JP2010168200A - Paper feeding device and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of non-feed even when the projection of a waved paper sheet is at the position of an auxiliary roller. <P>SOLUTION: The paper feeding device includes a crescent paper feed roller 16, a pair of auxiliary rollers 18 arranged on both sides of the paper feeding roller 16, a one-way clutch 181 arranged between a drive shaft 161 of the paper feeding roller and each of the auxiliary rollers 18, and a separation member 17 coming into pressure contact with the paper feeding roller 16 or the auxiliary rollers 18. The one-way clutch 181 connects the auxiliary rollers 18 to the drive shaft 161 to integrally rotate the auxiliary rollers 18 in the rotational direction of the drive shaft 161 by a paper feeding operation, and disconnects the auxiliary rollers 18 from the drive shaft 161 to rotate in a driven manner the auxiliary rollers 18 in accordance with the paper sheet conveyance in a paper sheet conveyance direction. Accordingly, the occurrence of non-feed is prevented, and the load to a conveyance roller and the influence to paper sheet traveling accuracy are reduced even when the projection of the waved paper sheet is at the position of the auxiliary roller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a paper feeding device using a half-moon shaped paper feeding roll, an auxiliary roll, and a separation member that presses them, and a paper feeding device that improves the paper feeding performance of paper that has been greatly waved due to moisture absorption, and image formation using the same. Relates to the device.

  4 is a diagram for explaining a conventional paper feeding device using a half-moon-shaped paper feeding roll, FIG. 5 is a diagram for explaining a paper feeding operation of the paper feeding device using a half-moon shaped paper feeding roll, and FIG. 6 is a half-moon. FIG. 7 is a diagram for explaining the difference between the adjustment of the gap between the sheet-shaped paper feed roll and the paper entry guide and the paper conveyance failure, FIG. 7 is a diagram for explaining the difference between the retard roll and the separation pad, and FIG. It is a figure explaining the malfunction of the paper conveyance by the formed paper. In the figure, 16 is a half-moon-shaped paper feed roll, 17 is a retard roll, 17 'is a separation pad, 18 is an auxiliary roll, 20 is a bottom plate, 21 is a paper entry guide, 161 is a drive shaft, 171 is a rotation fulcrum, 171 'Denotes a spring biasing mechanism, and P denotes a sheet.

  As a sheet feeding device, there is a conventional one constituted by a half-moon shaped sheet feeding roll 16 as shown in FIG. 4, an auxiliary roll 18 having a smaller diameter than the sheet feeding roll, and a retard roll 17 which is a separation member pressed against it. .

  The auxiliary roll 18 is generally smaller in diameter than the half-moon-shaped paper feed roll 16 and is generally disposed on both sides of the paper feed roll 16 around the same drive shaft 161 as the paper feed roll 16. . As shown in FIG. 5, the retard roll 17 swings around a rotation fulcrum 171 and is urged in the direction of the half-moon-shaped paper feed roll 16 by a spring member, and is pressed against the paper feed roll 16 or the auxiliary roll 18. To do.

  As shown in FIG. 5A, the retard roll 17 is further moved by being biased by a spring member from the position of the outer peripheral portion of the paper feed roll 16 when the half-moon notch of the paper feed roll 16 is at the opposing position. Then, it is pressed against the auxiliary roll 18. Accordingly, at this time, the half-moon-shaped paper feed roll 16 is not in contact with the paper P.

  Then, when the paper feeding operation is started and the drive shaft 161 is rotated and the outer peripheral portion of the paper feeding roll 16 is rotated to the position opposite to the retard roll 17 as shown in FIG. Is started to be pressed down by the paper feed roll 16. In this way, the retard roll 17 is oscillated by the spring member about the rotation fulcrum 171 in the direction in contact with the half-moon-shaped paper feed roll 16, and moves up and down by the paper feed operation.

  In the paper feeding unit, the paper G stacked on the bottom plate 20 is separated and fed one by one by adjusting the gap G between the paper feed roll 16 and the paper entry guide 21 shown in FIG. If the gap G is too narrow, the leading edge of the paper P collides with the paper entry guide 21 as shown in FIG. 6A, and conversely if the gap G is too wide, the paper as shown in FIG. 6B. The leading edge of P collides with the surface of the retard roll 17 and the paper conveyance stops. Therefore, the gap G between the paper entry guide 21 and the half-moon-shaped paper feed roll 16 is adjusted appropriately.

  Management of the gap G between the paper entry guide 21 and the half-moon-shaped paper feed roll 16 is particularly difficult when the retard roll 17 is used as the separating member as shown in FIG. However, when the separation pad 17 ′ is used as the separation member as shown in FIG. 7B, the front of the paper P smoothly enters the paper P without a problem of colliding with the surface like the retard roll 17. Therefore, the paper P can enter and a paper feed error is unlikely to occur.

  Regardless of the configuration, in the paper feeder provided with the half-moon-shaped paper feed roll 16, by providing the auxiliary roll 18 that idles on both sides, the half-moon-shaped paper feed roll 16 can be rotated only once. The feeding and separation of the paper P and the transport of the paper P to the transport unit at the transport destination are completed. Therefore, the driving device and the control are simple and are adopted in many paper feeding devices.

  In such a paper feeding device provided with a half-moon shaped paper feeding roll, two auxiliary rolls are generally arranged on both sides of one paper feeding roll, and they are set as a pair of roll sets. As an example, one or a plurality of roll sets are used. However, as a problem of a paper feeding device provided with one half-moon shaped paper feeding roll and two auxiliary rolls, the paper feeding performance is worse than that of other paper feeding devices in the case of paper having a large ripple due to moisture absorption. Is mentioned.

  Such a problem is caused by wave absorption due to moisture absorption as shown in FIG. 8 (A) in a state before the start of paper feeding where the half-moon shaped paper feeding roll 16 and the paper P are not in contact as shown in FIG. 5 (A). This occurs when the peak position of the convex of the paper P that is formed in the above overlaps with the position of the auxiliary roll 18. In this case, as shown in FIG. 8B, even when the half-moon-shaped sheet feed roll 16 rotates, the half-moon-shaped sheet feed roll 16 cannot contact the sheet P, or the half-moon-shaped sheet feed roll 16 is not touched. The paper pressing force is weakened, and non-feed (feed error) and oblique feed are likely to occur.

  Therefore, by arranging the auxiliary rolls (22a, 22b, 22c) in which a plurality of half-moon-shaped paper feed rolls (5a, 5b, 5c, 5d) run idle, at the end of the half-moon shaped paper feed roll There has been proposed a configuration that prevents contact between the auxiliary roll and the convex portion of the corrugated paper and prevents the occurrence of non-feeding and oblique feeding (for example, see Patent Document 1).

JP 2006-160443 A

  However, the conventional apparatus proposed in Patent Document 1 is effective in improving the paper feeding performance of corrugated paper, but since there are a plurality of half-moon shaped paper feeding rolls, the contact friction with the separating member also increases. Further, a sheet fed by only rotating the half-moon-shaped sheet feeding roll once is transported by a transport roll ahead, but the load on the transport roll also increases. Therefore, adverse effects such as affecting the paper conveyance accuracy and increasing the size of the drive motor occur. In addition, in order to prevent non-feeding and oblique feeding, the contact state between the paper feed roll and the separating member must be made uniform, which causes a problem that the apparatus becomes complicated or large.

  It is an object of the present invention to prevent the occurrence of non-feeding even when the convex portion of corrugated paper is at the position of the auxiliary roll, reduce the load on the transport roll, and reduce the influence on the paper running accuracy. .

  A sheet feeding device and an image forming apparatus using the sheet feeding device according to the present invention include a half-moon shaped sheet feeding roll, a pair of auxiliary rolls disposed on both sides of the sheet feeding roll, and a drive shaft of the sheet feeding roll. A one-way clutch disposed between each of the auxiliary rolls, and a separation member that presses against the paper feed roll or the auxiliary roll, and the one-way clutch rotates in a direction in which the drive shaft rotates by a paper feeding operation. The auxiliary roll is connected to the drive shaft so that the auxiliary roll rotates integrally with the drive shaft, and the auxiliary roll is rotated with the drive shaft so that the auxiliary roll is driven to rotate as the paper is conveyed in the direction in which the paper is conveyed. It is characterized by releasing from the connection.

  Further, the outer peripheral surface of the auxiliary roll is made of the same material as the outer peripheral surface of the paper feed roll, and the separation member is a separation roll or a separation pad. The outer diameter of the roll is smaller than or equal to the outer diameter of the paper feed roll.

  According to the present invention, since the auxiliary roll and the drive shaft are connected via the one-way clutch, and the auxiliary roll is integrally rotated with the drive shaft by the paper feeding operation, the convex portion of the corrugated paper is at the position of the auxiliary roll. Also, the paper is conveyed by the auxiliary roll. Therefore, no paper non-feed does not occur. Further, after the drive shaft is stopped, the auxiliary roll is in a state where it can idle, and is rotated following the conveyance of the sheet by the conveyance roll downstream of the paper supply roll. Therefore, the load on the transport roll is reduced and the influence on the paper running accuracy is reduced. In addition, by using the same material for the outer peripheral surface of the auxiliary roll as that of the outer peripheral surface of the paper feed roll, the wear rate is the same, and the outer diameter difference between the auxiliary roll and the paper feed roll can be maintained within the lifetime. it can.

It is a figure explaining embodiment of the paper feeder concerning this invention. 1 is a diagram illustrating an embodiment of an image forming apparatus using a sheet feeding device according to the present invention. FIG. 2 is an external view of the image forming apparatus and an enlarged view of a paper feeding unit. It is a figure explaining the paper feeding apparatus using the conventional half-moon shaped paper feeding roll. FIG. 6 is a diagram illustrating a sheet feeding operation of a sheet feeding device using a half-moon shaped sheet feeding roll. FIG. 6 is a diagram for explaining a problem of adjustment of a gap between a half-moon-shaped sheet feeding roll and a sheet entry guide and sheet conveyance. It is a figure where the separation member explains the difference between a retard roll and a separation pad. It is a figure explaining the malfunction of the paper conveyance by the paper by which the waviness became large by moisture absorption.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an embodiment of a paper feeding device according to the present invention, FIG. 2 is a diagram illustrating an embodiment of an image forming device using the paper feeding device according to the present invention, and FIG. 3 is an external view of the image forming device. 1 is a rotary developing device, 2 is a developing device, 3 is a photosensitive member, 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, 10 is a paper feeder, 11 is a registration roll, 12 is a paper transport unit, 13 is a fixing unit, 14 is a paper discharge tray, 15 is a door, 16 is a paper feed roll, and 17 is a retard roll. , 18 is an auxiliary roll, 20 is a bottom plate, 161 is a drive shaft, and 181 is a one-way clutch.

  In FIG. 1 (A), the paper feed roll 16 has a half-moon notch, and its outer peripheral surface is made of a friction member such as rubber or synthetic resin having a large friction coefficient. The drive shaft 161 is rotationally driven in the direction of transporting paper by a paper feed operation, and the paper feed roll 16 is attached and fixed to the drive shaft 161. The retard roll 17 has a built-in torque limiter, and when a plurality of sheets enter, the retard roll 17 prevents the entry of the sheet on the retard roll 17 side by the torque limiter built in the retard roll 17 so that one sheet is frictionally separated and sent out. Is.

  The auxiliary rolls 18 are, for example, a pair of rolls whose outer diameter is about 0.5 mm smaller than the paper feed roll 16, and are attached to the drive shaft 161 via the one-way clutch 181. As with the paper feed roll 16, the pair of auxiliary rolls 18 are configured by friction members such as rubber and synthetic resin having a large friction coefficient on the outer peripheral surface, and are disposed on both sides of the paper feed roll 16.

  The one-way clutch 181 connects the auxiliary roll 18 to the drive shaft 161 with respect to the rotation direction of the drive shaft 161 that rotationally drives the paper feed roll 16 by a paper feeding operation. Therefore, the auxiliary roll 18 rotates integrally with the paper feed roll 16 by the paper feed operation. The one-way clutch 181 releases the connection of the auxiliary roll 18 from the drive shaft 161 with respect to the rotation direction opposite to the direction in which the sheet is conveyed. Therefore, at this time, the auxiliary roll 18 is in a free rotating state with respect to the drive shaft 161.

  By disposing the one-way clutch 181 between the auxiliary roll 18 and the drive shaft 161, the auxiliary roll 18 is driven by one rotation by a paper feeding operation and then is a conveyance roll (not shown) at the conveyance destination of the separation nip. As the paper is transported, the paper is idled. In FIG. 1A, when the separation direction of the separation nip where the retard roll 17 is in pressure contact with the sheet feeding roll 16 is the conveyance direction of the left back side from the illustrated right front side, the conveyance roll is a conveyance destination in the illustrated left back direction. (Not shown).

  The torque limiter built in the retard roll 17 is in direct pressure contact with the paper dragged by the paper feed roll 16 when the outer peripheral surfaces formed by the friction members of the paper feed roll 16 and the retard roll 17 are in direct pressure contact with each other. In this case, the retard roll 17 is set to rotate following the paper feed roll 16 by the mutual frictional 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 retard roll 17 is driven to rotate as the sheet is conveyed when one sheet enters between the sheet feed roll 16 and the retard roll 17 (separation nip). However, when a plurality of sheets enter the separation nip, the entry of the sheet on the retard roll 17 side is prevented by the torque limiter built in the retard roll 17. Here, the friction coefficient between the paper feed roll 16 and the paper, the friction coefficient between the retard roll 17 and the paper, and the difference in the friction coefficient between the paper and the paper are used. As described above, the configuration in which the retard roll 17 including the torque limiter is pressed against the paper feed roll 16 in the separation nip allows one paper to be frictionally separated and sent out, which causes non-feed (feed error) and oblique feed. Can be prevented, and even double feeding can be prevented.

  According to the present embodiment having the above configuration, even when the undulation of the paper P increases due to moisture absorption and the convex portion of the undulating paper P is at the position of the auxiliary roll 18, the occurrence of non-feed can be prevented. That is, even if the convex portion (peak position) of the paper P, which has become wavy due to moisture absorption, overlaps the position of the auxiliary roll 18 as shown in FIG. 1B, the drive shaft 161 and the auxiliary roll 18 are fed by the paper feeding operation. And the leading edge of the paper moves as the auxiliary roll 18 rotates, so that it is possible to prevent non-feeding.

  In addition, since the auxiliary roll 18 is disposed on the drive shaft 161 via the one-way clutch 191, the auxiliary roll 18 after the drive shaft 161 is stopped can be idled and transported in the paper transport direction. As the paper is conveyed by the roll, it is driven to rotate (idling). Therefore, the load on the transport roll is reduced, and the influence on the paper running accuracy is reduced. Further, since the wear on the surface of the auxiliary roll is reduced, there is little change in the outer diameter, the positional relationship with the separation roller 17 can be maintained in a durable manner, and good paper feeding and separation performance can be obtained.

Thus, at the start of paper feeding, the auxiliary roll 18 also rotates integrally with the paper feeding roll 16 along with the driving rotation of the drive shaft 161. However, the outer diameter of the auxiliary roll 18 is the same as that of the conventional apparatus. Even if it is smaller than the diameter by about 0.5 mm, it may be the same as the outer diameter of the paper feed roll 16. If the outer diameter of the auxiliary roll 18 is the same as the outer diameter of the paper feed roll 16, the auxiliary roll 18 also has a part of the same function as the paper feed roll 16, so the paper feed roll 16 is made shorter than before. Alternatively, the auxiliary roll 18 may be made shorter than before. Also, retard roll 1
7 may be a separation pad or other separation member.

  As described above, according to the present embodiment, as a paper feeding device that uses a half-moon paper feeding roll, a pair of auxiliary rolls, and a separation member that presses them, the paper feeding roll is integrated with a drive shaft that drives the paper feeding roll. A pair of auxiliary rolls fixed to rotate and arranged on both sides of the paper feed roll are arranged on the drive shaft via a one-way clutch. Here, the one-way clutch connects the auxiliary roll to the drive shaft to forcibly rotate when the drive shaft rotates in the paper transport direction, and the paper transported by the transport roll when the drive shaft rotation stops. It is driven to rotate (idle) with the conveyance.

  Since the auxiliary roll is forcibly rotated integrally with the rotation of the drive shaft during the paper feeding operation, even if the convex portion of the corrugated paper is at the auxiliary roll position, the paper is conveyed by the auxiliary roll and is not No feed occurs. In addition, since the auxiliary roll is arranged on the drive shaft via the one-way clutch, the auxiliary roll after the drive shaft stops can be idled, and can be transported by the transport roll downstream (conveyance destination). Followed rotation (idling). Therefore, the load on the transport roll is reduced and the influence on the paper running accuracy is reduced.

  Furthermore, the outer roll outer material is made of the same material as the outer circumference of the half-moon-shaped paper feed roll so that the wear rate is the same. You can keep the difference.

  As shown in FIGS. 2 and 3, the image forming apparatus using the sheet feeding device according to the present embodiment includes a paper discharge tray 14 formed at the top of the housing, and a door body that can be opened and closed on the front surface of the housing. 15 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 member 4 made 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 disposed.

  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 provided 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 photosensitive member 3, a charging device (not shown) for uniformly charging the photosensitive member 3 along the rotation direction, an exposure device 5 for forming a latent image on the photosensitive member 3, a latent device 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 control of the drive motor and bias 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 rotational movement direction of the rotary developing device 1, the developing roll or rollers disposed on 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 supply devices 9 and 10 is conveyed from the conveyance path to the secondary transfer device 8 through the paper supply roll 16, the conveyance roll, and the registration roll 11. The apparatus 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 apparatus 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 ... feed roll, 17 ... retard roll, 18 ... auxiliary roll, 20 ... bottom plate, 16
1 ... Drive shaft, 181 ... One-way clutch

Claims (7)

A half-moon-shaped paper feed roll;
A pair of auxiliary rolls arranged on both sides of the paper feed roll;
A one-way clutch disposed between the drive shaft of the paper feed roll and each of the auxiliary rolls;
A separation member that presses against the paper feed roll or the auxiliary roll, and the one-way clutch moves the auxiliary roll to the drive shaft so that the auxiliary roll integrally rotates in a direction in which the drive shaft rotates by a paper feed operation. And the auxiliary roll is released from the connection with the drive shaft so that the auxiliary roll is driven to rotate in the direction in which the paper is conveyed. The paper feeding device according to claim 1, wherein the outer peripheral surface of the auxiliary roll is made of the same material as the outer peripheral surface of the paper feeding roll. The sheet feeding device according to claim 1, wherein the separation member is a separation roll. The sheet feeding device according to claim 1, wherein the separation member is a separation pad. The paper feeding device according to claim 1, wherein an outer diameter of the auxiliary roll is smaller than an outer diameter of the paper feeding roll. The paper feeding device according to claim 1, wherein an outer diameter of the auxiliary roll is the same as an outer diameter of the paper feeding roll. An image forming apparatus using the paper feeding device according to claim 1.

Images