This application is based on Japanese Patent Application No. 2013-070182 filed with the Japan Patent Office on Mar. 28, 2013, the contents of which are hereby incorporated by reference.
The present disclosure relates to a curl correcting device for correcting a curl of a sheet and an image forming apparatus with the same.
Conventionally, a technology is known which can vertically invert a curl correcting device for correcting a curl of a sheet to deal with both an upward curl formed by an upwardly warped leading end part of a sheet and a downward curl formed by a downwardly warped leading end part of a sheet.
In the above curl correcting device, a curl of a sheet is corrected in a nip portion between a hard roller and an elastic roller. The hard roller and the elastic roller are supported in a rotatable rotation unit. In this case, there has been a problem that if a sheet, which is not curled, is carried into the nip portion, the sheet is rather curled.
The present disclosure was made to solve the above problem and aims to provide a curl correcting device which inhibits a sheet, which is not curled, from being curled when the sheet is carried in, and an image forming apparatus with the same.
A curl correcting device according to one aspect of the present disclosure is arranged to an apparatus main body which includes a sheet conveyance path through which a sheet is conveyed. The curl correcting device includes a first roller, a second roller, a supporting unit. The first roller includes a first rotary shaft and is rotated about the first rotary shaft and has elastically deformable property. The second roller includes a second rotary shaft parallel to the first rotary shaft, is rotated about the second rotary shaft and elastically deforms the first roller by being pressed against the first roller, thereby forming a curved nip portion between the first and second rollers. The supporting unit supports the first and second rollers rotatably about axes by rotatably supporting the first and second rotary shafts, includes a third rotary shaft arranged parallel to the first rotary shaft, and is supported in the casing rotatably about the third rotary shaft. The supporting unit includes a plurality of inner conveyance path inside configured to be a part of the sheet conveyance path. The plurality of inner conveyance path includes a first conveyance path which has the nip portion and a second conveyance path which does not have the nip portion. The second conveyance path intersects with the first conveyance path. The first conveyance path communicates with the sheet conveyance path by the supporting unit being arranged at a first position about the third rotary shaft. The second conveyance path communicates with the sheet conveyance path by the supporting unit being arranged at a second position about the third rotary shaft.
Further, an image forming apparatus according to another aspect of the present disclosure includes the above curl correcting device, an apparatus main body and an image forming section. The image forming section forms an image on a sheet.
These and other objects, features and advantages of the present disclosure will become more apparent upon reading the following detailed description along with the accompanying drawings.
Hereinafter, embodiments of the present disclosure are described in detail based on the drawings.
<Description of Image Forming Apparatus>
The image forming apparatus 1 includes an apparatus main body 10 having a substantially rectangular parallelepipedic housing structure and an automatic document feeder 20 arranged above the apparatus main body 10. A reading unit 25 for optically reading a document image to be copied, an image forming section 30 for forming a toner image on a sheet, a fixing unit 60 for fixing the toner image to the sheet, a sheet feeding unit 40 for storing fixed form sheets to be conveyed to the image forming section 30, a conveyance path 50 for conveying a fixed form sheet from the sheet feeding unit 40 or a manual sheet feeding unit 46 to a sheet discharge opening 10E by way of the image forming section 30 and the fixing unit 60, and a conveying unit 55 (intermediate conveying unit) including a sheet conveyance path constituting a part of the conveyance path 50 inside are housed in the apparatus main body 10.
The automatic document feeder (ADF) 20 is rotatably mounted on the upper surface of the apparatus main body 10 and automatically feeds a document sheet to be copied toward a predetermined document reading position.
The reading unit 25 optically reads an image of a document automatically fed from the ADF 20 or a manually placed document.
The image forming section 30 performs a process for forming a full-color toner image and transferring the toner image onto a sheet, and includes four image forming units 32Y, 32M, 32C and 32Bk arranged in a tandem manner and configured to form toner images of yellow (Y), magenta (M), cyan (C) and black (Bk), an intermediate transfer unit 33 arranged above and adjacent to the image forming unit 32, and a toner supply unit 34 arranged above the intermediate transfer unit 33.
Each of the image forming units 32Y, 32M, 32C, 32Bk includes a photoconductive drum 321, and a charger 322, an exposure device 323, a developing device 324, a primary transfer roller 325 and a cleaning device 326 arranged around this photoconductive drum 321.
The photoconductive drum 321 is rotated about its shaft and an electrostatic latent image and a toner image are formed on the peripheral surface thereof. The charger 322 uniformly charges the surface of the photoconductive drum 321. The exposure device 323 forms an electrostatic latent image by irradiating the peripheral surface of the photoconductive drum 321 with light based on image data of a document image. The developing device 324 supplies toner to the peripheral surface of the photoconductive drum 321 to develop the electrostatic latent image formed on the photoconductive drum 321. The primary transfer roller 325 primarily transfers the toner image on the photoconductive drum 321 to an intermediate transfer belt 331. The cleaning device 326 includes a cleaning blade and the like and cleans the peripheral surface of the photoconductive drum 321 after the transfer of the toner image.
The intermediate transfer unit 33 includes the intermediate transfer belt 331, a drive roller 332 and a driven roller 333. The intermediate transfer belt 331 is an endless belt mounted on the drive roller 332 and the driven roller 333 and toner images are transferred from a plurality of photoconductive drums 321 to the same position of the outer peripheral surface of the intermediate transfer belt 331 in a superimposing manner (primary transfer). A secondary transfer roller 35 (transfer unit) is arranged to face the peripheral surface of the drive roller 332. A full-color toner image superimposed on the intermediate transfer belt 331 is transferred to a sheet in a secondary transfer nip portion between the drive roller 332 and the secondary transfer roller 35.
The toner supply unit 34 includes a toner container for yellow 34Y, a toner container for magenta 34M, a toner container for cyan 34C and a toner container for black 34Bk and stores toner of each color. The toners of the respective colors are supplied to the developing devices 324 of the image forming units 32Y, 32M, 32C and 32Bk corresponding to the colors through unillustrated supply paths.
The sheet feeding unit 40 includes a first sheet cassette 40A and a second sheet cassette 40B arranged in two levels for storing fixed form sheets P out of sheets to which an image forming process is applied. These sheet cassettes can be pulled out forward from the front side of the apparatus main body 10. The first sheet cassette 40A includes a sheet storage portion 41A for storing a sheet stack formed by stacking the fixed form sheets. The uppermost sheet of the sheet stack in the sheet cassette 40A is fed one by one and carried into an upstream end of the conveyance path 50 by driving a pickup roller 43 and a feed roller 44. Note that the second sheet cassette 40B is configured similarly to the first sheet cassette 40A.
A manual feed tray 46 is arranged on a right surface 10R of the apparatus main body 10. A feed roller 461 is arranged near the manual feed tray 46. A lower end part of the manual feed tray 46 is so attached to the apparatus main body 10 that the manual feed tray 46 is openable and closable relative to the apparatus main body 10.
The conveyance path 50 includes a main conveyance path 50A for conveying a sheet P from the sheet feeding unit 40 to the exit of the fixing unit 60 by way of the image forming section 30, a reversing conveyance path 50B for returning a sheet having one side printed to the image forming section 30 in the case of printing both sides of the sheet, a switchback conveyance path 50C for conveying a sheet from a downstream end of the main conveyance path 50A to an upstream end of the reversing conveyance path 50B, and a horizontal conveyance path 50D (sheet conveyance path) for conveying a sheet in a horizontal direction from the downstream end of the main conveyance path 50A to the sheet discharge opening 10E provided in a left surface 10L of the apparatus main body 10. Most of the horizontal conveyance path 50D is formed by the sheet conveyance path provided in the conveying unit 55.
A registration roller pair 51 is arranged upstream of the secondary nip portion in the main conveyance path 50A. A sheet is temporarily stopped at the registration roller pair 51 in a stopped state for a skew correction. Thereafter, the registration roller pair 51 is driven and rotated by a driver (not shown) at a predetermined timing for image transfer, whereby the sheet is fed to the secondary nip portion.
A discharge roller 53 is arranged at a most downstream end of the conveyance path 50. The discharge roller 53 feeds a sheet to a post-processing apparatus arranged on the left surface 10L of the apparatus main body 10 through the sheet discharge opening 10E. Note that, in an image forming apparatus to which no post-processing apparatus is attached, a sheet discharge tray 10TR (
The conveying unit 55 is a unit for conveying a sheet carried out from the fixing unit 60 to the sheet discharge opening 10E. In the image forming apparatus 1 of this embodiment, the fixing unit 60 is arranged on the side of the right surface 10R of the apparatus main body 10 and the sheet discharge opening 10E is arranged on the side of the left surface 10L of the apparatus main body 10 facing the right surface 10R. Thus, the conveying unit 55 conveys a sheet in the horizontal direction from the right surface 10R to the left surface 10L of the apparatus main body 10. The conveying unit 55 is mountable into the apparatus main body 10 and constitutes a part of the apparatus main body.
The image forming apparatus 1 further includes the unillustrated post-processing apparatus. As described above, the post-processing apparatus is arranged on the left surface 10L of the apparatus main body 10. The post-processing apparatus receives sheets from the sheet discharge opening 10E and applies a predetermined post-processing to the sheets, and then stacks the sheets. Post-processings applied to the sheets include stapling and bookbinding.
The fixing unit 60 is a fixing device of an induction heating type for applying a fixing process for fixing a toner image to a sheet, and includes a heating roller 61, a fixing roller 62, a pressure roller 63, a fixing belt 64 and an induction heating unit 65. The pressure roller 63 is pressed into contact with the fixing roller 62 to form a fixing nip portion. A sheet passes through the fixing nip portion, whereby a toner image transferred to the sheet is fixed to the sheet.
Further, the image forming apparatus 1 includes a curl correcting device 7.
In the fixing unit 60, the sheet is heated by the fixing roller 62 in applying the fixing process to the sheet. Further, the sheet is pressed against the fixing roller 62 by the pressure roller 63. At this time, the toner image is fixed to a surface of the sheet facing the fixing roller 62. Due to the contraction of the toner image by heat, the sheet may be so curled (curved) that a side facing the fixing roller 62 (first surface) is on an inner peripheral side and a side facing the pressure roller 63 (second surface) is on an outer peripheral side. If the sheet is curled, the storage property of the sheet discharged onto the sheet discharge tray 10TR or the post-processing apparatus is deteriorated. By correcting the curl by the curl correcting device 7, the storage property of the sheet is stably maintained.
Next, the curl correcting device 7 according to this embodiment is described in detail with reference to
The correcting unit 70 is a main part of the curl correcting device 7. The correcting unit 70 is mounted on an unillustrated frame which is a part of the apparatus main body 10 on front and rear sides of the conveying unit 55. Note that the frame corresponds to parts of the lower housing 73 and the upper housing 74 to be described later. The sheet is conveyed to the left in the horizontal conveyance path 50D to pass through the interior of the correcting unit 70.
The correcting unit 70 includes a plurality of inner conveyance path inside configured to be a part of the sheet conveyance path. The plurality of inner conveyance path includes a first conveyance path SP1 and a third conveyance path SP3 both which have the after-mentioned nip portion N and a second conveyance path SP2 which does not has the nip portion N.
The correcting unit 70 has a substantially cylindrical shape extending in a front-back direction. The correcting unit 70 includes an outer peripheral portion 70A. Further, the correcting unit 70 includes unit shafts 700 (third rotary shaft). The unit shafts 700 serve as a rotary shaft in the rotation of the correcting unit 70. The unit shafts 700 are a pair of shaft portions extending in the front-back direction on opposite side surfaces of the correcting unit 70. A center of rotation CT (see
The elastic rollers 701 are rotated about the elastic roller shaft 701A (
The hard roller 702 is rotated about a hard roller shaft 702A (
In other words, the correcting unit 70 supports the elastic rollers 701 and the hard roller 702 rotatably about axes by rotatably supporting the elastic roller shaft 701A and the hard roller shaft 702A. Further, the correcting unit 70 includes the unit shafts 700 arranged parallel to the elastic roller shaft 701A and is supported in the lower housing 73 and the upper housing 74 rotatably about the unit shafts 700.
The rear flange portion 703 is a side wall portion arranged perpendicularly to the unit shaft 700 on a rear side end part of the correcting unit 70. The rear flange portion 703 is composed of two wall portions spaced apart in the front-back direction. Specifically, the rear flange portion 703 includes a first rear flange 703A and a second rear flange 703B. The first rear flange 703A is the wall portion arranged on an axially outer side of the rear flange portion 703. The second rear flange 703B is the wall portion arranged on an axially inner side of the rear flange portion 703. Note that, as shown in
The front flange portion 704 is a side wall portion arranged perpendicularly to the unit shaft 700 on a front side end part of the correcting unit 70. The front flange portion 704 is composed of two wall portions spaced apart in the front-back direction. Specifically, the front flange portion 704 includes a first front flange 704A and a second front flange 704B. The first front flange 704A is the wall portion arranged on an axially outer side of the front flange portion 704. The second front flange 704B is the wall portion arranged on an axially inner side of the front flange portion 704. The first and second front flanges 704A, 704B are connected by a plurality of coupling bars (not shown) arranged at intervals in the circumferential direction.
The first guide portion 711 is a pair of plate-like members extending between the second rear flange 703B and the second front flange 704B (
The second guide portion 712 is arranged at a side opposite to the first guide portion 711 across the center of rotation CT of the correcting unit 70. The second guide portion 712 is a pair of plate-like members extending between the second rear flange 703B and the second front flange 704B. Specifically, the second guide portion 712 includes a 21st guide 712A and a 22nd guide 712B. As shown in
The third guide portion 713 is a pair of plate-like members extending between the second rear flange 703B and the second front flange 704B. As shown in
The fourth guide portion 714 is a pair of plate-like members extending between the second rear flange 703B and the second front flange 704B. As shown in
The 11th and 12th conveyance paths 7A, 7B communicate with each other in the radial direction of the correcting unit 70 across the center of rotation CT of the correcting unit 70. Further, the 21st and 22nd conveyance paths 7C, 7D also communicate with each other in the radial direction of the correcting unit 70 across the center of rotation CT of the correcting unit 70.
Further, the correcting unit 70 includes an input gear 707, an intermediate gear 708 and a transmission gear 709 (
The input gear 707 is a gear arranged on the unit shaft 700 axially outward of the first rear flange 703A. The input gear 707 is rotatable relative to the unit shaft 700. The input gear 707 is coupled to a drive motor 722 to be described later via an unillustrated gear.
The intermediate gear 708 is a gear portion arranged to correspond to the aforementioned cut-off part of the first rear flange 703A. The intermediate gear 708 is rotatably supported on the second rear flange 703B. The intermediate gear 708 includes a first intermediate gear portion 708A and a second intermediate gear portion 708B. The first and second intermediate gear portions 708A, 708B are gear parts adjacently arranged in the axial direction. The first intermediate gear portion 708A is engaged with the input gear 707. The second intermediate gear portion 708B is engaged with the transmission gear 709 to be described alter. The intermediate gear 708 receives a rotational drive force from the input gear 707 and transmits the rotational drive force to the transmission gear 709.
The transmission gear 709 is a gear rotatably supported between the first and second rear flanges 703A, 703B. The transmission gear 709 rotates the hard roller shaft 702A via an unillustrated gear member. When a rotational drive force is transmitted from the intermediate gear 708 to the transmission gear 709, the hard roller 702 is rotated via the gear member. With the rotation of the hard roller 702, the elastic rollers 701 are rotated, following the rotation of the hard roller 702.
The curl correcting device 7 further includes the rotary motor 721 (drive unit) and the drive motor 722.
The rotary motor 721 (
The drive motor 722 is arranged behind the correcting unit 70. The drive motor 722 is a motor for generating a rotational drive force for rotating the hard roller 702 in the correcting unit 70 about the hard roller shaft 702A. The drive motor 722 is engaged with the input gear 707 of the correcting unit 70, whereby the rotational drive force of the drive motor 722 is transmitted to the input gear 707. The rotational drive force is transmitted from the input gear 707 to the hard roller shaft 702A via the intermediate gear 708, the transmission gear 709 and the gear member. As a result, the hard roller 702 is rotated by the rotational drive force of the drive motor 722. Note that the input gear 707 is arranged on the same axis as the unit shafts 700 of the correcting unit 70. Thus, even if the correcting unit 70 rotates, an engaged position of the input gear 707 and the drive motor 722 does not change and the rotational drive force is stably input to the input gear 707.
With reference to
The lower housing 73 is arranged below the correcting unit 70. The lower housing 73 includes a lower carry-in portion 731, a lower supporting portion 732 and a lower carry-out portion 733.
The lower carry-in portion 731 is arranged below the horizontal conveyance path 50D and upstream of the correcting unit 70 in the sheet conveying direction and guides the sheet P toward the correcting unit 70. The lower supporting portion 732 is arranged downstream of the lower carry-in portion 731 in the sheet conveying direction and below the correcting unit 70. The lower supporting portion 732 defines a lower part of a space in which the correcting unit 70 rotates. The lower carry-out portion 733 is arranged downstream of the lower supporting portion 732 and the correcting unit 70 in the sheet conveying direction. The lower carry-out portion 733 guides the sheet P carried out from the nip portion N of the correcting unit 70 toward the downstream roller pair 55R.
The upper housing 74 is arranged above the correcting unit 70. The upper housing 74 includes an upper carry-in portion 741, an upper supporting portion 742 and an upper carry-out portion 743.
The upper carry-in portion 741 is arranged above the horizontal conveyance path 50D and upstream of the correcting unit 70 in the sheet conveying direction and guides the sheet P toward the correcting unit 70. The upper supporting portion 742 is arranged downstream of the upper carry-in portion 741 in the sheet conveying direction and above the correcting unit 70. The upper supporting portion 742 defines an upper part of the space in which the correcting unit 70 rotates. The upper carry-out portion 743 is arranged downstream of the upper supporting portion 742 and the correcting unit 70 in the sheet conveying direction. The upper carry-out portion 743 guides the sheet P carried out from the nip portion N of the correcting unit 70 toward the downstream roller pair 55R.
Next, a curl correcting operation of the curl correcting device 7 according to this embodiment is described. The control unit 800 is for totally controlling the curl correcting device 7 and electrically connected to a detection sensor 76 and a curl amount detection sensor 77 (detector) in addition to the aforementioned rotary motor 721 and the drive motor 722 as transmission and reception destinations of control signals.
The detection sensor 76 (
With reference to
The control unit 800 is composed of a CPU (Central Processing unit), a ROM (Read Only Memory) storing a control program, a RAM (Random Access Memory) used as a work area of the CPU and the like, and operates to functionally include the drive controller 810 (drive controller), the counter 820 and a storage 830 by executing the control program.
The drive controller 810 controls the rotation of the correcting unit 70 and that of the hard roller 702 by controlling the rotary motor 721 and the drive motor 722. Specifically, the drive controller 810 moves the correcting unit 70 between a first position, a second position and a third position to be described later according to sheet information of a sheet being conveyed in the horizontal conveyance path 50D. Note that the sheet information of the sheet may be information detected by the curl amount detection sensor 77 or may be sheet information (specification including paper type, paper thickness, etc.) input from an unillustrated input unit of the image forming apparatus 1.
The counter 820 counts a pulse step signal for the rotation of the rotary motor 721 based on a detection timing of the detection piece by the detection sensor 76. Based on the count result of the counter 820, the drive controller 810 controls the rotation of the rotary motor 721. As a result, a rotational angle (rotational position) of the correcting unit 70 is controlled.
The storage 830 stores a table for the calculation of a curl amount of a sheet P according to the characteristic value (distance) detected by the curl amount detection sensor 77 in advance. The drive controller 810 derives the curl amount and curl direction of the sheet with reference to the table stored in the storage 830 based on the detection result of the curl amount detection sensor 77. The rotation of the correcting unit 70 and the rotational angle of the correcting unit 70 are determined based on the curl amount and curl direction.
Next, the curl correction of the sheet P is described with reference to
Specifically, the drive controller 810 judges that the sheet P (P1 in
When the correcting unit 70 is arranged at the first position, the aforementioned 11th and 12th conveyance paths 7A, 7B form a first conveyance path SP1. Specifically, the first conveyance path SP1 extends in the correcting unit 70 and communicates with the horizontal conveyance path 50D and forms a part of the horizontal conveyance path 50D by arranging the correcting unit 70 at the first position about the unit shafts 700. In this case, the sheet P1 is conveyed through the nip portion N.
The sheet P1 is conveyed into the correcting unit 70 through a clearance between the lower carry-in portion 731 of the lower housing 73 and the upper carry-in portion 741 of the upper housing 74 (direction of an arrow DP of
The sheet P1 having passed through the nip portion N is carried out from the correcting unit 70 while passing through a clearance between the 21st and 22nd guides 712A, 712B. Then, the sheet P1 is conveyed toward the downstream roller pair 55R while further passing through a clearance between the lower and upper carry-out portions 733, 743.
On the other hand, depending on the paper quality of the sheet P being conveyed in the horizontal conveyance path 50D, the sheet P carried out from the fixing unit 60 may be not curled. The drive controller 810 judges that the sheet P (P2 in
When the correcting unit 70 is arranged at the second position, the aforementioned 21st and 22nd conveyance paths 7C, 7D form a second conveyance path SP2. Specifically, the second conveyance path SP2 extends in the correcting unit 70 and communicates with the horizontal conveyance path 50D and forms a part of the horizontal conveyance path 50D by arranging the correcting unit 70 at the second position about the unit shafts 700. In this case, the sheet P2 is conveyed while passing through an area different from the nip portion N without passing through the nip portion N.
The sheet P2 is conveyed into the correcting unit 70 through the clearance between the lower carry-in portion 731 of the lower housing 73 and the upper carry-in portion 741 of the upper housing 74 (direction of an arrow DP of
Further, depending on the paper quality of the sheet P, the sheet P carried out from the fixing unit 60 may be curled upwardly. In this case, the sheet is so curled that the first surface is on the outer peripheral side and the second surface is on the inner peripheral side. In other words, as shown in
When the correcting unit 70 is arranged at the third position, the aforementioned 11th and 12th conveyance paths 7A, 7B form a third conveyance path SP3. Specifically, the third conveyance path SP3 extends in the correcting unit 70 and communicates with the horizontal conveyance path 50D and forms a part of the horizontal conveyance path 50D by arranging the correcting unit 70 at the third position about the unit shafts 700. In this case, the nip portion N is formed in a state where the arrangement of the elastic rollers 701 and the hard roller 702 is switched from that in the first conveyance path SP1. Then, the sheet P3 enters the nip portion N from a side (outer peripheral side of the correcting unit 70) opposite to the sheet P1 conveyed in the first conveyance path SP1.
The sheet P3 is conveyed into the correcting unit 70 through the clearance between the lower carry-in portion 731 of the lower housing 73 and the upper carry-in portion 741 of the upper housing 74 (direction of an arrow DP of
The sheet P3 having passed through the nip portion N is carried out from the correcting unit 70 while passing through a clearance between the 11th and 12th guides 711A, 711B. Then, the sheet P3 is conveyed toward the downstream roller pair 55R while further passing through the clearance between the lower and upper carry-out portions 733, 743.
As described above, if the sheet P being conveyed in the horizontal conveyance path 55D is curled, it can be carried into the nip portion N by arranging the correcting unit 70 at the first or third position. In this case, the curl is properly corrected in the curved nip portion N formed between the elastic rollers 701 and the hard roller 702. On the other hand, if the sheet P being conveyed in the horizontal conveyance path 55D is not curled, it is conveyed without passing through the nip portion N by arranging the correcting unit 70 at the second position. Thus, regardless of whether or not the sheet P being conveyed in the horizontal conveyance path 50D is curled, the sheet P can be carried out in a curl-free state. In other words, the sheet P, which is not curled, is inhibited from being carried into the nip portion N, thereby preventing the sheet P from being erroneously curled. As a result, regardless of whether or not the sheet P being conveyed in the horizontal conveyance path 50D is curled, the sheet P can be carried out in the curl-free state.
Particularly, the position of the correcting unit 70 is set according to the sheet information of the sheet P being conveyed in the horizontal conveyance path 50D, specifically, the curled state of the sheet P detected by the curl amount detection sensor 77. Thus, the arrangement of the correcting unit 70 can be accurately switched according to an actual state of the sheet P being conveyed in the horizontal conveyance path 50D. Further, even if the sheet P is curled in a different direction, the curl can be corrected by arranging the correcting unit 70 at the first or third position.
Further, in a cross-section intersecting with the unit shafts 700, the first and second conveyance paths SP1, SP2 intersect with each other with the center of rotation CT as an intersection. Thus, the first and second conveyance paths SP1, SP2 extend to pass through the center of rotation CT. As a result, the switch of the conveyance path is realized by the rotation of the correcting unit 70 when the sheet P is conveyed along the first or second conveyance path SP1 or SP2. At this time, since the positions of the entrances and exits of the first and second conveyance paths SP1, SP2 of the correcting unit 70 overlap, it is possible to commonly use the conveyance paths upstream of and downstream of the correcting unit 70. In other words, it is not necessary to widen the conveyance paths upstream of and downstream of the correcting unit 70 or to provide a plurality of conveyance paths at each of the upstream and downstream sides of the correcting unit 70. Further, since the first and second conveyance paths SP1, SP2 are perpendicularly arranged in the cross-section intersecting with the unit shafts 700, the first and second conveyance paths SP1, SP2 can be switched by rotating the correcting unit 70 by 90° about the unit shafts 700.
Further, in the above embodiment, the curl correcting device 7 can be arranged utilizing the conveying unit 55. Further, the curl of the sheet P is stably corrected before the sheet P reaches the post-processing apparatus.
Although the curl correcting device 7 and the image forming apparatus 1 with the same according to the embodiment of the present disclosure have been described above, the present disclosure is not limited to this. For example, the following modifications can be adopted.
(1) In the above embodiment, the nip portion N is arranged at one end side (12th conveyance path 7B) of the first conveyance path SP1 with respect to the center of rotation CT and the other end side (11th conveyance path 7A) of the first conveyance path SP1 with respect to the center of rotation CT is composed only of the conveyance path in the cross-section intersecting with the unit shafts 700. The present disclosure is not limited to this.
The correcting unit 90 is characterized by including inner conveyor rollers 903, 904 (conveyor roller) in an 11th conveyance path 9A corresponding to the 11th conveyance path 7A of the previous embodiment inside. Specifically, a nip portion N is formed by elastic rollers 901 and a hard roller 902 arranged at one end side (one of the upstream side and the downstream side) of a first conveyance path SP4 of the correcting unit 90 with respect to a center of rotation CT. Further, the inner conveyor rollers 903, 904 are arranged at the other end side (the other of the upstream side and the downstream side) of the first conveyance path SP4 of the correcting unit 90 opposite to the nip portion N with respect to the center of rotation CT and convey a sheet P. In this case, the sheet P can be stably conveyed toward the nip portion N in the correcting unit 90. Further, the sheet P carried out from the nip portion N can be stably conveyed toward the outside of the correcting unit 90.
(2) Although the curl amount detection sensor 77, which is a distance measuring sensor, is used as the sensor for detecting the characteristic value corresponding to the curl amount of the sheet P in the above embodiment, the present disclosure is not limited to this. Another sensor may be used as the sensor for detecting the characteristic value corresponding to the curl amount. For example, a light reflection type sensor may be used to detect the curl amount of the sheet P from an angle of reflection of light irradiated toward the leading end part of the sheet P.
(3) Although the correcting units 70 and 90 can be arranged at the first, second and third positions in the above embodiment and modification, the present disclosure is not limited to this. In another modification, a correcting unit may be switched between the first and second positions. Further, a rotating direction associated with a position change of the correcting unit may be appropriately selected from a clockwise direction and a counterclockwise direction in consideration of a switching time.
Although the present disclosure has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present disclosure hereinafter defined, they should be construed as being included therein.
Number | Date | Country | Kind |
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2013-070182 | Mar 2013 | JP | national |
Number | Name | Date | Kind |
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8588674 | Nanayama | Nov 2013 | B2 |
8862047 | Furushige et al. | Oct 2014 | B2 |
Number | Date | Country |
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2009-29554 | Feb 2009 | JP |
Number | Date | Country | |
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20140294478 A1 | Oct 2014 | US |