JP2006240821A - Meandering prevention mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small meandering prevention mechanism not depending on a paper feeder, having a simple structure and also applicable to thin paper. <P>SOLUTION: This meandering prevention mechanism provided in a carrying device 4 for carrying long paper 2 applies tension by hanging the long paper 2 over a plurality of rollers 17, 18, 19, 20, 21, 22 sequentially, and guides the end of the long paper 2 of which apparent synthesis is enhanced by the tension by means of guides 25, 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a meandering prevention mechanism used for transporting long paper.

  In an image forming apparatus that prints on continuously supplied long paper (web), it is necessary to prevent meandering so that the long paper does not shift laterally in the width direction. 2. Description of the Related Art Conventionally, a long paper reel is positioned in the width direction by a paper feeding device, and the long paper is prevented from meandering by applying a large tension to the long paper until it passes through the printing unit. However, it is difficult to position the supply device, which requires work time and consumes paper for test printing, which is uneconomical. In addition, it is necessary to produce the paper feeding device in accordance with the image forming apparatus, and there is a problem that the versatility is lacking.

  In Patent Document 1, meandering prevention means for positioning the paper in the width direction by sandwiching the paper with a pair of rollers inclined with respect to the conveyance direction, meandering in a predetermined direction, and pressing the end of the paper against the guide. Is described. In this meandering prevention means, since the end of the paper is pressed against the guide, there is a problem that the thin paper or the paper with low stiffness is deformed or damaged.

In Patent Document 2, the edge of the paper is detected by a detector, and a roller for guiding the paper is inclined according to the position of the paper edge to create a difference in the tension at both ends of the paper. A rotary press having a meandering correction mechanism for returning a sheet to an appropriate position by causing the sheet to be printed is described. However, this meandering correction mechanism is large in size and difficult to downsize.
Japanese Patent Laid-Open No. 8-119504 JP-A-9-109359

  In view of the above problems, an object of the present invention is to provide a small meandering prevention mechanism that can be applied to thin paper with a simple configuration without depending on a paper feeding device.

  In order to solve the above-described problems, according to the present invention, the meandering prevention mechanism provided in the transporting device that transports the long paper sequentially passes the long paper over a plurality of rollers, and the end of the long paper is guided by the guide. I will guide you.

  According to this configuration, it is possible to increase the rigidity of the apparent paper edge by applying tension by suspending the long paper to the plurality of rollers. By guiding the edge of the paper having increased rigidity in this way with the guide, even the thin paper or the weak paper can be regulated so as not to meander with the guide without damaging the paper. Since the apparent rigidity of the paper is higher when the paper is wound around the roller, the guide is preferably provided on the roller.

  The meandering prevention mechanism of the present invention may have a rotation control means for controlling at least one rotation speed of the plurality of rollers.

  According to this configuration, the higher the rotation of the roller, the smaller the tension of the paper after the roller, so that the tension applied to the paper can be adjusted to an appropriate value according to the type of the paper. For this reason, meandering can be prevented without damaging the paper.

  In the meandering prevention mechanism of the present invention, at least one of the plurality of rollers may have a conical shape.

  According to this configuration, since the paper tends to be biased toward the side where the diameter of the conical roller is small, the paper can be positioned by providing the guide on the side where the diameter of the roller is thin. In addition, when the conical roller is used, tension is concentrated only on one end of the paper or twisting occurs in the paper, but the two conical rollers opposite to each other are used to cancel out the force concentration and twisting of the paper, By making a difference in the tension of the paper in each conical roller, a difference can be provided in the force with which the paper is deflected. As a result, the sheet is deflected to the smaller diameter side of the conical roller having the larger tension while the sheet is supplied straight with a uniform tension in the width direction, thereby enabling positioning by the guide.

  As described above, the meander-preventing mechanism according to the present invention increases the apparent rigidity by passing the paper over a plurality of rollers, so that even a thin paper or a weak paper can be regulated so as not to meander by the guide. Further, since tension is applied to the paper in the meandering prevention mechanism, it is not necessary to position the paper feeding device accurately without depending on the paper feeding device.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 1 having a meandering prevention mechanism according to a first embodiment of the present invention. The image forming apparatus 1 is an electrophotographic image forming apparatus that forms and fixes a toner image on a long paper (paper) 2 supplied by a reel. The sheet 2 is sent out from the sheet feeding device 3, and the conveyance supply device 4 sends the sheet 2 into the image forming apparatus 1 at a predetermined speed. The paper feeding device 3 rotates the reel of the long paper 2 and feeds the paper 2 to such an extent that no tension is exerted between the paper feeding device 3 and the conveyance supply device 4. The image forming measure 1 has photoreceptors 5, 6, 7, and 8 capable of forming toner images of respective colors of yellow, magenta, cyan, and black, and formed on the photoreceptors 5, 6, 7, and 8, respectively. The toner image is transferred to the transfer belt 9 and transferred from the transfer belt 9 to the paper 2 in the secondary transfer unit 10. The sheet on which the toner image is transferred is conveyed by the suction belt 11, and the toner image transferred onto the sheet 2 is heated by the preliminary fixing device 12 and the main fixing device 13 and fixed to the sheet 2. The sheet 2 on which the image is thus formed is discharged from the discharge unit 14.

  FIG. 2 shows the conveyance supply device 4 in detail. The conveyance supply device 4 includes an introduction roller 16, a first tension roller 17, a second tension roller 18, a third tension roller 19, a fourth tension roller 20, a fifth tension roller 21, a sixth tension roller 22, and a frame 15. Supply rollers 23 and 24 are all provided in parallel. The introduction roller 16 and the first to sixth tension rollers 17, 18, 19, 20, 21, and 22 each have a hook-shaped reference guide 25 fixed at one end, and the other end according to the width of the sheet width 2. A restriction guide 26 that is movable in the axial direction is provided. The introduction roller 16 can freely rotate, and the first to sixth tension rollers 17 to 22 each have a built-in motor and are rotatable at an arbitrary speed. Supply rollers 23 and 24 are in close contact with each other and are rotated by a motor 27. The first to sixth tension rollers 17 to 22 constitute a meandering prevention mechanism for preventing meandering (lateral deviation) of the paper by the reference guides 25 and the regulation guides 26.

  FIG. 3 shows a conveyance path of the paper 2 in the conveyance supply device 4. The paper 2 supplied from the paper feeding device 3 is first turned back by the introduction roller 16 and, in order, the first tension roller 17, the second tension roller 18, the third tension roller 19, the fourth tension roller 20, and the fifth. It is wound around the tension roller 21 and the sixth tension roller 22 so as to be folded. Further, the sheet 2 is sandwiched between the supply rollers 23 and 24 and fed into the image forming apparatus 1 at a predetermined speed.

  In the transport and supply device 4, the paper 2 tends to be laterally shifted (meandering) in the width direction due to axial variations in the pressing force of the supply rollers 23 and 24 and other factors. By meandering with the guide 25 and the regulation guide 26, meandering is prevented. At this time, if the apparent rigidity of the end portion of the sheet 2 is not sufficient, the sheet is bent or damaged.

  FIG. 4 generally shows the apparent rigidity of the paper edge when the paper is wound around a roller in relation to the amount of wrapping (folding angle) and the tension applied to the paper. Regardless of the amount of wrapping, the greater the paper tension, the higher the stiffness of the paper edge. However, when the wrapping amount is 0 (no folding), the stiffness increases linearly as the tension increases, When wound around a roll, the rigidity increases greatly only by applying a slight tension, and when the tension is further increased, the rigidity starts to increase linearly. That is, the apparent rigidity of the paper edge increases as the amount of winding increases, but the difference becomes more pronounced particularly when a small tension is applied. From this, the apparent rigidity is greatly increased by applying tension while winding the paper around the roller and turning it back. If the paper edge is guided by the guide in this state, the paper meanders without damaging the paper. It can be seen that (lateral shift) can be prevented.

  Next, FIG. 5 shows the relationship between the tension applied to the paper and the number of rollers to be passed (number of times of folding) when the paper is passed over a freely rotating roller and conveyed. The case of high-quality paper) and the case of thin paper (high-quality paper having a thickness of about 0.1 mm) will be described. In this case, it can be seen that the greater the number of rollers and the greater the number of times of folding, the higher the tension, and the thicker the paper, the higher the tension. This means that when the guides are brought into contact with each other in order to prevent meandering, the tension becomes lower as the thin paper should be given higher tension to increase the apparent rigidity.

  FIG. 6 shows the relationship between the tension of the paper and the diameter of the roller. As the roller diameter increases, the tension of the thick paper decreases and the tension of the thin paper increases, but the tension of the thin paper does not become higher than that of the thick paper. In addition, adopting a roller having a large diameter means an increase in the size of the apparatus.

  FIG. 7 shows the relationship between the distance between the rollers for transferring the paper and the tension. This figure shows that the tension increases as the distance between the rollers decreases. Further, this characteristic is not different depending on the type (thickness) of the paper.

  FIG. 8 shows the relationship between the amount of wrapping around the roller (turnback angle) and the tension of the paper. From the figure, it can be seen that the type (thickness) of the paper does not cause a difference in the characteristics of changes in tension depending on the amount of winding around the roller.

  FIG. 9 shows the relationship between the surface roughness of the roller and the tension of the paper. It can be seen that the rougher the surface of the roller, the higher the tension of the paper, but the degree is not related to the thickness of the paper.

  FIG. 10 shows a change in tension when rotation is applied to the roller around which the paper is wound. It can be seen that the tension of the sheet decreases linearly as the rotational speed of the roller increases. Also in this characteristic, there is no difference due to the thickness of the paper. In the figure, “stop” of the roller rotation speed is a state in which the roller is fixed so as not to rotate at all, and the sheet is conveyed while sliding on the roller surface. “Following” is a state in which the speed of the roller surface coincides with the speed of the paper, and there is no slip of the paper with respect to the roller.

  5 to 10, in order to prevent meandering without damaging the paper, the number of rollers, the diameter of the rollers, the distance between the rollers, the amount of winding around the rollers, the surface roughness of the rollers, and the rotation of the rollers It has been found that at least one of the speeds may be changed according to the type (thickness) of the paper. Needless to say, it is apparent that the tension increases as the width of the sheet increases. Therefore, in the present invention, the rotational speed of the rollers (first to sixth tension rollers 17 to 22) that do not require mechanical parts replacement is changed according to the type and width of the paper.

Based on the above basic characteristics, meandering prevention in the first embodiment of the present invention will be described. Here, in FIG. 3, the tension of the sheet 2 between the introduction roller 16 and the first tension roller 17 is T ₀ , and the tension of the sheet 2 between the first tension roller 17 and the second tension roller 18 is T _1. Similarly, between the second and third tension rollers 18 and 19, between the third and fourth tension rollers 19 and 20, between the fourth and fifth tension rollers 20 and 21, and between the fifth and sixth tension rollers 21 and 22. And the tension of the sheet 2 between the sixth tension roller 22 and the supply rollers 23 and 24 are T ₂ , T ₃ , T ₄ , T ₅ , and T ₆ , respectively.

As shown in FIG. 5, the tension of the sheet 2 increases according to the number of wound rollers, and therefore, in the supply device 4, T ₀ <T ₁ <T ₂ <T ₃ <T ₄ <T ₅ <T _Six relationships hold. In order to supply the sheet 2 from the supply rollers 23 and 24 to the inside of the image forming apparatus 1 without meandering in the conveyance supply device 4, the reference guide 15 in the sixth tension roller immediately before the supply rollers 23 and 24. The guide (positioning) by the regulation guide 26 is the most important. Therefore, the value of the tension T ₆ may be increased to such an extent that the apparent rigidity of the end portion of the sheet 2 is not damaged by contact with the reference guide 15 and the regulation guide 26. Here, it must also be considered that the slip also the supply roller 23 and 24 tension T ₆ is too large can not be stable transported or generated.

  According to the transport and supply device 4 of the present embodiment, the rotation speeds of the first to sixth tension rollers 17, 18, 19, 20, 21, and 22 are in accordance with the table of FIG. Rotation control means (not shown) for changing the output of the tension rollers 17 to 22 to the built-in motor is provided. “Over-rotation” in the table means that the tension roller rotates faster than the conveyance speed of the paper 2.

  In the present embodiment, when the sheet 2 having a thickness of 0.05 mm and a width of 4 inches is passed through the conveyance supply device 4, the third tension roller 19 and the fifth tension roller 21 are “driven” (the conveyance speed of the sheet 2 is increased). The other four tension rollers 17, 18, 20, and 22 are "stopped" (fixed without rotating). As a result, a large tension can be applied against the thinness and width of the paper 2, and the paper 2 can be damaged even if the paper ends abut against the reference guide 25 and the regulation guide 26 by increasing the apparent rigidity. You can avoid it.

When supplying paper 2 having a thickness of 0.2 mm and a width of 12 inches or a thickness of 0.3 mm and a width of 4 inches, all the tension rollers 17 to 22 are “driven”, but this condition is supported by a bearing. Same conditions as realized by the roller. Also in this case, a tension T ₆ is generated so that the apparent rigidity of the paper 2 in the sixth tension roller 22 is appropriate.

When supplying a sheet 2 having a thickness of 0.3 mm and a width of 12 inches, only the first tension roller 17 is “driven” and the other tension rollers 18 to 22 are “over-rotated” (rotated faster than the sheet 2). in, it is possible to suppress as tension T ₆ is not too high.

As described above, the supply device 4 according to the present invention appropriately adjusts the tension T ₆ according to the type of the paper 2 and guides it with the reference guide 25 and the regulation guide 26 so as not to damage the paper 2. Acts as

  When the conveying speed of the paper 2 is changed in the supply device 4, the tension acting on the paper 2 increases or decreases. For example, if the transport speed of the paper 2 is decreased, the tension acting on the paper 2 is reduced. Therefore, when supplying the thin paper 2, one of the tension rollers is “reversed” (rotated in the direction opposite to the transport direction of the paper 2). ) May need to be made. In addition, the types of paper are classified not only by thickness and width but also by various elements, and various characteristics relating to tension are also available. Therefore, the rotation speed of the tension rollers 17 to 22 is preferably set by adjusting the appropriate combination for each model number of the long paper 2. Further, the rotation speeds of the tension rollers 17 to 22 may be controlled in more stages. Further, since the behavior of the paper 2 varies depending on the storage conditions and the temperature and humidity during operation, it is desirable to set with a certain margin. Nevertheless, in consideration of the possibility of high tension that causes slippage in the supply rollers 23 and 24, a roller having a torque limiter may be provided.

  The transport and supply device 4 according to the first embodiment regulates the sheet 2 between the reference guide 25 and the restriction guide 26, and a slight meander between the reference guide 25 and the restriction guide 26 is allowed. Accordingly, FIG. 12 shows a transport and supply device 4 ′ according to the second embodiment in which one end of the paper is more positively matched with the reference guide 25. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the third tension roller 19 ′ has a conical shape in which the regulation guide 26 side is narrowed, and the fourth tension roller 20 ′ has a conical shape in which the reference guide 25 side is narrowed. The reference guide 25 is not provided on the third tension roller 19 ′ and the fourth tension roller 20 ′, and the regulation guide 26 is provided only on the introduction roller 16 and the first tension roller 17.

  Further, FIG. 13 shows a conveyance path of the paper 2 in the conveyance supply device 4 ′. When the paper 2 is passed through the transport and supply device 4 ′, the path of the paper end on the small diameter side becomes shorter than the path of the paper end on the large diameter side in the third tension roller 19 ′ and the fourth tension roller 20 ′. For this reason, the tension on the small-diameter side becomes smaller than the tension on the large-diameter side, and the paper 2 tends to move toward the side where the tension becomes smaller. Since the third tension roller 19 ′ and the fourth tension roller 20 ′ have the same conical shape that is different only in direction, if they pass through the third and fourth tension rollers 19 ′ and 20 ′, they are conveyed at both ends of the sheet 2. The paths have the same length, and there is no possibility of bumping at one end of the sheet 2.

However, as described in the first embodiment, the tension of the paper increases every time the paper is folded back by the tension rollers 17 to 22. For this reason, the force that moves the paper 2 in the small diameter direction in the third tension roller 19 ′ and the fourth tension roller 20 ′ is larger than the force in the subsequent fourth tension roller 20 ′. Therefore, as schematically shown in FIG. 14, the sheet 2 tends to move to the small diameter side of the fourth tension roller 20 ′, and the end of the sheet is pressed against the reference guide 25. By selecting a combination of rotational speed of each tension roller 17 to 22, as well as optimizing the tension T ₆ in the sixth tension roller 22 as in the first embodiment, the force that the sheet 2 is deflected to the reference guide side The size can be adjusted.

  The regulation guide 26 of the present embodiment is intended to roughly position the paper 2 supplied from the paper feeding device 3, and the distance from the reference guide 25 is fixed at a position where there is room for the width of the paper 2. do it.

  In this embodiment, two conical rollers are used. However, if the conveyance lengths at both ends of the paper are not excessively different, only one conical roller may be used, and a plurality of rollers having different conical angles. It is also possible to realize the same action using. In addition, the roller can be attached with an inclination.

1 is a schematic view of an image forming apparatus having a conveyance supply device including a meandering prevention mechanism according to the present invention. The perspective view of the conveyance supply apparatus of FIG. FIG. 3 is a schematic diagram illustrating a sheet conveyance path in the conveyance supply apparatus of FIG. 2. The graph which shows the relationship between the tension | tensile_strength of paper and the rigidity of a paper edge part. The graph which shows the relationship between the number of rollers, and the tension | tensile_strength of paper. The graph which shows the relationship between the diameter of a roller, and the tension | tensile_strength of paper. The graph which shows the relationship between the distance between rollers, and the tension | tensile_strength of paper. The graph which shows the relationship between the amount of winding around a roller, and the tension | tensile_strength of paper. The graph which shows the relationship between the surface roughness of a roller, and the tension | tensile_strength of paper. The graph which shows the relationship between the rotational speed of a roller, and the tension | tensile_strength of paper. The table | surface which shows the setting of the roller rotational speed of the conveyance supply apparatus of FIG. The perspective view of a conveyance supply apparatus provided with the meandering prevention mechanism of 2nd Embodiment of this invention. Schematic which shows the conveyance path | route of the paper in the conveyance supply apparatus of FIG. FIG. 13 is a schematic diagram illustrating a state of paper conveyance in the conveyance supply device of FIG. 12.

Explanation of symbols

1 Image forming apparatus 2 Paper (long paper)
4, 4 'transport supply device 17 first tension roll 18 second tension roll 19, 19' third tension roll 20, 20 'fourth tension roll 21 fifth tension roll 22 sixth tension roll 25 reference guide 26 regulation guide

Claims (3)

In the meandering prevention mechanism provided in the transport device for transporting long paper,
Sequentially pass long paper to multiple rollers,
A meandering prevention mechanism characterized in that the end of a long sheet is guided by a guide.   The meandering prevention mechanism according to claim 1, further comprising a rotation control unit that controls at least one rotation speed of the plurality of rollers.   The meandering prevention mechanism according to claim 2, wherein at least one of the plurality of rollers has a conical shape.

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