JP2010168198A - Paper feeder, and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder capable of constantly and effectively functioning the pre-shuffling by constantly keeping the intended positional relationship of a shuffling guide, a paper feed roll and a separation roll. <P>SOLUTION: The paper feeder includes a paper feed roll 16, a separation roll 17 which is oscillated in the paper feed roll direction and pressed against the paper feed roll 16, and shuffling guides 18 arranged on both proximal sides of a separation nip and oscillated in the paper feed roll direction with the separation roll 17 being pressed against the paper feed roll 16. The shuffling guides 18 are urged by a biasing means 183 different from the separation roll 17 so as to be oscillated following the separation roll 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a paper feeding device having a paper feeding roll, a separation roll (retard roll), and a paper feeding guide for winding paper in front of a separation nip where the separation roll is pressed against the paper feeding roll, and an image using the same. The present invention relates to a forming apparatus.

  FIG. 8 is a diagram showing a configuration example of a paper feed unit in which a separation guide is disposed in front of the separation nip where the separation roll is pressed against the paper feed roll. In the figure, 16 is a paper feed roll, 17 is a separation roll, , A paper feed roll shaft, 171 a separation holder, and 181 a holder with a paper guide.

  In a paper feeding unit of a printer or copying machine, sheets stacked using friction are separated and fed one by one. In this frictional separation, double feeding and non-feeding occur when three or more sheets enter the separation nip. For this purpose, a paper guide 18 for restricting entry in a bundle of paper is provided in front of the separation nip, and the paper is forwarded.

  In the separation nip, a separation roll (retard roll) 17 is brought into pressure contact with the paper feed roll 16, and the whirling guides 18 are disposed on both sides in the axial direction before the separation nip. The position is designed based on the positional relationship between the paper feed roll 16 and the separation roll 17 because it is necessary to limit the entry of the paper into the separation nip. However, in an actual apparatus, the paper feed roll 16 is lifted from the designed position by the separation pressure received from the separation roll 17, so that the front winding may not function effectively.

  As a conventional paper feeder that separates paper from the stacked paper bundle one by one, the paper loaded on the paper feed table that can be moved up and down along the separation edge provided on the paper supply side is rotated. There has been proposed a paper feeding device that sucks and feeds a suction drum (see, for example, Patent Document 1). In this paper feeding device, the top edge of the separating edge is inclined downward toward the paper supply direction, and the top edge is brought close to the suction drum adjacent to the paper supply side of the separating edge toward the separating edge. A whirling guide having a shape inclined on a straight line is provided.

  According to this paper feeding device, the stacked paper P is supplied by the suction drum (3) rotating from the uppermost paper through the paper feeding port (4) between the separation edges while hitting the paper guide. To go. At this time, when a plurality of sheets pass through the sheet feeding port (4) at the same time, the sheets are separated one by one due to the sheet misalignment caused by the inclination of the separating guide (15).

  In addition, assuming that a paper guide is provided in front of the separation nip, the paper entry angle is made sharp by the gap between the paper feed roll and the paper guide, making the paper easier to enter, and the paper guide is made cantilevered. An apparatus that prevents paper jamming by bending the sheet is proposed (for example, see Patent Document 2).

Japanese Patent No. 2654959

JP 2004-269206 A

  FIG. 9 is a diagram for explaining a problem of a conventional paper feeding device having a paper guide. In this conventional example, the paper is moved over the paper guide, so that the front paper is carried out. Therefore, the paper guide is set higher than the surface where the paper contacts the paper feed roll. In the above-described conventional paper feeding apparatus provided with such a whirling guide, even if the whirling guide 18 is in the design positional relationship as shown in FIG. 9A, actually, as shown in FIG. 9B. It will change to a proper positional relationship. This is because the sheet feed roll 16 actually moves by about 0.5 mm, for example, by B shown in FIG. For this reason, as shown in FIG. 9A, the desired paper sheet P cannot be obtained by setting the paper guide 18 higher than the surface where the paper P contacts the paper feed roll 16 by A.

  Such a problem also occurs in the conventional paper feeder proposed in Patent Document 1. In the paper feeder disclosed in Patent Document 1, it is necessary for the paper guide to be close to the suction drum with a gap of about one sheet of paper, for example. Therefore, it is necessary to arrange the paper feed roll and the winding guide with high accuracy. However, in an actual apparatus, the paper feed roll is lifted by, for example, about 0.5 mm from the design target position due to the separation pressure received from the separation roll. For this reason, there is a problem that the gap between the paper feed roll and the paper guide becomes larger than expected, and the front paper using the paper guide does not function effectively.

  Also, in the conventional paper feeding device proposed in Patent Document 2, since the separating guide is provided integrally with the base of the paper feeding device, if the paper feeding roll is lifted by the separation pressure, The gap cannot be maintained.

  An object of the present invention is to keep the positional relationship among the winding guide, the paper feed roll, and the separation roll as intended, and to make the front winding function effectively.

A sheet feeding device and an image forming apparatus using the same according to the present invention include a sheet feeding roll, a separation roll that swings in the direction of the sheet feeding roll and presses against the sheet feeding roll, and swings in the direction of the sheet feeding roll. A separation guide disposed on both sides of the front side of the separation nip where the separation roll comes into pressure contact with the sheet feeding roll, and the separation guide is biased differently from the separation roll so as to swing following the separation roll. It is biased by means.

  The separation guide has an abutting portion between the separation roll and an abutting portion in which a range swinging in the direction of the paper feed roll is limited by the separation roll. The biasing pressure of the biasing means is larger than the biasing pressure of the whirling guide.

  In addition, a plurality of urging means for the separating roll are arranged in the axial direction, and the urging means for the separating guide are arranged in the axial direction between the urging means for the separating roll, and the separating roll and the separating roll The guide urging means is arranged in a direction perpendicular to the axial direction of the separating roll, and either one of the separating roll and the urging guide urging means is arranged on the back side with respect to the front sheet feeding side. The other is arranged on the lower surface side, and the urging means of the whirling guide is arranged between the holder of the separating roll.

  The swing fulcrum of the separation roll and the separation guide is arranged on a straight line parallel to the axial direction of the separation roll, and the holder of the separation roll has an auxiliary separation portion. .

According to the present invention, the separation guide and the separation holder are separated from each other, and the separation guide is provided so as to follow the position of the separation roller. Therefore, the separation guide, the paper feed roll, and the separation roll are always in the intended positional relationship. Kept. Therefore, it is always possible to make the front-end function effectively.

It is a figure explaining embodiment of the paper feeder concerning this invention. It is a figure explaining operation | movement of embodiment of the paper feeder which concerns on this invention. It is a figure which shows the example of the paper feeder which has arrange | positioned three springs to the axial direction as an Example of this invention. It is a figure which shows the example of the paper feeder which has arrange | positioned two springs in the direction orthogonal to an axial direction as an Example of this invention. FIG. 4 is a diagram illustrating an example of a paper feeding device in which one spring is disposed on the back side and one on the lower surface side as an embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a sheet feeding device in which one spring is disposed on the back side and one is disposed between a separation holder on the lower surface side and a holder with a winding guide as an embodiment of the present invention. 1 is a diagram illustrating an embodiment of an image forming apparatus using a paper feeding device according to the present invention. FIG. 6 is a diagram illustrating a configuration example of a sheet feeding unit in which a separation guide is disposed in front of a separation nip where a separation roll is pressed against a sheet feeding roll. It is a figure explaining the subject of the conventional paper feeder provided with the paper guide.

  Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are diagrams illustrating an embodiment of a paper feeding device according to the present invention, in which FIG. 1A is a front view, FIG. 1B is a cross-sectional view taken along line AA, and FIG. It is a figure explaining operation | movement of. In the figure, 16 is a paper feed roll, 17 is a separation roll, 18 is a separating guide, 30 is a housing, 161 is a paper feed roll shaft, 170 is a torque limiter, 171 is a separation holder, 172 and 182 are swing support points, 173, Reference numeral 183 denotes a spring, 181 denotes a holder with a winding guide, and 201 denotes a lift plate.

  In the embodiment of the paper feeding device according to the present invention, as shown in the front view of FIG. 1A, a paper feeding roll 16 and a separation roll (retarding roll) 17 that is in pressure contact with the paper feeding roll 16 are arranged at the center. The separating guides 18 are arranged on both sides of the separation roll 17 on the sheet feeding side before the separation nip where the separation roll 17 is in pressure contact with the sheet feeding roll 16. The paper feed roll 16 is rotated by a paper feed roll shaft 161 to perform a paper feed operation.

  The separation roll 17 is attached to a fixed shaft fixed to the separation holder 171 so as not to rotate so as to rotate integrally with the torque limiter 170. The separation holder 171 is pivotally supported around a swing fulcrum (rotation fulcrum) 172 so as to be rotatable (oscillate), and the outer periphery of the sheet feeding roll 16 is separated from the separation roll 17 by the bias of a spring 173 as a biasing means. The surface is held on the housing 30 side in a pressure contact state.

  The torque limiter 170 is used when the outer peripheral surfaces formed by the friction members of the paper feed roll 16 and the separation roll 17 are in direct pressure contact with each other, or when the outer peripheral surfaces are in direct pressure contact with the paper dragged by the paper feed roll 16. The separation roll 17 is set so as to be driven to rotate by the friction force. On the other hand, the torque limiter 170 is set to stop the press-contacted paper by stopping by the frictional force between the papers dragged by the paper supply roll 16.

  The whirling guide 18 is formed in a part of the whirling guide holder 181. Like the separation holder 171, the holder 181 with the whirling guide is pivotally supported so as to be rotatable (swingable) about the swinging fulcrum 182. Then, a spring 183 different from the spring 173 is disposed on the back side with respect to the front sheet feeding side and is urged to swing following the separation roll 17.

  Here, the biasing pressure of the spring 173 is larger than the biasing pressure of the spring 183. Further, the separation guide 18 has a contact portion between the separation guide 181 and the separation holder 171 in which the range of swinging in the direction of the paper feed roll is limited by the separation roll 17. The swing fulcrums 172 and 182 are arranged on a straight line parallel to the axial direction of the separation roll 17.

  According to the sheet feeding device of the present embodiment configured as described above, the holder 181 with the separation guide is normally pressed against the separation holder 171 as shown in FIG. For this reason, the force at the leading edge of the paper P loaded on the lift plate 201 works only on the winding guide 18, and the force that opens the separation nip where the separation roll 17 presses against the paper feed roll 16 does not work. On the other hand, when a force larger than usual is applied to the guide 18 due to the sudden entry of the sheet bundle, only the holder 181 with the guide is pushed down as shown in FIG. However, since the force at the front end of the paper P does not act on the separation holder 171, the separation nip is not opened.

[Example 1]
3A and 3B are diagrams showing an example of a paper feeding device in which three springs are arranged in the axial direction as an embodiment of the present invention. FIG. 3A is a front view, FIG. 3B is a right side view, and FIG. (D) is AA sectional drawing, (E) is BB sectional drawing.

  In this embodiment, as shown in the rear view of FIG. 3C, a spring 173 for urging the separation holder 171 is arranged at the center, and springs 183 are arranged on both sides of the spring 173 in the axial direction. The holder 181 with guide is urged.

  Therefore, the holder 181 with a whirling guide is provided with a notch at the position where the spring 173 that biases the separation holder 171 is disposed. Conversely, the spring 183 may be disposed at the center, and the spring 173 may be disposed on both sides of the spring 183 in the axial direction. In this way, the pair of springs 183 urges the holder 181 with the whirling guide, and a part of the inner wall of the holder 181 with the whirling guide and a part of the outer wall of the separation holder 171 are brought into contact with each other as a contact part. Thus, the position of the holder 181 with the whirling guide, that is, the whirling guide 18 is determined.

[Example 2]
4A and 4B are views showing an example of a paper feeding device in which two springs are arranged in a direction orthogonal to the axial direction as an embodiment of the present invention, where FIG. 4A is a front view, FIG. 4B is a right side view, and FIG. ) Is a rear view, (D) is an AA cross-sectional view, and (E) is a BB cross-sectional view.

  In this embodiment, as shown in the right side view of FIG. 4B, the rear view of FIG. 4C, and the cross-sectional views of FIG. 4D and FIG. The spring 183 is arranged below the spring 173 and in a direction perpendicular to the axial direction, and the holder 181 with a rolling guide is urged.

  Therefore, the holder 181 with a whirling guide is provided with a notch at the position where the spring 173 that biases the separation holder 171 is disposed. In this manner, the spring 183 biases the holder 181 with a guide while making a part of the inner wall of the holder 181 with the guide and a part of the outer wall of the separation holder 171 contact as a contact part. The guide holder 181, that is, the position of the rolling guide 18 is determined.

Example 3
FIGS. 5A and 5B are diagrams showing an example of a sheet feeding device in which one spring is arranged on the back side and one on the bottom side as an embodiment of the present invention, FIG. 5A is a front view, and FIG. 5B is a right side view. (C) is a rear view, (D) is an AA cross-sectional view, and (E) is a BB cross-sectional view.

  In this embodiment, as shown in the rear view of FIG. 5C, a spring 173 for urging the separation holder 171 is arranged at the center, and a guide is provided in the direction perpendicular to the axial direction with respect to the position of the spring 173. A spring 183 is arranged on the lower surface side of the holder 181 to bias the holder 181 with a rolling guide. Here, the spring 173 may be disposed on the lower surface side, and the spring 183 may be disposed on the rear surface side.

  Therefore, the holder 181 with a whirling guide is provided with a notch at the position where the spring 173 that biases the separation holder 171 is disposed. In this manner, the spring 183 biases the holder 181 with a guide while making a part of the inner wall of the holder 181 with the guide and a part of the outer wall of the separation holder 171 contact as a contact part. The guide holder 181, that is, the position of the rolling guide 18 is determined.

Example 4
FIG. 6 is a view showing an example of a sheet feeding device in which one spring is disposed on the back side and one is disposed between the separation holder on the lower surface side and the holder with a winding guide as an embodiment of the present invention. Is a front view, (B) is a right side view, (C) is a rear view, (D) is an AA sectional view, and (E) is a BB sectional view.

  In this embodiment, as shown in the rear view of FIG. 6C, a spring 173 for urging the separation holder 171 is arranged in the center, and the spring 173 is positioned on the lower surface side of the holder 181 with a guide. A spring 183 is disposed between the separation holder 171 and the spring 183.

  The holder 181 with a whirl guide abuts a part of its inner wall and a part of the outer wall of the separation holder 171 as a contact portion, and biases the holder 181 with a whirl guide in a fixed positional relationship with the separation holder 171.

  In this embodiment, the spring 183 is attached between the separation holder 171 and the holder 181 with a winding guide, so that the spring 183 has a fixed guide with a fixed position relative to the separation holder 171 that rotates and swings around the swing fulcrum 172. The holder 181 also rotates and swings. Then, the spring 183 acts so that only the holder 181 with the winding guide is pushed down due to the presence of the spring 183 when a force larger than usual is applied to the winding guide 18 due to the sudden entry of the sheet bundle. .

  As described above, there is provided a paper feeding device having a paper feeding roll, a separation roll (retard roll), and a separation guide for winding paper before the separation nip where the separation roll is pressed against the paper feeding roll. In the apparatus, the rolling guide is disposed at a fixed position and does not follow the position of the separation roll. Therefore, in the present embodiment, the holder with a separating guide and the separation holder are separately structured and spring-biased so that the position of the separation guide that has been conventionally fixed follows the separation roll. As a result, even when the paper feed roll is lifted, the positional relationship among the winding guide, the paper feed roll, and the separation roll is always maintained as intended. Further, a separating portion may be provided on the separation holder as an auxiliary to the separating guide.

  FIG. 7 is a diagram for explaining an embodiment of an image forming apparatus using a paper feeding device according to the present invention. In the figure, 1 is a rotary developing device, 2 is a developing device, 3 is a photosensitive member, and 4 is an intermediate transfer member. 5 is an exposure device, 6 is a process unit, 7 is a primary transfer device, 8 is a secondary transfer device, 9 and 10 are paper feed devices, 11 is a registration roll, 12 is a paper transport unit, 13 is a fixing unit, and 14 is A paper discharge tray, 15 is a door, 16 is a paper feed roll, 17 is a separation roll, and 20 is a bottom plate.

As shown in FIG. 7, the image forming apparatus using the paper feeding device of the present embodiment includes a paper discharge tray 14 formed at the upper part of the housing, and a door body 15 that is attached to the front surface of the housing so as to be opened and closed. . In the housing, a rotary developing device 1 having a plurality of developing devices 2 mounted thereon, a photosensitive member 3 on which a latent image is formed and developed to form a toner image, and an exposure device that exposes the photosensitive member 3 to form a latent image. 5. An intermediate transfer body 4 composed of an endless belt to which a toner image is transferred, and a process unit 6 for controlling the formation of a latent image by the exposure device 5 are arranged.

  Further, a primary transfer device 7 for primary transfer of the toner image on the photoreceptor 3 to the intermediate transfer member 4, a secondary transfer device 8 for secondary transfer of the toner image of the intermediate transfer member 4 to the paper, and a paper supply for housing the paper. There are disposed paper devices 9 and 10, a fixing unit 13 for fixing a toner image on the paper, a control unit for controlling each drive motor and bias.

  A paper transport unit 12 that transports paper from the paper feeders 9 and 10 to the fixing unit 13 through the secondary transfer device 8 is disposed in the door body 15. Each unit is configured to be detachable from the main body, and can be removed and repaired or replaced integrally during maintenance or the like.

  The photoreceptor 3 as an image carrier has a thin cylindrical conductive substrate and a photosensitive layer formed on the surface thereof. On the outer periphery of the photoconductor 3, a charging device (not shown) for uniformly charging the photoconductor 3 along the rotation direction, an exposure device 5 for forming a latent image on the photoconductor 3, a latent image A rotary developing device 1 for developing an image, an intermediate transfer member 4 to which a toner image on the photosensitive member 3 is transferred, and a primary transfer device 7 for primary transfer of the toner image to the intermediate transfer member 4 after primary transfer A cleaner (not shown) for cleaning the surface of the photosensitive member 3 is disposed.

  The latent image formed by the exposure device 5 on the photosensitive member 3 is developed by the rotary developing device 1 to form a toner image, and the formed toner image is transferred onto the intermediate transfer member 4 by the primary transfer device 7. Then, the image is further transferred onto the paper by the secondary transfer device 8.

  In full-color image formation by the image forming apparatus having the above-described configuration, when an image formation signal is input from the process unit 6 to the exposure device 5, the photoconductor 3 and the rotary developing device are controlled according to the drive motor and bias control by the control unit. 1. The intermediate transfer member 4 is driven to rotate. The outer peripheral surface of the photoreceptor 3 is uniformly charged by a charging device.

  Since the rotary developing device 1 forms a toner image of the first color, for example, yellow Y, the developing device 2 for yellow Y causes the rotation center of the rotary developing device 1 and the rotation center of the photoreceptor 3 to be changed by a developing color switching operation. Rotate and move beyond the straight line connecting Then, on the downstream side in the direction of rotational movement of the rotary developing device 1, the developing rolls or rollers disposed at both ends of the developing roll (hereinafter the same) contact the photoreceptor 3 and stop.

  At the same time as the developing roll of the developing device 2 is driven to rotate, the surface of the photosensitive member 3 is first subjected to selective exposure according to the image information of the first color and yellow Y by the exposure device 5, so that the surface of the photosensitive member 3 is exposed. A yellow Y latent image is formed. The yellow Y latent image is developed by the developing device 2 to form a toner image on the photoreceptor 3.

  As soon as the rear end of the yellow Y latent image is developed by the developing unit 2 and development is completed, the rotary developing device 1 immediately after that, that is, before the rear end of the toner image reaches the primary transfer device 7, The developing color switching operation for forming a color, for example, a black K toner image is started.

  By this developing color switching operation, the developing roll of the developing device 2 for black K rotates and moves further beyond the straight line connecting the rotation center of the rotary developing device 1 and the rotation center of the photosensitive member 3, and the rotary developing device 1. And abut against the photosensitive member 3 on the downstream side in the rotational movement direction.

  During this time, a primary transfer voltage having a polarity opposite to the toner charging polarity is applied to the primary transfer device 7, and the toner image formed on the photoreceptor 3 is transferred onto the intermediate transfer member 4 by the primary transfer device 7. Transcribed. The secondary transfer device 8 is separated from the intermediate transfer member 4.

  When the developing color switching operation for the second color is completed and the developing roll of the developing device 2 for black K comes into contact with the photosensitive member 3 and stops, the second color, black K is applied to the surface of the photosensitive member 3 by the exposure device 5. The black K latent image is formed on the photoreceptor 3 by selective exposure according to the image information. Such a series of processing is repeatedly executed corresponding to the second color, the third color, and the fourth color of the image forming signal, so that yellow Y, black K, cyan corresponding to the contents of each image forming signal. Four color toner images composed of C and magenta M are sequentially superimposed and transferred from the photosensitive member 3 onto the intermediate transfer member 4 to form a full-color image.

  Then, at the timing when the full color image reaches the secondary transfer device 8, the paper of the paper feeding devices 9, 10 is conveyed from the conveyance path to the secondary transfer device 8 through the paper feeding roll 16, the intermediate conveyance roll, and the registration roll 11. The secondary transfer device 8 is pressed against the intermediate transfer body 4 and a secondary transfer voltage is applied, and the four color full-color toner images on the intermediate transfer body 4 are transferred onto the paper by the secondary transfer device 8.

  When the sheet on which the full-color toner image has been transferred in this manner is conveyed to the fixing unit 13 by the paper conveying unit 12, the full-color toner image on the sheet is heated and pressed by the fixing unit 13 to be fixed. The paper is discharged.

  DESCRIPTION OF SYMBOLS 1 ... Rotary developing device, 2 ... Developing device, 3 ... Photoconductor, 4 ... Intermediate transfer body, 5 ... Exposure device, 6 ... Process unit, 7 ... Primary transfer device, 8 ... Secondary transfer device, 9, 10 ... Paper feeding device, 11 ... registration roll, 12 ... paper transport unit, 13 ... fixing unit, 14 ... discharge tray, 15 ... door, 16 ... paper feed roll, 17 ... separation roll, 18 ... waki guide, 20 ... bottom plate, DESCRIPTION OF SYMBOLS 30 ... Housing, 161 ... Paper feed roll axis, 170 ... Torque limiter, 171 ... Separation holder, 172, 182 ... Swing fulcrum, 173, 183 ... Spring, 181 ... Holder with winding guide, 201 ... Lift plate

Claims (10)

A feed roll;
A separation roll that swings in the direction of the paper feed roll and presses against the paper feed roll;
A separation guide disposed on both sides of the separation nip that swings in the direction of the sheet feed roll and presses the separation roll against the sheet feed roll, and the separation guide swings following the separation roll. Thus, the sheet feeding device is biased by a biasing means different from the separation roll. 2. The feeding according to claim 1, wherein the separation guide has an abutting portion between the separation roll and a range of swinging in the direction of the sheet feeding roll, which is limited by the separation roll. Paper device. 3. The sheet feeding device according to claim 1, wherein an urging pressure of the urging unit of the separating roll is larger than an urging pressure of the whirling guide. The urging means of the separation roll is arranged in a plurality in the axial direction, and the urging means of the separating guide is arranged in the axial direction between the urging means of the separation roll. The sheet feeding device according to any one of 1 to 3. 4. The sheet feeding device according to claim 1, wherein biasing means of the separation roll and the separation guide are arranged in a direction perpendicular to the axial direction of the separation roll. 5. One of the separating roll and the biasing means of the separating guide is disposed on the back side with respect to the front sheet feeding side, and the other is disposed on the lower surface side. The sheet feeder according to any one of the above. The paper feeding device according to claim 6, wherein the urging means of the whirling guide is disposed between the separation roll and the holder. The sheet feeding device according to any one of claims 1 to 7, wherein swinging fulcrums of the separating roll and the separating guide are arranged on a straight line parallel to an axial direction of the separating roll. The sheet feeding device according to claim 1, wherein the separation roll holder includes an auxiliary separating unit. An image forming apparatus using the sheet feeding device according to claim 1.

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