Leaf feeder and image generation device

Abstract

A leaf conveyor device designed to transport a single leaf, comprising: a skew feed correction section designed to correct a skew feed of a sheet, wherein the skew feed correction section has the following features: a pair of rotating elements designed to transport the sheet; a locking element designed to rest against a guide edge of a sheet being conveyed, and which has a starting position; and a movement element which is provided with a gap between the movement element and the locking element which is positioned in the initial position, such that the locking element can be moved upwards independently of the initial position up to a point of engagement with the movement element when the gap is closed, and such that the movement element can be moved integrally with the locking element while the gap is closed, wherein the pair of rotating elements is arranged to clamp a sheet for a period of time during which the locking element is designed to move integrally with the moving element.

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a sheet feeding device and to an image generating device and in particular to the construction of an inclined feed correction section, which is designed to correct an inclined feed of a sheet. Description of the relevant state of the art

[0002] According to the prior art, an image-generating device, such as a copier, printer, or fax machine, has an image-generating section and a paper feeder designed to transport a sheet of paper to the image-generating section via a feed roller. In the image-generating device according to the prior art, the paper may sometimes be tilted during transport due to deformation or misalignment of the feed roller. In the image-generating device, the position of the paper relative to the image-generating section significantly affects the accuracy of the image position relative to the paper, and consequently, precise alignment of the paper's position relative to the image-generating section is a crucial factor in ensuring image quality.

[0003] In light of the above, the prior art image generation device incorporates a skew-feed correction section on the sheet transport device, and this skew-feed correction section corrects the skew feed of the sheet in order to improve the accuracy of the image generation position. One such skew-feed correction section described above is known, for example, as having a closure that is biased by a spring or the like in a direction opposite to the sheet transport direction, in order to bring a guide edge of the sheet into contact with the closure (published Japanese patent application JP H09-183539 and international patent application WO 2011 / 048668 A).In the skewed feed correction section of the closure type described above, the guide edge of the sheet is brought into contact with a contact section of the closing element, which is positioned perpendicular to the sheet feed direction, and the guide edge of the sheet is aligned with the contact position, thereby correcting the skewed feed of the sheet.

[0004] Furthermore, a requirement has recently arisen among users regarding improved productivity of the image generation device and a reduction in operating noise. However, when the skewed feed is corrected by bringing the sheet into contact with the sealing element, as is the case with the sheet feeder according to the relevant prior art, a collision noise is generated when the guide edge of the conveyed sheet is brought into contact with the sealing element. This collision noise becomes louder when the sheet feed speed is increased to improve productivity.

[0005] Furthermore, US 8 459 642 B2 discloses a sheet conveying device comprising a sheet conveying section, a closing element that rests against a guide edge of a sheet being conveyed to correct a skewed feed of the sheet, a pretensioning element that pretensions the closing element, and a support element that movably supports the closing element so that the closing element can assume different positions. SUMMARY OF THE INVENTION

[0006] The present invention has been made taking into account the aforementioned circumstances, and it is therefore an object of it to provide a sheet conveying device and an image generating device which is designed to reduce the collision noise generated by contact between a sheet and a closure element.

[0007] According to one embodiment of the present invention, the sheet conveying device, which is designed to convey a sheet, is provided with: a skew feed correction section designed to correct a skew feed of a sheet, wherein the skew feed correction section has the following features: a pair of rotating elements designed to transport the sheet; a locking element designed to rest against a guide edge of a sheet being conveyed, and which has a starting position; and a movement element which is provided with a gap between the movement element and the locking element which is positioned in the initial position, such that the locking element can be moved upwards independently of the initial position up to a point of engagement with the movement element when the gap is closed, and such that the movement element can be moved integrally with the locking element while the gap is closed, wherein the pair of rotating elements is arranged to clamp a sheet for a period of time during which the locking element is designed to move integrally with the moving element.

[0008] Further features of the present invention are obvious from the description of exemplary embodiments set out below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows an overall assembly view of a color laser printer, which serves as an example of an image generation device having a sheet feeder according to a first embodiment of the present invention. The Fig. 2A and Fig. Figure 2B shows initial explanatory views of the construction of an inclined feed correction section provided on the leaf feeder. Fig. Figure 3 shows a second explanatory view of the structure of the skew feed correction section. Fig. Figure 4 shows an explanatory view of the locking elements provided in the skew feed correction section. Fig. Figure 5 shows a view of the state at the time when the locking element is positioned in the initial position. Fig. Figure 6 shows a view of the state of a locking cam at the time when the locking element is positioned in the initial position. Fig. Figure 7 shows a view of the state at the time when a slanted sheet is conveyed to the slant feed correction section. The Fig. 8A, Fig. 8B, Fig. 8C and Fig. Figure 8D shows initial explanatory views of a skew feed correction process of the skew feed correction section. The Fig. 9A, Fig. 9B, Fig. 9C and Fig. Figure 9D shows second explanatory views of the skew feed correction process of the skew feed correction section. The Fig. 10A, Fig. 10B, Fig. 10C and Fig. Figure 10D shows third explanatory views of the skew feed correction process of the skew feed correction section. The Fig. 11A, Fig. 11B, Fig. 11C and Fig. Figure 11D shows fourth explanatory views of the skew feed correction process of the skew feed correction section. Fig. Figure 12 shows a cam diagram of a relationship between a position of the locking element, a radius of the locking cam and an angle of the locking cam. Fig. Figure 13 shows a first view of a different design of the skew feed correction section. Fig. Figure 14 shows a second view of a different design of the skew feed correction section. Fig. Figure 15 shows an explanatory view of the construction of an inclined feed correction section provided in a sheet feeder according to a second embodiment of the present invention. The Fig. 16A and Fig. Figure 16B shows initial explanatory views of a skew feed correction process of the skew feed correction section. The Fig. 17A and Fig. Figure 17B shows second explanatory views of the skew feed correction process of the skew feed correction section. The Fig. 18A and Fig. Figure 18B shows views of a different setup of the skew feed correction section. DESCRIPTION OF THE EXAMPLES OF EXECUTION

[0009] Exemplary embodiments of the present inventions are described in detail below with reference to the accompanying drawings. Fig. Figure 1 shows an overall assembly view of a color laser printer, which serves as an example of an image generation device comprising a sheet feeder according to a first embodiment of the present invention. Fig. 1. A color laser printer 600 has a laser printer main body 600A for lasers in all colors (hereinafter referred to as the "printer main body"). The printer main body 600A has an image generation section 600B, which is configured to generate an image on a sheet, a sheet feed section 600C for feeding the sheet, a sheet conveying device 100, which is configured to convey to the image generation section 600B the sheet fed by the sheet feed section 600C, and the like.

[0010] The image generation section 600B has process cartridges 8 (8Y, 8M, 8C, and 8K) which are removable and mounted on the printer main body 600A. It is designed to produce toner images from four colors, specifically yellow, magenta, cyan, and black. In this case, the process cartridges 8 have photosensitive drums 1 (1Y, 1M, 1C, and 1K) which serve as image carriers, charging rollers 2 (2Y, 2M, 2C, and 2K), and developing rollers 3 (3Y, 3M, 3C, and 3K). Furthermore, the image generation section 600B has a scanner unit 4, which is arranged vertically below the process cartridges 8. This scanner unit emits laser beams based on image information to generate electrostatic latent images on the respective photosensitive drums 1.

[0011] Furthermore, in Fig. 1. The printer main body 600A includes an intermediate transmission belt unit 600D, and the intermediate transmission belt unit 600D has an intermediate transmission belt 601 and primary transmission rollers 7 (7Y, 7M, 7C, and 7K) arranged on an inner side of the intermediate transmission belt 601. It should be noted that the intermediate transmission belt 601 is tensioned around a secondary transmission counter roller 602T, a drive roller 6, and a tension roller 5. In this case, the drive roller 6 is a roller designed to drive the intermediate transmission belt 601 in a direction indicated by arrow B (clockwise) such that the surface velocity of the intermediate transmission belt 601 becomes substantially equal to the surface velocity of each photosensitive drum 1. Furthermore, the drive roller 6 is driven by a drive source (not shown).

[0012] Furthermore, the primary transfer rollers 7 are arranged to face the respective photosensitive drums 1 to form primary transfer sections T1 (T1Y, T1M, T1C, and T1K), and a (not shown) biasing unit applies a transfer bias to the primary transfer rollers 7. The primary transfer rollers 7 then apply a primary transfer bias to the intermediate transfer belt 601, and consequently, the toner images of the respective colors on the photosensitive drums 1 are transferred sequentially to the intermediate transfer belt 601. In this way, images with all colors are produced on the intermediate transfer belt 601.Furthermore, the secondary transmission counter roller 602T and a secondary transmission roller 602 form a secondary transmission section T2, which is designed to transfer the images with all colors that were successively generated on the intermediate transmission belt 601 onto the sheets.

[0013] The sheet feed section 600C has a sheet feed cassette 9, which is removablely mounted on the printer main body 600A, and a take-up roller 10, which is designed to feed sheets S contained in the sheet feed cassette 9. The sheet feeder 100 has a sheet separator section 13, which is designed to separate (single) the sheets S fed by the take-up roller 10 into each individual sheet S, and a skew correction section 12, which is designed to correct a guide edge of the sheet S passing through the sheet separator section 13 so that it becomes parallel to a guide edge of an image area that has the toner image on the intermediate transfer belt 601.It should be noted that after correcting the skew feed of the sheet S, the skew feed correction section 12 guides the sheet S into the secondary transfer section T2 synchronously with the time at which the toner images on the intermediate transfer belt 601 arrive at the secondary transfer section T2.

[0014] It should be noted that in Fig. 1. A fuser section 604 fixes the toner images by heating and applying pressure to the images produced on the sheet S. The fuser section 604 has a heating roller 604a and a pressure roller 604b, which is held in pressure contact with the heating roller 604a. Furthermore, a control panel 605, which serves as a control unit, controls the color laser printer 600. Based on a print start signal, the control panel 605 causes yellow, magenta, cyan, and black toner images to be produced on the respective photosensitive drums 1.

[0015] The following describes the image generation process of the 600 color laser printer, which has the setup described above. When image signals are input from a (not shown) personal computer or similar device to the scanner unit 4, the scanner unit 4 irradiates the photosensitive drums 1 with laser beams according to the respective image signals. At this point, the surfaces of the photosensitive drums 1 are uniformly charged beforehand at a predetermined polarity and potential by the charging rollers 2, and electrostatic latent images are generated on the surfaces by the irradiation of the laser beams from the scanner unit 4. Subsequently, these electrostatic latent images are developed and made visible by the developing rollers 3.

[0016] In this 600 color laser printer, the scanner unit 4 first illuminates the photosensitive drum 1Y with a laser beam corresponding to an image signal of a yellow component of an original, thereby generating an electrostatic latent image for yellow on the photosensitive drum 1Y. The developer roller 3Y then develops the electrostatic latent image for yellow with yellow toner, making it visible as a yellow toner image. Subsequently, as the photosensitive drum 1Y rotates, the yellow toner image arrives at the primary transfer section T1Y, which is formed by the connection between the photosensitive drum 1Y and the intermediate transfer belt 601. The yellow toner image on the photosensitive drum 1Y is then transferred to the intermediate transfer belt 601 by the primary transfer bias applied to the primary transfer roller 7Y.

[0017] When a portion of the intermediate transfer belt 601, which carries the yellow toner image, moves, a magenta toner image, generated on the photosensitive drum 1M by a method similar to the one described above, is transferred to the intermediate transfer belt 601 at the time of the belt's movement and superimposed on the yellow toner image. Similarly, as the intermediate transfer belt 601 moves, a cyan toner image and a black toner image are transferred to their respective primary transfer sections T1C and T1K, respectively, and superimposed on the yellow and magenta toner images. In this way, toner images of all colors are generated on the intermediate transfer belt 601.

[0018] Furthermore, in parallel with the toner image generation process, the sheets S contained in the sheet feeder cassette 9 are fed through the take-up roller 10 and then separated into individual sheets S by the sheet separator section 13, which serves as a sheet feeder unit, for conveying. The sheet S is then conveyed to the skew feed correction section 12, and the skew feed is corrected by this section. Finally, the sheet S is conveyed to the secondary transfer section T2 by the skew feed correction section 12 such that the position of the toner images in all colors on the intermediate transfer belt 601 is aligned with the position of the sheet S on the secondary transfer section T2.Then, a positive bias voltage is applied to the secondary transfer roller 602 at the secondary transfer section T2, and consequently, the toner images in all colors are transferred via secondary transfer to the intermediate transfer belt 601 and then to the conveyed sheet S. It should be noted that after the toner images have been transferred to the sheet S via secondary transfer, the toner remaining on the intermediate transfer belt 601 is removed by a transfer belt cleaning device 603, and the removed toner is collected in a waste toner collection container (not shown).

[0019] After the toner images have been transferred to sheet S, the sheet S is conveyed to the fixing section 604 and heated and pressed by the heating roller 604a and the pressure roller 604b so that the toner images in all colors are fixed to the surface of the sheet S as a permanent image. After the toner images in all colors have been fixed as a permanent image, as described above, if an image forms on one side of the sheet S, the sheet S is then delivered by the sheet delivery section 600E and stacked onto a sheet stacking section 600F.In the case of forming images on both sides of the sheet S, the sheet S is conveyed again to the image generation section 600B via a duplex conveying section 600G, and afterwards the images are formed on both sides of the sheet S, and the sheet S is delivered and stacked on the sheet stacking section 600F.

[0020] The Fig. 2A and Fig. Figure 2B shows explanatory views of the construction of the inclined feed correction section 12, which is provided on the leaf feeder 100. Fig. Figure 2A shows a perspective view of the skewed feed correction section 12 and Fig. Figure 2B shows a perspective view of the skewed feed correction section 12 from a side opposite to the side of Fig. 2A. The skewed feed correction section 12 has a pair of positional accuracy rollers 101, 102, which serve as a pair of rotary elements. The positional accuracy roller 101 has a roller shaft 101f arranged parallel to a rotational axis of each photosensitive drum 1, and rotatable conveying elements 102 (102a, 102b, 102c, 102d and 102e). The positional accuracy roller 101 has the roller shaft 101f and a plurality of roller body sections 101a, 101b, 101c, 101d and 101e, which are fixed to the roller shaft 101f at predetermined intervals. Furthermore, the rotatable conveyor elements 102a to 102e are held in pressure contact with the multitude of roller main bodies 101a to 101e of the position accuracy roller 101.

[0021] It should be noted that in the exemplary embodiment, the rotatable conveying elements 102 (102a to 102e) are rotatably supported by bearing sections (not shown) which are supported in such a way that they are movable along one direction of the positional accuracy roller 101 with respect to a conveying frame 201, which serves as a main body of the sheet conveying device 100. Furthermore, the bearing sections (not shown) are connected to the positional accuracy roller 101 by pressure units 501 for the rotatable element and pressure springs 502 for the rotatable element, which are in Fig. 3 are shown, pre-tensioned, and thus the rotatable conveying elements 102a to 102e are brought into pressure contact with the roller main bodies 101a to 101e.

[0022] It should be noted that in Fig. 3 a locking shaft 302, which serves as a moving element, is supported such that it is rotatable (movable) with respect to the transport frame 201 and is parallel to the direction of the axis of rotation of each photosensitive drum 1. As shown in Fig. As shown in Figure 4, the locking shaft 302 rotatably holds a plurality of locking elements (locking sections) 301 (301A, 301B, 301C and 301D). It should be noted that a locking cam 303, designed to determine a position (phase) of each locking element 301, is provided at one end section of the locking shaft 302.

[0023] It should be noted that in Fig. 4. A pressure element 304 is supported such that it is rotatable with respect to the transport frame 201. A cam follower 306 is rotatably supported at a lower end of the pressure element 304. Furthermore, the cam follower 306, which is provided on the pressure element 304, is held in constant pressure contact with the locking cam 303 by a locking spring 305, which is fixed to the transport frame 201. It should be noted that in this embodiment, the locking cam 303, the cam follower 306, and the locking spring 305, which serves as a preloading element, form a preloading unit 12A, which is designed to preload the locking shaft 302.

[0024] It should be noted that, as is the case in Fig. As shown in Figure 3, the locking shaft 302 is provided coaxially to a shaft 102g of each rotatable conveying element 102, which serves as a rotating element of the pair of rotating elements, and the shaft 102g of the rotatable conveying element 102 is supported such that a gap T is formed between the shaft 102g and an outer circumferential surface of the locking shaft 302. Thus, even when the rotatable conveying element 102 is moved, the rotatable conveying element 102 is not brought into contact with the locking shaft 302, and as a result, a preload force for the rotatable conveying element 102 is not applied to the locking shaft 302 by the pressing unit 501 for the rotatable element and the pressing spring 502 for the rotatable element.Thus, even when the rotatable conveying element 102 is pre-tensioned, the rotation of the locking elements 301A to 301D and the locking cam 302, which are integrally mounted with the locking shaft 302, is not hindered.

[0025] As this is in Fig. As shown in Figure 5, regulating elements 401 are provided on the locking shaft 302. These elements serve as contact sections that bear against the plurality of locking elements 301A to 301D provided on the locking shaft 302, thereby regulating the rotation of the locking elements 301A to 301D. Furthermore, the plurality of locking elements 301A to 301D are arranged on the same plane on the locking shaft 302 by means of the respective regulating elements 401. In addition, gaps “g” are formed between the locking elements 301A to 301D and the respective regulating elements 401. Thus, the locking elements 301A to 301D are independently rotatable with respect to the locking shaft 302 by an amount corresponding to a gap angle α between the locking elements 301A to 301D and the respective regulating elements 401. It should be noted that in the exemplary embodiment the spacing angle α is set to 5°.Furthermore, three (or a plurality of) retaining surfaces 301a, 301b and 301c, which bear against the guide edge of the sheet S to hold the sheet S, are provided at regular intervals on a circumferential surface of each closure element 301.

[0026] Fig. Figure 5 shows a state at the time when the locking element 301 is positioned in a ready position (hereinafter referred to as the "starting position"), which is a position of the locking element 301 before the sheet S rests against the locking element 301. At this time, the locking element 301 assumes such a position that any one of the three retaining surfaces 301a to 301c on an upstream side of a gap section N (see Figure 5) is engaged. Fig. 3) of the position accuracy roller pair 101, 102 is positioned in a sheet transport direction. Fig. Figure 6 shows the state of the locking cam 203 at this point in time. The locking cam 303 is brought into pressure contact with the cam follower 306 of the pusher 304, which is biased by the locking spring 305, and consequently the locking element 301 is held in its initial position. The locking cam 303 has the same number of recessed sections 303a as the number of retaining surfaces 301a to 301c. When the cam follower 306 engages one of the recessed sections 303a, the locking shaft 302 and the locking element 301 are positioned in their initial positions.

[0027] In general, the 600 color laser printer can be used, as shown in Fig. As shown in Figure 7, the sheet S, which is fed and conveyed by the sheet feed cassette 9, sometimes reaches the position accuracy roller pair 101, 102 in a position inclined by ΔS relative to the position accuracy roller pair 101, 102. If, in this case, the plurality of locking elements 301, which are fixed to the locking shaft 302, are not provided, the sheet S is conveyed in the inclined position so that it enters the secondary transmission section T2, and consequently the image to be transferred to the sheet S is formed while it is inclined (skew) relative to the sheet S. However, the plurality of locking elements 301, which are fixed to the locking shaft 302, are positioned on the upstream side of the gap section N of the position accuracy roller pair 101, 102 in the sheet conveying direction, and thus the inclination (skewness) of the sheet S can be corrected.

[0028] The following describes a skewed feed correction process of the skewed feed correction section 12, which has the aforementioned structure. First, it is approached as described in Fig. Figure 5 shows a leading-edge guide edge section of the blade S, which is conveyed in the inclined position (oblique position), the holding surface 301a of the closing element 301A, which is positioned on the upstream side of the gap section N of the position accuracy roller pair 101, 102 in the blade conveying direction. At this point, as shown in Fig. 6 shows that, due to the preload force of the locking spring 305, the locking cam 303 is in the initial position, which is the contact position for the guide edge of the leaf S to bear against the retaining surface 301a of the locking element 301A.

[0029] Then, as described in Fig. As shown in Figure 8A, when the guide edge of the leaf S is brought into contact with the retaining surface 301a, the locking element 301A is pressed through the leaf S and rotated in a direction indicated by arrow z1. At this point, the gap (g) “g” is formed between the locking element 301A and the regulating element 401, and consequently, the locking element 301A is rotated by an amount corresponding to the gap angle α to abut the regulating element 401. Thus, the gap (g) “g” is eliminated, and the locking element 301A and the regulating element 401 form the gap angle α between them on the opposite side to that before the rotation. As a result, the rotation is temporarily halted in a position where the retaining surface 301a is positioned as shown by 301a'.At this point, the sliding resistance generated between the locking element 301A and the locking shaft 302 due to the rotation of the locking element 301A is sufficiently smaller compared to the preload force of the locking spring 305, which determines the position of the locking cam 303, and consequently, as shown in . Fig. As shown in Figure 8B, there is no change with regard to the positions of the regulating element 401 and the locking shaft 302.

[0030] When the locking element 301A is rotated, the retaining surface 301a is moved to the position indicated by 301a'. At this point, the retaining surface 301a is positioned on the upstream side of the gap section N of the position accuracy roller pair 101, 102 in the blade conveying direction. When the rotation of the locking element 301A is stopped by the regulating element 401, the blade S receives a reaction force caused by a force for holding the locking cam 301, which is preloaded by the locking spring 305. The preload force of the locking spring 305 is set such that the entire locking element assembly 301 is not rotatable at the moment a locking element 301A is pressed through the blade S, as described above.

[0031] Subsequently, when the leaf separator section 13 conveys the leaf S further, so that it reaches the state that is in Fig. As shown in Figure 8C, the leading edge section of the sheet S, which is conveyed in the inclined position, is conveyed further in a state where it is held by the retaining surface 301a' of the locking element 301A. Subsequently, the trailing edge section of the sheet S, which is conveyed in the inclined position, is held by successive contact with the retaining surfaces 301a of the plurality of locking elements 301B, 301C, and 301D, which are arranged in positions corresponding to the leading edge section of the sheet S. Through this process, the sheet S forms a loop that is curved in a direction indicated by the arrow y.

[0032] The loop of leaf S is on side Sr in Fig. 7, where the sheet S is initially held, is larger than at side Sl, and then has a predetermined size. When the loop has the predetermined size, due to the stiffness of the sheet S, the guide edge of the sheet S is aligned with the holding surfaces 301a' of the locking elements 301A to 301D, causing the sheet S to become parallel to the direction of the axis of rotation of the position accuracy roller pair 101, 102, and the inclination ΔS becomes zero. It should be noted that even if the correction is thus carried out in such a way that the inclination ΔS of the sheet S becomes zero, as is the case in Fig. As shown in Figure 8D, no change occurs in the positions of the regulating element 401 and the shutter shaft 302. That is, the shutter shaft 302 is not rotated.

[0033] When the sheet S with the locking elements 301A to 301D is aligned, a force is applied to rotate the locking elements 301A to 301D and the locking cam 303 around the locking shaft 302 in a direction indicated by arrow z2. Fig. As shown in Figure 9A, this is generated due to the stiffness of the sheet S. Thus, the locking elements 301A to 301D and the locking shaft 302 are rotated as a single unit and moved to a passage position to allow the sheet S to enter the gap section N of the position accuracy roller pair 101, 102.

[0034] After the sheet S has entered the gap section N of the positioning roller pair 101, 102, while the locking elements 301A to 301D are rotating, the sheet S is clamped and conveyed by the positioning roller pair 101, 102, which begins to rotate at a predetermined time. It should be noted that when the locking elements 301 are pressed through the sheet S and the locking shaft 302 rotates integrally with the locking elements 301, the locking cam 303 is also rotated, as shown in Fig. 9B is shown.

[0035] Furthermore, when forming the loop of the blade S, it is desirable to form a larger loop inside a blade conveying path formed by the conveying frame 201 and the conveying guide 202, in order to improve the skew-feed correction performance. Therefore, as shown in Fig. As shown in Figure 9A, it is desirable to provide a large loop formation chamber 902 in a sheet conveying path R, which is formed by the conveying frame 201 and the conveying guide 202, in order to form a predetermined loop. It should be noted that the predetermined loop refers to a loop of the sheet S that is formed inside the loop formation chamber 902 and is partially brought into contact with a conveying guide 801 such that the stiffness of the sheet S is sufficiently increased to push the closing elements 301 upwards.

[0036] Then, as described in Fig. As shown in Figure 9C, together with the transport of the guide edge of the leaf S, which is transported due to the transport force of the position accuracy roller pair 101, 102, the locking elements 301 (301A to 301D) are rotated in a direction indicated by arrow z3. When the locking elements 301 are rotated, a top dead center of the locking cam 303 occurs through a contact point between the locking cam 303 and the cam follower 306, together with the rotation, as shown in Figure 9C. Fig. 9D is shown. When the top dead center of the locking cam 303 passes through the contact point between the locking cam 303 and the cam follower 306, a rotational force is exerted in a direction indicated by arrow z4. Fig. 10A shows that the locking elements 301 are generated by the locking cam 303 and the locking spring 305.

[0037] However, at this point, circumferential surfaces 311b, which serve as contact surfaces for the locking elements 301, are brought into contact with the sheet S being conveyed. In this case, the sheet S has a higher stiffness due to the loop design, and when the circumferential surfaces 311b are brought into contact with the sheet S, which thus has a higher stiffness, the locking elements 301 are stopped without rotation. It should be noted here that even in the state where the locking elements 301 are not rotated, as is the case in Fig. As shown in Figure 10B, the rotational force on the locking cam 303 is applied by the locking spring 305, and consequently the locking cam 303 and the locking shaft 302 are rotated by the locking spring 305. That is, in the present embodiment, the circumferential surfaces 311b of the locking elements 301 are brought into contact with the sheet S being conveyed, such that the locking elements 301 stop. In this way, only the locking cam 303 and the locking shaft 302 are rotated.

[0038] Thus, only the locking cam 303 and the locking shaft 302 are rotated by an amount corresponding to the gap angle (interspace angle) α in a direction indicated by the arrow z5 in Fig. 10C is shown, and they are then stopped by the regulating elements 401 in the state in which the gap angle α is formed. In this way, during the transport of the sheet S, the locking elements 301 are held in such a position that the sheet S is clamped by the circumferential surfaces 311b and the transport guide 202. Furthermore, after rotation by the amount corresponding to the gap angle α, the locking elements 301 are stopped, and consequently the locking cam 303 is stopped in a position that is shown in Fig. 10D is shown and in which the top dead center of the cam 303 passes through the contact point between the locking cam 303 and the cam follower device 306.

[0039] The sheet S is then conveyed further, and a trailing edge of the sheet S passes through the sheet separating section 13. The stiffness of the sheet S then decreases. As the stiffness of the sheet S decreases, the locking elements 301 are gradually moved in a direction indicated by arrow z6. Fig. 11A is shown, together with the locking cam 303 and the locking shaft 302. At this point, the locking cam 303 and the locking shaft 302 are rotated as shown in Fig. 11B is shown.

[0040] When the trailing edge of the sheet S is completely separated from the locking elements 301, as is the case in Fig. As shown in Figure 11C, the locking elements 301 are brought into a state in which their retaining surfaces 301b are in the initial position, ready for aligning a guide edge of a subsequent sheet S. Furthermore, as shown in Figure 11C, the locking elements 301 are brought into a state in which their retaining surfaces 301b are in the initial position, ready for aligning a guide edge of a subsequent sheet S. Fig. As shown in Figure 11D, the locking cam 303 is returned to the state in which the locking elements 301 are held in their initial position due to the preload force of the locking spring 305. Subsequently, each time the sheet S passes through the positioning accuracy roller pair 101, 102, the holding surfaces are successively engaged in the sequence of holding surface 301a, holding surface 301b, holding surface 301c, and holding surface 301a, and the respective holding surfaces hold a guide edge of a newly fed sheet S in order to correct any skewed feeding of the sheet S.

[0041] It should be noted that Fig. Figure 12 shows a representation of a relationship between a position of the locking element 301, a radius of the locking cam 303, and an angle of the locking cam 303, as described above. As shown in the cam diagram of Fig. As shown in the exemplary embodiment 12, when the locking cam 303 is rotated by 75°, the locking cam 303 is adjusted to move to the position corresponding to top dead center. When the locking cam 303 is then rotated a further 45° from the position corresponding to top dead center, the locking element 301 is adjusted to move to its initial position.

[0042] As described above, in the exemplary embodiment, when the guide edge of the sheet S is brought into contact with the holding surface 301a, only the locking element 301 is rotated by an amount corresponding to the gap angle α, while the gap “g” is closed. By rotating only the locking element 301 in the manner described above, it is possible to absorb or reduce a shock received by the skewed feed correction section 12 through the locking element 301. Thus, it is possible to reduce the collision noise generated when the sheet S is brought into contact with the locking element 301.This means that, as in the exemplary embodiment, the regulating element 401 is arranged such that the gap “g” is formed between the regulating element 401 and the locking element 301, and the locking element 301 is brought into contact with the regulating element 401 for a period of time while the locking element 301 is moved from the contact position. Thus, it is possible to reduce the collision noise generated by the contact between the leaf S and the locking element 301.

[0043] Furthermore, in this embodiment, after the locking element 301 is moved to the passage position, the circumferential surface 311b of the locking element 301 is brought into contact with the sheet S, and then the locking element 301 is stopped, but the locking cam 303 and the locking shaft 302 are rotated by an amount corresponding to the gap angle α. When the locking element 301 returns to its initial position through the rotation of the locking cam 303 and the locking shaft 302, the gap angle α is maintained at a constant level. Thus, it is possible to maintain a condition in which, even if a subsequent sheet S is conveyed and brought into contact with the locking element 301, the collision noise generated due to the contact between the sheet S and the skewed feed correction section 12 is constantly reduced.

[0044] Furthermore, in the embodiment described above, a larger loop is formed inside the sheet conveying path R, which is formed by the conveying frame 201 and the conveying guide 202, in order to increase the stiffness S. Thus, even in the case where a sheet with low stiffness is conveyed, such as a sheet with a base weight of 60 g / m², it is possible to increase the stiffness S. 2 or less, it is possible to suppress deformation of the guide edge of the sheet when the sheet collides with the locking element 301, and also to improve the sheet skew feeding correction performance.

[0045] The description above relates to a case in which the regulating element 401 is provided on the locking shaft 302 and the gap (intermediate space) “g” between the locking element 301 and the regulating element 401 is configured such that the locking element 301 can be rotated by an amount corresponding to the gap angle α; however, the present invention is not limited to this. For example, as shown in Fig. As shown in Figure 13, a recessed section 403 is provided in the locking element 301, which is designed such that a gap is formed between the locking element 301 and the locking shaft 302. Furthermore, due to the recessed or flattened section 403, the locking element 301 can be independently rotatable relative to the locking shaft 302 by an amount corresponding to the gap angle α.

[0046] Furthermore, as can be seen in Fig. As shown in Figure 14, a spring or elastic element 901 with a spring property that generates a smaller force than the rotational force produced by the locking spring 305 and the locking cam 303 is provided between the locking element 301 and the regulating element 401. The elastic element 901 pre-tensions the locking element 301 in a direction indicated by arrow z7, and thus, after the locking element 301 has been moved to the passage position, the locking cam 303 and the locking shaft 302 can be reliably rotated by an amount corresponding to the gap angle α. That is, the elastic element 901 is provided between the locking element 301 and the regulating element 401, and thus the gap angle α between the locking element 301 and the regulating element 401 can be reliably maintained after the leaf S has passed through without any deterioration of the leaf skew feed correction function.

[0047] A second embodiment of the present invention is described below. Fig. Figure 15 shows an explanatory view of the construction of a skewed feed correction section, which is provided in a sheet feeder according to the exemplary embodiment. It should be noted that in Fig. 15 the same reference symbols as in Fig. 4 represent the same or corresponding sections.

[0048] In Fig. 15 The rotatable conveying elements 102 (102a to 102e) rotate about a shaft 175 of the rotatable element in a state in which the inner circumferential surfaces of the rotatable conveying elements 102 and the outer circumferential surface of the shaft 175 of the rotatable element are held in contact with each other. Furthermore, the rotatable conveying elements 102 are pressed against the plurality of roller main bodies 101a to 101e of the positional accuracy roller 101 by shaft compression springs 176 of the rotatable element, which are provided at both ends of the shaft 175 of the rotatable element.

[0049] Furthermore, locking elements 171 (171A, 171B, 171C and 171D) are fixed to the locking retaining element 172 at the same phase. In this embodiment, a locking section is composed of the locking elements 171A, 171B, 171C and 171D and the locking retaining element 172. The locking retaining element 172 is rotatably supported by the roller shaft 101f of the positional accuracy roller 101 via a rotary motion regulating element 173 and a roller bearing 174, which serve as motion elements.

[0050] The locking element 172 has a regulating section 172a. As shown in the Fig. 16A and Fig. As shown in Figure 16B, the regulating section 172a and the rotary motion regulating element 173 form the space “g” between them. Furthermore, the locking retaining element 172, i.e., the locking element 171, is independently rotatable with respect to the rotary motion regulating element 173 by an amount corresponding to the gap angle α, which is an angle of the gap “g”. It should be noted that in this embodiment, the gap angle α is set to 5°.

[0051] Furthermore, during a period other than the one in which the sheet S is transported, the position of the locking element 172 is held by the rotary motion regulating element 173 in such a position that a holding surface 171a of the locking element 171 is positioned on the upstream side of the gap section N of the position accuracy roller pair 101, 102 in the sheet transport direction. It should be noted that the rotary motion regulating element 173 is biased in a direction indicated by arrow z8 by a torsion spring 177, which serves as the biasing unit, and the position in the initial position is regulated by a stopper 181.

[0052] The following describes a skewed feed correction process of the skewed feed correction section 12 with the aforementioned setup. First, as is done in Fig. Figure 16B shows the guide edge of the conveyed sheet S with the holding surface 171a of, for example, the closing element 171A, which is in Fig. 16A shows that the multiple locking elements 171A to 171D, which are positioned in the initial position, are brought into contact.

[0053] When the guide edge of the leaf S has been brought into contact as described above, the locking element 171A is pressed through the leaf S and rotated in a direction indicated by arrow z9, together with the locking retaining element 172. When the locking retaining element 172 is rotated by an amount corresponding to the gap angle α, the regulating section 172a abuts the rotational movement regulating element 173, and the regulating section 172a and the rotational movement regulating element 173 form the gap angle α between them on the opposite side to the side before the rotation. As a result, the rotation is stopped in a position in which the retaining surface 171a is positioned at a position indicated by 171a'.

[0054] At this point, the sliding resistance between the roller bearing 174 and the roller shaft 101f, caused by the rotational movement of the locking element 172, is sufficiently smaller compared to the preload force of the torsion spring 177, and consequently, there is no change with respect to the position of the rotational movement regulating element 173. Furthermore, the retaining surface 171a' is positioned on the upstream side of the gap section N of the position accuracy roller pair 101, 102 in the sheet transport direction.

[0055] When the rotational movement of the locking element 172 is stopped by the rotational movement regulating element 173, the leaf S receives a reaction force from the torsion spring 177. The preload force of the torsion spring 177 is set such that the entire locking element 171 is not rotatable at the moment when a locking element 171A is pressed through the leaf S, as described above.

[0056] However, the sheet S is then advanced, and a predetermined loop is formed in the sheet S, as described above. The inclination of the guide edge of the sheet S is then corrected, and the guide edge of the sheet S pushes the locking elements 171 upwards. Thus, the sheet S enters the gap section N of the positioning accuracy roller pair 101, 102 and is advanced by the positioning accuracy roller pair 101, 102.

[0057] When the locking elements 171 are pressed upwards, the locking retaining element 172 is pressed upwards together with the locking elements 171, and furthermore, the rotary motion regulating element 173 is rotated together with the locking retaining element 172 by means of the regulating section 172a of the locking retaining element 172. Thus, during the transport of the sheet S, as described in Fig. Figure 17A shows that the sheet S is transported in a state in which the ends of the locking elements 171 are in contact with the sheet S due to the preload force of the torsion spring 177.

[0058] When the sheet S then passes through the skew feed correction section 12, as shown in Fig. As shown in Figure 17B, due to the preload force of the torsion spring 177, the rotary motion regulating element 173 is moved in a direction opposite to the direction of movement in order to return to the initial position, as shown in Figure 17B. Fig. Figure 16A shows this. It should be noted that in this embodiment, the center-of-gravity positions (centers of gravity) of the locking element 172 and the locking elements 171 are fixed on the side of the gap section N instead of at the center of the roller shaft 101f of the position accuracy roller 101. Therefore, when the rotary motion control element 173 returns to its initial position, the locking element 172 and the locking elements 171 return to their initial position due to their own weights and the rotational force generated by the torsion spring 177, while the gap angle α is formed. That is, when the sheet S passes through the locking elements 171, the rotary motion control element 173 is moved due to the preload force of the torsion spring 177, while the locking elements 171 are moved in a direction opposite to the direction of movement.

[0059] As described above, in the exemplary embodiment, after the guide edge of the sheet S has been brought into contact with the holding surface 171a, only the locking element 172, i.e., the locking element 171, is rotated by an amount corresponding to the gap angle α before the skew-feed correction process has been initiated. The rotational movement of the locking element 172, as described above, makes it possible to absorb a shock received by the skew-feed correction section 12 by means of a mediation of the locking element 171 from the guide edge of the sheet S, which is conveyed through the sheet separating section 13. Thus, it is possible to reduce a collision noise that is generated when the sheet S is brought into contact with the locking element 171.

[0060] It should be noted that the description above refers to the case in which the locking retaining element 172 (locking element 171) is rotated about a pivot point corresponding to the roller shaft 101f of the positioning accuracy roller 101; however, the present invention is not limited to this. The locking retaining element 172 (locking element 171) can be rotated about a pivot point corresponding to the shaft 175 of the rotatable element of the rotatable conveying element 102. That is to say, it is only necessary that the locking retaining element 172 (locking element 171) is designed to be rotatable about any of the shafts of the positioning accuracy roller pair 101, 102.

[0061] Furthermore, as can be seen in Fig. As shown in Figure 18A, a spring or elastic element 231 with a spring property that generates a lower spring force than the force of the torsion spring 177 and biases the regulating section 172a in a direction indicated by arrow z10 is provided between the regulating section 172a of the locking element 172 and the rotary motion regulating element 173. Thus, the gap angle α between the locking element 172 and the rotary motion regulating element 173 can be reliably maintained after the leaf S has passed through without impairing the leaf skew feed correction function.

[0062] Furthermore, as this can be seen in Fig.As shown in Figure 18B, the locking element 171 is designed to be movable by an amount corresponding to a gap distance 402c with respect to the locking retaining element 172, and the locking retaining element 172 can be directly pre-tensioned by the torsion spring 177. Thus, when the guide edge of the leaf S rests against the retaining surface 171a, only the locking element 171 is moved by the amount corresponding to the gap distance 402c, and consequently, the effect of reducing the collision noise can be achieved. It should be noted that in this design, the locking retaining element 172 serves as the moving element.

[0063] In this embodiment, the moving element, which is integrally movable with the locking element, is arranged such that a gap (space) is formed between the moving element and the locking element, and this gap is closed during the period when the locking element moves from the contact position to the passage position. This reduces the collision noise generated by the contact between the sheet and the locking element.

[0064] While the present invention is described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims corresponds to the broadest interpretation and includes all variations and equivalent structures and functions.

[0065] The sheet conveying device has: the skew feed correction section, which is designed to correct a skew feed of a sheet, wherein the skew feed correction section comprises: a pair of rotating elements designed to convey the sheet; a locking element designed to bear against a guide edge of the sheet being conveyed and which has a home position; and a moving element provided with a gap formed between the moving element and the locking element, which is positioned in the home position, such that the locking element is movable upwards to an engagement point with the moving element, regardless of the home position, while the gap is closed, wherein the pair of rotating elements is designed to clamp a sheet for a period of time during which the locking element is designed to move in conjunction with the moving element.

Claims

[1] A leaf conveying device designed to convey a leaf, comprising: a skew feed correction section designed to correct a skew feed of a sheet, wherein the skew feed correction section has the following features: a pair of rotating elements designed to transport the sheet; a locking element designed to rest against a guide edge of a sheet being conveyed, and which has a starting position; and a movement element which is provided with a gap between the movement element and the locking element which is positioned in the initial position, such that the locking element can be moved upwards independently of the initial position up to a point of engagement with the movement element when the gap is closed, and such that the movement element can be moved integrally with the locking element while the gap is closed, wherein the pair of rotating elements is arranged to clamp a sheet for a period of time during which the locking element is designed to move integrally with the moving element. [2] A sheet conveying device according to claim 1, which further comprises a pretensioning unit constructed in such a way as to pretension the moving element so that the gap between the moving element and the closing element is maintained during a period of time in which the closing element is moved from a position at a time when the sheet is clamped by the pair of rotating elements to the initial position in which the closing element is arranged to bear against the following sheet being conveyed. [3] A sheet conveying device according to claim 1, wherein the moving element has a closing shaft which is provided coaxially to a shaft of a rotating element of the rotating element pair, and wherein the closing shaft has an engagement section which is designed to engage with the closing element, and wherein during a period of time in which the closing element is pressed through the sheet and moved from the starting position, the closing element is engaged with the engagement section, thereby closing the gap, and during a period of time in which the closing element is moved to the starting position which is designed to bear against a subsequent sheet being conveyed, the engagement section is separated from the closing element to form the gap. [4] A leaf conveying device according to claim 3, which further comprises a preloading unit constructed in such a way as to apply a preload force to the closure shaft such that, after the guide edge of the leaf has been clamped by the pair of rotating elements, the closure shaft is rotated in the same direction as a direction in which the closure element is pressed and rotated by the leaf, wherein, after the guide edge of the leaf has been clamped by the pair of rotating elements, the closure shaft is rotated due to the preload force of the preloading unit in order to form the gap. [5] Leaf conveying device according to claim 4, wherein the closure element comprises: at least a holding surface designed to hold the guide edge of the sheet; and a mounting surface designed to rest against the surface of the sheet that is clamped by the pair of rotating elements, and wherein, after the guide edge of the leaf has been clamped by the pair of rotating elements and before the contact surface rests on the surface of the leaf that is clamped by the pair of rotating elements, the locking shaft is rotated by the preload force of the preload unit to form the gap. [6] Leaf conveying device according to claim 4, wherein the pretensioning unit comprises: a cam that is provided on the locking shaft; a cam follower device provided in a frame element; and a preload element designed to bring the cam follower device into pressure contact with the cam. [7] Leaf conveying device according to claim 3, wherein the closing element has a plurality of closing elements provided on the closing shaft, wherein the plurality of closing elements are movable by an adjacent leaf. [8] Leaf conveying device according to claim 1, further comprising: a pre-tensioning unit designed to pre-tension the moving element to a starting position; and a stopper designed to rest against the moving element in the starting position, wherein the locking element is pressed through the sheet and is moved integrally with the movement element against a preload force of the preloading unit, and where, after the leaf has passed the locking element, the moving element is moved to the starting position in a direction opposite to any direction of a previous movement, due to the preload force of the preload unit, until the moving element rests against the stopper. [9] Leaf conveying device according to claim 8, wherein, when the moving element is positioned in the starting position, the gap is maintained by the weight of the closing element. [10] Sheet conveying device according to claim 2, wherein the closing element corrects the inclined feed of the sheet by the preload force of the preload unit, which is exerted on the at least one holding surface by the movement element. [11] Leaf conveying device according to claim 1, which further comprises an elastic element that is provided between the closing element and the moving element in such a way that it maintains the gap. [12] Imaging device with: an image generation section; and a sheet conveying device according to one of claims 1 to 5, which is constructed in such a way that it conveys a sheet to the image generation section. [13] A leaf conveying device designed to convey a leaf, comprising: a closure section comprising a plurality of closure elements arranged in a direction intersecting with a sheet conveying direction, and constructed to abut a guide edge of a sheet conveyed in such a way that the plurality of closure elements can be pressed and rotated through the sheet; and a movement element which is constructed in such a way that it rotates with the closure section, wherein the movement element has an engagement section which is provided with a gap which is formed between the engagement section and the closure section in a direction of rotation of the plurality of closure elements in which the plurality of closure elements are pressed through the sheet. [14] A sheet conveying device according to claim 13, which further comprises a positioning section configured to position the moving element in a starting position at a time when the guide edge of the sheet being conveyed is in contact with the plurality of closing elements, wherein the positioning section comprises: a cam that is provided on the moving element and has a recessed section formed on the cam; a cam follower device that is kept in contact with the cam in order to be able to engage with the recessed section; and a pre-tensioning unit designed to pre-tension the cam follower device to the cam. [15] Leaf conveying device according to claim 13, which further comprises a positioning section designed to position the moving element in a starting position at a time when the guide edge of the leaf is in contact with the plurality of closing elements, the positioning section has the following features: a stopper that is kept in contact with the moving element; and a pre-tensioning unit designed to pre-tension the moving element towards the stopper.

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