JP2016130155A - Sheet processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet processing device which corrects an elongation difference between a center part and end parts, i.e. the center part and the end parts when viewed in a width direction perpendicular to a sheet transfer direction, in the sheet transfer direction.SOLUTION: A sheet processing device includes: humidification means 202 for providing a moisture content to each sheet P; tensile force application means 101 provided at the downstream side of the humidification means in a sheet transfer direction and used to apply a tensile force acting in the sheet transfer direction to a center area when viewed in a width direction perpendicular to the sheet transfer direction; feeding/loading means 203 for loading each sheet fed toward the humidification means; and discharge loading means 207 for loading each sheet to which the moisture content is provided from the humidification means after the sheet is discharged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet processing apparatus for processing a sheet.

  2. Description of the Related Art Conventionally, an image forming apparatus using an electrophotographic system develops a latent image formed on a photosensitive drum as an image carrier with a developing device to form a visible image, and this visible image (toner image) is electrostatically applied to a sheet. Transfer using force. Next, the toner image transferred to the sheet is fixed on the sheet by applying heat and pressure with a fixing device, and an image is formed on the sheet.

  In such a fixing device of an image forming apparatus, an elastic pressure roller is pressed against a fixing roller having a heat source such as a heater and maintained at a predetermined temperature to form a nip portion. A heat roller fixing method for fixing a toner image on a sheet is employed.

  However, in the heat fixing process of these fixing devices, heat and pressure are applied to the sheet on which the toner image is transferred, so that the sheet passes through the nip portion of the fixing device or the sheet passes through the nip portion of the fixing device. After passing, moisture evaporates from the inside of the sheet. Due to the change in the amount of moisture inside the sheet and the stress applied to the sheet, a phenomenon called curl where the sheet bends and a phenomenon called wave where the sheet becomes wavy rather than straight are generated. .

  Here, a sheet-like paper that is most commonly used as a sheet is viewed at the fiber level. Paper is composed of short fibers entangled with each other, and moisture is contained inside or between the fibers. Furthermore, since the fiber and water are in an equilibrium state with hydrogen bonds formed, smoothness is maintained.

  However, when heat and pressure are applied to the paper in the fixing process, the fibers are displaced due to the pressure. When heat is applied and moisture evaporates in this state, further hydrogen bonds are formed between the fibers and deform. If this paper is left unattended, it absorbs moisture from the environment, and the hydrogen bonds between the fibers are cut off again to return to the original state. However, there is no moisture between some fibers of the paper, thereby maintaining the deformation of the paper. The deformation pattern includes the above-described curl and corrugation, and the curl is generated due to the expansion / contraction difference between the front and back of the paper, and the corrugation is generated due to the expansion / contraction difference between the center and the edge of the paper.

  Patent Document 1 discloses the following configuration in order to prevent curling and undulation due to loss of moisture from a sheet in a fixing process of an image forming apparatus using an electrophotographic method.

  That is, in a paper humidifier that humidifies a paper that has been heat-fixed and sent from an image forming apparatus, the moisture content of the paper after the humidification process exceeds the moisture content of the paper in the paper feed tray. The structure which has a humidification part which humidifies so that it may not exist is disclosed.

  The paper humidifier is used so as to be connectable to an electrophotographic image forming apparatus. In the image forming apparatus, sheets are fed one by one from the sheet feeding tray, toner images are formed on the sheets, and the formed toner images are heated and fixed on the sheets. Furthermore, the sheet humidifying device can be connected to a bookbinding processing device that performs bookbinding processing downstream of the sheet humidifying device in the sheet transport direction.

  When paper is used as a sheet, the paper that has been dehydrated by heat and pressure during the fixing process is replenished with water again by the paper humidifier, improving the wave and curl. To do. When the water content of the paper increases, the Young's modulus of the paper itself decreases and the stiffness decreases, and the waviness is reduced. Further, when moisture enters the gap between the fibers, the bonds between the fibers once hydrogen-bonded by the fixing device are disconnected again, and the wave is reduced.

JP 2009-234679 A

  However, as in Patent Document 1, the moisture content after the humidification processing of the paper does not exceed the moisture content of the paper in the paper feed tray. It is difficult to align the lengths of the center and both ends of the sheet in the transport direction later.

  In other words, simply applying moisture to the paper does not lead to a water content necessary for breaking hydrogen bonds between the fibers and accelerating expansion and contraction in the paper transport direction due to a tension load on the paper center.

  In particular, in the case of a fixing device having a wide nip as in the belt fixing method, in order to prevent the sheet from wrinkling in the process of passing the sheet through the nip portion, the end portion from the center portion in the width direction perpendicular to the sheet conveying direction in the nip portion. The conveyance speed on the part side is set high. In such a case, after the sheet passes through the nip portion of the fixing device, the end portion of the sheet extends in the transport direction more than the vicinity of the central portion, and a wave is generated at the end portion of the sheet. In such a situation, the curl at the leading and trailing edges of the paper can be corrected, but it is difficult to correct the difference in elongation in the transport direction between the edge and the center of the paper. Therefore, the paper wave problem remains.

  In addition, in the corrugation correcting apparatus in which the paper that has been corrugated in the process of passing through the fixing device in the image forming apparatus is connected to the image forming apparatus, the image is already in the environment for, for example, one day or more after the image formation is completed. It is not possible to correct the wave out of the left output paper.

  Similarly, in the wave straightening device connected to the image forming apparatus, it is not possible to correct the wave generated on the paper due to non-uniform entrance / exit of moisture in the state of being left in the environment, not in the image forming process.

  An object of the present invention is to correct the difference in elongation between the central portion and the end portion in the width direction perpendicular to the sheet conveyance direction, thereby improving the waviness of the sheet.

  In order to achieve the above object, the present invention provides a humidifying means for imparting moisture to a sheet and a central area in the width direction orthogonal to the sheet conveying direction, provided downstream of the humidifying means in the sheet conveying direction. A tension applying unit for applying a tension in a direction, a feeding and stacking unit for stacking a sheet to be fed toward the humidifying unit, and a sheet applied with a tension by the tension applying unit after stacking Discharge stacking means.

  According to the present invention, it is possible to improve the waviness of the sheet by correcting the difference in elongation between the central portion and the end portion in the width direction perpendicular to the sheet conveying direction.

FIG. 3 is a cross-sectional view illustrating the paper wave straightening device according to the first embodiment. FIG. 3 is a top external view illustrating the paper wave straightening device according to the first exemplary embodiment. FIG. 3 is a right side external view illustrating the paper wave straightening device according to the first exemplary embodiment. The humidification apparatus of Example 1, and the perspective view which shows a water storage tank periphery. FIG. 3 is a block diagram illustrating a control relationship of the sheet wave correction device according to the first exemplary embodiment. 6 is a flowchart showing control of the sheet wave correction device according to the first exemplary embodiment. (A) and (b) are sectional views showing a paper pulling and conveying apparatus of Example 1. FIG. 3 is a perspective view illustrating a paper pulling and conveying device according to the first exemplary embodiment. FIG. 3 is a top view illustrating the paper pulling and conveying apparatus according to the first exemplary embodiment. The external view which shows the shape of a sheet | seat. The table which shows the state of the sheet | seat by experiment. (A) is a top view which shows the spray humidification apparatus of Example 1, (b) is a perspective view. FIG. 5 is a cross-sectional view illustrating a paper wave straightening device according to a second embodiment. FIG. 6 is an external perspective view showing a humidifying liquid cartridge of Example 2. FIG. 6 is a block diagram illustrating a control relationship of a correction apparatus for paper waves according to a second embodiment.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

[Example 1]
The configuration of the sheet wave straightening device 201 as a sheet processing apparatus according to this embodiment will be described with reference to FIGS.

  Here, the sheet is a sheet to be recorded, and is in a state where an image is formed or in a state before an image is formed. Specific examples of the sheet include plain paper (paper, recording paper), a resin sheet that is a substitute for plain paper, cardboard, and overhead projector.

  First, with reference to FIG. 5, the control relationship of the entire sheet wave correcting device 201 will be described. FIG. 5 is a block diagram showing the control relationship of the entire sheet wave correction device 201. The control unit 201C of the paper wave correction device 201 is a computer system having a CPU, a memory, an arithmetic unit, an I / O port, a communication interface, a drive circuit, and the like. The control by the control unit 201C is performed by the CPU executing a predetermined program stored in the memory. The control unit 201C of the sheet wave straightening device 201 controls operations of the spray humidifying device 202 serving as a humidifying unit constituting the device, the sheet tension conveying device 101 serving as a tension applying unit, and the water supply pump 206. In the drawing, the description of blocks that are not directly related to the description of the present invention is omitted.

  Next, with reference to FIGS. 1 to 3, FIG. 1 illustrates a schematic configuration of a paper wave straightening device 201 according to the present embodiment. FIG. 1 is a cross-sectional view showing the entire sheet wave correcting device 201 according to this embodiment, FIG. 2 is a top external view, and FIG. 3 is a side external view.

  The sheet P used for the correction device 201 of the paper wave may be output from an image forming apparatus such as a copying machine or a printer, or may be a sheet before image formation before being used for a copying machine or a printer. .

  That is, it may be a sheet that is output from an image forming apparatus such as a copying machine or a printer and in which a wave has already occurred. Sheets before image formation that have been wavy due to non-uniform entry and exit of moisture when left in various environments, such as high temperature and high humidity or low temperature and low humidity conditions, wrapped in wrapping paper and removed from the wrapping paper Etc. Of these waves, any sheet intended for correction can be used.

  The sheet wave straightening device 201 shown in FIGS. 1, 2, and 3 has a spray humidifying device 202 as a humidifying means for applying moisture to a sheet. Further, a sheet tension conveying device 101 is provided downstream of the spray humidifying device 202 in the sheet conveying direction, and serves as a tension applying unit for applying tension in the conveying direction to a central region in the width direction orthogonal to the sheet conveying direction. doing. In addition, a feeding tray 203 as a feeding and stacking unit for stacking sheets to be fed toward the spray humidifier 202 is provided. Further, a discharge tray 207 is provided as a discharge stacking unit for stacking the sheets given tension by the sheet pulling and conveying apparatus 101 after discharging.

  In the sheet wave straightening device 201 shown in FIGS. 1, 2, and 3, the sheets P stacked on the feeding tray 203 are separated one by one by a feeding roller 208 and a separation pad 213 that are feeding units. In this way, the image is sent in the direction of arrow A in FIG. Further, the sheet P is guided by the conveyance guide 214 in the conveyance direction downward (in the direction of arrow B in FIG. 1), and is conveyed after the front end of the sheet P passes through the nip of the conveyance roller pair 211 and is humidified by the spray humidifier 202. It is sent to the roller pair 212.

  The sheet P that has passed through the nip of the conveyance roller pair 212 is continuously sent to the paper pulling conveyance device 101. When the sheet P humidified to a predetermined moisture amount by the spray humidifier 202 passes through the paper pulling and conveying device 101, the central portion in the width direction orthogonal to the sheet conveying direction is pulled in the conveying direction. Thereby, the difference in the length in the sheet conveying direction between the end portion and the central portion in the sheet width direction can be reduced, and the wave undulation can be improved. Thereafter, the sheet P with improved ripples is turned in the conveyance direction in the left direction of FIG. 1 (direction of arrow C in FIG. 1) by the conveyance guide 209, and is then moved out of the sheet wave correction device 201 by the discharge roller pair 210. The paper is discharged and stacked on the discharge tray 207.

  The configuration around the spray humidifier 202 as a humidifier will be described with reference to FIGS. 4, 12 (a), and 12 (b). FIG. 4 is a perspective view showing the structure around the conveyance roller pair 211, the conveyance roller pair 212, the spray humidifier 202, the water storage tank 204, and the water supply pump 206. FIG. 12A is a top view of the spray humidifier 202, and FIG. 12B is a perspective view.

  As shown in FIG. 4, the water storage tank 204 is a water storage tank in which a humidifying liquid L for humidifying the sheet P is accommodated. The humidifying liquid L stored in the water storage tank 204 is supplied with water in the direction of arrow D shown in FIGS. 1 and 4 through the water supply pipe H toward the spray humidifier 202 by the water supply pump 206 as needed. The humidifying liquid L has water as a main component, and may be one in which a surfactant is blended in consideration of humidification efficiency and permeability to the sheet P.

  As shown in FIGS. 12A and 12B, the spray humidifier 202 is a humidifying means for spraying (applying) the humidifying liquid L, which is a liquid, in the form of a mist. As shown in FIG. 12B, a plurality of jets 252 for spraying the humidifying liquid L in the form of a mist are opened on the surface of the spray humidifier 202 facing the sheet P. The plurality of jet nozzles 252 are arranged in the sheet width direction. The spray humidifier 202 sprays the humidifying liquid L in a fan shape in the direction of the arrow indicated by 250 in FIG. 12A on the sheet P in response to a command from the control unit 201C (see FIG. 5). Each fan-shaped spray width on the surface of the sheet P is W shown in FIG. 12 (a), but the spray width (spray area) from the adjacent jet nozzle 252 to the sheet slightly overlaps the jet nozzle 252. The width, interval, and spray angle are set. Therefore, the surface of the sheet P is sprayed and humidified without a gap in the width direction.

  A shutter 251 shown in FIG. 12B is an opening / closing member for opening / closing each ejection port 252 of the spray humidifier 202. The shutter 251 opens and closes each outlet 252 by reciprocating in the direction of arrow E in FIG. 12B according to a command from the control unit 201C (see FIG. 5A), and switches between spraying and non-spraying of the humidifying liquid L. Spray only where needed.

  Any of the spray humidifiers 202 can be used. For example, a rotor dampening device manufactured by WEKO can be suitably used. However, the spray humidifying device 202 in the present embodiment is not limited to the above-described rotor dampening device. Various sprayable devices can be employed. For example, a device that injects only necessary portions by arranging a large number of shower nozzles in the width direction may be used.

  Next, the sheet pulling and conveying apparatus 101 will be described with reference to FIGS. The sheet pulling / conveying device 101 applies a tension for extending the central portion in the width direction in the conveying direction to the sheet P guided between the inlet guide 102 and the inlet guide 121 after passing through the spray humidifying device 202 described above. A plurality of rotating body pairs.

  Here, as a plurality of rotating body pairs, a first roller pair (first rotating body pair) described below and a second roller pair provided on the downstream side in the sheet conveying direction from the first roller pair. (Second rotating body pair) is illustrated.

  The first roller pair is a first driving roller that is a rotatable first roller, and a first pressure roller that is pressed against the first driving roller to form a nip portion to sandwich and convey the sheet. It consists of a certain first pressure roller.

  The second roller pair is provided downstream of the first roller pair in the sheet conveying direction. The second roller pair is a second driving roller that is a rotatable second roller, and a second pressure roller that is pressed against the second driving roller to form a nip portion to sandwich and convey the sheet. It consists of a certain second pressure roller.

  The sheet pulling and conveying apparatus 101 includes a first driving roller 104 and a first pressure roller 105 that constitute a first rotating body pair shown in FIG. 7, a second driving roller 106 and a second driving roller 106 that constitute a second rotating body pair. The sheet P is nipped and conveyed by the two pressure rollers 107. Then, the sheet pulling and conveying apparatus 101 applies tension to the sheet P to extend the central portion in the width direction of the sheet P in the conveying direction while conveying the sheet P. Then, the sheet P is guided between the exit guide 117 and the exit guide 118 and is discharged out of the sheet pulling and conveying apparatus 101.

  The first driving roller 104, the first pressure roller 105, the second driving roller 106, and the second pressure roller 107 include elastic rubbers 104b, 105b, 106b, and 107b such as silicon, NBR, and EPDM. The elastic rubbers 104b, 105b, 106b, and 107b are formed on the surface layers of the roller shafts 104a, 105a, 106a, and 107a using high-rigidity materials such as stainless steel and steel, respectively. In this embodiment, the elastic rubbers 104b, 105b, 106b, 107b all have an outer diameter φ of 20 mm. Further, as shown in FIG. 8, the elastic rubbers 105b and 107b of the first pressure roller 105 and the second pressure roller 107 are centered in the sheet width direction so as to be equal to the sheet passing center (width direction center). It is formed in the region of the part length L1. Here, the sheet passing center is a position in the center in the width direction which is a reference when the sheet is conveyed. The length L1 is shorter than the length in the width direction of the sheet P in which the wave shown in FIG. In this embodiment, L1 = 100 mm.

  Thus, the elastic rubbers 105b and 107b are arranged at the center in the width direction. Thereby, the first drive roller 104 and the first pressure roller 105 form a nip portion at the center in the width direction. Here, the elastic rubber portion is provided at the center in the width direction of the first pressure roller 105 and the second pressure roller 107, but the present invention is not limited to this. An elastic rubber portion may be provided at the center in the width direction of the first drive roller 104 and the second drive roller 106.

  Further, a conveyance guide 114 and a conveyance guide 115 which are guide members for guiding a sheet are provided between the nip portions of the first roller pair and the second roller pair, and the distance between the nip portions is 25 mm.

  The first drive roller 104 and the second drive roller 106 are supported at both ends of the roller shafts 104a and 106a by a drive side plate 119 via bearings (not shown).

  In the first pressure roller 105, both end portions of the roller shaft 105a are supported by the first pressure plate 113 via bearings (not shown). The first pressure plate 113 is rotatably supported by the pressure side plate 120 via a first rotation shaft (not shown), and the bottom surface is urged by the first pressure spring 109. As a result, the first pressure roller 105 is pressed against the first drive roller 104 to form a nip portion.

  In the second pressure roller 107, both end portions of the roller shaft 107a are supported on the second pressure plate 112 via bearings (not shown). The second pressure plate 112 is rotatably supported by the pressure side plate 120 via a second rotation shaft (not shown), and the bottom surface is urged by the second pressure spring 108. As a result, the second pressure roller 107 is pressed against the second driving roller 106 to form a nip portion.

  As shown in FIG. 7, the entrance guide 121 is provided with a reflected light type sheet sensor 103 for detecting the arrival of the sheet P.

  FIG. 9 is a top view illustrating the driving of the first drive roller 104 and the second drive roller 106.

  As shown in FIG. 9, the driving gears 104G1 and 106G are held and fixed at one end of the first driving roller 104 and the second driving roller 106, respectively. The first drive roller 104 and the second drive roller 106 are rotated when the drive gears 104G1 and 106G receive a rotational drive force from the motor gear MG of the drive motor M that is a drive source. Specifically, the first drive roller 104 is rotated by receiving a rotational drive force via the drive transmission gears 123, 124, 125, the clutch gear CLG, and the drive gear 104G1 described above. The second drive roller 106 is rotated by receiving rotational driving via the drive transmission gears 126, 127, 128, 129 and the drive gear 106G.

  The first pressure roller 105 and the second pressure roller 107 are pressed against the first drive roller 104 and the second drive roller 106, respectively. The first pressure roller 105 and the second pressure roller 107 rotate following the rotation of the first drive roller 104 and the second drive roller 106, respectively.

  The clutch gear CLG is fixed to the electromagnetic clutch CL. By energizing the electromagnetic clutch CL, the driving force between the clutch gear CLG and the drive transmission gear 124 is transmitted via the clutch shaft 132, and the first drive roller 104 rotates. On the other hand, if the electromagnetic clutch CL is not energized, the driving force between the clutch gear CLG and the driving transmission gear 12 is not transmitted, the driving force of the driving motor M is not transmitted to the driving gear 104G1, and the first driving roller 104 rotates. do not do.

  A drive gear 104G2 is fixed to the other end of the first drive roller 104, and is connected to a load means 131 such as a torque limiter or an electromagnetic brake via a drive transmission gear 130.

  Here, the function of the load means 131 will be described. Drive is transmitted to the first drive roller 104 and the second drive roller 106, the sheet P is sandwiched between the first drive roller 104 and the first pressure roller 105, and the second drive roller 106 and the second pressure roller 107 are Suppose that it is nipped and transported. While the drive from the drive motor M is transmitted to the first drive roller 104, the load by the load means is not transmitted to the first drive roller 104. When transmission of the driving force from the driving motor M to the first driving roller 104 is cut by the electromagnetic clutch CL, the sheet P is conveyed by the conveying force of the second driving roller 106 and the second pressure roller 107. . Since there is a one-way clutch between the first drive roller 104 and the drive motor M, when the sheet P is conveyed by the conveyance force of the second drive roller 106 and the second pressure roller 107, the first drive roller 104 Receives the force from the sheet P and rotates. At this time, the load unit 131 applies a load to the rotation of the first drive roller 104. When a load is applied to the rotation of the first drive roller 104, the sheet P sandwiched between the first drive roller 104 and the first pressure roller 105 and between the second drive roller 106 and the second pressure roller 107 is applied to the sheet P. Tensile stress is generated. That is, whether or not a tensile stress is generated on the sheet P can be controlled by whether or not the first driving roller 104 is driven.

  FIG. 6 is a flowchart regarding the drive control of the present embodiment, and FIG. 5 is a block diagram regarding the drive control of the present embodiment. FIG. 7 is a front sectional view of the paper pulling and conveying apparatus 101 for explaining the drive control of this embodiment. FIG. 7A is a front cross-sectional view at time 0 to Xmsec after the sheet sensor is turned on, and FIG. 7B is a front cross-sectional view at time Xmsec after the sheet sensor is turned on.

  The flowchart of FIG. 6 will be described. When the paper passing job signal 51 shown in FIG. 6 is input to the CPU (control means) (S5-1), the drive motor M is energized (S5-2). Simultaneously with the turning on of the drive motor M, the energization of the electromagnetic clutch CL is also turned on to start the paper feeding (S5-3). As a result, as described above, the drive of the drive motor M is transmitted to the drive gears 104G1 and 106G via the drive transmission gears, whereby the first drive roller 104 and the second drive roller 106 rotate.

  Thereafter, when the sheet P is guided to the entrance guide 121 in the sheet pulling and conveying apparatus 101 and the ON signal of the sheet sensor 103 is confirmed (S5-4), the energization of the electromagnetic clutch CL is turned off after Xmsec (S5-5). ). The value of X is the time from when the sheet sensor 103 is turned on until immediately after the leading edge of the sheet P is sandwiched in the nip portion of the second roller pair. It is determined by the distance to the nip portion of the roller pair. That is, the control unit determines that the sheet is nipped in the nip portion of the second roller pair from the predetermined distance from the sheet sensor 103 to the nip portion of the second roller pair and the conveyance speed of the sheet P. In this embodiment, since the conveyance speed of the sheet P is 300 mm / s and the distance from the sheet sensor 103 to the nip portion of the second roller pair is 45 mm, X = 160 msec is set.

  When the energization of the electromagnetic clutch CL is turned off X msec after the sheet sensor 103 is turned on, the drive to the first drive roller 104 is released. That is, as shown in FIG. 7A, since the electromagnetic clutch CL is in the ON state at 0 to Xmsec after the sheet sensor is turned on, the first driving roller 104 is conveyed to convey the sheet P. Thereafter, as shown in FIG. 7B, at the point of Xmsec after the sheet sensor is turned on, the leading edge of the sheet P is immediately after reaching the nip portion of the second roller pair, and the sheet P is moved by the second driving roller 106. It is conveyed by driving. At the same time, the electromagnetic clutch CL is turned off and no driving force is transmitted to the first driving roller 104, so that the first roller pair is driven to rotate.

  Since the first drive roller 104 is connected to the load means 131 via the drive gear 104G2 and the drive transmission gear 130, a torque load is generated to rotate the first drive roller 104. As a result, in FIG. 7B, the sheet P is conveyed while a tension force (tension in the conveyance direction) is generated between the first roller pair and the second roller pair. In this embodiment, the load torque of the load means 131 is set so that the tension force applied to the sheet P is about 6 kgf.

  In this embodiment, as shown in FIG. 8, the nip portion between the first roller pair and the second roller pair has a width of 100 mm at the center in the width direction of the sheet. As a result, the sheet P is configured to be applied with a tension force of about 6 kgf only from the front end to the rear end in the conveyance direction only at the center in the width direction. Thereafter, when the sheet passing is finished, the drive motor M is turned off (S5-6) and finished (S5-7). The above flow is repeated for the second and subsequent sheets.

  FIG. 10 illustrates the curl generated in the sheet P, the shape characteristics of the end wave, and the measurement method. The wave is measured with the sheet P placed on the measuring platen 700. Here, the length of the end portion of the sheet P in the sheet conveyance direction is L edge [mm], and the center length is L center [mm].

  Also, the curved shape Pwave generated at the upper or lower side of the sheet P shown in FIG. 10, that is, the end in the width direction perpendicular to the conveying direction is referred to as an end wave, and the gap between them on the measurement surface plate 700 is shown. The maximum value of Xmax was taken as the object of evaluation as the wave amount.

  FIG. 11 shows the results of an experiment for confirming the effect of the paper pulling and conveying apparatus 101 in the present embodiment conducted by the present inventors. In FIG. 11A, the edge length L edge [mm], the center length L center [mm], and the maximum wave amount X max of the sheet P output by the printer alone without using the paper wave straightening device 201 are shown. [Mm] is described. FIG. 11B shows the end length of each sheet P immediately after being printed out by the printer alone and after about several minutes have passed, and after performing the wave straightening process at 300 mm / s using the paper wave wave straightening device 201. L edge [mm], the center length L center [mm], and the maximum wave amount X max [mm] are described.

  As shown in FIG. 11B, when the paper is passed through the paper pulling / conveying device (passed at 300 mm / s), the sheet has a center length L center after being left for one day after passing through the paper pulling / conveying device. The amount of elongation is 0.6 mm. On the other hand, the extension amount of the end portion length L edge is 0.6 mm, and the difference between the end portion and the center length is 0 mm. That is, due to the effect of the paper pulling and conveying apparatus, the center portion of the sheet P was stretched, and as a result, the amount of elongation at the end portion and the center became substantially equal. As a result, the maximum wave amount was 3.3 mm as shown in FIG. 11A due to the equal sheet lengths at the end and the center. It improved to 0 mm, that is, about 1/3. In this example, the moisture content of the sheet exhibiting the above effect was 8% or more in a certain predetermined paper type.

  As described above, after humidifying more than a predetermined amount of water, the tension conveyance device is passed through and the central portion in the width direction of the sheet is pulled in the conveyance direction, so that the length of the sheet in the conveyance direction of the end portion and the central portion is You can reduce the difference and improve the wave.

  Also for sheets output from various image forming apparatuses regardless of the type of copying machine and printer, and sheets before image formation left in the use environment for use in these various image forming apparatuses In general, it is possible to correct the wave out.

[Example 2]
The paper wave straightening device 301 will be described with reference to FIGS. 13, 14, and 15. FIG. 13 is a cross-sectional view illustrating the entire sheet wave correcting device 301 according to the second embodiment. FIG. 14 is an external view showing a humidifying liquid cartridge in the sheet wave straightening device according to the second embodiment. FIG. 15 is a block diagram illustrating a control relationship of the sheet wave correcting device according to the second embodiment.

  Note that the paper wave straightening device 301 shown in the present embodiment is a paper paper straightening device smaller than the paper wave straightening device 201 of the first embodiment, and can be used on a desktop or the like.

  As illustrated in FIG. 15, the control unit 301 </ b> C of the paper wave correction device 301 according to the second embodiment includes a CPU, a memory, an arithmetic unit, an I / O port, a communication interface, a drive circuit, and the like as in the first embodiment. It is a computer system. The control by the control unit 301C is the same as that in the first embodiment in that the CPU executes a predetermined program stored in the memory.

  A paper wave straightening device 301 shown in FIG. 13 includes a humidifying means, a tension applying means, a feeding and stacking means, and a discharge and stacking means, similarly to the paper wave straightening device 201 according to the first embodiment. . In FIG. 13, the humidifying roller pair 308 is a humidifying unit that forms a nip portion by contacting each other and moisturizes the sheet by applying moisture to the sheet passing through the nip portion. The sheet pulling / conveying device 310 is a tension applying unit that is provided downstream of the humidifying roller pair 308 in the sheet conveying direction and applies tension in the conveying direction to a central region in the width direction orthogonal to the sheet conveying direction. The feeding tray 311 is a feeding and stacking unit for stacking sheets for feeding toward the humidifying roller pair 308. The discharge tray 312 is discharge stacking means for stacking the sheets, which are given tension by the sheet pulling and conveying device 310, after discharge.

  In the paper wave correction device 301 shown in FIG. 13, the sheets P stacked on the feed tray 311 are separated one by one by a pickup roller 302, a feed roller 303, and a separation roller 309, which are feeding units. 13 sent in the direction of arrow F. Further, the sheet P is guided downward in the conveyance direction by the conveyance guide 304 and sent to the conveyance roller pair 305. Thereafter, the sheet P is sent to the humidifying roller pair 308 by the conveying roller pair 305, humidified by the humidifying roller pair 308, and then sent to the paper pulling and conveying apparatus 310.

  The sheet P is humidified to a predetermined amount of moisture by the humidifying roller pair 308 and then passes through the paper pulling / conveying device 310 and pulls the central portion in the width direction perpendicular to the conveying direction in the conveying direction. Thereby, the sheet P can reduce the difference in length in the sheet conveying direction between the end portion in the width direction and the central portion, and can improve the wave undulation. Thereafter, the sheet P whose wave has been improved is discharged out of the paper wave correcting device 301 in the direction of arrow G shown in FIG. 13 and stacked on the discharge tray 312.

  The humidifying roller pair 308 includes a lower humidifying roller 308a immersed in the humidifying liquid L in the water supply cartridge 306 and an upper humidifying roller 308b facing the lower humidifying roller 308a. Each of the humidifying rollers of the lower humidifying roller 308a and the upper humidifying roller 308b constituting the humidifying roller pair 308 has a solid rubber layer mainly composed of NBR, silicon or the like on a shaft surface made of a metal rigid body such as stainless steel. It is the formed elastic roller.

  The humidifying liquid L in the water supply cartridge 306 is rotated in the clockwise direction in FIG. 13 by the lower humidifying roller 308a in which the lower portion is immersed in the humidifying liquid L. It is pumped up by the action of wettability of the rubber surface layer. The humidifying liquid L on the surface of the lower humidifying roller 308a is transferred to the surface of the upper humidifying roller 308b in contact with the lower humidifying roller 308a until the leading edge of the sheet P reaches the nip portion.

  The humidifying liquid L on the surfaces of the lower humidifying roller 308a and the upper humidifying roller 308b is sequentially transferred to the surface of the sheet P after the leading edge of the sheet P reaches the nip portion between the lower humidifying roller 308a and the upper humidifying roller 308b. Humidify.

  The humidifying liquid L is mainly composed of water as in the case of Example 1, and may be a mixture of a surfactant in consideration of the humidifying efficiency and permeability to the sheet P.

  As described above, the paper wave straightening device 301 shown in the present embodiment is more compact than the paper wave straightening device 201 of the first embodiment. This is done by exchanging them. As shown in FIG. 13, the paper wave straightening device 301 according to the present embodiment is provided with a back cover 317 that can be opened and closed in the direction of arrow K around the support hole 318 on the left end side of the bottom surface of the paper wave straightening device 301. ing. The water supply cartridge 306 can be attached to and detached from the apparatus main body in the direction of the arrow J in a state where the back cover 317 is opened in the direction of the arrow K around the support hole 318 to the position indicated by the two-dot chain line. .

  FIG. 14 shows the water supply cartridge 306 before being mounted on the paper wave correction device 301. On the upper surface of the water supply cartridge 306, as shown in FIGS. 13 and 14, an opening 306a (indicated by a broken line in FIG. 14) through which the lower humidification roller 308a is immersed is provided. The opening 306a of the water supply cartridge 306 is sealed with an adhesive seal S1 for sealing the humidifying liquid L. One end of the adhesive seal S1 is integrally formed with a knob portion S2 that is used when a person who replaces the water supply cartridge 306 removes the adhesive seal S1. After removing the adhesive seal S1 from the water supply cartridge 306, the person who replaces the water supply cartridge 306 attaches the water supply cartridge 306 above the paper wave correction device 301 in the direction of arrow J shown in FIG. Close.

  The paper pulling and conveying apparatus 310 has the same configuration as that of the paper pulling and conveying apparatus 101 described in the first embodiment. That is, the first drive roller 104 and the first pressure roller 105 constituting the first pair of rotating bodies in the first embodiment correspond to the first drive roller 315 and the first pressure roller 316 in the present embodiment, respectively. In the first embodiment, the second driving roller 106 and the second pressure roller 107 constituting the second rotating body pair correspond to the second driving roller 313 and the second pressure roller 314, respectively, in this embodiment. The other constituent elements of the paper pulling / conveying apparatus 101 are all provided for the paper pulling / conveying apparatus 310, and their operations are also the same, and thus the description thereof is omitted.

  By using the correction device 301 out of the sheet wave having the configuration and operation as described above, the same effects as those of the first embodiment can be obtained. In addition, the paper wave straightening device 301 shown in the present embodiment can provide a paper wave straightening device that is smaller than the paper wave straightening device 201 of the first embodiment.

[Other Embodiments]
In the embodiment described above, the sheet processing apparatus (sheet correction apparatus that corrects the corrugation and curling of the sheet) that performs processing on a sheet such as recording paper as a recording target is illustrated, but the present invention is not limited to this. Absent. For example, the same effect can be obtained even if the present invention is applied to a sheet processing apparatus that processes a sheet such as a document to be read.

  In the embodiment described above, the outer diameters of the first pressure roller 105 and the second pressure roller 107 are larger in the central region in the width direction perpendicular to the sheet conveyance direction than in the end region. Although the provided structure was illustrated, it is not limited to this. Other configurations may be used as long as tension in the conveyance direction is applied to the central region in the width direction of the sheet. Specifically, the outer diameter of at least one of the rotating bodies constituting the first rotating body pair and the second rotating body pair is set to be larger in the central region in the width direction perpendicular to the sheet conveying direction. Any structure that is larger than the end region may be used.

CL ... Electromagnetic clutch H ... Water supply pipe L ... Humidification liquid M ... Drive motor 101 ... Paper tension conveying device 103 ... Sheet sensor 104 ... First drive roller 104G1, 106G ... Drive gear 105 ... First pressure roller 106 ... Second drive Roller 107 ... second pressure roller 113 ... first pressure plate 117, 118 ... outlet guide 119 ... drive side plate 120 ... pressure side plate 201 ... paper wave correction device 201C ... control unit 202 ... spray humidification device 203 ... feeding tray 204 ... Water storage tank 206 ... Water supply pump 207 ... Discharge tray 251 ... Shutter 252 ... Jet outlet 306 ... Water supply cartridge 306a ... Opening 308 ... Humidification roller pair 308a ... Lower humidification roller 308b ... Upper humidification roller 310 ... Paper tension conveyance device 311 ... Feed tray 312 ... Discharge tray

Claims (6)

Humidifying means for applying moisture to the sheet;
Tension applying means provided downstream of the humidifying means in the sheet conveying direction, and for applying tension in the conveying direction to a central region in the width direction orthogonal to the conveying direction of the sheet;
A feeding and stacking unit for stacking sheets to be fed toward the humidifying unit;
Discharging and stacking means for stacking the sheets given tension by the tension applying means after discharging;
A sheet processing apparatus comprising:   The tension applying means includes a first rotating body pair that conveys a sheet, a second rotating body pair that is provided downstream of the first rotating body pair in the sheet conveying direction, and conveys the sheet, Load means for applying a load to the rotation of the first rotating body pair so that a tensile stress is generated in the sheet when the sheet is sandwiched between the first rotating body pair and the second rotating body pair; The sheet processing apparatus according to claim 1, further comprising:   At least one of the first rotating body pair and the second rotating body pair is a roller pair, and the outer diameter of the roller of the roller pair is such that the central portion in the width direction of the sheet is more than the end portion. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is large.   At least one of the nip portion formed by the first rotating body pair and the nip portion formed by the second rotating body pair is in the region of the central portion of the conveyed sheet in the width direction of the sheet. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is characterized.   The humidifying means is provided with a plurality of jets for spraying moisture on the sheet, and the size, interval, and spray angle of the jets are set so that spray areas from adjacent jets to the sheet overlap. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is characterized.   5. The sheet processing according to claim 1, wherein the humidifying unit includes a humidifying roller pair that contacts each other to form a nip portion and humidifies a sheet passing through the nip portion. apparatus.

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