JP2011006190A - Sheet carrying device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of corner folding of a sheet tip part and a collision flaw of the paper edge.SOLUTION: A sheet carrying means for carrying a sheet has a driving part for driving the sheet carrying means. A butting part guides one end in the sheet carrying right-angled direction to an obliquely sending-carrying mechanism of the sheet, and is rocked by controlling an angle of a left registration butting part in response to a sheet turning quantity when obliquely sending and carrying so that a landing part becomes parallel to the paper edge, and a landing shock of the sheet to the butting part is moderated by being dispersed over the whole paper edge.

Description

  The present invention relates to an image forming apparatus of, for example, a printer, a facsimile machine, a copying machine, or a complex machine having these functions.

  The image forming apparatus includes a plurality of systems such as an electrophotographic system, an offset printing system, and an ink jet system. Here, a color image forming apparatus using the electrophotographic system will be described as an example, and a conventional technique will be described. . The color image forming apparatus mainly includes a tandem method in which a plurality of image forming units are arranged side by side, a rotary method in which the image forming unit is arranged in a cylindrical shape, and a transfer method in which a toner image is directly transferred from a photosensitive member directly to a sheet material. The transfer method and the intermediate transfer method in which the image is once transferred to an intermediate transfer member and then transferred to a sheet material are classified. FIG. 10 is a cross-sectional view of an intermediate transfer tandem type image forming apparatus in which four color image forming units are arranged side by side on an intermediate transfer belt. In recent years, even in such an electrophotographic apparatus, an apparatus aimed at a printing market with a small number of copies has been provided by taking advantage of not making a plate. However, in order to be accepted in such a light printing market, it is necessary to achieve high image quality, and as one of the factors, image position accuracy with respect to paper is emphasized. The image position accuracy includes a front-back shift when a double-sided image is formed.

  For the purpose of improving the image position accuracy with respect to the paper, if factorization is performed, the image position accuracy is determined by registration in the conveyance direction, registration in the direction orthogonal to the conveyance direction, magnification, and skew. Of these, it is difficult to correct only the skew by electrical control. For example, it is possible to correct the image position with respect to the sheet by detecting the skew of the sheet and creating an image inclined in accordance with the skew, but particularly in the case of a color image in which three or four colors are superimposed. If the image is tilted for each sheet, the color changes for each sheet due to the deviation of dot formation for each color. In addition, the calculation for tilting the image takes time, which causes a significant reduction in productivity. Therefore, skew is determined by the performance of sheet conveyance accuracy.

  As a method for correcting the skew of the sheet, there are the following methods.

  (1) A pair of registration rollers is arranged upstream of the transfer section, and the transfer material that has been conveyed is abutted against the stopped registration roller, and the transfer material is pushed in from the back (loop formation) to perform skew correction. The registration roller is restarted in synchronization with the image, thereby performing skew correction and image alignment in the transport direction.

  (2) Using a retractable shutter instead of the registration roller, the front end of the transferred transfer material is abutted against the closed shutter and the transfer material is pushed in from the back side (loop formation) to perform skew correction. The conveyance is restarted by opening the shutter in synchronization with the image, and skew correction and image alignment in the conveyance direction are performed.

  (2) Correct the skew by transporting the side regulating plate provided in the transport direction while abutting the transfer material with the skew feeding roller, and detect the leading edge of the transfer material by aligning the image in the transport direction. The transfer material speed control is performed (see Patent Document 1).

(3) Means for detecting skew and two independently driveable rollers in the direction perpendicular to the conveyance, and correcting the skew by changing the speed of each drive roller according to the amount of skew (see Patent Document 2) ).
Such a method is used.

  In the method (3), when taking into account the front and back misalignment of images on both sides, the front and back edges of the sheet are switched on the first and second sides by switching back as described above, but the sides are switched. Therefore, there is an advantage that skew can be corrected on the same basis for both the first and second surfaces. In other methods, the skew correction is performed at the leading edge, and the correction standard differs between the first and second surfaces. Therefore, if the parallelism of the leading and trailing edges of the sheet is not obtained, even if the correction capability is high, the front and back shifts. Will occur.

  Here, the method (3) will be described with reference to FIG. This mechanism is a sheet conveying apparatus that conveys a sheet based on a so-called central reference that conveys the sheet by center sorting.

  FIG. 11 shows the upper guide and the upper roller not shown. On the lower guide 102 side of the skew feeding guide portion 100, there are skew feeding rollers 253 to 255 that are supported while being inclined toward the side regulating plate 105. When the sheet is conveyed, the sheet strikes the side regulating plate 105 and skews. It is conveyed while being corrected. Further, since the sheet position in the direction perpendicular to the conveyance direction is determined by the position of the side regulation plate 105, the guide unit 100 can be moved according to the size of the sheet S. A fixed guide 115 is provided on the side opposite to the guide unit 100. The sheet S to be conveyed obliquely is conveyed obliquely until it abuts against the side regulating plate 105 by the obliquely-feeding rollers 253 to 255 while turning, due to the relationship between the center of gravity of the sheet and the conveying direction by the obliquely-feeding rollers 253 to 255. When landing on the restriction plate 105, a landing impact corresponding to the turning amount of the sheet S is applied to the sheet S.

JP-A-11-189355 Japanese Patent Laid-Open No. 5-201587

  As described above, a sheet that is transported obliquely increases the amount of sheet rotation as the skew between the skew feeding direction by the skew feeding roller, the center of gravity of the sheet, and the transport direction increases, and accordingly, when the sheet lands on the side regulating plate. Impact impact also increases. If the impact impact exceeds the allowable buckling level of the seat, it will lead to the occurrence of a collision trace at the end of the seat.

  A sheet conveying unit that conveys a sheet, and a drive unit that drives the sheet conveying unit, guides one end of the sheet in a direction perpendicular to the sheet conveying direction, and moves according to the size of the sheet; A fixed guide for guiding the other end of the sheet, a side regulation plate on which the sheet conveyed obliquely in the guide unit abuts, and a mechanism for swinging the side regulation plate in accordance with the turning direction of the sheet.

  According to the present invention, the following effects can be obtained.

  The left register abutting portion swings according to the turning amount of the paper, and the paper is landed on the abutting portion with the entire paper edge. By controlling the angle of the abutment part so that the abutment part is parallel to the paper edge when touching the abutment part, the landing impact is distributed throughout the paper edge and local stress on the paper Except for, corner breakage of the leading edge of the paper and collision of paper edges are prevented.

Overview of an embodiment of the present invention Registration roller portion of embodiment of the present invention The oblique feeding roller guide portion of the embodiment of the present invention The oblique feeding roller guide portion of the embodiment of the present invention Drive unit for moving oblique guide according to an embodiment of the present invention Side restricting plate swinging portion of an embodiment of the present invention Side restricting plate driving portion A of the embodiment of the present invention Side restricting plate driving portion A of the embodiment of the present invention Side restriction plate driving part A1 of the embodiment of the present invention Side restricting plate driving part B of the embodiment of the present invention Side regulating plate driving part C according to the embodiment of the present invention Cross-sectional view of an image forming apparatus to which the present invention is applied Top view of conventional example Cross section of conventional example

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  The entire apparatus of the present invention will be schematically described with reference to FIG.

  The sheet S, which is a transfer material, is stored so as to be stacked on a lift-up device 11 included in the paper feeding device 10, and is fed by the paper feeding unit 12 in accordance with the image forming timing of the image forming apparatus 90. . Here, the paper feeding means 12 includes a system using frictional separation by a paper feed roller or the like, a system using separation adsorption by air, and the like. In FIG. 10, a paper feeding system using air is taken as an example. The sheet S sent out by the paper feeding unit 12 passes through a transport path of the transport unit 20 and is transported to the registration unit 30. After the skew correction and timing correction are performed in the registration unit 30, they are sent to the secondary transfer unit. The secondary transfer portion is a toner image transfer nip portion to the sheet S formed by the substantially opposite secondary transfer inner roller 43 and secondary transfer outer roller 44, and has a predetermined pressure and static pressure. An unfixed image is transferred to the sheet S by applying an electric load bias.

  A process for forming an image sent to the secondary transfer unit at the same timing as the conveyance process of the sheet S to the secondary transfer unit described above will be described. The image forming unit 90 mainly includes a photoreceptor 91, an exposure device 93, a developing device 92, a primary transfer device 45, a photoreceptor cleaner 95, and the like. The exposure device 93 emits light on the basis of the image information signal sent to the photosensitive member 91 that rotates counterclockwise whose surface is uniformly charged in advance by a charging unit, and appropriately passes through the reflection unit 94 and the like. As a result, a latent image is formed. The toner latent image formed on the photosensitive member 91 in this way is subjected to toner development by the developing device 95 to form a toner image on the photosensitive member. Thereafter, a predetermined pressing force and an electrostatic load bias are applied by the primary transfer device 45, and a toner image is transferred onto the intermediate transfer belt 40. Thereafter, the transfer residual toner slightly remaining on the photosensitive member 91 is collected by the photosensitive member cleaner 95 and is prepared for the next image formation again. In the case of FIG. 16, the image forming unit 90 described above includes four sets of yellow (Y) 90, magenta (M) 96, cyan (C) 97, and black (Bk) 98. Of course, it is not limited to four colors, and the order of colors is not limited to this. Next, the intermediate transfer belt 40 will be described. The intermediate transfer belt 40 is stretched by rollers such as a drive roller 42, a tension roller 41, and a secondary transfer inner roller 43, and is conveyed and driven in the direction of arrow B in the figure. Therefore, the image forming process of each color processed in parallel by the above-described Y, M, C, and Bk image forming apparatuses is performed at the timing of superimposing on the upstream toner image primarily transferred onto the intermediate transfer belt. As a result, a full color toner image is finally formed on the intermediate transfer belt 40 and conveyed to the secondary transfer portion.

  As described above, the full-color toner image is secondarily transferred onto the sheet S in the secondary transfer portion by the conveying process and the image forming process described above. Thereafter, the sheet S is conveyed to the fixing device 50 by the pre-fixing conveyance unit 51. The fixing device 50 melts and fixes the toner on the sheet S by applying a predetermined pressurizing force by a substantially opposed roller or belt and generally a heating effect by a heat source such as a halogen heater. The sheet S having a fixed image obtained in this way is discharged as it is onto the paper discharge tray 61 by the branch conveyance device 60, or is conveyed to the reverse conveyance device 70 when double-sided image formation is required. Route selection is performed.

  Next, a conveying operation when double-sided image formation is required will be described. The sheet S sent to the reverse conveying device 71 is switched back and forwards by a switchback operation, and is conveyed to the duplex conveying device 80. Thereafter, the sheet is joined from the sheet re-feeding path of the transport unit 20 in synchronism with the timing of the sheet S of the subsequent job transported from the sheet feeder 10, and similarly sent to the secondary transfer unit. Since the image forming process is the same as that of the first side, it is omitted.

  Next, a detailed description of the resist unit 30 according to an embodiment of the present invention will be given.

FIG. 1 is a perspective view showing an overall view of a resist portion 30 of the present invention. The registration unit 30 includes a skew feeding roller guide unit 100, a fixed guide unit 110, a skew feeding guide moving drive unit 120, a registration roller unit 130, a registration roller driving unit 140, a registration roller slide unit 150, and a registration roller pressure release unit 160. Consists of.
(Registration roller section 130)
A detailed description will be given with reference to FIG.

  The registration roller unit 130 includes an upper roller 131 and a lower roller 132. The lower roller 132 is rotatably supported by a slide bearing 133 fixed on the frame 200. The upper roller 131 is rotatably supported by a pressure bearing 134 and a plain bearing 133 fixed on the pressure arm 135. The pressing arms 134 and 135 are rotatably fixed to a shaft 200a formed on the frame 200, and both press the upper roller 131 in the direction of the arrow in the drawing by a tension spring 136. Further, a registration roller gear 137 is fixed to the lower roller 132 with screws, and the driving from the registration roller driving unit 140 is transmitted to the lower roller 132. A holder 138 is rotatably supported by a bearing at one end of the lower roller 132. A sensor flag 213 for detecting a home position (hereinafter referred to as HP) position of the registration roller pair (131, 132) in the main scanning direction is attached to the holder 138. Further, the holder 138 is fixed to the timing belt 151 by a stopper 212 and a screw. A roller receiver 210 is fixed to the other end of the lower roller 132. Further, the roller 211 is rotatably supported by the upper roller 131 so as to be engaged therewith. Accordingly, the upper roller 131 and the lower roller 132 can follow the operation of the timing belt 224 and can reciprocate in the main scanning direction in synchronization.

Further, an entrance guide 300a is fixed to the entrance of the registration roller pair (131, 132), an exit guide 301 is fixed to the frame 200 at the exit of the entrance guide 300b, and paper detection sensors 302 and 303 are provided on the guides. ing.
(Registration roller driving unit 140)
The motor 141 fixed to the frame 200 transmits driving to the registration roller gear 137 via the drive gears 142 and 143. Further, the drive gear 143 has a tooth surface length so that the engagement does not drop even when the registration roller gear 137 is reciprocally operated.

The drive gear 142 and the drive gear 143 are rotatably fixed to a fixed shaft via a bearing. The motor 141 rotates in the CCW direction when viewed from the mounting surface side of the motor 141.
(Registration roller slide 150)
The slide motor 159 is fixed to the motor base 152 and is screwed to the motor support plate 153. Drive is transmitted from the slide motor 159 to the holder 138 by a drive train 155 including a timing belt and a pulley.

In this slide mechanism, the registration roller pair (131, 132) moves in the direction A in the figure when the slide motor 159 rotates in the CW direction, and in the direction B in the figure when the slide motor 159 rotates in the CCW direction.
(Registration roller pressure release unit 160)
The registration roller pressure release unit 160 includes a pressure release shaft 161 supported by a bearing positioned on the frame 200 and a release cam 162 fixed to the pressure release shaft 161 with a parallel pin. Deep groove ball bearings 164 are press-fitted into the release cams 162 at positions offset from the respective rotation centers. When the release shaft 161 is rotated once, pressurization and release can be performed once by the action of contact and separation of the deep groove ball bearing 164.

  Further, the drive is transmitted from the registration release motor 165 to the pressure release shaft 161 to rotate the release cam 162.

A sensor flag (not shown) is mounted on the pressure release shaft 161, and the phase of the release shaft 161 is detected by a detection sensor 167 positioned and fixed to a sensor support plate fixed to the frame 200. The rotation is controlled. Further, the phase of the release cam 162 is determined so as to shield the detection sensor 167 when the sensor flag pressurizing operation is performed.
(Slope feed roller guide 100)
This will be described with reference to FIG.

  The skew feeding roller guide portion 100 is further configured by a base portion 101, a lower guide portion 102, an upper guide portion 103, and a hinge portion 104. FIG. 3 is a view showing a state where the upper guide portion 103 is separated. During normal use, the hole 107a of the arm 107 fixed on the upper guide portion 103 is rotatably fitted to the rotation center shaft 106 of the hinge portion 104 fixed on the base portion 101 so as to connect them.

  Rubber feed rollers 253, 254, and 255 are rotatably supported on the lower guide 102, and are driven by a motor (not shown). The skew feeding rollers 253, 254, and 255 are disposed at an angle inclined by θ (deg) with respect to the paper transport direction (C arrow).

  Roller pressurizing units 260, 261, and 262 are fixed on the upper guide 103.

The release rollers 263, 264, and 265 provided in the roller pressure unit 260 are used to switch the pressure rollers 271, 272, and 273 to the obliquely feeding rollers 253, 254, and 255, respectively, between a contact pressure state and a non-contact state. Do. The pressure rollers 271, 272, and 273 are idler rollers that can rotate freely. Further, the release timing of the pressure rollers 271 to 273 is released when the leading edge of the sheet S is sandwiched between the registration rollers, and the sheet trailing edge contacts before the next sheet arrives after passing through the pressure rollers 271 to 273. Operate to the state.
(Declination guide moving drive unit 120)
A detailed description will be given with reference to FIG.

In the oblique feed guide moving drive unit 120, a bearing platform 122 and a bearing platform B 123 are fixed on the base 121, and the base 121 is fixed to the frame 200. The lead screw 124 is rotatably supported by the bearing platform 122 and the bearing platform 123. A nut 125 that slides according to the rotation of the lead screw is provided on the lead screw 124, and a bracket 126 that connects the nut 125 and the oblique feeding guide unit 100 is disposed. A stepping motor, which is a drive motor 127, is connected to the end of the lead screw 124, and the skew feed guide unit is positioned by changing the number of drive pulses according to the size.
(Swing mechanism of side regulating plate)
This will be described with reference to FIG.

The side regulating plate 105 is set as a home position 105-HP at a location parallel to the transfer direction to the transfer unit, and a sensor for detecting the position is provided. A sensor 401 that detects the arrival of a sheet is disposed immediately before the skew feeding roller 253, and the side regulation plate 105 turns to the landing position 105-Landing using the detection signal as a trigger. The landing position is derived from the sheet format read from the user input job information, and the number of drive pulses of the drive motor 505 is changed so as to match the landing position 105-Landing of the side regulating plate 105 suitable for each sheet format. The side regulating plate 105 is turned (swinged) to the landing position 105-Landing. The side regulating plate 105 returns to the HP while the sheet is abutted against the side regulating plate 105 after the landing time predicted for each sheet format from the detection signal of the paper detection sensor 401.
(Side regulating plate drive part Type A)
In the side restricting plate swinging drive unit described with reference to FIG. 7, the bearing base 502 and the bearing base 503 are fixed to the lower portion 101 of the base, and the lead screw 501 is the bearing base 502 and the bearing base 503. Is supported rotatably. A bracket 504 that slides according to the rotation of the lead screw 501 is provided at the lower part of the side regulating plate 105, and the side regulating plate 105 swings according to the amount of rotation of the lead screw 501. A stepping motor, which is a drive motor 505, is connected to the end of the lead screw 501, and the motor drive is transmitted to the lead screw 501 by the worm gear 506, and the lead screw 501 rotates. The drive motor 505 changes the number of drive pulses in accordance with the proper swing angle of the side regulating plate 105 to position the side regulating plate 105. When the side regulating plate 105 swings, the bracket 504 below the side regulating plate 105 rotates between the side regulating plate 105 and the side regulating plate 105 moves by a necessary amount in the paper feeding direction. (Fig. 8)
(Side regulating plate drive unit Type A1)
To explain with reference to FIG. 9, rotation of the bracket 504 under the side regulating plate 105 and movement of the side regulating plate 105 in the paper feeding direction is not required when the side regulating plate 105 is swung. The lead screw 501 may be bent on an arc.

  With the above-described configuration, the effect of mitigating the landing impact of the sheet on the side regulating plate and preventing the occurrence of corner breakage at the front end of the paper and collision flaws at the paper edge can be obtained.

  As described above, the example in which the present invention is applied around the registration rollers has been described. However, the present invention is also applied to a case where a guide having a conveyance roller and a drive unit is moved in a direction perpendicular to the conveyance direction in other conveyance units such as a double-side conveyance unit. It is possible to apply.

(Side regulating plate drive)
A description will be given of another variation of the side restricting plate driving unit with respect to the first embodiment with reference to FIG. 10. The side restricting plate swinging driving unit includes a bearing platform 502 and a bearing platform B 503 at the lower portion 101 of the base unit. The lead screw 501 is rotatably supported by the bearing platform 502 and the bearing platform 503. The lead screw 501 is provided with a bracket 504 that slides according to the rotation of the lead screw 501, and a pin 510 that slides with the cam slit portion of the side regulating plate 501 is provided on the bracket 504. The side restricting plate 105 is provided with the cam slit, and the pin 510 on the bracket 504 moves according to the amount of rotation of the lead screw 501, and the side restricting plate 105 swings according to the amount of movement. A stepping motor, which is a drive motor 505, is connected to the end of the lead screw 501, and the motor drive is transmitted to the lead screw 501 by the worm gear 506, and the lead screw 501 rotates. The drive motor 505 changes the number of drive pulses in accordance with the proper swing angle of the side regulating plate 105 to position the side regulating plate 105.

  With the above-described configuration, the effect of mitigating the landing impact of the sheet on the side regulating plate and preventing the occurrence of corner breakage at the front end of the paper and collision flaws at the paper edge can be obtained.

  As described above, the example in which the present invention is applied around the registration rollers has been described. However, the present invention is also applied to a case where a guide having a conveyance roller and a drive unit is moved in a direction perpendicular to the conveyance direction in other conveyance units such as a double-side conveyance unit. It is possible to apply.

(Side regulating plate drive)
The other variation of the side regulating plate driving unit will be described with reference to FIG. 11 with respect to the first embodiment. The side regulating plate swinging driving unit is fixed to the base lower portion 101 with a bearing platform 502 and a bearing platform 503. The lead screw 501 is rotatably supported by the bearing platform 502 and the bearing platform 503. The lead screw 501 is provided with a bracket 504 that slides according to the rotation of the lead screw 501, and the side regulating plate 105 is always in contact with the bracket by a spring 511. The side regulating plate 105 has a cam shape, and the bracket 504 moves according to the amount of rotation of the lead screw 501 and the side regulating plate 105 swings according to the amount of movement. A stepping motor, which is a drive motor 505, is connected to the end of the lead screw 501, and the motor drive is transmitted to the lead screw 501 by the worm gear 506, and the lead screw 501 rotates. The drive motor 505 changes the number of drive pulses in accordance with the proper swing angle of the side regulating plate 105 to position the side regulating plate 105.

  With the above-described configuration, the effect of mitigating the landing impact of the sheet on the side regulating plate and preventing the occurrence of corner breakage at the front end of the paper and collision flaws at the paper edge can be obtained.

  As described above, the example in which the present invention is applied around the registration rollers has been described. However, the present invention is also applied to a case where a guide having a conveyance roller and a drive unit is moved in a direction perpendicular to the conveyance direction in other conveyance units such as a double-side conveyance unit. It is possible to apply.

DESCRIPTION OF SYMBOLS 90 Image forming part 10 Paper feeder 12 Paper feed means 20 Conveyance unit 30 Registration unit 40 Intermediate transfer belt 50 Pre-fixing conveyance part 51 Fixing device 43 Secondary transfer inner roller 44 Secondary transfer outer roller 70 Reverse conveyance device DESCRIPTION OF SYMBOLS 80 Double-sided conveyance apparatus 100 Inclination feeding guide part 102 Inclination feeding roller lower guide 103 Inclination feeding roller upper guide part 104 Hinge part 105 Side restriction plate 107 Arm 110 Fixed guide part 115 Fixed lower guide 120 Inclination feeding guide moving drive part 124,501 Lead screw 125 Nut 126, 504 Bracket 127 Drive motor 130 Registration roller part 131 Registration upper roller 132 Registration lower roller 134, 135 Pressure arm 137 Registration roller gear 140 Registration roller driving part 150 Registration roller slide part 151 Imming belt 155 Drive train 159 Slide motor 160 Registration roller pressure release unit 161 Pressure release shaft 162 Release cam 165 Registration release motor 167 Detection sensor 200 Frame 213 Sensor flag 253 to 255 Skew feeding roller 260, 261, 262 Rolling pressure unit 263 264, 265 Release motor 271, 272, 273 Pressure roller 300b Under entrance guide 302, 303, 401 Paper detection sensor S Transfer material

Claims (5)

  An apparatus having a sheet conveying means (diagonal feeding roller) that conveys a sheet obliquely and a drive unit that drives the sheet conveying means, and an oblique abutting reference part for guiding one end in a direction perpendicular to the sheet conveying direction. A sheet conveying apparatus having means for detecting and determining the posture of the paper, a mechanism for swinging the abutting portion, and a control means for controlling the swing of the left register abutting portion according to the posture of the paper. ・ The position where the abutting member has the abutting surface parallel to the conveyance direction is HP. ・ Detection means for detecting that the paper has arrived at the abutting member. ・ At a certain angle according to the detected posture of the paper. The sheet conveying apparatus according to claim 1, wherein the swinging control is performed more than the swinging butting member is returned to HP during the butting operation.   The abutting unit stores a paper size, a conveyance direction, and a paper rotation amount and direction corresponding to the paper size, and a paper rotation amount and direction depending on a paper size / conveyance direction input by the user for each job. The sheet conveying apparatus according to claim 1, wherein the position is controlled to a predetermined abutting angle by the abutting portion swinging mechanism. The abutting portion is a component of a guide unit that is movable according to the size of the sheet, and is linked to the paper size and the conveyance direction input by the user for each job. The sheet conveying apparatus according to the description.   5. An image forming apparatus comprising: the sheet conveying apparatus according to claim 1; and an image forming unit that forms an image on a sheet conveyed by the sheet conveying apparatus.

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