JP2012171703A - Decurl system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct (decurl) warpage (curl) generated in a sheet or an envelope.SOLUTION: A decurl system 10 includes: a first sheet conveying roller pair 11 disposed at the upstream side of a sheet conveying path for conveying the sheet (or the envelope) P; a second sheet conveying roller pair 18 disposed at the downstream side of the sheet conveying path; a curl correcting member 16 disposed fixed between the first sheet conveying roller pair 11 and the second sheet conveying roller pair 18 that has a convex surface 16c for bending the curl generated in the sheet (or the envelope) P in the reverse direction; and a back tension imparting means that imparts back tension for pressing the sheet (or the envelope) P along the convex surface 16c of the curl correcting member 16 so as to bend the curl generated in the sheet (or the envelope) P in the reverse direction when a leading end Pf of the sheet (or the envelope) P in the conveying direction reaches the second sheet conveying roller pair 18 through the first sheet conveying roller pair 11.

Description

  The present invention can be applied to paper such as plain paper, thick paper, thin paper, matte paper, and a printing apparatus capable of printing an image on an envelope, and can be used to correct (decal) warpage (curl) generated on the paper or the envelope. About.

  In general, printing devices that print images on plain paper, thick paper, thin paper, matte paper, and envelopes, inkjet printing devices, stencil printing devices, laser beam printers, thermal transfer printing devices, etc. are for home use or business use. It is often used as.

  In this type of printing apparatus, there is a decurling roller apparatus that can correct (decal) a curved wrinkle (curl) generated on a recording paper when an image is printed on the recording paper as a printing medium (see, for example, Patent Document 1).

  In the decurling roller device disclosed in Patent Document 1, although not shown here, a hard roller that is rotationally driven by a driving source when correcting curled wrinkles generated on the recording paper, and a larger roller than this hard roller. An elastic roller that has a diameter and is driven by a hard roller, and the elastic roller is pressed against the hard roller through the recording paper against the restoring force by rotating the cam member. It is stated that wrinkles can be corrected.

JP 2010-155668 A

  By the way, in the decurling roller device disclosed in Patent Document 1, the curled wrinkles generated on the recording paper can be corrected by sandwiching and transporting the recording paper between the hard roller on the driving side and the elastic roller on the driven side. The decurling roller device requires a hard roller driving mechanism for rotating the hard roller, a cam member for applying a pressing force to the elastic roller, and a cam member driving mechanism for rotating the cam member. However, there is a problem that the decurling roller device itself is increased in size.

  Further, in the decurling roller device, the elastic roller is weak in material with respect to the hard roller, so that it is easily worn and deformed.

  Accordingly, an object of the present invention is to provide a highly reliable decurling device that can reduce the number of parts and can be downsized when correcting a warp generated in a sheet or an envelope.

The present invention has been made in view of the above problems, and the invention according to claim 1 is a decurling device for correcting a warp generated in a sheet or an envelope,
In order to convey the sheet or the envelope along the sheet conveyance path, a first sheet conveyance unit installed on the upstream side of the sheet conveyance path, and the sheet spaced apart from the first sheet conveyance unit A second sheet conveying means installed on the downstream side of the conveying path;
A warp correction member fixedly installed between the first paper transport unit and the second paper transport unit, and having a curved surface for warping in the opposite direction to the warp generated in the paper or the envelope;
When the paper or the envelope is transported by the first paper transport means and the leading end of the paper or the envelope in the transport direction reaches the second paper transport means, the paper or the envelope is generated on the paper or the envelope. Back tension applying means for applying a back tension for pressing the paper or the envelope along the curved surface of the warp correction member so as to be warped in a direction opposite to the warp;
A decal device characterized by comprising:

The invention according to claim 2 is the decal device according to claim 1,
The back tension applying unit connects the first sheet conveying unit to a first drive source to set the sheet conveying speed to the first speed, and the second sheet conveying unit is configured to perform the second driving. The paper conveyance speed is set to a second speed higher than the first speed by connecting to a source, and the leading end of the paper or the envelope in the conveyance direction reaches the second paper conveyance means. A decurling apparatus characterized in that a back tension generated according to a speed difference between the first speed and the second speed is sometimes applied to the paper or the envelope.

The invention according to claim 3 is the decal device according to claim 2,
When an electromagnetic clutch is connected between the first paper conveying means and the first driving source, and the first paper conveying means is driven by the first driving source by connecting the electromagnetic clutch. In addition, after the leading end of the sheet or the envelope in the conveyance direction reaches the second sheet conveying unit and the back tension is applied to the sheet or the envelope, the electromagnetic clutch is disconnected from the first drive source. This is a decal device.

  According to the decurling device of claim 1, the sheet or the envelope is placed between the first sheet conveying unit installed on the upstream side of the sheet conveying path and the second sheet conveying unit installed on the downstream side of the sheet conveying path. Since the warp correction member having a curved surface for warping in the opposite direction to the generated warp is fixedly installed, the paper or envelope is transported by the first paper transport means, and the leading end of the paper or envelope in the transport direction is the first. When the paper transport means 2 is reached, the back tension is applied to the curved surface of the warp correction member so that the back tension is applied to the paper or the envelope so that the paper or the envelope is warped in the opposite direction. The decurling device can be provided at a low cost by reducing the number of parts because the warp generated in the paper or envelope can be corrected by pressing along and the drive mechanism is not required for the warping correction member itself. In addition, the decurling device can be downsized, and the warp correction member has rigidity, so that the warp generated on the paper or envelope can be corrected reliably without causing wrinkles or deformations. be able to.

Further, according to the decal device according to claim 2, in the decal device according to claim 1,
The back tension applying means sets the first paper conveying means to the first speed via the first driving source, and sets the second paper conveying means to the first speed via the second driving source. In accordance with the speed difference between the first speed and the second speed when the leading end in the transport direction of the paper or envelope reaches the second paper transport means. Since the generated back tension is applied to the paper or the envelope, the warp generated on the paper or the envelope can be corrected with high reliability while suppressing the occurrence of wrinkles.

  Further, according to the decurling device according to claim 3, in the decurling device according to claim 2, an electromagnetic clutch is connected between the first paper transporting means and the first drive source so that the first paper transporting means is used. When driven, the electromagnetic clutch is disconnected from the first drive source after the front end of the sheet or envelope in the conveying direction reaches the second sheet conveying means and the back tension is applied to the sheet or envelope. It is possible to suppress the sheet slip phenomenon that occurs on the first sheet conveying unit side due to the speed difference between the first sheet conveying unit and the second sheet conveying unit.

2A and 2B are perspective views for explaining a sheet applied to the decurling apparatus according to the present invention, in which FIG. 1A shows a state before the warp is corrected, and FIG. (C) is the figure which showed the state after correcting curvature by the decal apparatus based on this invention. It is the block diagram typically shown in order to demonstrate the decurling apparatus of Example 1 which concerns on this invention. (A), (b), (c) is a timing chart showing the operations of the sheet conveyance speed, the sheet leading edge detection sensor, and the pressing mechanism, respectively, when the decurling apparatus according to the first embodiment of the present invention is operated. . It is the block diagram typically shown in order to demonstrate the decurling apparatus of Example 2 which concerns on this invention. (A), (b), (c) is a timing chart showing the operation of the sheet conveyance speed, the sheet leading edge detection sensor, and the electromagnetic clutch when the decurling apparatus according to the second embodiment of the present invention is operated. .

  Hereinafter, an embodiment of a decurling apparatus according to the present invention will be described in detail in the order of Embodiment 1 and Embodiment 2 with reference to FIGS.

  The decal device according to the present invention is configured to be applicable to paper such as plain paper, thick paper, thin paper, matte paper, and a printing device (not shown) that prints an image on an envelope. It has a function to correct (decal) warping (curl).

  At this time, if the paper or envelope is initially warped, the decurling device according to the present invention is installed in the paper conveyance path between the paper feeding unit and the printing unit (not shown). What is necessary is just to install the decurling device according to the present invention in the paper conveyance path between the printing unit and the paper discharge unit when warping occurs during printing.

  Further, the decal device according to the present invention is installed in the paper conveyance path of the paper independently provided outside the printing device without installing the decurling device according to the present invention in the printing device, and the paper or envelope is attached here. After correcting the initial warp that has occurred, a sheet with the corrected warp may be used in the printing apparatus.

  Here, before describing the decurling apparatus according to the present invention, the paper will be briefly described with reference to FIGS. Note that an envelope (not shown) may be used instead of the paper, and the warp generated in the envelope can be corrected in the same manner as the paper. Therefore, in the following description, the case where the paper is used will be described.

  As shown in FIG. 1A, when the paper P before being warped is set with the front surface Pb side up with respect to the back surface Pa side, the front end portion Pf side in the paper transport direction and the front end portion An upward curl (up curl) occurs on the rear end Pr side opposite to the Pf side.

  On the other hand, as shown in FIG. 1B, while the decurling device according to the present invention is applied to the paper P before the warp correction to correct the warp, the upward generated on the paper P before the warp correction is generated. It is warped in the opposite direction with respect to the warp (up curl), and is deformed so that a downward warp (down curl) is generated on the front end portion Pf side and the rear end portion Pr side in the paper transport direction.

  When correcting the warp of the paper P before warp correction by the decurling device according to the present invention, the down curl state shown in FIG. 1B is added to the up curl state shown in FIG. After the warp is offset and the warp is corrected, the leading end Pf side and the rear end Pr side of the paper P are flat without any warp as shown in FIG.

  A configuration of the decurling apparatus 10 according to the first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 2A, the decurling apparatus 10 according to the first embodiment of the present invention is arranged in the sheet conveyance path H in order to correct (decurl) the warp (curl) generated in the sheet (or envelope) P. is set up.

  In the decurling apparatus 10 according to the first embodiment described above, the first sheet conveyance roller pair 11 serving as the first sheet conveyance unit is installed on the upstream side of the sheet conveyance path H of the sheet P. The first paper transport roller pair 11 is a pair of a first drive roller 11A and a first driven roller 11B, both of which are formed using a rubber material, and the first driven roller 11B is a first one by a spring (not shown) or the like. It can be pressed toward one drive roller 11A.

  At this time, the first drive roller 11A is connected to the motor 12 serving as a drive source and the gear train 13, and is set so that the sheet conveyance speed becomes a constant speed V. 12 is operated, and the rotation of the motor 12 is decelerated by the gear train 13, whereby the first driving roller 11A is rotated in the clockwise direction, and the first driven roller 11B driven by the first driving roller 11A is a sheet. It can be rotated counterclockwise via P.

  Further, a back tension applying member (hereinafter referred to as a friction member) 14 formed using a friction material such as felt or rubber cork operates in accordance with a command from the control unit 30 downstream of the first sheet conveying roller pair 11. It is provided so as to be able to come into contact with and separate from the paper P conveyed along the paper conveyance path H through the pressing mechanism 15.

  At this time, the pressing mechanism 15 uses a solenoid (not shown) or a piezoelectric element to advance and retract the friction member 14 in the direction of the arrow, and the friction member 14 is retracted from the paper transport path H at the initial time indicated by the two-dot chain line arrow. On the other hand, during the operation indicated by the solid line arrow, the friction member 14 enters the sheet conveyance path H, and along an inclined surface 16b of a later-described warp correction member 16 provided to face the friction member 14. A back tension can be applied to the sheet P by contacting the surface Pb of the moving sheet P. Thereby, the friction member (back tension applying member) 14 and the pressing mechanism 15 constitute the back tension applying means of the first embodiment.

  Further, downstream of the friction member 14, the warp correction member 16 and the paper guide member 17 are fixedly installed facing each other across the paper transport path H.

  The warp correction member 16 described above is integrally formed in a substantially mountain shape using a rigid resin material or a lightweight metal material, the bottom surface 16a is formed in a flat surface, and the paper P is conveyed in the transport direction. An inclined surface 16b is formed on the left side that is the upstream side, and a convex curved surface 16c that is connected to the inclined surface 16b and warps in the opposite direction to the warp generated in the paper P projects upward. Further, the right side surface 16d is cut out toward the bottom surface 16a.

  The back surface Pa side of the paper P is movable along the inclined surface 16b and the convex curved surface 16c formed on the left side of the warp correction member 16.

  On the other hand, the paper guide member 17 is also integrally formed using a rigid resin material or a light metal material, the upper surface 17a is formed as a flat surface, and the left and right side surfaces 17b and 17d face downward. The concave curved surface 17c is formed between the left and right side surfaces 17b and 17d so as to face the convex curved surface 16c of the warp correction member 16 with a predetermined interval.

  At this time, the concave curved surface 17c of the paper guide member 17 prevents the leading end portion Pf of the paper P moving along the convex curved surface 16c of the warp correction member 16 from derailing from the paper conveyance path H upward. It has a function of guiding the leading end Pf of the paper P so as to reach a second paper conveyance roller pair 18 described below.

  In addition, a second sheet conveying roller pair 18 serving as a second sheet conveying unit is disposed on the downstream side of the sheet conveying path H with a distance from the first sheet conveying roller pair 11 serving as a first sheet conveying unit. Thus, the friction member 14, the warp correction member 16, and the paper guide member 17 are installed between the first paper transport roller pair 11 and the second paper transport roller pair 18.

  Similarly to the first paper conveyance roller pair 11, the second paper conveyance roller pair 18 also has a pair of a second drive roller 18A and a second driven roller 18B both formed using a rubber material, The second driven roller 18B can be pressed toward the second drive roller 18A by a spring or the like (not shown), and the second paper transport roller pair 18 is provided on the right side surface 16d of the warp correction member 16 and the paper guide member 17. It is installed close to the right side surface 17d.

  At this time, similarly to the first drive roller 11A, the second drive roller 18A is also connected to the motor 12 and the gear train 13 so that the sheet conveyance speed is set to a constant speed V. The motor 12 is operated according to the command of 30 and the rotation of the motor 12 is decelerated by the gear train 13 to rotate the second driving roller 18A in the clockwise direction and to follow the second driving roller 18A. The driven roller 18B can rotate counterclockwise via the paper P.

  In the first embodiment, the first and second paper transporting units use the first and second paper transporting roller pairs 11 and 18, but the present invention is not limited to this. A structure is also possible in which P is mounted on a rotatable endless belt (not shown) while sucking air and the paper P is conveyed integrally with the endless belt.

  Further, a paper front end detection sensor 19 is installed on the downstream side of the second paper transport roller pair 18 by using a transmission type optical sensor (or a reflection type optical sensor). The leading end Pf in the transport direction of the paper P transported by the second paper transport roller pair 18 is detected.

  Here, operation | movement of the decurling apparatus 10 of Example 1 comprised as mentioned above is demonstrated using FIG.2 and FIG.3 (a)-(c) together.

  When the decurling apparatus 10 according to the first exemplary embodiment is operated, the motor 12 and the gear train 13 are operated via the control unit 30 to rotationally drive the first and second paper conveying roller pairs 11 and 18.

  Then, the back surface Pa of the paper P is set in the state where the upward curling (up curl) has occurred on the leading edge Pf side and the trailing edge Pr side of the paper P described above with reference to FIG. When the sheet P is brought into contact with the first drive roller 11A of the sheet conveyance roller pair 11 and the surface Pb of the sheet P is brought into contact with the first driven roller 11B, the sheet P is drawn by the first sheet conveyance roller pair 11. As shown in FIG. 3 (a), it is nipped and conveyed at a constant speed V.

  Thereafter, the sheet P reaches the second sheet conveying roller pair 18 along the convex curved surface 16c from the inclined surface 16b formed on the left side of the warp correction member 16, and the sheet P is moved to the second sheet conveying roller. When the sheet is further nipped and conveyed by the pair 18 at a constant speed V, the leading edge Pf of the sheet P is detected by the sheet leading edge detection sensor 19 as shown in FIG. Since the pressing mechanism 15 is turned on as shown in FIG. 3C, the friction member (back tension applying member) 14 enters the paper conveyance path H and moves along the inclined surface 16b of the warp correction member 16. The back tension is applied to the paper P by contacting the surface Pb of the paper P to be printed.

  In the first embodiment, the pressing mechanism 15 is turned on after the paper P passes through the second paper conveyance roller pair 18 and the paper leading edge detection sensor 19 detects the leading edge Pf of the paper P. If the elapsed time from the start of conveyance of the paper P to the front end portion Pf of the paper P passing through the second paper conveyance roller pair 18 is known in advance without using the front edge detection sensor 19, the elapsed time is used for pressing. It is also possible to turn on the mechanism 15.

  Therefore, when the paper P reaches the second paper transport roller pair 18, the friction member 14 is pressed against the paper P via the pressing mechanism 15 to apply a back tension to the paper P.

  Since the paper P to which the back tension is applied by the friction member 14 is pressed along the convex curved surface 16c of the warp correction member 16, the paper P warps in a direction opposite to that before the warp correction. As described above, downward curling (down curl) occurs on the front end portion Pf side and the rear end portion Pr side of the paper P, and thereafter, the rear end portion Pr of the paper P becomes the second paper transport roller pair. After passing through 18, the warp before correction is canceled out, and the leading edge Pf side and the trailing edge Pr side of the paper P are flat and flat as described with reference to FIG. At the same time, the warp correction is completed after suppressing the generation of wrinkles.

  As described above, according to the decurling apparatus 10 of the first embodiment, when correcting the warp generated in the sheet (or envelope) P, the first sheet conveying roller pair 11 and the sheet installed on the upstream side of the sheet conveying path H. A warp correction member 16 having a convex curved surface 16c for warping in the opposite direction to the warp generated in the paper (or envelope) P between the second paper transport roller pair 18 installed on the downstream side of the transport path H. The paper (or envelope) P is transported by the first paper transport roller pair 11, and the leading end portion Pf of the paper (or envelope) P in the transport direction reaches the second paper transport roller pair 18. Warp the paper (or envelope) P so that the back tension is applied to the paper (or envelope) P by the back tension applying means 14 and 15 and warped in the opposite direction to the warp generated on the paper (or envelope) P. Convex surface of straightening member 16 By pressing along 6c, the warp generated in the paper (or envelope) P can be corrected, and the warp correction member 16 itself does not require a drive mechanism, so the number of parts can be reduced. The decurling device 10 can be provided at a low cost, and the decurling device 10 according to the first embodiment can be reduced in size. Further, since the warp correction member 16 has rigidity, the sheet (or envelope) P is not worn or deformed. The generated warp can be corrected with high reliability while suppressing the occurrence of wrinkles.

  The configuration of the decurling apparatus 20 according to the second embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 4, the decurling apparatus 20 according to the second embodiment of the present invention also conveys paper to correct (decurl) the warp (curl) generated in the paper (or envelope) P as in the first embodiment. It is installed in the road H.

  In the decurling device 20 according to the second embodiment described above, the first sheet conveying roller pair 21 serving as the first sheet conveying unit on the upstream side of the sheet conveying path H of the sheet P includes the left side surface 24b of the warp correction member 24 described later and The paper guide member 25 is installed close to the left side surface 25b. The first pair of paper transport rollers 21 is a pair of a first drive roller 21A and a first driven roller 21B, both of which are formed using a rubber material, and the first driven roller 21B is configured by a spring (not shown) or the like. It can be pressed toward one drive roller 21A.

  At this time, the first drive roller 21A is connected to the first geared motor 22 and the electromagnetic clutch 23, which are the first drive source, and is set so that the sheet conveyance speed becomes the first speed V1, The first geared motor 22 and the electromagnetic clutch 23 are operated by a command from the control unit 40 to rotate the first driving roller 21A in the clockwise direction, and the first driven roller 21B driven by the first driving roller 21A loads the paper P. Via the counterclockwise direction.

  When the first geared motor 22 and the electromagnetic clutch 23 are deactivated by a command from the control unit 40, the first sheet conveying roller pair 21 is accompanied by the conveyance of the sheet P by the second sheet conveying roller pair 26 described later. Only can be rotated.

  Further, a warp correction member 24 and a paper guide member 25 are fixedly installed opposite to each other across the paper transport path H downstream of the first paper transport roller pair 21.

  The warp correction member 24 described above is integrally formed using a rigid resin material or a lightweight metal material, the bottom surface 24a is formed as a flat surface, and the left and right side surfaces 24b and 24d are respectively obliquely downward and inward. A bottom surface 24a is cut out, and a convex curved surface 24c is formed between the left and right side surfaces 24b and 24d so as to warp in the opposite direction to the warp generated in the paper P.

  And the back surface Pa side of the paper P is movable along the convex curved surface 24c in the warp correction member 24.

  On the other hand, the paper guide member 25 is also integrally formed using a rigid resin material or a light metal material, the upper surface 25a is formed as a flat surface, and the left and right side surfaces 25b and 25d face downward. The concave curved surface 25c is formed between the left and right side surfaces 25b and 25d so as to face the convex curved surface 24c of the warp correction member 24 with a predetermined interval.

  At this time, the concave curved surface 25c of the paper guide member 25 prevents the leading end portion Pf of the paper P moving along the convex curved surface 24c of the warp correction member 24 from derailing from the paper conveyance path H upward. A function of guiding the leading end portion Pf of the paper P so as to reach the second paper conveyance roller pair 26 is provided.

  In addition, a second sheet conveying roller pair 26 serving as a second sheet conveying unit is disposed on the downstream side of the sheet conveying path H with a distance from the first sheet conveying roller pair 21 serving as a first sheet conveying unit. Thus, the warp correction member 24 and the paper guide member 25 described above are installed between the first paper transport roller pair 21 and the second paper transport roller pair 26.

  Similarly to the first paper conveyance roller pair 21, the second paper conveyance roller pair 26 described above is a pair of a second driving roller 26 </ b> A and a second driven roller 26 </ b> B both formed using a rubber material, The second driven roller 26B can be pressed toward the second drive roller 26A by a spring or the like (not shown), and the second paper transport roller pair 26 is provided on the right side surface 24d of the warp correction member 24 and the paper guide member 25. It is installed close to the right side surface 25d.

  At this time, the second drive roller 26A is directly connected to the second geared motor 27 serving as a second drive source so that the sheet conveyance speed becomes the second speed V2 higher than the first speed V1. The second geared motor 27 is operated by the command of the control unit 40 to rotate the second drive roller 26A in the clockwise direction, and the second driven roller 26B driven by the second drive roller 26A is moved to the sheet P. It is possible to rotate counterclockwise through the.

  In the second embodiment, the first and second paper transporting units use the first and second paper transporting roller pairs 21 and 26. However, the present invention is not limited to this. For example, A structure in which the paper P is mounted on a rotatable endless belt (not shown) while sucking air and the paper P is transported integrally with the endless belt is also possible.

  Further, a paper front end detection sensor 28 is installed on the downstream side of the second paper transport roller pair 26 using a transmission type optical sensor (or a reflection type optical sensor). The leading end portion Pf in the transport direction of the paper P transported by the second paper transport roller pair 26 is detected.

  Here, operation | movement of the decurling apparatus 20 of Example 2 comprised as mentioned above is demonstrated using FIG.4 and FIG.5 (a)-(c) together.

  When the decurling device 20 according to the second embodiment is operated, the first geared motor 22 and the electromagnetic clutch 23 are operated (ON) via the control unit 40 to rotate and drive the first sheet conveying roller pair 21. Then, the second geared motor 27 is operated (ON) to rotate the second paper transport roller pair 26.

  Then, the back surface Pa of the paper P is set in the state where the upward curling (up curl) has occurred on the leading edge Pf side and the trailing edge Pr side of the paper P described above with reference to FIG. When the first paper transport roller pair 21 is brought into contact with the first drive roller 21A and the surface Pb of the paper P is brought into contact with the first driven roller 21B, the first paper transport roller pair 21 and the first geared motor Since the electromagnetic clutch 23 is connected (ON) to the sheet 22, the sheet conveyance speed of the sheet P is set to the first speed V 1 as shown in FIG. 5A by the first sheet conveyance roller pair 21. It is nipped and conveyed.

  Thereafter, the paper P reaches the second paper transport roller pair 26 while being along the convex curved surface 24c in the warp correction member 24, and the paper P is transported at the first paper transport speed by the second paper transport roller pair 26. Since the sheet is further nipped and conveyed at the second speed V2 higher than the speed V1, back tension generated according to the speed difference between the first speed V1 and the second speed V2 is added to the paper P.

  Accordingly, the first and second geared motors 22 and 27 that rotationally drive the first and second paper transport roller pairs 21 and 26 are driven in accordance with the speed difference between the first speed V1 and the second speed V2. This is the back tension applying means of Example 2 for applying tension to the paper P.

  At this time, if the speed difference generated between the first paper transport roller pair 21 and the second paper transport roller pair 26 is kept as it is, the slip phenomenon of the paper P occurs on the first paper transport roller pair 21 side. Therefore, in order to suppress the slip phenomenon, after the leading end portion Pf of the sheet P passes through the second sheet conveying roller pair 26, the sheet P is detected by the sheet leading end detection sensor 28 as shown in FIG. The control unit 30 receives the result and turns off the electromagnetic clutch 23 as shown in FIG. 5 (c) to turn the electromagnetic clutch 23 into the first sheet conveying roller pair 21 and the first geared. Since the first paper transport roller pair 21 is disconnected from the motor 22, the driving by the first geared motor 22 and the electromagnetic clutch 23 is released, and according to the transport of the paper P by the second paper transport roller pair 26. Only 1 of the paper conveying roller pair 21 is rotated.

  In the second embodiment, the electromagnetic clutch 23 is turned off after the paper P passes through the second paper conveyance roller pair 26 and the paper leading edge detection sensor 28 detects the leading edge Pf of the paper P. If the elapsed time from the start of conveyance of the paper P to the leading edge Pf of the paper P passing through the second paper conveyance roller pair 26 is known in advance without using the leading edge detection sensor 28, the elapsed time is used for electromagnetic It is also possible to turn off the clutch 23.

  Accordingly, when the paper P reaches the second paper conveyance roller pair 26, the back tension generated according to the speed difference between the first speed V1 and the second speed V2 is applied to the paper P, and then the electromagnetic wave is applied. The clutch 23 is disconnected from the first geared motor 22.

  Then, the paper P to which the back tension generated according to the speed difference between the first speed V1 and the second speed V2 is applied is pressed along the convex curved surface 24c of the warp correction member 24, and before the warp correction. 1 is warped in the opposite direction, and as described above with reference to FIG. 1B, downward curling (down curl) occurs on the front end portion Pf side and the rear end portion Pr side of the paper P. Thereafter, After the trailing edge Pr of the sheet P passes through the second sheet conveying roller pair 26, the warp before correction is canceled out, and as described above with reference to FIG. The Pf side and the rear end Pr side are flat without warping, and the warpage correction is completed after suppressing the generation of wrinkles.

  As described above, according to the decurling apparatus 20 of the second embodiment, when correcting the warp generated in the paper (or envelope) P, the first paper transport roller pair 21 and the paper installed on the upstream side of the paper transport path H. A warp correction member 24 having a convex curved surface 24c for warping in the opposite direction to the warp generated in the paper (or envelope) P between the second paper transport roller pair 26 installed on the downstream side of the transport path H. The paper (or envelope) P is transported by the first paper transport roller pair 21, and the leading end portion Pf of the paper (or envelope) P in the transport direction reaches the second paper transport roller pair 26. Warp the paper (or envelope) P so that the back tension is applied to the paper (or envelope) P by the back tension applying means 22 and 27 and warped in the opposite direction to the warp generated on the paper (or envelope) P. Convex curved surface of the straightening member 24 By pressing along 4c, the warp generated in the paper (or envelope) P can be corrected, and the warp correction member 24 itself does not require a drive mechanism, so the number of parts can be reduced, so that the second embodiment The decurling device 20 can be provided at a low cost, and the decurling device 20 of the second embodiment can be reduced in size. Further, since the warp correction member 24 has rigidity, it can be applied to the paper (or envelope) P without wear or deformation. The generated warp can be corrected with high reliability while suppressing the occurrence of wrinkles.

10: Decal device of Example 1,
11... First sheet conveying means (first sheet conveying roller pair),
11A ... 1st drive roller, 11B ... 1st driven roller,
12 ... Driving source (motor), 13 ... Gear train,
14 ... Back tension applying member (friction member), 15 ... Pressing mechanism,
16 ... Warp correction member, 16b ... Inclined surface, 16c ... Convex curved surface,
17 ... paper guide member, 17c ... concave curved surface,
18 ... second sheet conveying means (second sheet conveying roller pair),
18A ... second driving roller, 18B ... second driven roller,
19: Paper leading edge detection sensor,
20 ... Decal device of Example 2,
21... First paper transport means (first paper transport roller pair),
21A ... 1st drive roller, 21B ... 1st driven roller,
22 ... 1st drive source (1st geared motor), 23 ... Electromagnetic clutch,
24 ... Warp correction member, 24c ... Convex curved surface,
25 ... paper guide member, 25c ... concave curved surface,
26. Second sheet conveying means (second sheet conveying roller pair),
26A ... second driving roller, 26B ... second driven roller,
27: second drive source (second geared motor), 28: paper leading edge detection sensor,
30 ... control unit of the first embodiment, 40 ... control unit of the second embodiment,
P ... paper, Pa ... back surface, Pb ... front surface, Pf ... front end, Pr ... rear end,
V: Paper transport speed by the first and second paper transport roller pairs 11, 18;
V1 ... Paper conveyance speed by the first paper conveyance roller pair 21;
V2: Paper conveyance speed by the second paper conveyance roller pair 26.

Claims (3)

A decurling device that corrects a warp generated on paper or an envelope,
In order to convey the sheet or the envelope along the sheet conveyance path, a first sheet conveyance unit installed on the upstream side of the sheet conveyance path, and the sheet spaced apart from the first sheet conveyance unit A second sheet conveying means installed on the downstream side of the conveying path;
A warp correction member fixedly installed between the first paper transport unit and the second paper transport unit, and having a curved surface for warping in the opposite direction to the warp generated in the paper or the envelope;
When the paper or the envelope is transported by the first paper transport means and the leading end of the paper or the envelope in the transport direction reaches the second paper transport means, the paper or the envelope is generated on the paper or the envelope. Back tension applying means for applying a back tension for pressing the paper or the envelope along the curved surface of the warp correction member so as to be warped in a direction opposite to the warp;
A decal device characterized by comprising:   The back tension applying unit connects the first sheet conveying unit to a first drive source to set the sheet conveying speed to the first speed, and the second sheet conveying unit is configured to perform the second driving. The paper conveyance speed is set to a second speed higher than the first speed by connecting to a source, and the leading end of the paper or the envelope in the conveyance direction reaches the second paper conveyance means. 2. The decurling apparatus according to claim 1, wherein a back tension generated according to a speed difference between the first speed and the second speed is sometimes applied to the paper or the envelope.   When an electromagnetic clutch is connected between the first paper conveying means and the first driving source, and the first paper conveying means is driven by the first driving source by connecting the electromagnetic clutch. In addition, after the leading end of the sheet or the envelope in the conveyance direction reaches the second sheet conveying unit and the back tension is applied to the sheet or the envelope, the electromagnetic clutch is disconnected from the first drive source. The decurling apparatus according to claim 2.

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