and the pressure roll 72 is separated from the burr correcting roll 71 to the blanket 83. And a tension spring 85 that imparts a tension force for the purpose.

As shown in FIG. 4, when the recording paper P (see FIG. 3) is not fed to the facing portion Q between the burr correcting roll 71 and the pressure roll 72, the main body of the image forming apparatus and the blanket 83 (not shown) are usually provided. The pressure roll 72 is separated from the burr correction roll 71 by the tensile force of the tension spring 85 connecting the two.
Next, when the position of the recording paper P fed to the facing portion Q between the burr correcting roll 71 and the pressure roll 72 is detected by the sensor 73 (see FIG. 3), the solenoid 81 is activated based on the detected signal. The blanket 83 is pulled up by a tension spring 84 that operates and connects the solenoid 81 and the blanket 83, the pressure roll 72 comes into contact with the burr correction roll 71, and the pressure roll 72 is pressed by a predetermined load. Yes. As described above, in this embodiment, the pressure roll 72 presses the burr correction roll 71 with a load of about 50 kgf.

1 is a schematic configuration diagram of an image forming apparatus to which the exemplary embodiment is applied. It is a figure explaining the burr correction apparatus in this Embodiment. It is a figure explaining the process which corrects the burr | flash of the front-end | tip of a recording paper with a burr correction apparatus. It is a figure explaining an example of the mechanism which makes a roll pair of a burr correction device contact / separate.

Explanation of symbols

1Y, 1M, 1C, 1K ... image forming unit, 11 ... photosensitive drum, 12 ... charger, 13 ... laser exposure device, 14 ... developer, 15 ... intermediate transfer belt, 16 ... primary transfer roll, 17 ... drum cleaner , 20 ... secondary transfer part, 60 ... fixing device, 70 ... burr correction device, 71 ... burr correction roll, 72 ... pressure roll, 73 ... sensor, 80 ... contact / separation device, 713 ... spiral convex part

Claims (7)

A toner image forming unit for forming a toner image;
A transfer unit that transfers the toner image formed by the toner image forming unit onto a recording sheet;
Burr correction means for correcting burr at the front end of the recording paper supplied to the transfer unit;
A fixing unit that fixes the toner image transferred by the transfer unit on the recording paper whose tip burr has been corrected by the burr correcting unit;
The burr correcting means is
A burr correction roll having a spiral-shaped convex portion that is rotationally driven and arranged adjacent to the roll surface at a predetermined interval;
A pressure roll that rotates while pressing the burr correction roll and is not formed with a spiral convex part,
The burr correcting roll is configured such that after the leading edge of the recording paper fed to the facing portion between the burr correcting roll and the pressure roll reaches the facing portion, the leading edge of the recording paper is sequentially moved by the spiral convex portion. An image forming apparatus characterized by pressing.   2. The burr correcting roll of the burr correcting means rotates at a speed faster than a feeding speed of a recording sheet fed to a facing portion between the burr correcting roll and the pressure roll. The image forming apparatus described.   The burr correcting roll of the burr correcting unit is configured such that a toner image on the recording sheet is fed after a leading edge of a recording sheet fed to a facing portion between the burr correcting roll and the pressure roll reaches the facing portion. 3. The image according to claim 1, wherein the spiral convex portion rotates so as to contact the entire width direction of the recording paper while moving a length corresponding to a region where no image is formed. Forming equipment.   The image forming apparatus according to claim 1, wherein the pressure roll of the burr correcting unit is made of an elastic material.   2. The pressure roll of the burr correcting means rotates at the same speed as a paper feeding speed of a recording paper fed to a facing portion between the burr correcting roll and the pressure roll. 5. The image forming apparatus according to any one of 4 above.   The burr correcting means brings the pressure roll into contact with the burr correcting roll before the recording paper fed to the facing portion between the burr correcting roll and the pressure roll reaches the facing portion, and 6. The image according to claim 1, further comprising contact / separation means for separating the burr correction roll and the pressure roll after the leading edge of the recording paper reaches the facing portion. Forming equipment. A toner image forming unit for forming a toner image;
A transfer unit that transfers the toner image formed by the toner image forming unit onto a recording sheet;
Burr correcting means for correcting burr at the front end of the recording paper before being supplied to the transfer unit;
A fixing unit that fixes the toner image transferred by the transfer unit on the recording paper whose tip burr has been corrected by the burr correcting unit;
The burr correcting means is
A burr correction roll having a spiral-shaped convex portion that is rotationally driven and formed on the roll surface;
A pressure roll that rotates while pressing the burr correction roll;
Detecting means for detecting a position of a recording sheet fed to a facing portion between the burr correcting roll and the pressure roll;
The pressure roll is brought into contact with the burr correction roll before the front end of the recording paper fed to the facing portion between the burr correcting roll and the pressure roll reaches the facing portion, and the front end of the recording paper An image forming apparatus comprising: a contact / separation unit that separates the burr correction roll and the pressure roll after the ink reaches the facing portion.

Images