JP4779945B2 - Sheet feeding apparatus and method - Google Patents

Description

  The present invention relates to a sheet feeding apparatus and method, and more particularly to a sheet feeding apparatus and method in a crimping apparatus that crimps a component to a substrate via a sheet with a crimping tool.

  For example, in the manufacturing process of flat display panels such as liquid crystal panels and plasma display panels, components such as TCP (Tape Carrier Package), FPC (Flexible Printed Circuit) and COG (Chip On Glass) are pressure-bonded to a panel as a substrate. There are processes for mounting or mounting a printed circuit board on a panel by pressing the printed circuit board on a TCP or FPC mounted on the panel, and a component crimping apparatus is used for the crimping process.

  When a component is crimped to a substrate with a component crimping device, an anisotropic conductive material as a bonding member is pasted on the substrate in advance, and the component is temporarily crimped to the substrate via this anisotropic conductive material, and the component crimping device To be supplied. In the component crimping apparatus, the component is pressed onto the substrate by pressurizing the component with a crimping tool while the substrate is supported by the backup stage. The anisotropic conductive material is made by dispersing conductive particles with Ni film formed on the surface of the resin particles in the thermosetting resin, and selects the part where conductivity should be obtained between the substrate and the part. By compressing the conductive plate, the conductive particles are brought into contact with each other and the substrate and the component are joined in a state in which the conductivity is secured at the site.

  By the way, in the main crimping step, the protruding anisotropic conductive material may adhere to the crimping surface of the crimping tool, and in this case, the subsequent final crimping step is adversely affected. Therefore, it is known to perform crimping between a crimping tool and a part via an adhesion preventing sheet. It is also known to perform pressure bonding via a cushioning sheet in order to absorb a minute variation in the flatness of the substrate and the thickness dimension of the electronic component and ensure a uniform pressure bonding state. Furthermore, in order to prevent these adhesion preventing sheets and cushioning sheets from being damaged by the heat of the crimping tool, it is also known to crimp these sheets and the crimping tool via a heat resistant sheet. It is also known to press-bond via a sheet obtained by combining any of these sheets.

  As shown in FIG. 8, as a sheet feeding apparatus in the method of crimping via the adhesion preventing sheet between the crimping tool and the component, as shown in FIG. 8, the sheet pulled out from the supply reel 32 that stores the sheet 31 in a wound state. 31 is configured to be wound around a take-up reel 33 that is rotated by a take-up motor 34 between a crimping tool 30 and a component (not shown), and the control unit 35 causes the take-up motor 34 to be driven. A drawing amount command unit 37 for instructing the motor driving unit 36 for a sheet drawing amount, and a drawing amount detection unit 39 for detecting the rotation amount of the take-up reel 33 by the encoder 38 and calculating the actual sheet drawing amount are provided. In response to a command from the command unit 37, the winding motor 34 is operated via the winding motor driving unit 36 so that the sheet 31 is pulled out by a necessary amount. The actual withdrawal amount and the command withdrawal amount are compared by the comparison / determination unit 40. If they are different from each other, it is determined that the sheet reel collection capacity of the supply reel 32 is lost and the supply reel 32 is locked. A device that detects sheet breakage is known (see, for example, Patent Document 1).

  In addition, a feeding mechanism is provided to take up the sheet fed from the supply roll with a take-up roll between the electronic component and the crimping tool, and is configured to feed the required amount of sheet for each crimping operation. Prior to the crimping operation by the tool, the take-up roll is reversely rotated by a predetermined amount, and the sheet is drawn out and slackened so that the sheet is spread on the electronic component. There is also known one that prevents the occurrence of defective crimping due to self (see, for example, Patent Document 2).

Also, the supply roller and the take-up roller are configured to feed the tape in the required amount, and the tape guide roller is moved by the guide roller moving means so that the tape is slackened in the same manner as described above. It is known (see, for example, Patent Document 3).
Japanese Patent No. 3744503 Japanese Patent No. 3279853 JP 2006-210464 A

  By the way, in recent years, while flat display panels have been increased in size, there has been a strong demand for cost reduction. In the crimping process for crimping electronic components to a substrate, the tact time is shortened and the consumable is expensive. Therefore, it is required to reduce the amount of the tape used as much as possible.

  Therefore, in the configuration in which a tape-like sheet having a width dimension substantially corresponding to the width dimension of the crimping portion is supplied along the longitudinal direction of the side end portion of the panel, it takes time to supply the sheet as the panel is enlarged, and the crimping is performed. Since the tact time becomes long, as described in each of the above-mentioned Patent Documents 1 to 3, a belt-like sheet having a width over the substantially entire length of the side end portion of the panel is supplied to the crimping portion of the side end portion of the panel. In many cases, the sheet feeding apparatus configured as described above is adopted.

  Thus, in the configuration in which the sheet is supplied in a direction orthogonal to the longitudinal direction of the crimping part of the side end portion of the panel, the sheet feed amount for each crimping operation is not only the width dimension of the crimping part, Since deformation occurs due to the thermal effect of the crimping tool that is higher than the heat resistance temperature of the sheet during crimping, it is necessary to feed a length that can reliably avoid the deformed part. Since it is set according to the amount of rotation of the take-up roll 3 by the take-up motor 4, there is an error generation factor such as a change due to a change in the take-up radius of the take-up roll 3, so at least the length is surely secured. In order to send the sheet, the amount of rotation of the winding roll 3 has to be set large with a margin, so that the ratio of the crimping portion in the total area of the sheet becomes very small, the utilization rate of the sheet is low, Since the dose is increased, it is a major impediment against lower costs.

  In view of the above-described conventional problems, the present invention suppresses the sheet feeding amount while shortening the tact time of a crimping process on a large substrate in a crimping apparatus that crimps a component to a substrate via a sheet with a crimping tool. An object of the present invention is to provide a sheet feeding apparatus and method capable of accurately controlling feeding and reducing costs.

  The sheet feeding apparatus according to the present invention feeds a sheet in a direction orthogonal to the longitudinal direction of the component bonding portion so as to be positioned at or near the component bonding portion of the substrate, and the component is bonded to the substrate via the sheet with a crimping tool. A sheet feeding device in a component crimping apparatus that heats and presses the sheet, a sheet winding unit that winds the sheet for a required length for each crimping operation, a sheet slack adjusting unit that adjusts the tension and slack of the sheet, and a sheet Take into account the sheet feed amount by taking into account the sheet feed section wound so that it can be pulled out, the feed amount detection section that detects the feed amount of the sheet, and the sheet feed correction amount due to the sheet pull-out and thermal elongation accompanying the pressing operation of the crimping tool And a control unit that controls a winding amount by the sheet winding unit.

  According to this structure, the sheet feeding time is shortened by feeding the sheet in a direction orthogonal to the longitudinal direction of the component joining portion, and the tact time of the crimping process on a large substrate is shortened. By feeding the sheet in consideration of the sheet feed correction amount due to drawing and thermal elongation, the sheet feed amount can be controlled with high accuracy, and the amount of sheet usage accompanying the sheet feed can be controlled with high accuracy. The feed cost can be reduced.

  In addition, when the control unit resets the detection amount of the sheet feed amount detection unit after the occurrence of an excessive sheet feed amount due to the stop delay of the sheet winding unit and controls the winding amount by the sheet winding unit, the sheet winding unit It is possible to reliably prevent the occurrence of an error in the feed amount due to the variation in the excessive sheet feed amount due to the stop delay of the take section and the integration thereof.

  In addition, if the feed amount detection unit is arranged in the sheet supply unit, it can be detected immediately when a sheet breakage occurs in the sheet supply shaft, and defective products can be detected by continuing production while the recognition of sheet breakage is delayed. Generation and reduction of productivity can be prevented.

  Further, the sheet feeding method of the present invention is a sheet feeding method in which the sheet is fed in a predetermined tension state in a direction perpendicular to the longitudinal direction of the component joint portion of the substrate, and then positioned at or near the component joint portion of the substrate. The part is heated and pressed by the crimping tool to the part joint part of the board through the sheet, and the part is crimped to the board, and the sheet feeding correction amount due to the drawing and thermal elongation of the crimping operation is detected. The sheet after crimping is returned to its original tension state, and the sheet feed amount is controlled by adding the sheet feed correction amount to the predetermined sheet feed amount.

  According to this configuration, while reducing the tact time of the crimping process as described above, the sheet can be fed in consideration of the sheet feeding correction amount due to the drawing and thermal elongation of the sheet during the crimping operation. Therefore, the amount of sheet used can be controlled stably and the cost can be reduced.

  In addition, by resetting the sheet feed detection amount before performing the crimping operation of the crimping tool and feeding the sheet, errors in the feed detection amount are not accumulated, and the sheet is fed with the required minimum amount accurately with each crimping operation. It is possible.

  In addition, by resetting the sheet feed detection amount after feeding an excessive amount of sheet feed due to a delay in stopping the sheet feed, and feeding the sheet, variations in the overfeed amount due to the delay in stopping the sheet feed and errors in the feed amount due to the integration are generated. Can be reliably prevented.

  According to the sheet feeding apparatus and method of the present invention, while shortening the sheet feeding time by feeding the sheet in the direction orthogonal to the longitudinal direction of the component joining portion and shortening the tact time of the crimping process on a large substrate, By feeding the sheet in consideration of the sheet feeding correction amount due to the drawing and thermal elongation of the crimping operation, the sheet feeding amount can be suppressed, the feeding can be controlled accurately, and the cost can be reduced.

  Hereinafter, an embodiment of a sheet feeding apparatus and method according to the present invention will be described with reference to FIGS. In the present embodiment, components such as TCP and FPC are finally pressure-bonded to a panel in a flat panel display (FPD) such as a liquid crystal display device which is an example of a substrate.

  1 and 2, reference numeral 1 denotes a component crimping device, which is supplied in a state where a component 3 such as a TCP is provisionally crimped to the panel 2, and heats and presses the component 3 to perform final crimping on the panel 2. . Specifically, the panel 2 is supplied in a state in which the component 3 is temporarily press-bonded to the side end portion thereof via an anisotropic conductive material (ACF) (not shown) as a bonding material, and the component 3 is heated. -By pressurizing, the component 3 is joined to the panel 2 in the state in which the electrode of the component 3 and the electrode of the panel 2 are electrically connected by an anisotropic conductive material.

  The component crimping apparatus 1 includes a panel transfer device (not shown) that carries the panel 2 into a predetermined position where the final crimping is performed on the panel 2 and carries it out after the final crimping, and a backup stage that supports the crimping portion of the panel 2 from below. 4, a crimping device 5 for co-bonding the panel 2 and the electronic component 3 in cooperation with the backup stage 4, and a belt-like sheet 7 between the crimping head 6 of the crimping device 5 and the electronic component 3 on the backup stage 4. And a sheet feeding device 8 for feeding the sheet. Reference numeral 21 denotes a control unit that controls the operation of each of these devices.

  In the present embodiment, as the sheet 7, the anisotropic conductive material that protrudes at the time of pressure bonding is difficult to adhere, and the polytetrafluoroethylene sheet 7 a absorbs the dimensional variation of the panel 2 and the parts 3, and is in a uniform pressure bonding state. 2 layers of a buffer sheet 7b obtained by laminating a sheet of silicon rubber, which is a material having cushioning properties, and a sheet of polyimide, which is a material having a high heat-resistant temperature, in order to suppress deterioration of physical properties due to heat of the pressure-bonding head 6. The sheets 7a and 7b are used, and the sheets 7a and 7b can be fed in a laminated state and in a required amount separately. Note that the sheet 7 to be used is not limited to this, and depending on the characteristics required by the pressure bonding conditions, any one or a plurality of sheets of various physical properties are used in a stacked state, or these A composite sheet obtained by laminating any one of the above sheets may be used. Further, in order to improve the thermal conductivity from the crimping head 6 to the component 3, a metal foil may be laminated to form a coating layer.

  The thickness of the sheet 7 is preferably about 0.05 to 0.3 mm, and among them, the polytetrafluoroethylene sheet has a thermal conductivity of 0.245 W / (m · K). Since it is low, heat transfer becomes poor when it is thick, so a thin sheet of about 0.05 to 0.1 mm is used. On the other hand, the silicon rubber sheet has a relatively high thermal conductivity of 0.42 W / (m · K), so that heat transfer can be secured even if it is thick to some extent, and 0.2 to 0.2 to obtain a higher cushioning property. A thick sheet of about 0.3 mm is used.

  The backup stage 4 is configured by installing a stage member 4a made of quartz or ceramics on a base part 4b. In the crimping step, the side end of the panel 2 is placed on the upper surface of the stage member 4a, and the crimping head 6 and The side part of the panel 2 and the electronic component 3 are sandwiched between them, and are heated and pressed to perform pressure bonding.

  The crimping device 5 is arranged so that the crimping head 6 faces directly above the backup stage 4, and the crimping head 6 is moved up and down by a head driving unit 10 installed on a gate-shaped frame 9. It is configured. A crimping tool 11 that presses the crimping part of the component 3 through the sheet 7 is attached to the lower end of the crimping head 6, and a heater (not shown) that heats the crimping tool 11 is incorporated.

  The sheet feeding device 8 includes a sheet supply unit 12 disposed on one side of the crimping device 5, a sheet winding unit 13 disposed on the other side of the crimping device 5, and a sheet slack adjusting unit that adjusts the tension and slack of the sheet 7. 14 and sheet slack rollers 15a and 15b that loosen the sheet 7 passed between the crimping tool 11 and the component 3 temporarily crimped to the panel 2 so as to follow the component 3 when the component 3 is crimped. . The sheet supply unit 12, the sheet winding unit 13, and the sheet slack adjustment unit 14 are provided for each of the sheets 7a and 7b, respectively, but have substantially the same configuration. Then, it demonstrates as the sheet | seat 7 (7a and 7b).

  The sheet supply unit 12 is configured to be able to pull out the sheet 7 by rotatably supporting the supply roll 16 around which the sheet 7 is wound while applying a predetermined braking force. In addition, a rotatable roller is brought into elastic contact with the sheet 7 immediately before being pulled out from the supply roll 16, and an encoder is disposed so as to rotate in conjunction with the roller. The feed amount is detected.

  The sheet winding unit 13 includes a winding roll 18 that winds and winds the sheet 7, and a winding motor 19 that rotationally drives the winding roll 18, and the amount of winding the sheet 7 by the feed amount detection unit 17. It is configured to feed the sheet 7 by a predetermined feed amount by rotationally driving the take-up roll 18 while detecting this.

  The sheet slack adjustment unit 14 includes a pair of guide rollers 20a and 20b, and an adjustment roller 20c disposed between the guide rollers 20a and 20b so as to be movable in a perspective direction with respect to the guide rollers 20a and 20b. When the roller 20c is positioned between the guide rollers 20a and 20b, a predetermined slack is generated in the sheet 7, and the sheet 7 is stretched by being positioned at a predetermined distance from the guide rollers 20a and 20b. It is configured to be in a state.

  The sheet slack rollers 15a and 15b are arranged in a state where the sheet 7 is stretched as shown by a solid line in FIG. It is configured to be movable up and down between the descending positions positioned so as to be along, and when positioned at the descending position, the sheet slack adjusting unit 14 causes the sheet 7 to be slack. Reference numerals 22a and 22b are guide rollers disposed in the sheet supply unit 12 of the respective sheets 7a and 7b, and reference numerals 23a and 23b are guide rollers disposed outside the sheet slack rollers 15a and 15b.

  Next, a crimping process for crimping the component 3 to the panel 2 by the component crimping apparatus 1 having the above configuration will be described mainly with reference to an operation flowchart of FIG. 3 and an operation explanatory diagram of FIG.

  3 and 4, first, the panel 2 on which the component 3 is temporarily crimped is carried into the component crimping apparatus 1, and the side end portion of the panel 2 on which the component 3 is temporarily crimped is placed on the backup stage 4 (step S1). ), The count value of the encoder of the feed amount detection unit 17 is cleared (step S2) (see FIG. 4A). Next, the adjustment roller 20c of the sheet slack adjustment unit 14 is moved between the guide rollers 20a and 20b to change the tension state to the slack state (step S3) (see FIG. 4B). Next, the sheet slack rollers 15a and 15b are moved to the lowered position, and the sheet 7 is positioned along the component 3 (step S4) (see FIG. 4C).

  Next, a main pressure bonding operation is performed (step S5) (see FIG. 4D). In the main crimping operation, the crimping tool 11 is lowered, and the crimping operation is performed by heating and pressurizing the component 3 to the panel 2 through the sheet 7 with the crimping tool 11, and then the crimping tool 11 is raised. Next, after the sheet slack rollers 15a and 15b are moved to the raised position (step S6) (see FIG. 4E), the adjustment roller 20c of the sheet slack adjusting section 14 is moved away from the guide rollers 20a and 20b. It is moved to change from the slack state to the tension state (step S7) (see FIG. 4F).

  Next, the panel 2 is taken out from the backup stage 4 and unloaded from the component crimping apparatus 1 (step S8), and the sheet 7 is fed (steps S9 and S10) (see FIG. 4G). In the sheet 7 feeding operation, after the winding motor 19 is rotated so as to feed the sheet 7 by 0.5 mm (step S9), the detected value of the feeding amount of the sheet 7 by the encoder of the feeding amount detection unit 17 is: It is determined whether or not the sheet feed set value is exceeded (step S10), and the above-described feed operation of 0.5 mm is repeated until the detected value of the feed amount of the sheet 7 becomes the sheet feed set value or more. When the detected value of the feed amount is equal to or greater than the sheet feed set value, it is determined whether or not production is completed (step S11). If production is not completed, the process returns to step S1 and the above operations are repeated. It ends as it is.

  In the feeding operation of the sheet 7 described above, at the time of the main press-bonding operation shown in FIG. 4D in step S5, as shown in an enlarged view in FIG. The sheet 7 is pulled out from the sheet supply unit 12 by the total length of the sheet 7 by pulling the sheet 7 as the crimping tool 11 descends while generating thermal elongation. The extracted length is detected by the feed amount detection unit 17, and the detected value is used as a sheet feed correction amount, which is added to the sheet feed set value at the time of the sheet 7 feed operation in the next steps S9 and S10. . By feeding the sheet 7 in this way, the feed amount of the sheet 7 is controlled with high accuracy. Thus, the sheet 7 can be fed with high accuracy in consideration of the length for avoiding the portion affected by the heat by the high-temperature crimping tool 11, and as a result, the amount of use of the sheet 7 is reduced and the cost is reduced. Can be planned.

  Further, when stopping the feeding operation of the sheet 7 in steps S9 and S10, the winding motor 19 cannot be stopped immediately, and the occurrence of a slight overfeed amount cannot be avoided. Therefore, as described above, the encoder count value of the feed amount detection unit is cleared in step S2 so that the excessive feed amount does not affect the sheet feed amount setting value and reduce the accuracy of the feed amount. ing. Note that the process of step S2 may be performed immediately after the processes of steps S9 and S10.

  In addition, when the sheet 7 is replaced or when a sheet feeding unit is used, in order to realize accurate feeding, the gear meshes in the rotational drive system of the take-up roll 18. It is necessary to remove the looseness of the seat and the seat 7. In such a case, as shown in FIG. 6, after starting, it is first determined whether the sheet 7 has been replaced or the sheet feeding unit has been set (step S12), and the determination is affirmative. In this case, it is preferable to rotate the winding motor 19 by an appropriate amount to perform the initial feeding of the sheet 7 (step S13), and then shift to a normal sheet feeding operation.

  The feeding operation of the sheet 7 by the above sheet feeding control is shown in FIG. 7 as a graph in which the vertical axis represents the sheet feeding amount and the horizontal axis represents time. In FIG. 7, the total sheet feed amount setting value is kept constant with high accuracy by detecting the pull-out amount associated with the main crimping operation and correcting the set value of the feed amount when the sheet is fed by the winding motor 19. Has been. The actual feed amount of the sheet 7 is an amount obtained by adding an excessive sheet feed amount due to a stop delay of the winding motor 19 to the set value of the sheet feed amount. Therefore, the excessive sheet feeding amount may be detected by the feeding amount detection unit 17 each time, and the next sheet feeding amount setting value may be decreased and set by the detected amount.

  According to the above embodiment, since the sheet 7 is fed in a direction orthogonal to the longitudinal direction of the joint portion between the component 3 and the panel 2, the sheet feeding time is shortened and the tact of the crimping process in the large panel 2 is achieved. Since the sheet 7 is fed in consideration of the sheet feeding correction amount due to the drawing and thermal elongation of the sheet 7 accompanying the crimping operation, the feeding amount of the sheet 7 can be controlled with high accuracy. As a result, the usage amount of the sheet 7 accompanying the feeding amount of the sheet 7 can be suppressed, and the cost can be reduced.

  In addition, since the detection amount of the feed amount detection unit 17 is reset after the occurrence of an excessive sheet feed amount due to the stop delay of the sheet winding unit 13, the winding amount by the sheet winding unit 13 is controlled. It is possible to reliably prevent variations in the sheet feed amount due to the stoppage delay of the taking section 13 and errors in the feed amount due to the integration.

  Further, since the feed amount detection unit 17 is arranged in the sheet supply unit 12, when the sheet supply unit 12 has run out of sheets, it can be detected immediately at that time, so detection of the sheet cut remains delayed. It is possible to prevent the occurrence of defective products and the decrease in productivity due to continued production.

  In the above description of the embodiment, only the example in which the component 3 such as TCP temporarily bonded to the panel 2 via the anisotropic conductive material is press-bonded has been described, but the present invention can be applied to any substrate. Printed on parts such as TCP and FPC joined to panel crimping equipment and panel 2 for joining by heating and pressurizing electronic parts temporarily fixed through various joining materials such as anisotropic conductive materials and non-conductive joining materials The present invention can also be applied to a component crimping apparatus that joins a substrate by directly crimping (not temporarily crimping) the substrate via an anisotropic conductive material.

  According to the sheet feeding apparatus and method of the present invention, while shortening the sheet feeding time by feeding the sheet in the direction orthogonal to the longitudinal direction of the component joining portion and shortening the tact time of the crimping process on a large substrate, By feeding the sheet in consideration of the sheet feed correction amount due to the drawing and thermal elongation of the crimping operation, the sheet feed amount can be suppressed, and the cost can be controlled accurately and the cost can be reduced. It can utilize suitably for the component crimping | compression-bonding apparatus which crimps | bonds components.

1 is an overall perspective view of an embodiment of a component crimping apparatus to which a sheet feeding device of the present invention is applied. The front view which shows schematic structure of the embodiment. The operation | movement flowchart of the same embodiment. Explanatory drawing of each operation state in the embodiment. Explanatory drawing of the behavior of the sheet | seat at the time of crimping | compression-bonding. In the same embodiment, a flowchart of an initial feeding operation process at the time of sheet replacement. Explanatory drawing of the sheet | seat feeding operation | movement in the embodiment. The schematic block diagram of the sheet feeding apparatus in the crimping | compression-bonding apparatus of a prior art example.

Explanation of symbols

1 Component crimping device 2 Panel (board)
3 Parts 7 Sheet 8 Sheet Feeding Device 11 Crimping Tool 12 Sheet Feeding Unit 13 Sheet Winding Unit 14 Sheet Loosening Adjustment Unit 17 Feed Amount Detection Unit 21 Control Unit

Claims (6)

  Component crimping that feeds a sheet in a direction perpendicular to the longitudinal direction of the component joint so that it is located at or near the component joint on the board, and heats and presses the component to the component joint on the substrate via the sheet with a crimping tool A sheet feeding device in the apparatus, a sheet winding unit that winds a sheet for a required length for each crimping operation, a sheet slack adjustment unit that adjusts the tension and slack of the sheet, and a sheet supply that is wound so that the sheet can be pulled out Part, sheet feed amount detection unit for detecting the sheet feed amount, and sheet take-up amount by the sheet take-up unit taking into account the sheet feed correction amount due to sheet drawing and thermal elongation accompanying pressing operation of the crimping tool And a control unit for controlling the sheet feeding device.   The control unit controls a winding amount by the sheet winding unit by resetting a detection amount of the sheet feeding amount detection unit after occurrence of an excessive sheet feeding amount accompanying a stop delay of the sheet winding unit. The sheet feeding device described.   The sheet feeding device according to claim 1, wherein the feeding amount detecting unit is arranged in the sheet feeding unit.   After feeding the sheet in the direction perpendicular to the longitudinal direction of the component joint part of the board in a predetermined tension, loosen the sheet so that it is located at or near the part joint part of the board, and then use the crimping tool The part is heated and pressed to the part joint part of the board to crimp the part to the board, and the sheet feeding correction amount due to the drawing and thermal elongation of the sheet accompanying the crimping operation is detected, and the sheet after crimping is returned to its original tension state A sheet feeding method characterized in that the sheet feeding amount is controlled by adding a sheet feeding correction amount to a predetermined sheet feeding amount.   The sheet feeding method according to claim 4, wherein the sheet feeding is reset and the sheet feeding detection amount is reset before performing the crimping operation of the crimping tool.   5. A sheet feeding method according to claim 4, wherein the sheet feeding is performed after resetting the detected sheet feeding amount after the occurrence of an excessive sheet feeding amount associated with a delay in stopping the sheet feeding.

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